A survey of ballistosporic phylloplane yeasts in Baton Rouge, Louisiana
S. ALBU (1), M. C. Aime (2). (1) Louisiana State University, Baton Rouge, LA, U.S.A.; (2) Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, U.S.A.
A survey of phylloplane yeasts was conducted in Baton Rouge, Louisiana during 2011. Using the spore-fall method, the leaf surfaces of seven ferns were sampled at biweekly intervals for one year. Yeasts were pure-cultured and identified by sequencing of the internal transcribed spacer region and the D1/D2 domain of the large subunit of nuclear ribosomal DNA. 463 isolates were identified, representing 81 species spanning 12 orders and six classes in Basidiomycota. Phylogenetic analyses suggest that as many as 30 of these isolates are species new to science, many of which are Exobasidiomycetes. On average, more yeasts were recovered from young fern leaves than from senescing ones. The number of yeasts recovered from abaxial versus adaxial leaf surfaces did not differ significantly. More isolates were recovered from non-fertile leaves than from those with sori, but this difference was not statistically significant. A general trend was observed in the number of isolates recovered with respect to average monthly temperature and precipitation levels as more isolates were recovered during the hottest and driest months. By far the most commonly recovered species was <i>Sporidiobolus pararoseus</i> (Sporidiobolales, Microbotryomycetes) and we designed a rapid PCR assay to screen and identify isolates of this species. These and other results will be discussed.
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