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Use of Silicon in Containerized Systems and the Molecular Basis of Silicon-Induced Disease Resistance

Permanent Link: http://ufdc.ufl.edu/UFE0022899/00001

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Title: Use of Silicon in Containerized Systems and the Molecular Basis of Silicon-Induced Disease Resistance
Physical Description: 1 online resource (174 p.)
Language: english
Creator: Brunings, Asha
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2008

Subjects

Subjects / Keywords: expression, exserohilum, magnaporthe, resistance, silicon, tigergrass
Plant Pathology -- Dissertations, Academic -- UF
Genre: Plant Pathology thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Silicon benefits many monocotyledonous and some dicotyledonous plants, by increasing their resistance to fungal pathogens. For example, silicon increases the resistance of rice (Oryza sativa L.) to the rice blast pathogen Magnaporthe grisea. This study sought to add to the list of host-pathogen systems for which silicon is beneficial, and described the relationship between silicon and M. grisea in terms of whole-genome gene expression. Three ornamental dicotyledonous ornamental plants, and a monocotyledonous ornamental, were evaluated for silicon uptake. The plants were grown in containerized systems with soilless medium and supplied with silicon as medium-incorporated calcium silicate, or as drench-applied potassium silicate. Begonia sp. and Tagetes sp. did not take up silicon in a rate-dependent manner, while there was weak support for a rate-dependent silicon uptake of Impatiens sp. The ornamental monocotyledonous plant tigergrass (Thysanolaena maxima) accumulated silicon in a rate-dependent manner with an estimated maximum of 1.71 % (cg/gm dry weight) silicon at an amendment level of 2.30 kg elemental silicon/m3. The fungal plant pathogen Exserohilum rostratum was identified as the causal agent of tigergrass leaf spot. Spray-inoculation of E. rostratum on tigergrass resulted in symptoms as early as 12 hours after inoculation. Silicon amendment increased resistance of tigergrass to E. rostratum inoculation. The onset of disease was delayed up to two days, and the area under disease progress curve was 46 and 86 % lower in two separate experiments, even though the final disease severity did not significantly change. By assessing gene expression patterns in the rice cultivar Monko-to using microarray technology, the physiological basis for silicon-induced resistance was investigated. Silicon amendment resulted the differential regulation of 221 genes in rice without being challenged with the pathogen. This means that silicon had an observable effect on rice metabolism, as opposed to playing a simple passive role in the resistance response of rice. Compared to control plants, silicon-amended rice differentially regulated 60% less genes, implying that silicon affects the rice response to rice blast infection at a transcriptional level.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Asha Brunings.
Thesis: Thesis (Ph.D.)--University of Florida, 2008.
Local: Adviser: Jones, Jeffrey B.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2010-12-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2008
System ID: UFE0022899:00001

Permanent Link: http://ufdc.ufl.edu/UFE0022899/00001

Material Information

Title: Use of Silicon in Containerized Systems and the Molecular Basis of Silicon-Induced Disease Resistance
Physical Description: 1 online resource (174 p.)
Language: english
Creator: Brunings, Asha
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2008

Subjects

Subjects / Keywords: expression, exserohilum, magnaporthe, resistance, silicon, tigergrass
Plant Pathology -- Dissertations, Academic -- UF
Genre: Plant Pathology thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Silicon benefits many monocotyledonous and some dicotyledonous plants, by increasing their resistance to fungal pathogens. For example, silicon increases the resistance of rice (Oryza sativa L.) to the rice blast pathogen Magnaporthe grisea. This study sought to add to the list of host-pathogen systems for which silicon is beneficial, and described the relationship between silicon and M. grisea in terms of whole-genome gene expression. Three ornamental dicotyledonous ornamental plants, and a monocotyledonous ornamental, were evaluated for silicon uptake. The plants were grown in containerized systems with soilless medium and supplied with silicon as medium-incorporated calcium silicate, or as drench-applied potassium silicate. Begonia sp. and Tagetes sp. did not take up silicon in a rate-dependent manner, while there was weak support for a rate-dependent silicon uptake of Impatiens sp. The ornamental monocotyledonous plant tigergrass (Thysanolaena maxima) accumulated silicon in a rate-dependent manner with an estimated maximum of 1.71 % (cg/gm dry weight) silicon at an amendment level of 2.30 kg elemental silicon/m3. The fungal plant pathogen Exserohilum rostratum was identified as the causal agent of tigergrass leaf spot. Spray-inoculation of E. rostratum on tigergrass resulted in symptoms as early as 12 hours after inoculation. Silicon amendment increased resistance of tigergrass to E. rostratum inoculation. The onset of disease was delayed up to two days, and the area under disease progress curve was 46 and 86 % lower in two separate experiments, even though the final disease severity did not significantly change. By assessing gene expression patterns in the rice cultivar Monko-to using microarray technology, the physiological basis for silicon-induced resistance was investigated. Silicon amendment resulted the differential regulation of 221 genes in rice without being challenged with the pathogen. This means that silicon had an observable effect on rice metabolism, as opposed to playing a simple passive role in the resistance response of rice. Compared to control plants, silicon-amended rice differentially regulated 60% less genes, implying that silicon affects the rice response to rice blast infection at a transcriptional level.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Asha Brunings.
Thesis: Thesis (Ph.D.)--University of Florida, 2008.
Local: Adviser: Jones, Jeffrey B.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2010-12-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2008
System ID: UFE0022899:00001


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1 USE OF SILICON IN CONTAINERIZED SYSTEMS AND THE MOLECULAR BASIS OF SILICON INDUCED DISEASE RESISTANCE By ASHA MARCELLE BRUNINGS A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFIL LMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2008

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2 2008 Asha Marcelle Brunings

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3 To Mireille Ernestine Marcelle Brunings Stolz In Memory of Raoul Ernesto Brunings (16 November 1972 21 August 1991) an d Ernie Adolf Brunings (20 November 1944 20 June 2007)

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4 ACKNOWLEDGMENTS First of all I would like to thank my committee members for their support throughout my program. My adviser, Dr. Lawrence E. Datnoff, has always been tremendously supportive, en couraging me when I was up, cheering me on when I was down. Dr. Datnoff always believed in me, his confidence pushed me through. When I told him I could use a couple of pages to acknowledge his support over the years, he insisted on keeping it to a couple of sentences. He certainly deserves more, but in the interest of space I concur. More than simply the chair of my committee and my major adviser, he has been a true mentor, praising what I did right, and criticizing my mistakes. Dr. Jeffrey Jones has been an amazing source of strength and technical advice. Dr. Jones always managed to come up with control tests that I had not thought of and his suggestions greatly increased the value of my research. My other committee members, Drs. Jeffrey Rollins an d Eric Simonne have also been extremely helpful and encouraging. Dr. Terrill Nell served on my committee for a long time, and I am grateful for the unique perspective he has offered. Many thanks go out to Dr. James Locke, plant pathologist for the greenhouse pro duction research group at the United States Department of Agriculture in Toledo, OH for allowing me the opportunity to do this project and providing funding. I thank Dr. Wen Yuan Song, who graciously provided use of his well equipped growth room for many m onths. I thank Dr. Aaron Palmateer, for providing me with samples of tigergrass leaves to jumpstart the true plant pathological aspect of my research. I would like to thank the chair of the University of Florida Plant Pathology department, Dr. R. Charudatt an, the former chair Dr. Gail Wisler, and the support staff Ms. Donna Reed, Gail Harris, Lauretta Rahmes, and Jan Sapp for everything they have done over the years. I am grateful to Eldon Philman and Herman Brown who have helped me in so many ways over the years with medium preparation and much more at the plant pathology greenhouse complex.

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5 Speedling (Sun City, FL) donated many trays of beautifully uniform ornamentals for experiments described in Chapter 2. AgriStarts III likewise donated numerous ornament al tigergrass plants for use. Dan Hartman from AgriStarts III was very helpful in providing information on their greenhouse fungal control spray schedule. Gary Marlow deserves special mention. He was my surrogate father for many years and always believed i n me. Without his support over the years, technically, emotionally, and financially, I would never have been able to finish. He recently retired and I wish him all the best in his new endeavors, and hope he manages to read all the books he wants to read an d more. More thanks go out to my colleagues in Dr. Datnoffs laboratory. Brenda Rutherford, senior biological scientist has been tremendously helpful over the years. The same goes to my fellow students in the lab Linley Dixon, Norma Flor, Cheng Hua Huang, Ernane Lemes, and Jessica Palenchar. My thanks to my entire family for support and encouragement: Henna, Ninon, and Thea Brunings, Pearl Brunings, Danielle and Derrick Klaverweide, Erica Stolz, Oma Rob Stolz, Oma Leonie Cheu Choi. Many thanks also to my hu sbands family: Heidy, Tom, and Kelly Meier, Heinz and Elsbeth Kupka. My colleagues, too numerous to mention, but you know who you are, I appreciate all the support. My brother thought I was the second smartest person he knew (our parents shared the first spot), and I am happy he is not here to be disabused of that opinion, but sad that he cannot see for himself what I did accomplish. I may not be the smartest person in the world, but I did learn something from him about perseverance. My father Ernie and my mother Mireille, have always believed in me, and supported every decision I made, no matter how outrageous they thought my

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6 decisions were sometimes. And even though my father is no longer around to read this, I thank both of them with all my heart. Words cannot describe how indebted I am to my family. I will spend the bulk of my professional career trying to prove that the sacrifices were all worth it. Jim, my husband has taken the seat next to me on the roller coaster ride of my life, and has hung on tigh t. His love, encouragement, and understanding have been invaluable. My children, Raoul, Marlow, and Nikhita, always made sure I got the necessary distractions from my work. They kept it all real, and made sure I realized what is truly important.

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7 TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ ............... 4 LIST OF TABLES ................................ ................................ ................................ ........................... 9 LIST OF F I GURE S ................................ ................................ ................................ ....................... 11 ABSTRACT ................................ ................................ ................................ ................................ ... 13 CHAPTER 1 L ITERATURE REVIEW ................................ ................................ ................................ ....... 15 Silicon in Soils ................................ ................................ ................................ ........................ 16 The Silicon Cycle ................................ ................................ ................................ ................... 18 Silicon Uptake by the Plant ................................ ................................ ................................ .... 18 Silicon uptake ................................ ................................ ................................ .................. 18 S ilicon transporters ................................ ................................ ................................ .......... 19 Silicon transport and deposition ................................ ................................ ...................... 20 Benefits of Silicon ................................ ................................ ................................ .................. 20 Proposed Resistance Mechanisms ................................ ................................ .......................... 23 Mechanical barrier ................................ ................................ ................................ ........... 23 Physiological modifier ................................ ................................ ................................ ..... 24 Hypotheses ................................ ................................ ................................ .............................. 25 2 SILICON AMENDMENT OF GROWING MEDIUM FOR THE CULTURE OF ORNAMENTAL DICOTYLEDONOUS PLANTS IN CONTAINERIZED SYSTEMS ..... 28 Introduction ................................ ................................ ................................ ............................. 28 Materials and Methods ................................ ................................ ................................ ........... 30 Soil silicon measurements ................................ ................................ ............................... 31 Leaf silicon measurements ................................ ................................ .............................. 32 Results ................................ ................................ ................................ ................................ ..... 33 Begonia ................................ ................................ ................................ ............................ 33 Impatiens ................................ ................................ ................................ ......................... 35 Marigold ................................ ................................ ................................ .......................... 37 Tigergrass ................................ ................................ ................................ ........................ 38 Discussion ................................ ................................ ................................ ............................... 39 3 EFFECT OF SILICON ON TIGERGRAS S DISEASE RESISTANCE AGAINST TIGERGRASS LEAF SPOT ................................ ................................ ................................ .. 59 Introduction ................................ ................................ ................................ ............................. 59 Exserohilum rostratum ................................ ................................ ................................ .... 59 Silicon in tigergrass ................................ ................................ ................................ ......... 61

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8 Materials and Methods ................................ ................................ ................................ ........... 62 Pathogen Characterization ................................ ................................ ............................... 62 Fungal Growth on Soluble Silicon ................................ ................................ .................. 64 Effect of Silicon on Disease Development ................................ ................................ ...... 65 Results ................................ ................................ ................................ ................................ ..... 67 Pathogen Identification ................................ ................................ ................................ .... 67 Fungal Characterization ................................ ................................ ................................ ... 68 Effect of Soluble Silicon on Fungal Growth In Vitro ................................ ...................... 69 Effect of Silicon on Resistance of Tigergrass t o Exserohilum rostratum ...................... 71 Discussion and Conclusions ................................ ................................ ................................ ... 73 4 EFFECT OF SILICON AMENDMENT ON GENE EXPRESSION PATTERNS IN RICE ................................ ................................ ................................ ................................ ..... 100 Introduction ................................ ................................ ................................ ........................... 100 Materials and Methods ................................ ................................ ................................ ......... 102 Results ................................ ................................ ................................ ................................ ... 103 Silicon amendment ................................ ................................ ................................ ........ 104 Pathogen inoculation ................................ ................................ ................................ ..... 104 Silicon pathogen interaction ................................ ................................ .......................... 105 Discussion and Conclusions ................................ ................................ ................................ 106 5 CONCLUSION ................................ ................................ ................................ ..................... 119 Silicon in Ornamentals ................................ ................................ ................................ ......... 119 Exserohilum rostratum on Tigergrass ................................ ................................ .................. 121 The Transcrip tional Response of Rice to the Silicon Pathogen Interaction ......................... 123 APPENDIX EXPRESSION PROFILE OF DIFFERENTIALLY EXPRESSED GENES .............................. 126 REFERENCES ................................ ................................ ................................ ............................ 164 BIOGRAPHICAL SKETCH ................................ ................................ ................................ ....... 174

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9 LIST OF TABLES Table page 2 1 Effect of silicon rate on percent dry weight accumulation of silicon in begonia .................... 45 2 2 Dry weight and silicon concentration of begonia leaves grown at 0 and 1.87 kg elemental silicon/m 3 ................................ ................................ ................................ ........... 45 2 3 Effect of different silicon sources applied at a rate of 1.40 kg elemental silicon/m 3 on growing medium pH, EC, and begonia dry weight and silicon concentrat ion (first experiment) ................................ ................................ ................................ ........................ 45 2 4 Effect of different silicon sources applied at a rate of 1.40 kg elemental silicon/m 3 on growing medium pH, EC, and begonia dry weight and silicon concentration (second experiment) ................................ ................................ ................................ ........................ 45 2 5 Silicon concentration of impatiens leaves grown in medium amended with different levels of Wollastonite ................................ ................................ ................................ ........ 46 2 6 Silicon concentration of impatiens leaves grown at 0 and 1.87 kg elemental silicon/m 3 ........ 46 2 7 Silicon concentration in impatiens grown in medium amended with different sources of silicon at a rate of 1.40 kg elemental silicon/m 3 (first experiment) ................................ ... 46 2 8 Silicon concentration in impatiens grown in medium amended with different sources of silicon at a rate of 1.40 kg elemental silicon/m 3 (second experiment) .............................. 46 2 9 Silicon concentrati o n in the leaves of marigold grown in pots amended with different levels of silicon ap plied as Wollastonite ................................ ................................ ............ 47 2 10 Dry weight and silicon concentration of marigold leaves grown at 0 and 1.87 kg elemental silicon/m 3 ................................ ................................ ................................ ........... 47 2 11 Silicon concentration of marigold amended with different sou rces of silicon applied at 1.40 kg elemental silicon/m 3 (first experiment) ................................ ................................ 47 2 12 Silicon concentration of leaf tissue of marigold amended with different sources of silicon applied at 1.40 kg silicon/m 3 (second experiment) ................................ ................ 47 2 13 Silicon concentration of tigergrass leaves for different levels of medium amendment with Wollastonite (first experiment) ................................ ................................ .................. 48 2 14 Silicon concentration of tigergrass leaves for different levels of medium amendment with Wollastonite (second experiment) ................................ ................................ ............. 48 2 15 Silicon accumulation of tigergrass grown with different sources of silicon at a rate equivalent to 1.40 kg elemental silicon/m 3 ................................ ................................ ........ 48

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10 3 1 Effect of potassium hydroxide and potassium silicate on colony diameter and percent inhibition of growth of Exserohilum rostratum after 5 days, first experiment .................. 79 3 2 Effect of potassium hydroxide on colony diameter and per cent inhibition of growth of Exserohilum rostratum after 5 days, second experiment ................................ ................... 79 3 3 Effect of potassium hydroxide on colony diameter of Exserohilum rostratum after 5 days, third experiment ................................ ................................ ................................ ........ 80 3 4 Silicon concentration (cg/gm) of Exserohilum rostratum grown on V 8 juice agar with soluble silicon amendment ................................ ................................ ................................ 80 3 5 Silicon concentration of tigergrass leaves at the time of inoculation (day 0) and the time of harvest (day 14), first experiment ................................ ................................ .................. 80 3 6 Silicon concentration of tigergrass leaves at the time of inoculation (day 0) and the time of harvest (day 19), second experiment ................................ ................................ ............. 81 4 1 Microarray experiment treatment s ................................ ................................ ......................... 111 4 2 Number of up and down regulated genes unique for each comparison of treatments ......... 111 4 3 Categories of differentially expressed genes for each treatment comparison ....................... 111 5 1 Contributions to science for each chapter ................................ ................................ .............. 125 A 1 Expression profile of defense and/or stress related genes ................................ .................... 127 A 2 Expression profile of transcription factor encoding genes ................................ ................... 131 A 3 Expression profile of transporter encoding genes ................................ ................................ 134 A 4 Expression profile of hormone pathway related genes ................................ ........................ 135 A 5 Expression profile of housekeeping genes ................................ ................................ ........... 136 A 6 Expression profile of cytochrome P450 encoding genes ................................ ..................... 145 A 7 Expression profile of genes encoding proteins involved in protein protein interactions and/or protein turnover ................................ ................................ ................................ .... 146 A 8 Expression profile of genes involved in calcium signaling/binding ................................ ..... 147 A 9 Expression profile of kinase/phosphatase encoding genes ................................ ................... 148 A 10 Expression profile of genes with unknown function ................................ .......................... 151

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11 LIST OF FIGURES Figure page 1 1 Soil orders and the ir general degree of weathering ................................ ................................ 27 2 1 Experimental setup for marigolds in the greenhouse ................................ .............................. 49 2 2 Experimental setup of begonia, marigold, and impatiens containers in the climate controlled growth room with fluorescent lighting ................................ ............................. 50 2 3 Silicon concentration of begonia leaves and stems after four weeks o f growth on different levels of silicon amendment ................................ ................................ ................ 51 2 4 Begonia plants treated with different sources of silicon after four weeks of growth .............. 52 2 5 Silicon concentration of impatiens leaves and stem s after four weeks of growth on different levels of silicon amendment ................................ ................................ ................ 53 2 6 Impatiens plants amended with different sources of silicon after four weeks of growth ........ 54 2 7 Silicon concentration of mar igold leaves after four weeks of growth on different levels of silicon amendment ................................ ................................ ................................ ......... 55 2 8 Marigold plants amended with different sources of silicon after four weeks of growth ......... 56 2 9 Rate dependent sil icon accumulation of tigergrass ( f irst experiment) ................................ .... 57 2 10 Rate dependent silicon accumulation of tigergrass (second experiment) ............................. 58 3 1 Shelf enclosed in plastic used for keeping plants at high humi dity for the first 24 hours after inoculation. ................................ ................................ ................................ ................ 82 3 2 Tigergrass showing leaf spot symptoms on day of receipt from the supplier ......................... 83 3 3 Conidia of Exserohilum rostratum ................................ ................................ .......................... 84 3 4 Bipolar conidial germination of Exserohilum rostratum ................................ ........................ 85 3 5 The effect of inoculum density on Exserohilum rostratum leaf spot development on tigergrass ................................ ................................ ................................ ............................ 86 3 6 ITS sequence alignment. ITS1/4 sequences derived from Exserohilum rostratum isolate 0706019 compared with the ITS sequence from GenBank gi:76555872 Exserohilum rostratum ................................ ................................ ................................ ........................... 87 3 7 Association of conidia of Exserohilum rostratum with lesions on tigergrass ......................... 88

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12 3-8 Exserohilum rostratum forms distinct appressoria (arrows) in the process of infecting tigergrass............................................................................................................................89!3-9 Growth of Exserohilum rostratum on V8-juice agar amended with soluble silicon (AgSil) or potassium hydroxide (KOH) first experiment..........................................90!3-10 Growth of Exserohilum rostratum on V8-juice agar amended with soluble silicon (AgSil) or potassium hydroxide (KOH), second experiment....................................91!3-11 Growth of Exserohilum rostratum on V8-juice agar amended with soluble silicon (AgSil) or potassium hydroxide (KOH), third experiment........................................92!3-12 Growth inhibition of Exserohilum rostratum in vitro on medium containing soluble silicon.................................................................................................................................93!3-13 Development of tigergrass leaf spot severity caused by Exserohilum rostratum (5 103) over a 14-day period...................................................................................................94!3-14 Final Area Under Disease Progress Curve (AUDPC) for tigergrass leaf spot caused by Exserohilum rostratum, first experiment...........................................................................95!3-15 Final tigergrass leaf spot severity caused by Exserohilum rostratum, first experiment........96!3-16 Development of tigergrass leaf spot severity caused by Exserohilum rostratum (5 103) over a 19-day period...................................................................................................97!3-17 Final Area Under Disease Progress Curve (AUDPC) for tigergrass leaf spot, 19 days after inoculation, second experiment.................................................................................98!3-18 Final disease severity of tigergrass at 19 days after inoculation with Exserohilum rostratum, second experiment............................................................................................99!4-1 The number of differentially expressed genes for each treatment comparison.....................112!4-2 Volcanoplot C vs Si...............................................................................................................113!4-3 Volcanoplot P vs SiP.............................................................................................................114!4-4 Volcanoplot C vs P................................................................................................................115!4-5 Volcanoplot Si vs SiP............................................................................................................116!4-6 The distribution of differentially expressed genes for each of the treatment comparisons...117!4-7 Number of unique and overlapping genes for each comparison combination......................118!

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13 Abstract of Dissertation Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy USE OF SILICON IN CONTAINERIZED SYSTEMS AND THE MOLECULAR BASIS OF SILICON INDUCED DISEASE RESISTANCE By Asha Marcelle Brunings December 2008 Chair: Lawrence Elliot t Datnoff Major: Plant Pathology Silicon benefits many monocotyledonous and some dicotyledonous plants, by increasing their resistance to fungal pathogens. For example, silicon increases the resistance of rice ( Oryza sativa L.) to the rice blast pathogen Magnaporthe grisea This study sought to add to the list of host pathogen systems for which silicon is beneficial, and described the relationship between silicon and M. grisea in terms of whole genome gene expression. Three ornamental dicotyledonous orname ntal plants, and a monocotyledonous ornamental, were evaluated for silicon uptake. The plants were grown in containerized systems with soilless medium and supplied with silicon as medium incorporated calcium silicate, or as drench applied potassium silicat e. Begonia sp. and Tagetes sp. did not take up silicon in a rate dependent manner, while there was weak support for a rate dependent silicon uptake of Impatiens sp. The ornamental monocotyledonous plant tigergrass ( Thysanolaena maxima ) accumulated silicon in a rate dependent manner with an estimated maximum of 1. 7 1 % (cg/ g m dry weight) silicon at an amendment level of 2.30 kg elemental silicon/ m 3 The fungal plant pathogen Exserohilum rostratum was identified as the causal agent of tigergrass leaf spot. Spr ay inoculation of E. rostratum on tigergrass resulted in symptoms as

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14 early as 12 hours after inoculation. Silicon amendment increased resistance of tigergrass to E. rostratum inoculation. The onset of disease was delayed up to two days, and the area under disease progress curve was 46 and 86 % lower in two separate experiments, even though the final disease severity did not significantly change. By assessing gene expression patterns in the rice cultivar Monko to using microarray technology, the physiologica l basis for silicon induced resistance was investigated. Silicon amendment resulted the differential regulation of 221 genes in rice without being challenged with the pathogen. This means that silicon had an observable effect on rice metabolism, as opposed to playing a simple passive role in the resistance response of rice. Compared to control plants, silicon amended rice different ially regulated 60% less genes, implying that silicon affects the rice response to rice blast infection at a transcriptional lev el.

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15 CHAPTER 1 LITERATURE REVIEW Silicon is not an essential element according to the criteria proposed by Arnon and Stout (1939) who stated that an element is not considered essential unless: Deficiency makes it impossible for the plant to complete the v egetative or reproductive stage of its life cycle. The deficiency is specific to the element and can only be corrected by applying the element in question. The element is directly involved in the nutrition of the plant, apart from its possible effects in c orrecting some unfavorable microbiological or chemical condition of the soil or other culture medium. However, Epstein (1999) e mphasized that it is virtually impossible to exclude silicon, the second most abundant element in the Earth s crust, from field e xperiments; the refore silicon deficiencies were not apparent until culture in artificial nutrient solutions became common. Even then, enough silicon occurs in water, or becomes available from glass containers to make complete exclusion of silicon from the culture of crops difficult if extraordinary measures are not taken to avoid silicon contamination. For example, Raleigh (1939) studied the role of silicon for growth of beets in asphalt painted iron containers, and potassium silicate was purified and col lected in platinum ware. Silicon can also be present as an impurity of other nutrients supplied. Even so, in practice, most plants grow normally in nutrient medium to which silicon has not been added, but those conditions are also experimental artifacts (E pstein 1999), and do not faithfully mimic the natural environment. Epstein (2001) argues that if silicon, an element that accumulates to levels as high as, or even higher than the levels of other macronutrients in plants, is not considered essential, the d efinition of what is an essential element is inadequate.

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16 Silicon in Soils Silicon (Si; atom number 14, atomic weight 28 gm) makes up approximately 28% of the Earths crust, second only after oxygen, which makes up about 46% (CRC handbook of Chemistry and P hysics. 85 t h Ed. CRC Press, Boca Raton, Florida, Section 14, 2005). Consequently, silicon is a major constituent of soils. The twelve officially recognized soil orders (see Figure 1 1) contain varying amounts of Si, depending on their degree of weathering. During the weathering process many minerals newly derived from the parent material leach ou t of the soil profile (Jenny 19 4 1 ). However, the absolute content of a particular compound is not very useful when studying leaching, because in addition to leachin g out of minerals, organic material is often added to the soil. To assess leaching, the ratios of minerals are more informative. An example is the SiO 3 /Al 2 O 3 ratio. When soil is assessed some years apart, a smaller ratio during the second assessment would indicate a relative enrichment of the soil for Al 2 O 3 and therefore, leaching of SiO 2 (Brady and Weil 2002; Jenny 19 4 1 ). The parent so il always has relatively more silicon than the weathered products, indicative of silicon leaching Orders with the most hi ghly weathered soils are usually associated with warmer and wetter climates (Brady and Weil 2002). Ultisols and Oxisols are the most weathered soils, low in plant available silicon and mostly found in warm and wet climates (Brady and Weil 2002; Datnoff an d Rodrigues 2005). Weathering of rocks involves hydrolysis of minerals. F or example, the weathe ring of microcline, a potassium containing feldspar, results in the release of monosilicic acid into the soil solution and occurs in two steps. KAlSi 3 O 8 + H 2 O HAlSi 3 O 8 + K + + OH 2HAlSi 3 O 8 +11H 2 O Al 2 O 3 +6H 4 SiO 4

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17 Similarly, hydrolysis of muscovite solid, results in the release of H 4 SiO 4 into the soil solution, while hydrolysis of olivine solid, releases SiO 2 into solution. SiO 2 in turn, can react with water to form mo nosilicic acid, which enters the soil solution (Epstein 2001). SiO 2 +2H 2 O H 4 SiO 4 This disassociates as follows: Si(OH) 4 + H 2 O (OH) 3 SiO 1 + H 3 0 + Most soil solutions contain 0.1 0.6 mM silicon (Epstein 1994). The effective concentration of monosilicic aci d in soils depends on the presence of quartz and amorphous silica. Contrary to monosilicic acid, quartz (SiO 2 ) is highly insoluble (Epstein 2001). In the presence of quartz, the chemical reaction moves to the left, and the monosilicic acid concentration in the soil solution is about 0.1 mM. In the presence of amorphous silica (when the soil is supersaturated with silica), the concentration of monosilicic acid in the soil solution is about 1.8 mM (Epstein 2001). In soil solutions monomeric silicon is in equi librium with polymeric silicon (Knight and Kinrade 2001) Monosilicic acid can react with aluminum, iron, manganese, and heavy metals such as cadmium, lead zinc, and magnesium. It diss ociates into SiO 3 which can replace phosphate ions adsorbed on to soil particles, thereby releasing phosphate into the soil solution. At high pH, H 4 SiO 4 adsorption is greater. At concentrations exceeding 65 mg/L monosilicic acid polymerizes into polysilicic acid, which is chemically inert (Daroub and Snyder 2007). Although Kinrade et al. (1999) showed that silicon readily formed complexes with sugar like molecules in aqueous solutions, no such organosilicon compounds were known to form and remain thermodynamically stable under biologically relevant pH levels and silicon conc entration until two years later (Kinrade et al. 2001). Kinrade et al. (2001) suggested that such compounds could sequester silicon in groundwater and biological fluids.

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18 The Silicon Cycle The silicon cycle involves weathering of silicate rocks, which releas es silicates into the soil solution. Soluble silicon can then be bound into aluminum silicates, precipitate as amorphous silica on mineral surfaces, or be taken up by the plant (Sommer 2006). Soluble monosilicic acid taken up by plants is deposited as soli d amorphous silica (SiO 2 n H 2 O) in the cell wall matrix, cell lumen, and extracellular spaces of shoots, leaf, culm, and root tissues, and in the inflorescences of grasses (Sangster et al 2001). Neumann and De Figueiredo (2002) reported the presence of sil icon in the cytoplasm of certain heavy metal tolerant plants. Phytogenic silicon (silicon in plants) is returned to the soil by decaying plant material. Silicon can move between soil horizons, leach out (desilication), end up in waterways via runoff, and e ventually ends up in the oceans, where it may be taken up by diatoms. Sedimentation returns silicon to the Earths crust (Epstein 2001). Little is known about how much biogenic silicon contributes to silicon redistribution, or the rates, processes and driv ing forces of the silicon cycle (Sommer 2006). Silicon Uptake by the Plant Silicon uptake Silicon is taken up by plants from the growing medium in the form of silicic acid (H 4 SiO 4 ), an uncharged molecule (Ma and Yamaji 2006), mainly by the lateral roots (M a et al. 2001 a ). Active transport was theoretically necessary since the silicon concentration of plants could not be explained by passive uptake of silicon from the soil solution (Raven 2001), and was shown to occur both passively and actively in rice ( Ory za sativa L.), maize ( Zea mays L.), sunflower ( Helianthus annuus L.), wax gourd ( Benincase hispida (Thunb.) Cogn. and cucumber ( Cucumis sativus L.; Liang et al. 2006).

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19 Silicon transporters Ma et al. (2004) characterized the silicon uptake system of rice, and concluded that silicic acid is transported against a concentration gradient into the cortical cells, with a K m value of 0.15 mM. A rice mutant ( lsi1 ) deficient in silicon uptake, was identified with the silicon analog germanium by Ma et al. (2002). Pla nt roots do not discriminate between germanium and silicon, but germanium is toxic to plants. This property of germanium was used to isolate germanium insensitive mutant rice plants. The lsi1 gene was identified as a member of the aquaporin family (Luu and Maurel 2005), was constitutively expressed in roots, and controlled silicon accumulation in rice. Further characterization showed that an Lsi1 GFP fusion protein driven by the lsi1 promoter localized to the plasma membrane at the distal side of the endode rmis and exodermis of roots. Further screening of the mutant rice population yielded a second silicon transporter gene ( lsi2 ). This gene encodes a putative anion transporter A GFP gene driven by the Lsi2 promoter resulted in GFP fusion protein localizati on to the proximal side of the endodermis and exodermis (Ma et al. 2007). The localization of Lsi1 and Lsi2 on opposite sides of the same cells allows silicon to get past the casparian strips which prevent indiscriminate entry of compounds into the vascula r bundle (Ma et al. 2007 ; Ma and Yamaji 2006). Yet another transporter gene, lsi6 was discovered by sequence similarity search with lsi1 (Ma et al. 2004 ), but is not exclusively expressed in root tissue like lsi1 and lsi2 but also in the apical meristem and elongation zone of the root tip, leaf sheaths and leaf blades (Yamaji et al. 2008). Lsi6 appears to transport s ilicon out of the xylem, and to be responsible for silicon distribution in the leaf.

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20 Silicon transport and deposition While silicon flows upw ard through the xylem at a supersaturated level, polymerization may be prevented by complexes with organic substances (Sangster and Hodson 1986). Mitani and Ma (2005) identified the form of silicon in xylem sap as monosilicic acid, and the silicon concentr ation in xylem sap reached as much as 18 mM. This concentration fell back to 2.6 mM after mixing water into the nutrient solution. No complexes of silicon with organic substances were identified, as had been proposed by Sangster and Hodson (1986). However, Kinrade et al. (2001; 2004) showed that it is possible for silicon to form complexes with organic compounds under conditions similar to those occurring in the soil. Silicic acid started polymerizing once the silicon concentration reached 2 2.3 mM a t room temperature (Mitani and Ma 2005). The authors explained this discrepancy by proposing that the high silicon concentration was transient in the xylem, and that silicon was deposited in the apoplast once the concentration increases further due to water loss. Deposition of silicon has been documented in the cell wall of the epidermis by X ray analysis (Kim et al. 2002) and NMR spectroscopy (Park et al. 2006). There is also a report of silicon presence in the cytoplasm of a number of heavy metal tolerant plants and Arabidopsis thaliana (L.) Heynh. (Neumann and De Figueiredo 2002). Kim et al. (2002) measured increasing concentrations towards the outer edge of the epidermal cell wall. Benefits of Silicon Silicon has been shown to provide benefits to a variety of crops, including monocotyledons such as barley ( Hordeum vulgare subsp. vulgare L.) sugarcane ( Saccharum officinarum L.) turfgrasses, and wheat ( Triticum aestivum L.) and dicotyledons such as cucumber ( Cucumis sativus L.) Arabidopsis thaliana (L.) Heynh grape ( Vitis vinifera L. ) strawberry ( Fragaria x ananassa Duchesne) and sunflower ( Helianthus annuus L.) (Adatia and Besford 1986; Bowen et

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21 al. 1992; Menzies et al. 1991; Datnoff et al. 2001; Kamenido u et al. 2008; Kanto et al. 2007 ; Liang et al. 2005 ). Silicon has been demonstrated to increase yields (Datnoff et al. 1992; Seebold et al. 2000), make plants more resistant to lodging (Comhair e 1966), and increase resistance to drought (Epstei n 1999). Silicon also alleviates manganese toxicity (Williams a nd Vlamis 1957) and aluminum toxicity ( Britez 2002; Epstein 1999). In rice, it was shown that plant s were more erect when there was sufficient silicon, and that the distribution of light within the canopy of the rice field was improved (Ma et al. 1989; Sav ant et al. 1997). In sunflower, horticultural trai ts, such as stem diameter, flower number and height were improved by silicon amendment, depending on the source of silicon and the concentration (Kamenidou et al. 2008). However, amendment with soluble sil icon as potassium silicate drenches, resulted in stunted growth and deformed flowers Silicon decreases disease severity in many plant pathogen systems. Silicon increases rice resistance to rice blast infection ( Magnaporthe grisea (T.T. Hebert) M.E. Barr; Volk et al. 1958). Calcium silicate reduced blast and brown spot ( Bipolaris oryzae) on rice (Datnoff et al. 1991; 1992), suppressed gray leaf spot ( M. grisea ) on St. Augustinegrass ( Stenotaphrum secundatum (Walter) Kuntze. ; Brecht et al. 2004 2007 a ), decr eased gray leaf spot on perennial ryegrass turf ( ( Lolium perenne L ; Nanayakkara et al. 2008), reduced downy mildew caused by Sclerospora graminicola on pearl millet ( Pennisetum glaucum (L.) R.Br. ; Deepak et al. 2008), and powdery mildew caused by Sphaeroth eca aphanis on strawberry (Kanto et al. 2007 ). Silicon was shown to affect general of components of resistance in different plant pathogen systems. Kema et al. (1996) suggested that silicon increases the latent period of Mycosphaerella graminicola the cau sal agent of leaf blotch on wheat, while Seebold et al. (2001) found that the incubation period increased with increasing rates of silicon. Examples of

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22 silicon amendment affecting infection efficiency include the reduction of the number of sporulating lesi ons per leaf area of the rice blast pathogen M. grisea on rice (Volk et al. 1958), a result confirmed by Seebold et al. (2001), failure of powdery mildew fungus Erysiphe graminis to penetrate the epidermal cells of barley (Carver et al. 1987), decrease in lesion numbers caused by Mycosphaerella pinodes on pea leaves ( Pisum sativum L. ; Dann and M uir 2002) and for gray leaf spot on St. Augustinegrass (Brecht et al. 2007 a ), reduction in the number of Podosp h aera fuliginea colonies on cucumber leaves by 43 94% depending on the age of the leaf (Menzies et al. 1991), decrease in the number of powdery mildew ( Uncinula necator ) colonies on grape leaves (Bowen et al. 1992), and of Diplocarpon rosae (causal agent of black spot) on roses ( Rosa hybrida Meipelta; Gillm an et al. 2003). The area colonized and lesion size determines the effective area for fungal sporulation and is affected by silicon in a number of plant pathogen systems. Menzies et al. (1991) and Seebold (2001) reported decreases in the size of powdery mi ldew colonies on cucumber by 55 99% and blast lesion length by 40 80% on rice, respectively. The success of polycyclic plant pathogens depends on their ability to sporulate effectively to spread the pathogen maximally throughout the season. Podosphaera ful iginea colonies on cucumber germinated less when plants were grown with added silicon (Menzies et al. 1991), and M. grisea produced less spores per square millimeter of lesion on silicon amended rice (Seebold et al. 2001). Berger et al. (1997) proposed the rate of lesion expansion as a component of resistanc e. This decreased by 49% when 10 t/ha calcium silicate was applied to rice, compared to the non amended control (Seebold et al. 2001). The vertical lesion extension of sheath blight caused by Rhizoctonia solani was measured over time, and the resulting area under the lesion extension

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23 progress curve decreased when the rice plants were amended with silic on (Rodrigues et al. 2001, 2003b ). Proposed Resistance Mechanisms Two different, but not mutually exclusi ve mechanisms through which silicon can enhance plant resistance to pathogen infection have been proposed. The first hypothesis proposes that silica forms a mechanical barrier which prevents fungal penetration, while the second hypothesis proposes that sil icon increases plant resistance through physiological changes. Experimental e vidence exists to support both Mechanical barrier Upon translocation through the xylem, silicon wa s deposited in the leaf epi dermal cell walls (Heath 1979; Heath et al. 1992; Kim et al. 2002), and it was proposed that the silica cuticle double layer formed an impenetrable barrier against fungal penetration. Datnoff et al. (2007) suggested however, that Kim et al. ( 2002 ) did not consider the possibility that the pressure applied by the penetration peg of the blast fungus might be enough to punc ture through the silicon layer Bowen et al. (1992) sprayed soluble silicon on grape leaves, and found that this treatment inhibited powdery mildew development on the leaves. They suggested th at the silica layer that formed on the leaf surface was responsible for forming a physical barrier against fungal penetration. They also showed that silicon was deposited within the leaves at the actual fungal penetration sites, similar to the results repo rted by Kunoh and Ishizaki (1975) for barley, cucumber, morning glory ( Ipomoea nil Roth cv. Murasaki) and wheat. More recent support for the mechanical barrier hypothesis comes from research that showed that the rice blast fungal appressorium penetration was reduced at higher levels of applied silica gel (Hayasaka et al. 2008).

