Metschnikowia saccharicola sp. nov. and Metschnikowia lopburiensis sp. nov., two novel yeast species isolated from phylloplane in Thailand

Abstract

Five strains representing two novel anamorphic yeast species were isolated from the external surface of sugarcane leaves (DMKU-RK16, DMKU-RK24, DMKU-RK198 and DMKU-RK500(T)) and rice leaf (DMKU-RK277(T)) by an enrichment technique. On the basis of morphological, biochemical, physiological and chemotaxonomic characteristics, the sequence analysis of the D1/D2 domain of the large subunit (LSU) rRNA gene and the internal transcribed spacer region, the five strains were assigned to be two novel species of the Metschnikowia, although the formation of ascospores was not observed. Four strains (DMKU-RK16, DMKU-RK24, DMKU-RK198 and DMKU-RK500(T)) where the sequences of the D1/D2 domain of the LSU rRNA gene were identical and differed by 4.1% nucleotide substitutions (20 nucleotide substitutions and four gaps out of 490 nt) from the type strain of Candida succicola, their closest known species in terms of pairwise sequence similarity, represent a single novel species, for which the name Metschnikowia saccharicola sp. nov. is proposed. The type strain is DMKU-RK500(T) (=BCC 50735(T)=NBRC 108904(T)=CBS 12575(T)). Strain DMKU-RK277(T) was closest to Candida hainanensis but with 4.0% nucleotide substitutions (18 nucleotide substitutions and three gaps out of 449 nt) in the D1/D2 domain of the LSU rRNA gene was assigned to be Metschnikowia lopburiensis sp. nov. (type strain DMKU-RK277(T)=BCC 50731(T)=NBRC 108902(T)=CBS 12574(T)).