Modulates Plant Architecture through Regulating GA and Indole-3-Acetic Acid Metabolism.

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 (), there are 12 , but the role of the miR396- regulatory module remains unknown. Here, we report that shapes plant architecture via the regulation of auxin and GA metabolism in rice. is mainly expressed in lamina joints, nodes, internodes, axillary buds, and young inflorescences. Overexpression of 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 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 gene and , which are involved in the GA synthesis and auxin signaling pathways, respectively. Correspondingly, alters the contents of endogenous GAs and auxins and sensitivity to exogenous phytohormones. These findings establish as a crucial component in the OsmiR396--plant hormone regulatory network that controls rice plant architecture.