【摘要】 <正>由真菌Magnaporthe grisea引起的稻瘟病是我国水稻三大病害之一,也是遍及世界各水稻产区的重要病害,每年均有不同程度的发生,流行年份一般减产10%-20%,严重的达40%-50%,局部田块甚至颗粒无收。稻瘟病菌在进化过程中形成了遗传更多还原

【Abstract】 Rice blast,caused by fungus Magnaporthe grisea,is one of the most serious dis- eases of rice throughout the world and is also a classical system in which avirulence(AVR)genes in the pathogen show a functional correspondence with particular resistance(R)genes in rice.The interaction between A VR-pita gene in Magnaporthe grsiea and Pi-ta gene in rice is a classical gene-for-gene system.The genetic diversity of A VR-pita alleles was showed by 44 isolates from the fields in Sichuan and Chongqing.According to the published sequence of A VR-pita(GenBank Accession No.AF207841),the special primers were designed and a population analysis of A VR- pita occurrence in the field was conducted.The PCR negative isolates did not trigger host resis- tance responses and the disease might occur.The positive special PCR band in an isolate was not corresponding with its avirulence to the Pi-ta rice line.Among 11 sequenced A VR-pita alleles,six A VR-pita alleles encoded the same protein,four proteins differed from each other by one amino acid and one had nonsense mutation.The strategy of utilizing Pi-ta in rice breeding was also dis- cussed.更多还原