2019•Nature CommunicationsOpen access
Whole-genome resequencing reveals Brassica napus origin and genetic loci involved in its improvement
Kun Lu, Lijuan Wei, Xiaolong Li, Yuntong Wang, Jian Wu, Miao Liu, Chao Zhang, Zhiyou Chen, Zhongchun Xiao, Hongju Jian, Feng Cheng, Kai Zhang, Hai Yan Du, Xin-Chao Cheng, Cun-Ming Qu, Wei Qian, Liezhao Liu, Rui Wang, Qingyuan Zou, Jiamin Ying, Xingfu Xu, Jiaqing Mei, Ying Liang, Yourong Chai, Zhanglin Tang, Huafang Wan, Yu Ni, Yajun He, Na Lin, Yonghai Fan, Wei Sun, Nannan Li, Gang Zhou, Hongkun Zheng, Xiaowu Wang, Andrew H. Paterson, Jiana Li
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Abstract
Brassica napus (2n = 4x = 38, AACC) is an important allopolyploid crop derived from interspecific crosses between Brassica rapa (2n = 2x = 20, AA) and Brassica oleracea (2n = 2x = 18, CC). However, no truly wild B. napus populations are known; its origin and improvement processes remain unclear. Here, we resequence 588 B. napus accessions. We uncover that the A subgenome may evolve from the ancestor of European turnip and the C subgenome may evolve from the common ancestor of kohlrabi, cauliflower, broccoli, and Chinese kale. Additionally, winter oilseed may be the original form of B. napus. Subgenome-specific selection of defense-response genes has contributed to environmental adaptation after formation of the species, whereas asymmetrical subgenomic selection has led to ecotype change. By integrating genome-wide association studies, selection signals, and transcriptome analyses, we identify genes associated with improved stress tolerance, oil content, seed quality, and ecotype improvement. They are candidates for further functional characterization and genetic improvement of B. napus.
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