《自然》（Nature)杂志3月24日在线发表了有关小麦A基因组测序的研究论文。该研究首次完成了小麦A基因组的测序和草图绘制，对未来深入和系统研究麦类植物结构与功能基因组学，以及进一步推动栽培小麦的遗传改良具有重要意义。这项研究由中科院遗传与发育生物学研究所植物细胞与染色体工程国家重点实验室小麦研究团队发起，通过与深圳华大基因研究院和美国加州大学戴维斯分校合作完成。
小麦是全球最重要的粮食作物。广泛种植的普通小麦是一个异源六倍体，含有A、B和D三个基因组。追本溯源，普通小麦是由祖先野生的一粒小麦（乌拉尔图小麦，含AA基因组）与拟斯卑尔托山羊草杂交形成四倍体小麦。大约在8000年前，四倍体小麦与粗山羊草再一次自然杂交，经自然和人类的选择形成如今广泛栽培的普通小麦。由于普通小麦基因组大而复杂（是水稻基因组的40倍），85%以上序列为重复序列，致使基因组测序研究进展缓慢。
研究团队利用新一代测序技术，对二倍体乌拉尔图小麦G1812系的基因组进行测序、组装、注释及相关分析。鉴定出34,879个编码蛋白基因，与已知禾本科作物基因组比较分析，鉴定出3,425个A基因组特异基因和24个新小RNA，并发现含NB-ARC功能域的抗病基因在小麦A基因组明显增多。通过同源基因的比对和关联分析，还鉴定出一批控制重要农艺性状的基因。此外，该研究还筛选出大量遗传分子标记，将有助于重要数量农艺形状基因的克隆及基因组选择，促进小麦的分子育种。
有关专家指出，这项成果将为研究小麦驯化史提供一个全新的视角，并为多倍体小麦基因组的测序分析提供二倍体基因组参照序列。注释出的基因信息和分子标记有助于加速小麦的遗传改良，对保障粮食安全和农业可持续发展具有重要作用。(生物谷Bioon.com)
doi:10.1038/nature11997
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Draft genome of the wheat A-genome progenitor Triticum urartu
Hong-Qing Ling, Shancen Zhao, Dongcheng Liu,Junyi Wang, Hua Sun, Chi Zhang, Huajie Fan, Dong Li, Lingli Dong, Yong Tao, Chuan Gao, Huilan Wu, Yiwen Li, Yan Cui, Xiaosen Guo, Shusong Zheng, Biao Wang, Kang Yu, Qinsi Liang, Wenlong Yang, Xueyuan Lou, Jie Chen, Mingji Feng, Jianbo Jian, Xiaofei Zhang, Guangbin Luo, Ying Jiang, Junjie Liu, Zhaobao Wang, Yuhui Sha, Bairu Zhang, Huajun Wu, Dingzhong Tang, Qianhua Shen, Pengya Xue, Shenhao Zou, Xiujie Wang, Xin Liu, Famin Wang, Yanping Yang, Xueli An, Zhenying Dong, Kunpu Zhang, Xiangqi Zhang, Ming-Cheng Luo, Jan Dvorak, Yiping Tong, Jian Wang, Huanming Yang, Zhensheng Li, Daowen Wang, Aimin Zhang & Jun Wang, Show fewer authors.
Bread wheat (Triticum aestivum, AABBDD) is one of the most widely cultivated and consumed food crops in the world. However, the complex polyploid nature of its genome makes genetic and functional analyses extremely challenging. The A?genome, as a basic genome of bread wheat and other polyploid wheats, for example, T. turgidum (AABB), T. timopheevii (AAGG) and T. zhukovskyi (AAGGAmAm), is central to wheat evolution, domestication and genetic improvement1. The progenitor species of the A?genome is the diploid wild einkorn wheat T.?urartu2, which resembles cultivated wheat more extensively than do Aegilops speltoides (the ancestor of the B genome3) and Ae. tauschii (the donor of the D genome4), especially in the morphology and development of spike and seed. Here we present the generation, assembly and analysis of a whole-genome shotgun draft sequence of the T.?urartu genome. We identified protein-coding gene models, performed genome structure analyses and assessed its utility for analysing agronomically important genes and for developing molecular markers. Our T.?urartu genome assembly provides a diploid reference for analysis of polyploid wheat genomes and is a valuable resource for the genetic improvement of wheat.