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24 In an experiment where soluble silicon was made available to cucumber plants and subsequently taken away, beneficial effects of silicon discontinued, even though high levels of sili con had already accumulate d in the leaves (Samuels et al. 1991). If the impenetrable barrier of silica in the epidermis was solely responsible for cucumber resistance against powdery mildew, soluble silicon would no longer have been necessary once the barr ier had been formed. Therefore, an alternative theory to the mechanical barrier hypothesis described above is that silicon plays an active role in the ability of plants to withstand pathogen infection. Physiological modifier Rodrigues et al. (2003a ) found that cells from rice plants amended with silicon accumulated amorphous material around the fungal hyphae penetrating the cell, and that fungal hyphae thus surrounded, often were empty. When this phenomenon was further studied leaf extracts from silicon a mended, pathogen inoculated plants were found to produce higher levels of phytoalexins than leaf extracts from non amended plants (Rodrigues et al. 2004). Several gene transcripts known to be involved in a plant defense response were differentially regulat ed in silicon amended, pathogen inoculated plants (Rodrigues et al. 2005). In response to the plant pathogen Blumeria graminis which causes powdery mildew on oat, an increase in the specific activity of phenylalanine ammonia lyase (PAL) was detected, and determined to be less in silicon amended plants. This implied that silicon decreased PAL activity. Hayasaka et al. (2008) who found some evidence that supported the mechanical barrier hypothesis, also concluded that silicon imparted physiological resistanc e to the rice blast fungus after penetration of the fungus, because only a fraction of the penetrated appressoria which logically were not denied entry by the physical barrier, became sporulating lesions.

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25 Hypotheses Mainly as a result of the difficulties i n preparing silicon free solutions, the essentiality of the element silicon to plant growth, and development is still in question. However, silicon has been established in a small number of plant pathogen systems to effectively resist pathogen infection, b ut the exact role of silicon remains in dispute. There is evidence of silicon playing a role in preventing and/or inhibiting fungal penetration, and at the physiological level, but these roles still are not well defined. In the second chapter, four ornamen tal plant species are tested for their ability to accumulate silicon. The hypothesis is that silicon amendment of the containerized growth medium will result in higher silicon concentration as a percentage of dry weight when the growth medium is amended wi th a source of silicate than plants that are grown without silicon amendment. This will result in recommendations regarding the usefulness of silicon amendment in containerized systems especially for ornamentals. The third chapter describes the discovery o f a leaf spot disease on the ornamental grass, tigergrass, and the isolation of a fungus from the disease lesions. Two hypotheses are tested: 1) the isolated fungus is the causal agent of the leaf spot disease on tigergrass; 2) silicon amendment increases the resistance of tigergrass against the leaf spot causal agent. This will identify a new pathogen on tigergrass, and study the potential of silicon to decrease the plant disease in question. Decreasing/limiting plant disease with silicon, may lead to less fungicide applications. In the fourth chapter the effect of silicon is studied at a physiological level. The hypothesis is that silicon affects gene expression in rice without any pathogen challenge. If this were true, this would imply that silicon perfor ms a signaling role in the plant, and might be considered essential for plant health. The second hypothesis tested in this chapter is that silicon affects the

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26 response of the rice plant to infection with the rice blast pathogen Magnaporthe grisea Such a p hysiological response can provide insight into the molecular mechanisms that are involved in silicon induced plant resistance. Data derived from this study can (upon confirmation) implicate silicon induced signaling pathways that warrant further study. Ult imately this would lead not only to a better understanding of the rice defense mechanisms, but it might also lead to new ways to induce plant resistance, by activating the defense pathways in different ways.

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27 Figure 1 1 Soil orders and their general d egree of weathering. Adapted from Brady and Weil (2002).

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28 CHAPTER 2 SILICON AMENDMENT OF GROWING MEDIUM FOR THE CULTURE OF ORNAMENTAL DICOTYLED ONOUS PLANTS IN CONT AINERIZED SYSTEMS Introduction The first indication that silicon might play a role in plan t disease dates back to 1917, when Onodera found that there was less silicon in rice plants affected by rice blast disease than in healthy plants (Ishiguro 2001). Since monocotyledonous plants, especially grasses, accumulate silicon at much higher levels t han dicotyledonous plants do research on silicon accumulation has focused less on dicotyledonous plants. Plants are considered accumulators when they have more than 1% Si and a Si/Ca ratio greater than 1; intermediate accumulators contain 0.5 1% Si, or hi gher than 1%, but have a Si/Ca ratio smaller than 1; plants with less than 0.5% Si are non accumulators (Ma et al. 2001 b ). The number of reports of dicotyled onous plants taking up silicon albeit at low levels is growing. In 1939, Raleigh reported that sili con appeared to be essential for normal growth of beet ( Beta vulgaris L.; Raleigh 1939). It became clear that the role of silicon had been underestimated when the greenhouse culture of horticultural crops in the Netherlands started using soilless medium in the 1980s (Voogt and Sonneveld 2001). When the silicon concentr ation of crops grown in soil was compared with that of crops grown on soilless medium, cucumber ( Cucumis sativus ), courgette ( Solanum melongena ), Heath aster ( Aster ericodes ), strawberry ( Fra garia x ananassa ), and rose ( Rosa sp.) had lower levels of silicon when grown in soilless medium. A number of crops did not have different silicon levels, including carnation ( Dianthus caryophyllus ), gerbera ( Gerbera sp.), lettuce ( Lactuca sativa ), and tom ato ( Lycopersicon esculentum ). Frantz et al. (2005) found that New Guinea Impatiens accumulated silicon. Takahashi and Miyake (1977) investigated the silicon concentration of different plant species grown in the same soil. They found that the average silic on concentration of

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29 accumulators was 1.96%, while that of the non accumulators was 0.25%. Highest accumulators were mosses and ferns among the lower plants, and monocotyledons among the higher plants. Hodson et al. (2005) studied the phylogenetic variation of silicon deposition by accumulating data from 125 studies, and found a correlation between higher level phylogeny and silicon accumulation. Silicon uptake in dicotyledons has been reported for a number of species in cluding cucumber (Miyake and Takahashi 1983), French bean (Heath 1979), miniature roses (Datnoff et al. 2006), New Guinea impatiens (Frantz et al. 2005), sunflower (Kamenidou 2008), and zinnia (Locke et al. 2006). Silicon amended plants have been reported to impart many beneficial characterist ics unto plants, improving resistance against both abiotic and biotic stress es (Epstein 1994, 1999). For dicotyledons in particular, silicon appears to decrease the effects of high levels of manganese, even if the crop does not accumulate silicon (Voogt an d Sonneveld 2001; Williams and Vlamis 1957). Kamenidou et al. (2008) found that silicon amendments incorporated in the soil, resulted in taller sunflower plants, while drenches with potassium silicate resulted in shorter plants, smaller flower diameter, an d deformed flowers. A growing body of literature reports that silicon application increases resistance of plants to plant pathogens or disorders in dicotyledons. The grape powdery mildew (Bowen et al. 1992), poinsettia bract necrosis (McAvoy and Bernard 19 96), rose black spot (Gillman et al. 2003), and strawberry powdery mildew (Voogt and Sonneveld 2001) complexes are good examples. An increased level of resistance against pathogen attack could reduce the amount and/or frequency of fungicide applications a nd therefore be of great economic and environmental benefit (Alvarez et al. 2004 ; Seebold et al. 2004).

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30 The goal of the experiments described in this chapter was to assess whether silicon amendment of some ornamental crops grown in containeriz ed systems w ould result in higher silicon concentration per gram of dry tissue compared to non amended plants. If such accumulation takes place, this would increase the number of plants known to accumulate silicon. Plants that accumulate silicon would then be tested f or an increased ability to resist fungal pathogens in subsequent experiments. If silicon increases the ability of plants to withstand fungal infection, this might lead to a decrease in fungicide applications in nurseries and landscapes. Materials and Metho ds Selected o rnamentals were Begonia sp., Impatiens sp., and marigold ( Tagetes sp.), and the monocotyledonous ornamental tigergrass ( Thysanolaena maxima ). For the ornamental dicotyledonous plants, the growing medium consisted of 400 ml Metro Mix (Sun Gro H orticulture Canada, Vancouver, British Columbia) or Fafard 4P Mix soilless medium (Fafard, Agawam, MA). For the growing medium for tigergrass, 19 liter (a bucket ful) of sand was mixed with 19 liter Metro Mix or Fafard soilless medium and 100 ml Osmocote ( Scotts, Marysville, Ohio). Si licon was added in the form of W ollastonite W 20 (calcium silicate, 23.4% Si, R.T. Vanderbilt Company, Inc., Norwalk, CT), Excellerator (calcium silicate, 12.0% Si, Excell Minerals, Sarver, PA), or AgSil 25 (potassium silicate, 9.7% Si, PQ Corporation, Valley Forge, PA) at different rates up to 1.87 kg elemental silicon/m 3 AgSil25 was applied as a drench twice a week at the same rate of applied elemental silicon as Excellerator and Wollastonite Control pots did not receive any amendment. All other treatments were incorporated in the soilless medium before planting. E lectrical conductivity (EC) measurements were conducted using the Fi e l d Scout Direct Soil EC probe (Spectrum Technologies, Plainfie ld, IL). Before pH measurements plants were fertilized with 1 gm/L Peters 20 20 20 solution, 1 2 hours later ~20 ml de ioniz ed water was

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31 applied to the pot and the pH of the flow through was measured using the Ultrabasic UB 10 pH/mV meter (Denver Instrument Company, Arvada, CO). Plants were placed into 100 mm Azalea pots (Kord Products, Toronto, Ontario, Canada) immediately after mixing the treatment with the growing medium The first AgSil25 application was added to the pots immediately after planting. Pots were placed in a climate con trolled growth room with shelf systems and artificial lighting at levels of 4500 6000 lux (Extech Instruments Light Meter, Waltham, MA), where the temperature was maintained at 21 30 C; lights were on for 12 hours (Figures 2 1 and 2 2). AgSil25 was applied twice a week at a rate equivalent to 1.4 0 kg elemental s i licon/m 3 All pots were fertilized once a week with Peters 20 20 20 solution (The Scotts Company LLC, Marysville, Ohio) at a nitrogen level of 200 ppm (1 gm Peters /L). Samples of the soilless med ium were dried at 80 C for 3 4 days, passed through a #10 (2 mm) sieve and processed at the University of Floridas Everglades Research and Education Center Soil Testing Laboratory in Belle Glade for analysis of pH, and Si, Mg, and Ca concentration at the beginning of the experiment and after harvest ing of plant material at the end of the experiment. The method of analysis described below was obtained from the Soil Testing Laboratory, and were updated on July 7, 2007. Soil silicon measurements A measuring scoop was used to place 10 ml of each screened (10 mesh, 2 mm) medium sample into a 25 200 mm glass tube, and 25 ml 0.5 N acetic acid was added as extraction reagent. The tubes were capped and shaken to completely wet the so il, allowed to stand for 20 h o urs and shaken for 50 min on end to end shaker. The extracts were filtered and collected.

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32 Silicon standards of 0, 0.1, 0.2, 0.5, 0.75, and 1.0 mg/L silicon were prepared from a 1000 ppm silicon reference standard s olution (Fisher Scientific, Fair Lawn, NJ ), and treated the same way as the sample extracts for colorimetric measurements (Elliott and Snyder 1991). Of the extracts, 250 l was pipetted into a 20 mL plastic scintilliation vial (Fisher Scientific, Pittsburgh, PA) 10 ml of water added, and mixed. For colorimetric analysis 150 l of 1:1 hydrochloric acid dilution and 500 l of 10% ammonium molybdate (adjusted to pH 7.8 with sodium hydroxide) were added and allowed to stand for 5 minutes. Five hundred microliters of 20% tartaric acid was added, and the vials wer e allowed to stand for 2 min before adding 500 l reducing agent. Reducing agent consisted of a mixture of two solutions: (A) 1.6 gm 1 amino naphtol 4 sulfonic acid and 0.8 gm sodium sulfite in 10 ml water, and (B) 100 gm sodium bisulfite in 8 00 ml water. After mixing the t wo solutions, the total volume wa s brought to 1000 ml with de ionized water. V ials were allowed to stand for 5 minutes and were read within 30 minutes after adding the reducing agent. Absorbance was measured using a Brinkmann PC910 colorimeter at a wavelength of 670 nm A regression was done using the silicon standards to ca librate the probe. The results we re calculated as mg Si/L using the following equation : (10250/250) 2.5 slope absorbance. Leaf silicon measurements Leaf silicon me asurement relied on the same colorimetric procedure as described for soil analysis, and was modified from Elliott and Snyder (1991). Plant tiss ue was dried in paper bags in a dry heat oven (Isotemp Oven, Fisher Scientific) at 80 C to constan t weight (2 3 days) The dry tissue was ground using a Cyclotec 1093 sample mill (FOSS, Denmark), and stored in 20 ml plastic scintillation vials (Fisher Scientific, Pittsburgh, PA). From the dried, ground material, 100 mg was transferred to a 100 ml plastic high speed polypropylene copolymer tube (Nalgene)

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33 for digestion, the top part of which had been rinsed prior in 0.1 M NaOH solution. This minimize d undigested plant material adhering near the top of the tube. Two ml of a 50% H 2 O 2 solution were added to each tube, followed by 3 ml of 100% Na OH. The tubes were then placed for 1 hour in a 100 C water bath to initiate the tissue digestion. Then 2 ml of a 50% H 2 O 2 were added to each tube. The tissue containing tubes were autoclaved for 20 min, cooled to room temperature and mixed using a vortex. If the tissue was not completely digested, an additional 2 ml of H 2 O 2 were added and the autoclave cycle repeated. Samples typically took 4 6 rounds of H 2 O 2 addition and autoclaving for complete digestion The volume of the tissue digest was adjusted to 5 0 ml with de ionized water, and thoroughly mixed Twenty ml was transferred to a 20 ml plastic scintillation vial (Fisher Scientific) for storage. For silicon concentration determination, an aliquot of 100 l of the digested and dilu ted tissue were transfe rred to a new plastic vial, diluted 101 fold by adding 10 ml de ionized water. One way statistical analysis of variance ( ANOVA ) was performed using Statistical Analysis S oftware (SAS ; SAS Institute, Cary, NC). Results Begonia There was no statistically sig nificant difference in the leaf silicon concentration of the treatments for leaves and stems (Table 2 1) Regression analysis did not support a linear curve with a slope significantly different from zero (R 2 =0.0899 ), the estimated intercept for that model was 0.130 There was also no statistical support for a quadratic curve (R 2 =0.0997). The estimated intercept for the quadratic model was 0 .134, and is shown in Figure 2 3 To confirm these results, the experiment was repeated using amendment levels of 0 and 1. 87 kg elemental silicon / m 3 (Table 2 2) to confirm the lack of difference in accumulation between control plants and plants amended with a high level of silicon. No statistically significant differences were

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34 found in the silicon concentration of the leav es obtained from plants grown at the two different silicon levels. In all three experiments, silicon amendment of the medium did not affect the average dry weight of the silicon amended plants compared to the control plants. To assess whether different sou rces of silicon might result in accumulation of silicon in begonia, experiments were performed in which begonia was grown on shelves in a climate controlled growth room. The treatments consisted of a non amended control, and amendment of the growing medium with Wollastonite, Excellerator, and AgSil25 to a level of 1.4 0 kg elemental s i licon/m 3 The experiment was done twice and results are listed in Tables 2 3 and 2 4. Contrary to the results with Wollastoni te incorporated in the medium, b egonia tissue accum ulated significantly more silicon when a drench of soluble potassium silicate (AgSil25) was applied as a source of silicon in the growing medium compared to control plants and plants amended with Excellerator or Wollastonite in both experiments. The silic on concentration of the tissue on a dry weight basis was 2.6 and 2.4 fold higher in AgSil25 treated plants compared to that of control plants for the two experiments, respectively. In the first experiment (Table 2 3) plants amended with Excellerator and Wo llastonite had a lower numerical silicon concentration than control plants, while there was no statistically significant difference between these treatments in the second experiment. The medium amended with AgSil25 has a pH of 8.69 at the end of the experi ment, which is significantly higher than that of medium amended with Excellerator or Wollastonite The pH of all th e silicon amendment treatments wa s higher than that of the control. AgSil25 amended medium also had a higher EC than silicon amended media. M ost remarkably, the dry weight of AgSil25 amended plants was less than 20% of the dry weight of control plants in both

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35 experiments (Table 2 4). AgSil25 amended plants were very small compared to the other plants (Figure 2 4 ), which is also obvious from the dry weight measurements (Tables 2 3 and 2 4). Impatiens Impatiens Super Elfin White (Speedling, Sun City, FL) was grown using Wollastonite at 0, 0.47, 0.94, and 1.87 kg elemental s i licon / m 3 in the greenhouse. The silicon concentration in the dried tissue was determined after 4 weeks of growth (Table 2 5). No significant difference was found between any of the treatments. Silicon treatment also had no effect on the dry weight of impatiens leaves. Regression analysis was performed with both a linear and a qu adratic model. In the linear model there was no statistical support for a slope different from zero (R 2 =0.1251 ), with an estimated intercept at 0.1909 With the quadratic model, a curve was fitted (R 2 =0.3013 ) s hown in Figure 2 5 with the formula: y = 0.1 111 + 0. 2676 x + 0.1424 Where y is the silicon concentration (cg/gm ) and x is the silicon amendment in kg elemental silicon per hectare. The estimated curve has a maximum silicon concentration of 0.30 at an amendment of 1.2 kg elemental silicon/ m 3 To con firm these results, impatiens was grown in medium amended with Wollastonite at 0 and 1.87 kg elemental s i licon / m 3 in 3 additional experiments. The differences in the silicon concentrations of the impatiens leaves were not statistically significant (Table 2 6). Dry weight of the leaves was significantly different in the third experiment, with Wollastonite amended p lants being 46% smaller than those of control plants. Comparing the three experiments, the dry weight and level of silicon accumulation of the pla nts in the first experiment was smaller than in the second and third experiments. To test whether alternative sources of silicon might result in significant silicon accumulation in impatiens, experiments were performed using AgSil25, Excellerator, and

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36 Woll astonite as silicon sources (Tables 2 7 and 2 8). In these experiments, impatiens Super Elfin Lipstick plants grown in medium amended with silicon were significantly smaller than the control plants, especially when amended with AgSil25 (Figure 2 6 panel D ). The pH and EC AgSil25 amended medium were significantly higher than that of control plants in both experiments. In the experiments where different sources of silicon were used (Tables 2 7 and 2 8), the cultivar of impatiens used was Super Elfin Lipstick and the silicon percentage of dry weight was higher than in the experiments where different amounts of Wollastonite were added (Tables 2 5 and 2 6) to the impatiens cultivar Super Elfin White. Although the silicon concentration of Wollastonite amended pl ants was 43% higher than that of control plants in the first experiment (Table 2 7), this difference was not statistically significant. By contrast, in the second experiment, the 24% increase in silicon concentration of Excellerator and Wollastonite amende d leaves compared to control leaves was statistically significant. Dry weights of Excellerator and Wollastonite amended plants were 45 and 36% smaller than control plants respectively in the first experiment (Table 2 7), while the dry weight of AgSil25 ame nded plants was 69% lower than that of control plants, and 43 and 52 % lower than that of Excellerator and Wollastonite amended plants. Smaller Excellerator and AgSil25 amended plants can be seen in Figure 2 6 panels C and D, which also shows that plants from both these treatments were also chlorotic. In the second experiment (Table 2 8) all the AgSil25 amended plants died, and the silicon concentration could not be analyzed for this treatment. The dry weight of the Excellerator and Wollastonite amended pl ants was no different from that of the control plants.

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37 Marigold Marigold plants were grown for 4 weeks in 100 mm pots (Kord Products, Toronto, Ontario, Canada) under greenhouse conditions in growing medium amended with the equivalent of 0, 0.94 and 1.87 k g elemental s i licon / m 3 As shown in Table 2 9, there was no statistically significant differ ence in silicon concentration in the leaves among the different silicon levels There was no difference between the dry weight of leaves from silicon amended and co ntrol plants. Regression was performed for a linear and a quadratic model. A linear model resulted in a slope not significantly different from zero, and an intercept of 0.204 (R 2 =0.175 6). The quadratic model also predicted parameters not significantly diff erent from zero, with an estimated intercept at 0.215 (R 2 =0.2791, shown in Figure 2 7). This exp eriment was repeated twice with only levels of 0 and 1.87 kg elemental silicon/m 3 The results are listed in Table 2 10. In the first experiment, there was no s ignificant difference between silicon amended and control plants, and no difference in silicon concentration In the second experiment, dry weight of leaves from plants amended with Wollastonite was 25% lower than control leaves. There was no difference in the silicon concentration of leaves amended with silicon compared to the control. In contrast to the results in Table 2 9, the silicon concentration of leaves grown with amendment levels of 1.87 kg elemental silicon/ m 3 was not significantly lower than con trol plants, and was similar in both experiments. Alternative sources of silicon were tested in two experiments to test whether different silicon sources might result in silicon accumulation in marigold. AgSil25, Excellerator and Wollastonite were all appl ied at a rate equivalent to 1.40 kg elemental silicon/m 3 In both experiments (Table 2 11 and Table 2 12), AgSil25 amended pots had very high pH (means of 8.87 and 9.03).

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38 In the first experiment (Table 2 11) only one plant amended with AgSil25 survived, an d it remained very small (Figure 2 8 ). The dry weights of AgSil25, Excellerator, and Wollastonite amended leaves were 51%, 44%, and 44% less than that of control plants. The silicon concentration of plants grown in medium amended with Excellerator and Woll astonite in the first experiment (Table 2 11) was actually lower than that of the control plants, except for the single plant grown on medium amended with AgSil25, which survived and had a higher silicon concentration than both the control and Excellerator and Wollastonite amended plants. In the second experiment (Table 2 12) none of the AgSil25 amended plants survived, and thus no silicon concentration could be determined for these plants. No statistic ally significant differences were found in the dry weig ht of leaves from control plants compared to the silicon amended plants, and similarly, no difference was found in the silicon concentration of the leaves. Tigergrass Accumulation of silicon was tested in tigergrass using the equivalent of 0, 0.47 0.94 a nd 1.87 kg elemental silicon/m 3 added to the growing medium The experiment was repeated twice, results are reported in Tables 2 13 and 2 14, and the rate r esponse curves are in Figure 2 9 and 2 10 respectively. There was a statistically significant uptake of silicon for the different rates of silicon applied in both experiments. The dry weight of plants amended with 1.87 kg elemental s i licon / m 3 was lower than control plants in both experiments. The silicon concentration of tigergrass amended with 1.87 kg e lemental s i licon / m 3 is 2.5 fold greater than the silicon concentration of control plants in the first experiment, and 2.9 fold greater in the second experiment. Linear and quadratic regression analysis was performed for both experiments. For the first expe riment, linear re gression estimated a slope of 0.2553, and an intercept of 0.4030 (R 2 =0.7244 ). The quadratic model was a better fit than the linear model (R 2 =0.79 9 0 ), with a

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39 maximum of 0.84% at an amendment rate of 1.81 kg elemental silicon/ m 3 (Figure 2 9) The formula with estimated parameters is: y= .1527 x 2 + 0. 5520 x + 0.3395 In this formula y is silicon concentration (% cg/gm ) and x is the si licon amendment (kg elemental silicon / m 3 ). In the second experiment, the linear model estimated a slope of 0. 57 52, and an intercept of 0.6653 (R 2 =0.9016 ), but the quadratic model was again a better fit (R 2 =0.9438). This model estimated the maximum silicon concentration at 1.71 cg/gm at a silicon amendment of 2.3 0 kg elemental s i licon / m 3 The corresponding formula i s: y= 0.2139 x 2 + 0. 9861 x + 0.5720 Different sources of silicon were tested for their effect on tigergrass silicon concentration AgSil25, Excellerator, and Wollastonite were used at rates equivalent to 1.40 kg elemental s i licon / m 3 This experiment was pe rformed only once and the results are listed in Table 2 15. Plants amended with Excellerator and Wollastonite had 4.9 and 4.4 times the percent silicon relative to control plants. Plants amended with AgSil25 had 2.1 times the amount of silicon as control p lants, but this difference was not significant (Table 2 15) There was no significant difference in the dry weight of the plants from the different treatments. Discussion According to the definition of silicon non accumulators by Ma et al. (2001 b ) begonia is not an accumulator of silicon. The level of silicon as a percentage of dry weight varied between experiments, but was typically between 0.2 and 0.3 cg/gm and did not exceed 0.4 cg/gm when silicon was incorporated in the medium as Excellerator or Wolla stonite. In the experiment performed with different rates of silicon amendment, regression analysis did not support a linear or quadratic curve with parameters different from zero, so there was no rate response. A hig her silicon concentration (0.82 cg/gm a nd 0.89 cg/gm for the two experiments) was noted when

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40 soluble potassium silicate (AgSil25) was applied as a drench. However, plants treated with AgSil25 performed very poorly, grew very li ttle, and often died (Figure 2 4 ). Amendment with AgSil25 increased the pH to 8.86 and 8.69 in the two experiments, which may cause serious micronutrient deficiencies. In addition, the EC was very high. A likely cause is the failure of the plants to grow, as a result of which the plants did not take up nutrients from the m edium. These nutrients then accumulated over the course of the experiment These results indicate that the criteria used to categorize silicon accumulators apart from non accumulators need to be placed in the context of a marketable plant. Clearly, AgSil 25 as applied in this study does not result in a marketable plant. Because AgSil2 5 i s a liquid source of soluble silicon is immediately available to the plant, as opposed to the granular forms of silicon amendment (Excellerator and Wollastonite), it might be possible to apply less AgSil25 to the pots, lim iting the increase in pH. This could shed light on begonias ability to uptake silicon. Under the conditions of the experiments described in this study, amendment of soilless medium with silicon does not re sult in a statistically significant increase in the silicon concentration of begonia. The use of AgSil25 as described in this study cannot be recommended to ornamental plant growers as it results in too high a pH to be of practical use. Impatiens Super El fin White grown on soilless medium amended with Wollastonite at rates of 0 to 1.87 kg elemental silicon/ m 3 did not accumulate silicon, even though silicon concentration was 1.8 2 times the amount in control plants. Regression using a linear and a quadrati c model, resulted in a better fit for a quadratic curve, weakly supporting the hypothesis thatimpatiens had a rate response to silicon amendment. In subsequent experiments comparing amendments of 0 and 1.87 kg elemental s i licon / m 3 the numerical differenc e between the

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41 treatment means was much smaller. Using different sources of silicon for the soil amendment at a rate equivalent to 1.40 kg elemental silicon/ m 3 higher levels of silicon in plant tissue were measured. Plants grown in medium amended with AgSi l25, Excellerator, and Wollastonite had 63%, 14%, and 43% more silicon than the control, respectively, in the first experiment but these differences were not statistically significant. In the second experiment, however, Excellerator and Wollastonite amende d impatiens Super Elfin Lipstick had 24% more silicon on a dry weight basis than control plants, and this difference was statistically significant. Although most of the experiments carried out in this study showed no statistically significant difference s it can not be ruled out that impatiens accumulate s silicon. Possibly, experiments with a larger number of replicates might result in more consistent results. Frantz et al. (2005) reported that New Guinea impatiens (cv. Pure Beauty Purple) grown in soill ess medium amended with 2.0 mM potassium silicate were stiffer to the touch, and had sharper serrated edges than control plants that did not receive potassium silicate. When the leaves were analyzed with scanning electron microscopy and energy dispersive X ray analysis, they were found to have silicon scales on the serrated edges possibly located near hydathodes. The percentage of silicon as a percentage of dry weight was not reported in that study. It is possible that impatiens accumulate s silicon, but t he amount was so small that it wa s not (consistently) measurable under the conditions used in this study. Another possibility, which was observed for all three ornamentals in this study, is that these plants need very small amounts of s ilicon and that enou gh silicon wa s supplied with the soilless medium and/or irrigation water that additional silicon amendment does not result in an increase in silicon concentration It is extremely difficult to keep experiments silicon free (Epstein 1994, 1999), since uncha rged silicic acid passes through ion exchangers; even de ionized water has some silicon (Epstein 1999).

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42 As with begonia, AgSil25 wa s not likely to be a practical source of silicon for impatie n s under the conditions used in this experiment. Plants typically remained very small (Figure 2 6 panel D), and often died; those that were alive were chlorotic. Impatiens appears to be more sensitive to increases in pH than begonia. Begonia did not show obvious changes in appearance or chlorosis when the medium was am end ed with Excellerator (Figure 2 4 panel C) while impatiens did (Figure 2 6 panel C). Both plant species showed decreased growth and chlorosis when the medium was amended with AgSil25. When marigold was grown in soilless medium amend ed with Wollastonite at rates from 0 to 1.87 kg elemental silicon/ m 3 plants amended with 0.94 and 1.87 kg elemental silicon/ m 3 actually had lower amounts of silicon per dry weight in the leaves, but the difference was not statistically significant. There was no rate response in marigold, since no slope estimated with linear regression differed significantly from zero In two separate experiments where Wollastonite was applied at rates equivalent to 0 and 1.87 kg elemental s i licon / m 3 the amount of silicon as a percentage of d ry weight was similar for both treatments and experiments (Table 2 10), with levels of 0. 22 and 0. 23 cg/gm silicon. Using different sources of silicon for medium amendment, the mean pH of pots amended with AgSil25 was as high as 8.87 and 9.03 in two experi ments (Table 2 12 and 2 12). At a pH greater than 9, silicic acid (Si(OH) 4 ) disassociates into silicate ion ((OH) 3 (SiO 1 ) and becomes unavailable to the plant. As with begonia and impatiens, using AgSil25 under the conditions described in this study is imp ractical, but it might be possible to lower the concentration of potassium silicate applied in the form of AgSil25 to decrease the pH and still measure a difference in silicon concentration

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43 F or begonia and marigold amendment of the soilless growing mediu m with Wollastonite and Excellerator does not result in increased silicon concentration of the leaf tissue. It is possible that different results can be obtained with AgSil25 if the application rate is changed. There is weak support for impatiens accumulat ing silicon in a rate dependent manner, following a quadratic relationship. Future research could implement strategies to maintain a better pH balance for all silicon amended treatments as was done by adding HNO 3 and decreasing KNO 3 by Voogt and Sonneveld (2001) and by adding H 2 SO 4 by Frantz et al. (2005), although it is questionable whether that would be practical from a growers point of view. It is possible that there are differences in silicon uptake from one cultivar to another. Neither Super Elfin Whi te impatiens nor Super Elfin Lipstick impatiens showed significant difference in silicon uptake, but the latter did have higher levels of silicon that the Super Elfin White. In addition, since disease susceptibility of the plants used in this study was not tested, it cannot be ruled out that plants that do not have measurable increases in silicon concentration benefit from silicon amendment of the growing medium From the examples seen in this study it is clear that such a process would require re designing the fertilization to offset the increase in pH caused by silicates. Another possibility is that the ornamental plants used in this study do not accumulate silicon to a level significantly different from that of control plants, while still benefiting from the amendment in terms of increased disease resistance According to the criteria used by Ma et al. (2001 b ), sunflower would not be considered an accumulator, but Kamenidou et al. (2008) did determine that the level of silicon in silicon amended plants was statistically higher than that of control plants, and that silicon amended sunflowers were taller than control plants. In addition, when the medium was amended with soluble silicon (potassium silicate), the plants were shorter,

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44 had a smaller flower diamet er, and deformed flowers, indicating that potassium silicate is not a practical way of amending the medium for sunflowers. In zinnia silicon amendment resulted in a delayed powdery mildew symptom development (Locke et al. 2006). This means that it is poss ible for plants to benefit from silicon even if it is not considered an accumulator based on the silicon concentration of the plants tissue. The ornamental grass tigergrass, accumulated silicon and generated a silicon rate response curve similar those seen for turfgrasses ( Datnoff et al. 2007; Datnoff and Nagata 1999; Datnoff and Rutherford 2 003; Nanayakkara et al. 2008ab ). In both experiments, the rate response curve fit a quadratic model. Since tigergrass belongs to the family Poaceae, this is no surprise With regard to the different sources of silicon used, Excellerator and Wollastonite result ed in higher levels of silicon in the leaves compared to leaves of control and AgSil25 amended plants. No significant differences in mean dry weight were seen betwe en the silicon amended plants and the control plants, not even for AgSil25, indicating that tigergrass can better tolerate AgSil25 and a high medium pH than the ornamental dicotyledons used in this study. In conclusion, begonia and marigold did not accumul ate silicon, while there was weak statistical support for silicon accumulation in impatiens. Tigergrass accumulated silicon in a rate dependent manner, and was used in subsequent experiments to test the hypothesis that silicon accumulation caused an increa se in resistance against a fungal pathogen.

