Reclassification of the Sporobolomyces roseus and Sporidiobolus pararoseus complexes, with the description of Sporobolomyces phaffii sp. nov.

More than 50 ballistoconidium-forming yeast strains, isolated from plant leaves collected in Yunnan, China, were identified as Sporobolomyces roseus Kluyver & van Niel by conventional methods. However, comparison of the internal transcribed spacer (ITS) region and 265 rDNA D1/D2 domain sequences indicated that these strains represented more than one species. Type or authentic strains of the synonyms of Sporobolomyces roseus and the closely related species Sporidiobolus pararoseus Fell & Tallman were employed in the rDNA sequence comparison. Sporobolomyces boleticola Ramírez, Sporobolomyces pollaccii Verona & Ciferri, Sporobolomyces roseus var. madurae Janke and Torulopsis somala Verona were confirmed to be conspecific with Sporobolomyces roseus. Another synonym of this species, Sporobolomyces salmoneus Derx, was located together with Sporobolomyces marcillae Santa Maria in a separate clade. Two synonyms of Sporidiobolus pararoseus, Sporobolomyces carnicolor Yamasaki & Fujii (nom. inval.) and Sporobolomyces japonicus Iizuka & Goto, were revealed to represent two distinct species. The name Sporobolomyces carnicolor is validated, with strain CBS 4215(T) as the type strain. A novel species represented by five of the selected Yunnan strains was confirmed, for which the name Sporobolomyces phaffii sp. nov. is proposed (type strain CH 2.052(T) = AS 2.2137(T) = JCM 11491(T) = CBS 9129(T)). This study also indicates that yeast species with similar ITS sequences may have quite different D1/D2 sequences.