Cloning Of A Blast Resistance Gene In Japonica Two-line Male Sterile Line 7001S And Function Verification

Rice blast caused by Magnaporthe grisea is a worldwide rice disease. Its incidence area and harmful levels is the first of the three major diseases of rice, causing serious losses to China and the world rice production each year. Use of resistant cultivars is the most economical, effective and safe among ways of prevention. However, resistant varieties with a single resistance gene will reduce or even completely lose blast resistance and spectrum with the evolution of pathogens and the advantage of physiological changes during long-term cultivation. Therefore, it is crucial to identify and exploit resistance resources, and to isolate and clone resistance genes. Utilizing these new resistance genes to breed new resistant varieties becomes the eternal project of modern rice blast resistance breeding.7001S is a male-sterile rice with broad-spectrum resistance to rice blast pathogens and highly resistant to 22 strains of Magnaporthe oryzae (M. oryzae). The F2 generation of hybrid between 7001S and 80-4B showed significant resistance to rice blast pathogens. The ratio of resistant plants:susceptible plants was 3:1, indicating that the resistance of 7001S to the rice blast is controlled by one-dominant karyogene or a QTL locus. Conclusion follows:1. Molecular marker analysis showed that the rice blast resistance gene was located on the terminal long arm of chromosome 11 between P21-2415 and RM27322, with genetic distance of 0.13 cM and physical distance of 310 kb. Some co-segregated molecular markers were also found in this gene area and could be used for identifying candidate genes.2. Construct a high-resolution map and an electronieally physical map spanning the target region of the target gene.3. Through identification of candidate gene markers as well as sequencing of candidate genes, which are LOC_Os11g45980, LOC_Os11g46200 and LOC_Os11g46210.4. Candidate gene LOC_Os11g45980 encoded NB-ARC disease resistance protein. Candidate gene LOC_Os11g46200 encoding LRR resistance protein structure shows that it contains an ATP kinase binding sites and a leucine-rich repeat sequences domain. LOC_Os11g46200 also encods LRR resistance protein.5. Interference vector was successfully constructed a candidate gene overexpression vector and complementary expression vectors.7001S is acceptor material of interference vector, and LTH is the material of overexpression and complementary. Transgenic plants were made a positive identification at the molecular level, and positive rate is higher.6. Transgenic plants of 7001S showed susceptibility. Expression of the target gene interference in transgenic plants is decreased by quantitative PCR.Transgenic plants of overexpression and complementarity had gained. Field and molecular of resistance identification are appraisaling. The foundation was laid for rice breeding of disease resistance.