Transcriptional and Translational Characterization of Rice Chitinase Genes Regulation on Superoxide anion production in Xanthomonas oryzae pv. oryzae, JXOⅢ and JXOⅤ by host-pathogen interaction Identification and preliminary comparative evaluation on resistant reactions of three sets of differential varieties to Xanthomonas oryzae pv. oryzae collected from japonica rice in Yunnan Plateau