PHYLOGENETIC ANALYSIS OF BASIDIOMYCETOUS YEASTS BY MEANS OF 18S RIBOSOMAL-RNA SEQUENCES - RELATIONSHIP OF ERYTHROBASIDIUM-HASEGAWIANUM AND OTHER BASIDIOMYCETOUS YEAST TAXA

The basidiomycetous yeast genus Erythrobasidium Hamamoto, Sugiyama & K omagata, based on the type species E. hasegawianum Hamamoto et al., is characterized by filobasidiaceous basidia and the Q-10 (H-2) system a s its major ubiquinone. It is tentatively placed in the Filobasidiacea e. The molecular characterization is based on 18S ribosomal RNA sequen ce comparisons among the basidiomycetous yeasts, and the ultrastructur al characterization on the cell wall and hyphal septal pores in E hase gawianum clearly indicate a close relationship with the teliospore-for ming yeasts Rhodosporidium toruloides and Leucosporidium scottii. Our molecular phylogeny with statistical analysis suggests that the existi ng taxonomic system of basidiomycetous yeasts, based primarily on the morphology of basidia including the teliospores (probasidia), should b e revised.