Molecular and phenotypic characterization of ascomycetous yeasts in hypersaline soils of Urmia Lake basin (NW Iran)

The Urmia Lake National Park (NW Iran) represents a unique ecosystem owing to special ecological conditions prevailing the region. The Urmia Lake National Park comprises a range of normal to extreme environments, with variable range of salinity between 120-300 g/L. The present study was aimed to characterize ascomycetous yeast mycobiota inhabiting hypersaline soils in this region. Soil samples were collected from different sites in Urmia Lake basin as well as islands inside the lake. Yeast isolates were recovered using Dichloran Rose Bengal agar (DRB) chloramphenicol culture medium. Pure cultures were established using routine microbiological techniques. Yeast isolates were identified based on the sequence data from the D1/D2 domain of nuclear ribosomal DNA. The present study reports six ascomycetous yeast species, viz., Meyerozyma guilliermondii, Metschnikowia sinensis, Debaryomyces hansenii, Debaryomyces subglobosus, Torulaspora delbrueckii and Candida baotianensis from soils of this region. A phylogeny inferred using sequence data based on the D1/D2 region clustered our isolates with the representative sequences for each of the species from GenBank. All of six species identified in this study, represent new records for the mycobiota of Iran. Additionally, Candida baotianensis, Debaryomyces subglobosus, Metschnikowia sinensi and Torulaspora delbrueckii are newly recorded from hypersaline soils throughout the world.