Monosaccharides Composition of Biofilm Produced by Xylella Fastidiosa Wild Type and Rpf Mutants

Xylella fastidiosa is a phytopathogen that produces biofilms, which are involved in its virulence and pathogenicity. Biofilms are composed of diverse compounds, including exopolysaccharides (EPSs). The EPSs are important components of biofilms that play a large role in its stability and structure. Its secretion is strongly connected to expression of the rpf (regulation of pathogenicity factor) gene cluster. To identify the monosaccharides that comprise the EPS of X! fastidiosa Temecula strain ATCC 700964, high performance liquid chromatography (HPLC) was used. The EPS produced by rpf A mutant is absent in galacturonic acid but contains a high proportion of glucose. The rpfB mutants doesnʹt present rhamnose and galacturonic acid in its EPS composition. These differences in monosaccharide composition, mainly the compared to the wild type, indicating that the rpf gene cluster is involved in biofilm formation and that these genes are more than simple regulators of the EPS production.