Analysis of differentially expressed genes in Oryza meyeriana in response to infection by Xanthomonas oryzae pv. oryzae

P>Oryza meyeriana Baill was found immune to Xanthomonas oryzae pv. oryzae (Xoo). However, the genes responsible for the strong resistance are unknown. In this study, suppression subtractive hybridization (SSH) was utilized to identify genes differentially expressed in O. meyeriana after Xoo infection. Oryza meyeriana plants inoculated with high pathogenicity races were used as 'tester' and non-inoculated plants as 'driver'. Analysis of the SSH library revealed genes responsible for cell wall lignifications, which may function to block pathogen invasion. Also identified are genes involved in secondary metabolism systems to eliminate damage caused by chemicals such as peroxides in cells. One of the response genes, ME281 encoding a protein with leucine-rich repeats which has high similarity with those of other reported disease resistance genes, was further analysed by RT-PCR and Northern blotting, which showed its expression peaked at 48-72 h after Xoo infection, suggesting that it may function at the later stage of the plant's responses. This study would help demonstrate the molecular mechanism of O. meyeriana's strong resistance to Xoo and find new disease resistance candidate genes.