Taxonomical position of pigmented yeast isolated from Antarctic ecosystems

Abstract

Aim. To determine species composition and taxonomic position of extremotolerant Antarctic yeast. Methods. The objects of research were yeast from Antarctic soils and phytocenosis, which are stored in the Collection of Extremophilic Microorganisms at the Institute of Microbiology and Virology of the National Academy of Sciences of Ukraine, Kiev. Yeast were grown on malt wort (рН 5.0–5.5, temperature 18–20°С). Isolation of genomic DNA was performed using a commercial kit DNA-sorb; amplification of DNA preparations – use of primers NL1 and NL4; phylogenetic analysis – construction of dendrograms showing the position of the studied strains among closely related and typical species. Results. The analysis have shown a high percentage of similarity (98.4–99.9 %) of 18S rRNA genes sequences of yeast Antarctic strains and yeast sequences from the database GenBank. It was found that yeast strains belonged to phylum Basidiomycota (genera Rhodosporidium, Rhodotorula) and Ascomycota (genus Exophiala). Conclusions. As it was shown by phylogenetic analysis, red yeast S33, S48, S182 clustered with Rhodotorula mucilaginosa; S14 – with Rhodosporidium diobovatum and can be attributed to these species. Extremotolerant black yeast S10, S36 and S237 refer to the species Exophiala nigra. Keywords:Antarctica, extremotolerant yeast, phylogenetic analysis, species composition.