QTL Mapping of Leaf Length and Width in Brassica campestris L.
DENG Jie，WANG Hui，CHENG Feng，WU Jian，WANG Xiao-wu*
Institute of Vegetables and Flowers，Chinese Academy of Agricultural Sciences，Key Open Lab of Vegetable Genetics and Bio-physics，China-Netherland Joint Horticulture Crop Genome Technology Lab，Beijing 100081，China
摘要 利用2套白菜类作物双单倍体（DH）群体与分别包含230、143个分子标记的遗传图谱，运用复合区间作图法对叶长、叶宽、叶片形态指数（叶宽/叶长）3个叶片形态学性状进行QTL定位及遗传效应分析。结果表明：两个DH群体中，在6个连锁群上共检测到9个QTLs位点，其中6个QTLs与叶长相关，2个QTLs与叶片形态指数相关，1个QTL与叶宽相关。这些QTLs分别位于连锁群A01、A03、A05、A06、A09和A10上。各位点的遗传贡献率介于7.1%～28.1%之间。其中，叶长与叶片形态指数的QTLs在两个群体中定位于同一染色体上相近的位置。通过亲本重测序数据对Z16_SZQ F1 DH群体进行标记加密，最终将叶片形态指数QTL定位于标记BrID111431位点处，对该位点白菜注释基因分析发现在距BrID111431标记54 Kb处存在可能的候选基因BrXTH9。95份白菜类作物构成的自然群体转录组数据表明该基因的表达量与叶片形态指数存在极显著相关性，BrXTH9可能在白菜类作物中参与了叶片形态指数的调控。
Abstract：The aim of this study was to map and analyze QTLs controlling leaf traits in Brassica campestris L.，so as to provide information for molecular marker assisted selection（MAS）of breeding．QTL analysis was conducted for leaf width，leaf length，and leaf index in 2 Brassica campestris L. DH populations．The results showed that 9 QTLs located on 6 linkage groups were detected，including 6 QTLs for leaf length，2 QTLs for leaf index，and 1 QTL for leaf width．These 9 QTLs explained 7.1%-28.1% morphological variations of the 2 populations．QTL analysis indicated that the QTLs controlling leaf length and leaf index were located on adjacent positions in the 2 DH populations．According to genome re-sequencing data of parents，more markers were mapped in the QTL region of leaf index on A03 in the Z16_SZQ F1 DH population．Further analysis showed that the QTL controlling leaf index trait was located on the BrID111431 locus．One candidate gene，e. g. BrXTH9，was found by analysis with annotated genes between A. Thaliana and Brassica campestris L. which was 54 Kb physical distance from BrID111431．The transcript me analysis of natural population showed that BrXTH9 was highly correlated with leaf index，indicating that BrXTH9 may involve in regulation of leaf index in Brassica campestris L.
