• TABLE OF CONTENTS
HIDE
 Copyright
 Frenching of tobacco
 Yellow strapleaf of chrysanthe...
 YSL, Aspergillus Awentii and...
 Occurrence of Awentii in the...
 Physiology of A. wentii
 Chrysanthemum morifolium physiology...
 Conclusion






Group Title: Research report - Bradenton Agricultural Research & Education Center - GC1974-2
Title: Yellow strapleaf of chrysanthemum
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00067685/00001
 Material Information
Title: Yellow strapleaf of chrysanthemum physiology of host and pathogen(s) relative to the disease process
Series Title: Bradenton AREC research report
Physical Description: 4 leaves : ; 28 cm.
Language: English
Creator: Woltz, S. S
Agricultural Research & Education Center (Bradenton, Fla.)
Publisher: Agricultural Research & Education Center, IFAS, University of Florida
Place of Publication: Bradenton Fla
Publication Date: 1974
 Subjects
Subject: Chrysanthemums -- Florida   ( lcsh )
Chrysanthemums -- Diseases and pests -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: S.S. Woltz
General Note: Caption title.
General Note: "April, 1974."
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00067685
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: oclc - 71843290

Table of Contents
    Copyright
        Copyright
    Frenching of tobacco
        Page 1
    Yellow strapleaf of chrysanthemum
        Page 1
    YSL, Aspergillus Awentii and ANCPA
        Page 2
    Occurrence of Awentii in the environment
        Page 2
    Physiology of A. wentii
        Page 3
    Chrysanthemum morifolium physiology in YSL
        Page 3
    Conclusion
        Page 4
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida








AGRICULTURAL RESEARCH & EDUCATION CENTER
IFAS, University of Florida
Bradenton, Florida

Bradenton AREC Research Report GC-1974-2 April, 1974

YELLOW STRAPLFAF OF CHRYSANTHEMUM: PHYSIOLOGY OF HOST

AND PATHOGEN(S) RELATIVE TO THE DISEASE PROCESS

S. S. Woltz
Plant Physiologist



Yellow Strapleaf disease was first described and named in Florida in 1959. It
had been seen in Florida 5 years earlier, and since then has also been observed
elsewhere in the U.S. Studies were made at several Florida Agricultural Experi-
ment Stations to determine the cause of the disease so that control or preventive
measures could be devised. Serious attention was given to viruses, herbicides
nd micronutrient deficiencies as potential causal factors. None of these
appeared to be the basic cause.

Frenching of Tobacco

A literature search on the frenching disease of tobacco revealed a great many
similarities in the etiology of the two disorders. R. A. Steinberg, with the U.S.
Department of Agriculture, carried out sophisticated research with the tobacco
disease and found that certain forms of the amino acid protein-building unit,
isoleucine, would reproduce the natural disease syndrome. This was true for
tobacco grown in germ-free culture when small amounts of isoleucine were fed
to the plants by way of the roots. In soil, however, "very large" amounts of
isoleucine were required to produce frenching symptoms. Steinberg, who had been
specializing in nutrition of microorganisms as well as plants suspected that
Bacillus cereus found in the root zone of tobacco plants might be producing a
toxin perhaps an amino acid that would prou~e, the~ same-'fects-es, isoleucine
compounds. He, therefore, grew tobacco in clop ei AUI (@i/l^iS n of
contaminating microorganisms and then inoculated physically-separated chambers
with an isolate of Bacillus cereus. Under this aseptic (gnotobiotic) micro-culture,
he obtained symptoms of frenching due to the diffusifPofof4? 4fi n fro B. cereus
into very small plants. This aspect of the wqrk has not been extended to soil
culture except to the extent that B. cereus has been found commonly i tobacco
soils and in especially large numbers in the bnpnei. f Cw hed t bacco plants.

