Plant-specific GROWTH-REGULATING FACTORs (GRFs) participate in central developmental processes, including leaf and root development; inflorescence, flower, and seed formation; senescence; and tolerance to stresses. In rice (Oryza sativa), there are 12 GRFs, but the role of the miR396-OsGRF7 regulatory module remains unknown. Here, we report that OsGRF7 shapes plant architecture via the regulation of auxin and GA metabolism in rice. OsGRF7 is mainly expressed in lamina joints, nodes, internodes, axillary buds, and young inflorescences. Overexpression of OsGRF7 causes a semidwarf and compact plant architecture with an increased culm wall thickness and narrowed leaf angles mediated by shortened cell length, altered cell arrangement, and increased parenchymal cell layers in the culm and adaxial side of the lamina joints. Knockout and knockdown lines of OsGRF7 exhibit contrasting phenotypes with severe degradation of parenchymal cells in the culm and lamina joints at maturity. Further analysis indicated that OsGRF7 binds the ACRGDA motif in the promoters of a cytochrome P450 gene and AUXIN RESPONSE FACTOR12, which are involved in the GA synthesis and auxin signaling pathways, respectively. Correspondingly, OsGRF7 alters the contents of endogenous GAs and auxins and sensitivity to exogenous phytohormones. These findings establish OsGRF7 as a crucial component in the OsmiR396-OsGRF-plant hormone regulatory network that controls rice plant architecture.

植物特异性生长调节因子 (GRF) 参与中央发育过程，包括叶和根发育；花序、花和种子的形成；衰老; 和对压力的耐受力。水稻 ( Oryza sativa ) 中有 12 个GRF ，但 miR396- OsGRF7调节模块的作用仍不清楚。在此，我们报告OsGRF7通过调节水稻中的生长素和 GA 代谢来塑造植物结构。OsGRF7主要表达于叶片节、节、节间、腋芽和幼花序。OsGRF7的过度表达导致半矮化和紧凑的植物结构，茎壁厚度增加，叶角变窄，这是由细胞长度缩短、细胞排列改变以及茎和叶片接头的近轴侧实质细胞层增加介导的。OsGRF7的敲除和敲低品系表现出截然不同的表型，成熟时秆和叶片接头中的实质细胞严重退化。进一步分析表明，OsGRF7 结合细胞色素 P450基因和AUXIN RESPONSE FACTOR12启动子中的 ACRGDA 基序，分别参与 GA 合成和生长素信号通路。相应地，OsGRF7改变内源 GA 和生长素的含量以及对外源植物激素的敏感性。这些发现证实OsGRF7是控制水稻植株结构的 OsmiR396- OsGRF-植物激素调控网络的重要组成部分。