摘要
The elite rice cultivar Yuejingsimiao 2 （YJ2） is characterized by a high level of grain quality and yield, and resistance against Magnaporthe oryzae. YJ2 showed 100% resistance to four fungal populations collected from Guangdong, Sichuan, Liaoning, and Heilongjiang Provinces, which is a higher frequency than that shown by the well-known resistance （R） gene donor culti- vats such as Sanhuangzhan 2 and 28zhan. Segregation analysis for resistance with F2 and F4 populations indicated the re- sistance of YJ2 was controlled by multiple genes that are dominant or recessive. The putative R genes of YJ2 were roughly tagged by SSR markers, located on chromosomes 2, 6, 8, and 12, in a hulked-segregant analysis using genome-wide selected SSR markers with F4 lines that segregated into 3 resistant （R）： 1 susceptible （S） or 1R：3S. The recessive R gene on chromosome 8 was further mapped to an interval ~1.9 cM/152 kb in length by linkage analysis with genomic position-ready markers in the mapping population derived from an F4 line that segregated into 1R：3S. Given that no major R gene was mapped to this inter- val, the novel R gene was designated as pi55（t）. Out of 26 candidate genes predicted in the region based on the reference genomic sequence of the cultivar Nipponbare, two genes that encode a leucine-rich repeat-containing protein and heavy-metalassociated domain-containing protein, respectively, were suggested as the most likely candidates for pi55（t）.
The elite rice cultivar Yuejingsimiao 2 (YJ2) is characterized by a high level of grain quality and yield, and resistance against Magnaporthe oryzae. YJ2 showed 100% resistance to four fungal populations collected from Guangdong, Sichuan, Liaoning, and Heilongjiang Provinces, which is a higher frequency than that shown by the well-known resistance (R) gene donor cultivars such as Sanhuangzhan 2 and 28zhan. Segregation analysis for resistance with F 2 and F 4 populations indicated the resistance of YJ2 was controlled by multiple genes that are dominant or recessive. The putative R genes of YJ2 were roughly tagged by SSR markers, located on chromosomes 2, 6, 8, and 12, in a bulked-segregant analysis using genome-wide selected SSR markers with F 4 lines that segregated into 3 resistant (R):1 susceptible (S) or 1R:3S. The recessive R gene on chromosome 8 was further mapped to an interval 1.9 cM/152 kb in length by linkage analysis with genomic position-ready markers in the mapping population derived from an F 4 line that segregated into 1R:3S. Given that no major R gene was mapped to this interval, the novel R gene was designated as pi55(t). Out of 26 candidate genes predicted in the region based on the reference genomic sequence of the cultivar Nipponbare, two genes that encode a leucine-rich repeat-containing protein and heavy-metalassociated domain-containing protein, respectively, were suggested as the most likely candidates for pi55(t).
基金
supported by the National Natural Science Foundation of China (Grant No. U1131003)
the National Transgenic Research Projects(Grant Nos. 2009ZX08009-023 and 2011ZX08001-002)
the Guangdong Provincial Natural Science Foundation (Grant No. 10151064001000008)
the President Science Foundation of Guangdong Academy of Agricultural Sciences (Grant No. 201101)
