Phylogenetic identification of n-alkane assimilating Candida yeasts based on nucleotide divergence in the 5 ' end of LSU rDNA gene

Phylogenetic relationships of several species within the n-alkane assimilat ing Candida yeasts were investigated by using characters from the nucleotid e sequence of the variable D1/D2 region at the 5' end of a large-subunit (2 6S) ribosomal DNA (rDNA) gene. First the nucleotide sequences of D1/D2 doma in of Candida sp. 1098 (formerly identified as C. tropicalis 1098) and its dicarboxylic acid-producing-mutant strain M1210 were investigated. These tw o nucleotide sequences were identical and lacked only one base pair compare d with that of C, maltosa CBS 5611 (type strain), and they were identified as C. maltosa, We then showed that C, maltosa IFO 1978 (formerly identified as C, cloacae) and C. maltosa IFO 1975 (formerly identified as C. subtropi calis) had the same nucleotide sequence and had only one base pair substitu tion compared with C. maltosa CBS 5611 (type strain), which is consistent w ith conventional classification. We also found that another widely studied n-alkane assimilating Candida yeast, C. tropicalis pk233, to be C, viswanat hii.