Cryptococcus mujuensis sp. nov. and Cryptococcus cuniculi sp. nov., basidiomycetous yeasts isolated from wild rabbit faeces

Abstract

Two previously undescribed anamorphic yeasts, strains T-11T and T-26T, recovered from wild rabbit faecal pellets collected in Muju, Korea, were identified using phenotypic and molecular taxonomic methods. The isolates were characterized by the proliferation of budding cells, positive diazonium blue B and urease reactions, the presence of Q-10 as the major ubiquinone, the presence of xylose in whole-cell hydrolysates and the inability to ferment sugars. Phylogenetic analyses based on 26S rRNA gene partial sequences revealed that strain T-11T was located in the Bulleromyces clade and was related to Sirobasidium intermedium, Tremella exigua, Cryptococcus cellulolyticus and Bullera pseudoalba. Strain T-26T was located in the Mesenterica clade and was closely related to Cryptococcus sp. F6 and Cryptococcus heveanensis CBS 8976. Sequence divergence values of more than 4 % from other described Cryptococcus species, together with the phenotypic differences, showed that the isolated yeasts represent previously unrecognized members of this genus. Therefore, two novel yeast species are proposed: Cryptococcus mujuensis sp. nov., with strain T-11T (=KCTC 17231T=CBS 10308T) as the type strain, and Cryptococcus cuniculi sp. nov., with strain T-26T (=KCTC 17232T=CBS 10309T) as the type strain.