Molecular Phylogeny and Taxonomy of Yamadazyma dushanensis f.a., sp. nov., a Cellobiose-Fermenting Yeast Species from China.

Three yeast strains of Yamadazyma dushanensis f.a., sp. nov. were isolated from rotten wood samples collected in the Dushan Forest Park, Nanyang, Henan Province, China. Sequence analyses of the D1/D2 domains of the large subunit rRNA gene and the internal transcribed spacer (ITS) regions revealed that this new species is located in the Yamadazyma clade (Debaryomycetaceae and Saccharomycetales), with three closely related species, namely, Yamadazyma terventina, Yamadazyma mexicana and Candida trypodendroni. The novel species differed from these three described species by 5-6 nt substitutions in the D1/D2 sequences. However, the ITS sequences of the new species were quite divergent from those of Y. terventina, Y. mexicana and C. trypodendroni with 12-18 nt substitutions. This new yeast species could assimilate cellobiose and other compounds related to rotting wood. The fermentation of cellobiose in Durham tubes was observed for the strains of this new yeast. The new species could also be distinguished from its closely related species, Y. terventina, Y. mexicana and C. trypodendroni, based on a number of morphological and physiological characteristics. The type strain is Y. dushanensis sp. nov. NYNU 14668 (T) (=CICC 33051(T) = CBS 13914(T)).