Soil Micromycetes Research Articles

Фітопатогенний мікобіом в умовах органічного виробництва сортів малини (Rubus idaeus L.) Джоан Джей і Хімбо-топ

The results of researches of influence of raspberry plant varieties on the species composition of micromycetes in rhizospheric soil and on vegetative organs of plants in the conditions of organic production are given. The mycobiota of raspberry varieties Joan J and Himbo-Top during plant ontogenesis was analyzed and the species composition of phytopathogenic micromycetes in the rhizosphere and on plant leaves was established. It was found that the population is dominated by fungi of following species: Septoria rubi, West, Botrytis cinerea, Pers, Aspergillus niger, V. Tiegh, Alternaria alternata, (Fr.) Keissl., Fusarium graminearum, Schwabe, regardless of the phase of ontogenesis of plants that produce mycotoxins, and can cause disease in animals and humans. According to the results of research, it can be assumed that in the phase of inflorescence growth in the mycobiota of rhizospheric soil and on the vegetative organs of raspberry plants of Joan J and Himbo-Top the greatest competitiveness can be characterized by isolates of fungi Septoria rubi and Alternaria alternata. The obtained results indicate a significant differentiation of the studied varieties by the reaction of interaction between plants, microorganisms and the environment. Thus, while in the mycobiota of rhizospheric soil and vegetative organs of raspberry plants of the Joan J variety during intensive fruiting of plants the isolates of Aspergillus flavus fungi were characterized by the greatest competitiveness, in Himbo-Top cultivar the highest rates of radial growth were shown by isolates of Aspergillus oryzae and Alternaria alternata

Stability of terrestrial ecosystems under the influence of steroid glycoalkaloids

Soil-transmitted helminths are one of the most pressing problems of the urban area. Worm infestations are diseases with a high (more than 50%) mortality rate among both children and adults. Therefore, one of the most pressing safety problems of not only the technosphere, but also the homosphere, is the search for methods of disinfestation of the soil cover of urban areas with a minimum load on the biota and ecological risk tending to zero. As a solution to this problem, it is proposed to use secondary plant metabolites (steroid glycoalkaloids) as a means for disinfecting various environmental objects: wastewater and their sediments, soil, sand of playgrounds, etc.The effect of various concentrations of potato juice (Solanum tuberosum) on the components of terrestrial ecosystems on the shores of water bodies: higher plants (oats (Avenum sativa)) and soil microflora (soil micromycetes Aspergillus niger, Aspergillus terrius, Alternaria alternaria, Fusarium moniliforme) was studied. Revealed moderate phytotoxicity for Avenum sativa, as well as a strong stimulatory effect for Fusarium moniliforme and Alternaria alternaria.

СОСТАВ ПОЧВЕННЫХ МИКРОМИЦЕТОВ ПРИ РАЗЛИЧНОЙ СИСТЕМЕ СОДЕРЖАНИЯ ПОЧВЫ НА ВИНОГРАДНЫХ НАСАЖДЕНИЯХ

The aim of the research was to study the composition of soil micromycetes with different systems of soil maintenance on vine plantations. The studies were carried out in the farms of Anapa district of Krasnodar Kray according to generally accepted methods in soil science and mycology. The scientific novelty lies in the insufficient knowledge of soil fungi of ampelocenoses under conditions of increased anthropogenic impact. As a result of research in 2019, it was found that the largest number of colony-forming units of micromycetes in the soil was observed in the variant with sodding. The number of КОЕ in 1 gram of absolutely dry soil in the variant with sodding in May exceeded the variant with black fallow by 5 times, and in August by 2 times. Species diversity was represented by 11 species belonging to 8 genera: Mucor, Trichoderma, Penicillium, Aspergillus, Fusarium, Alternaria, Cladosporium, Vertecillium. In the complex of the isolated micromycetes in the variant with sodding in the spring, the species of r. Trichoderma. Its frequency of occurrence was 80%. On the black fallow in this period, the dominant position was occupied by the species of the r. Penicillium (30.4%). In the summer period, in the variant with turfing, the species of the genera Fusarium, Alternaria, Cladosporium, Vertecillium were isolated with a higher frequency of occurrence, while the dominant position was occupied by species of the r. Penicillium (27.4%). In the variant with the system of soil maintenance, black fallow species dominated Penicillium and Aspergillus. The number of micromycetes in the soils of ampelocenoses depends on the system of soil maintenance and environmental conditions, while a regrouping of the species composition of fungi is observed.

