Vol 11, No 5 (2018)

Fungi able to survive under the extreme environment of soda lakes remain poorly studied. This paper presents data on the diversity and ecophysiology of filamentous fungi inhabiting one of the most alkaline habitats of the Earth: Lake Magadi, where pH values may exceed 11–12. The lake is home to a large number of prokaryotes, which form complex communities with algae and some other eukaryotes. In this study, 22 species of filamentous fungi isolated from soil samples collected on the coastline of Lake Magadi have been characterized using a systematic approach, which includes selective isolation, an analysis of morphological traits, molecular–genetic analysis, growth experiments to determine pH and temperature preferences, and an analysis of the dependence on NaCl concentrations. According to the results, alkaline soil from the Lake Magadi coastline is colonized by fungi with differing types of adaptation to high pH values. Alkaliphilic and alkalitolerant fungi belong to different families of Ascomycetes, mainly to Plectosphaerellaceae, as well as to Onygenaceae, Trihocomaceae, and Pleosporaceae. Sodiomyces tronii and S. magadii are new obligate alkaliphilic species within the earlier monotypic genus Sodiomyces (Plectosphaerellaceae). According to the growth experiments, obligate alkaliphilic isolates demonstrate thermo- and halotolerant properties. The problems of adaptation to the external pH, possible substrate preferences, and association of alkaliphilic fungi with other organisms are discussed.

The results of a study of the more than century-long history of taxonomic and ecological structures of basidial macromycete biota in polar deserts of the Northern Hemisphere are discussed. Nowadays, 77 species of macromycetes are known from this region, 40 species of which are agaricoid fungi, 30 are aphyllophoroid, and 7 are gasteromycetes. The highest number of species is known for the Franz Josef Land archipelago and Severanya Zemlya. All the identified species of agaricoid and 86% of gasteroid fungi are native representatives from extremely high latitudes collected under natural conditions, whereas 80% of the aphyllophoroid fungi are alien elements. All alien species are able to exist in the region exclusively in human-modified habitats, colonizing anthropogenic woody and grass substrates, and they disappear with the depletion of these resources. Despite the existence of mycobiota at the limit of the global thermal gradient, a specific species complex of macromycetes that does not occur anywhere in the world is formed here. Symbiotrophic species (basidial lichens and mycorrhiza-formers) are the most adaptable to such extreme conditions. General features of the organization with Antarctic mycobiota are established. The possibility that new species will appear in the region is discussed in connection with the intensification of human economic activity and global climate change.

Results of 40-year monitoring of the agaricoid biota in four types of pine forests on Perm oblast, the southern taiga subzone, are presented. We have found that the species number of fungi in pine forests varies from 80 (sphagnum pine forest) to 194 (lichen pine forest). We have found changes in species composition and an increase in species diversity in each period of monitoring. We analyze the ecological and trophic structure and define species that are dominant in regards to the basidiome number and biomass. Despite the changes in species composition, the ecological and trophic group ratio in each forest type remains almost the same. One common feature is that mycorrhizal fungi prevail in pine forests in regards to species number (55.5–61.2% of all species in the cenosis), as well as yield (52% of all basidiomes and 94% of their total biomass). We study the relation between species diversity and productivity of microbiota with the main climatic factors. We have found that July rainfall is favorable for the fruit bearing of the agarics in a pine forest with moderate humidity in August (r_s = 0.73). In swampy cenoses, June rainfall, on the contrary, has a negative impact (r_s = −0.70).

The micromycete complex population size and taxonomic structure is determined for sediments (bottom soils) of the White Sea; species actively functioning in the littoral zone and at depths of 10–30 m are identified. The bottom-soil fungi population is pretty low (hundreds to several thousand colony-forming units (CFUs) per 1 g), while the species diversity is quite rich. In total, 70 species are identified; 90% of those are Ascomycota anamorphs (Capnodiales, Eurotiales, Hypocreales, Pleosporales, Saccharomycetales, and Incertae sedis), Zygomycota (Mucoromycota) (Mucorales and Umbelopsidales orders) constituted (8%), and the share of Basidiomycota (Agaricales order) is 2%. The actively functioning bottom-soil fungi are identified on the basis of their ability to develop on organic substrates (starch, cellulose, chitin, and pieces of laminaria thallus) and grow on seawater media at low temperatures and varying oxygen levels, i.e., under conditions similar to those observed in the studied ecotope. This fungi group includes some 20 species: Paradendryphiella salina, Acremonium tubakii, A. potronii, Pseudeurotium hygrophilum, Pseudogymnoascus pannorum, Emericellopsis sphaerospora, Oidiodendron periconioides, Parengyodontium album, Lecanicillium muscarium, and representatives of genera Tolypocladium and Sarocladium. These species are typical for marine and cold habitats; some of them are well-known chitinolytics and associates of insects and algae, and many of them are able to grow in anaerobic conditions. For some of the species (Aspergillus brasiliensis, A. sydowii, Cladosporium cladosporioides, Emericellopsis sphaerospora, Oidiodendron periconioides, Pseudeurotium hygrophilum, Tolypocladium cylindrosporum, T. tundrense, Umbelopsis vinacea, Penicillium spp., and Talaromyces spp.), this ability was discovered for the first time. Further studies are required to obtain detailed ecophysiological descriptions of marine isolates of species actively functioning in the bottom soils.

A quantitative analysis of the aphyllophoroid macromycetes of Betula complex on 207 sites of the territory of the West Siberian Plain in the range from forest tundra to forest steppe allows us to determine the width of the zone and its patterns for the biota of xylotrophic fungi. It is shown that the width and structure of the zonal xylomycocomplexes is determined, first and foremost, by climatic factors, which are characterized by an expressed hydrothermal gradient. They influence fungi directly also by the formation of the forest stand corresponding to climate. The sequence of width and zone xylomycocomplex of the region is a scale for the indication of forest vegetation conditions and parameters of the forest stand of a particular timber stand. Possibilities of indication are expanded with the differentiation of the xylomycocomplex and, respectively, its width and zone scale on functional fractions of fungi (stem, peripheral, and wound types). The scale is used for assessing the condition of woods in the Numto Natural Park (northern taiga). For the characteristic of each site, coefficients of correlation of numerical structure of this mycocenos and the zone xylomycocomplex in the range from the forest tundra to the forest steppe were obtained and calculated for functional groups. The configuration of the growth spectral curves obtained in this way and their mutual position indicates the peculiarities of the hydrothermal regime of a plot; the influence of mechanical damages on tree stands; and their physiological conditions, completeness, quality, and age. It is shown that, according to the results of mycological indication, forest conditions of the Numto National Park forest plots damaged by fires and clearcuttings correspond to forest conditions of the zones to the south of the park. Regularities of the West Siberian latitude and zone xylomycological scale are characterized by a certain universality for the forest biome of Siberia, which is confirmed by similar regularities obtained during a study of elevation and zone distribution of the xylomycocomplex of Transbaikalia.