小麦纹枯病抗性QTL分析

Analysis of QTLs for the Resistance to Sharp Eyespot in Wheat

小麦纹枯病是世界性的小麦重要病害之一,培育和使用抗病品种是减轻纹枯病危害最经济和有效的手段。为了挖掘更多的小麦纹枯病抗性QTL用于小麦标记辅助育种,本研究构建了CI12633和扬麦158重组自交系群体,采用二代测序方法开发SNP分子标记,并对群体中的94个家系进行基因型分析,构建遗传连锁图;采用牙签接种和病麦粒接种的方法鉴定重组自交系群体纹枯病抗性,进而对小麦纹枯病抗性QTL进行定位。结果显示,构建的遗传连锁图包含3355个分子标记,遗传距离为2510.66 cM,共有31个连锁群,均能分配到相应的染色体;在5A(2)、6A、1B、2B、3B、4B、5B、6B(2)、7B、1D、2D(2)、4D和7D染色体共发现16个与小麦纹枯病抗性相关的QTL,单个QTL可解释9.0%~26.8%的表型变异;除了7B染色体的QTL来源于感病品种扬麦158,其余QTL均来自抗病品种CI12633;3B、7D和5A(Chr5A_564101963)染色体的QTL与已有报道一致,其余均为新发现的QTL。发现的QTL和紧密连锁分子标记为今后小麦抗纹枯病分子标记辅助育种以及抗纹枯病基因的克隆提供帮助。

Wheat sharp eyespot(WSE)is an important disease worldwide.It is an economic and effective measure to develop and apply the cultivars with disease resistance.In order to explore more QTLs resistant to WSE for marker-assisted breeding,the recombinant inbred lines(RILs)were constructed by crossing CI12633 and Yangmai 158.SNP markers were developed by second-generation sequencing method,and the genotypes of RILs were analyzed to construct genetic linkage map.Combined with the resistance evaluation data of WSE by toothpick inoculation and disease grain inoculation,the QTLs of resistance to WSE were mapped.The results showed that there were 31 linkage groups in the genetic linkage map,containing 3355 molecular markers with a genetic distance of 2510.66 cM,all of which could be allocated to the corresponding chromosomes based on SSR markers.On chromosomes 5A(2),6A,1B,2B,3B,4B,5B,6B(2),7B,1D,2D(2),4D and 7D,16 QTLs were found for WSE resistance.The QTL of 7B chromosome was contributed by Yangmai 158,while the other QTLs were all from the resistant variety of CI12633.The QTLs on chromosomes 3B,7D and 5A(Chr5A_564101963)were consistent with the reported ones,while the rest were newly discovered QTLs.The QTLs and the tightly linked molecular markers will be helpful for marker-assisted breeding and cloning of resistance genes in the future.