Virulence strategies of phytopathogenic bacteria and their role in plant disease pathogenesis

Phytopathogenic bacteria have evolved several virulence strategies to face hostile environment of the host plant. In this article, we reviewed the recent progress in research on characterization of the virulence factors including secretion system with their protein effectors, toxins production, extracellular polysaccharides, growth regulators, cell wall degrading enzymes, biofilm formation, siderophores and their role in the plant infection and symptom development focusing particularly on a group of bacteria such as Erwinia amylovora, Agrobacterium tumefaciens, Pseudomonas syringae, Ralstonia solanacearum and Xanthomonas compestris that cause different plant diseases including wilts, spots, blights and cankers. The elucidation of each step in pathogenesis may constitute a key step in any design of new molecules for targeting plant pathogenic bacteria for plant disease control.