Li Yingjie, Huang Ke, Zhang Limin, Zhang Baolan, Duan Penggen, Zhang Guozheng, Huang Xiahe, Zhou Chen, Han Nannan, Zheng Leiying, Wang Yingchun, Li Yunhai
State Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, 100039, China.
Nat Commun. 2025 Apr 26;16(1):3944. doi: 10.1038/s41467-025-59236-w.
Grain size is a key agronomic traits that influence grain yield in crops. The transcription factor GS2/OsGRF4 can improve grain size and yield, but its underlying mechanism remains unclear. Here we report a suppressor of the gain-of-function allele GS2 (SUG1) that encodes a plant-specific protein DEP2/SRS1/EP2/OsRELA and acts as a transcriptional regulator. The sug1 mutants form short grains, while overexpression of SUG1 results in long grains. GS2 directly activates the expression of SUG1. SUG1 associates with transcription factors OsBZR1, OsMADS56 and OsSPL13 to control grain size through GA and BR signaling as well as growth pathways. Natural variation in SUG1 contributes to grain size diversity, and the SUG1 allele from indica varieties can be used to improve grain size and yield of japonica varieties with the SUG1 allele. Thus, our findings uncover that the GS2-SUG1 module controls grain size by integrating multiple growth signals, providing the potential targets for crop improvement.
籽粒大小是影响作物产量的关键农艺性状。转录因子GS2/OsGRF4能够提高籽粒大小和产量，但其潜在机制仍不清楚。在此，我们报道了功能获得性等位基因GS2的一个抑制因子（SUG1），它编码一种植物特异性蛋白DEP2/SRS1/EP2/OsRELA，并作为转录调节因子发挥作用。sug1突变体形成短粒种子，而SUG1过表达则导致长粒种子。GS2直接激活SUG1的表达。SUG1与转录因子OsBZR1、OsMADS56和OsSPL13相互作用，通过赤霉素（GA）和油菜素内酯（BR）信号传导以及生长途径来控制籽粒大小。SUG1的自然变异导致了籽粒大小的多样性，籼稻品种的SUG1等位基因可用于改良携带该等位基因的粳稻品种的籽粒大小和产量。因此，我们的研究结果揭示了GS2-SUG1模块通过整合多种生长信号来控制籽粒大小，为作物改良提供了潜在靶点。
