Mrakia Stelviica Sp. Nov. And Mrakia Montana Sp. Nov., Two Novel Basidiomycetous Yeast Species Isolated From Cold Environments

Five yeast strains were isolated from soil and sediments collected from Alps and Apennines glaciers during sampling campaigns carried out in summer 2007 and 2017, respectively. Based on morphological and physiological tests and on phylogenetic analyses reconstructed with ITS and D1/D2 sequences, the five strains were considered to belong to two related but hitherto unknown species within the genus Mrakia, in an intermediate position between Mrakia cryoconiti and Mrakia arctica. The names Mrakia stelviica (holotype DBVPG 10734(T)) and Mrakia montana (holotype DBVPG 10736(T)) are proposed for the two novel species and a detailed description of their morphological, physiological and phylogenetic features are presented. Both species fermented glucose, sucrose and trehalose, which is an uncommon feature in basidiomycetous yeasts, and showed septate hyphae with teliospore formation.