An OsGLK1/2-DGP1/2/3 feedback module regulates rice photosynthesis and yield.

Abstract

GOLDEN2-LIKE (GLK) proteins are central regulators of plant photosynthesis, and their molecular mechanisms are not fully elucidated, especially in rice. Here, we report a GLK-centered molecular module that regulates rice photosynthesis and yield. <i>Osglk1 Osglk2</i> double mutants are seedling lethal, and <i>Osglk2</i> presents faded leaves and white panicles, which indicated the partially redundant role of <i>OsGLK1</i> and <i>OsGLK2</i> in photosynthesis regulation. Transcriptome sequencing analysis indicated that OsGLK regulates the expression of genes related to carbohydrate metabolism and photosynthesis. Overexpression of <i>OsGLK1</i>/<i>2</i> results in dark-green-panicle phenotypes. We proved that DEEP GREEN PANICLE2 (DGP2) and DGP3, homologs of DGP1, are direct repressors of OsGLK activity and function negatively in rice chlorophyll content regulation. Moreover, OsGLK directly binds to the promoters of <i>DGP1</i>/<i>2</i>/<i>3</i> and activates their expressions. Agronomic trait analysis showed that mutations of <i>DGP1</i> and <i>DGP2</i> significantly increased seed weight and yield of rice. Together, these results manifested an OsGLK1/2-DGP1/2/3 feedback module regulating rice photosynthesis and yield and may provide approaches for crop breeding.