Affiliation:
1. State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, National Center for Soybean Improvement, College of Agriculture Nanjing Agricultural University Nanjing 210095 China
2. Institute of Crop Science, College of Agriculture and Biotechnology Zhejiang University Hangzhou 310058 China
Abstract
ABSTRACTLight is one of the most essential environmental factors that tightly and precisely control various physiological and developmental processes in plants. B‐box CONTAINING PROTEINs (BBXs) play central roles in the regulation of light‐dependent development. In this study, we report that BBX9 is a positive regulator of light signaling. BBX9 interacts with the red light photoreceptor PHYTOCHROME B (phyB) and transcription factors PHYTOCHROME‐INTERACTING FACTORs (PIFs). phyB promotes the stabilization of BBX9 in light, while BBX9 inhibits the transcriptional activation activity of PIFs. In turn, PIFs directly bind to the promoter of BBX9 to repress its transcription. On the other hand, BBX9 associates with the positive regulator of light signaling, BBX21, and enhances its biochemical activity. BBX21 associates with the promoter regions of BBX9 and transcriptionally up‐regulates its expression. Collectively, this study unveiled that BBX9 forms a negative feedback loop with PIFs and a positive one with BBX21 to ensure that plants adapt to fluctuating light conditions.
Funder
National Natural Science Foundation of China