Single Insertion of the Omegon-Km Artificial Transposon into Plasmid Sp245_p02 Influences the Biogenesis of Flagella and Mechanoresponse of Azospirillum baldaniorum

Abstract— The cells of Azospirillum baldaniorum Sp245 [IBPPM 219] constitutively synthesize the polar flagellum (Fla). In response to the increasing density/viscosity of the medium, numerous lateral flagella (Laf) different from Fla emerge additionally on the surface of this bacterium. The Fla and Laf activities allow the Sp245 cells to effectively migrate under the conditions of mechanical stress. It is known that flagellin forming the filament of the polar flagellum of azospirilla is able to stimulate physiological and morphometric changes in roots and to activate plant protection against fungal infection. The results of our study show that the insertion of Omegon-Km into the flbT1 gene, encoding the protein for translational repression of the flagellin mRNA, which is localized on plasmid Sp245_p02, results not only in the Fla–, but also in the Laf– phenotype in the respective mutant of A. baldaniorum Sp245. The resulting mutant has a certain biotechnological potential, because it is characterized by the active secretion of flagellin, which is necessary for the synthesis of the polar flagellum filament, into the culture liquid.