甘蓝型油菜株高、第一分枝高和分枝数的QTL检测及候选基因筛选

株高、分枝数及第1分枝高是油菜重要的农艺性状。本研究利用甘蓝型油菜GH06和P174杂交,F2通过单粒法连续自交至F11构建重组自交系群体,利用油菜60K芯片对该群体进行基因分型,构建高密度遗传连锁图谱。结果表明,该图谱包含2795个SNP多态性标记位点,总长1832.9 c M,相邻标记间平均距离为0.66 c M。在此图谱基础上采用复合区间作图法(CIM),检测到3个农艺性状的24个QTL。其中11个株高QTL分别位于A01、A06、A07、A08、A10和C06染色体,单个QTL解释5.00%~15.26%的表型变异;7个第1分枝高QTL分别位于A06、C05和C06染色体,单个QTL解释5.04%~12.99%的表型变异;6个分枝数QTL分别位于A03、A07、C01、C04和C06染色体,单个QTL解释5.95%~8.14%的表型变异。将156个拟南芥株高相关基因、10个拟南芥第1分枝高相关基因和148个拟南芥分枝数相关基因与QTL对应置信区间序列进行同源比较分析(E1E–20),分别找出了20个株高候选基因、3个第1分枝高候选基因以及12个分枝数候选基因。2个环境中在A07染色体上重复检测到的QTL置信区间检测到与株高相关的候选基因ATGID1B/GID1B和WRI1,A08染色体上重复检测到的QTL置信区间检测到SLR/IAA14和AXR2/IAA72个与株高相关的候选基因。在具有部分置信区间重叠的q2013FBH-C05-1和q2014FBH-C05-2区间均检测到第1分枝高候选基因PHT1;8,在A03和C06染色体上的QTL置信区间内,分别检测到4个分枝数候选基因,匹配E值介于0~3E–56之间。

Quantitative Trait Loci Mapping for Plant Height,the First Branch Height,and Branch Number and Possible Candidate Genes Screening in Brassica napus L.

Plant height, the first branch height and branch number are important agronomic traits in rapeseed. In our study, QTL mapping of plant height, the first branch height and branch number in Brassica napus was tested by using the high density SNP genetic map constructed from the high generation RIL population with the rapeseed 60K chip array. The reference SNP genetic map contains 2795 SNP markers, covering 1832.9 cM with an average distance of 0.66 cM in B. napus genome. Totally, 24 putative QTLs were identified for plant height, the first branch height and branch number by using the complex interval mapping. The phenotypic variation was explained by individual QTL ranged from 5.00% to 15.26% for 11 QTLs of plant height, from 5.04% to 12.99% for seven QTLs of the first branch height, and from 5.95% to 8.14% for six QTLs of branch number. We collected 156 genes associated with plant height, 10 genes associated with the first branch height and 148 genes associated with branch number in Arabidopsis thaliana and searched the homology region of the QTL confidence interval E-value<1E–20 to screen the possible candidate genes. We found 20 genes associated with plant height, three genes associated with the first branch height and 12 genes associated with branch number. The plant height candidate genes ATGID1B/GID1B and WRI1 were found in QTL confidence interval on A07 and SLR/IAA14 and AXR2/IAA7 were found in QTL confidence interval on A08 in 2013 and 2014. The first branch height candidate gene PHT1;8 was found in QTLs q2013FBH-C05-1 and q2014FBH-C05-2 that had an overlapping confidence interval. Moreover, we found four genes associated with branch number that E-value from 0 to 3E–56 on A03 and C06, respectively.