Molecular identification of ascomycetous yeasts and systematics of the genus Vanderwaltozyma

• Main Authors: Liu, Yi-Ru, 柳怡如
• Other Authors: Lee, Ching-Fu
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/58492507199676762783

碩士 === 國立新竹教育大學 === 應用科學系碩士班 === 98 === Part I: Since 2005, our lab is committed to the yeasts diversity of soil, leaves, and fruiting body of murshrooms in the mountain area of Taiwan. Some species could not be clearly identified by analysis of the D1/D2 domain of the large subunit (LSU) rRNA gene. Fifty-two strains representing 19 species were examined in this dissertation. Two more strains from different samples were included in each species. These strains are examined and delimited by sequence analysis of rDNA regions, such as the D1/D2 domain of the LSU of rRNA gene and internal transcribed spacers (ITS), and electrophoretic karyotyping. Additionally, random amplified polymorphism DNA, phenotypic and morphological characteristics are compared. As the results, fourteen species, such as Candida basidiocarpa, C. dongpuanica, C. fongbinica, C. luguana, C. molinica, C. plantae, C. renaiensis, C. rueisueiensis, C. stauntonica, C. taoyuanica, C. wulaiensis, Saturnispora dongpuana, S. sandimenana and Torulaspora terra are different from currently recognized species in the physiological and molecular characteristics, and suggested as novel species. Strains of Kazachstania sp., Candida sp. (6) and Candida sp. (10) are still ambiguous by current evidence. More molecular approaches are necessary for identification of these strains. Candida sp. (12) and Candida sp. (15) revealed similar characteristics compared to that of Candida fragi and Candida valdiviana, respectively, so they could be identified as the respective species. All the novel species will be classified in respective new taxa. Part II: Some strains identified as Vanderwsaltozyma species were collected during surveys of yeast diversity from soil in Taiwan and Thailand. These strains of Vanderwaltozyma were used to study the intra- and interspecies polymorphisms of the genus, based on sequences of the D1/D2 domain of the large subunit (LSU) of rDNA, fragments of internal transcribed spacer (ITS), and mitochondrial cytochrome c oxidase II (Cox II) gene, electrophortic karyotypes, and DNA fingerprinting with primers (GTG)5 and N21. Most of the strains can be classified into the currently accepted taxa, such as V. polyspora, V. yarrowii, V. verrucispora and V. tropicalis based on the molecular, morphological and physiological characteristics, the other three strains EN4S02, GA1S06 and GJ8S05 were different from each other in molecular characteristics and showed independent taxa from the accepted species. All the species can be differentiated from each other in the molecular characteristics, whereas they showed genetic homogeneity, such as the species of of the genus Vanderwaltozyma demonstrated ten chromosomal DNA bands ranging 350-1900 kb in electrophoretic karyotypes. The strains of V. verrucispora and V. polyspora showed intraspecies polymorphisms in electrophoretic karyotypes, DNA fingerprinting patterns, and sequences of genes listed above.