Fusarioid Fungi Associated with Woody Plants in Russia

To date, the taxonomy of fusarioid fungi has undergone significant changes due to a clarification of their taxonomic status by molecular genetic methods. As a result, new species/genera have appeared, whereas some old ones have been abolished. Information on the diversity and distribution of Fusarium species do not always correspond to the modern taxonomy and requires a thorough revision. In this study we have systematized some long-term data on the species composition and specialization of fungi associated with woody plants in Russia (Far East, Siberia, the Northwestern region, and Crimea). The molecular genetic identification of 53 isolates earlier identified as Fusarium spp. has been carried out. According to morphological characteristics, phylogenetic analysis, and ecological preferences, five species complexes of Fusarium fungi have been identified. Eleven Fusarium species (F. acuminatum, F. avenaceum, F. equiseti, F. oxysporum, F. redolens, F. reticulatum, F. sambucinum, F. sporotrichioides, F. torulosum, F. tricinctum, and F. venenatum) and 1 closely related species from the genus Neocosmospora (N. solani) have been identified. In the case of woody plants, the Fusarium tricinctum species complex has been represented by the largest number of species (F. acuminatum, F. avenaceum, F. reticulatum, F. torulosum, and F. tricinctum). The maximum number of the studied isolates (17) belongs to F. avenaceum associated with various plants growing in the whole studied areas. Seven Fusarium species and N. solani have been identified on juvenile plants characterized by the signs of tracheomycotic wilt and growing in the forest nurseries of Central and Southern Siberia; species such as F. oxysporum, F. equiseti, and N. solani have been revealed only on first-year conifer seedlings. In forest and park stands, where fusarioid fungi belong mainly to saprotrophs and endophytes, nine Fusarium species have been revealed, among which F. tricinctum, F. torulosum, F. venenatum, and F. reticulatum have not been found in pathological or seed material from the forest nurseries.