Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics, Beijing, China.
State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Weigang, Nanjing, China.
Nat Genet. 2016 Oct;48(10):1218-24. doi: 10.1038/ng.3634. Epub 2016 Aug 15.
Brassica species, including crops such as cabbage, turnip and oilseed, display enormous phenotypic variation. Brassica genomes have all undergone a whole-genome triplication (WGT) event with unknown effects on phenotype diversification. We resequenced 199 Brassica rapa and 119 Brassica oleracea accessions representing various morphotypes and identified signals of selection at the mesohexaploid subgenome level. For cabbage morphotypes with their typical leaf-heading trait, we identified four subgenome loci that show signs of parallel selection among subgenomes within B. rapa, as well as four such loci within B. oleracea. Fifteen subgenome loci are under selection and are shared by these two species. We also detected strong subgenome parallel selection linked to the domestication of the tuberous morphotypes, turnip (B. rapa) and kohlrabi (B. oleracea). Overall, we demonstrated that the mesohexaploidization of the two Brassica genomes contributed to their diversification into heading and tuber-forming morphotypes through convergent subgenome parallel selection of paralogous genes.
芸薹属物种包括白菜、萝卜和油菜等作物，表现出巨大的表型变异。芸薹属基因组都经历了全基因组三倍化（WGT）事件，但其对表型多样化的影响尚不清楚。我们对 199 份芸薹属白菜和 119 份芸薹属甘蓝进行了重测序，这些样本代表了各种形态类型，并在中间六倍体亚基因组水平上鉴定到了选择信号。对于具有典型叶球特征的白菜形态类型，我们在白菜亚基因组内鉴定到了四个显示出亚基因组间平行选择的亚基因组位点，在甘蓝亚基因组内也鉴定到了四个这样的位点。有 15 个亚基因组位点受到选择，并且这两个物种都有这些位点。我们还检测到了与块茎形态类型（萝卜，芸薹属白菜）和球茎甘蓝（甘蓝，芸薹属甘蓝）驯化相关的强烈的亚基因组平行选择。总的来说，我们证明了这两个芸薹属基因组的中间六倍体化通过同源基因的亚基因组平行选择，导致了它们向有叶球和形成块茎的形态类型的多样化。