Yellow Strapleaf of Chrysanthemum --

Based on the results obtained by Steinberg, we applied isoleucine compounds
to the root zones of chrysanthemum plants and within a week the symptoms of the
yellow strapleaf (YSL) disease developed on new lecf growth of treated plants.
Alloisoleucine was the most effective compound of the isoleucines tested.
Experiments were conducted in various ways with Bacillus cereus and micro-
organisms isolated from root zones of yellow strapleaf plants but symptoms of the
disease were not developed. It was clearly demonstrated that the action of








AGRICULTURAL RESEARCH & EDUCATION CENTER
IFAS, University of Florida
Bradenton, Florida

Bradenton AREC Research Report GC-1974-2 April, 1974

YELLOW STRAPLFAF OF CHRYSANTHEMUM: PHYSIOLOGY OF HOST

AND PATHOGEN(S) RELATIVE TO THE DISEASE PROCESS

S. S. Woltz
Plant Physiologist



Yellow Strapleaf disease was first described and named in Florida in 1959. It
had been seen in Florida 5 years earlier, and since then has also been observed
elsewhere in the U.S. Studies were made at several Florida Agricultural Experi-
ment Stations to determine the cause of the disease so that control or preventive
measures could be devised. Serious attention was given to viruses, herbicides
nd micronutrient deficiencies as potential causal factors. None of these
appeared to be the basic cause.

Frenching of Tobacco

A literature search on the frenching disease of tobacco revealed a great many
similarities in the etiology of the two disorders. R. A. Steinberg, with the U.S.
Department of Agriculture, carried out sophisticated research with the tobacco
disease and found that certain forms of the amino acid protein-building unit,
isoleucine, would reproduce the natural disease syndrome. This was true for
tobacco grown in germ-free culture when small amounts of isoleucine were fed
to the plants by way of the roots. In soil, however, "very large" amounts of
isoleucine were required to produce frenching symptoms. Steinberg, who had been
specializing in nutrition of microorganisms as well as plants suspected that
Bacillus cereus found in the root zone of tobacco plants might be producing a
toxin perhaps an amino acid that would prou~e, the~ same-'fects-es, isoleucine
compounds. He, therefore, grew tobacco in clop ei AUI (@i/l^iS n of
contaminating microorganisms and then inoculated physically-separated chambers
with an isolate of Bacillus cereus. Under this aseptic (gnotobiotic) micro-culture,
he obtained symptoms of frenching due to the diffusifPofof4? 4fi n fro B. cereus
into very small plants. This aspect of the wqrk has not been extended to soil
culture except to the extent that B. cereus has been found commonly i tobacco
soils and in especially large numbers in the bnpnei. f Cw hed t bacco plants.

Yellow Strapleaf of Chrysanthemum --

Based on the results obtained by Steinberg, we applied isoleucine compounds
to the root zones of chrysanthemum plants and within a week the symptoms of the
yellow strapleaf (YSL) disease developed on new lecf growth of treated plants.
Alloisoleucine was the most effective compound of the isoleucines tested.
Experiments were conducted in various ways with Bacillus cereus and micro-
organisms isolated from root zones of yellow strapleaf plants but symptoms of the
disease were not developed. It was clearly demonstrated that the action of







isoleucines in producing the YSL syndrome was to act i-s antagorists of leucine
and valine when the effect of the isolc!'cincs :cs overcome by addition of these
amino acids.

YSL, Asoergillus wentii and ANCPA

A new surge of work and interest in the subject of yellow strapleaf developed
following reports from England that the fungus Aspergillus wentii cynthesizes an
analog of leucine, 1 amino-2 nitrocyclopentane-1 carboxylic acid (ANCPA) which
might also be called 2-nitrocycloleucine. ANCPA was shown to be a potent
antagonist of leucine affecting growth and development of pea (?isum rativwm).
Brian, et al., reported on the physiological effects of AICPA on various plants,
especially pea and tobacco. The syndromes were quite similar to those of
frenching of tobacco and YSL of chrysanthemum. The English workers did not
explore effects of A. wentii in soils.

