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Poster: Biology & Disease Mgmt: Mycology


Preliminary results from Multilocus Sequence Typing of the soilborne fungal pathogen Sclerotium rolfsii
P. SORIA (1), M. Smith (1), N. Dufault (1) (1) University of Florida, U.S.A.

Sclerotium rolfsii is an important soilborne fungal pathogen of hundreds of plant species worldwide, including economically important crops such as tomato and peanut in the southeastern US. Currently, molecular studies are scarce for this pathogen, leading to a lack of an experimental framework to study the biology S. rolfsii using genetic methods. There is, however, evidence for significant phenotypic variation among S. rolfsii isolates in terms of virulence, growth rate, sclerotial size, and temperature tolerance. Methods of measuring genetic variation are currently limited to ambiguous mycelial compatibility groups, and few sequence analyses using the ITS (internal transcribed spacer) rDNA. To accurately characterize genetic diversity among phenotypically variable S. rolfsii populations, a more elaborate and sequence-based experimental framework is required. Multilocus Sequence Typing (MLST) was chosen as a sequence-based method for cryptic species recognition and for identifying genetic diversity of S. rolfsii in the Southeastern US. Several housekeeping genes (LSU, RPB1, RPB2, TEF, and MCM7) that are commonly used in MLST analyses were evaluated to choose the most informative loci to characterize the population structure of S. rolfsii. The resulting MLST scheme will contribute to establishing a molecular framework for this important soilborne pathogen and will increase the current understanding of the biology and epidemiology of S. rolfsii.