OsGRF11 regulates cell division and elongation by interacting with GF14e and affecting gibberellin signaling

Abstract GROWTH-REGULATING FACTORs (GRFs) are plant-specific transcription factors that play critical roles in plant growth and development. In this study, we used CRISPR/Cas9 genome editing technology to knock out nine members of the rice (Oryza sativa) GRF gene family. Among these, mutation in OsGRF11 resulted in the most pronounced semi-dwarf phenotype, characterized by reduced cell length and number. Further analysis revealed that OsGRF11 mutation reduced rice sensitivity to exogenous gibberellin (GA). Co-immunoprecipitation-mass spectrometry (IP-MS) assays confirmed a physical interaction between OsGRF11 and GF14e, a 14-3-3 family protein, in which loss-of-function mutations caused dwarf phenotypes. Further experiments showed that the OsGRF11–GF14e complex interacts with key GA signaling components: DELLA protein SLENDER RICE1 (SLR1) and F-box protein GIBBERELLIN-INSENSITIVE DWARF2 (GID2). Specifically, OsGRF11, GF14e, and SLR1 showed pairwise interactions, and GID2 interacted directly with GF14e. Notably, GID2 was located within the first intron of GF14e, and the two genes showed coordinated spatial expression. When OsGRF11 was mutated, expression levels of cell expansion, cyclin, and cellulose synthesis genes were significantly downregulated, and certain GA-inducible genes failed to be induced by exogenous GA. These results suggest that OsGRF11 may regulate stem length by forming protein complexes with proteins involved in GA signaling.