YEAST COMMUNITIES ASSOCIATED WITH DIFFERENT PLANT RESOURCES IN SANDY COASTAL PLAINS OF SOUTHEASTERN BRAZIL

The distribution of yeasts was studied in different plant substrata of beach and restinga ecosystems in southeastern Brazil. Candida sonoren sis, Clavispora opuntiae, Pichia barkeri, Pichia cactophila and Geotri chum sp. were generally prevalent in yeast communities associated with necrotic tissues of the cacti Cereus pernambucensis, Selenicereus riz zini, Opuntia vulgaris and Opuntia sp. Cactus yeast communities were u nique and no cactophilic yeast species were isolated from plant substr ata other than cacti in these ecosystems. Flowers of the cactus Cereus pernambucensis had a highly specific yeast community composed almost exclusively of Pichia sp. C, a Candida domercqii-like species and Cand ida sp. C. Flowers of Ipomoea litoralis and Ipomoea pes-caprae, and ex trafloral nectaries of Senna australis and Senna bicapsularis had comm unities composed predominantly of basidiomycetous yeast anamorphs. Ins ect vectors, the chemistry of each plant resource, and environmental c onditions of these microhabitats are among the most important factors determining the species composition of these communities.