Occurrence of the Ability to Suppress the Growth of Related Strains in Rhizobia

Abstract— Screening of 1019 strains of rhizobia Rhizobium leguminosarum and Neorhizobium galegae from the “Symbiont” collection of symbiotic rhizospheric microorganisms of the Institute of Biochemistry and Genetics, Ufa Research Center, Russian Academy of Sciences, which have been isolated from root nodules of 20 leguminous species, for the ability to suppress the growth of related strains of rhizobia was carried out. Inhibition of the growth of competing bacteria by rhizobia was shown to be rather common. On average, when grown on rich media, ~10% of rhizobial strains released antibacterial substances into the medium. At the same time, when a live culture of rhizobia was applied to the lawn of bacteria, the percentage of suppression was higher. The percentage of strains synthesizing antibacterial substances correlated also, to some extent, with the level of genetic diversity of the population of legume microsymbionts. A weak signal of impaired protein synthesis was found in the study of the mechanism of action of metabolites of 20 strains of rhizobia R. leguminosarum bv. viciae from root nodules of Lathyrus palustris and Lathyrus vernus. In other cases, the nature of the antibacterial action of bacterial metabolites could not be determined using the DualRep2 system.