Cold ecosystems, including Greenland and Svalbard, represent one of the largest biospheres on Earth. Despite the low temperatures several species of psychrophilic and psychrotolerant microorganisms thrive in this extreme environment. Basidiomycete yeasts are widely distributed in cold habitats, especially in polar regions. As part of the »Microorganisms in Warming Arctic Enviroments« project, 150 isolates of basidiomycete yeasts and yeast-like fungi were isolated from various glacial samples from Greenland and Svalbard that could not be assigned to species level using the ITS rDNA molecular barcode. Morphology, asimilation (classical and commercial Biolog tests) and fermentative abilities, formation of sexual stages or sexual compatibility, urease activity, and growth ability at different temperatures and salt concentrations, were studied on selected isolates. Aligned sequences of their ribosomal (SSU, D1/D2, ITS rDNA) and housekeeping genes (TEF1, CYT, RPB1, RPB2) were used for phylogenetic analyses, that classified the isolates into three phylogenetically related groups: two groups belonged to a recently described genus Camptobasidium, one to the circumpolar species C. gelus, and the other was recognised as yet unknown species, which we described as C. arcticum. According to the data known so far, it inhabits only glacial environments in Greenland. For the third group of isolates, dimorphic fungi with a clamped mycelium and teliospores, we proposed a new genus and species, Psychromyces glacialis.
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