A perspective strain 14-3 Pseudomonas chlororaphis for microbiological protection of soybean against fusarium

With the purpose to create an effective bacterial microbiopreparation, the bacterial strains of the genera Pseudomonas and Bacillus from the collection of the biomethod laboratory of VNIIMK were screened to pathogenic isolate of Fusarium sporotrichioides Sherb. As a result the most effective bacterial strain-producer of microbiopreparation 14-3 Pseudomonas chlororaphis was selected. High biological efficiency of the strain 14-3 P. chlororaphis was proved inder artificial infection with the Fusarium pathogen in laboratory conditions by the method of agar blocks (52.2%) and in soil (20.3%), as well as in the field on small experimental plots (25.7%). The strain 14-3 had a growth stimulating effect on the soybean seedlings: root length was increased on 17.5%, root weight - on 13.3%. Mechanism of action of bacterium-antagonist against phytopathogenic fungus F. sporotrichioides was studied; it presents the synthesis of antibiotic substances that destroy the pathogen mycelium in 7-10 days. The maximum number of antifungal substances in liquid culture supernatant of the strain 14-3 is formed through 72-96 hours of cultivation. The elements of the production technology and application of a prototype of the bacterial microbiopreparation on the basis of the strain-producer 14-3 P. chlororaphis were developed: deep cultivation should be carried out within 72 hours on peptone-yeast nutrient medium, Chapek or King В mediums at a temperature of 25-30 °C, medium pH should be 5-10, as sources of carbon nutrition can be used glucose, sucrose, glycerol, or molasses, as a source of nitrogen nutrition - yeast extract or peptone; the application rate for the soybean seeds processing is 2.0 liter per ton.