Heterogeneity of Siberian fusarioid fungi populations in phytopathogenic properties

The purpose of the work is to study the phytopathogenicity of Siberian strains of fusarium fungi (Fusarium, Neocosmospora) associated with grain crops, and their intraspecific heterogeneity in pathogenic properties. Highly toxic species have been identified F. sporotrichioides and F. oxysporum, the metabolites of which reduce the average laboratory germination of Triticum aestivum and Larix sibirica seeds by 50 % or more compared to the control. The species F. sporotrichioides and F. fujikuroi SC inhibit the development of the stem and root of wheat to an equal extent; N. solani and F. oxysporum suppress the root system to a greater extent. Intraspecific differences in the degree of phytotoxicity in relation to Zeamays seedlings and the dynamics of accumulation of metabolites for the species F. sporotrichioides, F. avenaceum, F. oxysporum, N. solani and F. fujikuroi SC are shown. Average root growth inhibition rates range from 52 to 89 %. For all strains, the phytotoxic effect increased (up to 98 %) with increasing cultivation time (14 days or more). The level of synthesis of T-2 fusariotoxin was studied for the most common species in the region, F. sporotrichioides. The maximum concentration (5.3-5.5 mg/kg) was observed in a strain isolated from barley and its monosporous crops; the toxin concentration in monoconidial clones varied from 0.94 to 5.4 mg/kg. The level of toxin synthesis in strains isolated from wheat was 0.05-0.84 mg/kg. The heterogeneity of F.sporotrichioides in terms of phytopathogenic properties was revealed: the studied strains inhibit the development of wheat within a wide range (by 36-79 % compared to the control) with the formation of necrosis with an intensity of up to 1.6 points. Monoconidial lines of F.sporotrichioides were identified, differing from the natural isolate in phytopathogenicity, mainly in the direction of its increase (growth inhibition up to 95 %, necrosis up to 2.6 points).