The State Key Laboratory of Plant Cell and Chromosome Engineering, and Center for Genome Editing, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Plant J. 2018 Jun;94(5):857-866. doi: 10.1111/tpj.13903. Epub 2018 Apr 24.
GW2 is emerging as a key genetic determinant of grain weight in cereal crops; it has three homoeologs (TaGW2-A1, -B1 and -D1) in hexaploid common wheat (Triticum aestivum L.). Here, by analyzing the gene editing mutants that lack one (B1 or D1), two (B1 and D1) or all three (A1, B1 and D1) homoeologs of TaGW2, several insights are gained into the functions of TaGW2-B1 and -D1 in common wheat grain traits. First, both TaGW2-B1 and -D1 affect thousand-grain weight (TGW) by influencing grain width and length, but the effect conferred by TaGW2-B1 is stronger than that of TaGW2-D1. Second, there exists functional interaction between TaGW2 homoeologs because the TGW increase shown by a double mutant (lacking B1 and D1) was substantially larger than that of their single mutants. Third, both TaGW2-B1 and -D1 modulate cell number and length in the outer pericarp of developing grains, with TaGW2-B1 being more potent. Finally, TaGW2 homoeologs also affect grain protein content as this parameter was generally increased in the mutants, especially in the lines lacking two or three homoeologs. Consistent with this finding, two wheat end-use quality-related parameters, flour protein content and gluten strength, were considerably elevated in the mutants. Collectively, our data shed light on functional difference between and additive interaction of TaGW2 homoeologs in the genetic control of grain weight and protein content traits in common wheat, which may accelerate further research on this important gene and its application in wheat improvement.
GW2 正在成为谷物作物粒重的一个关键遗传决定因素；它在六倍体普通小麦（Triticum aestivum L.）中有三个同源基因（TaGW2-A1、-B1 和 -D1）。在这里，通过分析缺乏一个（B1 或 D1）、两个（B1 和 D1）或三个（A1、B1 和 D1）同源基因的 TaGW2 基因编辑突变体，我们对 TaGW2-B1 和 -D1 在普通小麦粒型性状中的功能有了一些了解。首先，TaGW2-B1 和 -D1 都通过影响粒宽和粒长来影响千粒重（TGW），但 TaGW2-B1 的影响更强。其次，TaGW2 同源基因之间存在功能相互作用，因为双突变体（缺乏 B1 和 D1）的 TGW 增加量明显大于其单突变体。第三，TaGW2-B1 和 -D1 都调节发育籽粒外果皮的细胞数量和长度，TaGW2-B1 的作用更强。最后，TaGW2 同源基因也影响粒蛋白含量，因为该参数在突变体中普遍增加，特别是在缺乏两个或三个同源基因的系中。与这一发现一致的是，两个与小麦用途质量相关的参数，面粉蛋白含量和面筋强度，在突变体中显著升高。总的来说，我们的数据揭示了 TaGW2 同源基因在普通小麦粒重和蛋白含量性状遗传控制中的功能差异和累加作用，这可能加速对这个重要基因的进一步研究及其在小麦改良中的应用。