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45 Table 2 1 Effect of silicon rate on percent dry wei ght accumulation of silicon in b egonia S i ( % c g / g m ) x S i l i c o n a m e n d m e n t ( k g e l e m e n t a l s i l i c o n / m 3 ) L e a v e s S t e m s 0 0 1 3 a y 0 1 5 a 0 9 4 0 1 4 a 0 2 1 a 1 8 7 0 1 8 a 0 1 7 a x S i l i c o n c o n c e n t r a t i o n o f B e g o n i a s p l e a v e s a n d s t e m s a s a p e r c e n t a g e o f d r y w e i g h t y M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 ) Table 2 2 Dry weight and s i licon c oncentration of b egonia leaves grown at 0 and 1.87 kg elemental silicon/ m 3 E x p e r i m e n t 1 E x p e r i m e n t 2 A m e n d m e n t ( k g e l e m e n t a l s i l i c o n / m 3 ) L e a f d r y w e i g h t ( g m ) S i ( c g / g m ) x L e a f d r y w e i g h t ( g m ) S i ( c g / g m ) x 0 0 9 0 a y 0 3 9 a 0 7 7 a 0 2 9 a 1 8 7 0 5 2 a 0 4 8 a 0 5 2 a 0 2 2 a x S i l i c o n c o n c e n t r a t i o n o f B e g o n i a s p l e a v e s a s a p e r c e n t a g e o f d r y w e i g h t y M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 ) Table 2 3 Effect of different silicon sou rces applied at a rate of 1.40 kg elemental silicon/ m 3 on growing medium pH, EC, and b egonia dry weight and silicon concentration (first experiment) T r e a t m e n t p H E C ( m S / c m ) L e a f d r y w e i g h t ( g m ) S i ( c g / g m ) x C o n t r o l 6 3 5 c y 1 9 5 b 0 4 1 a 0 3 2 b A g S i l 2 5 8 8 6 a 4 8 1 a 0 1 2 b 0 8 2 a E x c e l l e r a t o r 7 8 9 b 2 7 5 b 0 3 4 a 0 1 9 c W o l l a s t o n i t e 7 6 0 b 2 0 2 b 0 4 1 a 0 2 2 c x S i l i c o n c o n c e n t r a t i o n o f B e g o n i a s p l e a v e s a s a p e r c e n t a g e o f d r y w e i g h t y M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 ) Table 2 4 Effect of different silicon sources applied at a rate of 1.4 0 kg elemental silicon/ m 3 on growing medium pH, EC, and b egonia dry weight and silicon concentration (second experiment) T r e a t m e n t p H E C ( m S / c m ) L e a f d r y w e i g h t ( g m ) S i ( c g / g m ) x C o n t r o l 5 8 5 c 2 0 1 b 0 8 7 a 0 3 7 b A g S i l 2 5 8 6 9 a 3 8 6 a 0 1 7 b 0 8 9 a E x c e l l e r a t o r 7 5 3 b 1 9 8 b 0 6 3 a 0 4 0 b W o l l a s t o n i t e 7 4 6 b 1 7 7 b 0 7 8 a 0 3 3 b x S i l i c o n c o n c e n t r a t i o n o f B e g o n i a s p l e a v e s a s a p e r c e n t a g e o f d r y w e i g h t y M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 )

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46 Table 2 5 Silicon concentration of impatiens leaves grown in medium amended with different levels of Wollas tonite T r e a t m e n t ( k g e l e m e n t a l s i l i c o n / m 3 ) p H E C ( m S / c m ) L e a f d r y w e i g h t ( g m ) S i ( c g / g m ) x 0 5 6 b y 1 8 3 a b 0 6 1 a 0 1 4 a 0 4 7 6 9 a 1 6 7 b 0 6 0 a 0 2 6 a 0 9 4 7 1 a 2 0 9 a 0 5 6 a 0 2 8 a 1 8 7 7 2 a 1 6 6 b 0 5 5 a 0 2 6 a x S i l i c o n c o n c e n t r a t i o n o f I m p a t i e n s s p l e a v e s a s a p e r c e n t a g e o f d r y w e i g h t y M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 ) Table 2 6 Silicon concentration of impatiens leaves grown at 0 and 1.87 kg elemental sili con/ m 3 E x p e r i m e n t 1 E x p e r i m e n t 2 E x p e r i m e n t 3 A m e n d m e n t ( k g e l e m e n t a l s i l i c o n / m 3 ) D r y w e i g h t ( g m ) S i ( % ) x D r y w e i g h t ( g m ) S i ( c g / g m ) D r y W e i g h t ( g m ) S i ( c g / g m ) 0 0 5 4 a y 0 1 4 a 1 0 a 0 2 7 a 1 3 a 0 2 7 a 1 8 7 0 5 7 a 0 1 5 a 0 9 a 0 2 4 a 0 7 b 0 2 6 a x S i l i c o n c o n c e n t r a t i o n o f I m p a t i e n s s p l e a v e s a s a p e r c e n t a g e o f d r y w e i g h t y M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 ) Table 2 7 Silicon concentration in impatiens grown in mediu m amended with different sources of silicon at a rate of 1.40 kg elemental silicon / m 3 (first experiment) T r e a t m e n t p H E C ( m S / c m ) L e a f d r y w e i g h t ( g m ) S i ( c g / g m ) x C o n t r o l 6 2 c y 1 7 8 c 0 4 2 a b 0 4 2 a A g S i l 2 5 8 8 a 4 1 5 a 0 1 3 c 0 5 7 a E x c e l l e r a t o r 8 1 b 2 4 8 b 0 2 3 b c 0 4 8 a W o l l a s t o n i t e 7 8 b 2 2 1 b c 0 2 7 a b 0 6 0 a x S i l i c o n c o n c e n t r a t i o n o f I m p a t i e n s s p l e a v e s a s a p e r c e n t a g e o f d r y w e i g h t y M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 ) Table 2 8 Silicon concentration in impatiens grown in medium amended with different sources of silicon at a rate of 1.40 k g elemental silicon / m 3 (second experiment) T r e a t m e n t p H E C ( m S / c m ) L e a f d r y w e i g h t ( g m ) S i ( c g / g m ) x C o n t r o l 6 0 c y 2 1 7 b 0 4 5 a 0 4 6 b A g S i l 2 5 8 0 a 3 2 0 a n o t d o n e z n o t d o n e z E x c e l l e r a t o r 7 5 b 2 3 5 b 0 3 8 a 0 5 7 a W o l l a s t o n i t e 7 3 b 2 3 4 b 0 3 9 a 0 5 7 a x S i l i c o n c o n c e n t r a t i o n o f I m p a t i e n s s p l e a v e s a s a p e r c e n t a g e o f d r y w e i g h t y M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 ) z A l l p l a n t s t r e a t e d w i t h A g S i l 2 5 d i e d i n t h i s e x p e r i m e n t

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47 Table 2 9 Silicon concentration in the leaves of marigold grown in pots amended with different levels of silicon a pplied as Wollastonite T r e a t m e n t ( k g e l e m e n t a l s i l i c o n / m 3 ) p H E C ( m S / c m ) L e a f d r y w e i g h t ( g m ) S i ( c g / g m ) x 0 6 8 a y 1 7 4 a 0 4 5 a 0 2 1 a 0 9 4 7 0 a 1 6 8 a 0 4 5 a 0 1 5 a 1 8 7 6 9 a 2 4 0 a 0 4 8 a 0 1 6 a x S i l i c o n c o n c e n t r a t i o n o f T a g e t e s s p l e a v e s a s a p e r c e n t a g e o f d r y w e i g h t y M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 ) Table 2 10 Dry weight and s ilicon concentration of marigold leaves gr own at 0 and 1.87 kg elemental silicon / m 3 E x p e r i m e n t 1 E x p e r i m e n t 2 A m e n d m e n t ( k g e l e m e n t a l s i l i c o n / m 3 ) L e a f d r y w e i g h t ( g m ) S i ( c g / g m ) x L e a f d r y w e i g h t ( g m ) S i ( c g / g m ) x 0 1 9 4 a y 0 2 2 a 2 0 6 a 0 2 3 a 1 8 7 1 6 4 a 0 2 3 a 1 5 4 b 0 2 2 a x S i l i c o n c o n c e n t r a t i o n o f T a g e t e s s p l e a v e s a s a p e r c e n t a g e o f d r y w e i g h t y M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 ) Table 2 11 Silicon concentration of marigold amended with different sources of silicon applied at 1.40 kg element al silicon / m 3 (first experiment) T r e a t m e n t p H E C ( m S / c m ) L e a f d r y w e i g h t ( g m ) S i ( c g / g m ) x C o n t r o l 6 4 d y 1 8 5 a 0 4 1 a 0 2 0 b A g S i l 2 5 8 9 a 5 5 1 b 0 2 0 b 0 2 9 a E x c e l l e r a t o r 8 1 b 1 7 1 a 0 2 3 b 0 1 7 b c W o l l a s t o n i t e 7 8 c 2 1 9 a 0 2 3 b 0 1 2 c x S i l i c o n c o n c e n t r a t i o n o f T a g e t e s s p l e a v e s a s a p e r c e n t a g e o f d r y w e i g h t y M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 ) Table 2 12 Silicon concentration of leaf tissue of marigold amende d with different sources of silicon applied at 1.40 kg s i licon / m 3 (second experiment) T r e a t m e n t p H E C ( m S / c m ) L e a f d r y w e i g h t ( g m ) S i ( c g / g m ) x C o n t r o l 6 0 c 1 9 7 b 0 3 7 a 0 2 8 a A g S i l 2 5 9 0 a 2 6 3 a E x c e l l e r a t o r 7 3 b 2 1 5 a b 0 2 6 a 0 3 0 a W o l l a s t o n i t e 7 2 b 1 7 1 b 0 3 3 a 0 2 8 a x S i l i c o n c o n c e n t r a t i o n o f T a g e t e s s p l e a v e s a s a p e r c e n t a g e o f d r y w e i g h t y M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 )

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48 Table 2 13 Silicon con centration of tigergrass leaves for different levels of medium amendment with Wollastonite (first experiment) T r e a t m e n t ( k g e l e m e n t a l s i l i c o n / m 3 ) p H E C ( m S / c m ) D r y w e i g h t ( g m ) S i ( c g / g m ) x 0 6 2 b y 2 0 2 a b 2 9 2 a 0 3 4 c 0 4 7 6 8 a b 1 2 2 a b 2 7 8 a b 0 5 5 b 0 9 4 7 0 a 2 6 4 a 2 1 6 a b 0 7 4 a b 1 8 7 7 2 a 2 6 4 a 1 7 8 b 0 8 4 a x S i l i c o n c o n c e n t r a t i o n o f t i g e r g r a s s l e a v e s a s a p e r c e n t a g e o f d r y w e i g h t y M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 ) Table 2 14 Silicon concentration of tigergrass leaves for different levels of medium amendment with Wollastonite (second experiment) T r e a t m e n t ( k g e l e m e n t a l s i l i c o n / m 3 ) p H E C ( m S / c m ) D r y w e i g h t ( g m ) S i ( c g / g m ) x 0 6 0 c 2 1 0 a 2 3 a b 0 5 7 d 0 4 7 6 3 b 2 1 0 a 2 6 a b 1 0 4 c 0 9 4 6 4 b 1 9 0 a 2 9 a 1 3 2 b 1 8 7 7 3 a 1 9 3 a 1 4 b 1 6 7 a x S i l i c o n c o n c e n t r a t i o n o f t i g e r g r a s s l e a v e s a s a p e r c e n t a g e o f d r y w e i g h t y M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 ) Table 2 15 Silicon accumulation of tigergrass grown with different sources of silicon at a rate equivalent to 1.40 kg elemental silicon/ m 3 T r e a t m e n t p H E C ( m S / c m ) D r y w e i g h t ( g m ) S i ( c g / g m ) x C o n t r o l 6 0 b y 1 4 9 b 0 5 0 a 0 2 2 b A g S i l 2 5 7 0 0 a 2 8 9 a 0 4 8 a 0 4 7 b E x c e l l e r a t o r 7 2 a 1 7 0 b 0 6 9 a 0 9 6 a W o l l a s t o n i t e 6 6 a 1 9 7 b 0 6 9 a 1 0 8 a x S i l i c o n c o n c e n t r a t i o n o f t i g e r g r a s s l e a v e s a s a p e r c e n t a g e o f d r y w e i g h t y M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 )

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49 Figure 2 1 Experimental setup for m arigold s in the greenhouse.

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50 Figure 2 2 Experimental setup of b egonia, marigold, and impatiens containers in the climate controlled growth room with fluorescent lighting

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51 Figure 2 3 Silicon concentration of b egonia leaves and stems after four weeks of growth on different levels of silicon amendment. The solid line s represent the regression curv e s y= 0.0232 x + 0.13 ( P=0.2775, R 2 =0.0997 n = 5 ) for leaves and y= $ 0.0529 x 2 + 0.106 x + 0.1549 for stems ( P=0.7595, R 2 =0. 1262 n= 5 ) The blue triangles represent the mean s ilicon concentration of stems and the red squares represent the mean silicon concentration of leaves

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52 Figure 2 4 Begoni a plants treated with different sources of silicon after four weeks of growth A. Non amended control, B. Wollastonite, C. Excellerator, D. AgSil25.

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53 Figure 2 5 Silicon concentration of impatiens leaves and stems after four weeks of growth on different levels of silicon amendment. The soli d line represents the regression cur v e y= 0.1111 x 2 + 0.2676 x + 0 .1424 ( P=0.0475, R 2 =0.3013 n=5 ) The blue squares represent the mean silicon concent ration of impatiens leaves

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54 Figure 2 6 Impatiens plants amended with different sources of silicon after four weeks of growth A. Non amended control, B. Wollastonite, C. Excellerator, D. AgSil25.

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55 Figure 2 7 Silicon concentration of marigold leaves after four weeks of growth on different level s of silicon amendment. The soli d line represents the regression curve y= 0.0392 x 2 0.1008 x + 0.215 ( P=0.1403, R 2 =0.2791 n= 5 ) The blue squares represent the mean silicon concen tration of marigold leaves

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56 Figure 2 8 Marigold plants amended with different sources of silic on after four weeks of growth A. Non amended control, B. Wollastonite, C. Excellerator, D. AgSil25.

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57 Figur e 2 9 Rate dependent silicon accumulation of tigergrass ( first experiment). The soli d line represents the quadratic regression curve y= 0.1527 x 2 + 0.5519 x + 0.3 395 ( P<0.0001, R 2 =0.79 9 0 n=5 ). The squares represent the mean silicon concentration of tigergrass

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58 Figure 2 10 Rate dependent silicon accumulation of tigergrass ( second experiment). The soli d line represents the quadratic regression curve y= 0.2139 x 2 + 0.9861 x + 0.5719 ( P<0.0001, R 2 =0.9438 n= 5 ). The blue squares represent the mean sili con concentration of tigergrass

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59 CHAPTER 3 EFFECT OF SILICON ON TIGERGRASS DISEASE RESISTANCE AGAINST TIGERGRASS LEAF SPOT Introduction Exserohi lum rostratum Exserohilum rostratum (Drechsler) Leonard & Suggs (Leonard and Suggs 1974) is the anamorph of Setosphaeria rostrata Leonard (Leonard 1976) Sivanesan lists the following synonyms: Helminthosporium halodes Drechsler Helminthosporium rostratum D rechsler Helminthosporium halodes Drechsler var. tritici Mitra Helminthosporium halodes Drechsler var. elaeidicola Kovachich Bipolaris halodes (Drechsler) Shoem. Bipolaris rostrata (Drechsler) Shoem. Drechslera halodes (Drechsler) Subram. & Jain Helminthos porium apatternae K.S. Deshpande & K.B. Deshpande Drechslera rostrata (Drechsler) Richardson & Fraser Exserohilum halodes (Drechsler) Lenard & Suggs Luttrellia rostrata (Drechsler) Gonorsta Drechsler (1923) initially described two distinct species. E. rostratum and E. halodes ; the E. rostratum conidia were more rostrate and larger, while the E. halodes conidia were elliptical and smaller. These differences were not con sistent over time, and often conidia of the two species were indistinguishable. Honda and Aragaki (1978a) found that temperature affected conidial morphology, with lower temperatures resulting in longer conidia. Leonard (1976) suggested that E. halodes was synonymous with E. rostratum and described the conidia as follows: Conidia porogenous, acrogenous becoming pseudopleurogenous, elliptical or narrowly obclavate rostrate, brown or olivaceous, thick walled except in a small subhyaline region at the apex a nd a similar region surrounding the hilum which protrudes as a darkened cylinder or truncate cone from the end of the basal cell. Conidia usually straight, 1 to 15 septate (rarely more), the basal septum darker and thicker than intermediate septa, 15 190 (rarely more) 7 29 m, germ tubes produced from subhyaline region of end cells and

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60 growing parallel to conidial axis. Conidiophores cylindrical, simple, olivaceous brown, 40 180 m, 1 to 6 spetate, with conidia produced on geniculations at intervals of 5 30 m. The teleomorph is heterothallic, and matings were more successful when the cultures were preconditioned by growth at low temperatures (4 C) before mating opposite mating types on a sterilized substrate (barley grains or pieces of Johnson grass; L eonard 1976). The original genus Helminthosporium was divided in two subgenera: Eu Helminthosporium with fusoid conidia that only germinated from the terminal cells, and Cylindro Helminthosporium with cylindrical multiseptate conidia tha t could germinate f rom any cell (Drechsler 1923). The subgenus Cylindro Helminthosporium members of which were often associated with Pyrenophora teleomorphs, beca me the genus Drechslera Ito (Sivanesan 1987). Shoemaker proposed the genus name Bipolaris for Eu Helminthosporiu m which was often associated with Cochliobolus teleomorphs, especially if the conidia did not have a protuberant hilum (Sivanesan 1987). Only one species of Bipolaris with a protuberant hilum, Bipolaris turcica (Pass.), had a teleomorph stage associated w ith it, and it belonged to the genus Trichometasphaeria Munk (Luttrell 1958). More anamorphs belonging to different anamorph genera were identified with protuberant hila, and a Trichometasphaeria teleomorph. Disagreement about the taxonomy of species belon ging to the former Helminthosporium complex continued for some time (Sivanesan 1987). In 1974, Leonard and Suggs erected a new anamorph genus, Exserohilum for Bipolaris species that had a protruding hilum, and the associated teleomorph genus was called Se tosphaeria They included all species within the complex with a protruding hilum in the new genus Exserohilum The genera Bipolaris Exserohilum and Drechslera were associated with the teleomorph genera Cochliobolus Setosphaeria and Pyrenophora respec tively. It proved particularly important to note the temperature at which cultures were grown when observing

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61 protuberance of the hilum. Honda and Aragaki (1978b) found that the hilum of E. rostratum was at least partially inhibited at temperatures above 34 C, which could lead to misidentification. Exserohilum rostratum is common on grasses, occurs in soil, and is widely distributed worldwide (Kucharek 1973; Sivanesan 1987; Whitehead and Calvert 1959; Young et al. 1947). Whitehead and Calvert (1959) reported the fungus as the causal agent of ear rot of corn and leaf spot of thirteen different grasses, while Kucharek (1973) reportedly isolated it from rotted corn stalks in Florida in 1971 and confirmed it as the cause of the disease. Silicon in tigergrass Incr eased disease resistance in monocotyledons as a result of silicon application has been shown in numerous host pathogen systems. Rice rice blast ( Oryza sativa L. Magnaporthe grisea (T.T. Hebert) M.E. Barr) is the best studied system (Volk et al. 1958; Datn off et al. 1991; Seebold et al. 2000). Others include wheat powdery mildew ( Triticum aestivum L. Blumeria graminis f. sp. tritici ; Blanger et al. 2003), and barley powdery mildew ( Hordeum vulgare L. Erysiphe graminis D.C. Hordei ; Carver et al. 1987). Tige rgrass ( Thysanolaena maxima (Roxb.) Kuntze) accumulated silicon ranging from a concentration of 0.2 cg/gm dry weight when the growing medium was not amended with si licon up to a concentration of 1.6 cg silicon/ g m dry weight when the growing medium was amen ded with 1.8 7 kg elemental s i licon/m 3 The rate response fit a quadratic model, and wa s similar to those of turfgrasses for which silicon accumulation was demonstrated: bermudagrass (Datnoff and Rutherford 2003), perennial ryegrass (Nanayakkara et al. 2008 a,b), and St. Augustinegrass (Brecht et al. 2004, 2007 a ; Datnoff and Nagata 1999). In each of those case s, the increased silicon concentration of silicon amended turfgrass correlated with disease suppression of leaf spot and melting out on bermudagrass, gr ay leaf spot on both perennial ryegrass and St. Augustinegrass. These results also pr ovided evidence that silicon related disease resistance is not

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62 solely limited to diseases caused by biotrophs, such as the cereal powdery mildew examples mentioned above. Tigergrass is a commercial containerized and landscape ornamental grass from the family Poaceae similar in appearance to bamboo (Saikia 1992). In the summer of 2006, a leaf spot was first noticed in a South Florida nursery, and the disease has since then b een observed in several nurseries and la ndscapes throughout Miami Dade C ounty and the Florida Keys in Monroe County (A. Palmateer, personal communication ) In addition, the same leaf spot symptoms were observed on young transplants from a production greenh ouse In experiments reported in Chapter 2 silicon concen tration in tigergrass was determined to increase with silico n amendment. The goal of the research reported in this chapter was to 1) characterize the pathogen that was responsible for the leaf spot symptoms on tigergrass 2) determine whether silicon had a direct ef fect on pathogen growth, and 3) test whether silicon amendment increased tigergrass resistance to a fungal pathogen. Materials and Methods Pathogen Characterization Tigergrass plants were donated for research by Agristarts III, located in Apopka, Florida. Tigergrass leaf pieces each containing part of a lesion were excised with a small amount of surrounding asymptomatic tissue, surface st erilized for 45 seconds in 50 ml 10% commercial NaOC l solution ( Clorox C lorox Company Oakland, CA ) with a drop of detergent ( Tween 20 ) and rinsed three times in sterile de ionized water. The leaf pieces were picked up with sterile tweezers, excess surface water removed by briefly placing on filter paper (Whatman #1) and placed in the center of V8 juice agar plates. V8 juice agar was prepared by mixing 1 can (330 mL) V8 juice (Campbell Soup Company, Camden, NJ), 670 mL de ionized water, 3 mg calcium carbonate, and 15 20 gram agar, and autoclaving. Single spore isolates were obtained by

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63 transferring individual germinating conidia to fresh plates of V8 juice agar media. Cultures were maintained in an incubator at 21.1 26.3 C, with fl uorescent lighting at 970 lux, 12 hours light, 12 hours dark. Tentative ide ntification was done using Sivanesans dichotomous key (Sivanesan 198 7) based on conidial morphology. Kochs postulates were performed by gro wing single spore isolates on V8 juice agar medium, harvesting conidia from 7 10 day old cultures, re suspending t he conidia in sterile water with Tween 20 to varying inoculum densities of 10 3 to 10 5 c onidia/ml and spraying onto symptomless t igergrass plants with a Crown #8211 Spr tool (Gardnerville, NV). Inoculated plants were placed in plastic bags for 24 hours after inoculation to maintain high humidity and kept at in an air conditioned greenhouse (temperatures ranged from 22 32 C.) For c onfirmation of species identity polymerase chain reaction was performed with the MyCycler thermal cycler (Bio Rad laboratories, Hercules, CA) using Internal Transcribed Spacer region primers, ITS1 and ITS4 (Lott et al. 1993 ) with genomic fungal DNA isol ated with the Extract % n Amp kit (Sigma Aldrich). PCR products were cleaned with the QIAquick PCR purification kit (Qiagen), and sequenced by the ICBR sequencing core at the University of Florida. BLAST (Altschul et al. 1990 ) searches were performed, and sequence s were aligned with Clustal W (Larkin et al. 2007). To visualize conidia in the process of infecting tigergrass leaves, leaf sections with clearly visible lesions were cleared by heating (but not boiling) for 5 10 minutes in lactophenol blue, rinse d briefly in lactophenol essentially as described by Dhingra and Sinclair (1995). E xcess lactophenol was then removed by placing the leaf sections on a paper towel for a few seconds. Slides were prepared with lactophenol, and lesions were photographed usin g an Olympus BX51 bifocal microscope (Olympus, Japan) with an Olympus DP12 digital camera (Olympus, Japan).

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64 Conidial size was determi ned by measuring the width and length of 50 conidia derived from several isolates using an the bifocal microscope at a 400 fold magnification Fungal Grow th on Soluble Silicon The effect of soluble silicon on growth of the fungal pathogen in vitro was assessed by placing plugs of mycelium obtained with a # 1 hole punch (4 mm) from a 3 4 day old culture of a single spore isolat e on V8 juice agar plates containing 0, 1, 2, 4, and 8 ml AgSil per 100 ml V8 juice agar, which corresponded to 0, 34, 69 139, and 277 mM elemental silicon, respectively To prepare the media, AgSil25 was 1:1 diluted with de ionized water and filter st erilized using a 0.22 m vacuum driven disposable filtration system (Millipore Corporation, Billerica, MA). V8 juice agar was prepared by mixing 1 can (340 ml) V8 juice and 3 gm CaCO 3 per liter, and autoclaving. Diluted, filter sterilized AgSil25 and V8 ju ice agar were mixed before pouring into petri dishes to achieve the desired amounts of AgSil25 per 100 ml as previously mentioned. Since AgSil25 has a pH of 11.3, amending V8 juice agar with this product greatly affected the final pH of the medium. To asse ss the effect of pH on the growth of E. rostratum V8 juice agar plates also were amended with potassium hydroxide (KOH), which resulted in media with similar pH levels as AgSil25. Colony growth on each plate was measured by taking two measurements at 90 angles. Percent inhibition of growth (PIG) was calculated with the following formula: C = average diameter (cm) of colonies on control plates T = average diameter (cm) of colonies on the treatment plates

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65 At the end of the experiment, 9 days after transfe r, the mycelium was scraped off the medium, air dried for 3 4 days in sterile plastic petri dishes under the laminar airflow bench, pooled for each treatment, and analyzed for silicon concentration (to test whether the fungus had taken up silicon) using th e same technique used for determining silicon concentration in leaf tissue as described in the Materials and Methods section of Chapter 2 Digestion of fungal tissue only required a single autoclave induced digestion (compared to 4 6 cycles for leaf tissue ). Effect of Silicon on Disease Development Rate dependent silicon accumulation of tigergrass was reported in Chapter 2. To assess the effect of silicon on E. rostratum infection, tigergrass plants were grown for 4 weeks in 100 mm Azalea pots (Kord Product s, Toronto, Ontario, Canada). The treatments were, no amendment control, AgSil25, Excellerator, and Wollastonite at rates equivalent to 1.4 0 kg elemental s i licon / m 3 Amendments were included at the time of planting the tigergrass plugs, except for the trea tment with AgSil25, which was applied at time of planting and twice a week for the duration of the experiment (four weeks) Because the tigergrass arrived with leaf spot symptoms from the supplier, the tigergrass plugs were trimmed to the soilline and all owed to re grow. Growing medium was prepared by mixing a 19 liter bucket of Metro Mix (Sun Gro Horticulture Canada, Vancouver, British Columbia) or Fafard 4P Mix soilless medium (Fafard, Agawam, Massachussetts) with a 19 liter bucket of sand and 100 ml of Osmocote (Scotts, Marysville, Ohio). On the day of inoculation, one plant of each treatment was harvested to determine silicon con centration of the leaves. Three pots of each treatment containing plants of comparable size were selected for inoculation. Pl ants were kept on a NSF Shelf System (P rotrend Co., Taipei, Taiwan ), outfitted with fluorescent light bulbs and clear, heavy duty plastic sheeting 102 m thick (Contractors Choice, Olympic General Corporation, Reno, NV), and enclosed completely

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66 using Vel cro in order to maintai n a high relative humidity ( Figure 3 1). Plants were inoculated with conidia of E. rostratum ha rvested from 9 day old cultures. The conidial concentration was adjusted to 5 10 3 conidia/ml, and a drop of surfactant (Tween20) was ad ded to the conidial suspension. Tigergrass plants were inoculated with the conidial suspension using a Crown #821 1 Spr tool (Gardnerville, NV), by uniformly spraying the plants until runoff. The plants were placed in the enclosed humidity chamber (Figure 3 1). After 24 hours, the front plastic cover of the humidity chamber was removed. Plants were monitored for symp tom development and symptoms were scored using the Horsfall Barratt scale (Horsfall and Barratt 1945) every 24 hours up to 14 days. Two weeks after inoculation, the plants were harvested for determination of leaf silicon concentration The electrical condu ctivity ( EC ) of the pots was measured using the Field Scout Direct Soil EC probe (Spectrum Technologies, Inc., Plainfield, IL) one hour after the pots were watered with 1 gm/L Peters 20 20 20 At this time, 20 mL de ionized water was poured over the pots and the flow through was collected for pH measurement. The leaves were separated from the stems, dried for 2 3 days at 80 C in a dry heat oven (Isotemp Oven, Fisher Scientific) and ground finely using the Cyclotec 1093 sample mill (FOSS, Denmark). One h undred milligram of the ground tissue was weighed and placed in 100 ml plastic high speed polypropylene copolymer tubes (Nalgene) with loose fitting plastic caps for digestion. As a positive check, 100 mg of rice tissue was digested in the same manner as t he samples. Sodium hydroxide solution (100%) was added to each tube (3 ml) in the fume hood, 2 ml hydrogen peroxide were added to each tube. The tubes were then placed in to a 95 100 C water bath for one hour to initiate the digestion process, and to preven t spilling of undigested plant material during autoclaving. The tubes were placed into racks in the autoclave for a 20 minute liquid

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67 cycle, and allowed to cool to room temperature For the next round of autoclave induced digestion, 2 ml hydrogen peroxide w as added to each tube before autoclaving for 20 minutes as before. The digestion was repeated until the digested liquid became clear, and no leaf pie ces were visible The digestates were then diluted and silicon concentration determined using the colorimet ric method described in the Materials and Methods section of Chapter 2. Results Tigergrass plants often arrived with leaf spot symptoms (Figure 3 2) from the supplier Symptoms begin as small tan spots or flecks, which enlarged into tan colored lesions tha t elongated elliptically between the veins, sometimes with a yellow halo. Older lesions turned necrotic. Individual lesions in close proximity could coalesce into large necrotic elliptical spots to blotches, sometimes interspersed with chlorosis. Infected leaf tips turned light brown to brown, curled and turned yellow away from the leaf tip. All plants had to be cut back completely, to begin each experiment with healthy plants. This confirmed that the disease is a serious problem in the nursery, although du ring a discussion with the greenhouse manager of AgriStar tsIII, it became clear that it wa s not perceived as such (D. Hartman, personal communication ). A targeted or regular fungicide spray schedule of either Dithane (Mancozeb, Dow Agrosciences, Indianapo lis, IN), Medallion (Fludioxonil, Syngenta, Greensboro, NC), and Cleary 3336 and Chipco 26 GT (Iprodione, Bayer, Montvale, NJ) was maintained to adequately control disease symptoms in the nursery greenhouse. Pathogen Identification A dematiaceous fungu s was consistently isolated from naturally occurring lesions on tigergrass (Figure 3 2 ), and identified as Exserohilum rostratum based on conidial morphology (Figures 3 3 and 3 4) according to Sivanesans key (Sivanesan 1987).

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68 Inoculation of tigergrass wit h conidia of E. rostratum at different concentrations resulted in symptoms 1 3 days post inoculation (dpi), with symptoms appearing as early as 12 hours after inoculation when sprayed with 10 5 conidia/ml Increasing inoculum density corresponded with incre asing levels of disease severity (Figure 3 5) and decreasing incubation times. High levels of inoculum (10 5 conidia/ml) showed symptoms as early as 12 hours after inoculation, while at lower inoculation density levels symptoms appeared 2 5 days after inocu lation. E xserohilum rostratum was re isolated from the lesions resulting from the spray inoculation experiments. Fungal Characterization Exserohilum rostratum grew on all tested media (water, potato dextrose, V8 juice, and lactose caseine hydrolysate agars ), but sporulated most profusely and reliably on V8 juice agar, which was used for subsequent experiments. Sporulation typically only occurred after the mycelium had reached the edge of the petridish, 6 7 days after transfer to the medium. The mycelium was initially white in culture, turning dark brown as the culture aged. The conidiophores were brown and geniculate. Conidiogenesis was blastic and sympodial. The conidia were brown, straight to slightly curved, pseudoseptate, with the terminal septa dark and thick, with a protruding hilum, 11 18 m 56 128 m (Figure 3 3), most often germinating from both terminal cells of the conidium (Figure 3 4). The inoculum density of E. rostratum affected the final disease severity on tigergrass (Figure 3 5). Based on the results depicted in Figure 3 5, all subsequent experiments were performed with 5 10 3 conidia/ml, harvested from cultures 7 11 days old. The ITS1/4 sequences derived from several isolates were identical, and Blastn (Altschul et al. 1990) results indic ated 100% alignment with the E. rostratum sequence deposited in Genbank (gi:76555872). This confirmed the identity of the fungal plant pathogen as E. rostratum The

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69 Clustal W (Larkin et al. 2007 ) sequence alignment with the closest blast hit ( E. rostratum ) is displayed in Figure 3 6 One of the Blastn resulted with a very high similarity (99% over 92% of the sequence) with gi: 55586034 Alternaria sp.. This sequence is most likely mis identified by the depositors, since there were no other similar Alternaria Blast hits. In addition, the conidial morphology of E. rostratum was sufficiently distinct from those of Alternaria To visualize the conidia in association with lesions, leaf sections from leaves obtained from artificially inoculated plants with lesions were cleared with lactophenol blue. Figure 3 7 shows lesions on tigergrass associated with E. rostratum conidia. Exserhilum rostratum formed a very pronounced bulbous appressorium on one of the germ tubes. The appressoria (Figure 3 8) had two distinct cell walls and could clearly be seen to penetrate the tigergrass leaf surface. Effect of Soluble Silicon on Fungal Grow th I n V itro To assess the effect of soluble silicon on growth of E. rostratum plugs obtained with a # 1 hole punch (4 mm) from 3 day old E. r ostratum cultures were transferred to the center of a petri dish with V8 juice agar amended with different amounts of AgSil25, and to plates amended with different amounts of potassium hydroxide (KOH) to increase the pH. During initial experiments attempts were made to lower the pH of the medium. This failed as clumps formed immediately in the V 8 juice agar likely due to polymerization of silicon. Colony diameters were measured every 24 hours for each of three replicates per treatment. Results of the fir st experiment are summarized in Table 3 1, and graphically depicted in Figure 3 9. Both high pH and high silicon concentration suppressed the growth of E. rostratum on V8 juice agar, as indicated by final colony diameter and percent inhibition (Table 3 1). However, the inhibition observed on medium amended with silicon cannot be explained simply by increasing pH. KOH amended medium with pH level of 10.3 still supported fungal growth that was not significantly different from that of the control (4.6 % inhibit ion). However, a pH of 10.8 in plates

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70 with 4 ml AgSil25/100 ml resulted in 85.9 % inhibition. In addition, on KOH plates, a pH of 11.2 mycelial growth was only 55% inhibited, while on plates with 277 mM silicon with a pH of 11.3, growth was 100% inhibited. E. rostratum did not grow at all on medium with 277 mM silicon. An initial experiment also included 550 mM silicon, on which the fungus also did not grow. After 2 weeks, the non growing plugs were transferred to plain V8 juice agar to verify whether the ef fect of AgSil25 was fungistatic or fungitoxic. The plugs grew normally, and looked morphologically no different than control cultures after the transfer, indicating that the fungus had not died on the silicon amended agar. In a separate experiment, five re plicates of each treatment were used with the following treatments: control (no amendments of the medium), four levels of potassium silicate: 34, 68, 138, and 277 mM silicon (corresponding to 1, 2, 4, and 8 ml AgSil25/100 ml medium; Si 1, Si 2, Si 4, and S i 8), and four levels of potassium hydroxide (KOH 1, KOH 2, KOH 3, and KOH4) with pH adjusted to appro ximately the same level as the four potassium silicate treatments. The results are summarized in Table 3 2. As in the first experiment, high pH negatively affected colony growth at the highest level only (by 42.5 %, KOH 4), while a pH of 10.3 resulted in a 5.3% inhibition of growth, which was not statistically significant compared to the control In contrast, soluble silicon at a level of 139 mM silicon (pH 10.4) resulted in a 71.3% inhibition of growth. The 277 mM silicon treatment (pH 10.6) resulted in complete (100%) inhibition of growth of E. rostratum while KOH 4 (pH 10.7) resulted in 42.5% inhibition of growth. In a third repeat of the experiment, si x replicates were used per treatment, and the same treatments were used (KOH 1 through 4, Si 1, 2, 4, and 8), with the KOH treatments adjusted to approximately the same pH as the four silicon treatments. The results are summarized in Table 3

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71 3. As in the f irst and second experiment, E. rostratum did not grow at all on the highest level of silicon (277 mM silicon, pH 10.9), while there was growth on KOH 4 (pH 11.1), albeit 33.2 % inhibited. On medium with 139 mM silicon, E. rostratum only started growing on the 4 t h day after transfer, growth was inhibited 90.5% after 5 days (Figure 3 12). To test whether E. rotratum took up silicon from the amended medium, the mycelium was carefully scraped off the plates, and allowed to dry for silicon analysis. Since each p late yielded very small amount of dry fungal tissue, the mycelium from all samples per treatment was pooled for analysis. No autoclave induced digestion of the fungal tissue was necessary. The results are in Table 3 4. Exserohilum rostratum grown on plates amended with AgSil25 does not appear to accumulate silicon Effect of Silicon on Resistance of Tigergrass to Exserohilum rostratum Tigergrass plugs were grown in 100 mm pots for 4 weeks using 5 treatments: no amendment control, and AgSil25, Excellerator, and Wollastonite at a rate equivalent to 1.4 0 kg elemental s i licon / m 3 as described in the materials and methods section, and three replicates per treatment were inoculated with 5 10 3 conidia/ml. Inoculated plants were placed in the high humidity chamber (87 100%, Figures 3 1) immediately after inoculation for 24 hours. The front plastic sheet was removed, and plants were monitored for disease development over 14 days. Disease symptoms were scored using the Horsfall Barratt scale (Horsfall and Barratt 194 5). At the time of inoculation, one plant from each treatment was harvested to determine silicon concentration in the leaves (Table 3 5). At the end of the experiment (day 14), tigergrass plants were harvested for the determination of the silicon leaf conc entration. The silicon concentration of the leaf tissue differed depending on the treatment. Control plants had low levels of silicon (0.23%), Excellerator and Wollastonite treated plants had high levels of silicon (1.08 and 0.96, respectively), and AgSil2 5 treated plants had an intermediate

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72 level of silicon. Disease symptoms appeared on the 5 t h day after inoculation, except for the plants in pots amended with AgSil25, on which symptoms appeared a day later. The disease progress curve, (Figure 3 13), final disease severity (Figure 3 15 ), and final Area Under Disease Pr ogress Curve (AUDPC, Figure 3 14 ), showed that pots treated with AgSil25 had the lowest AUDPC 14 days after inoculation. Although plants amended with Excellerator and Wollastonite had lower mea ns of final disease severity and AUDPC than the control, this difference was not significant. In a second experiment, plants were inoculated at 6 weeks after planting and monitored for 19 days. On the day of inoculation one plant of each treatment was har vested for silicon analysis, and all plants were harvest ed at the end of the experiment to determine silicon concentration of the leaves. The results of the tigergrass silicon analyses for the second experiment are listed in Table 3 6. Silicon amended plan ts had significantly more silicon than control plants, both at the time of inoculation and at the time of harvest, 19 days later. As in the first experiment, a lthough no statistical analysis was done on the plants harvested on day 0, because only one plant was harvested per treatment, the data does suggest that the silicon amended pants continue d to accumulate silicon during the 19 days after inoculation. Symptoms were visible on the 6 t h day after inoculation for control and Wollastonite amended plants. On Excellerator amended plants the first symptoms appeared on the 7 t h day, and on AgSil25 amended plants on the 8 t h day after inoculation. The disease progress curves are shown in Figure 3 16. The disease severity on plants amended with AgSil25 remained gener ally below that of other treatments until the 18 t h day after inoculation, while disease severity on control was highest throughout the experiment. Leaf spot severity on Excellerator and Wollastonite amended plants was intermediate between that of the contr ol and AgSil25 amended plants. From the 9 t h to the 15 t h day, control plants had a significant ly higher disease severity than

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73 on silicon amended plants. Control, AgSil25, Excellerator, and Wollastonite amended plants had final disease severities of 16.1, 14 .8, 14.2, and 14.1%, respectively, which were not significantly different between an y of the treatments (Figure 3 18 ). The final AUDPC was significantly decreased by 46% in AgSil25 amended plants, by 34% in Excellerator amended plants, and 32% in Wollaston ite amended plants in comparison to the controls (Figure 3 17 ). The final AUDPCs of the silicon amended plants did not differ statistically from each other, and AgSil25 amended plants, as in the first experiment, had numerically the lowest final AUDPC. D iscussion and Conclusions Exserohilum rostratum (Drechsler) Leonard & Suggs was positively identified as the causal agent of tigergrass leaf spot disease using morphological and molecular characteristics, and performing Kochs postulates. This fungal patho gen has not previously been reported on tigergrass before, although it is known to be common on grasses, other plants and substrates, and in soil (Sivanesan 1987). Even relatively low levels of inoculum (10 3 conidia/ml) result ed in substantial disease seve rity in artificial inoculation experiments. Inoculation of tigergrass at high inoculum densities (10 5 conidia/ml) caused such severe leaf spot symptoms that the coalescing lesions resulted in widespread necrosis and death of the leaf. This implied that the disease has the potential to be severe under natural conditions. Indeed, tigergrass supplied by the grower were often heavily infected. Exserohilum rostratum is the anamorph of Setosphaeria rostrata Leonard. The species is heterothallic, producing a teleo morph in vitro after culturing different mating types at low temperature for 1 3 months (Sivanesan 1987). From a commercial marketing point of view any disease symptoms on the plants at the time of sale would be completely unacceptable.

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74 Most conidia of E. rostratum germinated bipolarly. The fungus produced prominent appressoria that were ass ociated with tigergrass lesions Individual lesions expanded longitudinally, and were for the most part restricted to between the leaf veins. However, multiple lesions could coalesce into larger diseased areas that mig ht span the veins. Symptoms appear ed at times very rapidly, implying that fungal toxins may be involved in the infection process. Indeed, the genus Exserohilum belongs to what was formerly called the genus Helminthosporium to which a number of species belong that produce host specific toxins (Sivanesan 1987). Inhibition of mycelial growth on medium amended with soluble silicon was reported by Kaiser et al. (2005) for several fungi, including Drechslera spp. that are closely related to Exserohilum spp. (Sivanesan 1987). In that study however, the plugs that failed to grow on silicon amended medium were not transferred to media without silicon to test whether the effect was fungistatic or fungicidal. Bi et al (2006) did a similar experiment, but used sodium silicate to amend the medium and found that mycelial growth of Alternaria alternata Fusarium semitectum and Trichothecium roseum were diminished. The authors did transfer the plugs to non amended medium after the experiment, found that they grew normally, and concluded the effect was fungistatic. Several factors make it hard to draw definitive conclusions fr om that experiment. First the source of silicon was added to the medium before autoclaving, which would have caused polymerization of the silicate into insoluble silica gel, thereby changing the amounts of soluble silicon. Second, sodium silicate would have caused an increase in medium pH, and the effect of pH was not tested. Finally, no control was ad ded to investigate whether the effect could have been due to the increased concentration of sodium.

