Restriction-modification system and genetic variability of Xanthomonas oryzae pv. oryzae

;Bacterial blight caused by Xanthomonas oryzae pv. Olyzae is one of the most important diseases of rice. Host resistance, which relies on single, dominant resistance genes, is the only reliable method to control the disease at present. Pathogenic variation of the bacteria has been shown to follow the deployment of resistance genes in commercial cultivars. Information on the factors and the mechanisms for genetic variation of this pathogen is limited. Further, we have no clear evidence of whether population variability is due to sexual recombination or to variation introduced by mutations or intragenic recombination in a clonally maintained population.(omitted)itted)