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Project titleTaxonomic diversity, spatial structure and biogeographical links of xylobiont aphyllophoroid fungi of the North-Eastern Caucasus (on the example of the Republic of Dagestan)

Keywordsbiogeography, Caucasus, Dagestan, fungi, protected areas, biodiversity, macromycetes, woody substrates

Annotation
The project is aimed at solving the fundamental problem of modern biogeography and ecology related to the study of biological diversity and community structure of xylobiont organisms in the conditions of large orographic systems of Eurasia. Wood-destroying aphyllophoroid fungi constitute a key group of wood biodestructors, which ensure the process of decomposition and humification of plant litter and the continuity of the cycle of substances and energy transformation in natural ecosystems. A number of species of xylobiont basidiomycetes are represented by mycorrhiza-forming agents or are able to show pathogenic properties in relation to woody plants. Xylotrophic fungi can also cause rot of harvested timber and treated wood, which leads to the destruction of wooden buildings and structures. The ability to decompose the lignocellulosic complexes of a woody substrate, determines not only the unique role of this group of living organisms in the functioning and maintenance of the biodiversity of forest ecosystems, but also the prospects of their use in the industrial processing of solid household waste and other cellulose-containing products. At the same time, the biodiversity of fungi in Russia has been studied extremely unevenly both in relation to individual taxa and on a territorial basis. Along with many subjects of Russia, the North-East of the Caucasus remains a “white spot” on the mycological research map. The lack of data on the distribution of various types of fungi makes it difficult not only to develop theoretical issues of biogeography, as well as related scientific disciplines, but also to solve practical problems of preserving biological diversity and monitoring pathogens. The territory of Dagestan occupies a frontier position in the resettlement of many "European" and "Asian" species of living organisms, and due to climatic features and the diversity of the relief, unique habitat conditions are formed here that can retain rare and non-occurring in other areas species of fungi. The implementation of this project will provide new knowledge about the taxonomic composition of xylobiont basidiomycetes, as well as their spatial structure and biogeographic relationships in the conditions of the North-Eastern Caucasus. The proposed project is notable for the lack of special systematic studies of xylobiont fungi in the territory to date.

Expected results
As a result of the project, for the first time, a modern species composition of xylobiont aphyllophoroid fungi in the Northeastern Caucasus will be revealed, which will close the existing gap in the understanding of their biogeographic features. The features of the taxonomic and spatial structure of the identified mycobiota, as well as the chorological features of the model species of basidiomycetes, including those previously known only from the European or Asian part of Eurasia, will be determined for the purpose of early detection and prediction of the spread of dangerous invasive fungi. It is intended to obtain a large array of new nucleotide sequences deposited in the international GenBank database for identified taxa of fungi for further use in barcoding and phylogeographic studies. Molecular phylogenetic studies of complex and poorly studied taxonomic species complexes will be carried out, which is common international practice in the study of wildlife and the description of new taxons.

Annotation of the results obtained in 2020
As a result of the second year of the study, new data on the species diversity, molecular genetic characteristics and distribution features of xylobiont aphyllophoroid fungi in the territory of the Republic of Dagestan and the Caucasus as a whole were obtained. During the expedition trips, special mycological surveys of forest ecosystems were carried out on the territory of the Dagestan Reserve within the federal state nature reserve "Tlyaratinsky" (Tlyaratinsky district, 1500-3900 m), on the territory of the national park "Samursky" (Magaramkentsky district, -15-30 m), in the vicinity of the Ersi settlement (Tabasaransky district, 690-700 m), on the territory of the nature park "Upper Gunib" (Gunibsky district, 1600-2000 m). In the course of field research the following tasks were solved: (1) an inventory of the species composition of aphyllophoroid fungi with coverage of the most diverse habitat types (in Tabasaransky and Tlyaratinsky districts); (2) collecting specimens on sample plots with regard to size characteristics and stages of woody substrate decay (Gunibsky district); (3) monitoring habitats of the protected species of aphyllophoroid fungi (Magaramkentsky district). In total, a collection of 412 herbarium specimens of fruiting bodies of aphyllophoroid fungi was gathered and processed and supplemented the main fund of the Mycological Herbarium of the BIN RAS (LE). Micromorphological study of the specimens resulted in the identification of 148 species of aphyllophoroid fungi from 14 orders of the Agaricomycetes class and 1 order of the Dacrymycetes class, including 72 species in the Gunib Plateau, 69 species in the Tlyaratinsky Reserve and 53 species in the beech forests near the Ersi settlement (Tabasaransky district). Of these, 52 species are new to the Republic of Dagestan and the North-Eastern Caucasus, including 15 species listed for the whole territory of the Caucasus for the first time. Molecular biological analysis of aphyllophoroid fungi specimens (DNA extraction, amplification, Sanger sequencing) led to 85 new nucleotide sequences of the ITS1-5.8S-ITS2 region of nrDNA during the second year of the project. The main part of the work was carried out on the equipment of the Core Facilities Center at the Komarov Botanical Institute RAS. As a result of the phylogenetic analysis, the necessary grounds were obtained and a new species of poroid fungus for science, Meruliopsis faginea Volobuev & Ismailov, the holotype of which was collected in the framework of expedition research in 2020 in Tabasaransky district of the Republic of Dagestan, was described. Molecular phylogenetic studies were performed on specimens of aphyllophoroid fungi from taxonomically complicated species complexes from the Ceriporia purpurea-group, Peniophorella praetermissa-complex and Postia caesia-complex, whose representatives were discovered in the North-East Caucasus for the first time as part of this project. Chorological features were studied and electronic distribution maps were prepared (in the QGIS software platform) for 23 model basidiomycete species. Of these, the species Boidinia parva and Postia yanae were previously known only from typical habitats located in Asia (North-Eastern China and the Republic of Sakha (Yakutia) (Russia), respectively), and the species Ceriporia torpida - only from selected regions of Europe (Czech Republic, Finland, Estonia, the territory of the Central Russian Upland (Lipetsk and Orel regions). Thus, the species compositions of groups of typically European and predominantly non-European aphyllophoroid fungi occurring in the Caucasus have been revised.