Micromycetes in ampelocenosis soil under different keeping system

As a result of 2019 research it was found that the largest number of micromycetes colony-forming units in the soil was observed in the variant with sod formation. The number of CFU in 1 gram of absolutely dry soil in the variant with sod formation in May exceeded the variant with black fallow fivefold and in August twofold. Species diversity was represented by 11 species belonging to 8 genera: Mucor, Trichoderma, Penicillium, Aspergillus, Fusarium, Alternaria, Cladosporium, Vertecillium. In the complex of isolated micromycetes in the variant with sod formation during spring period the p. Trichoderma species predominated. Its occurrence frequency was 80%. On the black fallow in this period the dominant position was occupied by r. Penicillium species (30.4%). During summer period in sod formation variant the genera species Fusarium, Alternaria, Cladosporium, Vertecillium were isolated with a higher occurrence frequency, while the dominant position was occupied by p. Penicillium species (27.4%). In the variant with black fallow soil keeping system p. Penicillium and Aspergillus species predominated.

Anthropogenic Invasion of Micromycetes to Undisturbed Ecosystems of the Larsemann Hills Oasis (East Antarctica)

The Progress Station is the largest Russian Antarctic station. The anthropogenic impact on primary soils in the area of this station is reflected in the chemical structure of soils and structure of microbial communities. The article shows a multiple increase in the number of microorganisms (especially microscopic fungi) in contaminated soils around the Progress Station. The anthropogenic impact changes the structure of complexes of soil microorganisms. The proportion of mesophilic microorganisms significantly increases under these conditions. Fifty-three micromycete species of 28 genera have been identified in samples of primary soils and anthropogenic substrates. Their diversity decreases from the anthropogenic soils and anthropogenic substrates to the control (“clean”) soils. It is shown that an increase in the number of micromycete species in the area of the polar station results from the invasion of new micromycete species due to human activities. Some native species of micromycetes can adapt to anthropogenic substrates and can be destructors of different introduced materials. Over 56 and 70% among micromycetes from the contaminated soils and anthropogenic substrates, respectively, can be considered potentially pathogenic species. Therefore, invasive processes change the structure of complexes of soil micromycetes, which can serve as an indicator of anthropogenic impact on ecosystems in the Larsemann Hills oasis in East Antarctica.

Carbon Hydrolysing Enzymes of Soil Micromycetes Hydrolysing Polysaccharides of Plant Cell

Carbon Hydrolysing Enzymes of Soil Micromycetes Hydrolysing Polysaccharides of Plant Cell

Structure of seed productivity of antocians containing broad beans and features of mycoflora soil under them

Relevance. A comprehensive study of broad beans, including seed productivity and soil mycocomplexes of their anthocyanin-containing varieties, is relevant, given the need to increase the growth of crop productivity and the special contribution of micromycetes to soil phytomelioration, which is an important link in organic farming. Methods. In small-scale experiments in the city of Belgorod, varieties of beans with anthocyanins in the seed coat were studied (Bobchinsky, Karmazin, Pink Flamingo, Russian Blacks, Tsarsky Harvest, Bel-1). The selection of soil fungi was carried out by the method of soil dilutions of Waxmann, followed by deep sowing in solid nutrient media. To assess the similarity of the complexes of soil micromycetes under varieties of beans, a similarity coefficient was used. Results. Field trials of varieties of beans Vicia faba L. (Bel-1, Bobchinsky, Karmazin, Pink flamingo, Russian black, Imperial crop) containing anthocyanins in seed coatings showed that the highest yield of seeds is characteristic of the Bel-1 hybrid (65 g from a plant) and varieties Pink Flamingo (64 g), Royal Harvest (64 g). All varieties studied were characterized by a high protein content in seeds (25-31%). The main contribution to the seed productivity of these varieties of beans was made by lateral shoots (r = +0.91). Varieties of beans Bobchinsky and Tsarist Harvest can be recommended as reducing the proportion of opportunistic, allergenic and toxigenic microscopic fungi in the soil. The plants of the variety specimens Karmazin and Bel-1 were characterized by a minimal (0-9%) loss of productivity from common mycoses - alternariosis and fusariosis.

