The Effect of Kojic Acid, Chitosan, and Their Combinations with Bacillus subtilis Strains on the Inducing Activity of Bacillus subtilis Strains

This study examines the effects of kojic acid, chitosan, and their combinations with Bacillus subtilis strains on wheat resistance to dark brown spot. A concentration-dependent immunomodulatory effect of the acid on wheat resistance to Bipolaris sorokiniana was identified: B. subtilis VKM B-2604D and B. subtilis VKM B-2605D strains demonstrated high efficacy in protecting wheat from dark brown spot, reducing plant infestation by 50% compared to the control (80% infestation). Inclusion of kojic acid in the culture fluid of the strains at a concentration of 1.0% increased twice their immunomodulatory activity. It was established that the following compositions possessed the highest inducing activity: B. subtilis VKM B-2604D + B. subtilis VKM B-2605D CF + chitosan 0.1% + 0.5% kojic acid and B. subtilis VKM B 2604D + B. subtilis VKM B 2605D CF + chitosan 0.1% + 1.0% kojic acid. The biological activity of these compositions was 3 and 6 times higher than the effect of the original strains.