Abstract:Xanthomonas campestris pv. campestris (Xcc) causes black rot on cruciferous plants and is one of the model bacteria for studying the plant-microbial interaction. The XC_3605 gene of Xcc was deleted by using a suicide plasmid pK18mobsacB to generate the mutant D3605. The exopolysaccharide production, mobility and virulence on the host plant were decreased in mutant D3605, while biofilm formation was stimulated. The altered phenotypes of the mutant could be restored by the intact XC_3605 gene carried in pLAFRJ. These results indicated that XC_3605 gene plays an important role in the pathogenicity of Xcc.