云南省稻瘟病菌群体对稻瘟病抗性单基因系的致病性分析

Pathogenicity Analysis of Magnaporthe oryzae Populations of Yunnan on Monogenic Lines for Resistance to Rice Blast

稻瘟病是水稻生产最具毁灭性的病害之一,抗病品种的利用是控制该病最经济、有效和环保的措施。明确稻瘟病抗性基因的抗性水平,可有效指导抗病育种的开展。本研究利用24个以丽江新团黑谷为背景的稻瘟病抗性单基因系,对2007年至2010年采集自云南籼稻和粳稻区共379个稻瘟病菌株进行了致病性测定。结果表明,Pi9和Pi5可在籼稻和粳稻区使用;Pik-h、Pita-2、Piz-5、Pita和Piz基因只能在籼稻区使用;Piz-t和Pi20基因仅能在粳稻区使用。对2个基因的联合致病性系数、联合毒性系数和抗性互补系数分析表明,Pik/Pi7、Piz/Pi9和Pi1/Pikm等3对基因的组合可作为籼稻区的有效抗源组合;而Pi1/Pik-h、Pi5/Pi9和Pi9/Pi20等3对基因的组合可作为粳稻区的有效抗源组合。群体致病性分析表明,绝大部分的抗性基因在云南已经失效,需发掘新的抗源用于抗病育种。

Rice blast caused by Magnaporthe oryzae was one of the most destructive disease of rice worldwide,and the most economic,effective and environment-friendly measure was to use resistant cultivars.Understanding the resistant spectrum of known genes to blast disease in rice-growing regions could facilitate the selection of effective resistance genes in disease-resistant breeding programs.In present study,virulence of 379 M.oryzae isolates collected from Indica and Japonica rice-growing regions of Yunnan were tested on 24 monogenic lines with the genetic background of Lijiangxingtuanheigu（Oryza sativa L.ssp.Japonica）.The results showed that Pi9 and Pi5 genes could be used as resistant donors in both Indica and Japonica-growing region;and Pik-h,Pita-2,Piz-5,Pita and Piz genes could be rationally deployed in Indica-growing region;Piz-t and Pi20 could only be used in Japonica-growing region. According to the analysis of pahtogenicity association coefficient,virulence association coefficient and resistance complementarity coefficient,the combinations of two genes available in Indica-growing region were Pik/Pi7,Piz/Pi9 and Pi1/Pikm; and Pi1/Pik-h,Pi5/Pi9 and Pi9/Pi20 could be used in Japonica-growing region.Based on the date of virulence analysis of M.oryzae population collected from Yunnan,the most of the known genes lost their resistance against M.oryzae in Yunnan,thus,there was an urgent need to identify novel blast resistance genes from rice genetic resources for disease-resistant breeding programs.