Differential contribution of Clavibacter michiganensis ssp. michiganensis virulence factors to systemic and local infection in tomato.

Clavibacter michiganensis ssp. michiganensis (Cmm) causes substantial economic losses in tomato production worldwide. The disease symptoms observed in plants infected systemically by Cmm are wilting and canker on the stem, whereas blister-like spots develop in locally infected leaves.

Virulence and in planta movement of Xanthomonas hortorum pv. pelargonii are affected by the diffusible signal factor (DSF)-dependent quorum sensing system.

Xanthomonas hortorum pv. pelargonii (Xhp), the causal agent of bacterial blight in pelargonium, is the most threatening bacterial disease of this ornamental worldwide. To gain an insight into the regulation of virulence in Xhp, we have disrupted the quorum sensing (QS) genes, which mediate the biosynthesis and sensing of the diffusible signal factor (DSF).