Department of Microbiology, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand.
Antonie Van Leeuwenhoek. 2013 Nov;104(5):637-44. doi: 10.1007/s10482-013-9971-8. Epub 2013 Jul 23.
Three strains representing one novel yeast species were isolated from the phylloplanes of the vetiver grasses (DMKU-LV90 and DMKU-LV99(T)) and sugarcane (DMKU-SP260) collected in Thailand by leaf washing followed by a plating technique. On the basis of morphological, biochemical, physiological and chemotaxonomic characteristics and the sequence analysis of the D1/D2 region of the large subunit (LSU) rRNA gene and the internal transcribed spacer region (ITS), the three strains were found to represent a single novel anamorphic ustilaginomycetous yeast species in the genus Pseudozyma. The name Pseudozyma vetiver sp. nov. is proposed for this novel species. The type strain is DMKU-LV99(T) (BCC 61021 = CBS 12824). The novel species showed phylogenetic relationships to the other members of the genus Pseudozyma and to teleomorphic fungal genera, namely Ustilago, Sporisorium and Anomalomyces in Ustilaginaceae, Ustilaginales. The three strains showed identical sequences both in the D1/D2 and ITS regions. The Pseudozyma species closest to the novel species in terms of pairwise sequence similarity in the D1/D2 region was Pseudozyma pruni but with 2.3 % nucleotide substitutions (14 nucleotide substitutions and no gaps out of 606 nt). The novel species and P. pruni differed by 10.9 % nucleotide substitutions (75 nucleotide substitutions and 31 gaps out of 691 nt) in the ITS region. The phylogenetic analysis based on the combined sequences of the ITS region and the D1/D2 region of the LSU rRNA gene showed that the novel species was found to be most closely related to Pseudozyma fusiformata but with 2.9 % nucleotide substitutions in the D1/D2 region and 7.4 % nucleotide substitutions in the ITS region.
从泰国采集的香根草（DMKU-LV90 和 DMKU-LV99(T)）和甘蔗（DMKU-SP260）的叶片上，通过叶片冲洗和划线技术分离到三株代表一个新型酵母种的菌株。根据形态学、生物化学、生理学和化学分类学特征以及大亚基（LSU）rRNA 基因的 D1/D2 区和内部转录间隔区（ITS）序列分析，这三株菌代表了假丝酵母属中的一个新型无性枝孢酵母种。建议将该新种命名为假丝酵母香根草种。模式株为 DMKU-LV99(T)（BCC 61021 = CBS 12824）。该新种与假丝酵母属的其他成员以及 Ustilaginaceae、Ustilaginales 中的有性真菌属，即黑麦喙孢属、黑粉菌属和异黑粉菌属，在系统发育上有亲缘关系。三株菌在 D1/D2 和 ITS 区均具有相同的序列。在 D1/D2 区的序列相似性方面，与新种最接近的假丝酵母种是李叶假丝酵母，但核苷酸替换率为 2.3%（606 个核苷酸中有 14 个核苷酸替换，无空位）。新种与李叶假丝酵母在 ITS 区的核苷酸替换率为 10.9%（691 个核苷酸中有 75 个核苷酸替换，31 个空位）。基于 ITS 区和 LSU rRNA 基因 D1/D2 区联合序列的系统发育分析表明，新种与拟梭孢假丝酵母关系最为密切，但在 D1/D2 区的核苷酸替换率为 2.9%，在 ITS 区的核苷酸替换率为 7.4%。
