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Rice blast, caused by filamentous ascomycete Magnaporthe oryzae, is one of the most destructive diseases of rice worldwide.Genetic resistance is considered to be the most economic, effective and environmentally responsible method for its control.However, resistance genes (R genes) typically lose their effectiveness after a short period in commercial production, due to the emergence of compatible races of M.oryzae virulent to R genes.Therefore, it is necessary to mine new blast R genes with broadspectrum resistance from diverse genetic resources or pyramid R genes with different resistance spectra into a single elite cultivar in order to achieve durable resistance to this disease.Exploration of new resistance genes to improve resistance to blast from diverse genetic resources is the inevitable choice for breeders.The genus Oryza consists of twenty-one wild and two cultivated species.O.sativa, the Asian cultivated rice is grown all over the world;The African cultivated rice, O.glaberrima is only grown in West Africa, and being replaced everywhere by the Asian species.Among 80 known blast R genes conferring resistance to different races of M.oryzae, most of them are identified from Asian cultivated rice (O.sativa), with the exception of Pi 9, Pi 33 and Pi 40 genes identified from O.minuta, O.rufipogon and O.australiensis, respectively.