Pathocomplex of root rot of apple tree in nurseries and young orchards of the South of Russia

Root rot poses a serious threat to the main fruit crop domestic apple in nurseries and young orchards. Obtaining healthy planting material, free from root pathogens and root rot, is an especially priority task in conditions of intensive production. In the process of analyzing the affected plants from nurseries and young orchards at four sampling points, pathogens of apple root rot from 11 genera were identified and 431 isolates were extracted. The most common causative agents of apple root rot seedlings in the entire studied sample were species of the genus Fusarium spp. Soil micromycetes such as Rhizoctonia spp., Cladosporium spp., Cylinrocarpon spp., and oomycetes from the genus Pythium were rare. The composition and occurrence of species were heterogeneous at different points in the studied region. Phomopsis mali (Schulzer & Sacc.) Died., Cytospora spp., Alternaria alternate (Fr.) Keissl., and Aspergillus niger Tiegh. have been associated with root rot of seedlings and young apple trees.

Применение нового фунгицидного препарата инканон для предпосевной обработки семян при выращивании рассады томатов в искусственном грунте, полученном методом микробиологической переработки кородревесных отходов

Long-term experiments were carried out on biotechnological processing of the material of bark-wood waste of the Krasnokamsky korootval by isolated microorganisms-destructors of cellulose materials with cellulase and ligninolytic activity, as well as the use of the obtained substances as a nutrient soil for growing cultivated plants. The high efficiency of the processed material of bark-wood waste as a nutrient soil for the growth of experimental tomato plants is shown. However, it was found that without sterilizing treatment, the resulting substrate contains a significant number of soil micromycetes (up to 1010 colony-forming units per 1 g of substrate), the presence of which adversely affects the development of plants. The effectiveness of pre-sowing treatment of tomato seeds that are sensitive to a large number of micromycetes with the new Incanon drug from the class of substituted butane-1,3-dione derivatives is shown to improve the germination and survival of plants. An increase in seed germination by 14% as a result of this treatment is shown.

Phenoloxidase activity of micromycetes strains isolated from the rhizosphere of vegetable leguminous crops

Relevance. Microscopic fungi exhibit the greatest exoenzymatic activity, and xylotrophs are capable of possessing a complex of oxidase and hydrolase enzymes to destroy lignin.Methods. Among the soil micromycetes isolated from the rhizosphere of annual leguminous crops, a search was made for strains that are promising from the point of view of effective microorganism technology, in order to create optimal conditions for increasing soil fertility and crop yields. The detection of total phenol oxidase activity was carried out according to the method of Bavendamm, cultivating the strains on microbiological agar with the addition of an aromatic lignin derivative (0.06% tannin) and the growth factor was calculated. The cellulase activity of the strains was judged by the degree of hydrolysis of the filter paper. Alternaria alternata, Bipolaris, Botrytis fabae, Cunninghamella echinulata, Curvularia lunata, Macrophoma phaseolicola, Trichoderma koningii, Trichoderma viride and Ulocladium botrytis strains were found to cleave lignin and cellulose.Results. When comparing the phenoloxidase activity of the strains, it was proposed to take into account the growth factor, expressed as the ratio of the diameter of the colony on the substrate with the addition of tannin to the diameter of the colony without tannin. Thus, perspective strains of T. koningii and U. botrytis strains with respect to the complex activity of enzymes were identified. The strains C. lunata, A. alternata and B. australiensis showed high cellulase activity. The strain of non-pathogenic soil fungus C. echinulata has the ability to degrade lignin

On the Issue of Ecological Niches of Plant Pathogens in Western Siberia

This article outlines a systematic and ecological approach to the analysis of ecological niches of pathogenic plant micromycetes taking into account the achievements of general and evolutionary ecology and epiphytothiology. The regularities of the expansion of phytopathogen niches in different ecological environments are traced. The evolutionarily formed primary narrow ecological niches of soil micromycetes expand as they move to the “soil–air” boundary and air environment with the damage of plant organs. The evolutionarily formed wide ecological niches of ground–air (or leaf–stem) micromycetes expand due to the air-drop transmission mechanism under favorable hydrothermal conditions. In Western Siberia, the formation of ecological niches of pathogenic micromycetes of annual and perennial plants is at different stages of completion. The suggested evolutionary ecological classification of ecological niches of phytogathogens allows one to move from the abstract concept of ecological niche hypervolume to their specific monitoring taking into account the nature of the action of factors: evolutionary ecological (tactics R, S, T), natural, and anthropogenic in agroecosystems and natural landscapes.

