Vishniacozyma siamensis sp. nov., a new anamorphic tremellomycetous yeast species isolated from a mangrove forest in Thailand.

Abstract

Six strains (DMKU-SG26, DMKU-SG42, DMKU-SYM22, DMKU-RG41, DMKU-RX317 and DMKU-RGM25) representing a novel basidiomycetous yeast species were isolated from leaf surfaces of mangrove plants collected in Thailand. Pairwise sequence analysis indicated that the six strains either had identical nucleotide substitution in the D1/D2 domains of the large subunit (LSU) rRNA gene sequences or differed by one to three nucleotide(s). They also had identical or differed by one to five nucleotide substitution(s) in the internal transcribed spacer (ITS) regions. blastn searches of the GenBank database revealed that the six strains were closely related to the holotype of type strains of Vishniacozyma peneaus, V. terrae, V. phoenicis, V. taiwanica and V. europaea, but with 6-15 (1.14-2.48%) and 16-26 (5.4-8.8%) nucleotide substitutions in the D1/D2 domains of the LSU rRNA gene and the ITS regions, respectively. Phylogenetic analysis based on the concatenated sequences of the ITS regions and D1/D2 domains of the LSU rRNA gene showed that these strains are placed in the Vishniacozyma clade but were at a distinctly different position from the other recognized species of the genus. Based on the phylogenetic analysis and phenotypic characteristics, these six strains are a novel species of the genus Vishniacozyma, for which the name Vishniacozyma siamensis sp. nov. is proposed to accommodate them. The holotype is TBRC 18499^T and the ex-type culture is PYCC 10042 (=DMKU-SG26). The MycoBank number of the novel species is MB 855838.