Since ANCPA is a naturally-occurring antagonist of leucine, experiments were
undertaken with A. wentii and ANCPA to establish whether A. wantii might be a
natural causal agent. Pure ANCPA and AIICPA contained in filtrates from cultures
of A. wentii readily produced the characteristic, easily identified YSL syndrome.
ANCPA produced symptoms equally well whether sprayed onto plants, injected into
them, or poured onto root zones of plants growing in agricultural soil or auto-
claved media. A. wentii spore suspension was poured into germ-free verimiculite
in which Chrysanthemum morifolium seedlings were growing. These inoculated
seedlings developed severe YSL while control seedlings grew nor.ally. In recent
experiments, non-aseptic infestation of soils with A. ventli resulted in devclop-
ment of severe, lasting YSL disease indicating that A. wetii could cavCe a
problem in field culture. Research is continuing with th cbjec'tive of identifying
specific soil microorganisms and their toxins that cause natural YSL in the field.
The possibility is now presented that YSL may be caused by a bacter:c. ,c by
Bacillus cereus) or by a fungus (Aspergillus eentii) and iore dcirctly by
their individual toxins which may not be the same compound. Procr.-urs _s liable
for control of a soil-borne bacterium would differ from those for a fungus in
many respects since the physiology and adaptations of bacteria and fungi represent
two extremes for soil microflora.

Occurrence of. A.wentii in G~e Environment

While it has not been established that A. wentii is the causal agent in any
naturally-occurring plant diseases such as YSL, its very strong potential requires
evaluation.

A. wentii is cosmopolitan in its distribution, occurring in coils frol: all parts of
the world and upon a variety of organic substrates such as moist grains and
decaying vegetation. A. wentii possesses antibacterial activity which gives it
a strong competitive advantage in the soil environment. This fungus species is
capable of carrying out a great many enzymatic reaction uti.zing chcicals a-nd
materials in the environment as growth substrates. Because of the extremely large
numbers and kinds of microorganisms growing competitively in soil, the likelihood
of the rise or decline of a given species is difficult to Tredict or measure.
A. wentii is commonly found associated with the roots of pin.epple and the drug
plant Coptis japonicus and grows readily at a lcw relative h'TMCidity on organic
debris of plant or animal origin. A. wentii populations have reportedly increased







isoleucines in producing the YSL syndrome was to act i-s antagorists of leucine
and valine when the effect of the isolc!'cincs :cs overcome by addition of these
amino acids.

YSL, Asoergillus wentii and ANCPA

A new surge of work and interest in the subject of yellow strapleaf developed
following reports from England that the fungus Aspergillus wentii cynthesizes an
analog of leucine, 1 amino-2 nitrocyclopentane-1 carboxylic acid (ANCPA) which
might also be called 2-nitrocycloleucine. ANCPA was shown to be a potent
antagonist of leucine affecting growth and development of pea (?isum rativwm).
Brian, et al., reported on the physiological effects of AICPA on various plants,
especially pea and tobacco. The syndromes were quite similar to those of
frenching of tobacco and YSL of chrysanthemum. The English workers did not
explore effects of A. wentii in soils.

Since ANCPA is a naturally-occurring antagonist of leucine, experiments were
undertaken with A. wentii and ANCPA to establish whether A. wantii might be a
natural causal agent. Pure ANCPA and AIICPA contained in filtrates from cultures
of A. wentii readily produced the characteristic, easily identified YSL syndrome.
ANCPA produced symptoms equally well whether sprayed onto plants, injected into
them, or poured onto root zones of plants growing in agricultural soil or auto-
claved media. A. wentii spore suspension was poured into germ-free verimiculite
in which Chrysanthemum morifolium seedlings were growing. These inoculated
seedlings developed severe YSL while control seedlings grew nor.ally. In recent
experiments, non-aseptic infestation of soils with A. ventli resulted in devclop-
ment of severe, lasting YSL disease indicating that A. wetii could cavCe a
problem in field culture. Research is continuing with th cbjec'tive of identifying
specific soil microorganisms and their toxins that cause natural YSL in the field.
The possibility is now presented that YSL may be caused by a bacter:c. ,c by
Bacillus cereus) or by a fungus (Aspergillus eentii) and iore dcirctly by
their individual toxins which may not be the same compound. Procr.-urs _s liable
for control of a soil-borne bacterium would differ from those for a fungus in
many respects since the physiology and adaptations of bacteria and fungi represent
two extremes for soil microflora.

Occurrence of. A.wentii in G~e Environment

While it has not been established that A. wentii is the causal agent in any
naturally-occurring plant diseases such as YSL, its very strong potential requires
evaluation.

