Xanthomonas possess almost all known secretion systems (types I to VI) that play different roles in the life and disease cycle, with type III secretion system (T3SS) being the key factor of pathogenicity. Typically, "Xanthomonas" T3SS injects a cocktail of 20-30 effector proteins that interfere with plant immune system and various host cellular processes. Many of the effectors are presumably redundant as individual deletions of effector genes does not impair virulence, however mutations in T3SS apparatus has strong effect. Secretion of the effectors is coordinated with expression of other virulence factors via shared regulatory networks. The effector repertoire has been proposed to be a determinant of host specificity. "Xanthomonas" actively kill other bacterial using type IV secretion system and defend itself from amoeba using type VI secretion system.