Researchers Analyze the Function of TaGW2 Genes in Wheat Grain Traits

The GW2 gene is emerging as a key determinant of grain weight in cereal crops. In hexaploid wheat (Triticum aestivum), it has three homoeologs, TaGW2-A1, -B1, and -D1. The team of Yi Zhang from the Chinese Academy of Sciences analyzed the CRISPR-edited mutants that lack one, two, or all three homoeologs of TaGW2 to gain insights into the functions of TaGW2 in wheat grain traits.

Both TaGW2-B1 and -D1 affect the thousand-grain weight (TGW) by influencing grain width and length, but the effect conferred by TaGW2-B1 is stronger than that of TaGW2-D1. There is also a functional interaction between the TaGW2 homoeologs since the TGW increase shown by a double mutant (lacking B1 and D1) was substantially larger than that of their single mutants.

TaGW2-B1 and -D1 were also found to modulate cell number and length in the outer pericarp of developing grains, with TaGW2-B1 being the more potent one. TaGW2 homoeologs also affect grain protein content as this was generally increased in all mutants, especially in the double and triple mutants. Moreover, flour protein content and gluten strength were also elevated in the mutants.

These data provide insights on the functions of the TaGW2 homoeologs in the genetic control of grain weight and protein content traits in common wheat. This may accelerate research on this important gene and its application in wheat improvement.

For more information, read the article in The Plant Journal.