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75 In contrast, in this study, filter sterilized potassium silicate solution was added to V 8 ju ice agar once it had cooled to 55 C which prevented polymeriz ation. Soluble silicon in the growing medium inhibited mycelium growth of E. rostratum significantly, and the results were consistent in three separate experiments. The effect was determined to be fungistatic, since the plugs grew normally when they were t ransferred to regular V 8 juice agar at the end of the experiment, and could not be explained exclusively by the increased pH of the soluble silicon amended medium, or the increased concentration of potassium in the medium. There is some evidence that spr aying potassium silicate decreases fungal infection. On grape leaves, soluble silicon sprays inhibited powdery mildew ( Uncinula necator ) development (Bowen et al. 1992), while on cucumber foliar applications of silicon, suppressed powdery mildew ( Podosphae ra xanthii ; Liang et al. 2005). Bi et al. (2006) dipped Hami melons in a sodium silicate solution and found that this inhibited mycelial growth of A alternata Howev er, it is unclear whether this wa s due to silicate or sodium, since the control treatment consisted of dipping in water. This is particularly important because Aharoni et al. (1997), in a similar experiment, found that melons dipped in sodium bicarbonate showed reduced decay caused by A. alternata Fusarium spp., and Rhizopus stolonifer without testing whether this was due to sodium or bicarbonate. In addition, Bi et al (2006) did not measure the silicon concentration of the melon rind to determine whether silicon was p resent It is possible that in the E. rostratum tigergrass system soluble si licon plays a role in the in planta infection process, when the penetration peg penetrates the epidermal wall and goes through the relatively high silicon concentration silica depositions. An inhibition of penetration peg growth might result in the plant h aving more time to rally defense mechanisms against the fungal attack, or the defense mechanisms may be more effective on an impeded penetration peg.

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76 An alternative interpretation could be that the fungus penetrates the silica layer underneath or above the cuticle, thereby releasing silicate monomers in locally high concentration, and that this decreases the rate of penetration peg advancement In contrast, Kema et al. (1996) concluded that polymerized silicon did not prevent penetration of Mycosphaerella g raminicola in wheat, but that does not exclude the possibility that penetration peg development is slowed or weakened. In these experiments, E. rostratum did not acc umulate silicon itself, but the measurements may not be accurate. If silicon is present at low concentrations in the medium, it may not be possible with the techniques used in this study to measure the difference in silicon concentration of fungal mycelium grown on plates with and without silicon. With higher silicon concentrations t here was no fungal growth so silicon concentration could not be determined. In the first of two experiments, only AgSil25 amendment applied at 1.4 0 kg elemental silicon/ m 3 was associated with a statistically significant decreased disease severity and AUDPC of tigergr ass to E. rostratum infection H owever, the final disease severity and AUDPC was not significantly different with AgSil25 amendment from that of the other silic on amendment s. Plants amended with AgSil2 accumulated 56% less silicon than plants amended with Excellerator and 50% less than plants amended with Wollastonite in this experiment. In the second experime nt, the final disease severity wa s not significantly different between any of the silicon treatments. The fact that the A UDPC of AgSil25 amended plant s wa s 86% less than the control in the first experiment, but only 46% less in the second experiment wa s likely due to the disease severity on AgSil25 amended plants ending up with the same final disease severity as control plants towards the end of the exp eriment. The difference in final AUDPC in the first experiment is likely due to the delayed appearance of the symptoms on AgSil25 amended plants (2 days later), even though the final

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77 disease severity was not different. Similarly, in the second experiment t he final AUDPC was significantly different between the control and all silicon amended plants (Figure 3 18). At different points of time during the experiment, the silicon amended treatments did have a significantly lower disease severity than control plan ts, particularly during the second experiment. From day 9 through 15 after inoculation, the disease severity on control plants was significantly higher than all silicon amended plants. This no longer held true for Wollastonite amended plants on day 16, whi le Excellerator amended plants and AgSil25 amended plants caught up on day 17 and 18 respectively. This difference in disease severity between control and silicon amended plants throughout the observation period explains the difference in AUDPC between con trol plants and silicon amended plants. Brecht et al. (2004) noted a similarly decreased final AUDPC in the gray leaf spot St. Augustinegrass system, even when the final disease severity was not different from non amended plants, due to differences in d isease severity at different points of time during the experiment. An increased incubation period was correlated with increasing rates of silicon application in the rice rice blast system (Seebold et al. 2001), but not clearly affected by silicon amendment in the rice sheath blight ( Rhizoctonia solani ) system (Rodrigues et al. 2003b). In light of results reported herein, there is ample opportunity to continue research in the tigergrass Exserohilum system. It may be useful to investigate different rates of s ilicon in addition to the use of different silicon sources to provide more detail as to the ir relationship between silicon concentration and disease severity and AUDPC. Other components of tigergrass resistance might be affected, but which were not assesse d in this study are lesion size and the rate of lesion expansion. Further research in this system might yield more generalized principles of the basis of silicon correlated disease resistance.

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78 In conclusion, E. rostratum was confirmed to be the causal agen t of tigergrass leaf spot. Silicon amendment increased the resistance of tigergrass to E. rostratum as determined by the lower AUDPC for silicon amended plants compared to that of the control plants.

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79 Table 3 1 E ffect of potassium hydroxide and potassium silicate on colony diameter and percent inhibition of growth of Exserohilum rostratum after 5 days, first experiment M e d i u m a m e n d m e n t p H D i a m e t e r ( c m ) x I n h i b i t i o n ( % ) y C o n t r o l ( n o a m e n d m e n t ) 6 1 8 0 c z 0 c K O H 1 w 7 0 7 7 c 4 6 c K O H 2 9 0 7 6 c 5 8 c K O H 3 1 0 3 7 7 c 4 6 c K O H 4 1 1 2 3 6 b 5 5 2 b S i 1 ( 3 4 m M S i ) 9 3 7 9 c 1 2 c S i 2 ( 6 8 m M S i ) 1 0 1 6 9 c 1 3 7 c S i 4 ( 1 3 9 m M S i ) 1 0 8 1 1 a 8 5 9 a S i 8 ( 2 7 7 m M S i ) 1 1 3 0 a 1 0 0 a w K O H 1 t h r o u g h 4 m e d i a w e r e p H a d j u s t e d w i t h p o t a s s i u m h y d r o x i d e t h e s a m e p H a s t h e S i 1 t h r o u g h 8 m e d i a x A v e r a g e d i a m e t e r o f c o l o n i e s o n V 8 j u i c e a g a r a m e n d e d w i t h p o t a s s i u m h y d r o x i d e o r p o t a s s i u m s i l i c a t e 5 d a y s a f t e r t r a n s f e r y P e r c e n t i n h i b i t i o n w a s c a l c u l a t e d b y e x p r e s s i o n t h e d i f f e r e n c e i n c o l o n y d i a m e t e r o f c o n t r o l a n d t r e a t m e n t p l a t e s a s a p e r c e n t a g e o f t h e a v e r a g e d i a m e t e r o n t h e c o n t r o l p l a t e z M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 ) Table 3 2 Effect of potassium hydroxi de on colony diameter and percent inhibition of growth of Exserohilum rostratum after 5 days second experiment T r e a t m e n t p H D i a m e t e r ( c m ) x I n h i b i t i o n ( % ) y C o n t r o l ( n o a m e n d m e n t ) 6 4 8 0 a z 0 a K O H 1 w 8 5 7 5 a 5 5 e K O H 2 9 1 7 6 a 5 e K O H 3 1 0 3 7 6 a 5 3 e K O H 4 1 0 7 4 6 c 4 2 5 c S i 1 8 7 7 7 a 3 5 e S i 2 9 3 6 3 b 2 0 6 d S i 4 1 0 4 2 3 d 7 1 3 b S i 8 1 0 6 0 e 1 0 0 a w K O H 1 t h r o u g h 4 m e d i a w e r e p H a d j u s t e d w i t h p o t a s s i u m h y d r o x i d e t h e s a m e p H a s t h e S i 1 t h r o u g h 8 m e d i a x A v e r a g e d i a m e t e r o f c o l o n i e s o n V 8 j u i c e a g a r a m e n d e d w i t h p o t a s s i u m h y d r o x i d e o r p o t a s s i u m s i l i c a t e 5 d a y s a f t e r t r a n s f e r y P e r c e n t i n h i b i t i o n w a s c a l c u l a t e d b y e x p r e s s i o n t h e d i f f e r e n c e i n c o l o n y d i a m e t e r o f c o n t r o l a n d t r e a t m e n t p l a t e s a s a p e r c e n t a g e o f t h e a v e r a g e d i a m e t e r o n t h e c o n t r o l p l a t e z M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 )

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80 Table 3 3 Effect of potassium hydroxide on colony diameter of Exserohilum rostratum after 5 da ys third experiment T r e a t m e n t p H D i a m e t e r ( c m ) x I n h i b i t i o n ( % ) y C o n t r o l ( n o a m e n d m e n t ) 6 2 8 2 a z 0 f K O H 1 w 9 2 8 1 a 1 4 f K O H 2 9 8 7 4 b 1 0 3 e K O H 3 1 0 7 6 5 c 2 0 9 d K O H 4 1 1 1 5 5 d 3 3 2 c S i 1 ( 3 4 m M S i ) 9 1 7 9 a 4 5 f S i 2 ( 6 8 m M S i ) 9 9 6 3 c 2 3 2 d S i 4 ( 1 3 9 m M S i ) 1 0 5 0 8 e 9 0 5 b S i 8 ( 2 7 7 m M S i ) 1 0 9 0 f 1 0 0 a w K O H 1 t h r o u g h 4 m e d i a w e r e p H a d j u s t e d w i t h p o t a s s i u m h y d r o x i d e t h e s a m e p H a s t h e S i 1 t h r o u g h 8 m e d i a x A v e r a g e d i a m e t e r o f c o l o n i e s o n V 8 j u i c e a g a r a m e n d e d w i t h p o t a s s i u m h y d r o x i d e o r p o t a s s i u m s i l i c a t e 5 d a y s a f t e r t r a n s f e r y P e r c e n t i n h i b i t i o n w a s c a l c u l a t e d b y e x p r e s s i o n t h e d i f f e r e n c e i n c o l o n y d i a m e t e r o f c o n t r o l a n d t r e a t m e n t p l a t e s a s a p e r c e n t a g e o f t h e a v e r a g e d i a m e t e r o n t h e c o n t r o l p l a t e z M e a n s i n e a c h c o l u m n f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 ) Table 3 4 Silico n concentration ( cg/gm ) of Exserohilum rostratum grown on V 8 juice agar with soluble silicon amendment T r e a t m e n t E x p e r i m e n t 1 y E x p e r i m e n t 2 E x p e r i m e n t 3 C o n t r o l ( n o a m e n d m e n t ) 0 0 0 6 0 0 0 0 2 K O H 1 0 0 0 7 0 0 0 9 0 K O H 2 0 0 0 5 0 0 1 1 0 0 0 5 K O H 3 0 0 0 5 0 0 0 6 0 0 0 2 K O H 4 0 0 0 2 0 0 0 2 0 S i 1 ( 3 4 m M S i ) 0 0 0 5 0 0 0 2 0 0 0 5 S i 2 ( 6 8 m M S i ) 0 0 0 2 0 0 0 4 0 0 0 2 S i 4 ( 1 3 9 m M S i ) N o t d o n e z 0 0 0 2 N o t d o n e S i 8 ( 2 7 7 m M S i ) N o t d o n e N o t d o n e N o t d o n e y N o s t a t i s t i c a l a n a l y s i s w a s d o n e s i n c e t h e r e w e r e n o r e p l i c a t e s z N o g r o w t h Table 3 5 Silicon concentration of tigergrass leaves at the time of inoculation (day 0) and the time of harvest (day 14), first e xperiment T r e a t m e n t S i ( c g / g m ) o n d a y 0 S i ( c g / g m ) o n d a y 1 4 B l a n k c o n t r o l 0 2 1 0 2 3 a x A g S i l 2 5 0 3 6 0 4 8 b E x c e l l e r a t o r 0 5 0 1 0 8 c W o l l a s t o n i t e 0 4 9 0 9 6 c x M e a n s f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 )

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81 Table 3 6 Silicon concentration of tigergrass leaves at the time of inoculation (day 0) and the time of harvest (day 19), second experiment T r e a t m e n t S i ( c g / g m ) o n d a y 0 S i ( c g / g m ) o n d a y 1 9 B l a n k c o n t r o l 0 2 6 0 3 0 b x A g S i l 2 5 0 9 7 1 0 8 a E x c e l l e r a t o r 1 0 0 1 1 7 a W o l l a s t o n i t e 0 8 9 1 1 6 a x M e a n s f o l l o w e d b y d i f f e r e n t l e t t e r s a r e s i g n i f i c a n t l y d i f f e r e n t b a s e d o n F i s h e r s p r o t e c t e d L S D ( # = 0 0 5 )

PAGE 82

82 Figure 3 1 Shelf enclosed in plastic used for keeping plants at high humidity for the firs t 24 hours after inoculation.

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83 Figure 3 2 Tigergrass showing leaf spot symptoms on day of receipt from the supplier. Note the tan colored lesions that are typical for the disease.

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84 Figure 3 3 Conidia of Exserohilum rostratum Note the protruding hi lum (arrow) which distinguishes the genus Exserohilum from the genus Bipolaris

PAGE 85

85 Figure 3 4 Bipolar conidial germination of Exserohilum rostratum

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86 Figure 3 5 The effect of inoculum density on Exserohilum rostratum leaf spot development on tigergrass Numbers on the right indicate the number of conidia/ml. Increasing concentration results in higher disease severity.

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87 Figure 3 6 ITS sequence alignment. ITS1/4 sequences derived from Exserohilum rostratum isolate 0706019 compared with the ITS sequence from GenBank gi:76555872 Exserohilum rostratum

PAGE 88

88 Figure 3 7 Association of conidia of Exserohilum rostratum with lesions on tigergrass. The light colored areas of the leaves are the lesions. Exserohilum rostratum conidia in this picture have formed a n appressorium in the infection process

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89 Figure 3 8 Exserohilum rostratum forms distinct appressoria (arrows) in the process of infecting tigergrass. The leaves were cleared and stained with lactophenol blue..

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90 Figure 3 9 Growth of Exserohilum rostr atum on V8 juice agar amended with soluble silicon (AgSil) or potassium hydroxide (KOH) first experiment. Silicon concentrations Si 1: 34 mM, Si 2: 69 mM, Si 4: 139 mM, Si 8: 277mM. Media KOH 1 KOH4 were adjusted to the same pH as the four silicon amend ed media at the start of the experiment.

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91 Figure 3 10 Growth of Exserohilum rostratum on V8 juice agar amended with soluble silicon (AgSil) or potassium hydroxide (KOH), second experiment. Silicon concentrations Si 1: 34 mM, Si 2: 69 mM, Si 4: 139 mM, Si 8: 277mM. Media KOH 1 KOH4 were adjusted to the same pH as the four silicon amended media at the start of the experiment.

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92 Figure 3 11 Growth of Exserohilum rostratum on V8 juice agar amended with soluble silicon (AgSil) or potassium hydroxide (KO H), third experiment. Silicon concentrations Si 1: 34 mM, Si 2: 69 mM, Si 4: 139 mM, Si 8: 277mM. Media KOH 1 KOH4 were adjusted to the same pH as the four silicon amended media at the start of the experiment.

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9 3 Figure 3 12 Growth inhibition of Exserohil um rostratum in vitro on medium containing soluble silicon. Silicon concentration s Si 1: 34 mM, Si 2: 69 mM, Si 4: 139 mM, Si 8 : 277mM. Media KOH 1 KOH4 were adjusted to the same pH as the four silicon amended media at the start of the experiment. Note tha t the fungus did not grow on media with higher silicon concentrations, while there was still growth on KOH media adjusted to the same pH.

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94 Figure 3 13 Development of tigergrass leaf spot severity caused by Exserohilum rostratum (5 10 3 ) over a 14 day period. Data were arcsine transformed before anova was performed, first experiment.

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95 Figure 3 14 Final Area Under Disease Progress Curve (AUDPC) for tigergrass leaf spot caused by Exserohilum rostratum first experiment.

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96 Figure 3 15 Final tigergras s leaf spot severity caused by Exserohilum rostratum first experiment.

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97 Figure 3 16 Development of tigergrass leaf spot severity caused by Exserohilum rostratum (5 10 3 ) over a 19 day period. Data were arcsine transformed before anova was performed, s econd experiment.

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98 Figure 3 17 Final Area Under Disease Progress Curve (AUDPC) for tigergrass leaf spot, 19 days after inoculation, second experiment.

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99 Figure 3 18 Final disease severity of tigergrass at 19 days after inoculation with Exserohilum rost ratum second experiment.

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100 CHAPTER 4 EFFECT OF SILICON AM ENDMENT ON GENE EXPRESSION PATTERNS IN RICE Introduction R ice cultivars lacking major resistance genes are nevertheless highly resistant to the rice blast pathogen M agnaporthe grisea (T.T. Hebert) M. E. Barr when supplemented with silicon comparable to the level obtained by application of a fungicide (Datnoff and Rodrigues 2005 ). Seebold et al. (2004) showed that in upland rice, leaf and neck blast could be controlled with silicon at least as effectiv ely as with fungicide application if disease severity was low. At high disease severity, fungicide applied at 10% the normal rate in addition to silicon amendment was sufficient to control the disease Sheath blight of rice caused by Rhizoctonia solani J. G. Kuhn was reduced between 17% and 82% by silicon application equivalent to 10 t /ha, depending on the inherent resistant of the rice cultivar (Rodrigues et al. 2001). Two main hypotheses have been proposed to explain the resistance of silicon amended plan ts to infection by fungal pathogens. One hypothesis proposes that the insoluble silicon layer deposited on the epidermal cells prevent s fungal penetration (Volk et al. 1958), and is referred to as the mechanical barrier hypothesis. An alternative hypothe sis proposes that silicon affects the response of the rice plant at a biochemical level. F or example in cucumber, Chrif et al. (1992) found that resistance against Pythium ultimum was enhanced even though silicon did not accumulate at penetration points u nder saturated humidity. Evidence for both hypotheses has been reported. In support of the physical barrier hypothesis, X ray analysis (Kim et al. 2002) and NMR spectroscopy (Park et al. 2006) showed the presence of a layer of silicon in the epidermal cell wall of rice leaves, with a gradient of increasing amounts of silicon towards the outside of the cell (Kim et al. 2002). Kim et al. (2002) did not detect any silicon in the epidermal cytoplasm,

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101 but Neumann and De Figueiredo (2002) reported on the presence of silicon in the cytoplasm of several heavy metal tolerant plants and Arabidopsis thaliana Carver et al. (1987) found that higher silicon levels correlated with an increase in failed fungal penetrations. Several lines of evidenc e support the role of sil icon as a molecular signal 1) The activation of the terpenoid pathway was indicated by the accumulation of diterpenoid isoprenoid phytoalexins in rice leaves of plants amended with silicon and inoculated with M. grisea (Rodrigues et al. 2004). 2) The surr ounding of fungal hyphae in planta by an amorphous phenolic like compound was associated with, and served as another indicator of events that played a role at a molecular level in the silicon mediated blast resistance of rice (Rodrigues et al. 2003 a ). 3) The inoculation of silicon amended rice plants with M. grisea resulted in the differential expression of a number of known plant defense genes (Rodrigues et al. 2005). Fauteux et al. (2006) were the first to study the interaction at a genome wide level bet ween silicon amendm ent and a fungal plant pathogen In a microarray study that involved the entire A. thaliana genome, they found a limited number of differentially expressed genes in silicon amended plants compared to control plants, while powdery mildew ( Erysiphe cichoracearum DC) inoculated plants compared to control plants had almost 4000 differentially expressed genes. They concluded that silicon had no direct effect on A. thaliana metabolism, and that the effect of silicon was limited to attenuating t he reaction of the host to pathogen infection by decreasing the number of differentially expressed genes in response to pathogen infection in silicon amended plants The objective of the study reported in this chapter was to describe the effect of silico n on the molecular response of rice to pathogen infection on a genome wide scale To this end, microarrays containing ~44,000 probes representing 41,863 transcripts were used in a loop

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102 design to identify genes differentially expressed in the rice cultivar Monko to with and withouth silicon amendment in response to inoculation with M. grisea 86 137 Differentially expressed genes were identified in silicon amended plants and pathogen inoculated plants versus control plants, and in the interaction between sil icon amendment and pathogen inoculation. Materials and Methods The technical part of this experiment was performed in Japan, in the laboratory of Dr. Jian Feng Ma. This chapter focuses on the analysis of the data performed at the University of Florida Ric e (japonica cultivar Monko to) was grown hydroponically in half strength Kimura B solut ion with (2 mM) or without silicon [ treatments Si and C (control), respectively] At the four five leaf stage, half of both the control and silicon amended plants were i noculated with the rice blast pathogen, M. grisea 86 137. This resulted in four treatments (Table 4 1). Monko to contains no known major resistance genes against M. grisea and is highly susceptible without silicon amendment. Whole plants of each trea tment were harvested 24 hours after inoculation, and immediately frozen in liquid nitrogen for mRNA extraction. cDNA was prepared from all the mRNA populations by reverse transcription divided into two groups each, one of which was labeled with Cy 3 (labe led blue in Figure 4 1 ), the other with Cy 5 (labeled red). The experiment was set up in a loop design that hybridized two cDNA population samples labeled with different colors to the same slide (with a duplicate slide containing the reverse color labels). This resulted in 8 slides as indicated in Figure 4 1. The cDNA from control plants was thus hybridized to the same slide as silicon amended plants (C vs Si), and to the same slide as pathogen inoculated plants (C vs P). Silicon amended and pathogen inocul ated plants were also hybridized to the same slide as silicon amended and pathogen inoculated plants (Si vs SiP and P vs SiP, respectively).

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103 Spot intensity data was normalized using quantile normalization (Bolstad et al. 2003 ), followed by mixed model analysis of v ariance (Littell et al. 1996 ) with treatment as a fixed effect. Significant differentially expressed genes were identified using a t test (Jin et al. 2001) and corrected for multiple tests using a modified false discovery rate using the Bioco nductor QVALUE software packages (Storey 2002; Storey and Tibshirani 2003; Storey et al. 2004 ) running under the R 2.7.2 environment for statistical computing and graphics (Ihaka and Gentleman 1996; http://www.r proje ct.org/ ). Differentially expressed genes for each treatment comparison was based on both the significance to the q value calculated by QVALUE, and the foldchange in expression. Genes with a q value<0.001 were selected, and further narrowed down by taking only into account genes with greater than 3 fold up or down regulation. Data were plotted using R. (Ihaka and Gentleman 1996; http://www.r project.org/ ). Results The Volcano plot s in Figures 4 2 through 4 5 illustra te the distribution of data points, the significance of the measured differences in expression levels, and the selection of differentially expressed genes for each of the four comparisons. Each dot represents one of 41863 spots on the microarray. The black dots represent genes with a low significance (q & 0.001 ), the dotted horizontal line is q=0.001. The blue dots represent spots that have q<0.001, but a foldchange< 3 The red dots are the genes selected as differentially regulated (q<0.001, foldchange>3). Th e number of differentially expressed genes for each of the arrays is indicated in Figure 4 1 as the number of up and down regulated genes for ea ch pair of treatments compared. Differentially expressed genes were divided into categories based on known or s uspected function or activity. The distribution of differentially expressed genes for each comparison of treatments into defense genes, unknown genes, and other genes, is in Table 4 3 and Figure 4 6. The category of other

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104 genes is further divided and dif ferentially expressed genes in each of the categories are listed in appendices A through J with their expression profiles (whether the genes up and/or downregulated for each of the treatment comparisons). Silicon amendment In plants that were gro wn in the presence of silicon, 2 21 genes were differentially expressed compared to control plants. Of these, 105 genes were upregulated, and 116 genes were downregulated (Figures 4 1 and 4 2). Nine of the upregulated and 19 of the downregulated genes are known or im plicated to be involved in defense and stress pathways Among the genes that are differentially regulated in silicon amended plants compared to control plants are a metal transporter encoding gene (Os07g0258400), peroxidase precursor encoding genes (Os01g0 378100, Os01g0963200, Os03g0235000), 11 putative plant resistance proteins, and a Type 1 pathogenesis related protein encoding gene (Os10g0191300). Among the transcription factor encoding genes that are differentially regulated in the silicon amended plant s, six genes are unique, and three are WRKY transcription factor encoding genes. There are many genes differentially regulated that are involved in cellular housekeeping processes, their expression profiles are listed in appendix E. Forty three percent of all differentially expressed genes are of unknown function. Pathogen inoculation Not surprisingly, a large number of differentially expressed genes in this study were in the comparison of control plants and pathogen inoculated plants (738), most were upreg ulated (618). Among the differentially expressed gene in respons e to pathogen inoculation, 59 were upregulated and 13 were downregulated defense or stress related genes (Table 4 3, Figure 4 6, appendix A), 65 were upregulated transcription factor encoding genes, and 13 were downregulated transcription factor encoding genes (appendix B), and 20 genes involved in

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105 hormone signaling pathways (appendix D). Interestingly, all genes that were categorized as calcium signaling related, were upregulated in the pathog en inoculated plants compared to the control plants (appendix H). Also 65 genes were identified as kinase/phosphatase encoding genes (59 upregulated, 6 downregulated). Thirty seven percent of differentially regulated genes in response to the pathogen were unknown. Silicon pathogen interaction The main purpose of this study was to investigate the interaction between silicon amendment and pathogen inoculation on the transcriptional profile of rice. The comparisons Si vs SiP, and P vs SiP illustrate this inter action (Figures 4 1, compare Figure 4 4 with Figure 4 5, Figure 4 6). When the response of the plant to pathogen infection was compared between control (C vs P) and silicon amended plants (Si vs SiP), the silicon amended plants responded with 298 different ially expressed genes, while the control plant responded with more than 738. P vs SiP compared two groups of pathogen inoculated plants, and showed that there wa s a difference between silicon amended plants and non amended plants. In s i licon amended rice, 63 gen es we re upregulated in response to infection bv M. grisea while 123 genes we re downregulated compared to non amended rice of which 54 genes we re unique Compared to 59 upregulated pathogenicity/stress and 13 downregulated related genes in response to pathogen inoculation of control plants, only 30 were upregulated in response to pathogen inoculation of silicon amended plants, and two were downregulated. Similarly, the number of transcription factor encoding genes in response to pathogen inoculation of silicon amen ded plants (32 upregulated and two downregulated genes) wa s lower than the 65 upregulated and 13 downregulated once in response to inoculation of non amended ones. Two genes putatively involved in the auxin signaling pathway (auxin conjugate hydrolase encoding Os01g0706900 and auxin responsive SAUR family protein encoding Os08g0452500)

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106 we re upregulated in response to pathogen inoculation non amended plants, but not in response to pathogen inoculation of silicon amended plants. Of the 18 genes encoding putative calcium signaling pathways that were upregulated in response to pathogen i noculation of control plants, ten were upregulated upon inoculation of silicon amended plants. Discussion and Conclusions From the volcanoplots derived from the d ata collected in this study, it is clear that a large number of genes were significantly differentially expressed. There were also genes that had a large but not significant foldchange. It was therefore crucial to base initially the cutoffs on significance values, and narrow down the pool of differentially expressed genes by thresholding the foldchange cutoff. Dividing the treatment plants at least in groups of two before isolating mRNA, instead of isolating mRNA from the pooled plants, would have resulted in two biological replicates of each sample. Evidence for a role of silicon as molecular signal was apparent from the differential expression of 221 genes in the control versus silicon amended (C vs Si) comparison, and the fact that 28 of those genes are k nown or suspected to be involved in defense or stress response by the plant. The differential expression of a metal transporter gene (Os07g0258400) is of interest because silicon is reported to alleviate heavy metal stress (Ma et al 2001 b ; Williams and Vl amis 1957). Heavy metal transport/detoxification protein encoding gene s were differentially regulated; however, one was unique to the Si SiP comparison (expressed in response to pathogen infec tion of silicon amended plants) and three in response to pathoge n infection of non amended plants. Gene expression in silicon amended rice was markedly different from expression in non amended plants, which indicates that silicon amendment had a n effect on metabolic activity in

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107 rice. This is in contrast to the results obtained in a similar study done with the Arabidposis thaliana powdery mildew interaction (Fauteux et al. 2006), which found only two genes differentially expressed in silicon amended plants compared to control plants. One of these encoded an esterase lipa se thioesterase family protein the other a multicopper oxidase t ype I family protein (At1g21860); a weak homolog (25% identical, 44% similar) of the latter was also downregulated (Os11g06415) in silicon amended rice. Fauteux et al. (2006) concluded that Si alone has apparently no effect on the metabolism of plants growing in a controlled envi ronment (e.g., unstressed), thus confirming its nonessentiality in plant growth; supplying silicon alleviates the stress such as one imposed by a pathogen. From the results of the experiment described in this chapter, it appears that silicon differs from A. thaliana in this respect and does affect rice metabolism. This may be a difference in the role of silicon between Arabidopsis and rice, and/or a difference in rela tionship between the host plants and their respective pathogens in the systems studied. Powdery mildew of Arabidopsis is caused by Erysiphe cichoracearum an obligate parasite, while M. grisea is a hemi biotroph initially acting as a biotroph, and switchin g to a necrotrophic mode of pathogenicity A biotroph requires the host cells to be alive, whereas a necrotroph seeks to kill the host and live off the dead material. The differences found between the transcriptional response of the rice rice blast and the Arabidopsis powdery mildew systems could also be a reflection of the fact that silicon appears to have many benefits to rice, including resistance against lodging, higher yields, greater requirement for silicon during flowering and seed set (Datnoff et al 2001, Epstein 1991, Ma et al. 1989, Savant et al. 1997) while increased resistance of A. thaliana to powdery mildew is the only reported benefit of silicon in A. thaliana (Ghanmi et al. 2004).

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108 The results described herein are harder to reconcile with the report by Watanabe et al. (2004) who did an experiment using ~9000 rice genes. They found 20 candidate transcripts differentially regulated, and confirmed five by reverse transcription polymerase chain reaction. They included transcripts for a zinc finger protein, a metallthionein like protein, chlorophyll a/b binding protein, XA21 family member, and a carbonic anhydrase. The methodology used in Watanabes study was very different than the one used in this study, and therefore it is hard to draw parallels or far reaching conclusions on comparing the two studies. The arrays Watanabe et al. (2004 ) used contained less than 9000 transcripts, each sample was hybridized to one sample, and transcriptional levels were determined by comparison with tubulin and actin expression levels, and conclusions were drawn based on foldchange only. All the genes that were upregulated in th e study by Watanabe et al. (2004 ) were represented on the microarrays used in this study. The transcript corresponding to the zinc finger enco ding gene Watanabe et al. (2004) found upregulated, wa s not upregulated in the study described herein, and neither wa s the chlorophyll a/b binding transcript, the metallothioneinlike protein or the carbonic anhydrase transcript. In this study, like the st udy by Watanabe et al. (200 4 ) resistance gene family members were differentially expressed in silicon amended plans compared to control plants. For example, Os11g0625900 is downregulated in both C vs Si, and C vs P plants in this study. The level of downr egulation in silicon amended compared to control plants in this study (1.14 fold) is comparable to the leve l found by Watanabe et al. (2004 ) in silicon amended plants, but in response to pathogen infection it decreases 14.9 fold in this study. Compared to the results obtained by Rodrigues et al. (2005), this study confirms the involvement of chitinases in the defense response of rice after M. grisea inoculation, although

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109 the timing is different between the two studies. Rodrigues et al. (2005) did not see s ignificant chitinase transcript accumularion in northern blot analysis until 36 hours after inoculation in non amended plants, while in this study there is an increase already at 24 hours after inoculation. As in the study by Rodrigues et al. (2005) this i ncrease was not apparent in silicon amended plants. Again in agreement, this study showed that phenylalanine lyase and peroxidases are upregulated after pathogen infection of non amended plants. Regarding PR 1 gene expression no conclusions can be drawn b y comparing the two studies, since Rodrigues et al. (2005) did not see any difference at 24 hours after inoculation. Defense /stress related genes differentially regulated in the P vs SiP comparison are of particular interest because they identify the diff erences in gene expression after pathogen inoculation which is associated with the presence of silicon. Among these were genes potentially part of the ethylene signaling pathway, a gene encoding a thaumatin/pathogenesis related protein (Os12g0568 900) predi cted to be secreted (Nakai and H orton 1999 ), a class III peroxidase (Os07g0677500), and a number of transcription factors, and protein kinases that are not differentially expressed in the C vs P comparison. More than simply attenuating the plant response t o the pathogen as Fauteux et al. (2006) concluded in the Arabidopsis powdery mildew experiments, a substantially different pattern of expression was noted in this experiment. Not only did the Si vs SiP comparison have 440 differentially expressed genes les s than the C vs P comparison, the two comparisons had only 236 genes in common. In the rice rice blast system, silicon affected the interaction between host and pathogen at the molecular level Since a number of defense /stress response related genes were d ifferentially regulated, a possibility is that silicon amendment is responsible for preconditioning plants to react to stress.

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110 This seemed to be reflected in the fact that infection with M. grisea resulted in less than half the number of differentially exp ressed genes in silicon amended plants than in non amended plants (298 vs 738). There are several possibilities to interpret the response: 1) silicon attenuated the reaction to the pathogen infection by directly preventing differential expression of rice g enes, 2) genes differentially expressed in silicon amended plants acted directly on the pathogen effectors, attenuating the effect they have on the rice plant, which then indirectly resulted in less genes being differentially regulated, 3) targets of the p athogen effector genes may be turned off by silicon amendment, blocking the pathogens access to signal transduction pathways required for pathogenicity 4) genes differentially expressed in silicon amended plants may not require further differential regul ation upon pathogen infection These possibilities are not mutually exclusive. In conclusion, in rice 221 genes are differentially regulated when amended with silicon compared to control plants suggesting that silicon may be an integral part of rice physio logy, and that silicon might be essential for rice. Silicon amendment changes the rice response to rice blast infection at the gene transcription level, implying a role for silicon in one or more plant defense signaling pathways.

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111 T able 4 1 M icroarray ex periment treatments Treatment z Silicon amendment Pathogen inoculation C $ $ Si + $ P $ + SiP + + z Control plants (C) were not amended with silicon, nor inoculated with M. grisea Treatments consisted of plants amended with silicon (Si), inoculated wit h M. grisea (P), or both (SiP). Table 4 2 Number of up and down regulated genes unique for each comparison of treatments Treatment Comparison Upregulated Downregulated Total C Si 16 35 52 P SiP 29 25 54 C P 273 39 312 Si SiP 42 12 54 Table 4 3 Cate gories of differentially expressed gene s for each treatment comparison Up/ Downregulation C Si P SiP C P Si SiP Defense Up 9 6 59 30 Defense Down 16 8 13 2 Other Up 50 25 348 156 Other Down 45 74 48 14 Unknown Up 46 32 211 86 Unknown Down 55 41 59 10 Total 221 186 738 298

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112 Figure 4 1 The number of differentially expressed genes for each treatment comparison.

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113 Figure 4 2 Volcanoplot C vs Si. The difference of expression levels of each array spot is represented by a dot. The level of expressi on is plotted on the x axis as the log2 of the foldchange. Spots that have a higher expression level in silicon amended plants compared to control plants have a positive difference, those with a lower expression level have a negative difference. The vertic al lines represent 1/3 and 3 fold difference in expression. The horizontal line represents the cutoff point for declaring differences significant based on q, the adjusted P value for multiple tests (q & 0.001).

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114 Figure 4 3 Volcanoplot P vs SiP. The differe nce of expression levels of each array spot is represented by a dot. The level of expression is plotted on the x axis as the log2 of the foldchange. Spots that have a higher expression level in silicon amended plants compared to control plants have a posit ive difference, those with a lower expression level have a negative difference. The vertical lines represent 1/3 and 3 fold difference in expression. The horizontal line represents the cutoff point for declaring differences significant based on q, the adju sted P value for multiple tests (q & 0.001).

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115 Figure 4 4 Volcanoplot C vs P. The difference of expression levels of each array spot is represented by a dot. The level of expression is plotted on the x axis as the log2 of the foldchange. Spots that have a higher expression level in silicon amended plants compared to control plants have a positive difference, those with a lower expression level have a negative difference. The vertical lines represent 1/3 and 3 fold difference in expression. The horizontal li ne represents the cutoff point for declaring differences significant based on q, the adjusted P value for multiple tests (q & 0.001).

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116 Figure 4 5 Volcanoplot Si vs SiP. The difference of expression levels of each array spot is represented by a dot. The lev el of expression is plotted on the x axis as the log2 of the foldchange. Spots that have a higher expression level in silicon amended plants compared to control plants have a positive difference, those with a lower expression level have a negative differen ce. The vertical lines represent 1/3 and 3 fold difference in expression. The horizontal line represents the cutoff point for declaring differences significant based on q, the adjusted P value for multiple tests (q & 0.001).

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117 Figure 4 6 The distribution of differentially expressed genes for each of the treatment comparisons. P/S=pathogenicity/stress related genes, Oth=other genes, Unk=unknown genes, U=upregulated, D=downregulated.

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118 Figure 4 7 Number of unique and overlapping genes for each comparison combination.

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119 CHAPTER 5 CONCLUSION Silicon in O rnamentals A growing body of literature has reported on the beneficial effects of silicon in both the traditionally known accumulators of silicon, the monocotyledons (specifically graminaeceae), and dicotyl edons. The research described herein was to measure the silicon concentration in plants grown in bedding or containerized systems that received silicon in the growing medium. Frantz et al. (2005) described silicon uptake by New Guinea impatiens in hydropon ic systems. The results detailed in Chapter 2 however, imply that the uptake of silicon from nutrient solution in hydroponic systems is different from that in containerized systems with soilless medium. Locke et al. (2008) tested more than 30 floricultural crops, but found silicon accumulation only in zinnia, verbena, and sunflower. The experiments described in this work did not show a difference in silicon concentration in begonia and marigold in silicon amended plants compared to control plants; there was no evidence for a rate response. Although higher concentrations of silicon did occur when the plants were amended with AgSil25, from a practical point of view this is a not feasible technique. The high pH of AgSil25 increased the pH of the soilless medium to levels as high as 8.5, and the plants did not grow well, and often died. High pH may make micronutrients unavailable to plants by chemically converting the ions into plant unavailable forms. The results of these studies suggested that there might be a limit in the practical use of AgSil25. Application of AgSil25 would have advantages over the use of granular calcium silicate such as Excellerator, or the powdery source of calcium silicate Wollastonite. Both Excellerator and Wollastonite would need to be incorporated in the soilless medium before planting, while AgSil25 can be applied continuously through fertigation. Before AgSil25 can be used in such a

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120 manner, studies would need to be performed that use smaller applications than the level of 1.40 kg elem ental silicon/m 3 It is quite possible that the concentration of silicon needed to confer beneficial effects in ornamentals might be less if silicon is applied in a pre dissolved form such as potassium silicate, which is instantly available to the plant, a nd can be applied as a drench together with liquid fertilizer. Therefore, lower concentrations of potassium silicate in the form of AgSil25 ought to be tested and confirmed by directly measuring silicon in the plant sap. In addition, the best way to buffer the medium needs to be studied. To offset the effects of AgSil25, including the potassium added, the formulation of the fertilizer would need to be adjusted. The data support impatiens being an intermediate accumulator of silicon. The silicon concentratio n was higher in impatiens plants than in begonia and marigold and did show a small but statistically significant rate response. In addition, in an experiment where different sources of silicon were tested on impatiens, there was a 24% increase in silicon c oncentration. Additional experiments using impatiens with more replicates are necessary to confirm this conclusion. The ornamental grass Tigergrass ( Thysanolaena maxima ) did accumulate silicon, and had a statistically significant rate response. In both exp eriments, the rate response fit a quadratic model. The rate response curve for tigergrass was similar to those reported for turfgrasses (Datnoff and Nagata 1999; Datnoff and Rutherford 2003; Nanayakkara et al. 2008a,b). Tigergrass accumulated silicon to a level as high as 1.71 cg silicon/ g m dry weight with silicon amended at 1.87 kg elemental silicon/m 3 This is consistent with the fact that members of the family Poaceae such as barley (Williams and Vlamis 1957), rice (Datnoff et al. 2001), wheat ( Triticum aestivum L.; Dietrich et al. 2003) and the turfgrasses mentioned above, accumulate silicon.

