稻瘟病抗性基因Pita^2的克隆及其介导的防御相关基因表达分析

Cloning of the rice blast resistance gene Pita^2 and expression analysis of defence related genes mediated by Pita^2

为了克隆位于水稻12号染色体着丝粒区域具有广谱抗性的稻瘟病抗性基因Pita^2,研究构建并筛选了该基因供体品种PiNo.4的Fosmid文库,构建Pita^2候选区域的物理图谱并互补验证了5个候选基因,克隆得到了稻瘟病抗性基因Pita^2,确认了该基因就是Ptr基因.一组基因型接近、对Pita^2致病性相反的稻瘟病菌菌株对水稻进行离体接种,接种前后相关防御基因的表达量分析结果表明,Pita^2基因在稻瘟病菌侵染后均成功激活了水杨酸和茉莉酸抗病信号通路,主要通过参与水稻水杨酸信号通路赋予水稻抗性,该研究为利用Pita^2培育持久广谱抗性水稻提供了一定的理论基础.

In order to clone the broad-spectrum rice blast resistance gene Pita^2 with broad-spectrum resistance located in the centromere region of rice chromosome 12,the Fosmid library of Pita^2 donor cultivar PiNo.4 was constructed and screened,then the physical map of the candidate region of Pita^2 was constructed.Rice blast resistance gene Pita^2 which was cloned by complementation of five candidate genes,was confirmed to be Ptr gene.Furthermore,a group of strains with similar genotype and opposite pathogenicity to Pita^2 were selected to analyze the expression changes of defence related genes mediated by Pita^2.Quantitative PCR results showed that Pita^2 confered resistance to rice mainly by participating in the salicylic acid signaling pathway,although the salicylic acid and jasmonic acid signaling pathways were both activated.The research provides a certain theoretical basis to breed durable broad-spectrum resistant rice cultivars utilizing rice blast resistance gene Pita^2.