Dependence of soil microbiota in apple tree plantations on moisture level and agrotechnical methods

Studies were conducted in the I. V. Michurin Federal Scientifi c Center and in its Middle Russian branch. For the fi rst time in the North-Eastern part of the Central black earth region, researches are being conducted to study the microbiota of the soil in the garden of pome crops. The aim of this research was to study the micromycetic composition of the soil in the agrocenosis of a multifactorial experience of an intensive apple orchard. Soil samples were taken in the space between rows and near-stem stripes on the sodding, in the space between rows and near-stem stripes on the fallow land. Experimental conditions: 1) control (natural conditions); 2) optimal moisture (irrigation, soil moisture 80 %); 3) waterlogging (irrigation, soil moisture 120 %). As a result of the conducted research, the dependence of the number of phytopathogenic and saprotrophic populations on the elements of agrotechnology was shown. The maximum number of the population was marked in the near-stem stripes on the fallow land and the minimal number was marked in the near-stem stripes on the sodding. The eff ect of moistening on the number of soil micromycetes was revealed. 80 % moisturized sodded space between rows and near-stem stripes, space between rows on fallow land at a humidity of 120 %, and near-stem stripes with 80 % moisture contained a high number of phytopathogens in relation to natural conditions. The greatest species diversity of the soil mycobiota was observed in the sodded near-stem stripes. A strong correlation was established from reverse close (r = -0.98) to positive close (r = 0.83) in relation to the phytopathogens and saprotrophs in the sodded row spacing; in the soil of the sodded near-stem stripes – from close negative (r = -0.90) to close positive (r = 0.92). It was noted that soil mites did not tolerate the over moistened soil, nematodes, on the contrary, were activated in soils with a humidity of 80 % and 120 % in sodded row spacing. The correlation between nematodes and soil mites in all variants remained strong (r = 0.86-0.97), closer in the control. The number of micromycete organisms in the soil was determined by a modifi ed fl otation method. In the course of research, 1 ml of distilled water was added at one of the stages, instead of a 0.1 % solution of potassium pyrophosphate; on the other, 29 ml of 0.1 % potassium pyrophosphate solution was added instead of 29 ml of distilled water.

TOXICOLOGICAL PROPERTIES OF HEAVY METALS ADSORBED ON THE SURFACE OF ACTIVATED CARBON

The article studies the effect of activated carbon with sorption capacity saturated by manganese (II) and chromium (III) ions on the vital activity of organisms and systems. Desorption of the toxic component from the surface of the sorbent occurs in accordance with the sorption equilibrium constant. This can produce a polluting effect on the water passing through carbon, on the activity of the soil microorganisms, and on the areas allocated for storage of used sorbents. The article presents new data on the effect of extracts of activated carbon saturated with manganese (II) and chromium (III) salts on the parameters of the blood of laboratory mice and the vital activity of soil microorganisms. The authors synthesized activated carbons with manganese (II) and chromium (III) ions adsorbed on the surface. The activity of alanine aminotransferase and aspartate aminotransferase and the content of total protein, albumin, urea, medium molecular weight molecules, malonic dialdehyde, and products of protein oxidation were identified in the blood of mice after oral administration of extracts of sorbents. After contact with the soil, the effect of adsorbed metals on its catalase and phosphatase activity was detected, as well as changes in the number and composition of soil microorganisms. The study demonstrated that carbons, with a sorption capacity filled by metal ions, affected some of the studied parameters. The authors recorded an increase in the number of products of lipid peroxidation and in urea content after the administration of sorbent suspensions; at the same time, a decrease in the total protein content in the blood of mice was noted. Manganese-adsorbed by carbon also causes a decrease in the number of oligonitrophilic, oligotrophic, and amylolytic groups of soil microorganisms, as well as a simplification of the generic structure of soil micromycetes due to the disappearance of rare genera of Miceliasterilia, Myrothecium.

