一个粳稻来源抗稻瘟病基因的鉴定、遗传分析和基因定位

7001S是一个广谱抗稻瘟病的粳稻两用核不育系,对来自全国不同稻区的22株稻瘟病菌系均表现为高度抗性。通过构建7001S/80-4B F2群体的遗传分析和初步定位表明,F2分离单株对稻瘟病菌的抗性呈明显的抗、感双峰分布,抗感分离符合3﹕1的理论比例,说明粳稻7001S对稻瘟病菌的抗性由1对显性核基因或一个显性QTL位点控制,并将该基因初步定位于第11染色体长臂末端。进一步通过扩大遗传群体和分子标记开发,利用基于BSA的隐性群体分析技术,将目的基因精细定位于P21-2415和RM27322之间约310 kb的范围内,并获得了可用于分子标记辅助选择的紧密连锁和共分离分子标记,同时对目标基因所在区域进行基因预测,初步确定了候选基因。为进一步开展该抗稻瘟病基因的克隆、功能验证和抗病机理研究,以及通过分子标记辅助选择技术培育抗稻瘟病水稻新品种等工作奠定了基础。

Identification,Genetic Analysis and Gene Mapping of a Rice Blast Resistance Gene in Japonica Rice

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. 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 0.27 cM and physical distance of310 kb. Some co-segregated molecular markers were also found in this gene area and could be used for identifying candidate genes.