Cloning and Identification of a Pathogenicity-Related Gene xopXoo in Rice Pathogen Xanthomonas oryzae pv.oryzae

The xopX gene from Xanthomonas campestris pv.vesicatoria(Xcv) is involved in hypersensitive response induction in nonhost tabacco and enhances the susceptibility of host pepper.However,the function of the homolog with xopX revealed by the genome sequence of X.oryzae pv.oryzae(Xoo) strains MAFF311018 and KACC10311 is uncertain.To study the function of xopX homolog in Xoo,a xopXoo gene of Xoo was cloned and mutated.The xopXoo mutant induced hypersensitive response in tobacco and water soaking symptoms in rice seedlings,but its pathogenicity and reproductive capacity decreased greatly in rice leaves.Complementation of the xopXoo mutant with the xopXoo gene recovered the bacterial growth and the ability to cause the lesion length to the wild type,suggested that the xopXoo gene was related to the pathogenicity of Xoo in rice.Moreover,the products of putative genes possibly eliciting hypersensitive response in tobacco were postulated.