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121 In conclusion, silicon amendment of begonia and marigold did not result in an increase in silicon concentration of the leaves in the context of resulting in marketa ble plants under the conditions used in this study. Impatiens did show a larger silicon concentration in silicon amended plants, thus although the results were inconsistent among experiments, impatiens could still be considered an intermediate accumulator of silicon. Tigergrass is an accumulator of silicon. Based on the silicon concentration observed for tigergrass and the rate response measured in this study, support the hypothesis that tigergrass is a silicon accumulator according to the categories propos ed by Ma et al. (2001). Exserohilum rostratum on Tigergrass A fungal pathogen, which causes a leaf spot disease on tigergrass, was isolated, characterized, and identified as Exserohilum rostratum a common pathogen of grasses, based on conidial morphology and the ITS1/4 sequence. Exserohilum belongs to what was formerly known as the Helminthosporium complex, a large genus that was separated into three genera (Sivanesan 1987). The three genera of anamorphs, largely coincide with three genera of teleomorps; a ll Exserohilum spp. for which a teleomorph has been identified, have one that belongs to the ascomycete genus Setosphaeria (Sivanesan 1987). Isolates of E rostratum have been reported as diseases on bermuda grass (Pratt and Brink 2007), and on johnson gra ss, broadleaf signal grass, and yellow foxtail (all three are volunteer grasses found in berm uda grass pastures; Pratt 2006; Pratt and Brink 2007). Increasing inoculum density resulted in increasing levels of disease severity, and a shortened incubation p eriod. At the highest inoculum density tested (10 5 conidia/ml), symptoms were visible within 12 hours after inoculation. The effect of silicon application to the growing medium of tigergrass in containers was investigated. Both disease severity and AUDPC ( area under disease progress curve) were

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122 significantly decreased with application of soluble silicon in the form of potassium silicate (AgSil25) as a drench to the containers twice a week at a rate equivalent to 700 kg elemental silicon/ha. Exserohilum rost ratum growth was completely inhibited in vitro when potassium silicate was added to V 8 juice agar at a rate of 277 mM silicon or higher. The inhibition was fungistatic, because after 2 weeks without any growth on the silicon amended agar plates, all the p lugs that were transferred to V 8 juice agar without potassium silicate grew normally. This might be an indication that soluble silicon in the plant plays a role in disease resistance of the host by affecting the ability of the pathogen to grow (fast). Sam uels et al. (1991) found that soluble silicon was essential for the beneficial effect against powdery mildew on cucumber, even when the levels of accumulated insoluble silicon in the leaves were high. Recent information suggests that soluble and insoluble silicon both contribute to the resistance of rice against rice blast (Datnoff et al. 2008). In the two experiments described in chapter 3, silicon did not affect the final disease severity. However, the control plants had significantly more disease for mos t of the experiments, resulting in a significantly decreased area under disease progress curve for the silicon treatments with respect to the control plants. In the first experiment, AgSil25 treated plants had an 87% lower AUDPC, while in the second experi ment it was 46% lower. Excellerator amended tigergrass had a 35% lower in AUDPC compared to control plants in the first experiment, and 34% in the second experiment. Wollastonite amended tigergrass had a 56% and 32% decrease in AUDPC compared to the contro l in the first and second experiment, respectively. In the first experiment, only the AUDPC of AgSil amended plants was significantly different than that of the control, while in the second experiment, all silicon amended plants regardless of treatment

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123 had a significantly decreased AUDPC compared to control plants. This leads to the conclusion that silicon indeed increases the resistance of tigergrass to E. rostratum infection. Silicon can be as effective in controlling plant disease as fungicides, but the combination of both is most effective (Datnoff et al. 1997). For brown spot and blast of rice, the integration of silicon amendment and fungicide application resulted in the greatest reduction of disease severity and progress (Datnoff and Rodrigues 2005). The interaction of the two control measures resulted in lower disease development. The combined effect of fungicide treatments and silicon amendment might be considered for culture of tigergrass, particularly in the nursery. Although a control program usin g different fungicides was used on tigergrass supplied for this study, the plants often arrived with high levels of infection. More research is necessary to study the effectiveness of a spray program combined with silicon, but there is some indication that this might be useful based on the data from this study. In conclusion, this part of the study confirmed that E. rostratum is the causal agent of tigergrass leaf spot. In addition, it was shown that silicon amendment decreases the area under disease progre ss curves compared to that of the control, so silicon amendment increases the resistance of tigergrass to E. rostratum The Transcriptional Response of Rice to the Silicon Pathogen Interaction The interaction of rice M. grisea with silicon amendment was investigated using 44k microarrays representing the entire rice genome. It was shown in this study that rice amended with silicon affects different levels of transcripts for 221 genes compared to non amended rice. A number of genes are known or suspected t o be involved in the plant pathogen response and imply that silicon amendment may serve to prime the rice pathogen response pathways. This diffuses any arguments that silicons only role in disease resistance is the deposition of an impenetrable layer in t he epidermal cells as a mechanical barrier.

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124 This finding contrast with the results of Fauteux et al. (2006) who found that silicon affected the transcript levels of only two Arabidopsis thaliana genes compared with unamended plants, and indicated that the role of silicon might be different between rice and Arabidopsis This difference may be more general, and may for example be due to the difference of silicons role between monocotyledons and dicotyledons. In the Arabidopsis powdery mildew interaction, the number of genes differentially regulated in response to the pathogen when the plants were amended with silicon was also smaller than when non amended plants were infected (Fauteux et al. 2006). The authors did not mention whether any of those differential ly expressed genes were unique for the interaction. These genes might be of interest for future research. Considering both theories of silicons role in disease resistance, and the evidence that has been presented in the literature, it appears that silicon plays a role at different levels. There is evidence for the mechanical barrier hypothesis (Carver et al. 1987; Kim et al. 2002; Park et al. 2006), and for an active role of silicon in the molecular signaling pathways that leads to resistance (Rodrigues et al. 2003a, 2004, 2005, this work); for the necessity of both soluble and insoluble silicon ( Datnoff et al. 2008; Samuels 1991; this work). None of these theories is mutually exclusive. It is quite possible that a mechanical barrier prevents and/or slows d own fungal penetration. During the penetration process the germ tube can locally dissolve the silica gel layer, the locally higher concentration of silicon can inhibit growth of the fungus, and silicon can serve as a signaling compound for the timely activ ation of a plant defense response. In conclusion, silicon amendment changes the basal level of gene of rice plants, and the rice response against rice blast infection by decreasing the number of differentially regulated gene. This confirms that silicon pla ys a role at the physiological level both in unchallenged and pathogen challenged rice plants.

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125 Table 5 1 Contributions to science for each chapter Chapter Contributions to scientific knowledge 2 Begonia and marigold did not accumulate more silicon if the soilless growing medium was amended with calcium silicate. Potassium silicate raised the pH of the growing medium to levels so high that begonia and marigold no longer grew. The data on impatiens weakly supported a rate response. Tigergrass accumula ted silicon in a rate dependent manner. Tigergrass tolerated the high medium pH better than begonia, impatiens, and marigold. 3 Tigergrass leaf spot is caused by Exserohilum rostratum (Drechsler) Leonard & Suggs. In vitro growth of E. rostratum is inh ibited by silicon amendment of the medium. Spray inoculation of E. rostratum resulted in symptoms as early as 12 hours after inoculation. Silicon amendment of the growing medium decreased the area under disease progress curve of E. rostratum on tigergr ass. 4 Silicon amendment changes the physiology of rice, changing the basal level of gene expression of the unchallenged rice plant. Silicon amendment attenuated the response of rice gene expression to inoculation with the rice blast pathogen Magnaporth e grisea

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126 APPENDIX EXPRESSION PROFILE O F DIFFERENTIALLY EXPRE SSED GENES

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127 Table A 1 Expression profile of defense and/or stress related genes G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 1 1 g 0 6 9 2 5 0 0 B a c t e r i a l b l i g h t r e s i s t a n c e p r o t e i n U 1 O s 0 1 g 0 9 6 3 2 0 0 P e r o x i d a s e B P 1 p r e c u r s o r U O s 0 1 g 0 3 7 8 1 0 0 P e r o x i d a s e p r e c u r s o r ( E C 1 1 1 1 7 ) U O s 1 1 g 0 6 0 8 3 0 0 B a r l e y s t e m r u s t r e s i s t a n c e p r o t e i n D O s 1 1 g 0 6 7 3 6 0 0 D i s e a s e r e s i s t a n c e p r o t e i n f a m i l y p r o t e i n D O s 0 3 g 0 2 6 6 3 0 0 H e a t s h o c k p r o t e i n H s p 2 0 d o m a i n c o n t a i n i n g p r o t e i n D O s 0 3 g 0 2 3 5 0 0 0 P e r o x i d a s e ( E C 1 1 1 1 7 ) D O s 1 2 g 0 4 9 1 8 0 0 T e r p e n e s y n t h a s e l i k e d o m a i n c o n t a i n i n g p r o t e i n D O s 1 0 g 0 1 9 1 3 0 0 T y p e 1 p a t h o g e n e s i s r e l a t e d p r o t e i n D O s 1 0 g 0 5 6 2 9 0 0 P a t h o g e n e s i s r e l a t e d t r a n s c r i p t i o n a l f a c t o r a n d E R F d o m a i n c o n t a i n i n g p r o t e i n U O s 0 7 g 0 6 7 7 5 0 0 P e r o x i d a s e P O C 1 U O s 1 2 g 0 5 6 8 9 0 0 T h a u m a t i n p a t h o g e n e s i s r e l a t e d f a m i l y p r o t e i n U O s 0 3 g 0 7 6 7 0 0 0 A l l e n e o x i d e s y n t h a s e ( E C 4 2 1 9 2 ) U O s 0 9 g 0 4 4 2 1 0 0 A v r 9 / C f 9 r a p i d l y e l i c i t e d p r o t e i n 2 6 4 U O s 0 3 g 0 3 3 1 7 0 0 A v r 9 / C f 9 r a p i d l y e l i c i t e d p r o t e i n 3 1 U O s 0 5 g 0 5 6 6 4 0 0 B l a s t a n d w o u n d i n g i n d u c e d m i t o g e n a c t i v a t e d p r o t e i n k i n a s e U O s 0 7 g 0 5 8 3 6 0 0 C h i t i n i n d u c i b l e g i b b e r e l l i n r e s p o n s i v e p r o t e i n U O s 0 2 g 0 6 0 5 9 0 0 C h i t i n a s e ( E C 3 2 1 1 4 ) A U O s 0 1 g 0 8 6 0 5 0 0 C h i t i n a s e ( E C 3 2 1 1 4 ) U O s 1 0 g 0 5 4 3 4 0 0 C h i t i n a s e ( E C 3 2 1 1 4 ) U O s 0 6 g 0 3 5 6 8 0 0 C l a s s I I I c h i t i n a s e h o m o l o g u e ( O s C h i b 3 H h ) ( F r a g m e n t ) U O s 0 4 g 0 5 1 4 6 0 0 D i s e a s e r e s i s t a n c e p r o t e i n f a m i l y p r o t e i n U O s 0 3 g 0 1 2 2 3 0 0 F l a v a n o n e 3 h y d r o x y l a s e l i k e p r o t e i n U O s 0 4 g 0 6 7 1 2 0 0 F l a v i n c o n t a i n i n g a m i n e o x i d a s e f a m i l y p r o t e i n U O s 0 4 g 0 4 3 0 6 0 0 H a r p i n i n d u c e d 1 d o m a i n c o n t a i n i n g p r o t e i n U O s 1 2 g 0 1 5 9 0 0 0 H a r p i n i n d u c e d 1 d o m a i n c o n t a i n i n g p r o t e i n U O s 0 4 g 0 6 6 7 6 0 0 H e a v y m e t a l t r a n s p o r t / d e t o x i f i c a t i o n p r o t e i n d o m a i n c o n t a i n i n g p r o t e i n U O s 0 2 g 0 5 9 2 4 0 0 H y p o x i a i n d u c e d p r o t e i n c o n s e r v e d r e g i o n f a m i l y p r o t e i n U O s 0 1 g 0 1 1 3 2 0 0 L R K 1 4 U O s 0 9 g 0 4 8 6 5 0 0 M u l t i p l e s t r e s s r e s p o n s i v e z i n c f i n g e r p r o t e i n U O s 0 6 g 0 7 0 7 8 0 0 N B S L R R d i s e a s e r e s i s t a n c e p r o t e i n h o m o l o g u e U

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128 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 4 g 0 5 5 0 2 0 0 P a t h o g e n e s i s r e l a t e d t r a n s c r i p t i o n a l f a c t o r a n d E R F d o m a i n c o n t a i n i n g p r o t e i n U O s 0 6 g 0 5 4 7 4 0 0 P e r o x i d a s e P 7 ( E C 1 1 1 1 7 ) ( T P 7 ) U O s 1 2 g 0 5 2 0 2 0 0 P h e n y l a l a n i n e a m m o n i a l y a s e ( E C 4 3 1 5 ) ( F r a g m e n t ) U O s 0 4 g 0 4 9 0 5 0 0 P t o k i n a s e i n t e r a c t o r 1 U O s 0 7 g 0 6 9 1 3 0 0 W o u n d i n d u c e d W I 1 2 f a m i l y p r o t e i n U O s 0 2 g 0 1 2 5 3 0 0 B a x i n h i b i t o r 1 ( B I 1 ) ( O s B I 1 ) U O s 0 1 g 0 8 5 5 6 0 0 H s 1 p r o 1 p r o t e i n U O s 1 1 g 0 7 0 4 8 0 0 M e m b r a n e p r o t e i n U O s 1 1 g 0 2 2 9 4 0 0 R P R 1 U O s 0 3 g 0 1 2 9 1 0 0 S e v e n t r a n s m e m b r a n e p r o t e i n M L O 2 U O s 0 1 g 0 2 0 5 9 0 0 P e r o x i d a s e 5 2 p r e c u r s o r ( E C 1 1 1 1 7 ) ( A t p e r o x P 5 2 ) ( A T P 4 9 ) D O s 0 3 g 0 3 4 7 9 0 0 T e r p e n o i d s y n t h a s e d o m a i n c o n t a i n i n g p r o t e i n D O s 0 1 g 0 7 1 3 2 0 0 B e t a 1 3 g l u c a n a s e p r e c u r s o r U O s 0 2 g 0 5 8 4 8 0 0 H e a v y m e t a l t r a n s p o r t / d e t o x i f i c a t i o n p r o t e i n d o m a i n c o n t a i n i n g p r o t e i n U O s 0 2 g 0 5 8 5 1 0 0 H e a v y m e t a l t r a n s p o r t / d e t o x i f i c a t i o n p r o t e i n d o m a i n c o n t a i n i n g p r o t e i n U O s 0 4 g 0 4 6 9 0 0 0 H e a v y m e t a l t r a n s p o r t / d e t o x i f i c a t i o n p r o t e i n d o m a i n c o n t a i n i n g p r o t e i n U O s 0 4 g 0 6 1 0 4 0 0 P a t h o g e n e s i s r e l a t e d t r a n s c r i p t i o n a l f a c t o r a n d E R F d o m a i n c o n t a i n i n g p r o t e i n U O s 0 7 g 0 1 0 4 1 0 0 P e r o x i d a s e 2 7 p r e c u r s o r ( E C 1 1 1 1 7 ) ( A t p e r o x P 2 7 ) ( P R X R 7 ) ( A T P 1 2 a ) U O s 0 8 g 0 5 3 9 7 0 0 P i b H 8 p r o t e i n U O s 0 7 g 0 6 3 6 6 0 0 P l a n t d i s e a s e r e s i s t a n c e r e s p o n s e p r o t e i n f a m i l y p r o t e i n D O s 0 4 g 0 6 6 2 6 0 0 F l a v a n o n e 3 h y d r o x y l a s e ( F r a g m e n t ) U D U D O s 1 1 g 0 6 8 4 1 0 0 D i s e a s e r e s i s t a n c e p r o t e i n f a m i l y p r o t e i n U U O s 1 1 g 0 6 8 6 4 0 0 D i s e a s e r e s i s t a n c e p r o t e i n f a m i l y p r o t e i n U U O s 1 1 g 0 6 8 6 5 0 0 D i s e a s e r e s i s t a n c e p r o t e i n f a m i l y p r o t e i n U U O s 0 1 g 0 1 1 4 3 0 0 L R K 1 4 U U O s 1 0 g 0 1 3 5 1 0 0 N B A R C d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 5 g 0 4 0 4 2 0 0 M e t h i o n i n e s u l f o x i d e r e d u c t a s e B d o m a i n c o n t a i n i n g p r o t e i n D U D U O s 0 4 g 0 4 9 3 6 0 0 C h i t i n b i n d i n g t y p e 1 d o m a i n c o n t a i n i n g p r o t e i n D D

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129 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 8 g 0 4 1 1 9 0 0 D i s e a s e r e s i s t a n c e p r o t e i n f a m i l y p r o t e i n D D O s 1 1 g 0 6 0 5 1 0 0 D i s e a s e r e s i s t a n c e p r o t e i n f a m i l y p r o t e i n D D O s 1 1 g 0 6 0 6 4 0 0 D i s e a s e r e s i s t a n c e p r o t e i n f a m i l y p r o t e i n D D O s 1 1 g 0 6 3 9 6 0 0 D i s e a s e r e s i s t a n c e p r o t e i n f a m i l y p r o t e i n D D O s 0 1 g 0 1 1 4 7 0 0 L R K 3 3 D D O s 0 1 g 0 9 6 2 7 0 0 P e r o x i d a s e 1 2 p r e c u r s o r ( E C 1 1 1 1 7 ) ( A t p e r o x P 1 2 ) ( P R X R 6 ) ( A T P 4 a ) D D O s 0 7 g 0 1 2 9 2 0 0 P R 1 a p r o t e i n D D O s 0 8 g 0 1 6 8 0 0 0 T e r p e n e s y n t h a s e m e t a l b i n d i n g d o m a i n c o n t a i n i n g p r o t e i n D D O s 0 5 g 0 3 7 5 4 0 0 ( 1 3 ; 1 4 ) b e t a g l u c a n a s e p r e c u r s o r ( E C 3 2 1 7 3 ) U D O s 0 9 g 0 3 1 9 8 0 0 T e r p e n o i d c y l a s e s / p r o t e i n p r e n y l t r a n s f e r a s e a l p h a a l p h a t o r o i d d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 2 g 0 6 2 6 6 0 0 P h e n y l a l a n i n e a m m o n i a l y a s e D U U O s 0 7 g 0 1 2 4 9 0 0 P R 1 a p r o t e i n D U U O s 0 7 g 0 1 2 6 1 0 0 P R 1 a p r o t e i n D U U O s 0 7 g 0 6 0 4 3 0 0 C O B R A p r o t e i n p r e c u r s o r ( C e l l e x p a n s i o n p r o t e i n ) D U U O s 0 1 g 0 9 6 8 8 0 0 A v r 9 / C f 9 r a p i d l y e l i c i t e d p r o t e i n 1 1 1 B D U O s 0 1 g 0 7 6 9 7 0 0 L p i m P t h 4 D U O s 0 2 g 0 1 2 1 7 0 0 T e r p e n e s y n t h a s e l i k e d o m a i n c o n t a i n i n g p r o t e i n D U O s 0 3 g 0 2 2 5 9 0 0 A l l e n e o x i d e s y n t h a s e ( E C 4 2 1 9 2 ) U U O s 0 7 g 0 5 4 5 8 0 0 C h i t i n i n d u c i b l e g i b b e r e l l i n r e s p o n s i v e p r o t e i n U U O s 0 3 g 0 7 4 8 5 0 0 F l a v o d o x i n / n i t r i c o x i d e s y n t h a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 1 g 0 8 6 4 3 0 0 H a r p i n i n d u c e d 1 d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 1 g 0 8 6 4 5 0 0 H a r p i n i n d u c e d 1 d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 7 g 0 2 5 1 2 0 0 H a r p i n i n d u c e d 1 d o m a i n c o n t a i n i n g p r o t e i n U U O s 1 1 g 0 1 3 0 4 0 0 H a r p i n i n d u c e d 1 d o m a i n c o n t a i n i n g p r o t e i n U U O s 1 2 g 0 1 2 7 2 0 0 H a r p i n i n d u c e d 1 d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 4 g 0 4 6 4 1 0 0 H e a v y m e t a l t r a n s p o r t / d e t o x i f i c a t i o n p r o t e i n d o m a i n c o n t a i n i n g p r o t e i n U U O s 1 1 g 0 2 2 9 3 0 0 N B S L R R d i s e a s e r e s i s t a n c e p r o t e i n h o m o l o g u e U U O s 0 7 g 0 1 2 9 3 0 0 P a t h o g e n e s i s r e l a t e d p r o t e i n 1 p r e c u r s o r U U O s 0 1 g 0 8 6 8 0 0 0 P a t h o g e n e s i s r e l a t e d t r a n s c r i p t i o n a l f a c t o r a n d E R F d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 1 g 0 9 6 3 0 0 0 P e r o x i d a s e B P 1 p r e c u r s o r U U O s 0 5 g 0 4 2 7 4 0 0 P h e n y l a l a n i n e a m m o n i a l y a s e ( E C 4 3 1 5 ) U U

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130 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 1 g 0 1 3 6 0 0 0 1 6 9 k D a c l a s s I h e a t s h o c k p r o t e i n U U O s 0 3 g 0 3 0 1 2 0 0 C O B R A l i k e p r o t e i n 7 p r e c u r s o r U U O s 0 2 g 0 5 6 2 6 0 0 M l o r e l a t e d p r o t e i n f a m i l y p r o t e i n U U 1 T r e a t m e n t c o m p a r i s o n s : C S i = c o n t r o l v s s i l i c o n a m e n d e d S i S i P = s i l i c o n a m e n d e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d C P = c o n t r o l v s p a t h o g e n i n o c u l a t e d P S i P = p a t h o g e n i n o c u l a t e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d U = u p r e g u l a t e d D = d o w n r e g u l a t e d D i f f e r e n t i a l r e g u l a t i o n i s r e p o r t e d w i t h r e s p e c t t o t h e t r e a t m e n t o n t h e l e f t o f t h e c o m p a r i s o n

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131 T a b l e A 2 E xpression profile of transcription factor encoding genes G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 3 g 0 3 7 9 3 0 0 B a s i c h e l i x l o o p h e l i x d i m e r i s a t i o n r e g i o n b H L H d o m a i n c o n t a i n i n g p r o t e i n U 1 O s 0 1 g 0 6 3 3 4 0 0 C B S d o m a i n c o n t a i n i n g p r o t e i n U O s 0 2 g 0 7 3 1 2 0 0 T r a n s c r i p t i o n f a c t o r M A D S 5 7 U O s 0 9 g 0 4 1 7 8 0 0 D N A b i n d i n g W R K Y d o m a i n c o n t a i n i n g p r o t e i n D O s 0 8 g 0 3 3 2 7 0 0 T r a n s a c t i n g t r a n s c r i p t i o n a l p r o t e i n I C P 0 ( I m m e d i a t e e a r l y p r o t e i n I E 1 1 0 ) D O s 0 2 g 0 6 9 5 2 0 0 P t y p e R 2 R 3 M y b p r o t e i n ( F r a g m e n t ) D O s 0 8 g 0 4 1 4 5 0 0 B a s i c h e l i x l o o p h e l i x d i m e r i s a t i o n r e g i o n b H L H d o m a i n c o n t a i n i n g p r o t e i n D O s 1 1 g 0 6 8 4 0 0 0 M y b D N A b i n d i n g d o m a i n c o n t a i n i n g p r o t e i n D O s 0 4 g 0 5 4 1 7 0 0 H o m e o b o x d o m a i n c o n t a i n i n g p r o t e i n D O s 0 2 g 0 6 7 3 5 0 0 B a s i c h e l i x l o o p h e l i x d i m e r i s a t i o n r e g i o n b H L H d o m a i n c o n t a i n i n g p r o t e i n U O s 0 4 g 0 6 3 1 6 0 0 B a s i c h e l i x l o o p h e l i x d i m e r i s a t i o n r e g i o n b H L H d o m a i n c o n t a i n i n g p r o t e i n U O s 0 8 g 0 4 9 0 0 0 0 B a s i c h e l i x l o o p h e l i x d i m e r i s a t i o n r e g i o n b H L H d o m a i n c o n t a i n i n g p r o t e i n U O s 0 7 g 0 2 8 7 0 0 0 C y c l i n l i k e F b o x d o m a i n c o n t a i n i n g p r o t e i n U O s 0 3 g 0 2 0 3 8 0 0 C y c l i n N t e r m i n a l d o m a i n c o n t a i n i n g p r o t e i n U O s 0 2 g 0 6 1 8 4 0 0 M Y B 8 p r o t e i n U O s 1 0 g 0 5 7 7 6 0 0 T r a n s c r i p t i o n f a c t o r j u m o n j i j m j C d o m a i n c o n t a i n i n g p r o t e i n U O s 0 5 g 0 4 4 2 4 0 0 T r a n s c r i p t i o n f a c t o r M Y B S 3 U O s 0 1 g 0 1 8 5 9 0 0 W R K Y t r a n s c r i p t i o n f a c t o r 1 ( Z n d e p e n d e n t a c t i v a t o r p r o t e i n 1 ) ( T r a n s c r i p t i o n f a c t o r Z A P 1 ) U O s 0 1 g 0 2 4 6 7 0 0 W R K Y t r a n s c r i p t i o n f a c t o r 1 U O s 0 6 g 0 6 4 9 0 0 0 W R K Y t r a n s c r i p t i o n f a c t o r 2 8 U O s 0 5 g 0 5 8 3 0 0 0 W R K Y t r a n s c r i p t i o n f a c t o r 3 4 U O s 0 4 g 0 3 9 5 8 0 0 Z I M d o m a i n c o n t a i n i n g p r o t e i n U O s 0 9 g 0 4 3 9 2 0 0 Z I M d o m a i n c o n t a i n i n g p r o t e i n U O s 0 1 g 0 8 5 9 1 0 0 Z i n c f i n g e r l i k e p r o t e i n U O s 0 3 g 0 3 0 2 2 0 0 Z n f i n g e r l i k e P H D f i n g e r d o m a i n c o n t a i n i n g p r o t e i n U O s 0 2 g 0 6 4 6 2 0 0 Z n f i n g e r B b o x d o m a i n c o n t a i n i n g p r o t e i n U O s 0 3 g 0 6 5 9 4 0 0 Z n f i n g e r C C H C t y p e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 8 g 0 4 9 0 1 0 0 Z n f i n g e r D o f t y p e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 2 g 0 5 5 9 8 0 0 Z n f i n g e r R I N G d o m a i n c o n t a i n i n g p r o t e i n U O s 0 3 g 0 7 2 3 0 0 0 G R A S t r a n s c r i p t i o n f a c t o r d o m a i n c o n t a i n i n g p r o t e i n U O s 0 5 g 0 5 6 0 6 0 0 H o m e o d o m a i n l i k e c o n t a i n i n g p r o t e i n U O s 0 9 g 0 4 8 3 6 0 0 T r a n s c r i p t i o n f a c t o r j u m o n j i j m j C d o m a i n c o n t a i n i n g p r o t e i n U

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132 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 6 g 0 6 3 7 5 0 0 T y p i c a l P t y p e R 2 R 3 M y b p r o t e i n ( F r a g m e n t ) U O s 0 1 g 0 5 4 2 7 0 0 B a s i c l e u c i n e z i p p e r ( b Z I P ) t r a n s c r i p t i o n f a c t o r d o m a i n c o n t a i n i n g p r o t e i n D O s 0 1 g 0 6 4 7 0 0 0 C y c l i n l i k e F b o x d o m a i n c o n t a i n i n g p r o t e i n D O s 1 0 g 0 1 3 3 1 0 0 C y c l i n l i k e F b o x d o m a i n c o n t a i n i n g p r o t e i n D O s 1 1 g 0 2 4 6 2 0 0 C y c l i n l i k e F b o x d o m a i n c o n t a i n i n g p r o t e i n D O s 0 6 g 0 1 4 0 4 0 0 D N A b i n d i n g p r o t e i n ( H o m e o d o m a i n l e u c i n e z i p p e r t r a n s c r i p t i o n f a c t o r ) D O s 0 4 g 0 6 1 3 0 0 0 Z i n c t r a n s p o r t e r 1 p r e c u r s o r ( Z R T / I R T l i k e p r o t e i n 1 ) D O s 0 5 g 0 1 9 5 2 0 0 Z n f i n g e r C x 8 C x 5 C x 3 H t y p e d o m a i n c o n t a i n i n g p r o t e i n D O s 0 9 g 0 2 4 3 2 0 0 Z n f i n g e r R I N G d o m a i n c o n t a i n i n g p r o t e i n D O s 0 2 g 0 7 3 2 6 0 0 T y p i c a l P t y p e R 2 R 3 M y b p r o t e i n ( F r a g m e n t ) D O s 0 4 g 0 3 8 5 6 0 0 C y c l i n l i k e F b o x d o m a i n c o n t a i n i n g p r o t e i n U O s 1 1 g 0 6 6 5 6 0 0 H e l i x t u r n h e l i x F i s t y p e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 1 g 0 9 5 2 8 0 0 B a s i c h e l i x l o o p h e l i x d i m e r i s a t i o n r e g i o n b H L H d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 2 g 0 6 7 7 3 0 0 C R T / D R E b i n d i n g f a c t o r 1 U U U O s 0 4 g 0 5 7 2 4 0 0 C R T / D R E b i n d i n g f a c t o r 1 U U U O s 0 1 g 0 8 2 4 7 0 0 C y c l i n l i k e F b o x d o m a i n c o n t a i n i n g p r o t e i n U U O s 1 1 g 0 5 3 9 6 0 0 C y c l i n l i k e F b o x d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 1 g 0 1 2 7 4 0 0 M y b D N A b i n d i n g d o m a i n c o n t a i n i n g p r o t e i n U U O s 1 1 g 0 6 8 5 6 0 0 W R K Y t r a n s c r i p t i o n f a c t o r 4 1 U U O s 1 1 g 0 6 8 5 7 0 0 W R K Y t r a n s c r i p t i o n f a c t o r 6 1 U U O s 0 1 g 0 1 4 7 7 0 0 X S z i n c f i n g e r d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 8 g 0 1 9 7 5 0 0 C y c l i n l i k e F b o x d o m a i n c o n t a i n i n g p r o t e i n D D O s 0 1 g 0 8 7 1 2 0 0 Z n f i n g e r C 2 H 2 t y p e d o m a i n c o n t a i n i n g p r o t e i n D D O s 0 4 g 0 3 0 1 5 0 0 B a s i c h e l i x l o o p h e l i x d i m e r i s a t i o n r e g i o n b H L H d o m a i n c o n t a i n i n g p r o t e i n D U U O s 0 1 g 0 8 6 3 3 0 0 M y b D N A b i n d i n g d o m a i n c o n t a i n i n g p r o t e i n D U U O s 0 1 g 0 7 0 5 7 0 0 T r a n s c r i p t i o n f a c t o r I C E 1 ( I n d u c e r o f C B F e x p r e s s i o n 1 ) ( B a s i c H L H p r o t e i n 1 1 6 ) D U U O s 0 3 g 0 1 8 0 8 0 0 Z I M d o m a i n c o n t a i n i n g p r o t e i n D U U O s 0 3 g 0 1 8 1 1 0 0 Z I M d o m a i n c o n t a i n i n g p r o t e i n D U U O s 0 2 g 0 7 5 9 4 0 0 Z n f i n g e r R I N G d o m a i n c o n t a i n i n g p r o t e i n D U U O s 0 4 g 0 4 9 3 1 0 0 B a s i c h e l i x l o o p h e l i x d i m e r i s a t i o n r e g i o n b H L H d o m a i n c o n t a i n i n g p r o t e i n D U O s 0 6 g 0 1 6 4 4 0 0 B a s i c h e l i x l o o p h e l i x d i m e r i s a t i o n r e g i o n b H L H d o m a i n c o n t a i n i n g p r o t e i n D U O s 0 9 g 0 4 1 7 6 0 0 D N A b i n d i n g W R K Y d o m a i n c o n t a i n i n g p r o t e i n D U O s 0 2 g 0 6 4 1 3 0 0 M y b D N A b i n d i n g d o m a i n c o n t a i n i n g p r o t e i n D U

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133 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 5 g 0 4 4 4 2 0 0 Z n f i n g e r C 2 H 2 t y p e d o m a i n c o n t a i n i n g p r o t e i n D U O s 0 3 g 0 7 4 1 1 0 0 B a s i c h e l i x l o o p h e l i x d i m e r i s a t i o n r e g i o n b H L H d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 7 g 0 5 6 1 3 0 0 C y c l i n l i k e F b o x d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 9 g 0 3 4 1 5 0 0 C y c l i n l i k e F b o x d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 1 g 0 8 2 1 6 0 0 D N A b i n d i n g W R K Y d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 4 g 0 5 1 7 1 0 0 M y b p r o t e i n U U O s 0 3 g 0 3 1 5 4 0 0 M Y B r e l a t e d p r o t e i n 3 4 0 U U O s 0 2 g 0 6 2 4 3 0 0 M Y B 1 p r o t e i n U U O s 0 4 g 0 4 1 6 1 0 0 T r a n s c r i p t i o n f a c t o r E 2 F / d i m e r i s a t i o n p a r t n e r ( T D P ) f a m i l y p r o t e i n U U O s 0 5 g 0 4 7 3 3 0 0 T r a n s c r i p t i o n a l f a c t o r T I N Y U U O s 0 1 g 0 8 2 6 4 0 0 W R K Y t r a n s c r i p t i o n f a c t o r 2 4 U U O s 0 2 g 0 4 6 2 8 0 0 W R K Y t r a n s c r i p t i o n f a c t o r 4 2 ( T r a n s c r i p t i o n f a c t o r W R K Y 0 2 ) U U O s 0 2 g 0 1 8 1 3 0 0 W R K Y t r a n s c r i p t i o n f a c t o r 7 1 ( T r a n s c r i p t i o n f a c t o r W R K Y 0 9 ) U U O s 0 3 g 0 4 0 2 8 0 0 Z I M d o m a i n c o n t a i n i n g p r o t e i n U U O s 1 0 g 0 3 9 1 4 0 0 Z I M d o m a i n c o n t a i n i n g p r o t e i n U U O s 1 0 g 0 3 9 2 4 0 0 Z I M d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 9 g 0 3 8 5 7 0 0 Z n f i n g e r A N 1 l i k e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 3 g 0 4 3 7 2 0 0 Z n f i n g e r C 2 H 2 t y p e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 2 g 0 6 8 2 3 0 0 Z n f i n g e r R I N G d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 3 g 0 8 2 0 4 0 0 Z P T 2 1 3 U U O s 1 2 g 0 1 3 9 4 0 0 T w o c o m p o n e n t r e s p o n s e r e g u l a t o r A R R 1 7 U U O s 1 1 g 0 1 4 3 3 0 0 T y p e A r e s p o n s e r e g u l a t o r U U O s 0 4 g 0 6 7 3 3 0 0 Z m R R 2 p r o t e i n ( R e s p o n s e r e g u l a t o r 2 ) U U O s 0 4 g 0 5 8 3 9 0 0 M y b D N A b i n d i n g d o m a i n c o n t a i n i n g p r o t e i n D D O s 0 7 g 0 6 3 1 2 0 0 Z n f i n g e r R I N G d o m a i n c o n t a i n i n g p r o t e i n D D 1 T r e a t m e n t c o m p a r i s o n s : C S i = c o n t r o l v s s i l i c o n a m e n d e d S i S i P = s i l i c o n a m e n d e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d C P = c o n t r o l v s p a t h o g e n i n o c u l a t e d P S i P = p a t h o g e n i n o c u l a t e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d U = u p r e g u l a t e d D = d o w n r e g u l a t e d D i f f e r e n t i a l r e g u l a t i o n i s r e p o r t e d w i t h r e s p e c t t o t h e t r e a t m e n t o n t h e l e f t o f t h e c o m p a r i s o n

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134 Table A 3 E xpression profile of transporter encoding genes G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 1 g 0 8 7 1 6 0 0 T G F b e t a r e c e p t o r t y p e I / I I e x t r a c e l l u l a r r e g i o n f a m i l y p r o t e i n U 1 O s 0 2 g 0 5 5 0 8 0 0 A m m o n i u m t r a n s p o r t e r U O s 0 5 g 0 3 8 4 6 0 0 A B C t r a n s p o r t e r r e l a t e d d o m a i n c o n t a i n i n g p r o t e i n U O s 0 1 g 0 9 3 0 4 0 0 K + p o t a s s i u m t r a n s p o r t e r f a m i l y p r o t e i n U O s 0 1 g 0 7 5 9 9 0 0 P e r m e a s e 1 U O s 0 9 g 0 4 8 4 9 0 0 S o d i u m d i c a r b o x y l a t e c o t r a n s p o r t e r l i k e U O s 1 2 g 0 2 3 1 0 0 0 T G F b e t a r e c e p t o r t y p e I / I I e x t r a c e l l u l a r r e g i o n f a m i l y p r o t e i n D O s 0 7 g 0 2 5 8 4 0 0 M e t a l t r a n s p o r t e r N r a m p 6 ( A t N r a m p 6 ) U U O s 0 2 g 0 5 2 8 9 0 0 P D R 9 A B C t r a n s p o r t e r D D O s 0 1 g 0 1 8 9 1 0 0 T P R l i k e d o m a i n c o n t a i n i n g p r o t e i n D D O s 0 8 g 0 3 8 4 5 0 0 P D R l i k e A B C t r a n s p o r t e r ( P D R 3 A B C t r a n s p o r t e r ) U U 1 T r e a t m e n t c o m p a r i s o n s : C S i = c o n t r o l v s s i l i c o n a m e n d e d S i S i P = s i l i c o n a m e n d e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d C P = c o n t r o l v s p a t h o g e n i n o c u l a t e d P S i P = p a t h o g e n i n o c u l a t e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d U = u p r e g u l a t e d D = d o w n r e g u l a t e d D i f f e r e n t i a l r e g u l a t i o n i s r e p o r t e d w i t h r e s p e c t t o t h e t r e a t m e n t o n t h e l e f t o f t h e c o m p a r i s o n

