[Advances of rice bacterial blight disease resistance gene Xa21]

Gene Xa21 is the first disease resistance gene cloned from rice (Oryza sativa L.), which encodes a receptor-like kinase and confers broad spectrum resistance against Xanthomonas oryzae pv. oryzae (Xoo). In this paper, the discovery, mapping and cloning of Xa21 were reviewed briefly. The molecular mechanism of resistance and its breeding application, including biochemical properties of the kinase domain of XA21, AvrXa21 identification, the disease resistance pathway mediated by Xa21, and the mechanism of disease resistance were summarized. Future perspective on Xa21-related research is also discussed.