Identification Of Rice Blast Resistance Gene And Monitoring Of Avirulence Gene On Magnaporthe Grisea

provinces. In order to prevent and control the occurrence of rice blast in the Jilin province, it is very important identify resistance genes of rice blast and monitor the physiological race of the fungus.In this research, 100 rice varieties of Jilin province was identified resistance to 22 Magnaporthe grisea strains. 98% of rice varieties can be infected by Magnaporthe grisea. The result showed that the Jijing 801, fengyuan18 had a significantly higher rice blast resistance than ZuPei 11, the Hai 132.According to NCBI GenBank database and related articles of 6 resistance gene sequences, Pi-b, Pi-ta, Pi-9, Pid-2, Pi-36 and Pi-kh were cloned by PCR from 98 rice varieties and found that the distribution frequency of Pi-9 gene was 21.4%, Pi-36 was 86.7%, Pi-b gene was 25.5%, Pid-2 gene was 92.9%, Pi-kh gene was 98%, Pi-ta gene was 94.9%. We found that Pi-9 and Pi-b were broad spectrum resistance gene, were obviously missed in Jilin province. Maybe this can explain why the rice in Jilin Province was subject to so serious rice blast in recent years. It will be more helpful to know the resistance genotypes to rice blast for protect rice from Magnaporthe grisea. According to five avirulence gene sequences, five specific primers (PWL2, AVR-CO39, ACE1, AVR-Pib, AVR-Pita) were designed. The result showed that all the Magnaporthe grisea have AVR-Pib gene, AVR-CO39 was 68.30%, PWL-2 was 95.40%, ACE1 was 98.40%.The use of AVR-Pita primers for genomic DNA amplification, 2kb PCR products appeared in three strains, accounting for the total number of test strain 2.4%; 52 strains were found 1.5kb PCR products; 26 strains were found 1.3kb PCR products , accounting for 20.6% of the total number of strains; 45 strains with no amplification, accounting for 35.7% total strain. All the different types of PCR products based on restriction analysis, randomly selected the same PCR products strains, cloning avirulence gene and sequencing analysis. Clear the main mechanism of avirulence gene variation.AVR-Pita and Pita in line with the'gene for gene'relations. Identification of the rice blast resistance gene Pita distribution through the PCR method and found that the gene frequency was about 94.9%; however, Identification of the rice blast fungus Avirulence Gene AVR-Pita and found only three strains of the amplified fragment was normal, while the remaining 123 strains of the corresponding gene were mutation or deletion. This variation break the resistance gene and avirulence gene one-to-one relationship between genes, leading to Magnaporthe grisea on rice contains genes Pita can also be susceptible to Magnaporthe grisea. In recent years with frequent large-scale outbreak of rice blast fungus, only identified that rice blast resistance genes and avirulence genes of rice blast fungus distribution by molecular methods, would be able to prevent and treat the rice blast.