A DOF transcription factor GLW9/OsDOF25 regulates grain shape and tiller angle in rice

Abstract

Grain shape and tiller angle are two important agronomic traits influencing grain yield and quality in rice. Herein, we map-based cloned a grain shape gene GLW9 (Grain Length and Width on chromosome 9), which encodes a DNA binding with one finger (DOF) family transcription factor OsDOF25. GLW9 positively regulates grain length and negatively regulates grain width, consequently improving grain length-to-width ratio and appearance quality. GLW9 binds to the EXPA6 promotor to upregulate its expression, thereby positively regulating cell expansion and grain shape. On the other hand, GLW9 directly upregulates the expression of OsPIN1b to reduce tiller angle. This study elucidates the mechanism by which GLW9 coordinately regulates grain shape and tiller angle, providing theoretical reference and gene resources for the improvement of grain shape and tiller angle in rice.