Statement of Removal

Rice yield is directly influenced by spikelet number, a trait governed by both genetic and hormonal regulatory pathways. In this study, we demonstrate that <i>GNA</i>, a <i>GRAS</i> family transcription factor, acts as a key positive regulator of spikelet development in rice. Through map-based cloning, transgenic manipulation, and molecular assays, we show that <i>GNA</i> enhances grain number per panicle by repressing <i>OsCKX2</i>, a cytokinin oxidase gene responsible for cytokinin degradation. Chromatin immunoprecipitation, luciferase activity assays, and electrophoretic mobility shift assays (EMSA) confirm that <i>GNA</i> directly binds to the <i>OsCKX2</i> promoter, suppressing its transcription and thereby elevating endogenous cytokinin levels. Notably, <i>GNA</i> physically interacts with <i>DEP1/dep1</i>, and this interaction further enhances the <i>GNA</i>-mediated repression of <i>OsCKX2</i>. Overexpression of <i>GNA</i> significantly increases spikelet number, pedicel branching, and grain yield per plant, accompanied by the activation of cytokinin-responsive genes. These findings reveal a previously uncharacterized <i>DEP1-GNA-OsCKX2</i> regulatory module that links G-protein signaling with cytokinin signaling and panicle morphogenesis, providing a promising genetic target for rice yield improvement and molecular breeding.