MYCOBIOTA IN THE BOTTOM GROUNDS OF THE GORYACHINSKY THERMAL SPRING

Abstract

The number of colony-forming units (CFU), composition and taxonomic structure of fungal biota in the bottom grounds of the Goryachinsk geothermal spring (Buryatia, Russian Federation) were determined by the cultural approach and the method of high-performance sequencing. The number of fungi in the grounds (0–3 cm) at the outlet of the spring and the watercourse at a short distance (3–100 m) varied in the range from several units to hundreds of CFU in 1 g. 70 isolates of fungi of 34 morphotypes were isolated by platings on nutrient media, of which 15 were identified to the species and 2 to the genus level. Its were thermophilic and thermotolerant species Aspergillus fumigatus, A. niger, A. nishimurae, A. terreus, Melanocarpus albomyces, Mycothermus thermophilus, Naganishia brisbanensis, Penicillium sp., Pseudothielavia terricola, Rhodotorula sp., Scedosporium apiospermum, Talaromyces flavus, Thermomyces dupontii, Thermothielavioides terrestris and Vishniacozyma carnescens. The method of high-performance sequencing of the ITS2 rDNA site in the source soils revealed an order of magnitude greater diversity of fungi, 149 species of 132 genera, and a total of 160 species were detected by both approaches. The number of identified operational-taxonomic units (OTE) to the species was 64.4%. In addition to ascomycetes and basidiomycetes, which were detected by platings on nutrient media, DNA barcoding showed the presence of representatives of the Phylums Mucoromycota, Mortierellomycota, Zoopagomycota, Chytridiomycota, Rozellomycota in the grounds. Moreover, among the fungi established by high-performance sequencing were not only thermotolerants, but also species with different resistance to high temperatures and trophic orientation. The application of both approaches provided more detailed information about the diversity of fungal organisms in the hot spring. However, in order to identify the inhabitant species of such ecotopes, a thorough analysis of their physiological and biochemical properties (which for many taxa is absent in due to volume) and the use of other approaches are necessary.