Effect of <i>Bacillus subtilis</i> in combination with chitosan salicylate on peroxidase and catalase activity in <i>B. sorokiniana</i> infected wheat

The aim of the work was to study the effect of Bacillus subtilis strains VKM B‑2604D and VKM B‑2605D which form the basis of the Vitaplan biological product, and their combinations with chitosan salicylate on antioxidant defense enzymes in the process of formation of resistance of wheat plants to infection with the dark brown blotch pathogen Bipolaris sorokiniana. In wheat plants treated with B. subtilis strains and their combinations with chitosan salicylate, upon subsequent infection, catalase and peroxidase are activated, which regulate the intensity of oxidative stress induced by the introduction of the pathogen. Taking into account the data obtained by us, it can be assumed that the increase in plant resistance to the pathogen is realized through the control of the activity of antioxidant enzymes (inparticular, catalase, peroxidase), which maintain the concentration of H2O2 at the level necessary for the neutralization of the phytopathogen in tissues, including the direct destruction of the invading pathogen and / or activation of crosslinking and lignification of the cell wall. These processes strengthen the cell wall and help contain the spread of the pathogen in the plant. At the same time, protective reactions are also switched on, leading to the development of induced resistance in wheat plants to dark brown spotting, which manifests itself in a decrease in the development of the disease by 25–45% relative to the infected control in the treated plants. The obtained results indicate that the combination of active strains of microorganisms-antagonists of plant pathogens and chitosan salicylate is promising for increasing the biological efficiency and expanding the spectrum of action of the developed prescription forms of biological products.