野生植物的驯化为人类定居与文明起源奠定了重要基础。在世界范围内不同地区生活的古人类分别对当地不同的野生植物进行了驯化, 而经过驯化的作物常常表现出相似的驯化综合性状。在基因组层面上对趋同选择规律的解析, 可为作物育种提供重要信息与遗传资源。近日, 中国农业大学杨小红/李建生和华中农业大学严建兵领衔的团队从单基因和全基因组2个层次系统解析了玉米(Zea mays)和水稻(Oryza sativa)趋同选择的遗传基础, 发现玉米KRN2与水稻OsKRN2受到了趋同选择, 并通过相似的途径调控玉米与水稻的粒数与产量。他们还发现玉米与水稻在全基因组范围内存在大量趋同选择同源基因对(gene pair), 这些基因在淀粉代谢、糖及辅酶合成等途径特异富集。该研究不仅克隆了在玉米与水稻中均具有重要育种价值的趋同选择同源基因对KRN2/OsKRN2, 而且在全基因组水平上揭示了玉米与水稻趋同选择的规律, 为进一步解析驯化综合性状形成的分子机理及其在育种中的应用奠定了重要理论基础。

Domestication of wild plants was crucial for human settlement and the development of civilization, which arose independently in many different geographic areas on different wild species. However, these crops underwent variant domestication process displaying the ‘domestication syndrome’ with a common suite of traits. The systematical analysis of convergent selection at genome level may provide important information and genetic resources for crop breeding. Recently, a team led by Xiaohong Yang and Jiansheng Li from Chinese Agricultural University and Jianbing Yan from Huazhong Agricultural University reported the genetic basis of convergent selection between maize and rice at both single gene and whole genome levels. Particularly, they found the maize KRN2 and rice OsKRN2 genes experienced convergent selection and regulated grain number and yield in a similar pathway. Moreover, they identified a large number of orthologous gene pairs that underwent convergent selection during maize and rice evolution, which were enriched in certain pathways including starch metabolism, sugar and coenzyme synthesis. This significant work not only cloned KRN2/OsKRN2 orthologous gene pairs with great value in maize and rice breeding, but also revealed the convergent selection between maize and rice at the genome level, providing critical foundations for studying the molecular basis of domestication syndrome and their applications in breeding practices.