A. wentii is cosmopolitan in its distribution, occurring in coils frol: all parts of
the world and upon a variety of organic substrates such as moist grains and
decaying vegetation. A. wentii possesses antibacterial activity which gives it
a strong competitive advantage in the soil environment. This fungus species is
capable of carrying out a great many enzymatic reaction uti.zing chcicals a-nd
materials in the environment as growth substrates. Because of the extremely large
numbers and kinds of microorganisms growing competitively in soil, the likelihood
of the rise or decline of a given species is difficult to Tredict or measure.
A. wentii is commonly found associated with the roots of pin.epple and the drug
plant Coptis japonicus and grows readily at a lcw relative h'TMCidity on organic
debris of plant or animal origin. A. wentii populations have reportedly increased






in soils between forest strips planted as windbreaks. Work is under way to
decrmine frequency of occurrence of A. wentii in YSL versus non-YSL soils.
It is frequently difficult to recover the fungus from soils because of com-
petition of other microorganisms during the process of isolation. The nature
of the problem can be visualized when one considers that there are frequently
millions of cells of microorganisms per gram of soil and commonly millions of
APpergillus spp. cells per gram of slightly decomposed hay (as an example of
organic soil debris). Also, the air in comparatively "clean" environments such
as hospital wards may have as many as 2000 Aspergillus-type spores per cubic
meter (approx. 1 cu yd). In agricultural buildings where hay is handled, the
count may range from 12 to 20 million spores per cubic meter.

Physiology of A. wentii

The ubiquitous distribution of A. wentii and other strongly competitive micro-
organisms is dependent on their ability to survive and grow under adverse con-
ditions as well as their capacity to wage biochemical warfare. A. wentii has
been reported to produce an unidentified antibiotic active against bacteria,
beta-nitro-propionic acid active as a toxin, and the potent leucine antagonist
ANCPA. Experimental evidence indicates that A. wentii steadily secretes ANCPA
into the aqueous phase of the environment. ANCPA produces the YSL syndrome when
sprayed on chrysanthemums at the rate of 1 oz per 100 gal. Much lower levels are
effective when completely absorbed within the plant, i.e. injected; 1 gram is
capable of causing severe YSL in 60,000 plants (1 acre). ANCPA is also inhibitory
to seed germination and certain microorganisms.

A. wentii is capable of growth and sporulation in environments unfavorable to most
organisms, and under favorable nutrient, temperature and moisture conditions growth
can be very rapid. However, the competitive capability of an individual micro-
organism species such as A. wentii is usually surpassed by the combined effect
of microorganisms in the soil. Therefore, to obtain individual effects of a soil
microorganism on host plants, such as YSL in chrysanthemums, highly specific soil
environmental conditions must prevail.

Chrysanthemum morifolium Physiology in YSL

The effect of ANCPA or alloisoleucine in producing the YSL syndrome is primarily
that of a biochemical similar in structure to leucine (and in the case of alloiso-
leucine similar to valine) entering the chrysanthemum plant and blocking reactions
by substituting physically for the normal amino acids. The effect is not that of
a corrosive chemical or acute poison to the plant but rather a metabolic inhibitor
that limits new growth and synthesis of proteins and chlorophyll. Since loucine
and sometimes valine are "antidotes" for the YSL chemically-induced syndrome,
natural-YSL plants were sprayed with leucine (DL-2-methyl-form used because of
higher solubility) and valine. Leucine resulted in new growth and greening but
valine did not on replicated plots in chrysanthemum plantings both on the east
and west coasts of Florida. This constitutes preliminary evidence which may be of
value in identifying microorganism pathogen(s) and the toxin(s) they apparently
produce in agricultural soil. Natural amino acid antidotes are exported by
mature chrysanthemum leaves, especially when well supplied with nitrogen and other
elements that permit export of manufactured amino acids to immature plant tissue.

In YSL, new growth is severely limited, there is an accumulation of sugars and
amino acids in the plant, and older leaves become thickened with a downward leaf






in soils between forest strips planted as windbreaks. Work is under way to
decrmine frequency of occurrence of A. wentii in YSL versus non-YSL soils.
It is frequently difficult to recover the fungus from soils because of com-
petition of other microorganisms during the process of isolation. The nature
of the problem can be visualized when one considers that there are frequently
millions of cells of microorganisms per gram of soil and commonly millions of
APpergillus spp. cells per gram of slightly decomposed hay (as an example of
organic soil debris). Also, the air in comparatively "clean" environments such
as hospital wards may have as many as 2000 Aspergillus-type spores per cubic
meter (approx. 1 cu yd). In agricultural buildings where hay is handled, the
count may range from 12 to 20 million spores per cubic meter.

