[Effect of plasmid composition on the chemotaxis reaction of Azospirillum brasilense Sp245 associated with gramineae].

Correlation between the loss of the 120 and/or 130 kb plasmids by the spontaneous Azospirillum brasilense mutant and appearance of the Che(-)-phenotype towards 9-mono- and disaccharides has been established. The plasmid rearrangement is concomitant with the appearance of a new 44 Kda protein among the membrane proteins of azospirilli. Chemotaxis to alanine, glutamic acid, and to organic acids is not impaired.