Citation
Setting The Mood For Raffaelea Lauricola

Material Information

Title:
Setting The Mood For Raffaelea Lauricola
Series Title:
19th Annual Undergraduate Research Symposium
Creator:
Aghajan, Keyon
Language:
English
Physical Description:
Undetermined

Subjects

Subjects / Keywords:
Center for Undergraduate Research
Genre:
Conference papers and proceedings
Poster

Notes

Abstract:
Laurel wilt, a disease caused by the fungus Raffaelea lauricola, was first reported in Georgia in 2002. Since its introduction, this disease has caused the death of nearly 500 million trees throughout the southeastern U.S. This disease affects members of the Lauraceae family, which includes species such as Persea borbonia (redbay) and Persea americana (avocado). Surveys of R. lauricola isolates and its vector, the redbay ambrosia beetle (Xyleborus glabratus), from the southeastern U.S. have shown that this pathogen and its vector are propagating clonally, which suggests that this epidemic could have been the result of a single introduction. The beetle and fungus were most likely introduced from Taiwan, where there are genetically distinct populations of R. lauricola. Although sexual reproduction of the fungus is unknown, two distinct mating types (MAT1-1 and MAT1-2) have been characterized from collections from Asia, which suggests the potential for sexual recombination. The major objective of this research was to observe whether artificial pairings of isolates representing opposite mating types would result with sexual recombination and perethicia development. Isolates of the two, opposite mating types were paired in vitro on nutrient-poor and nutrient-rich media amended with sticks of sterile wood, according to published protocols for other fungi of the Ophiostomatales. ( en )
General Note:
Research authors: Cassondra Newman, Tyler Dreaden, Andrew Loyd, Jason Smith - University of Florida
General Note:
University Scholars Program
General Note:
Faculty Mentor: Jason Smith - Forest Resources and Conservation, University of Florida

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University of Florida
Rights Management:
Copyright Cassondra Newman. Permission granted to University of Florida to digitize and display this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.

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Determination of the Reproductive Capability of the Laurel Wilt Pathogen, Raffaelea lauricola Setting the Mood for Raffaelea lauricola Cassondra Newman 1 Tyler Dreaden 2 Andrew Loyd 1 and Jason Smith 1 ; 1 School of Forest Resources and Conservation University of Florida, Gainesville, FL; 2 USDA Forest Service, Southern Research Station, Forest Health Research and Education Center, Lexington, KY Methodology Introduction Laurel wilt, a disease caused by the fungus Raffaelea lauricola was first reported in Georgia in 2002 Since its introduction, this disease has caused the death of nearly 500 million trees throughout the southeastern U S Raffaelea lauricola causes typical wilt symptoms of members in the Lauraceae family, which includes species such as Persea borbonia ( redbay ) and Persea americana (avocado ) (Figure 1 ) Surveys of R lauricola isolates and its vector, the redbay ambrosia beetle ( Xyleborus glabratus ), from the southeastern U S have shown that this pathogen and its vector are propagating clonally, which suggests that this epidemic could have been the result of a single introduction ( 2 ) The beetle and fungus were most likely introduced from Taiwan, where there are genetically distinct populations of R lauricola Although sexual reproduction of the fungus is unknown, two distinct mating types (MAT 1 1 and MAT 1 2 ) have been characterized from collections from Asia, which suggests the potential for sexual recombination (Figure 2 ) Conclusions These results suggest that the mating system in R lauricola is complex The lack of sexual compatibility and development of perithecia (fruiting body) may be contributed to an unknown environmental condition or stimulus that was not present in the mating experiments ( 1 ) Likewise, the negative results of these pairing experiments may be due to cryptic gene interactions It may be extrapolated that sexual reproduction is rare if present at all in this fungus and that it is unlikely to occur in nature Future work in elucidating the undescribed sexual reproductive stage of R lauricola should be pursued to help determine what genes contribute to its ability to cause disease It may be useful to sequence all genes that comprise the two mating idiomorphs (only MAT 1 2 1 and MAT 1 1 3 were used previously to determine the presence or absence of each mating type) More tests in artificial galleries in optimal conditions may be useful in further testing the compatibility of R lauricola isolates References 1. Van den Berg, Marco A, and Karunakaran Maruthachalam Transformation Systems in Fungi, vol. 2, Springer International Pu 2016 2. Wuest 628., apsjournals.apsnet.org Aim The major objective of this research was to determine whether artificial pairings of isolates representing opposite mating types would result in sexual recombination and perithecial development Blue Text: Mat1 2 Red Text: Mat1 1 Figure 2 Minimum spanning network tree showing genetic distance of Raffaelea lauricola isolates from a global collection Raffaelea lauricola isolate collection from four distinct populations indicated by different colored circles, as well as differentiated mating types indicated by different colored text B A C Figure 1 Laurel wilt symptoms and vector A) wilt symptoms Persea borbonia ( redbay ), B) vascular streaking symptom, and C) Xyleborus glabratus (the redbay ambrosia beetle), vector of R lauricola ( Photo credit : Jiri Hulcr ) Results Of the 120 different pairings of isolates representing opposite mating types, no combination yielded successful mating (i e no perethecial development) However, there was no inhibition when isolates grew together, which means they were vegetatively compatible Figure 3 Plating techniques A) Opposite each other on the plate, B) one mating type followed by conidial suspension of opposite mating type, C) camphor branch dissection for pairing of opposite mating type isolates, and D) a close up photo of artificial gallery where isolates were inoculated A B C D Figure 4 Microscopic analysis of pairing tests A) large conidia formed in mass along hyphae and B) coiled hyphae that developed in pairing plates after three months A B