Blast, caused by the fungal pathogen Pyricularia grisea, is the most devastating disease of rice worldwide. Knowledge of the pathotype composition of the pathogen in rice fields is essential for rational deployment of resistance genes in rice breeding programs. In this study, we assayed the pathotypes of the pathogen populations using samples recently collected from 13 major rice-growing provinces of central and southern China. In all, 792 single spore isolates were tested for pathogenicity reactions using 13 host differentials consisting of six indica and seven japonica near-isogenic lines (NILs). The compositions of the pathogen populations were complex; 48 pathotypes were identified with the indica NILs, 82 pathotypes were detected with the japonica NILs, and a total of 344 pathotypes were identified with both indica and japonica NILs. There were large differences in distribution of the pathotypes among the different rice-growing areas. Even neighbor provinces seemed to differ sharply in types and frequencies of the most prevalent pathotypes. There was also a large difference in the frequencies of the isolates producing compatible reactions on the NILs, indicating the difference in frequencies of avirulence genes in the pathogen populations. The data provided very useful information for formulating strategies for improving blast resistance in rice breeding programs.
由稻瘟病菌引起的水稻稻瘟病是全球范圍內影響水稻生產最具破壞性的疾病。了解稻瘟病病原體的致病型組成能協(xié)助在水稻抗病育種過程中加入對應的抗性基因。本研究中，我們近期從中國中部和南部的13個主要水稻種植省份收集了樣本，并對病原種群的致病型進行分析?？偣?92單孢菌株進行了測試，使用13個鑒定寄主包括6個秈稻和7個粳稻近等基因系進行致病型反應。發(fā)現(xiàn)病原種群的組成十分復雜; 秈稻近等基因系鑒定出48個稻瘟病菌致病型，粳稻近等基因系中檢測到82個致病類型，秈稻和粳稻近等基因系共鑒定出344個致病型。不同稻區(qū)的稻瘟病菌致病型的分布差異很大，甚至相鄰省份的稻瘟病菌的類型和最常見致病型的發(fā)生頻率也明顯不同。同時，近等基因系上出現(xiàn)兼容反應的菌株的頻率的不同，表明病原群體中無毒基因的出現(xiàn)頻率存在差異。這些數(shù)據(jù)為抗稻瘟病水稻品種的培育提供了非常有用的信息。