Phylogenetic analysis of the ballistoconidium-forming yeast genus Sporobolomyces based on 18S rDNA sequences

The 18S rDNA nucleotide sequences of 25 Sporobolomyces species and five Sporidiobolus species were determined. Those of Sporobolomyces dimmenae JCM 8762(T), Sporobolomyces ruber JCM 6884(T), Sporobolomyces sasicola JCM 5979(T) and Sporobolomyces taupoensis JCM 8770(T) showed the presence of intron-like regions with lengths of 1586, 324 322 and 293 nucleotides, respectively, which were presumed to be group I introns. A total of 63 18S rDNA nucleotide sequences was analysed, including 33 published reference sequences. Sporobolomyces species and the other basidiomycetes species were distributed throughout the phylogenetic tree. The resulting phylogeny indicated that Sporobolomyces is polyphyletic. Sporobolomyces species were mainly divided into four groups within the Urediniomycetes. The groups are designated as the Sporidiales, Agaricostilbum/Bensingtonia, Erythrobasidium and subbrunneus clusters. The last group, comprising four species, Sporobolomyces coprosmicola, Sporobolomyces dimmenae, Sporobolomyces linderae and Sporobolomyces subbrunneus, forms a new and distinct cluster in the phylogenetic tree in this study.