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135 T a b l e A 4 E xpression profile of hormone pathway related genes G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 4 g 0 5 1 1 2 0 0 E F A 2 7 f o r E F h a n d a b s c i s i c a c i d 2 7 k D D 1 O s 0 7 g 0 6 7 4 8 0 0 A P 2 d o m a i n c o n t a i n i n g p r o t e i n R A P 2 2 ( F r a g m e n t ) U O s 0 6 g 0 2 2 5 3 0 0 B R A S S I N O S T E R O I D I N S E N S I T I V E 1 a s s o c i a t e d r e c e p t o r k i n a s e 1 p r e c u r s o r ( E C 2 7 1 3 7 ) U O s 0 7 g 0 6 2 2 0 0 0 A b s c i s i c a c i d i n d u c i b l e p r o t e i n k i n a s e ( E C 2 7 1 ) ( F r a g m e n t ) U O s 0 6 g 0 5 4 3 4 0 0 C B L i n t e r a c t i n g p r o t e i n k i n a s e 1 1 ( F r a g m e n t ) D O s 0 4 g 0 6 6 9 2 0 0 E t h y l e n e r e s p o n s e f a c t o r 3 U O s 0 5 g 0 4 9 7 3 0 0 E t h y l e n e r e s p o n s i v e e l e m e n t b i n d i n g f a c t o r 5 ( A t E R F 5 ) U O s 0 1 g 0 6 7 5 8 0 0 N o a p i c a l m e r i s t e m ( N A M ) p r o t e i n d o m a i n c o n t a i n i n g p r o t e i n U O s 0 2 g 0 5 7 9 0 0 0 N o a p i c a l m e r i s t e m ( N A M ) p r o t e i n d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 3 g 0 3 2 4 2 0 0 E I L 3 U U O s 0 8 g 0 4 7 4 0 0 0 A P 2 d o m a i n c o n t a i n i n g p r o t e i n R A P 2 6 ( F r a g m e n t ) D U U O s 0 6 g 0 1 2 7 1 0 0 C B F l i k e p r o t e i n D U U O s 0 1 g 0 7 0 6 9 0 0 A u x i n c o n j u g a t e h y d r o l a s e ( I L L 5 ) D U O s 0 8 g 0 4 5 2 5 0 0 A u x i n r e s p o n s i v e S A U R p r o t e i n f a m i l y p r o t e i n D U O s 0 1 g 0 1 9 2 9 0 0 A C C s y n t h a s e ( E C 4 1 1 1 4 ) ( F r a g m e n t ) U U O s 0 4 g 0 5 7 8 0 0 0 A C C s y n t h a s e ( E C 4 4 1 1 4 ) U U O s 0 9 g 0 4 5 7 9 0 0 A P 2 d o m a i n c o n t a i n i n g p r o t e i n R A P 2 6 ( F r a g m e n t ) U U O s 0 1 g 0 1 4 1 0 0 0 A P 2 d o m a i n c o n t a i n i n g p r o t e i n R A P 2 8 ( F r a g m e n t ) U U O s 0 5 g 0 1 2 7 3 0 0 C y t o k i n i n r e g u l a t e d k i n a s e 1 U U O s 0 1 g 0 2 2 4 1 0 0 E t h y l e n e r e s p o n s i v e e l e m e n t b i n d i n g f a c t o r U U O s 0 1 g 0 8 6 2 8 0 0 N o a p i c a l m e r i s t e m ( N A M ) p r o t e i n d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 3 g 0 1 3 3 0 0 0 N o a p i c a l m e r i s t e m ( N A M ) p r o t e i n d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 5 g 0 4 4 2 7 0 0 N o a p i c a l m e r i s t e m ( N A M ) p r o t e i n d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 9 g 0 5 2 2 0 0 0 C B F l i k e p r o t e i n U U O s 0 1 g 0 2 0 6 7 0 0 C B L i n t e r a c t i n g p r o t e i n k i n a s e 2 D D 1 T r e a t m e n t c o m p a r i s o n s : C S i = c o n t r o l v s s i l i c o n a m e n d e d S i S i P = s i l i c o n a m e n d e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d C P = c o n t r o l v s p a t h o g e n i n o c u l a t e d P S i P = p a t h o g e n i n o c u l a t e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d U = u p r e g u l a t e d D = d o w n r e g u l a t e d D i f f e r e n t i a l r e g u l a t i o n i s r e p o r t e d w i t h r e s p e c t t o t h e t r e a t m e n t o n t h e l e f t o f t h e c o m p a r i s o n

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136 Table A 5 E xpression profile of housekeeping genes G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 1 2 g 0 2 2 7 4 0 0 A l l y l a l c o h o l d e h y d r o g e n a s e U 1 O s 0 3 g 0 2 2 6 4 0 0 C a t i o n d i f f u s i o n f a c i l i t a t o r 8 U O s 0 1 g 0 8 9 8 5 0 0 P a t a t i n l i k e p r o t e i n 2 ( F r a g m e n t ) U O s 0 9 g 0 1 1 0 3 0 0 P u t a t i v e c y c l a s e f a m i l y p r o t e i n D O s 0 8 g 0 1 1 2 3 0 0 T r a n s f e r a s e f a m i l y p r o t e i n D O s 1 0 g 0 1 5 4 7 0 0 C y c l o p h i l i n D i c y p 2 D O s 0 8 g 0 1 5 5 7 0 0 D N A d i r e c t e d R N A p o l y m e r a s e ( E C 2 7 7 6 ) l a r g e s t c h a i n ( I s o f o r m B 1 ) l i k e p r o t e i n D O s 1 1 g 0 1 9 4 8 0 0 D N A d i r e c t e d R N A p o l y m e r a s e I I 7 6 k D a p o l y p e p t i d e D O s 1 1 g 0 1 0 6 7 0 0 F e r r i t i n 1 c h l o r o p l a s t p r e c u r s o r ( Z m F e r 1 ) D O s 1 2 g 0 1 0 6 0 0 0 F e r r i t i n 1 c h l o r o p l a s t p r e c u r s o r ( Z m F e r 1 ) D O s 1 2 g 0 2 5 8 7 0 0 M u l t i c o p p e r o x i d a s e t y p e 1 d o m a i n c o n t a i n i n g p r o t e i n D O s 0 1 g 0 7 7 0 2 0 0 T y r o s i n e d e c a r b o x y l a s e 1 ( E C 4 1 1 2 5 ) ( E L I 5 ) ( F r a g m e n t ) D O s 0 1 g 0 8 1 4 1 0 0 P l a n t l i p i d t r a n s f e r / s e e d s t o r a g e / t r y p s i n a l p h a a m y l a s e i n h i b i t o r d o m a i n c o n t a i n i n g p r o t e i n U O s 0 1 g 0 6 3 6 4 0 0 A l p h a / b e t a h y d r o l a s e f a m i l y p r o t e i n U O s 1 0 g 0 5 3 2 2 0 0 A l p h a / b e t a h y d r o l a s e f a m i l y p r o t e i n U O s 0 3 g 0 6 6 4 4 0 0 F i b r o i n U O s 1 2 g 0 6 3 0 6 0 0 F l a g e l l i f o r m s i l k p r o t e i n ( F r a g m e n t ) U O s 0 5 g 0 5 1 8 3 0 0 L i p o l y t i c e n z y m e G D S L f a m i l y p r o t e i n U O s 0 6 g 0 2 5 7 6 0 0 L i p o l y t i c e n z y m e G D S L f a m i l y p r o t e i n U O s 0 7 g 0 6 6 8 3 0 0 L i p o l y t i c e n z y m e G D S L f a m i l y p r o t e i n U O s 0 7 g 0 1 1 9 4 0 0 P e c t i n e s t e r a s e l i k e p r o t e i n U O s 0 9 g 0 5 4 8 2 0 0 P e p t i d o g l y c a n b i n d i n g L y s M d o m a i n c o n t a i n i n g p r o t e i n U O s 0 4 g 0 5 6 1 5 0 0 P r o l y l e n d o p e p t i d a s e ( E C 3 4 2 1 2 6 ) ( P o s t p r o l i n e c l e a v i n g e n z y m e ) ( P E ) U O s 0 4 g 0 4 4 7 7 0 0 N A D ( P ) H d e p e n d e n t 6 d e o x y c h a l c o n e s y n t h a s e ( E C 1 1 ) D O s 0 8 g 0 4 0 9 1 0 0 T r e h a l o s e 6 p h o s p h a t e p h o s p h a t a s e D O s 0 5 g 0 5 2 7 0 0 0 U D P g l u c u r o n o s y l / U D P g l u c o s y l t r a n s f e r a s e f a m i l y p r o t e i n D O s 0 4 g 0 6 0 4 2 0 0 X y l o g l u c a n e n d o t r a n s g l y c o s y l a s e p r e c u r s o r D O s 0 4 g 0 1 8 2 2 0 0 2 O G F e ( I I ) o x y g e n a s e d o m a i n c o n t a i n i n g p r o t e i n D O s 0 1 g 0 9 4 5 7 0 0 A m i n o a c i d / p o l y a m i n e t r a n s p o r t e r I f a m i l y p r o t e i n D O s 0 3 g 0 7 9 0 5 0 0 E s t e r a s e / l i p a s e / t h i o e s t e r a s e d o m a i n c o n t a i n i n g p r o t e i n D

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137 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 1 g 0 8 5 8 2 0 0 D E A D / H ( A s p G l u A l a A s p / H i s ) b o x p o l y p e p t i d e 1 6 D O s 0 6 g 0 7 2 5 2 0 0 L i p o l y t i c e n z y m e G D S L f a m i l y p r o t e i n D O s 1 0 g 0 3 9 3 8 0 0 L i p o l y t i c e n z y m e G D S L f a m i l y p r o t e i n D O s 1 2 g 0 6 1 7 4 0 0 V i v i p a r o u s 1 4 D O s 0 2 g 0 1 8 0 7 0 0 C i n n a m o y l C o A r e d u c t a s e ( E C 1 2 1 4 4 ) U O s 0 3 g 0 1 7 1 6 0 0 G a l a c t o s e o x i d a s e c e n t r a l d o m a i n c o n t a i n i n g p r o t e i n U O s 0 8 g 0 2 3 1 4 0 0 G e r m i n f a m i l y p r o t e i n U O s 0 8 g 0 1 8 8 9 0 0 G e r m i n l i k e p r o t e i n p r e c u r s o r U O s 0 8 g 0 1 8 9 1 0 0 G e r m i n l i k e p r o t e i n p r e c u r s o r U O s 0 7 g 0 5 2 3 4 0 0 G l u c o s e 6 p h o s p h a t e / p h o s p h a t e t r a n s l o c a t o r p r e c u r s o r U O s 1 2 g 0 2 8 3 4 0 0 G l u t e l i n f a m i l y p r o t e i n U O s 0 2 g 0 5 8 8 5 0 0 G l y c e r o p h o s p h o r y l d i e s t e r p h o s p h o d i e s t e r a s e f a m i l y p r o t e i n U O s 0 8 g 0 4 4 5 7 0 0 G l y c o s y l t r a n s f e r a s e f a m i l y 2 0 d o m a i n c o n t a i n i n g p r o t e i n U O s 0 3 g 0 8 0 3 6 0 0 G l y c o s y l t r a n s f e r a s e f a m i l y 3 1 p r o t e i n U O s 0 9 g 0 4 5 2 9 0 0 G l y c o s y l t r a n s f e r a s e f a m i l y 3 1 p r o t e i n U O s 0 6 g 0 5 6 1 0 0 0 M y o i n o s i t o l o x y g e n a s e U O s 0 2 g 0 7 7 0 8 0 0 N i t r a t e r e d u c t a s e [ N A D ( P ) H ] ( E C 1 7 1 2 ) U O s 0 6 g 0 6 0 4 2 0 0 P h o s p h o l i p a s e D U O s 0 7 g 0 2 9 0 5 0 0 P l a n t l i p i d t r a n s f e r / s e e d s t o r a g e / t r y p s i n a l p h a a m y l a s e i n h i b i t o r d o m a i n c o n t a i n i n g p r o t e i n U O s 0 3 g 0 7 5 8 5 0 0 P l a s t o c y a n i n l i k e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 8 g 0 4 8 2 7 0 0 P l a s t o c y a n i n l i k e d o m a i n c o n t a i n i n g p r o t e i n U O s 1 1 g 0 4 6 0 7 0 0 P r o t e i n p r e n y l t r a n s f e r a s e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 2 g 0 5 7 2 4 0 0 R i b o f l a v i n b i o s y n t h e s i s p r o t e i n r i b A c h l o r o p l a s t p r e c u r s o r U O s 0 4 g 0 5 9 4 4 0 0 R N A b i n d i n g r e g i o n R N P 1 ( R N A r e c o g n i t i o n m o t i f ) d o m a i n c o n t a i n i n g p r o t e i n U O s 0 3 g 0 2 4 1 9 0 0 S e n e s c e n c e a s s o c i a t e d p r o t e i n 1 2 U O s 0 7 g 0 5 8 2 4 0 0 S o r b i t o l t r a n s p o r t e r U O s 0 5 g 0 4 4 9 2 0 0 T r a n s f e r a s e f a m i l y p r o t e i n U O s 0 5 g 0 1 2 8 9 0 0 T r e h a l o s e p h o s p h a t a s e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 3 g 0 2 8 0 8 0 0 U D P g l u c u r o n i c a c i d d e c a r b o x y l a s e U O s 0 6 g 0 5 9 3 2 0 0 U D P g l u c u r o n o s y l / U D P g l u c o s y l t r a n s f e r a s e f a m i l y p r o t e i n U O s 0 4 g 0 6 8 3 7 0 0 4 c o u m a r a t e C o A l i g a s e l i k e p r o t e i n ( A d e n o s i n e m o n o p h o s p h a t e b i n d i n g p r o t e i n 3 A M P B P 3 ) U

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138 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 3 g 0 4 1 3 1 0 0 A C R 4 U O s 0 6 g 0 1 4 3 4 0 0 A c y l A C P t h i o e s t e r a s e U O s 0 6 g 0 5 5 6 0 0 0 A m i n o a c i d c a r r i e r ( F r a g m e n t ) U O s 1 2 g 0 1 8 1 6 0 0 A m i n o a c i d / p o l y a m i n e t r a n s p o r t e r I I f a m i l y p r o t e i n U O s 0 4 g 0 4 6 3 5 0 0 A n t h r a n i l a t e s y n t h a s e b e t a s u b u n i t ( E C 4 1 3 2 7 ) ( A t 1 g 2 5 2 2 0 ) U O s 0 3 g 0 1 5 4 1 0 0 A r o m a t i c r i n g h y d r o x y l a s e f a m i l y p r o t e i n U O s 0 1 g 0 6 6 3 4 0 0 A s p a r t i c p r o t e a s e ( F r a g m e n t ) U O s 0 4 g 0 5 7 8 4 0 0 B e t a r i n g h y d r o x y l a s e ( F r a g m e n t ) U O s 0 1 g 0 2 7 0 3 0 0 C a t i o n i c p e r o x i d a s e i s o z y m e 4 0 K p r e c u r s o r U O s 0 4 g 0 4 9 7 2 0 0 C e l l u l a s e p r e c u r s o r ( E n d o 1 4 b e t a D g l u c a n a s e K O R R I G A N ) ( E C 3 2 1 4 ) U O s 0 7 g 0 6 2 1 6 0 0 C y t o c h r o m e c o x i d a s e p o l y p e p t i d e V I b ( F r a g m e n t ) U O s 0 1 g 0 7 6 0 0 0 0 D y n e i n 8 k D a l i g h t c h a i n f l a g e l l a r o u t e r a r m U O s 0 4 g 0 4 6 2 6 0 0 D y n e i n l i g h t c h a i n t y p e 1 f a m i l y p r o t e i n U O s 0 6 g 0 2 1 4 3 0 0 E s t e r a s e / l i p a s e / t h i o e s t e r a s e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 7 g 0 5 6 4 5 0 0 F A D d e p e n d e n t p y r i d i n e n u c l e o t i d e d i s u l p h i d e o x i d o r e d u c t a s e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 5 g 0 4 4 7 7 0 0 F e r r i t i n / r i b o n u c l e o t i d e r e d u c t a s e l i k e f a m i l y p r o t e i n U O s 0 1 g 0 6 0 0 5 0 0 H A D s u p e r f a m i l y s u b f a m i l y I B h y d r o l a s e h y p o t h e t i c a l 1 p r o t e i n U O s 0 1 g 0 9 0 8 7 0 0 H e t e r o g e n e o u s n u c l e a r r i b o n u c l e o p r o t e i n A 2 h o m o l o g 1 ( h n R N P A 2 ( A ) ) U O s 0 1 g 0 1 2 7 9 0 0 M a n n o s e 6 p h o s p h a t e i s o m e r a s e t y p e I f a m i l y p r o t e i n U O s 1 1 g 0 6 8 6 0 0 0 E n / S p m l i k e t r a n s p o s o n p r o t e i n s f a m i l y p r o t e i n U O s 0 3 g 0 7 3 3 8 0 0 E n d o p l a s m i c o x i d o r e d u c t i n 1 p r e c u r s o r ( E C 1 8 4 ) U O s 0 2 g 0 8 0 3 3 0 0 E p s i n N t e r m i n a l d o m a i n c o n t a i n i n g p r o t e i n U O s 0 2 g 0 5 2 6 4 0 0 E R D 1 p r o t e i n c h l o r o p l a s t p r e c u r s o r U O s 0 5 g 0 4 7 3 5 0 0 E x o 7 0 e x o c y s t c o m p l e x s u b u n i t f a m i l y p r o t e i n U O s 0 6 g 0 2 5 5 9 0 0 E x o 7 0 e x o c y s t c o m p l e x s u b u n i t f a m i l y p r o t e i n U O s 1 0 g 0 5 4 2 4 0 0 E x p a n s i n / L o l p I f a m i l y p r o t e i n U O s 0 3 g 0 2 4 7 9 0 0 F 5 O 1 1 1 4 ( A C R 8 ) U O s 0 3 g 0 1 8 7 6 0 0 G R A M d o m a i n c o n t a i n i n g p r o t e i n U O s 0 4 g 0 6 8 8 3 0 0 H a e m p e r o x i d a s e p l a n t / f u n g a l / b a c t e r i a l f a m i l y p r o t e i n U O s 0 3 g 0 1 1 4 9 0 0 I n n e r m i t o c h o n d r i a l m e m b r a n e p r o t e i n U

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139 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 1 g 0 3 1 4 8 0 0 L a t e e m b r y o g e n e s i s a b u n d a n t p r o t e i n 3 f a m i l y p r o t e i n U O s 1 1 g 0 1 9 5 5 0 0 L i p a s e c l a s s 3 f a m i l y p r o t e i n U O s 0 3 g 0 7 3 8 6 0 0 L i p o x y g e n a s e L 2 ( E C 1 1 3 1 1 1 2 ) U O s 0 4 g 0 4 4 7 1 0 0 L i p o x y g e n a s e U O s 0 5 g 0 5 5 7 4 0 0 M e m b r a n e a t t a c k c o m p l e x c o m p o n e n t / p e r f o r i n / c o m p l e m e n t C 9 f a m i l y p r o t e i n U O s 0 5 g 0 3 9 2 7 0 0 M i t o c h o n d r i a l s u b s t r a t e c a r r i e r f a m i l y p r o t e i n U O s 0 8 g 0 5 2 0 0 0 0 M i t o c h o n d r i a l s u b s t r a t e c a r r i e r f a m i l y p r o t e i n U O s 0 9 g 0 5 2 4 3 0 0 M u l t i a n t i m i c r o b i a l e x t r u s i o n p r o t e i n M a t E f a m i l y p r o t e i n U O s 0 1 g 0 8 1 6 1 0 0 N A C d o m a i n c o n t a i n i n g p r o t e i n 2 ( A N A C 0 0 2 ) U O s 0 4 g 0 4 5 8 6 0 0 N o n c e l l a u t o n o m o u s p r o t e i n p a t h w a y 2 U O s 1 1 g 0 1 8 3 9 0 0 N u c e l l i n l i k e p r o t e i n U O s 0 2 g 0 7 9 1 5 0 0 N u c l e o t i d e s u g a r e p i m e r a s e l i k e p r o t e i n ( U D P D g l u c u r o n a t e 4 e p i m e r a s e ) ( E C 5 1 3 6 ) U O s 0 6 g 0 2 1 6 0 0 0 O x o p h y t o d i e n o i c a c i d r e d u c t a s e U O s 0 3 g 0 3 9 9 0 0 0 P e c t i n e s t e r a s e f a m i l y p r o t e i n U O s 1 0 g 0 5 3 7 8 0 0 P e p t i d a s e A 1 p e p s i n f a m i l y p r o t e i n U O s 0 2 g 0 1 3 6 0 0 0 P l a n t r e g u l a t o r R W P R K d o m a i n c o n t a i n i n g p r o t e i n U O s 0 3 g 0 2 0 3 7 0 0 P l a s m a m e m b r a n e C a 2 + A T P a s e U O s 0 7 g 0 2 7 4 7 0 0 H v B 1 2 D p r o t e i n ( B 1 2 D g 1 p r o t e i n ) U O s 0 9 g 0 5 3 6 7 0 0 N o d u l i n l i k e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 6 g 0 7 2 5 0 0 0 N t d i n U O s 0 2 g 0 7 5 7 1 0 0 P h i 1 p r o t e i n U O s 0 1 g 0 1 6 8 1 0 0 P r e f o l d i n f a m i l y p r o t e i n U O s 0 1 g 0 6 6 7 6 0 0 R a s r e l a t e d p r o t e i n R a b 1 1 B U O s 0 5 g 0 1 6 1 5 0 0 R e l A / S p o T d o m a i n c o n t a i n i n g p r o t e i n U O s 0 7 g 0 5 6 9 1 0 0 R e m o r i n C t e r m i n a l r e g i o n d o m a i n c o n t a i n i n g p r o t e i n U O s 0 7 g 0 6 9 5 4 0 0 S p e c t r i n r e p e a t c o n t a i n i n g p r o t e i n U O s 0 7 g 0 1 5 4 1 0 0 V i v i p a r o u s 1 4 U O s 0 7 g 0 4 1 2 1 0 0 G r a n u l e b o u n d s t a r c h s y n t h a s e I c h l o r o p l a s t p r e c u r s o r ( E C 2 4 1 2 1 ) ( G B S S I ) D O s 0 4 g 0 5 1 7 5 0 0 P h o s p h o e n o l p y r u v a t e c a r b o x y l a s e k i n a s e D O s 0 1 g 0 8 5 5 0 0 0 P h o s p h o l i p i d / g l y c e r o l a c y l t r a n s f e r a s e f a m i l y p r o t e i n D O s 1 0 g 0 5 5 8 7 0 0 2 O G F e ( I I ) o x y g e n a s e d o m a i n c o n t a i n i n g p r o t e i n D O s 0 9 g 0 3 4 4 5 0 0 O m e t h y l t r a n s f e r a s e Z R P 4 ( E C 2 1 1 ) ( O M T ) D

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140 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 7 g 0 1 8 1 1 0 0 C 4 d i c a r b o x y l a t e t r a n s p o r t e r / m a l i c a c i d t r a n s p o r t p r o t e i n f a m i l y p r o t e i n U O s 0 2 g 0 8 0 7 0 0 0 P h o s p h o e n o l p y r u v a t e c a r b o x y l a s e k i n a s e U O s 0 1 g 0 5 5 4 1 0 0 R N A d i r e c t e d D N A p o l y m e r a s e ( R e v e r s e t r a n s c r i p t a s e ) d o m a i n c o n t a i n i n g p r o t e i n U O s 0 3 g 0 8 0 3 5 0 0 2 O G F e ( I I ) o x y g e n a s e d o m a i n c o n t a i n i n g p r o t e i n U O s 1 0 g 0 5 5 9 5 0 0 2 O G F e ( I I ) o x y g e n a s e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 9 g 0 4 3 2 3 0 0 A A A A T P a s e c e n t r a l r e g i o n d o m a i n c o n t a i n i n g p r o t e i n U O s 0 6 g 0 6 7 6 7 0 0 H i g h p I a l p h a g l u c o s i d a s e U O s 0 8 g 0 1 9 0 1 0 0 O x a l a t e o x i d a s e l i k e p r o t e i n o r g e r m i n l i k e p r o t e i n ( G e r m i n l i k e 8 ) ( G e r m i n l i k e 1 2 ) U O s 0 5 g 0 4 9 5 6 0 0 P t y p e A T P a s e ( F r a g m e n t ) U O s 0 3 g 0 4 0 5 5 0 0 P D I l i k e p r o t e i n U O s 0 3 g 0 7 5 7 2 0 0 U D P g l u c u r o n o s y l / U D P g l u c o s y l t r a n s f e r a s e f a m i l y p r o t e i n D O s 0 1 g 0 5 9 1 0 0 0 C y t o s o l i c a l d e h y d e d e h y d r o g e n a s e D O s 0 7 g 0 6 5 9 4 0 0 H A D s u p e r f a m i l y h y d r o l a s e s u b f a m i l y I A v a r i a n t 1 p r o t e i n D O s 0 2 g 0 1 9 4 7 0 0 P l a n t l i p o x y g e n a s e f a m i l y p r o t e i n D O s 0 2 g 0 2 7 0 2 0 0 P e p t i d a s e S 8 a n d S 5 3 s u b t i l i s i n k e x i n s e d o l i s i n d o m a i n c o n t a i n i n g p r o t e i n U U U O s 1 0 g 0 3 9 5 4 0 0 G l u t a t h i o n e S t r a n s f e r a s e N t e r m i n a l d o m a i n c o n t a i n i n g p r o t e i n U U D O s 0 1 g 0 3 7 2 5 0 0 L e u c o a n t h o c y a n i d i n d i o x y g e n a s e 1 U U D O s 0 7 g 0 5 2 9 0 0 0 I s o c i t r a t e l y a s e ( E C 4 1 3 1 ) ( I s o c i t r a s e ) ( I s o c i t r a t a s e ) ( I C L ) U D O s 0 4 g 0 4 7 4 9 0 0 C y a n o g e n i c b e t a g l u c o s i d a s e p r e c u r s o r ( E C 3 2 1 2 1 ) ( L i n a m a r a s e ) ( F r a g m e n t ) U U O s 1 2 g 0 2 2 2 5 0 0 G l y c o s i d e h y d r o l a s e f a m i l y 1 9 p r o t e i n U U O s 0 8 g 0 4 1 4 7 0 0 G l y c o s y l t r a n s f e r a s e f a m i l y 2 0 d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 4 g 0 1 5 6 2 0 0 R i b u l o s e p h o s p h a t e b i n d i n g b a r r e l d o m a i n c o n t a i n i n g p r o t e i n U U O s 1 0 g 0 1 2 2 0 0 0 U D P g l u c u r o n o s y l / U D P g l u c o s y l t r a n s f e r a s e f a m i l y p r o t e i n U U O s 0 8 g 0 5 6 0 0 0 0 2 O G F e ( I I ) o x y g e n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 1 0 g 0 1 3 8 1 0 0 A l d e h y d e o x i d a s e ( E C 1 2 3 1 ) U U O s 1 1 g 0 6 1 3 9 0 0 B E D f i n g e r d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 1 g 0 7 3 8 6 0 0 E p s i n N t e r m i n a l d o m a i n c o n t a i n i n g p r o t e i n U U

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141 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 6 g 0 2 1 5 9 0 0 O x o p h y t o d i e n o i c a c i d r e d u c t a s e U U O s 0 1 g 0 6 1 3 5 0 0 P e p t i d a s e C 1 A p a p a i n f a m i l y p r o t e i n U U O s 0 2 g 0 2 7 1 6 0 0 P e p t i d a s e S 8 a n d S 5 3 s u b t i l i s i n k e x i n s e d o l i s i n d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 3 g 0 1 0 9 9 0 0 P e p t i d a s e t r y p s i n l i k e s e r i n e a n d c y s t e i n e p r o t e a s e s d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 8 g 0 2 4 0 0 0 0 S T F 1 ( F r a g m e n t ) U U O s 0 5 g 0 5 9 2 3 0 0 R m l C l i k e c u p i n f a m i l y p r o t e i n U U O s 0 4 g 0 5 7 8 6 0 0 F e r r i c r e d u c t a s e l i k e t r a n s m e m b r a n e c o m p o n e n t f a m i l y p r o t e i n U U O s 0 5 g 0 2 4 6 3 0 0 M a j o r p o l l e n a l l e r g e n L o l p I f a m i l y p r o t e i n U U O s 0 3 g 0 7 5 1 1 0 0 O l i g o p e p t i d e t r a n s p o r t e r O P T s u p e r f a m i l y p r o t e i n U U O s 1 1 g 0 6 4 1 5 0 0 M u l t i c o p p e r o x i d a s e t y p e 1 d o m a i n c o n t a i n i n g p r o t e i n D U U O s 0 4 g 0 5 8 1 1 0 0 I s o p e n i c i l l i n N s y n t h a s e f a m i l y p r o t e i n D U O s 1 0 g 0 1 1 3 0 0 0 N A D P H d e p e n d e n t c o d e i n o n e r e d u c t a s e ( E C 1 1 1 2 4 7 ) D D D O s 0 1 g 0 1 7 6 2 0 0 U D P g l u c u r o n o s y l / U D P g l u c o s y l t r a n s f e r a s e f a m i l y p r o t e i n D D O s 1 2 g 0 2 0 2 8 0 0 0 m e t h y l t r a n s f e r a s e ( E C 2 1 1 6 ) ( F r a g m e n t ) D D O s 1 2 g 0 2 3 0 1 0 0 A T P d e p e n d e n t C l p p r o t e a s e c h l o r o p l a s t p r e c u r s o r ( f r a g m e n t ) D D O s 1 2 g 0 1 4 3 8 0 0 M e i o t i c r e c o m b i n a t i o n p r o t e i n D M C 1 h o m o l o g D D O s 0 9 g 0 4 7 2 9 0 0 E x p a n s i n r e l a t e d p r o t e i n 2 p r e c u r s o r ( A t E X P R 2 ) ( A t h E x p G a m m a 1 1 ) D D O s 0 9 g 0 2 7 9 3 0 0 M i t o c h o n d r i a l i m p o r t i n n e r m e m b r a n e t r a n s l o c a s e s u b u n i t T i m 1 7 / 2 2 f a m i l y p r o t e i n D D O s 0 2 g 0 5 6 8 2 0 0 N o n p h o t o t r o p i c h y p o c o t y l 3 D D O s 1 0 g 0 1 1 8 0 0 0 O m e t h y l t r a n s f e r a s e Z R P 4 ( E C 2 1 1 ) ( O M T ) D D O s 1 1 g 0 4 3 9 6 0 0 N o d f a c t o r b i n d i n g l e c t i n n u c l e o t i d e p h o s p h o h y d r o l a s e D D O s 1 1 g 0 4 4 0 2 0 0 N o d f a c t o r b i n d i n g l e c t i n n u c l e o t i d e p h o s p h o h y d r o l a s e D D O s 0 7 g 0 6 6 4 3 0 0 G l u c o s e / r i b i t o l d e h y d r o g e n a s e f a m i l y p r o t e i n D D O s 0 5 g 0 3 9 9 3 0 0 G l y c o s i d e h y d r o l a s e f a m i l y 1 9 p r o t e i n D D O s 0 4 g 0 3 3 9 4 0 0 A l d o / k e t o r e d u c t a s e f a m i l y p r o t e i n D D O s 0 4 g 0 5 4 2 2 0 0 O l i g o p e p t i d e t r a n s p o r t e r O P T s u p e r f a m i l y p r o t e i n D D O s 0 4 g 0 5 5 6 4 0 0 C i s z e a t i n O g l u c o s y l t r a n s f e r a s e U U O s 0 4 g 0 5 5 6 5 0 0 C i s z e a t i n O g l u c o s y l t r a n s f e r a s e U U O s 0 1 g 0 6 6 7 9 0 0 G l u t a r e d o x i n d o m a i n c o n t a i n i n g p r o t e i n U U

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142 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 3 g 0 1 8 8 5 0 0 G l u t e l i n f a m i l y p r o t e i n U U O s 0 5 g 0 4 9 5 7 0 0 G l y c e r o l 3 p h o s p h a t e d e h y d r o g e n a s e l i k e p r o t e i n ( F r a g m e n t ) U U O s 0 4 g 0 5 0 6 8 0 0 G l y c o s y l t r a n s f e r a s e f a m i l y 2 9 p r o t e i n U U O s 0 2 g 0 2 0 5 5 0 0 N a r i n g e n i n c h a l c o n e s y n t h a s e f a m i l y p r o t e i n U U O s 1 0 g 0 4 9 7 7 0 0 P h y t o c h e l a t i n s y n t h e t a s e l i k e c o n s e r v e d r e g i o n f a m i l y p r o t e i n U U O s 0 8 g 0 1 3 7 8 0 0 P l a s t o c y a n i n l i k e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 8 g 0 4 8 2 6 0 0 P l a s t o c y a n i n l i k e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 3 g 0 4 3 2 1 0 0 P y r u v a t e p h o s p h a t e d i k i n a s e c h l o r o p l a s t p r e c u r s o r ( E C 2 7 9 1 ) U U O s 0 4 g 0 6 8 4 9 0 0 R i b o n u c l e a s e C A F 1 f a m i l y p r o t e i n U U O s 0 7 g 0 5 5 0 6 0 0 T r a n s f e r a s e f a m i l y p r o t e i n U U O s 1 0 g 0 3 8 0 1 0 0 T r a n s f e r a s e f a m i l y p r o t e i n U U O s 0 2 g 0 6 6 1 1 0 0 T r e h a l o s e 6 p h o s p h a t e p h o s p h a t a s e U U O s 0 4 g 0 4 9 7 0 0 0 ( + ) p u l e g o n e r e d u c t a s e D U U O s 0 8 g 0 4 4 8 0 0 0 4 c o u m a r a t e C o A l i g a s e 1 ( E C 6 2 1 1 2 ) ( 4 C L 1 ) ( F r a g m e n t ) U U O s 1 2 g 0 4 7 1 1 0 0 A A A A T P a s e c e n t r a l r e g i o n d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 2 g 0 7 3 9 1 0 0 A c t i n b i n d i n g F H 2 d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 8 g 0 4 7 3 9 0 0 A l p h a a m y l a s e t y p e B ( F r a g m e n t ) U U O s 0 1 g 0 5 9 7 6 0 0 A m i n o a c i d / p o l y a m i n e t r a n s p o r t e r I I f a m i l y p r o t e i n U U O s 0 4 g 0 6 8 8 1 0 0 A n i o n i c p e r o x i d a s e p r e c u r s o r U U O s 0 4 g 0 6 8 8 5 0 0 A n i o n i c p e r o x i d a s e p r e c u r s o r U U O s 0 3 g 0 2 9 0 3 0 0 F a t t y a c i d d e s a t u r a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 1 g 0 9 0 5 2 0 0 E x o 7 0 e x o c y s t c o m p l e x s u b u n i t f a m i l y p r o t e i n U U O s 0 1 g 0 3 2 6 3 0 0 H a e m p e r o x i d a s e p l a n t / f u n g a l / b a c t e r i a l f a m i l y p r o t e i n U U O s 0 6 g 0 5 2 1 5 0 0 H a e m p e r o x i d a s e p l a n t / f u n g a l / b a c t e r i a l f a m i l y p r o t e i n U U O s 0 6 g 0 6 5 2 2 0 0 H l y I I I r e l a t e d p r o t e i n s f a m i l y p r o t e i n U U O s 0 6 g 0 2 1 0 9 0 0 L i p a s e c l a s s 3 f a m i l y p r o t e i n U U O s 0 8 g 0 5 0 8 8 0 0 L i p o x y g e n a s e c h l o r o p l a s t p r e c u r s o r ( E C 1 1 3 1 1 1 2 ) U U O s 0 8 g 0 5 0 9 1 0 0 L i p o x y g e n a s e c h l o r o p l a s t p r e c u r s o r ( E C 1 1 3 1 1 1 2 ) U U O s 0 6 g 0 2 1 8 9 0 0 L M B R 1 l i k e c o n s e r v e d r e g i o n d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 3 g 0 2 2 6 2 0 0 N o n s y m b i o t i c h e m o g l o b i n 2 ( r H b 2 ) ( O R Y s a G L B 1 b ) U U O s 0 8 g 0 5 2 6 1 0 0 N u c l e o t i d e s u g a r e p i m e r a s e f a m i l y p r o t e i n U U

