Abstract
High-altitude lakes in Tibet represent unique and underexplored reservoirs of microbial diversity. An investigation of yeast diversity in Basom Lake, a high-altitude lake in Tibet, China, led to the discovery of two novel species: Microbotryozyma lacustris sp. nov. and Cyberlindnera basumtsoensis sp. nov. Phylogenetic analyses of the ITS region and D1/D2 LSU rRNA gene sequences, complemented by phenotypic characterization, confirmed their distinct taxonomic status. Microbotryozyma lacustris represents the third species described in its genus and the first documented occurrence of Microbotryozyma in a freshwater habitat. Cyberlindnera basumtsoensis further expands the ecological diversity of the genus Cyberlindnera. This study significantly enriches the taxonomic framework of both genera and underscores the value of high-altitude lakes as reservoirs of novel yeast diversity.