Plastics Biodestruction under the Impact of Caves Micromycetes

The article is devoted to the analysis of the plastics biodegradation rate under the impact of micromycetes. Three types of widespread soil micromycetes were selected for the experiments. The strains of thermotolerant micromycetes (optimum growth at a temperature of 12-25°C) isolated from karst caves were used. Penicillium chrysogenum, was highlighted with gypsum sinter deposits of the Novoafonskaya cave named after G. Sh. Smyr (Abkhazia). P. nigrum, was isolated from clay deposits of Divya cave (Russia, Perm region). Sporotrichum sp. was allocated from the clay deposits of the cave Mchishta-Akshasha (Abkhazia). Four types of plastics were biodegraded: high-pressure polyethylene, polypropylene, polyethylene terephthalate, low-pressure polyethylene. The experiments were carried out in the Chapek-Dox nutrient medium in liquid and agar medium. Evaluation of the biodegradation rate was carried out by calculating the mass loss of samples. Qualitative changes in the surface were studied by using scanning electron microscopy. It was found that P. chrysogenum had the highest rate of biodegradation and P. nigrum had the lowest rate. The weight loss was the reatest in polyethylene terephthalate, lower - in polypropylene, and the lowest one – in the low-pressure polyethylene.

The Structure of Bacterial and Fungal Communities in the Rhizosphere and Root-Free Loci of Gray Forest Soil

The taxonomic composition, abundance, and diversity of bacterial and fungal communities in the rhizosphere loci and bulk mass of the gray forest soil (Eutric Retisol (Loamic, Aric, Cutanic, Humic)) under potatoes, maize, and white mustard grown with the application of mineral and organic fertilizers were compared. Among bacteria, Bacillus megaterium and Paenibacillus polymyxa species predominated in all the experimental variants. The micromycete community was represented by 39 species belonging to 19 genera. Under the impact of organic fertilizers, the abundance of Trichoderma harzianum—an antagonist of many phytopathogens—increased. A decrease in the abundance of representatives of Fusarium genus was observed both in the rhizosphere and in the bulk soil. Fertilization was the most significant factor determining the structure and diversity of micromycete communities both in the soil and rhizosphere. The application of mineral fertilizers reduced the diversity of micromycetes in soil, whereas the use of organic fertilizers increased it. In general, organic fertilizers proved to be more favorable for the rhizosphere and bulk soil mycobiomes and for the total soil suppressiveness than the mineral fertilizers.

INFLUENCE OF AGROTECHNICAL MEASURES ON THE NUMBER AND PHYSIOLOGICAL-BIOCHEMICAL ACTIVITY OF MICROORGANISMS IN GRAY FOREST SOIL

The influence of agrotechnical measures: mineral fertilization, liming, dipping of biomass ofgreen manure culture and by-products of the precursor in crop rotation on the number andphysiological-biochemical activity of microorganisms of the root zone of spring wheat was studied.It has been established that the introduction of mineral fertilizers and liming increases the numberof microorganisms of the main ecological and trophic, functional and systematic groups andimproves physiological-biochemical activity of representatives of certain groups ofmicroorganisms. The introduction of exogenous organic matter (green manure + by-products of theprecursor) allows to reduce the number of melanin-synthesizing micromycetes in gray forest soil by7.65 %, their specific content in the total number of micromycetes by 47.4 %, reduce the level ofphytotoxicity of the soil by 43.4 %. Taking into account long-term data on increasing the numberand specific content of melanin-synthesizing micromycetes in soils of contaminated ecotops, thisgroup of microorganisms can be considered as diagnostic in assessing the general level ofanthropogenic pollution of agrophytocenoses.

Laccase Production and Humic Acids Decomposition by Microscopic Soil Fungi

Laccase (para-diphenol:oxygen oxidoreductase, EC 1.10.3.2) is a phenol oxidase widespread in fungi and bacteria. In basidiomycetes, this enzyme is involved in the transformation of lignin and humic substances (HS) in soil. The role of laccases of soil ascomycetes and deuteromycetes in HS degradation is not established, and conditions of the enzyme production have been poorly studied. In the present work soil micromycetes, potential laccase producers, were isolated from typical soils of the forest, steppe, and foreststeppe zones of European Russia by plating on agar media with ABTS (2,2'-azino-bis(3-ethylbenzothiazoline- 6-sulphonic acid, sodium salt)) as the substrate. Their abundance, species composition, conditions of laccase production, and its relation to humic acids (HA) degradation in liquid and solid media were studied. Out of 68 strains isolated, 20 exhibited ABTS oxidation at initial plating on agar media. In pure cultures on agar media, oxidation was less pronounced, but in the presence of HA laccase production by some strains was higher than without HA. Significant and weak extracellular laccase production in liquid medium was observed for Acremonium murorum (Corda) W. Gams Z1710 and Botritis cinerea Pers. ex Fries Z1711, respectively. The level of laccase production by A. murorum was the same without inducers and in the presence of HA, while B. cinerea produced laccase only without inducers. No direct correlation was found between the presence of laccase and/or its activity and ability of the fungi to decolorize (degrade) HA. In liquid media active laccase producer A. murorum caused lower HA decolorization (43%) than B. cinerea (62%) and the fungi lacking extracellular laccase (54–81%). The role of micromycete oxidative systems in HA degradation requires further investigation.

