抗病基因Pi-ta和Ptr的共进化特征及其显性功能分子标记开发

Co-evolutionary Characteristics and Development of the Codominant Markers of the Resistance Genes Pi-ta and Ptr

稻瘟病是威胁水稻产区最严重的病害之一,选择合适的抗病基因培育抗病品种是控制稻瘟病最经济有效的措施。已克隆的两个重要抗稻瘟病基因,Pi-ta和Ptr,不仅共同定位在水稻第12号染色体着丝粒附近,而且两者的抗病功能密切相关。本研究通过对Pi-ta基因染色体区段的微共线性分析,发现该区段在稻属染色体多倍化及重塑进程中进化模式非常保守。其次,针对Pi-ta和Ptr基因序列变异位点,设计了新的显性功能性分子标记,根据PCR产物电泳条带的有无,即可快速鉴定水稻品种中Pi-ta和Ptr的抗感病基因型。应用此标记对18份江苏省近年来主栽水稻品种进行鉴定,结果表明Pi-ta和Ptr抗病等位基因在供试品种中共存在频率较高(14/18),且在水稻个体中表现稳定,可有效预防多种稻瘟病菌的侵染,应继续加强基因监测,以防丢失。本研究有助于解析水稻及其近缘物种的抗病机制以及提高抗病品种选育效率,对防治稻瘟病菌侵害和保证水稻产量及安全具有一定的现实意义。

Rice blast is one of the most serious diseases in rice.Using resistance genes to breed resistance varieties is the most economical and effective measure to control rice blast.The cloned two important rice blast resistance genes,Pi-ta and Ptr,are not only co-localized near the centromere of chromosome 12,but also have closely related resistant function.In this study,the microcollinearity analysis showed the evolutionary pattern of Pi-ta gene chromosome segment was much conserved in the process of chromosome polyploidy and remodeling in Oryza.Secondly,a new dominant functional molecular marker was designed for the Pi-ta and Ptr resistance alleles,respectively.According to the presence or absence of electrophoretic bands of the PCR products,the resistance and susceptibility alleles of Pi-ta and Ptr in rice varieties can be quickly identified.This marker was used to identify 18main rice cultivars in Jiangsu Province in recent years.The results showed that the Pi-ta and Ptr resistance alleles co-existed at a high frequency(14/18)in the tested cultivars,and were stably expressed in rice individuals.Though most of the test cultivars can effectively prevent the infection of a variety of rice blast fungus,it still should contin ue to strengthen genetic monitoring to prevent the loss of resistant genes.This study will help to analyze the disease resistance mechanism of rice and its related species and improve the breeding efficiency of disease-resistant varieties,it also has practical significance for preventing and controlling rice blast and ensuring rice yield and safety.