Wickerhamomyces orientalis f.a., sp. nov.: an ascomycetous yeast species belonging to the Wickerhamomyces clade

Five closely related yeast strains were isolated from soil in Kharg Island, Persian Gulf, Iran, and from fallen fruits in Galle, Sri Lanka, during separate projects. Morphologically, the strains produced white-coloured yeast colonies, with cells that were ovoid to ellipsoidal, making branched, true hyphae and pseudohyphae. Ascospore formation was not observed. Biochemically, the strains were able to ferment d-glucose and weakly ferment d-galactose. The strains could use a wide variety of carbon sources except methanol and hexadecane. Phylogenetic analyses using combined sequences of the small ribosomal subunit and the D1/D2 domains of the LSU, as well as the internal transcribed spacer regions, suggested that these strains belong to the Wickerhamomyces clade and that together they form one strongly supported phylogenetic clade. Differences in their sequences, biochemistry and morphology suggest they are representatives of distinct species of the genus Wickerhamomyces. Therefore, the name Wickerhamomyces orientalis f.a., sp. nov. is proposed to accommodate these novel strains; the type strain is IBRC-M 30103 T (=CBS 13306 T ). The MycoBank number is MB 807323.