Metschnikowia sanitii f.a., sp. nov., a new ascomycetous yeast species isolated from mangrove forests in Thailand

Seven strains representing a novel ascomycetous yeast species were isolated from the leaf phylloplane (DMKU-SG60) and the floral surface (DMKU-FF11, DMKU-FF12, DMKU-FD2, DMKU-FD6, DMKU-FS1 and ST-387) of mangrove trees in Thailand. Pairwise sequence analysis indicated that the strains were identical or differed by one to two nucleotide substitution(s) in the D1/D2 domains of the large subunit (LSU) rRNA gene. They also were identical or differed by one to four nucleotide substitution(s) in the internal transcribed spacer (ITS) region. blast n searches of the GenBank database revealed that the closest related species was Metschnikowia rancensis , differing by 28 (5.5–6.0%) and 30–33 (8.0–8.9%) nucleotide substitutions in the D1/D2 domains of the LSU rRNA gene and the ITS region, respectively. Moreover, whole-genome sequencing was used to further confirm the separation of this species. In comparison with other related species, average nucleotide identity values of 74.6–76.5% and digital DNA–DNA hybridization values of 12.8–13.3% were obtained. Phylogenetic analysis based on the concatenated sequences of the ITS region and the D1/D2 domains of the LSU rRNA gene, as well as phylogenomic analysis, showed that these strains belong to the genus Metschnikowia , but at a distinct position relative to other recognized species. Based on molecular analyses and phenotypic characteristics, the strains represent a novel species, for which the name Metschnikowia sanitii f.a., sp. nov. is proposed. The holotype is TBRC 19861 T , and the ex-type culture is PYCC 10335 (DMKU-FF11). The MycoBank number is MB 860254.