Mechanism of antagonist action of the promising bacterial strain 5B-1 of Bacillus subtilis on the sunflower dry rot pathogen Rhizopus oryzae Went & Prins. Geerl.

Earlier in the laboratory of biomethod of V.S. Pustovoit All-Russian Research Institute of Oil Crops, as a result of gradual screening, a promising bacterial producer strain of microbiopreparation 5B-1 Bacillus subtilis, showing antagonism to the sunflower dry rot pathogen Rhizopus oryzae Went & Prins. Geerl. was isolated. In this study, the character and dynamics of changes in the pathogen mycelium during co-culti-vation with the antagonist were studied using a light microscope. It was shown that the bacterial strain has antibiotic activity, which is expressed in the formation of spherical swellings of the apical parts of the pathogen hyphae, as well as outgrowth, thinning of the hy-phal ends, formation of giant cells, compression of the cytoplasm and discoloration of the hyphae of the sub-strate and air mycelium. At the same time, there was no destruction of mycelial cell walls of the pathogen.