Fine Mapping Of A Blast Resistance Gene Pi47in Rice Cultivar Xiangzi3150

Rice blast is one of the most important rice diseases caused by fungal pathogen Magnaporthe oryzae and lead to a significant reduction of output. Development and use of resistant cultivar is a safe, economical and environmental friendly approach to overcome the problem caused by the rice blast other than chemical control methods,Fine mapping and cloning of these resistance genes will be the material and technique basis for breeding new resistant cultivar. The experimental material in this study, Xiangzi3150, a local rice cultivar from Hunan province, has been proved to perform broad-spectrum and durable resistance to rice blast isolates after years of practice. Analysis of both F2population and recombinant inbred line(RIL) population derived from the cross between the highly susceptible cultivar CO39and Xiangzi3150indicated that two major R genes Pi47and Pi48which locate on chromosome11and12respectively were responsible for its resistance. The objective of this study is to fine map the Pi47,which is useful for the map-based cloning of Pi47in future. The main results consist of four points:1. Based on inoculation with blast isolate193-1-1and Pi47linkage marker assisted selection,12monogenic lines which only contain Pi47but not Pi48were selected from the F10RIL population and backcrossed with CO39respectively.2. Three populations derived from crosses of the above monogenic lines and CO39were chosen for fine mapping based on the segregation ratio of3:1after inoculating with blast isolate193-1-1.1687susceptible individuals were identified from these three populations and used for fine mapping. The mapping data show that Pi47was located in the interval between SSR marker RM224and STS marker K134.3. By using new developed molecular markers, the Pi47was further mapped between the CAPS markers S32and K33with genetic distances0.21cM and0.03cM respectively.4. The P147monogenic lines and other four near-isogenic lines respectively contained Pik, Pikm, Pikh and Pikp were used in the resistance spectrum screening. The results showed that the Pi47gene was different from other four R genes.