Proteomic and metabolomic analyses of Xylella fastidiosa OMV-enriched fractions reveal association with virulence factors and signaling molecules of the DSF family.

Abstract

Xylella fastidiosa releases outer membrane vesicles (OMVs) known to play a role in the systemic dissemination of this pathogen. OMVs inhibit bacterial attachment to xylem wall and traffic lipases/esterases that act on the degradation of plant cell wall. Here we extended the characterization of X. fastidiosa OMVs by identifying proteins and metabolites potentially associated with OMVs produced by Temecula1, a Pierce s disease strain, and by 9a5c and Fb7, two citrus variegated chlorosis strains. These results strengthen one of the OMVs multiple functions that is to carry determinants of virulence, such as lipases/esterases, adhesins, proteases, porins, and a pectin lyase-like protein. For the first time, we show that the two CVC strains produce XfDSF2 and CVC-DSF likewise Temecula1, and most importantly, that these compounds of the diffusible signaling factors (XfDSF) family are associated with OMV-enriched fractions. Altogether, our findings widen the potential functions of X. fastidiosa OMVs in intercellular signaling and host-pathogen interactions.