Mechanism and Breeding Application of Bacterial Blight Gene in Rice

Abstract

Rice is one of the most important food crops in the world. Rice disease is a major threat to its yield loss. Bacterial blight caused by the gram-negative bacterium Xanthomonas oryzae pv. oryzae (Xoo), is one of the three major diseases that seriously affect rice yield. The traditional chemical control methods have many drawbacks. The cultivation and planting of rice varieties resistant to bacterial blight is recognized worldwide as the most safe and effective means to control the disease. Identification of resistant germplasm resources and discovery of resistant genes are the premise of resistant varieties breeding. Under the pressure of both natural and artificial selections, new pathogenic varieties have emerged one after another due to the constant variation of bacterial blight pathogens, and the main varieties have gradually lost their disease resistance. Therefore, it is necessary to explore and identify more durable disease resistance genes. In the study, 16 bacterial blight resistance genes that have been cloned are briefly classified, and then three genes Xa23, Xa7 and xa5 that are broad-spectrum resistant to bacterial blight with good application are described in detail from the aspects of gene discovery, location, cloning, mechanism of action, and etc. The conventional breeding, molecular marker-assisted selection breeding, transgenic breeding and gene marker breeding for bacterial blight resistance are introduced. In addition, the prospect of molecular breeding for broad-spectrum resistance to bacterial blight is put forward based on the characteristics of different bacterial blight genes and the problems in current breeding and utilization.

Keywords

• rice
• bacterial blight
• xa23
• xa7
• xa5
• breeding application