Tac4controls Tiller Angle By Regulating The Endogenous Auxin Content And Distribution In Rice

Tiller angle, an important component of plant architecture, greatly influences the grain yield of rice (Oryza sativaL.). Here, we identifiedTiller Angle Control 4(TAC4) as a novel regulator of rice tiller angle.TAC4encodes a plant-specific, highly conserved nuclear protein. The loss ofTAC4function leads to a significant increase in the tiller angle.TAC4can regulate rice shoot gravitropism by increasing the indole acetic acid content and affecting the auxin distribution. A sequence analysis revealed thatTAC4has undergone a bottleneck and become fixed inindicacultivars during domestication and improvement. Our findings facilitate an increased understanding of the regulatory mechanisms of tiller angle and also provide a potential gene resource for the improvement of rice plant architecture.