Role of bacteria cell surface in Xanthomonas axonopodis pv. citri biofilm formation.

MALAMUD F.; ROESCHLIN R.; SICILIANO F.; ENRIQUE R.; MARANO M.R.; VOJNOV A.

Rosario

Congreso; V Congreso Argentino de Microbiología General-SAMIGE 2008; 2008

Sociedad Argentino de Microbiología General-SAMIGE

 A biofilm is a community of bacteria embedded in an extracellular matrix that can be attached to a surface. This structure isbelieved to provide protection to bacteria from environmental aggressiveness. Previous works in other microorganisms have shown that external bacterial proteins are implicated in the first steps of biofilm formation. Xanthomonas axonopodis pv. citri (Xac) is the causative agent of citrus canker. Previous work from our laboratory demonstrated that this bacterium is able to produce biofilm both in vitro and in vivo. To evaluate the participation of different external protein structures in the adhesion step we generated three different mutants: Xac fliC (flagelin gene), Xac flgE (hook gene) mutants, both involved in flagella structure, and Xac fhaB encoding a non fimbrial adhesin. In quantitative violet crystal experiments these mutants showed differences in adhesion compared to Xac wild type. We also used confocal laser scanning microscopy to analyze biofilm formation for these mutants. Differences were observed in the biofilm architecture between wildtype and mutant strain. Swimming and swarming motility experiments also showed a marked alteration. In addition, we found differential behavior and symptoms development in host plant infectionexperiments.