Overexpression of TaCR4-A positively regulates grain size in Triticum aestivum

Grain size is a critical factor that affects yield in wheat (Triticum aestivum). CRINKLY4 (CR4) receptor-like kinase regulates epidermal cell differentiation and seed development in several plant species, yet its functional role in wheat remains to be clarified.

In this study, we identified the TaCR4 gene, which encodes the CRINKLY4 receptor-like kinase homolog in wheat. We created overexpressing (OE) wheat lines with increased TaCR4-A expression and found that the grain length, width, thickness, and weight of the OE lines increased. Cytological analysis revealed that the overexpression of TaCR4-A increased the length, width, and area of wheat grain outer pericarp cells.

This study demonstrated that TaCR4 positively regulates wheat grain size by regulating the size of grain epidermal cells.