Mapping of the Resistant Gene to Rice Blast in the Dual Purpose Genic Male Sterile Rice, LongS

Abstract

LongS is a dual purpose genic male sterile rice with broad-spectrum resistance to rice blast. The objective of the present study was to identify the resistance spectrum to rice blast, to analyze the genetic behavior of resistance gene, and to map the major resistance genes in LongS. LongS had a resistance frequency of 100% inoculated with 41 strains of Magnaporthe oryzae. Population genetic analysis showed that the resistance genes in LongS exhibited dominant inheritance, the genetic model of R gene varied depend on the strains of Magnaporthe oryzae. The main-effect resistant gene to rice blast was fine mapped, by using the bulk segregant analysis (BSA) and recessive class analysis (RCA) methods, with the F2 population derived from the resistant parent of LongS and the susceptible parent of Nipponbare. A single resistant gene to the race of 318-2 located on the interval flanked by the SSR markers of M1 and M2 with a genetic distance of 1.3 cM on chromosome 9 were adjacent to the broad-spectrum blast resistance gene, Pi5. Both of the resistance spectrum and resistant frequency of LongS, however, were significantly different to those of resistant gene of Pi5 and Pii. In conclusion, the major-effect resistant gene identified in this study may be a new broad-spectrum blast resistance gene. The DNA markers linked to the new R gene identified in this study should be useful for marker-aided breeding of blast-resistant rice cultivars.