Vol 58, No 5 (2024)

Toxigenic fungi are pathogenic microorganisms that produce mycotoxins and cause mycoses and mycotoxicoses. According to FAO, 25% of the world’s grain production is contaminated with mycotoxins. In developing countries, up to 36% of all diseases are directly or indirectly related to fungal mycotoxins. The review considers the situation with infestation of grain crops in different regions of Russia by toxigenic fungi of the genera Claviceps, Fusarium, Alternaria, Aspergillus and Penicillium and accumulation of mycotoxins dangerous for humans and animals. Claviceps fungi are widespread on cereals, especially harmful on rye. They contain toxic alkaloids with nerve agent action. The toxins produced by Fusarium are harmful to human and animal health. Different Fusarium species can produce a wide range of mycotoxins. Fungi of the genus Alternaria are widely distributed on agricultural crops. Diseases caused by Alternaria affect usually the grain of all cereals. The main danger of grain contamination by Alternaria species is the presence of secondary metabolites toxic to plants, animals and humans in agricultural products. Fungi of the genus Aspergillus affect grain of wheat, barley, corn and other crops. Species of the genus Aspergillus produce toxins harmful to humans and animals. They have carcinogenic, mutagenic, teratogenic and immunosuppressive properties. Fungi of the genus Penicillium mainly cause seed mold. Seed mold causes reduced germination and often seed death. Fungi of the genus Penicillium produce a large number of mycotoxins. They have nephrotoxic, carcinogenic and mutagenic properties. Disease development and mycotoxin production are influenced by climatic conditions.

As a result of field work and revision of herbarium material from previous years’ collections, 14 fungal species new to the Bastak Nature Reserve were identified. Ten of them are new for the Jewish Autonomous Region (Armillaria cepistipes, Baeospora myriadophylla, Baorangia alexandri, Ceraceomyces borealis, Dichomitus squalens, Gomphidius borealis, Phlebiopsis pilatii, Picipes tubaeformis, Serpula himantioides, Thelephora penicillata). To date, 781 species of basidial macrofungi are known in the reserve mycobiota.

The article presents the results of a detailed survey of cultivated roses growing in the European territory of Russia for their infestation by fungi of the genus Phragmidium causing rose rust disease. The main study area was the rose garden of the Peter the Great Botanical Garden of BIN RAS (St. Petersburg). A total of five wild species and 43 varieties of roses from seven garden groups were studied. As a result of morphological analysis of affected plant parts, detailed microscopy (using light and scanning electron microscopes) of collected fungal specimens and analysis of DNA data, four species of the genus (Phragmidium mucronatum, P. fusiforme, P. tuberculatum, and P. rosae- pimpinellifoliae) were identified. Interestingly, all identified species appeared to belong to the group of morphologically similar species from the P. mucronatum complex. During the study, the nucleotide sequences of ITS for P. fusiforme, P. mucronatum, and P. rosae- pimpinellifoliae and LSU for P. rosae-pimpinellifoliae, previously missing from databases, were obtained for the first time. Refined morphological descriptions and illustrations of macro- and microstructures are provided for all Phragmidium species studied. To compare the studied species with other representatives of the genus and to determine their phylogenetic position, phylogenetic analysis based on ITS and LSU sequences was performed.

The xylosaprotrophic agaricomycete Pleurotus abieticola, described in 1997, is still poorly studied in ecological terms. The objective of this paper is to study the ecological characteristics of P. abieticola using the material from two large dry spruce sites (causal agent Ips typographus) in the Gladyshevsky and Shchuchye Lake protected areas (Saint Petersburg, Russia), where mass fructification of this species was found. The field species identification was confirmed by the results of ITS rDNA sequencing. A detailed study of drying stands revealed new fine features of the ecology and morphology of P. abieticola. A saprotrophic pioneer complex which includes P. abieticola has been identified (Fomitopsis pinicola, Trichaptum abietinum, Gloeophyllum sepiarium, Armillaria ostoyae, Amaropostia stiptica, Exidia nigricans, E. saccharina, Dacrymyces stillatus, Heterobasidion parviporum, Phlebiopsis gigantea, Stereum sanguinolentum). The causes of the mass distribution of Pleurotus abieticola in spruce stands affected by Ips typographus are discussed.

Data are presented on a comparative analysis of carbon-oxygen gas exchange between basidiocarps of brown and white rot fungi and the coniferous wood they decay using the chamber method at 20°C. The ratio of CO₂ and O₂ volumes (characterizing the efficiency of the oxidative conversion of organic carbon into CO₂) and CO₂ emission activity (characterizing the intensity of the oxidative conversion of organic carbon into CO₂) were assessed. It has been shown that the gas exchange of coniferous woody debris with brown and white rot is aerobic, and its carbon-oxygen balance is identical to the gas exchange of basidiocarps of the corresponding ecological and physiological groups of xylotrophic fungi and characterizes them as equally effective mineralizers: 70–80% of organic carbon is converted into CO₂. The CO₂ emission activity of woody debris with white and brown rot is close – for the former 0.11–0.12, for the latter 0.07–0.09 mg CO₂/g/h – but for white rot it is 30–60% higher. The basidiocarps of brown rot fungi are distinguished by a higher respiration rate than that of white rot fungi, but in both cases it is many times higher (white rot fungi – 5–8 times, brown rot fungi – 11–90 times) higher than the CO₂ emission activity of the wood they decay.