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143 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 4 g 0 5 9 7 8 0 0 O l i g o p e p t i d e t r a n s p o r t e r k i d n e y i s o f o r m ( P e p t i d e t r a n s p o r t e r 2 ) U U O s 0 8 g 0 1 8 9 9 0 0 O x a l a t e o x i d a s e l i k e p r o t e i n o r g e r m i n l i k e p r o t e i n ( G e r m i n l i k e 8 ) ( G e r m i n l i k e 1 2 ) U U O s 0 2 g 0 3 1 4 6 0 0 P e p t i d a s e A 1 p e p s i n f a m i l y p r o t e i n U U O s 0 2 g 0 6 9 3 4 0 0 P e p t i d a s e C 1 9 u b i q u i t i n c a r b o x y l t e r m i n a l h y d r o l a s e 2 f a m i l y p r o t e i n U U O s 0 1 g 0 8 9 2 5 0 0 P e c t i n a c e t y l e s t e r a s e f a m i l y p r o t e i n U U O s 1 0 g 0 5 2 1 9 0 0 R h o m b o i d l i k e p r o t e i n f a m i l y p r o t e i n U U O s 0 2 g 0 2 4 2 9 0 0 U D P g l u c u r o n o s y l / U D P g l u c o s y l t r a n s f e r a s e f a m i l y p r o t e i n U U O s 1 0 g 0 4 0 9 4 0 0 B U R P d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 2 g 0 6 3 0 3 0 0 2 O G F e ( I I ) o x y g e n a s e d o m a i n c o n t a i n i n g p r o t e i n D D O s 0 5 g 0 5 2 1 3 0 0 K i n e s i n 4 ( K i n e s i n l i k e p r o t e i n D ) D D O s 0 1 g 0 9 7 5 9 0 0 T o n o p l a s t m e m b r a n e i n t e g r a l p r o t e i n Z m T I P 1 2 D D O s 0 7 g 0 5 2 3 6 0 0 G l u c o s e 6 p h o s p h a t e / p h o s p h a t e t r a n s l o c a t o r p r e c u r s o r D U O s 0 1 g 0 2 4 1 4 0 0 G l u t a r e d o x i n d o m a i n c o n t a i n i n g p r o t e i n D U O s 0 4 g 0 4 1 2 3 0 0 G l y c o s i d e h y d r o l a s e f a m i l y 1 7 p r o t e i n D U O s 0 1 g 0 8 3 2 6 0 0 I s o p e n i c i l l i n N s y n t h a s e f a m i l y p r o t e i n D U O s 0 3 g 0 2 8 9 8 0 0 I s o p e n i c i l l i n N s y n t h a s e f a m i l y p r o t e i n D U O s 0 2 g 0 7 5 6 8 0 0 P h o s p h a t e i n d u c e d p r o t e i n 1 c o n s e r v e d r e g i o n f a m i l y p r o t e i n D U O s 0 9 g 0 5 3 8 0 0 0 R N a s e S l i k e p r o t e i n D U O s 0 6 g 0 2 4 2 0 0 0 S A M d e p e n d e n t c a r b o x y l m e t h y l t r a n s f e r a s e f a m i l y p r o t e i n D U O s 1 0 g 0 1 7 8 5 0 0 U D P g l u c u r o n o s y l / U D P g l u c o s y l t r a n s f e r a s e f a m i l y p r o t e i n D U O s 0 4 g 0 6 0 4 3 0 0 X y l o g l u c a n e n d o t r a n s g l u c o s y l a s e / h y d r o l a s e p r o t e i n 2 4 p r e c u r s o r ( E C 2 4 1 2 0 7 ) D U O s 0 4 g 0 4 4 9 2 0 0 X y l o g l u c a n f u c o s y l t r a n s f e r a s e f a m i l y p r o t e i n D U O s 0 8 g 0 3 9 1 7 0 0 2 O G F e ( I I ) o x y g e n a s e d o m a i n c o n t a i n i n g p r o t e i n D U O s 0 2 g 0 5 8 2 9 0 0 C o n o t o x i n f a m i l y p r o t e i n D U O s 0 7 g 0 5 6 3 4 0 0 C o t t o n f i b r e e x p r e s s e d f a m i l y p r o t e i n D U O s 0 1 g 0 2 4 3 0 0 0 E s t e r a s e / l i p a s e / t h i o e s t e r a s e d o m a i n c o n t a i n i n g p r o t e i n D U O s 0 1 g 0 7 1 6 8 0 0 E n d o n u c l e a s e / e x o n u c l e a s e / p h o s p h a t a s e f a m i l y p r o t e i n D U O s 0 6 g 0 2 1 6 3 0 0 O x o p h y t o d i e n o i c a c i d r e d u c t a s e ( 1 2 o x o p h y t o d i e n o i c a c i d r e d u c t a s e ) D U O s 0 6 g 0 2 1 6 2 0 0 O x o p h y t o d i e n o i c a c i d r e d u c t a s e D U

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144 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 1 g 0 8 4 8 7 0 0 R a s r e l a t e d p r o t e i n R a b 1 1 C D U O s 0 3 g 0 2 7 3 2 0 0 L a c c a s e ( E C 1 1 0 3 2 ) U D 1 T r e a t m e n t c o m p a r i s o n s : C S i = c o n t r o l v s s i l i c o n a m e n d e d S i S i P = s i l i c o n a m e n d e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d C P = c o n t r o l v s p a t h o g e n i n o c u l a t e d P S i P = p a t h o g e n i n o c u l a t e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d U = u p r e g u l a t e d D = d o w n r e g u l a t e d D i f f e r e n t i a l r e g u l a t i o n i s r e p o r t e d w i t h r e s p e c t t o t h e t r e a t m e n t o n t h e l e f t o f t h e c o m p a r i s o n

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145 Table A 6 E x pression profile of cytochrome P 450 encoding genes G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 1 g 0 6 2 7 8 0 0 C y t o c h r o m e P 4 5 0 m o n o o x y g e n a s e C Y P 7 2 A 5 ( F r a g m e n t ) D 1 O s 0 4 g 0 1 7 1 8 0 0 C y t o c h r o m e P 4 5 0 7 9 A 1 ( E C 1 1 4 1 3 4 1 ) ( T y r o s i n e N m o n o o x y g e n a s e ) D O s 0 1 g 0 5 4 4 2 0 0 C y t o c h r o m e P 4 5 0 f a m i l y p r o t e i n D O s 0 2 g 0 5 7 0 5 0 0 C y t o c h r o m e P 4 5 0 f a m i l y p r o t e i n D O s 0 4 g 0 1 7 4 1 0 0 E c l a s s P 4 5 0 g r o u p I f a m i l y p r o t e i n D O s 0 1 g 0 2 2 7 7 0 0 C y t o c h r o m e P 4 5 0 f a m i l y p r o t e i n U O s 1 0 g 0 1 4 4 7 0 0 C y t o c h r o m e P 4 5 0 f a m i l y p r o t e i n D D O s 1 0 g 0 5 1 5 9 0 0 E c l a s s P 4 5 0 g r o u p I f a m i l y p r o t e i n D D O s 0 9 g 0 4 4 7 3 0 0 C y t o c h r o m e P 4 5 0 f a m i l y p r o t e i n U U O s 0 2 g 0 7 0 3 6 0 0 C y t o c h r o m e P 4 5 0 9 0 C 1 ( E C 1 1 4 ) ( R O T U N D I F O L I A 3 ) D U U O s 1 1 g 0 1 5 1 4 0 0 C y t o c h r o m e P 4 5 0 f a m i l y p r o t e i n D U U O s 1 2 g 0 1 5 0 2 0 0 C y t o c h r o m e P 4 5 0 f a m i l y p r o t e i n D U U O s 0 5 g 0 2 1 1 1 0 0 C y t o c h r o m e P 4 5 0 5 1 ( E C 1 1 4 1 3 7 0 ) ( C Y P L I ) ( P 4 5 0 L I A 1 ) D U O s 0 9 g 0 4 5 7 1 0 0 C y t o c h r o m e P 4 5 0 f a m i l y p r o t e i n D U O s 1 1 g 0 4 8 3 0 0 0 C y t o c h r o m e P 4 5 0 f a m i l y p r o t e i n D U O s 1 2 g 0 5 8 2 7 0 0 C y t o c h r o m e P 4 5 0 f a m i l y p r o t e i n D U O s 0 6 g 0 2 9 4 6 0 0 C y t o c h r o m e P 4 5 0 f a m i l y p r o t e i n U U O s 0 8 g 0 5 0 7 1 0 0 E c l a s s P 4 5 0 g r o u p I f a m i l y p r o t e i n U U 1 T r e a t m e n t c o m p a r i s o n s : C S i = c o n t r o l v s s i l i c o n a m e n d e d S i S i P = s i l i c o n a m e n d e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d C P = c o n t r o l v s p a t h o g e n i n o c u l a t e d P S i P = p a t h o g e n i n o c u l a t e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d U = u p r e g u l a t e d D = d o w n r e g u l a t e d D i f f e r e n t i a l r e g u l a t i o n i s r e p o r t e d w i t h r e s p e c t t o t h e t r e a t m e n t o n t h e l e f t o f t h e c o m p a r i s o n

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146 Table A 7 E xpression profile of genes encoding proteins involved in protein protein interactions and/or protein turnover G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 2 g 0 7 1 5 0 0 0 C y s t e i n e p r o t e i n a s e G P I I ( E C 3 4 2 2 ) U 1 O s 0 5 g 0 3 9 3 1 0 0 L e u c i n e r i c h r e p e a t p l a n t s p e c i f i c c o n t a i n i n g p r o t e i n U O s 1 2 g 0 2 1 1 5 0 0 L e u c i n e r i c h r e p e a t p l a n t s p e c i f i c c o n t a i n i n g p r o t e i n U O s 1 0 g 0 4 6 9 0 0 0 L e u c i n e r i c h r e p e a t t y p i c a l s u b t y p e c o n t a i n i n g p r o t e i n U O s 0 2 g 0 5 4 0 7 0 0 U b o x d o m a i n c o n t a i n i n g p r o t e i n U O s 0 3 g 0 2 4 0 6 0 0 U b o x d o m a i n c o n t a i n i n g p r o t e i n U O s 0 6 g 0 2 4 8 5 0 0 U b o x d o m a i n c o n t a i n i n g p r o t e i n U O s 1 2 g 0 2 2 2 9 0 0 L e u c i n e r i c h r e p e a t t y p i c a l s u b t y p e c o n t a i n i n g p r o t e i n U U O s 0 9 g 0 5 7 3 1 0 0 U b i q u i t i n d o m a i n c o n t a i n i n g p r o t e i n D D D O s 0 3 g 0 6 6 7 1 0 0 B T B / P O Z d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 1 g 0 1 5 8 6 0 0 L e u c i n e r i c h r e p e a t t y p i c a l s u b t y p e c o n t a i n i n g p r o t e i n U U O s 0 3 g 0 1 9 0 3 0 0 L e u c i n e r i c h r e p e a t t y p i c a l s u b t y p e c o n t a i n i n g p r o t e i n U U O s 0 2 g 0 2 6 9 6 0 0 S u b t i l a s e U U O s 0 2 g 0 5 3 9 2 0 0 U b o x d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 4 g 0 6 8 6 0 0 0 U b o x d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 5 g 0 4 7 6 7 0 0 U b o x d o m a i n c o n t a i n i n g p r o t e i n U U 1 T r e a t m e n t c o m p a r i s o n s : C S i = c o n t r o l v s s i l i c o n a m e n d e d S i S i P = s i l i c o n a m e n d e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d C P = c o n t r o l v s p a t h o g e n i n o c u l a t e d P S i P = p a t h o g e n i n o c u l a t e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d U = u p r e g u l a t e d D = d o w n r e g u l a t e d D i f f e r e n t i a l r e g u l a t i o n i s r e p o r t e d w i t h r e s p e c t t o t h e t r e a t m e n t o n t h e l e f t o f t h e c o m p a r i s o n

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147 Table A 8 E xpression profile of genes involved in calcium signaling/binding G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 1 g 0 9 4 9 3 0 0 C a l c i u m b i n d i n g E F h a n d d o m a i n c o n t a i n i n g p r o t e i n U 1 O s 1 2 g 0 6 0 3 8 0 0 C a l m o d u l i n N t C a M 1 3 U O s 0 3 g 0 3 1 9 3 0 0 C a l m o d u l i n T a C a M 1 1 U O s 0 5 g 0 2 2 3 0 0 0 C a l m o d u l i n r e l a t e d p r o t e i n 2 t o u c h i n d u c e d U O s 0 6 g 0 6 8 3 4 0 0 E F h a n d C a 2 + b i n d i n g p r o t e i n C C D 1 U O s 0 9 g 0 4 7 1 8 0 0 E G F l i k e c a l c i u m b i n d i n g d o m a i n c o n t a i n i n g p r o t e i n U O s 0 1 g 0 7 4 3 1 0 0 I Q c a l m o d u l i n b i n d i n g r e g i o n d o m a i n c o n t a i n i n g p r o t e i n U O s 1 2 g 0 2 2 8 8 0 0 C a l m o d u l i n l i k e p r o t e i n U U O s 0 1 g 0 9 4 9 5 0 0 C a l m o d u l i n 2 / 3 / 5 D U U O s 0 7 g 0 5 6 8 6 0 0 C a l c i u m d e p e n d e n t p r o t e i n k i n a s e U U O s 0 2 g 0 8 0 7 2 0 0 E G F l i k e c a l c i u m b i n d i n g d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 9 g 0 5 6 2 6 0 0 E G F l i k e c a l c i u m b i n d i n g d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 1 g 0 1 3 5 7 0 0 F l a g e l l a r c a l c i u m b i n d i n g p r o t e i n ( c a l f l a g i n ) f a m i l y p r o t e i n U U O s 0 1 g 0 6 0 4 5 0 0 F l a g e l l a r c a l c i u m b i n d i n g p r o t e i n ( c a l f l a g i n ) f a m i l y p r o t e i n U U O s 0 5 g 0 5 7 7 5 0 0 F l a g e l l a r c a l c i u m b i n d i n g p r o t e i n ( c a l f l a g i n ) f a m i l y p r o t e i n U U O s 0 1 g 0 5 7 0 8 0 0 I Q c a l m o d u l i n b i n d i n g r e g i o n d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 5 g 0 5 4 1 1 0 0 I Q c a l m o d u l i n b i n d i n g r e g i o n d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 2 g 0 7 3 3 5 0 0 P a r v a l b u m i n f a m i l y p r o t e i n U U 1 T r e a t m e n t c o m p a r i s o n s : C S i = c o n t r o l v s s i l i c o n a m e n d e d S i S i P = s i l i c o n a m e n d e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d C P = c o n t r o l v s p a t h o g e n i n o c u l a t e d P S i P = p a t h o g e n i n o c u l a t e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d U = u p r e g u l a t e d D = d o w n r e g u l a t e d D i f f e r e n t i a l r e g u l a t i o n i s r e p o r t e d w i t h r e s p e c t t o t h e t r e a t m e n t o n t h e l e f t o f t h e c o m p a r i s o n

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148 T a b l e A 9 E xpression profile of kinase/phosphatase encoding genes G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 2 g 0 2 4 1 1 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n D 1 O s 0 1 g 0 6 5 6 2 0 0 P r o t e i n p h o s p h a t a s e 2 C f a m i l y p r o t e i n D O s 0 3 g 0 2 6 8 6 0 0 P r o t e i n p h o s p h a t a s e t y p e 2 C D O s 0 4 g 0 6 3 2 1 0 0 S l o c u s r e c e p t o r l i k e k i n a s e R L K 1 3 D O s 0 1 g 0 1 1 3 5 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 1 g 0 6 6 9 1 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 1 g 0 7 5 0 6 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 1 g 0 8 9 2 8 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 2 g 0 5 5 5 9 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 3 g 0 7 7 3 3 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 5 g 0 4 7 1 0 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 5 g 0 5 4 5 3 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U O s 1 0 g 0 4 6 8 5 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 6 g 0 5 4 1 6 0 0 P r o t e i n k i n a s e f a m i l y p r o t e i n U O s 0 7 g 0 1 8 6 2 0 0 P r o t e i n k i n a s e f a m i l y p r o t e i n U O s 0 9 g 0 4 0 8 9 0 0 P r o t e i n k i n a s e f a m i l y p r o t e i n U O s 1 1 g 0 2 0 8 7 0 0 P r o t e i n k i n a s e f a m i l y p r o t e i n U O s 1 1 g 0 6 6 7 6 0 0 P r o t e i n k i n a s e f a m i l y p r o t e i n U O s 0 4 g 0 3 4 0 1 0 0 P r o t e i n k i n a s e l i k e d o m a i n c o n t a i n i n g p r o t e i n U O s 1 0 g 0 1 3 4 9 0 0 P r o t e i n k i n a s e l i k e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 3 g 0 1 0 4 1 0 0 P r o t e i n p h o s p h a t a s e 2 C l i k e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 7 g 0 5 6 6 2 0 0 P r o t e i n p h o s p h a t a s e 2 C l i k e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 3 g 0 7 6 1 1 0 0 P r o t e i n p h o s p h a t a s e 2 C l i k e p r o t e i n U O s 0 8 g 0 3 7 4 6 0 0 R e c e p t o r k i n a s e l i k e p r o t e i n U O s 1 1 g 0 5 7 0 0 0 0 R e c e p t o r k i n a s e l i k e p r o t e i n U O s 1 1 g 0 2 0 8 8 0 0 R e c e p t o r l i k e p r o t e i n k i n a s e U O s 0 7 g 0 6 8 0 9 0 0 S e r i n e / t h r e o n i n e p r o t e i n k i n a s e A t P K 1 9 ( E C 2 7 1 3 7 ) U O s 1 2 g 0 2 2 4 0 0 0 D i a c y l g l y c e r o l k i n a s e 2 ( A t 5 g 6 3 7 7 0 ) ( E C 2 7 1 1 0 7 ) U O s 0 2 g 0 7 8 7 8 0 0 D i a c y l g l y c e r o l k i n a s e c a t a l y t i c r e g i o n d o m a i n c o n t a i n i n g p r o t e i n U

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149 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 9 g 0 5 3 3 6 0 0 P r o b a b l e s e r i n e / t h r e o n i n e p r o t e i n k i n a s e N A K ( E C 2 7 1 3 7 ) U O s 0 1 g 0 8 4 6 3 0 0 P r o t e i n p h o s p h a t a s e 2 C ( P P 2 C ) ( E C 3 1 3 1 6 ) D O s 0 2 g 0 8 2 2 9 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 9 g 0 3 5 0 9 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 7 g 0 5 3 8 3 0 0 S e r i n e / t h r e o n i n e k i n a s e r e c e p t o r l i k e p r o t e i n U O s 0 4 g 0 6 3 4 7 0 0 D i a c y l g l y c e r o l k i n a s e U O s 0 1 g 0 6 5 5 5 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 7 g 0 5 4 1 9 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U U O s 1 1 g 0 6 9 1 5 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 1 1 g 0 6 9 5 8 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 1 g 0 1 1 4 1 0 0 P r o t e i n k i n a s e f a m i l y p r o t e i n U U O s 1 1 g 0 6 2 5 2 0 0 P r o t e i n k i n a s e f a m i l y p r o t e i n U U O s 0 1 g 0 1 2 4 4 0 0 P r o t e i n a s e i n h i b i t o r I 1 2 B o w m a n B i r k f a m i l y p r o t e i n D D U O s 1 0 g 0 1 4 2 6 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n D D O s 0 1 g 0 1 1 7 6 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n D D O s 0 1 g 0 6 9 0 8 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n D D O s 1 1 g 0 6 2 5 9 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n D D O s 1 1 g 0 6 9 4 1 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n D D O s 0 3 g 0 7 6 2 0 0 0 C a s e i n k i n a s e I I a l p h a s u b u n i t D D O s 0 1 g 0 6 9 9 1 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n D U O s 0 1 g 0 6 9 9 4 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n D U O s 0 4 g 0 5 6 3 9 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n D U O s 0 2 g 0 1 2 6 4 0 0 P r o t e i n k i n a s e C P K 1 U U O s 0 1 g 0 1 2 7 7 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 1 g 0 6 9 9 5 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 1 g 0 6 9 9 6 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 2 g 0 1 6 5 1 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 2 g 0 6 8 1 7 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 4 g 0 3 7 1 7 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 4 g 0 6 1 9 4 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 5 g 0 1 6 5 9 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 5 g 0 1 6 6 3 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 5 g 0 4 8 6 1 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U

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150 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 7 g 0 5 3 7 5 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 8 g 0 2 0 3 1 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 9 g 0 4 0 0 5 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 9 g 0 5 6 1 6 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 1 1 g 0 6 6 6 2 0 0 P r o t e i n k i n a s e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 4 g 0 4 1 9 9 0 0 P r o t e i n k i n a s e f a m i l y p r o t e i n U U O s 0 3 g 0 8 2 1 3 0 0 P r o t e i n p h o s p h a t a s e 2 C l i k e d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 7 g 0 5 5 0 9 0 0 R e c e p t o r l i k e p r o t e i n k i n a s e 6 U U O s 0 2 g 0 8 0 7 9 0 0 S e r i n e t h r e o n i n e k i n a s e U U O s 0 1 g 0 9 3 4 1 0 0 C 2 d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 5 g 0 4 9 3 1 0 0 K I d o m a i n i n t e r a c t i n g k i n a s e 1 U U O s 0 3 g 0 2 8 5 8 0 0 M A P k i n a s e 1 ( M A P k i n a s e M A P K 5 a ) U U O s 0 1 g 0 8 4 1 7 0 0 R P P 1 7 1 U U 1 T r e a t m e n t c o m p a r i s o n s : C S i = c o n t r o l v s s i l i c o n a m e n d e d S i S i P = s i l i c o n a m e n d e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d C P = c o n t r o l v s p a t h o g e n i n o c u l a t e d P S i P = p a t h o g e n i n o c u l a t e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d U = u p r e g u l a t e d D = d o w n r e g u l a t e d D i f f e r e n t i a l r e g u l a t i o n i s r e p o r t e d w i t h r e s p e c t t o t h e t r e a t m e n t o n t h e l e f t o f t h e c o m p a r i s o n

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151 Table A 10 E xpression profile of genes with unknown function G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 3 g 0 7 3 6 9 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U 1 O s 0 2 g 0 1 1 0 5 0 0 H y p o t h e t i c a l p r o t e i n U O s 1 1 g 0 2 3 5 4 0 0 H y p o t h e t i c a l p r o t e i n U O s 1 1 g 0 5 9 4 8 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 5 3 8 f a m i l y p r o t e i n U O s 0 5 g 0 5 5 1 0 0 0 P r o t e i n o f u n k n o w n f u n c t i o n H H E d o m a i n c o n t a i n i n g p r o t e i n U O s 0 1 g 0 7 9 3 3 0 0 ( N o H i t ) D O s 0 9 g 0 4 7 2 7 0 0 ( N o H i t ) D O s 0 2 g 0 2 5 9 9 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D O s 0 5 g 0 4 4 8 7 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D O s 0 9 g 0 3 0 4 8 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D O s 0 2 g 0 2 1 2 3 0 0 H y p o t h e t i c a l p r o t e i n D O s 0 6 g 0 4 9 3 1 0 0 H y p o t h e t i c a l p r o t e i n D O s 1 0 g 0 3 4 8 9 0 0 H y p o t h e t i c a l p r o t e i n D O s 1 0 g 0 3 6 0 6 0 0 H y p o t h e t i c a l p r o t e i n D O s 1 0 g 0 3 7 2 8 0 0 H y p o t h e t i c a l p r o t e i n D O s 1 1 g 0 2 1 1 8 0 0 H y p o t h e t i c a l p r o t e i n D O s 1 2 g 0 2 2 1 4 0 0 H y p o t h e t i c a l p r o t e i n D O s 1 2 g 0 2 2 9 1 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c h a r a c t e r i z e d t r a n s c r i p t D O s 1 1 g 0 5 4 0 6 0 0 P l a n t p r o t e i n o f u n k n o w n f u n c t i o n f a m i l y p r o t e i n D O s 0 9 g 0 3 9 6 9 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 1 2 5 f a m i l y p r o t e i n D O s 0 5 g 0 4 0 9 5 0 0 M t N 2 1 p r o t e i n D O s 0 1 g 0 2 1 2 0 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 7 g 0 1 4 2 3 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 7 g 0 1 4 2 5 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 7 g 0 5 6 5 8 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 7 g 0 5 9 9 9 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 8 g 0 4 7 8 0 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 1 2 g 0 5 8 0 6 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 3 g 0 1 0 7 7 0 0 E L 2 p r o t e i n U

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152 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 3 g 0 3 0 4 1 0 0 H y p o t h e t i c a l p r o t e i n U O s 0 5 g 0 3 5 5 9 0 0 H y p o t h e t i c a l p r o t e i n U O s 1 2 g 0 4 5 3 5 0 0 H y p o t h e t i c a l p r o t e i n U O s 0 3 g 0 2 4 5 2 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 1 2 1 0 f a m i l y p r o t e i n U O s 0 5 g 0 4 5 4 2 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 3 1 5 d o m a i n c o n t a i n i n g p r o t e i n U O s 0 8 g 0 3 3 5 6 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 5 6 8 d o m a i n c o n t a i n i n g p r o t e i n U O s 0 3 g 0 7 4 6 9 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D O s 0 5 g 0 1 4 2 9 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D O s 0 5 g 0 4 2 1 6 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D O s 0 4 g 0 5 5 8 7 0 0 H y p o t h e t i c a l p r o t e i n D O s 0 3 g 0 2 3 3 0 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 6 0 7 f a m i l y p r o t e i n D O s 0 5 g 0 5 8 8 9 0 0 B C S 1 p r o t e i n l i k e p r o t e i n D O s 0 5 g 0 2 1 4 3 0 0 M t N 3 a n d s a l i v a r e l a t e d t r a n s m e m b r a n e p r o t e i n f a m i l y p r o t e i n D O s 0 3 g 0 4 3 1 6 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U U O s 0 7 g 0 1 4 2 1 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U U O s 1 1 g 0 2 6 2 6 0 0 H y p o t h e t i c a l p r o t e i n U U U O s 0 1 g 0 6 4 7 2 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c l a s s i f i a b l e t r a n s c r i p t U U U O s 0 8 g 0 4 6 6 6 0 0 ( N o H i t ) U U O s 0 9 g 0 1 3 0 3 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 1 2 g 0 2 3 6 1 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 3 g 0 7 2 5 2 0 0 H y p o t h e t i c a l p r o t e i n U U O s 1 0 g 0 1 2 8 0 0 0 H y p o t h e t i c a l p r o t e i n U U O s 1 2 g 0 2 8 2 0 0 0 H y p o t h e t i c a l p r o t e i n U U O s 0 1 g 0 4 9 4 3 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t p u t a t i v e n p R N A U U O s 0 3 g 0 4 3 9 7 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 1 2 3 0 f a m i l y p r o t e i n U U O s 0 1 g 0 1 1 5 1 0 0 ( N o H i t ) U U O s 0 1 g 0 8 2 9 3 0 0 ( N o H i t ) U U

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153 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 3 g 0 2 2 8 9 0 0 ( N o H i t ) U U O s 0 4 g 0 1 3 6 6 0 0 ( N o H i t ) U U O s 0 4 g 0 1 9 7 5 0 0 ( N o H i t ) U U O s 1 1 g 0 6 9 5 0 0 0 ( N o H i t ) U U O s 1 2 g 0 4 6 8 1 0 0 ( N o H i t ) U U O s 0 1 g 0 3 6 3 5 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 1 g 0 5 6 7 2 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 2 g 0 3 1 0 2 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 3 g 0 6 2 9 8 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 6 g 0 1 8 9 6 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 8 g 0 3 3 8 0 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 9 g 0 2 6 9 9 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 1 1 g 0 6 9 2 0 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 3 g 0 2 4 7 3 0 0 H y p o t h e t i c a l p r o t e i n U U O s 0 5 g 0 2 2 7 1 0 0 H y p o t h e t i c a l p r o t e i n U U O s 0 8 g 0 2 4 0 2 0 0 H y p o t h e t i c a l p r o t e i n U U O s 0 8 g 0 4 4 1 8 0 0 H y p o t h e t i c a l p r o t e i n U U O s 1 1 g 0 2 3 5 7 0 0 H y p o t h e t i c a l p r o t e i n U U O s 1 1 g 0 6 8 7 2 0 0 H y p o t h e t i c a l p r o t e i n U U O s 1 1 g 0 4 2 2 0 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c h a r a c t e r i z e d t r a n s c r i p t U U O s 1 1 g 0 2 3 5 3 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c l a s s i f i a b l e t r a n s c r i p t U U O s 0 8 g 0 3 5 1 2 0 0 P l a n t p r o t e i n o f u n k n o w n f u n c t i o n f a m i l y p r o t e i n U U O s 0 3 g 0 2 6 9 9 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 6 0 4 f a m i l y p r o t e i n U U O s 0 4 g 0 3 1 1 3 0 0 V i r a l c o a t a n d c a p s i d p r o t e i n f a m i l y p r o t e i n U U O s 0 1 g 0 1 5 5 8 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U D O s 0 1 g 0 3 6 0 1 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U D O s 0 7 g 0 6 8 8 7 0 0 E g g s h e l l p r o t e i n f a m i l y p r o t e i n U D O s 0 8 g 0 3 7 1 2 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D U D U O s 0 8 g 0 4 1 3 5 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 1 2 6 2 f a m i l y p r o t e i n D U D U O s 1 0 g 0 3 6 0 7 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D D D

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154 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 1 g 0 1 8 9 7 0 0 H y p o t h e t i c a l p r o t e i n D D D O s 0 1 g 0 8 4 4 0 0 0 ( N o H i t ) D D O s 0 4 g 0 4 2 6 7 0 0 ( N o H i t ) D D O s 0 6 g 0 5 7 8 7 0 0 ( N o H i t ) D D O s 0 8 g 0 3 0 1 0 0 0 ( N o H i t ) D D O s 1 2 g 0 5 4 3 8 0 0 ( N o H i t ) D D O s 0 8 g 0 4 1 2 5 0 0 B r a i n p r o t e i n 4 4 l i k e p r o t e i n D D O s 0 1 g 0 1 8 9 8 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D D O s 0 1 g 0 6 0 4 1 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D D O s 0 1 g 0 8 2 0 8 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D D O s 0 1 g 0 9 3 1 1 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D D O s 0 1 g 0 9 6 1 6 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D D O s 0 8 g 0 4 1 1 5 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D D O s 0 8 g 0 4 2 1 4 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D D O s 1 0 g 0 1 3 7 3 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D D O s 1 0 g 0 3 7 1 6 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D D O s 1 2 g 0 1 6 9 3 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D D O s 0 1 g 0 6 8 7 7 0 0 E u k a r y o t i c p r o t e i n o f u n k n o w n f u n c t i o n D U F 2 9 2 d o m a i n c o n t a i n i n g p r o t e i n D D O s 0 1 g 0 3 2 0 7 0 0 H y p o t h e t i c a l p r o t e i n D D O s 0 1 g 0 5 9 8 9 0 0 H y p o t h e t i c a l p r o t e i n D D O s 0 2 g 0 1 7 3 3 0 0 H y p o t h e t i c a l p r o t e i n D D O s 0 8 g 0 1 8 4 8 0 0 H y p o t h e t i c a l p r o t e i n D D O s 0 8 g 0 2 3 1 1 0 0 H y p o t h e t i c a l p r o t e i n D D O s 0 9 g 0 4 9 6 4 0 0 H y p o t h e t i c a l p r o t e i n D D O s 1 0 g 0 1 1 1 8 0 0 H y p o t h e t i c a l p r o t e i n D D O s 1 1 g 0 6 2 6 7 0 0 H y p o t h e t i c a l p r o t e i n D D O s 1 1 g 0 6 9 4 0 0 0 H y p o t h e t i c a l p r o t e i n D D O s 1 2 g 0 2 1 8 3 0 0 H y p o t h e t i c a l p r o t e i n D D O s 1 2 g 0 2 2 1 6 0 0 H y p o t h e t i c a l p r o t e i n D D O s 1 2 g 0 2 2 2 3 0 0 H y p o t h e t i c a l p r o t e i n D D O s 1 2 g 0 2 2 8 5 0 0 H y p o t h e t i c a l p r o t e i n D D O s 0 1 g 0 9 6 2 0 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c l a s s i f i a b l e t r a n s c r i p t D D O s 1 2 g 0 2 1 7 8 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c l a s s i f i a b l e D D

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155 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P t r a n s c r i p t O s 1 2 g 0 2 1 8 1 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c l a s s i f i a b l e t r a n s c r i p t D D O s 0 8 g 0 4 1 2 7 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 1 2 6 2 f a m i l y p r o t e i n D D O s 0 2 g 0 5 1 3 8 0 0 O v a r i a n t u m o u r o t u b a i n d o m a i n c o n t a i n i n g p r o t e i n D D O s 0 1 g 0 2 5 1 4 0 0 H y p o t h e t i c a l p r o t e i n U D O s 0 6 g 0 1 8 8 4 0 0 H y p o t h e t i c a l p r o t e i n U D O s 1 0 g 0 1 5 0 3 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 1 2 1 0 f a m i l y p r o t e i n U D O s 0 4 g 0 2 8 0 5 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 1 g 0 3 9 2 6 0 0 H y p o t h e t i c a l p r o t e i n U U O s 0 5 g 0 3 9 4 0 0 0 ( N o H i t ) D U U O s 0 9 g 0 2 5 9 4 0 0 ( N o H i t ) D U U O s 0 1 g 0 9 5 2 9 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D U U O s 0 2 g 0 7 3 3 9 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D U U O s 0 5 g 0 5 1 6 7 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D U U O s 0 3 g 0 1 8 3 5 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 5 8 1 f a m i l y p r o t e i n D U U O s 0 1 g 0 1 8 0 2 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 6 3 5 f a m i l y p r o t e i n D U U O s 0 2 g 0 7 4 8 3 0 0 V M P 3 p r o t e i n D U U O s 0 1 g 0 8 2 1 3 0 0 ( N o H i t ) D U O s 0 2 g 0 6 7 6 8 0 0 ( N o H i t ) D U O s 0 5 g 0 1 6 2 8 0 0 ( N o H i t ) D U O s 0 5 g 0 5 4 5 7 0 0 ( N o H i t ) D U O s 0 7 g 0 1 2 5 5 0 0 ( N o H i t ) D U O s 0 7 g 0 1 2 6 7 0 0 ( N o H i t ) D U O s 0 1 g 0 1 3 0 9 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D U O s 0 1 g 0 3 0 6 4 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D U O s 0 2 g 0 5 2 7 2 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D U O s 0 2 g 0 7 8 7 7 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D U O s 0 3 g 0 1 2 6 9 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D U O s 0 3 g 0 7 4 0 2 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D U

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156 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 7 g 0 6 6 1 4 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D U O s 0 9 g 0 3 8 0 6 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D U O s 1 0 g 0 5 8 0 9 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D U O s 0 2 g 0 5 9 7 3 0 0 H y p o t h e t i c a l p r o t e i n D U O s 0 3 g 0 1 8 7 4 0 0 H y p o t h e t i c a l p r o t e i n D U O s 0 3 g 0 3 4 2 1 0 0 H y p o t h e t i c a l p r o t e i n D U O s 0 5 g 0 4 2 0 0 0 0 H y p o t h e t i c a l p r o t e i n D U O s 0 5 g 0 1 3 0 3 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t p u t a t i v e n p R N A D U O s 0 3 g 0 2 7 7 7 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 2 6 d o m a i n c o n t a i n i n g p r o t e i n D U O s 1 2 g 0 5 4 8 7 0 0 C I 2 C D U O s 0 7 g 0 6 8 6 6 0 0 V Q d o m a i n c o n t a i n i n g p r o t e i n D U O s 1 2 g 0 2 4 2 1 0 0 E g g s h e l l p r o t e i n f a m i l y p r o t e i n D D O s 0 1 g 0 1 3 6 7 0 0 ( N o H i t ) U O s 0 1 g 0 5 1 2 9 0 0 ( N o H i t ) U O s 0 1 g 0 5 5 4 8 0 0 ( N o H i t ) U O s 0 1 g 0 7 0 5 0 0 0 ( N o H i t ) U O s 0 1 g 0 7 2 5 0 0 0 ( N o H i t ) U O s 0 1 g 0 9 7 0 1 0 0 ( N o H i t ) U O s 0 2 g 0 2 0 6 2 0 0 ( N o H i t ) U O s 0 2 g 0 5 6 0 2 0 0 ( N o H i t ) U O s 0 2 g 0 5 6 1 0 0 0 ( N o H i t ) U O s 0 2 g 0 5 6 1 4 0 0 ( N o H i t ) U O s 0 2 g 0 5 6 1 8 0 0 ( N o H i t ) U O s 0 2 g 0 8 3 4 6 0 0 ( N o H i t ) U O s 0 3 g 0 1 5 5 0 0 0 ( N o H i t ) U O s 0 3 g 0 2 8 5 2 0 0 ( N o H i t ) U O s 0 3 g 0 3 4 2 4 0 0 ( N o H i t ) U O s 0 3 g 0 6 5 5 1 0 0 ( N o H i t ) U O s 0 4 g 0 2 5 8 7 0 0 ( N o H i t ) U O s 0 5 g 0 3 6 9 1 0 0 ( N o H i t ) U O s 0 5 g 0 4 6 8 9 0 0 ( N o H i t ) U O s 0 5 g 0 4 6 8 9 0 0 ( N o H i t ) U O s 0 6 g 0 2 0 8 2 0 0 ( N o H i t ) U

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157 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 6 g 0 5 7 2 6 0 0 ( N o H i t ) U O s 0 7 g 0 5 6 0 1 0 0 ( N o H i t ) U O s 0 7 g 0 5 8 7 3 0 0 ( N o H i t ) U O s 0 8 g 0 1 8 1 8 0 0 ( N o H i t ) U O s 1 1 g 0 2 4 2 2 0 0 ( N o H i t ) U O s 1 1 g 0 5 5 7 5 0 0 ( N o H i t ) U O s 1 2 g 0 5 0 5 8 0 0 ( N o H i t ) U O s 0 8 g 0 4 7 8 7 0 0 B r a i n m i t o c h o n d r i a l c a r r i e r p r o t e i n 1 ( B M C P 1 ) ( M i t o c h o n d r i a l u n c o u p l i n g p r o t e i n 5 ) U O s 0 1 g 0 1 9 4 0 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 1 g 0 5 5 1 0 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 1 g 0 7 9 9 0 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 1 g 0 8 3 3 4 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 1 g 0 8 5 0 1 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 1 g 0 8 6 4 2 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 1 g 0 8 8 8 8 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 1 g 0 9 3 4 4 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 2 g 0 1 6 2 6 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 2 g 0 3 2 4 7 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 2 g 0 5 6 6 3 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 3 g 0 1 4 8 4 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 4 g 0 6 4 0 9 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 5 g 0 5 4 6 3 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 6 g 0 7 1 3 1 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 7 g 0 1 9 4 8 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 7 g 0 5 8 0 2 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 7 g 0 5 8 9 6 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 7 g 0 6 5 9 3 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 9 g 0 4 1 6 6 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 1 0 g 0 3 5 8 1 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 1 0 g 0 5 3 6 4 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 1 1 g 0 2 0 7 3 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 1 1 g 0 4 7 1 2 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 2 g 0 8 1 4 0 0 0 E u k a r y o t i c p r o t e i n o f u n k n o w n f u n c t i o n D U F 8 6 2 f a m i l y p r o t e i n U

