Discovery of two new Cystobasidiaceae species (Cystobasidiales, Cystobasidiomycetes) on phylloplane from western China

The fungal family Cystobasidiaceae, which includes the genera Begerowomyces, Cystobasidium, Cystastrum, Halobasidium, Robertozyma, and Queiroziella, comprises species that are predominantly associated with plants in tropical to cold regions. However, members of the genera Queiroziella and Robertozyma remain poorly studied. In the present study, fungal species were identified using a polyphasic approach combining phenotypic characterization and molecular phylogenetic analyses based on the D1/D2 domain of the large subunit (LSU) rRNA gene, the internal transcribed spacer (ITS) region, and the second largest subunit of RNA polymerase II (RPB2) gene. As a result, two novel species, Queiroziella pini sp. nov. (holotype CICC 33638T) and Robertozyma xinjiangensis sp. nov. (holotype GDMCC 2.525T), are proposed and described herein. Detailed descriptions, illustrations, and phylogenetic analyses of the novel taxa are provided, and comparisons with closely related species are presented. This study expands the known diversity of the family Cystobasidiaceae in China and provides a basis for future taxonomic and ecological investigations on this family.