Halobasidium palustre sp. nov., Halobasidium insectorum sp. nov. and Sterigmatospora alpina sp. nov., three novel basidiomycetous yeasts in Pucciniomycotina from Europe

Seven yeast strains, isolated from an alpine peatland, plants and insect frass in Europe (Italy, Russia and Germany), were accommodated in three new species belonging to the subphylum Pucciniomycotina. Phylogenetic analyses based on sequences of the D1/D2 domains of the 26S ribosomal RNA and the internal transcribed spacer (ITS) region placed two novel species closely related to Halobasidium xiangyangense and Halobasidium phyllopilum (Cystobasidiomycetes), while a third one was found to be closely related to Sterigmatospora layueensis (Agaricostilbomycetes). The tree topology positioned the Halobasidium isolates in two distinct subclades. Physiological characterization showed that the three novel species differed from their closest relatives. Sexual structures were not observed. These new species are primarily associated with the phyllosphere. The species described here are Halobasidium palustre sp. nov. (PYCC 10024T; MycoBank MB 862292), Halobasidium insectorum sp. nov. (PYCC 10357T; MycoBank MB 862293) and Sterigmatospora alpina sp. nov. (PYCC 10025T; MycoBank MB 862295).