连锁与连锁不平衡联合作图解析烟草青枯病抗性遗传变异

Dissection of Genetic Variations for Tobacco Bacterial Wilt Resistance Based on Joint Linkage and Linkage Disequilibrium Mapping

选用“粤烟98”ד118-3”构建的133份F7代单粒传重组自交系(RIL)群体和94份烟草种质组成的自然群体作为研究材料,运用253个SSR和293个InDel标记对这些材料进行基因分型,并针对烟草青枯病抗性开展连锁和连锁不平衡联合作图分析。结果显示,基于RIL群体的连锁分析在4个环境中共发现4个解释率介于12.00%~30.10%之间的QTLs,利用自然群体的关联分析在3个环境中发现解释率在8.78%~11.42%之间的8个单倍型与抗病性密切相关,利用RIL群体和自然群体开展的连锁-连锁不平衡的整合作图分析发现8个解释率介于4.95%~6.93%之间的单倍型与抗病性密切相关。两种或以上分析方法均探测到与烟草青枯病抗性密切相关的单倍型有4个,分别为具正表型效应的Hap227和Hap368及负表型效应的Hap289和Hap370。所得结果表明连锁和连锁不平衡联合作图策略能较准确地发现与烟草青枯病抗性相关的QTLs,该结果可为烟草青枯病抗性相关研究及后续烟草青枯病抗性材料的辅助筛选提供参考。

A population with 133 F7 recombinant inbred lines(RIL)derived from the cross of“Yueyan 98”ד118-3”and a natural population with 94 tobacco accessions were used as materials,and joint linkage and linkage disequilibrium(LD)mapping analysis for tobacco bacterial wilt(TBW)resistance was carried out by using 253 SSR and 293 InDel markers.Four QTLs with 12%-30.10%of the explanation rate were detected by linkage analysis of the RIL population in four environments;and 8 haplotypes were found to be closely related to TBW resistance in three environments and explained 8.78%-11.42%of phenotypic variation by LD mapping with natural population.The integrated linkage-LD mapping of the RIL and natural populations was carried out and 8 haplotypes were detected to be closely associated with TBW resistance and explained 4.95%-6.93%of phenotypic variation.Four haplotypes were found to be associated with TBW resistance in at least two of the three analytical methods,two(Hap227 and Hap370)of them are with positive phenotypic effect,and the other two(Hap289,Hap368)are with negative effect.The results indicate that the strategy of joint linkage-LD mapping could accurately detect QTLs related to TBW resistance,and these haplotypes could provide reference for TBW resistance research and screening of TBW resistance materials.