title: Identification of the novel recessive gene pi55(t) conferring resistance to Magnaporthe oryzae.
abstract: 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-metal-associated domain-containing protein, respectively, were suggested as the most likely candidates for pi55(t).
authors.affiliation: State Key Laboratory of Conservation and Utilization of Subtropical Agro-bioresources, Laboratory of Plant Resistance and Genetics, College of Natural Resources and Environment Sciences, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Xiuying
authors.initials: X
authors.lastname: He
authors.forename: Xinqiong
authors.initials: X
authors.lastname: Liu
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Ling
authors.initials: L
authors.lastname: Wang
authors.forename: Fei
authors.initials: F
authors.lastname: Lin
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Cheng
authors.forename: Zhaoming
authors.initials: Z
authors.lastname: Chen
authors.forename: Yaoping
authors.initials: Y
authors.lastname: Liao
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Pan
mesh_terms: D002874:Chromosome Mapping / Q000379:methods; D032461:Chromosomes, Plant / Q000235:genetics; D003433:Crosses, Genetic; D060467:Disease Resistance / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics*; D005808:Genes, Recessive / Q000235:genetics; D018745:Genome, Plant / Q000235:genetics; D054884:Host-Pathogen Interactions; D020082:Magnaporthe / Q000254:growth & development* / Q000502:physiology; D012275:Oryza / Q000235:genetics* / Q000382:microbiology; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology