Possible ways of using consortium relations of Trichoderma atroviride new strain with nitrogen fixers in agrobiotechnology

Twenty-six strains of Trichoderma fungi were isolated from samples of sod-podzolic soil, bark of coniferous and deciduous trees, decaying wood, and sporocarps of basidiomycetes. The antagonistic activity of these strains was studied using samples of phytopathogenic fungi Alternaria alternata, Aureobasidium pullulans, Sclerotinia sclerotiorum, as well as 8 strains of Fusarium. Two isolates (K-01P and K-02T) of the studied Trichoderma strains showed the highest antifungal activity. Sequencing of the ITS1-5.8S-ITS2 genome region determined that these strains belong to T. atroviride and T. koningii. T. atroviride strain K-01P was selected for further studies. It showed higher degree of conidiogenesis, cellulase activity, and broad spectrum of antifungal action compared to T. koningii K-02T. The selected isolate K-01P showed a broad spectrum of antagonistic activity against micromycetes of Fusarium, Aureobasidium, Alternaria genera. Additional laboratory studies showed that the T. atroviride strain was compatible with nitrogen-fixing bacteria Azotobacter chroococcum, Rhizobium trifolii, and Fischerella muscicola. Synergism of their action and phytostimulating properties during inoculation of higher plant seeds with these associations were proved. A consortium of T. atroviride + Azotobacter chroococcum, strains was identified to have not only has growth-stimulating properties, but also the ability to degrade cellulose and dissolve phosphates at a higher level than the Trichoderma monoculture. The suspension of strain K-01P with the recommended titer of 2·105 conidia/g showed no acute toxicity in biotests using the “Ecolum” preparation based on Escherichia coli and crustaceans Daphnia magna.