Physiology of A. wentii

The ubiquitous distribution of A. wentii and other strongly competitive micro-
organisms is dependent on their ability to survive and grow under adverse con-
ditions as well as their capacity to wage biochemical warfare. A. wentii has
been reported to produce an unidentified antibiotic active against bacteria,
beta-nitro-propionic acid active as a toxin, and the potent leucine antagonist
ANCPA. Experimental evidence indicates that A. wentii steadily secretes ANCPA
into the aqueous phase of the environment. ANCPA produces the YSL syndrome when
sprayed on chrysanthemums at the rate of 1 oz per 100 gal. Much lower levels are
effective when completely absorbed within the plant, i.e. injected; 1 gram is
capable of causing severe YSL in 60,000 plants (1 acre). ANCPA is also inhibitory
to seed germination and certain microorganisms.

A. wentii is capable of growth and sporulation in environments unfavorable to most
organisms, and under favorable nutrient, temperature and moisture conditions growth
can be very rapid. However, the competitive capability of an individual micro-
organism species such as A. wentii is usually surpassed by the combined effect
of microorganisms in the soil. Therefore, to obtain individual effects of a soil
microorganism on host plants, such as YSL in chrysanthemums, highly specific soil
environmental conditions must prevail.

Chrysanthemum morifolium Physiology in YSL

The effect of ANCPA or alloisoleucine in producing the YSL syndrome is primarily
that of a biochemical similar in structure to leucine (and in the case of alloiso-
leucine similar to valine) entering the chrysanthemum plant and blocking reactions
by substituting physically for the normal amino acids. The effect is not that of
a corrosive chemical or acute poison to the plant but rather a metabolic inhibitor
that limits new growth and synthesis of proteins and chlorophyll. Since loucine
and sometimes valine are "antidotes" for the YSL chemically-induced syndrome,
natural-YSL plants were sprayed with leucine (DL-2-methyl-form used because of
higher solubility) and valine. Leucine resulted in new growth and greening but
valine did not on replicated plots in chrysanthemum plantings both on the east
and west coasts of Florida. This constitutes preliminary evidence which may be of
value in identifying microorganism pathogen(s) and the toxin(s) they apparently
produce in agricultural soil. Natural amino acid antidotes are exported by
mature chrysanthemum leaves, especially when well supplied with nitrogen and other
elements that permit export of manufactured amino acids to immature plant tissue.

In YSL, new growth is severely limited, there is an accumulation of sugars and
amino acids in the plant, and older leaves become thickened with a downward leaf




-4-

roll. These are symptoms of excess sugar or carbohydrate toxicity. YSL, which
frequently first appears after a pinch of plants, is probably brought on by
pinching which temporarily retards vegetative growth. Pinching is likely to
cause an accumulation of sugars and amino acids which would then be lost by
"leakage" from the roots. The first stages of YSL are probably autocatalytic in
that free amino acids, present in affected plants in large amounts due to the
disease, can diffuse into the soil and support growth of microorganisms and
further production of an amino acid inhibitor in the soil rhizosphere for uptake
by the plant. Large amounts of ANCPA or alloisoleucine introduced into chrysanthemum
plants have very long-lasting effects apparently associated with a low rate of
destruction or alteration of these chemicals by the plants; acute naturally-
induced YSL may be very long-lasting.

Sone chrysanthemum cultivars are more susceptible than others to YSL. Two factors
that would influence this reaction would be (1) greater native capacity for
synthesis of leucjie would decrease susceptibility to YSL, and (2) faster-growing
cultivars would likely be more susceptible due to a depletion of free-leucine supply
within the plant which would render the plant more susceptible to an induced
leucine deficiency, the apparent cause of YSL expressed in terms other than those
customarily used involving the toxin.

Conclusion

This report on the present state of knowledge of the physiology of YSL emphasizes
the bringing together of information and technology from related scientific
disciplines to aid in the solution of a problem which does not fit into the
customary pattern of problems faced by the grower. The problem has yielded only
partially to solution and will require further research to provide definitive
statements of cause and control.




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