Microbiota of Bottom Sediments in the Coastal Zone of Lake Baikal

摘要

The number of colony-forming units (CFUs), taxonomic structure, and species richness of fungal communities in bottom sediments of Lake Baikal at a depth from 9 to 178 m have been determined based on the culture method and high-performance sequencing of the ITS2 region of rDNA. We have identified 215 species of 138 genera, 50 orders, and 22 classes assigned to 6 phyla: Ascomycota, Basidiomycota, Mucoromycota, Mortierellomycota, Chytridiomycota, and Glomeromycota. Representatives of the phyla Chytridiomycota, Glomeromycota, and Rozellomycota are detected only by DNA barcoding. The cultural method and high-performance sequencing of the ITS2 region of rDNA enable us to reveal 77 and 146 species, respectively, and only 8 species are identified by both approaches. Most of the nucleotide sequences are not identified to the level of families and species. There are representatives of various ecological and trophic groups-saprotrophs, pathogens, and symbiotrophs-in the mycobiota of bottom sediments. These are mainly psychrotolerant organisms, and there are facultative anaerobic species among them. Changes in the taxonomic structure of fungal communities, depending on the depth, and species able to function in soils are revealed. These are, in particular, Pseudeurotium bakeri, Pseudeurotium hygrophilum, Pseudogymnoascus pannorum, Pseudogymnoascus roseus, Trichoderma hamatum, Trichoderma harzianum, Trichoderma lixii, Trichoderma polysporum, Penicillium glandicola, and Penicillium swiecickii; species of the genera Rhysophydium, Fusarium, Daldinia Mortierella, Coniochaeta, Cystobasidium,Mrakia, Rhodothorula, and Solicoccozyma; and a number of others. A collection of fungal strains isolated from bottom sediments of Lake Baikal has been created.