Cryptococcus rajasthanensis sp. nov., an anamorphic yeast species related to Cryptococcus laurentii, isolated from Rajasthan, India

Two novel anamorphic yeast strains (S-15LT and 3-C1) were isolated from the inflorescences of plants collected in two different towns in Rajasthan State, India. Sequencing of the D1/D2 domains of the large-subunit (LSU) rDNA and the internal transcribed spacer (ITS) regions suggested they are strains of the same species. Phenotypic characteristics such as the absence of fermentation, the absence of sexual structures and ballistoconidia, the assimilation of myo-inositol and d-glucuronate, and positive Diazonium blue B and urease reactions indicated that these strains belong to the genus Cryptococcus. The novel strains differed from Cryptococcus laurentii in six physiological tests and differed from other related species in more than six tests. A phylogenetic analysis of the sequences of the D1/D2 domains of the LSU rDNA and the ITS regions placed these strains in the Bulleromyces clade within the order Tremellales, with C. laurentii as their closest described relative. The novel strains showed 1.6 and 7.5 % divergence in the D1/D2 domain of the LSU rDNA and ITS regions, respectively, with respect to C. laurentii. The divergence from other species was more than 3 % for the D1/D2 domain and more than 9 % for the ITS region. On the basis of the phenotypic and molecular data, strains S-15LT and 3-C1 represent a novel species within the genus Cryptococcus, for which the name Cryptococcus rajasthanensis sp. nov. is proposed. The type strain is S-15LT (=MTCC 7075T=CBS 10406T).