Genetic Diversity Of Magnaporthe Grisea From Rice In Jiangsu And Identification Of Resistance Rice Blast Gene

Rice blast caused by Magnaporthe grisea is the most important disease in the rice production and seriously influenced the yield and cause serious economic losses. The current selection and use of resistant varieties is still the most cost-effective method to control disease. Because of pathogenic differentiation of M.grisea resistance of rice vatieties with high resistance is easily overcome in 3-5 years. Therefore, the pathogenicity of M. grisea Variation and population genetic structure for in-depth understanding of their biological characteristics, disease resistance breeding guide on the use of resistant varieties or production of disease prevention and treatment layout have great significance.Pot2-rep-PCR technique was used to analyze the diversity of M. grisea from Jiangsu in 2007 and 2008. They were divided 14 lineages and JSL5 was dominant. The results showed that the rice blast fungus are rich in diversity in Jiangsu, but when compared with the group structure of 1999-2002, it tended to be more simple; By analyzing temporal and spatial distribution of M. grisea, we found that Population structure of M. grisea varied significantly between years and diferent rice cultivation areas of Jiangsu, but there were some M. grisea have the same fingergroup.Based on the Pot2-rep-PCR fingerprinting research into the 199 M.grisea isolates ampled from Jiangsu five rice growing areas between 2007and 2008, we analyzed the solates taking advantage of the encoding program established by Yijunzhou in 2000. The result turned out that rich polymorphism existed in the tested isolates for the two consecutive years. Significant differences were found for the tested isolates in terms of encoding programs as compared to the result obtained by Juanbai (2003).174 M.grisea isolates ware collected from rice in Jiangsu in 2007-2008, Pathpgenicity were studied with 3 sets of differentials. The results indicated that the Chinese race differentials, the Tsunematru mono-resistance-gene lines from Japan and the LTH-NILs could differentiate the 44 isolates into 10,41 and 13 pathogenic types respectively, Fl and G1 was also dominant among china-races. Comared to 67 reaction types in 2000 about Japan-race, it significantly reduced, As a whole, the blast pathogen population structure tended to be more simple. In this paper, we analyzed the genetic diversity of Magnaporthe grisea sampled from the same ecological system in Ganyu county, Jiangsu province. The results suggested that the number of code formula from a single variety was obviously less than that of the surrounding ones, moreover. M.grisea isolates under different conditions, however, shared the same dominant lineage and code formula by taking on more close origination relationship. While in the present study, significant differences were still found in the types of code formula across all the varieties.337 rice varieties were identified by Using 22 standard strains about resistance genes. Preliminary results revealed that the incidence frequency of Pik,Pia were 62.65% and 60.84%, respectively, while the frequency of Pi9,Pita2,Pikm,Pikh more then 5%. the incidence frequency of the four genes and other resistance genes was also low at the same time, they could be developed and in future research, and also could be considered to make use of in Japonica rice areas.