The structure of micromycetes communities in crop rotations with sunflower

Research results of the of sunflower crop aftereffect on the structure of communities of soil micromycetes are presented. The species structure of the mycobiota of various links of the crop rotation, determination of favorable conditions for existence and functioning of micromycetes-decomposers providing of faster mineralization of plant sunflower residues was set out. Differences in the reaction of mycocenoses to the factor of sunflower plant residues have been revealed depending on the ways of soil tillage and vegetative crop. It was determined that the determinative effect of sunflower residues appeared as an integral part of the complex of stress factors that block the development of the dominant species in the mycocenoses. When factors are applying, preference in forming communities is given to species tolerant to stress as well as species concentrated on the plant residues.

ТАКСОНОМИЧЕСКАЯ СТРУКТУРА МИКРОМИЦЕТНЫХ СООБЩЕСТВ ПОЧВ ПОД ПОСЕВАМИ СЕЛЬСКОХОЗЯЙСТВЕННЫХ КУЛЬТУР

The paper presents data on the taxonomic composition of micromycetes in soils of agrocenoses of 7fodder and grain crops (soybean, barley, lucerne, rape, safflower, sweet clover and sainfoin). The structure of micromycete communities is given.The identification of micromycetes was performed by classical microbiological methods based onmorphological features and cultural and physiological properties. The structure of micromycete communities was estimated by the relative frequency and spatial frequency of occurrence of representativesof different genera.Main results. The filamentous fungi isolated from the investigated soils belong to the eight genera:Mucor, Aspergillus, Penicillium, Fusarium, Cladosporium, Trichoderma, Metarhizium, Beauveria. Yeastorganisms are represented by the genera Aureobasidium, Rhodotorula, Metschnikowia, Lipomyces, Candida, Saccharomyces, and Cryptococcus. Soils under agricultural crops were characterized by a smallergeneric variety compared to virgin. The main components of the fungal communities were various species of genera Penicillium, Aspergillus, Fusarium. The share of each of these genera accounted for from 13.2 to 28.8%, the frequency of occurrence was from 67 to 100%. Representatives of the genera Aureobasidium, Rhodotorula and Metschnikowia prevailed among the yeasts in both relative frequency andfrequency of occurrence.Key words: soil micromycetes, taxa, structure of communities, agrocenosis.

Comparative Analysis of the Number and Structure of the Complexes of Microscopic Fungi in Tundra and Taiga Soils in the North of the Kola Peninsula

The number, biomass, length of fungal mycelium, and species diversity of microscopic fungi have been studied in soils of the tundra and taiga zones in the northern part of the Kola Peninsula: Al-Fe-humus podzols (Albic Podzols), podburs (Entic Podzols), dry peaty soils (Folic Histosols), low-moor peat soils (Sapric Histosols), and soils of frost bare spots (Cryosols). The number of cultivated microscopic fungi in tundra soils varied from 8 to 328 thousand CFU/g, their biomass averaged 1.81 ± 0.19 mg/g, and the length of fungal mycelium averaged 245 ± 25 m/g. The number of micromycetes in taiga soils varied from 80 to 350 thousand CFU/g, the number of fungal propagules in some years reached 600 thousand CFU/g; the fungal biomass varied from 0.23 to 6.2 mg/g, and the length of fungal mycelium varied from 32 to 3900 m/g. Overall, 36 species of fungi belonging to 16 genera, 13 families, and 8 orders were isolated from tundra soils. The species diversity of microscopic fungi in taiga soils was significantly higher: 87 species belonging to 31 genera, 21 families, and 11 orders. Fungi from the Penicillium genus predominated in both natural zones and constituted 38–50% of the total number of isolated species. The soils of tundra and taiga zones were characterized by their own complexes of micromycetes; the similarity of their species composition was about 40%. In soils of the tundra zone, Mortierella longicollis, Penicillium melinii, P. raistrickii, and P. simplicissimum predominated; dominant fungal species in soils of the taiga zone were represented by M. longicollis, P. decumbens, P. implicatum, and Umbelopsis isabellina.