Resistance Genes of Oryza sativa for Protection Against Xanthomonas oryzae pv. oryzae, the Causative Agent of Bacterial Leaf Blight

Abstract

Rice (Oryza sativa) is a major staple crop around the world, particularly in developing regions such as Africa and Asia.  Attack of the rice crop by pathogens has the capacity to greatly diminish crop yield with major agricultural, economical and human consequences.  Xanthomonas orzyza pv. oryzae (Xoo), the causative agent of bacterial leaf blight, has the ability to cause substantial crop loss, up to 80% worldwide.  Genetic sources of resistance have long been considered the most sustainable method of disease control, both from an environmental and agricultural perspective.  This review considers the discovery, evolution, characterization and utilization of resistance genes (R genes) in rice against Xoo. R genes for Xoo are plentiful and exist at multiple loci throughout the rice genome due to multiple gene duplication and transposition events.  The presence of multiple gene loci makes gene pyramiding and resistance stacking accessible and fruitful applications in breeding for resistance.  Biotechnological approaches to take advantage of R gene function have also begun to take root.  However, a more global and concerted effort to study the multiple varieties and climates in which rice is grown is required in order to truly attain food security and find sustainable resistance.