PhoP-PhoQ Two-Component System Required for Colonization Leading to Virulence of Dickeya dadantii 3937 in planta

Dickeya dadantii (formerly Erwinia chrysanthemi, Pectobacterium chrysanthemi) is a necrotrophic, intracellular, plant pathogenic enterobacterium that induces soft rot diseases on a great variety of plants worldwide by secreting mainly multiple plant cell wall-degrading enzymes including pectinases, cellulases and proteases1. Additional factors that contribute to its pathogenicity are exopolysaccharides (EPS)2, lypopolysaccharides (LPS)3, siderophore-mediated iron transport systems4, Hrp system5, resistance to antimicrobial peptides6 and motility7. The precise roles of these virulence factors and regulation of their synthesis is often complex and responds to numerous environmental and specific signals.