大亚基rRNA基因D1/D2区序列相同或相似的子囊菌酵母ITS序列比较和核型分析

下面每个组内的酵母菌:I)Candida aaseri和Candida butyri;Ⅱ)Candida boleticola, Candida laureliae和Candida ralunensis;Ⅲ) Candida zeylanoides和Candida krissii以及Ⅳ) Pichia farinosa和Candida cacaoi因具有相同或只有一个碱基差异的大亚基(26S)rRNA基因D1/D2区序列,而被认为属于同一个种。本研究对其ITS序列和电泳核型进行了比较分析。结果表明前3个组内的种具有完全相同的ITS序列,第Ⅳ组的两个种只有1个碱基差异, 但是各组内的核型并不完全一致。第Ⅳ组内的两个种具有完全相同的核型,证实他们属于同一个种。第Ⅱ组内的C.laureliae和C.ralunensis也具有完全相同的核型,可以肯定二者也属于同一个种,该组内的C.boleticola的核型与前二者不完全一样,但染色体分子量范围相似,也可能与前二者属于同一个种。第Ⅰ和Ⅲ组内各种的核型具有明显差异,对组内种间的同物异名关系未提供支持。

ITS SEQUENCE AND ELECTROPHORETIC KARYOTYPE COMPARISONS OF THE ASCOMYCETOUS YEAST SPECIES WITH IDENTICAL OR SIMILAR LSU RRNA GENE D1/D2 DOMAIN SEQUENCES

The species in each of the following groups: Ⅰ) Candida aaseri and Candida butyri; Ⅱ) Candida boleticola, Candida laureliae and Candida ralunensis; Ⅲ) Candida zeylanoides and Candida krissii and Ⅳ)Pichiafarinosa and Candida cacaoi were considered to be conspecific because of their identical or similar (only 1 base difference) large subunit (26S) RNA gene D1/D2 domain sequences. The present study indicated that the internal transcribed spacer (ITS) sequences of the species in each of the groups were also identical or had only 1 base difference. The electrophorefic karyotyping showed that the chromosomal DNA banding profiles of the species in groups Ⅱ and Ⅳ were identical or similar. The conspecificity of the species in each of the two groups was thus confirmed. However, remarkably different electrophoretic karyotypes were found between the species in each of groups Ⅰ and Ⅲ. The taxonomic relationships of them remain to be clarified.