Publications

1. Crous P.W., Cowan D.A., ..., Volobuev S.V., ..., Groenewald J.Z. Fungal Planet description sheets: 1182–1283 Persoonia, - (year - 2021)

2. Volobuev S.V. A contribution to the aphyllophoroid funga (Basidiomycota) of the Tlyaratinsky protected area (Dagestan) Микология и фитопатология, - (year - 2021)

3. Volobuev S.V., Ivanushenko Yu.Yu., Ismailov A.B. Diversity and ecology of poroid fungi (Agaricomycetes, Basidiomycota) on the Gunib Plateau, Dagestan South of Russia: Ecology, Development, - (year - 2021)

Annotation of the results obtained in 2019
In the course of the first year of investigations, the species diversity of xylobiontic aphyllophoroid fungi was revealed in two protected areas of the Republic of Dagestan, the fungal species distribution was evaluated and the molecular-genetic characteristics of the identified fungal taxa were analyzed. Field studies and subsequent microscopic identification of collected specimens allowed to identify for the first time on the territory of the Gunib Plateau (inner-mountain Dagestan) 165 species of xylobiontic aphyllophoroid fungi (Agaricomycetes, Basidiomycota), 72 of which are new to Dagestan and the North-Eastern Caucasus. In addition, a survey of the Delta Samura site in the territory of the Samurskiy National Park was carried out, where 56 species of wood-inhabiting basidiomycetes were recorded, including 26 species new to Dagestan and the North-Eastern Caucasus. The high proportion of new species of aphyllophoroid fungi not previously registered for the Eastern Caucasus indicates the need to continue field studies, both to cover new habitat types and to repeat the mycological survey of already studied areas. As a result of sequencing of collected fungal specimens, 63 new ITS1-5.8S-ITS2 nrDNA sequences were obtained, which is an important step in the development of DNA barcoding techniques and the expansion of opportunities to apply molecular methods in the study of nature communities. All specimens examined by molecular biology methods are carefully documented and presented by vouchers in the Mycological Herbarium of the BIN RAS (LE). Nucleotide sequences of a number of rare species, including Auriporia aurulenta, were obtained for the first time from the territory of Russia. The results of the analysis based on the BLAST algorithm showed a 99.4% similarity to the ITS sequences from the specimens collected in the mountain habitats of the Czech Republic (GU594153) and the USA (KC585317), thus confirming the Holarctic range type of this species. All sequences obtained are prepared for depositing in the GenBank database. The revealed species diversity of xylobiontic aphyllophoroid fungi at the moment can be divided into groups: 1) Eurasian species; 2) commonly European species; 3) Mediterranean-Caucasian species; 4) mainly non-European species. The latter two groups are of the greatest interest, as the boundary position of the Caucasus between Europe and Asia determines only the probability of species presence here. This task has been initiated as a part of this study. It has been shown that the group of Mediterranean-Caucasian species is represented by Peniophora laeta, individual representatives of genera Ceriporia, Fomitopsis, etc. Their distribution is not limited to this geographical region, but is characterized by a greater number of finds in comparison with Eastern, Central or Northern Europe. Botryobasidium curtisii, described from the territory of Iran, distributed in Transcaucasia and noted in the course of the project only as the second find for Russia from the North Caucasus, can be attributed to mainly non-European species. The thematic layer "Aphyllophoroid fungi of Dagestan" was created using the QGIS software package, based on linking the identified taxa of xylobiontic aphyllophoroid fungi to fixed geographic coordinates. The studies of the first year of the project implementation not only brought new data on species composition, distribution peculiarities and molecular-genetic labeling of fungi species, but also laid the basis for further ecological and phylogeographic studies.

Publications

1. Volobuev S.V. APHYLLOPHOROID FUNGI OF THE «SAMURSKIY» NATIONAL PARK (DAGESTAN) Микология и фитопатология, - (year - 2020)

2. Volobuev S.V., Ivanushenko Yu.Yu. Aphyllophoroid fungi (Basidiomycota) on juniper in the Gunib Plateau, inner-mountain Dagestan Czech Mycology, - (year - 2020)

3. Ivanushenko Yu.Yu., Ismailov A.B., Volobuev S.V. ПЕРВЫЕ СВЕДЕНИЯ О ТРУТОВЫХ ГРИБАХ ПЛАТО ГУНИБ (РЕСПУБЛИКА ДАГЕСТАН) Материалы XXI Международной научной конференции «Биологическое разнообразие Кавказа и юга России», С. 163-166 (year - 2019)