甘蓝型油菜RIL群体株高性状的全基因组关联分析

Genome-wide association study of plant height in rapeseed RIL population

为提高甘蓝型油菜株高的分子标记辅助育种效率,挖掘与株高相关的功能基因以构建理想株型,利用单个重组自交系（RIL）群体在3个环境下的株高表型数据及7 877个SNP标记的基因型分型数据进行全基因组关联分析。在2个或2个以上环境下同时检测到5个与株高显著相关的SNP（Bn-scaff_15794_3-p62430、Bn-A02-p9599263、Bn-A02-p9409799、Bn-A02-p9993945和Bn-A02-p9636219）,均位于A02染色体上。比较利用连锁分析方法的QTL定位结果,发现标记Bn-A02-p9599263和Bn-scaff_15794_3-p62430分别位于QTL（q PH2-2和q PH2-4）峰值处,标记Bn-A02-p9636219和Bn-A02-p9993945分别落在QTL（q PH2-3和q PH2-4）2-LOD的置信区间内,标记Bn-A02-p9409799距离QTL（q PH2-2）的置信区间0.3c M。利用关联分析定位的区间（69.5~80.7c M）比利用连锁方法定位的QTL区间（60.7~95.9c M）缩小了24c M。依据参考基因组信息,在标记Bn-scaff_15794_3-p62430附近2kb处找到1个与株高性状相关的候选基因（GSBRNA2T00090973001）。结果表明,单个RIL群体进行全基因组关联分析可以对连锁QTL分析结果进行补充,缩小QTL置信区间。

To increase the efficiency of molecular marker-assisted selection on plant height and ideotype,data from 3 environments were collected using recombination inbred lines（RILs） population of Brassica napus,and genotypic data from 7 877 SNPs were investigated for genome-wide association. 5 significant SNPs（Bn-scaff_15794_3-p62430,Bn-A02-p9599263,Bn-A02-p9409799,Bn-A02-p9993945 and Bn-A02-p9636219）for plant height had been identified in at least 2 environments. They were located on A02 chromosome. Compared to QTL linkage analysis,the markers（Bn-A02-p9599263 and Bn-scaff_15794_3-p62430） respectively located on the peak of QTL q PH2-2 and q PH2-4. Markers Bn-A02-p9636219 and Bn-A02-p9993945 were located in 2-LOD（log of the likehood odds ration） confidence interval for QTLs q PH2-3 and q PH2-4. Bn-A02-p9409799 was found near distance of 0. 3 cM confidence interval QTL（q PH2-2）. The interval range of QTL by genome-wide association studies（69. 5-80. 7 cM） was 24 c M shorter than that by QTL linkage analysis（60. 7-95. 9cM）. According to the reference genome annotation information,a candidate gene（GSBRNA2T00-090973001） corresponding to the significant SNP（Bn-scaff_15794_3-p62430） was predicted,locating in 2 kb away from the SNP. These results indicated that using single RIL population for gene-wide association studies not only compensated QTL＇s linkage results,but also provided theoretical basis for fine mapping and gene cloning.