ATTACHMENT AND CHEMOTAXIS REACTIONS OF PHYTOPATHOGEN RHIZOBIUM RADIOBACTER IN PRESENCE OF LACTOBACILLUS PLANTARUM ISOLATED FROM PLANT SURFACES

Abstract

Lactobacillus plantarum with strong antagonistic activities are the perspective microorganisms for protection of plants against phytopathogens. The aim of the investigation was to develop the methods to study the capability of L. plantarum to inhibit crown gall agent Rhizobium radiobacter at the levels of chemotaxis to plant tissues and attachment. Materials and methods. Extracts of carrots, tomatoes and kalanchoe plants were used to observe the chemotaxis reactions. Five cultures of L. plantarum were applied as barriers between the attractant and R. radiobacter cells. A method of simultaneous cultivation of the phytopathogen and antagonist to study the competition adhesion to glass surface was proposed. Results. Effect of plant extracts on R. radiobacter chemotaxis reactions varied depending on the species of the test plant. In presence of carrot tissue liquids bacteria formed flat biofilms, tomatoes - formed microcolonies and flat biofilms, kalanchoe – strictly mushroom-like biofilms. Presence of the majority of L. plantarum antagonistic strains altered the chemotaxis reaction of R. radiobacter cells as to carrot extract towards formation of mushroom-like biofilms instead of flat ones. With application of our proposed method of simultaneous cultivation, we showed the formation of mixed biofilms of R. radiobacter and L. plantarum for the first time.Conclusion. Simple methods to study the effect of antagonistic bacteria on chemotaxis as the first stage of plant disease pathogenesis and on attachment as the second stage were proposed.