水稻白叶枯病抗性遗传解析

Genetic dissection of rice resistance to bacterial blight

摘要:

水稻白叶枯病是水稻主要的病害之一，对水稻生产具有重要的意义。本研究以国外引进粳稻品种Maybelle与地方籼稻品种白叶秋为亲本构建而成的加倍单倍体(doubled haploid, DH)群体为材料，调查了4个白叶枯病致病小种的致病性。结果表明，各小种的致病性在DH群体间呈现连续分布，并伴有一定的超亲变异。而且，各个致病小种的致病性具有一定的相关性，相关系数处在0.3与0.6之间。数量性状位点(quantitative trait locus, QTL)分析共检测到12个QTL，分别位于水稻第1、2、3、5、6、7、9和12号染色体，贡献率介于4.95%-16.05%之间，其中位于5号染色体上的RM6024-RM163区间在3个致病小种中均检测到，并且是效应最大的主效QTL。另外，QTL座位的聚合进一步表明，通过不同的QTL座位的聚合能够显著提高水稻白叶枯病的抗性。该研究对拓宽我国白叶枯病抗性基因资源具有重要的意义。

关键词:白叶枯病;数量性状位点(QTL);水稻;基因聚合

Abstract:

Bacterial blight, a major disease in rice, poses a serious impact on rice production. In this study, a doubled haploid (DH) population derived from a cross between the introduced japonica cultivar ‘Maybelle’ and the indica landrace ‘Baiyeqiu’ was used to investigate the pathogenicity of four pathogen races causing bacterial blight. The results showed that the pathogenicity of all the pathogen races exhibited continuous, transgressive distribution in the DH population. Moreover, strong correlations existed between every two pathogen races, with the correlation coefficients ranging from 0.3 to 0.6. A total of 12 quantitative trait loci (QTLs) distributed on chromosomes 1, 2, 3, 5, 6, 7, 9, and 12 were detected for rice bacterial blight, explaining 4.95% to 16.05% of the phenotype. Among these QTLs, a major QTL located in the interval RM6024-RM163 on chromosome 5 was detected in three pathogen races. In addition, the pyramiding of the positive alleles can apparently improve the rice resistance to bacterial blight. This study is of great significance for broadening the genetic resources with resistance to bacterial blight in China.

Key words:bacterial blight;quantitative trait locus (QTL);rice(Oryza sativa L.);gene pyramiding