Chrysozyma moheensis sp. nov., a novel psychrotolerant yeast isolated from the extremely cold region of China.

Three yeast isolates representing a novel psychrotolerant yeast species were recovered from soil collected in Mohe City, Heilongjiang Province, PR China. The phylogenetic analyses based on the D1/D2 domains of the LSU rRNA and internal transcribed spacer (ITS) region showed that the new yeast formed a well-supported clade closely related to Chrysozyma sorbariae CGMCC 2.2768T. However, the new isolate differed from C. sorbariae CGMCC 2.2768T by 8.15% sequence divergence (30 nt differences and 23 gaps out of 650 bp) in the ITS region and by 2.16% sequence divergence (9 substitutions and 4 indels over 603 bp) in the D1/D2 domain, respectively. In contrast to C. sorbariae, the novel yeast species was able to assimilate soluble starch, d-xylose, d-ribose, glycerol, succinate, myo-inositol and ethylamine hydrochloride but was unable to assimilate maltose, melezitose, inulin, d-mannitol, d-glucitol, ammonium sulphate and potassium nitrate. On the basis of these findings, the name Chrysozyma moheensis sp. nov. is proposed to accommodate strains 15A5, 13A5 and 13A6, with CCTCC AF 2021079T (MycoBank no.: MB842231) designated as the holotype.