The First Discovery of Alkali-Resistant Fungi on the Coast of Chloride Lake Baskunchak

— This is the first study of alkali-resistant fungi under the conditions of neutral salinization at Lake Baskunchak (Astrakhan region, Russia). Fungi were isolated from the lake coast chloride soils on alkaline agar medium (pH 10.0–10.5); isolates were characterized by morphological, cultural and molecular genetic features; phylogenetic analysis and analysis of adaptation to pH and salinity were performed. It has been shown that alkali-resistant fungi at the lake coast is a polyphyletic group of ascomycetes from Sordariomycetes (nine species), Dothideomycetes (five species), Eurotiomycetes (three species), and also sterile mycelium (15 isolates). The study of the growth rates in a wide range of pH values has shown that there are both alkalotolerant and alkaliphilic fungi among the isolates. The tolerance of isolates to elevated concentrations of sodium chloride was confirmed. The discovery of obligate alkaliphiles under conditions of neutral salinization was unexpected. Obligate alkaliphilic isolates were characterized as a new species of the genus Sodiomyces as a result of phylogenetic reconstructions. In the article, we discuss the possible ecological role of alkali-resistant fungi in saline habitats.