Transcriptional control of local auxin distribution by the CsDFB1-CsPHB module regulates floral organogenesis in cucumber
Jing Nie, Nan Shan, Huan Liu, Xuehui Yao, Ziwei Wang, Ruoxue Bai, Yicong Guo, Ying Duan, Changlin Wang, Xiaolei Sui
Abstract
Significance Auxin is a key phytohormone influencing multiple aspects of plant development, including meristem maintenance, primordia initiation, floral organogenesis, and vascular differentiation. Local auxin biosynthesis and polar auxin transport are essential to establish and maintain auxin gradients that ensure proper plant development. Here, we demonstrate that CsDFB1, a member of the plant cystatin superfamily, which was previously implicated in defense responses, plays a critical role in regulating local auxin distribution and thus influences floral organogenesis in cucumber. Genetic and biochemical assays suggest that CsDFB1 affects local auxin distribution by acting as an attenuator that interacts with CsPHB and modulates CsPHB-mediated transcriptional control of CsYUC2 and CsPIN1 . Our results shed light on the fine tuning of local auxin distribution in plants.