Rhodotorula himalayensis sp. nov., a novel psychrophilic yeast isolated from Roopkund Lake of the Himalayan mountain ranges, India.

Twenty-five psychrophilic yeasts were isolated from the soil of Roopkund Lake, Himalayas, India. Two colony morphotypes were identified and representatives of 'morphotype 1' were identified as Cryptococcus gastricus. Representatives of 'morphotype 2', namely 3AT, 4A, 4B and Rup4B, showed similar phenotypic properties and are identical with respect to the nucleotide sequence of the ITS1-5.8S rRNA gene-ITS2 region and D1/D2 domain of the 26S rRNA gene. The sequence of D1/D2 domain of 3AT shows 97.6-98.8% similarity with Rhodotorula psychrophila CBS10440T, Rhodotorula glacialis CBS10437T and Rhodotorula psychrophenolica CBS10438T and in the neighbour-joining phylogenetic tree strains; 3AT, 4A, 4B and Rup4B form a cluster with Rhodotorula glacialis and Rhodotorula psychrophila. Strains 3AT, 4A, 4B and Rup4B also differ from their nearest phylogenetic relatives in several biochemical characteristics such as in assimilation of D-galactose, L-sorbose, maltose, citrate, D-glucuronate and creatinine. Thus, based on the phylogenetic analysis and the phenotypic differences 3AT, 4A, 4B and Rup 4B are assigned the status of a new species of Rhodotorula for which the name Rhodotorula himalayensis sp. nov. is proposed with 3AT as the type strain (=CBS10539T =MTCC8336T).