Mikologiâ i fitopatologiâ

The study of agaricoid and gasteroid fungi belonging to the class Agaricomycetes in the Penza region has been carried out beginning with 1976. Due to significant changes in the taxonomy of this group in recent decades, it became necessary to revise the materials accumulated over a 46-year research period. As a result of such a revision, it was found that in the territory of the Penza region, were recorded 837 species of agaricoid and gasteroid fungi of the class Agaricomycetes. They belong to 8 orders, 39 families and 137 genera. The largest families, including more than 50 species, are Agaricaceae, Cortinariaceae, Psathyrellaceae, Russulaceae, Strophariaceae, Tricholomataceae, from 20 to 50 species – Boletaceae, Bolbiticaeae, Crepidotaceae, Entolomataceae, Hygrophoraceae, Marasmiaceae, and Mycenaceae. The remaining families include less than 20 species each. The first place in terms of species richness is occupied by the genus Cortinarius (109 species), the second by the genus Russula (60 species). The genera uniting from 30 to 60 species are Inocybe and Mycena, from 20 to 30 species – Agaricus, Entoloma, Lactarius, Lepiota, Psathyrella, and Tricholoma, from 10 to 20 species – Amanita, Clitocybe, Conocybe, Coprinopsis, Galerina, Hebeloma, Hygrocybe, Hygrophorus, Marasmius, Melanoleuca, Panaeolus, Pholiota. The remaining genera are characterized by lower species richness levels, although they make up 82% of the total species number. Of these, 41 genera include only one species. In the course of research carried out from 2018 to 2022, a total of 27 species of Agaricomycetes new to the region were found. Three of them, Russula groenlandica, R. insignis, and R. melzeri, were noted in Russia for the first time. At the same time, 20 previously discovered species were not confirmed as a result of our revision. During observations from 1976 to 2022, it was found that the number of some species of fungi in the group under consideration is not constant and is subject to changes in the long-term regime. For example, in Agaricus xanthodermus, Caloboletus radicans, Infundibulicybe geotropa, Lactarius semisanguifluus, Lepista personata, Mutinus ravenellii and Rubinoboletus rubinus, this number increases, whereas in Floccularia luteovirens, Lactarius turpis, Leucopaxillus tricolor, Russula chloroides, and Tylopilus felleus, on the contrary, it tends to decrease.

The Aspergillus species are widespread in the environment, able to grow at high temperatures and minimal humidity, including in regions with a hot tropical climate. Some species have the potential to produce toxins. This causes the risk of contamination by fungi of the genus Aspergillus and the mycotoxins (MT) produced by them of plant materials and food products, which is possible at any stage of production, transportation and storage. In the volume of coffee imported to the Russian Federation, 85% is accounted for by raw materials (green coffee), for which the risks of mold damage remain at all stages preceding the roasting stage. It is relevant to study the species composition and toxinogenic properties of  Aspergillus spp., which contaminate food raw materials for the production of mass consumption foodstuffs. Contaminated products include coffee, which is one of the basic products of the consumer basket. Reliable data on species identification and toxigenic potential of Aspergillus spp. can be obtained only with an integrated approach based on polyphasic taxonomy. The purpose of this work is to study the species composition of fungi of the genus Aspergillus isolated from green coffee using an integrated approach based on polyphasic taxonomy. The species composition of fungi of the genus Aspergillus from the internal mycoflora of 16 samples of green coffee beans of  Arabica and Robusta. The species belonging of the isolated 34 singlspore isolates of Aspergillus spp. was determined by cultural and morphological methods and confirmed by molecular genetic analysis, i.e., RT-PCR with DNA markers of conservative sequences (ITS, CaM, β-tub), studied in vitro profile of produced secondary toxic metabolites. The dominance of species of the Niger section was established (A. niger, 90%, and  A. tubingensis, A. carbonarius); then, in decreasing order, the species of section Flavi followed (A. flavus, 100%), sections Circumdati (A. ochraceus, 40% and A. westerdijkiae, 60%). In section Fumigati there was one strain of A. fumigatus. Analysis of the profile of toxic metabolites by HPLC-MS/MS in the multi-detection mode showed the production of mycotoxins by the following species: A. niger – fumonisin B2 and ochratoxin A, A. flavus – aflatoxins B1 and B2 together with sterigmatocystin, A. westerdijkiae – ochratoxin A and penicillic acid, A. ochraceus – penicillic acid. Amounts of produced MT show a high toxinogenic potential of Aspergillus spp. Thus, 20 out of 34 strains produced significant amounts of dangerous, regulated mycotoxins: AFL B1, OTA, FB2. Non-toxinogenic isolates were represented by the species A. niger, A. carbonarius, A. tubingensis, A. flavus, and A. fumigatus. A study of the species composition and toxinogenic properties of green coffee contaminants of the genus Aspergillus using a polyphasic approach was carried out in Russia for the first time.

Determination of the role of specific genes and their products in plant resistance to stress factors, including those of a biotic nature, is an urgent task of phytopathology and provides additional information for practical use. For spring bread wheat Triticum aestivum, CAD-im genotypes (Cinnamyl alcohol dehydrogenase, cinnamyl alcohol dehydrogenase; EC 1.1.1.195) affecting leaf rust (Puccinia triticina) resistance were studied. Resistant and susceptible genotypes were grown on an infectious background and in its absence. Plant tissues were studied for a number of indicators, including the content of phenylpropanoid metabolites, as well as sterols and saponins. Phenylpropanoids show an increase in a number of metabolites due to infection, especially coniferyl acetate and synapic aldehyde. A decrease in the content of some sterols under the influence of infection in the resistant CAD^im+ ge-notype was found. It is assumed that the acetate-mevalonate pathway of metabolism in the resistant genotype CAD^im+ changes under the influence of infection from the synthesis of sterols to the synthesis of protective substances, phytoalexins.