Yamadazyma insecticola f.a., sp. nov. and Yamadazyma epiphylla f.a., sp. nov., two novel yeast species

Abstract

Two yeast strains representing two novel yeast species were isolated from frass of an unidentified insect (ST-78T) and the external surfaces of rice leaves (YE170T) collected in Thailand. The two strains were genetically, morphologically and phenotypically distinct from recognized species and were found to represent two novel species of the genus Yamadazyma although formation of ascospores was not observed. In terms of pairwise sequence similarity of the D1/D2 region of the large subunit rRNA gene, the closest relative of strain ST-78T was Candida lessepsii CBS 9941T but with 3.8 % nucleotide substitutions, while the closest relative of strain YE170T was strain ST-78T but with 4.3 % nucleotide substitutions. Analysis of the sequences of the internal transcribed spacer 1 and 2 (ITS1–2) regions revealed that strain ST-78 differed from C. lessepsii CBS 9941T by 8.8 % nucleotide substitutions and from strain YE170T by 9.4 % nucleotide substitutions. The result of pairwise sequence similarity of the D1/D2 and ITS1–2 regions together with phylogenetic analysis indicated that strains ST-78T and YE170T represented two novel species within the Yamadazyma clade. The names Yamadazyma insecticola f.a., sp. nov. (type strain ST-78T = BCC 8314T = NBRC 110421T = CBS 13382T; MycoBank no. MB810546) and Yamadazyma epiphylla f.a., sp. nov. (type strain YE170T = BCC 63466T = NBRC 110423T = CBS 13384T; MycoBank no. MB810547) are proposed for the two novel yeast species.