History of near-isogenic lines carrying genes for resistance to bacterial blight and blast in rice (Oryza sativa L.).

Bacterial blight and blast, caused by Xanthomonas oryzae pv. oryzae and Magnaporthe oryzae, respectively, are the two most devastating diseases of rice (Oryza sativa L.). Although the diseases were first documented in the 17th-19th centuries, systematic research on their pathology and host resistance began in the early 20th century and was significantly accelerated following the development of near-isogenic lines (NILs) carrying single resistance genes in universally susceptible backgrounds in the 1980s. Sets of NILs for bacterial blight (IRBB) and International Rice Research Institute (IRRI)-bred Blast-resistant Line (IRBL) were developed through a long-term collaboration between the IRRI and the Japan International Research Center for Agricultural Sciences. Over the years, these materials have been widely distributed for pathogen population monitoring, studying the molecular mechanisms of resistance, assessing the synergistic effect of multiple resistance genes, and developing new resistant varieties, thereby benefiting millions of rice farmers worldwide. In this article, we describe the historical development of the IRBB and IRBL lines, highlight their global impact, and provide perspectives on their relevance not only for bacterial blight and blast but also for emerging rice diseases that could benefit from this approach.