Abstract: Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of bacterial blight disease in rice. The Xoo-Rice interaction is consistent with the "gene-for-gene" hypothesis and is an ideal model system for understanding mechanisms of molecular plant-pathogen interactions. In the last decade, important pathogenicity-related genes of Xoo had been cloned and identified. Genomic bioinformatics of other gram-negative plant bacterial pathogens, including other Xanthomonas species, has facilitated research on molecular pathogenicity determinants of Xoo, especially on mining TTSS (type III secretion system) effectors. A brief review on the current knowledge of the molecular mechanisms of Xoo pathogenicity is made in order to provide a basis for functional genomics of molecular rice-Xoo interactions.

Key words: Rice, Xanthomonas oryzae pv. oryzae, Pathogenicity determinant, Hypersensitive response, Type III secretion system