Yamadazyma siamensis sp. nov., Yamadazyma phyllophila sp. nov. and Yamadazyma paraphyllophila sp. nov., three novel yeast species isolated from phylloplane in Thailand and Taiwan

Four strains representing three novel anamorphic yeast species were isolated from the external surface of sugarcane leaves (DMKU-RK254T), corn leaves (DMKU-RK548T), bean leaves (K129) in Thailand and hengchun pencilwood leaves (TrB1-1T) in Taiwan. On the basis of morphological, biochemical, physiological and chemotaxonomic characteristics, the sequence analysis of the D1/D2 region of the large subunit (LSU) rRNA gene, the internal transcribed spacer (ITS) region, the actin gene (ACT1) and the elongation factor 2 gene (EF2), the four strains were determined to represent novel Yamadazyma species although formation of ascospores was not observed. Strain DMKU-RK254T was determined to be related to Candida diddensiae, Candida naeodendra and Candida kanchanaburiensis but with 1.8, 1.8 and 2.0 % nucleotide substitutions in the D1/D2 region of the LSU rRNA gene, respectively. It was assigned to Yamadazyma siamensis sp. nov. (type strain DMKU-RK254T = BCC 50730T = NBRC 108901T = CBS 12573T). The sequences of the D1/D2 region of the LSU rRNA gene, the ITS region, ACT1 gene and EF2 gene of two strains (DMKU-RK548T and K129) were identical but differed from that of strain TrB1-1T by 0.6, 1.0, 3.3 and 5.9 % nucleotide substitutions, respectively. Therefore, the two strains (DMKU-RK548T and K129) and strain TrB1-1T were assigned to be two separate species. The closest species in terms of pairwise sequences similarity of the D1/D2 region to the two novel species was Yamadazyma philogaea but with 1.1–1.7 % nucleotide substitutions. The two strains (DMKU-RK548T and K129) were assigned to Yamadazyma phyllophila sp. nov. (type strain DMKU-RK548T = BCC 50736T = NBRC 108906T = CBS 12572T) and the strain TrB1-1T was named Yamadazyma paraphyllophila sp. nov. (type strain TrB1-1T = BCRC 23030T = CCTCC AY 204005T = CBS 9928T).