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158 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 1 g 0 1 2 1 5 0 0 H y p o t h e t i c a l p r o t e i n U O s 0 1 g 0 8 1 4 4 0 0 H y p o t h e t i c a l p r o t e i n U O s 0 1 g 0 8 3 4 9 0 0 H y p o t h e t i c a l p r o t e i n U O s 0 3 g 0 3 0 5 2 0 0 H y p o t h e t i c a l p r o t e i n U O s 0 3 g 0 3 3 4 2 0 0 H y p o t h e t i c a l p r o t e i n U O s 0 4 g 0 4 1 4 5 0 0 H y p o t h e t i c a l p r o t e i n U O s 0 4 g 0 6 2 1 9 0 0 H y p o t h e t i c a l p r o t e i n U O s 1 2 g 0 1 1 3 6 0 0 H y p o t h e t i c a l p r o t e i n U O s 0 2 g 0 7 9 2 1 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t p u t a t i v e n p R N A U O s 0 4 g 0 6 3 4 6 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c h a r a c t e r i z e d t r a n s c r i p t U O s 0 4 g 0 6 3 9 0 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c h a r a c t e r i z e d t r a n s c r i p t U O s 0 5 g 0 5 6 3 9 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c h a r a c t e r i z e d t r a n s c r i p t U O s 0 8 g 0 4 5 2 9 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c h a r a c t e r i z e d t r a n s c r i p t U O s 0 2 g 0 2 0 9 3 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c l a s s i f i a b l e t r a n s c r i p t U O s 0 3 g 0 7 1 6 9 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c l a s s i f i a b l e t r a n s c r i p t U O s 0 3 g 0 7 4 0 9 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c l a s s i f i a b l e t r a n s c r i p t U O s 0 9 g 0 4 2 5 5 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c l a s s i f i a b l e t r a n s c r i p t U O s 0 3 g 0 7 7 3 0 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 1 0 0 5 f a m i l y p r o t e i n U O s 0 3 g 0 7 3 9 7 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 1 3 3 4 f a m i l y p r o t e i n U O s 0 4 g 0 6 5 9 3 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 2 6 d o m a i n c o n t a i n i n g p r o t e i n U O s 0 7 g 0 5 3 0 6 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 2 9 9 f a m i l y p r o t e i n U O s 0 1 g 0 9 5 6 2 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 5 6 3 f a m i l y U

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159 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P p r o t e i n O s 1 1 g 0 5 7 5 5 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 5 6 3 f a m i l y p r o t e i n U O s 0 1 g 0 7 2 7 5 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 5 8 4 f a m i l y p r o t e i n U O s 0 1 g 0 7 9 8 8 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 5 9 4 f a m i l y p r o t e i n U O s 1 1 g 0 1 3 6 3 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 6 d o m a i n c o n t a i n i n g p r o t e i n U O s 1 2 g 0 5 1 8 2 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 6 d o m a i n c o n t a i n i n g p r o t e i n U O s 0 1 g 0 8 1 7 0 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 6 0 7 f a m i l y p r o t e i n U O s 0 2 g 0 6 5 4 6 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 6 3 0 d o m a i n c o n t a i n i n g p r o t e i n U O s 1 2 g 0 1 6 4 6 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 7 9 3 f a m i l y p r o t e i n U O s 0 1 g 0 9 4 8 5 0 0 A R M r e p e a t f o l d d o m a i n c o n t a i n i n g p r o t e i n U O s 0 3 g 0 2 9 7 6 0 0 B e t v I a l l e r g e n f a m i l y p r o t e i n U O s 1 0 g 0 4 9 9 4 0 0 C B S d o m a i n c o n t a i n i n g p r o t e i n U O s 0 1 g 0 6 9 5 8 0 0 M u l t i d r u g r e s i s t a n c e p r o t e i n 1 h o m o l o g U O s 0 4 g 0 4 6 1 6 0 0 P G P S / D 1 2 U O s 1 0 g 0 3 4 3 1 0 0 t s n a r e d o m a i n c o n t a i n i n g p r o t e i n U O s 0 1 g 0 7 9 6 0 0 0 ( N o H i t ) U U O s 0 2 g 0 5 8 4 7 0 0 ( N o H i t ) U U O s 0 2 g 0 8 0 7 8 0 0 ( N o H i t ) U U O s 0 7 g 0 2 0 8 3 0 0 ( N o H i t ) U U O s 0 8 g 0 1 3 7 9 0 0 ( N o H i t ) U U O s 0 8 g 0 1 7 3 3 0 0 ( N o H i t ) U U O s 0 8 g 0 5 1 6 4 0 0 ( N o H i t ) U U O s 1 2 g 0 1 1 1 8 0 0 ( N o H i t ) U U O s 0 1 g 0 1 3 4 7 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 1 g 0 7 1 4 6 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 2 g 0 6 0 1 0 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 2 g 0 7 3 6 9 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U

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160 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 3 g 0 1 7 0 1 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 3 g 0 7 3 4 5 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 4 g 0 5 8 6 5 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 5 g 0 5 4 6 4 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 5 g 0 5 5 2 8 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 6 g 0 1 3 3 3 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 6 g 0 1 3 3 5 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 6 g 0 2 0 1 2 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 6 g 0 2 0 3 6 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 7 g 0 6 8 0 6 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 8 g 0 4 0 2 5 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 8 g 0 4 4 8 1 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 1 0 g 0 5 6 3 8 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U U O s 0 3 g 0 7 1 0 0 0 0 E u k a r y o t i c p r o t e i n o f u n k n o w n f u n c t i o n D U F 2 9 2 d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 1 g 0 1 8 6 9 0 0 H y p o t h e t i c a l p r o t e i n U U O s 0 1 g 0 7 6 8 1 0 0 H y p o t h e t i c a l p r o t e i n U U O s 0 1 g 0 8 3 3 6 0 0 H y p o t h e t i c a l p r o t e i n U U O s 0 1 g 0 9 0 5 3 0 0 H y p o t h e t i c a l p r o t e i n U U O s 0 2 g 0 5 9 7 2 0 0 H y p o t h e t i c a l p r o t e i n U U O s 0 3 g 0 2 5 5 9 0 0 H y p o t h e t i c a l p r o t e i n U U O s 0 3 g 0 7 2 3 7 0 0 H y p o t h e t i c a l p r o t e i n U U O s 0 5 g 0 1 8 1 7 0 0 H y p o t h e t i c a l p r o t e i n U U O s 0 6 g 0 3 1 8 8 0 0 H y p o t h e t i c a l p r o t e i n U U O s 0 7 g 0 5 6 1 8 0 0 H y p o t h e t i c a l p r o t e i n U U O s 1 1 g 0 5 7 2 2 0 0 H y p o t h e t i c a l p r o t e i n U U O s 1 2 g 0 4 9 9 2 0 0 H y p o t h e t i c a l p r o t e i n U U O s 1 2 g 0 5 5 6 2 0 0 H y p o t h e t i c a l p r o t e i n U U O s 1 2 g 0 5 9 2 9 0 0 H y p o t h e t i c a l p r o t e i n U U O s 0 9 g 0 2 4 6 3 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c h a r a c t e r i z e d t r a n s c r i p t U U O s 0 1 g 0 1 3 7 8 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c l a s s i f i a b l e t r a n s c r i p t U U O s 0 5 g 0 1 3 1 0 0 0 P l a n t p r o t e i n o f u n k n o w n f u n c t i o n f a m i l y p r o t e i n U U

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161 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 3 g 0 1 8 7 8 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 2 5 0 d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 3 g 0 2 7 7 6 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 2 6 d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 4 g 0 3 1 6 2 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 2 6 d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 4 g 0 3 2 2 1 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 2 6 d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 1 g 0 4 9 8 3 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 5 6 3 f a m i l y p r o t e i n U U O s 0 3 g 0 8 1 6 8 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 5 6 7 f a m i l y p r o t e i n U U O s 0 1 g 0 8 4 5 1 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 6 6 8 f a m i l y p r o t e i n U U O s 0 1 g 0 3 8 9 2 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 6 7 9 f a m i l y p r o t e i n U U O s 0 1 g 0 3 8 9 7 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 6 7 9 f a m i l y p r o t e i n U U O s 0 1 g 0 9 7 5 0 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 9 6 6 f a m i l y p r o t e i n U U O s 0 2 g 0 3 2 7 5 0 0 A r a b i d o p s i s p r o t e i n o f u n k n o w n f u n c t i o n D U F 2 6 6 f a m i l y p r o t e i n U U O s 1 0 g 0 5 5 5 1 0 0 D N A c h r o m o s o m e 4 E S S A I C O N T I G f r a g m e n t N O 6 ( G l u c o s y l t r a n s f e r a s e l i k e p r o t e i n ) U U O s 0 1 g 0 5 7 5 2 0 0 R b ( F r a g m e n t ) U U O s 0 2 g 0 4 3 7 2 0 0 S N A P 3 4 U U O s 0 2 g 0 2 5 1 9 0 0 V Q d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 3 g 0 6 7 6 4 0 0 V Q d o m a i n c o n t a i n i n g p r o t e i n U U O s 0 5 g 0 4 6 3 3 0 0 ( N o H i t ) D O s 0 1 g 0 7 9 8 2 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D O s 0 2 g 0 1 9 1 8 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D O s 0 2 g 0 1 9 3 1 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D O s 0 2 g 0 4 8 5 0 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D O s 0 2 g 0 6 8 4 4 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D

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162 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 3 g 0 7 4 6 7 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D O s 0 6 g 0 1 4 7 1 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D O s 0 6 g 0 5 2 3 3 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D O s 0 8 g 0 4 2 0 7 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D O s 0 2 g 0 1 6 0 5 0 0 H y p o t h e t i c a l p r o t e i n D O s 1 0 g 0 3 6 4 9 0 0 H y p o t h e t i c a l p r o t e i n D O s 1 2 g 0 6 0 3 9 0 0 N o n p r o t e i n c o d i n g t r a n s c r i p t u n c h a r a c t e r i z e d t r a n s c r i p t D O s 0 1 g 0 5 9 2 5 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 1 0 7 0 f a m i l y p r o t e i n D O s 1 0 g 0 1 5 0 6 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 1 2 1 0 f a m i l y p r o t e i n D O s 1 0 g 0 1 5 0 7 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 1 2 1 0 f a m i l y p r o t e i n D O s 0 6 g 0 7 1 4 8 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 5 8 1 f a m i l y p r o t e i n D O s 0 1 g 0 7 7 8 6 0 0 ( N o H i t ) U O s 0 6 g 0 1 7 4 0 0 0 ( N o H i t ) U O s 0 8 g 0 2 1 9 8 0 0 ( N o H i t ) U O s 1 1 g 0 1 5 6 6 0 0 ( N o H i t ) U O s 0 1 g 0 7 3 1 1 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 2 g 0 1 3 4 2 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 6 g 0 1 3 3 4 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 9 g 0 4 9 8 2 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 1 1 g 0 1 1 5 6 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 1 2 g 0 1 8 6 6 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n U O s 0 3 g 0 1 1 4 1 0 0 H y p o t h e t i c a l p r o t e i n U O s 1 1 g 0 2 9 1 5 0 0 H y p o t h e t i c a l p r o t e i n U O s 1 1 g 0 4 8 2 2 0 0 H y p o t h e t i c a l p r o t e i n U O s 1 2 g 0 1 4 1 0 0 0 H y p o t h e t i c a l p r o t e i n U O s 0 1 g 0 9 7 2 0 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 1 1 1 7 d o m a i n c o n t a i n i n g p r o t e i n U O s 0 1 g 0 9 7 3 1 0 0 ( N o H i t ) D O s 0 3 g 0 1 6 8 3 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D O s 0 4 g 0 2 8 2 4 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D

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163 G e n e D e s c r i p t i o n C S i P S i P C P S i S i P O s 0 6 g 0 2 7 8 0 0 0 C o n s e r v e d h y p o t h e t i c a l p r o t e i n D O s 0 1 g 0 5 5 0 8 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 2 3 9 d o m a i n c o n t a i n i n g p r o t e i n D O s 0 6 g 0 2 7 7 9 0 0 P r o t e i n o f u n k n o w n f u n c t i o n D U F 2 3 9 d o m a i n c o n t a i n i n g p r o t e i n D 1 T r e a t m e n t c o m p a r i s o n s : C S i = c o n t r o l v s s i l i c o n a m e n d e d S i S i P = s i l i c o n a m e n d e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d C P = c o n t r o l v s p a t h o g e n i n o c u l a t e d P S i P = p a t h o g e n i n o c u l a t e d v s s i l i c o n a m e n d e d a n d p a t h o g e n i n o c u l a t e d U = u p r e g u l a t e d D = d o w n r e g u l a t e d D i f f e r e n t i a l r e g u l a t i o n i s r e p o r t e d w i t h r e s p e c t t o t h e t r e a t m e n t o n t h e l e f t o f t h e c o m p a r i s o n

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164 R EFERENCES Adatia, M.H. and Besford, R.T. 1986. The effect of silicon on cucumber plants grown in recirculating nutrient solution. Ann. Bot. 58:343 351. Aharoni, Y., Fallik, E., Copel, A., Gil, M., Grinberg, S., and Klein, J. D. 1997 Sodium bicarb onate reduces postharvest decay development on melons. Postharv Biol and Technol 10: 201 206. Altschul, S. F., Gish, W., Miller, W., Myers, E. W., and Lipman, D. J. 1990 Basic local alignment search tool. J. Mol Biol 215:403 10 Alvarez, J., Datnoff, L.E ., and Snyder, G. H. 2004. The Economics of Silicon Applications on Rice and Sugarcane in Florida, Gainesville, Fla., University of Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, EDIS. Arnon, D. and Stout, P. 1939 The e ssentiality of certain elements in minute quantity for plants with special refer ence to copper. Plant Physiol. 14: 371 375. Belanger, R. R., Benhamou, N., and Menzies, J. 2003 Cytological evidence of an active role of silicon in wheat resistance to powdery mildew ( Blumeria graminis f. sp. tritici ). Phytopa thology 93:402 412 Berger, R., Filho, A.B., and Amorim, L. 1997. Lesion expansion as an epidemic component. Phytopathology 87:1005 1013. Bi, Y., Tian, S., Guo, Y., Ge, Y., and Qin, G. 2006. Sodium silicat e reduces postharvest decay on Hami melons: induced resistance and fungistatic effects. Plant Dis. 90.279 283. Bolstad, B., Irizarry, R., Astrand, M., and Speed, T. 2003 A comparison of normalization methods for high density oligonucleotide array data bas ed on variance and bias. Bioinformatics 19: 185 1 93. Bowen, P., Menzies, J., Ehret, D., Samuels, L., and Glass, A.D. 1992 Soluble silicon sprays inhibit powdery mildew development on grape Leaves. J Am Soc Hort Sci. 117:906 912 Brady, N.C., and Weil, R.R. 2002 The Nature and Properties of Soils, Upper Saddle River, N.J, Prentice Hall. Brecht, M., Stiles, C., and Datnoff, L. 2007b. Evaluation of pathogenicity of Bipolaris and Curvularia spp. on dwarf and ultradwarf bermudagrasses in Florida. Plant Heal th Progress. Online at: http://www.plantmanagementnetwork.org/pub/php/research/2007/dwarf/ American Phytopathological Society, St. Paul, MN. Brecht, M.O., Datnoff, L.E., Kucha rek, T.A., and Nagata, R.T. 2007a. The influence of silicon on the compounds of resistance to gray leaf spot in St. Augustinegrass. J. Plant Nutr. 30:1005 1021.

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165 Brecht, M.O., Datnoff, L.E., Kucharek, T.A., and Nagata, R.T. 2004 Influence of silicon and ch lorothalonil on the suppression of gray leaf spot and increase plant growth in St. Augustinegrass. Plant Dis. 88:338 344 Britez, R.M., Watanabe,T., Jansen,S., Reissmann, C.B., and Osaki, M. 2002 The relationship between aluminium and silicon accumulation in leaves of Faramea marginata (Rubiaceae ). New Phytol 156:437 444 Carver, T. Zeyen, R., and Ahlstrand, G. 1987 The relationship between insoluble silicon and success or failure of attempted primary penetration by powdery mildew ( Erysiphe graminis ) ge rmlings on barley. Physiol Mol Plant Pathol 31: 133 148. Chemical Rubber Company. 2005 CRC Handbook of Chemistry and Physics, Boca Raton, FL, CRC Press. Chrif, M., Menzies, J., Benhamou, N., and Blanger, R. 1992. Studies of silicon distribution in wou nded and Pythium ultimum infected cu cumber plants. Physiol. Mol. Plant Pathol. 41: 411 425. Comhaire, M. 1966. The role of sil ica for plants. AGRI Digest 7: 9 19 Dann, E. and Muir, S. 2002. Peas grown in media with elevated plant available silicon levels ha ve high er activities of chitinase and 1,3 glucanase are less susceptible to a fungal leaf spot pathogen and accumulate more foliar silicon. Australas. Plant Pathol. 31:9 13. Daroub, S.H. and Snyder, G.H. 2007 The chemi stry of plant nutrients in soil. In : L.E. Datnoff, W.H. Elmer, and D.H. Huber (Eds.) Mineral Nutrition and Plant Disease St. Paul, Minn, The American Phytopatholo gical Society pp. 1 7. Datnoff, L. and Nagata, R. 1999 Influence of silicon on gray leaf spot development i n St. Augustinegrass (Abstract). Phytopathology 89: S19. Datnoff, L. and Rutherford, B. 2003 Accumulation of silicon by bermudagrass to enhance disease suppression and of leaf spot and melting out. Turfgrass and Environ Res Online, 2: 1 6. Online at: http://usgatero.msu.edu/ (Last accessed October 14, 2008). Datnoff, L., Ma, J., and Mitani, N. 2008. Influence of insoluble and soluble silicon on leaf blast development in rice. p. 17. In: Silicon in Agriculture Conference South Africa, 4th International Conference 26 31 October, Wild Coast Sun, Port Edward, KwaZulu Natal, South Africa. Datnoff, L., Raid, R., Snyder, G., and Jones, D. 1991 Effect of calcium silicate on blast and brown spot intensities and yields of rice. Plant Dis 75: 729 7 32. D atnoff, L.E. and Rodrigues, F.A. 2005 The role of silicon in suppressing rice diseases. APSnet Feature. Online at: http://www.apsnet.org/online/feature/silicon/default.asp ( Last a ccessed September 14, 2008).

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166 Datnoff, L. E. Deren, C.W., and Snyder, G.H. 1997 Silicon fertilization for disease management of rice in Florida. Crop Prot 16:525 531 Datnoff, L.E., Nell, T. A., Leonard, R., and Rutherford, B.A. 2006 Effect of silicon on powdery mildew development on miniature potted rose (Abstract). Phy topathology 96: S28. Datnoff, L.E., Rodrigues, F.A., and Seebold, K.W. 2007. Silicon and plant disease. In: L.E. Datnoff, W.H. Elmer, and D.H. Huber (Eds.) Mineral nutrition and plant diseas e. St. Paul, MN, APS Press, pp.233 246. Datnoff, L. E., S nyder, G.H., and Deren, C.W. 1992. Influence of silicon fertilizer grades on blast and brown spot development and on rice yields. Plant Dis. 76: 1011 1013. Datnoff, L. E., Snyder G.H., and Korndrfer, G.H. 2001 Silicon in Agriculture, New York, Elsevier. Deepak, S., Manjunath, G., Manjula, S., Niranjan Raj, S., Geetha, N., and Shetty, H. 2008. Involvement of silicon in pearl millet resistance to downy mildew disease and its interplay with cell wall pro line/hydroxyproline rich glycoproteins. Australas Plant Pathol. 37: 498 504. Dhin gra, O.D. and Sinclair, J.B. 1995 Basic plant pathology methods, Boca Raton, CRC Press, Inc. Dietrich, D., Hinke, S., Baumann, W., Fehlhaber, R., Bucker, E., Rhle, G., Wien haus, O., and Marx, G. 2003 Silica accumulation in Triticum aestivum L. and Dactylis glomerata L. Anal Bioanal Chem 376:399 404. Drechsler, C. 1923. Some graminicolous species of Helmint hosporium; I. J. Agric. Res. 24 :641 740. Elliott, C. and Snyder, G .H. 1991 Autoclave induced digestion for the colorimetric determination of silicon in rice straw. J Agri Food Chem 39: 1118 1119. Epstein, E. 1994 The anomaly of silicon in plant biology. Proc Natl. Acad. Sci USA, 91:11 7 Epstein, E. 1999 Silicon. Ann Rev Plant Physiol Mol Biol. 50: 641 664. Epstein, E. 2001 Silico n in plants: Facts vs. concepts. I n : L.E. Datnoff, G.H. Snyder, G.H. Korndrfer (Eds.) Silicon in Agriculture Studies in Plant Science, No. 8. Amsterdam, Elsevier Science B.V., pp. 1 1 5. Fauteux, F., Chain, F., Belzile, F., Menzi es, J. G., and Blanger, R. R. 2006 The protective role of silicon in the Arabidopsis powdery mildew pathosystem. Proc Natl. Acad. Sci USA, 103: 17554 1755 9.

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167 Frantz, J. M. Pitchay, D.D., Locke, J.C., Horst, L. E., and Krause, C.R. 2005 Silicon is deposited in leaves of New Guinea impatiens. Plant Health Progr. Online at: http://www.apsnet.org/pmnabstracts/php/4588.htm Last accessed on November 30, 2 008. Ghanmi, D., McNally, D. J., Benhamou, N. Menzies, J. G., and B langer, R.R. 2004 Powdery mildew of Arabidopsis thaliana : a pathosystem for exploring the role of silicon in plant microbe interactions. Physiol Mol Plant Pathol 64: 189 199. Gillman, J. H., Zlesak, D.C., and Smith, J.A. 2003. Applications of potassium silicate decrease black spot infection in Rosa hybrida Meipelta' (Fu schia Me idiland). HortScience 38: 1073 1031. Hayasaka, T., Fujii, H., and Ishiguro, K. 2008. The role of silicon in preventing appressorial penetration by the rice blast fungus. Phytopathology 98:1038 1044. Heath, M.C. 1979 Partial characterization of the electro n opaque deposits formed in the non host plant, French bean, after cowpea rust infection. Physiol Plant Pathol 15:141 144, IN5 IN6, 145 148 Heath M.C., Howard, R.J., Valent, B., and Chumley, F.G. 1992. Ultrastructural interactions of one strain of Magn aporthe grisea with goosegrass and weeping lovegrass. Can. J Bot 70: 779 787. Hodson, M.J., White, P.J., Mead, A., and Broadley, M.R. 2005 Phylogenetic variation in the silicon composition of plants. Ann Bot 96:1027 1046 Honda, Y. and Aragaki, M. 197 8a. Photosporogenesis in Exserohilum rostratum : temperature effects on sporulation and sporemorphology. Mycologia 70:343 354. Honda, Y. and Aragaki, M. 1978b. Stability of hilum protuberance in Exserohilum species Mycologia 70: 547 555. Horsfall, J. and Ba rratt, R. 1945 An improved grading system for measuring plant d isease (Abstr.). Phytopathology 35: 655. Ihaka, R. and Gentleman, R. 1996. R: A language for data analysis and graphics. Journal of Compoutatio nal and Graphical Statistics, 5:299 314 Ishiguro, K. 2001. Review of research in Japan on the roles of silicon in conferring resistance against rice blast. In: L.E. Datnoff, G.H. Snyder, G.H. Korndrfer (Eds.) Silicon in Agriculture Studies in Plant Science, No 8. Amsterdam, Elsevier Science B.V. pp.277 291. Jenny, H. 1941 Factors of Soil Formation; a System of Quantitative Pedology, New York, McGraw Hill.

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168 Jin, W., Riley, R., Wolfinger, R., White, K., Passa dor Gurgel, G., and Gibson, G. 2001. The contributions of sex, genotype and age to transcriptional variance in Drosophila melanogaster Nat. Genet. 29: 389 95. Jin, W., Riley, R., Wolfinger, R., White, K., Passa dor Gurgel, G., and Gibson, G. 2001 The contributions of sex, genotype and age to transcriptional variance in Drosophila melanogaster Nat. Gen et. 29: 389 95. Kaiser, C., van der Merwe, R., B ekker, T., and Labuschagne, N. 2005. In vitro inhibition of mycelial growth of several phytopathogenic fungi, including Phytophthora cinnamomi by soluble silicon. South African Avocado Gro wers' Association Yea rbook 28: 70 74. Kamenidou, S., Cavins, T., and Marek, S. 2008. Silicon supplements affect horticultural traits of greenhouse produced sunflowers. HortScience 43:236 239. Kanto, T., Maekawa, K., and Aino, M. 2007. Suppression of conidial germination and app ressorial formation by silicate treatment in powdery mildew of strawberry. J. Gen. Plant Pathol. 73:1 7. Kema, G., Yu, D., Rijkenberg, F., Shaw, M., and Baayen, R. 1996. Histology of the pathogenesis of Septoria tritici in wheat. Phytopathology 86:777 786. K im, S.G., Kim, K.W., Park, E.W., and Choi, D. 2002 Silicon induced cell wall fortification of rice leaves: a possible cellular mechanism of enhanced host resistance to blast. P hytopathology 92: 1095 1103. Kinrade, S.D., Del Nin, J.W., Schach, A.S., Sloan T.A., Wilson, K.L., and Knight, C.T.G. 1999. Stable five and six coordinated silicate anions in aqueous solution. Science 285:1542 1545. Kinrade, S.D., Schach, A.S., Hamilton, R.J., and Knight, C.T.G. 2001. NMR evidence of pentaoxo organosilicon complex es in dilute neutral aqueous silicate solutions. Chem. Comm. 17:1564 1565. Knight, T. and Kinrade, S.D. 2001. A primer on the aqueous chemistry of silicon. In: L.E. Datnoff, G.H. Snyder, G.H. Korndrfer (Eds.) Silicon in Agriculture Studies in Plant Scien ce, No 8. Amsterdam, Elsevier Science B.V. pp.57 84. Kucharek, T. 1973. Stalk rot of corn caused by Helminthosporium rostratum Phytopathology 63:1336 1338. Kunoh, H. and Ishizaki, H. 1975. Silicon levels near penetration sites of fungi on wheat, barley, c ucumber and morning glory leaves. Physiol. Plant Pathol. 5:283 287. Larkin, M., Blackshields, G., Brown, N., Chenna, R., McGettigan, P., McWilliam, H., Valentin, F., Wallace, I., Wilm, A., Lopez, R., Thompson, J., Gibson, T., and Higgins, D. 2007. Clustal W and Clustal X version 2.0. Bioinformatics (Oxford, England), 23:2947 2948.

PAGE 169

169 Leonard, K.J. 1976. Synonymy of Exserohilum halodes with E. rostratum and induction of the ascigerous state, Setosphaeria rostrata Mycologia. 68:402 411. Leonard, K.J. and Suggs E.G. 1974. Setosphaeria prolata the ascigerous state of Exserohilum prolatum Mycologia. 66:281 297. Liang, Y., Hua, H., Zhu, Y., Zhang, J., Cheng, C., and Volker, R. 2006. Importance of plant species and external silicon concentration to active silicon uptake and transport. New Phytol. 172:63 72. Liang, Y., Su n, W., Si, J., and Rmheld, V. 2005 Effects of foliar and root applied silicon on the enhancement of induced resistance to powdery mildew in Cucumis sativus Plant Pathol 54: 678 685. Locke, J., Omer, M., Frantz, J., Widrig, A., Zellner, W ., Leisner, S., and Krause, C. 2008 Potential use of silicon to alleviate disease stress in floriculture crop production. Phytopathology 98: S93. Locke, J. C., Om er, M., Widrig, A., and Krause, C. 2006 Delay of e xpression of powdery mildew on zinna grown hydroponically in Hoagland' s solution fortified wi th silicon. Phytopathology 96: S70. Lott, T.J., Kuykendall, R.J., and Reiss, E. 1993 Nucleotide sequence analysis of the 5.8S rDNA and adjacent ITS2 region of Cand ida albicans and related species. Yeast 9:1199 1206. Luttrell, E. 1958. The perfect stage of Helmintosporium turcicum Phytopathology 48:281 287. Luu, D. and Maurel, C. 2005. Aquaporins in a challenging environment: molecular gears for adjusting plant wate r status. Plant Cell Environ. 28:85 96. Ma, J. F., Mitani, N., Nagao, S., Konishi, S., Tamai, K., Iwashita, T., and Yano, M. 2004. Characterization of the silicon uptake system and molecular mapping of the silicon transporter gene in rice. Plant Physiol. 1 36:3284 3289. Ma, J. F., Nishimura, K., and Takahasi, E. 1989. Effect of silicon on the growth of rice plant at different growth stages. Jpn. J. Soil Sci. Plant Nutr. 35:347 356. Ma, J.F. and Yamaji, N. 2006 Silicon uptake and accumulat ion in higher plant s. Trends Plant Sci 11: 392 397. Ma, J.F., Goto, S., Tamai, K., and Ichii, M. 2001a. Role of root hairs and lateral roots in silicon uptake by rice. Plant Physiol. 127:1773 1780. Ma, J.F., Miyake, Y., and Takahashi, E. 2001b. Silicon as a beneficial elemen t for crop plants. In: L.E. Datnoff, G.H. Snyder, G.H. Korndrfer (Eds.) Silicon in Agriculture. Studies in Plant Science, No 8. Amsterdam, Elsevier Science B.V. pp.17 39.

PAGE 170

170 Ma, J.F., Tamai, K., Yamaji, N., Mitani, N., Konishi, S., Katsuhara, M., Ishiguro, M ., Murata, Y., and Yano, M. 2002. A silicon transporter in rice. Nature 440:688 691. Ma, J.F., Yamaji, N., Mitani, N., Tamai, K., Konishi, S., Fujiwara, T., Katsuhara, M., and Yano, M. 2007. An efflux transporter of silicon in rice. Nature 448:209 12. M cAv oy, R.J. and Bible, B.B. 1996 Silica sprays reduce the incidence and severity of bract necr osis in poinsettia. HortScience 31:1146 1149 Menzies, J.G., Ehret, D.L., Glass, A.D.M., Helmer, T., Koch, C., and Seywerd, F. 1991. Effects of soluble silicon on t he parasitic fitness of Sphaerotheca fuliginea on Cucumis sativus Phytopathology 81:84 88. Mitani, N. and Ma, J.F. 2005. Uptake system of silicon in different plant species. J. Exp. Bot. 56:1255 1261. Miyake, Y. and Takahashi, E. 1983 Effect of silicon o n the growth of cucumber plant in soil culture. S oil Sci. Plant Nutr. 29: 463 471. Nakai, K. and Horton, P. 1999 PSORT: a program for detecting sorting signals in proteins and predicting their subc ellular localization. Trends Biochem. Science 24: 34 6. Nana yakkara, U., Uddin, W., and Datnoff, L.E. 2008a. Application of silicon sources increases silicon accumulation in perennial ryegrass turf on two soil types. Plant and Soil 303 : 83 94. Nanayakkara, U., Uddin, W., and Datnoff, L. E. 2008b. Effects of soil typ e, source of silicon, and rate of silicon source on development of gray leaf spot of perennial ryegr ass turf. Plant Dis. 92:870 877 Neumann, D. and De Figueiredo, C. 2002. A novel mechanism of silicon uptake. Protoplasma 220:59 67. Park, J., Kim, K.W., Pa rk, T., Park, E.W., and Kim, Y. 2006 Solid state NMR spectroscopy of silicon treated rice with enhanced host resistance against blast. Anal Sci Intl J Jp n Soc Anal Chem 22:645 8 Pratt, R. G. and Bri nk, G.E. 2007 Forage bermudagrass cultivar respo nses to inoculations with Exserohilum rostratum and Bipolaris spicifera and relationships to field persistence. Crop Sci. 47 : 239 244. Pratt, R. 2006. Johnsongrass, yellow foxtail, and broadleaf signalgrass as new hosts for six species of Bipolaris Curvula ria and Exserohilum pathogenic to bermudagrass. Plant Dis. 90:528. Raleigh, G.J. 1939 Evidence for the essentiality of silicon for growth o f the beet plant. Plant Physiol. 14: 823 828.

PAGE 171

171 Raven, J.A. 2001. Silicon transport at the cell and tissue level. In: L.E. Datnoff, G.H. Snyder, G.H. Korndrfer (Eds.) Silicon in Agriculture Studies in Plant Science, No 8. Amsterdam, Elsevier, pp.41 55. Rodrigues, F., Benhamou, N., Datnoff, L., Jones, J., and Blanger, R. 2003a. Ultrastructural and cytochemical aspects of silicon mediated rice bl ast resistance. Phytopathology 93: 535 546. Rodrigues, F., Jurick, W., Datnoff, L., Jones, J., and Rollins, J. 2005 Silicon influences cytological and molecular events in compatibe and incompatible rice Magnaporthe grisea intera ctions. Physiol Mol Plant Pathol. 66: 144 159. Rodrigues, F.A., Datnoff, L.E., Korndrfer, G.H., Seebold, K., and Rush, M. 2001. Effect of silicon and host resistance on sheath blight development in rice. Plant Dis. 85:827 832. Rodrigues, F.A., McNally, D J. Datnoff, L.E., Jones, J. B., Labbe, C., Benhamou, N., Menzi es, J.G., and Blanger, R.R. 2004 Silicon enhances the accumulation of diterpenoid phytoalexins in rice: A potential mechanism for b last resistance. Phytopathology 94:177 183. Rodrigues, F.A., Vale, F.X., Datnoff, L.E., Prabhu, A.S., and Korndrfer, G. H. 2003b. Effect of rice growth stages and silicon on sheath bli ght development. Phytopathology 93: 256 261. Saikia, D., Goswami, T., and Chaliha, B. 1992. Paper from Thysanolaena maxima Bioresou rce Technol. 40:245 248. Samuels, A., Glass, A., Ehret, D., and Menzies, J. 1991. Mobility and deposition of silicon in cucumb er plants. Plant Cell Environ. 14:485 492. Sangster, A. G. and Hodson, M. J. 1986. Silica in higher plants. In: Silicon Biochemist ry Ciba Foundation Symposium. John Wiley & Sons, pp.90 107. Sangster, A.G., Hodson, M.J., and Tubb, H.J. 2001 Sili con deposition in higher plants. In: L.E. Datnoff, G.H. Snyder, G.H. Korndrfer (Eds.) Silicon in Agriculture Studies in Plant Science No 8 Amsterdam, Elsevier Science B.V. pp. 85 113. Savant, N., Snyder, G., and Datnoff, L. 1997. Silicon management and sustainable rice production. Adv. Agron. 68:151 199. Seebold, K., Datnoff, L., Correa Victoria, F., Kucharek, T., and Snyder, G. 2000. Effec t of silicon rate and host resistance on blast, scald, and yield of upland rice. Pant Dis. 84:871 876. Seebold, K., Datnoff, L. E., Co rrea Victoria, F., Kucharek, T.A., and Snyder, G.H. 2004. Effects of silicon and fungicides on the control of leaf and neck blast in upland rice. Plant Dis 88:253 258.

PAGE 172

172 Seebold K., Kucharek, T., Datnoff, L. E., Correa V ictoria, F., and Marchetti, M. 2 001. The influence of silicon on components of resistance to blast in susceptible, partially resistant, and resistant cu ltivars of rice. Phytopathology 91:63 39 Shi, Q., Bao, Z., Zhu, Z., He, Y., Qian, Q., and Yu, J. 2005. Silicon mediated alleviation of Mn toxicity in Cucumis sativus in relation to activities of superoxide dismutase and ascorbate peroxidase. Phytochemistry 66:155 1 1559. Sivanesan, A. 1987. Graminicolous Species of Bipolaris, Curvularia, Drechslera, Exserohilum and Their Teleomorphs Wallingford, Oxon, C.A.B International. Sommer, M., Kaczorek, D. Kuzyakov, Y., and Breuer, J. 2006. Silicon pools and fluxes in soil s and landscapes a review. J Plant Nutr. Soil Sci 169: 310 329. Storey, J. 2002. A direct approach to false discovery rates. J. R. Statist. Soc. B. 64:479 498. Storey, J. and Tibshirani, R. 2003. Statistical significance for genomewide studies. Proc. Natl Acad. Sci. USA 100:9440 9445. Storey, J., Taylor, J., and Siegmund, D. 2004. Strong control, conservative point estimation and simultaneous conservative consistency of false discovery rates: A unified approach. J. R. Statist. Soc. B. 66:187 205. Takahash i, E. and Miyake, Y. 1977. Silica and plant growth. In: Proceedings of the International Seminar on Soil Environment and Fertility Management in Intensive Agriculture. Kyoto, Society of the Science of Soil and Manure, Showado Press pp. 603 611. Takahashi, E and Miyake, Y. 1982. The effects of silicon on the growth of cucumber plant -comparative studies on the silicon nutrition In A. Scaife (Ed.) Plant Nutrition 1982: Proceedings of the ninth International Plant Nutrition Colloquium, Warwick University, Eng land Slough, UK, Co mmonwealth Agricultural Bureaux pp. 664 669. Volk, R.J., Kahn, R.P., and Weintraub, R.L. 1958. Silicon content of the rice plant as a factor influencing its resistance to infection by the blast fungus Piricularia oryzae Phytopathology 4 8: 121 178. Voogt, W. and Sonneveld, C. 2001. Silicon in horticultural crops grown in soilless culture. In: L.E. Datnoff, G.H. Snyder, G.H. Korndrfer (Eds.). Silicon in Agriculture. Studies in Plant Science, No. 8. A msterdam, Elsevier Science B.V. pp. 115 1 31. Watanabe, S., Shimoi, E., Ohkama, N., Hayashi, H., Yoneyama, T., Yazaki, J., Fujii, F., Shinbo, K., Yamamoto, K., Sakata, K., Sasaki, T., Kishimoto, N., Kikuchi, S., and Fujiwara, T. 2004. Identification of several rice genes regulated by Si nutrition. Soil Sci. Plant Nutr. 50:1273 1276. Whitehead, M. and Calvert, O. 1959. Helminthosporium rostratum inciting ear rot of corn and leaf spot of thirteen grass hosts. Phytopathology 49:817 820.

PAGE 173

173 Williams, D.E. and Vlamis, J. 1957. The effect of silicon on yiel d and manganese 54 uptake and distribution in the leaves of barley plants grown in culture solutions. Plant Ph ysiol. 32:2404 409. Yamaji, N., Mitani, N., and Ma, J.F. 2008. A transporter regulating silicon distribution in rice shoots. Plant Cell 20:1381 13 89. Young, G., Lefebvre, C., and Johnson, A. 1947. Helminthosporium rostratum on corn, sorghum, and pearl millet. Phytopathology 37:180 183.

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174 BIOGRAPHICAL SKETCH Asha Marcelle Brunings completed her Bachelor of Science in Agronomy at the Anton de Kom Unive rsity of Suriname in 1993. Subsequent to working as Department Head for Research with the Victoria Agricultural Company in Suriname, Brunings pursued graduate studies at the University of Floridas Plant Molecular and Cellular Biology interdisciplinary pro gram. During 2004 2005, while finishing up her thesis, Brunings worked on the differential expression of maize pollen genes during ripening in the research program headed by Prem S. Chourey. She produced a thesis entitled In search of pathogenicity factor s of Xanthomonas citri pv. aurantifolii and graduated with a Masters degree in 2005. In the same year, Brunings began her doctorate in the Plant Pathology department under the supervision of Professor Lawrence E. Datnoff. In November 2008, Brunings succe ssfully defended her dissertation Use of Silicon in Containerized Systems and the Molecular Basis of Si licon induced Disease Resistance.