Phytochrome B inhibits the activity of phytochrome-interacting factor 7 involving phase separation
Yu Xie,
Wenbo Liu,
Wenjing Liang,
Xiaobin Ling,
Jinbiao Ma,
Chuanwei Yang,
Lin Li
Affiliations
Yu Xie
State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, China
Wenbo Liu
Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, School of Life Sciences, Fudan University, Shanghai, China
Wenjing Liang
State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, China
Xiaobin Ling
State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China
Jinbiao Ma
State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China
Chuanwei Yang
Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, School of Life Sciences, Fudan University, Shanghai, China; Corresponding author
Lin Li
State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, China; Corresponding author
Summary: Shade-intolerant plants sense changes in the light environment and trigger shade-avoidance syndrome in the presence of neighboring vegetation. Phytochrome-interacting factor 7 (PIF7) is an essential regulator that integrates shade signals into plant transcriptional networks. While the regulation of PIF7 under shade conditions has been well studied, the mechanism that represses PIF7 activity under white light remains ambiguous. Here, we report that PIF7 forms nuclear puncta containing phase-separated liquid-like condensates. Phytochrome B (phyB) then binds to dephosphorylated PIF7 and promotes its condensed phase of PIF7 under white light. The phyB-PIF7 condensate subsequently inhibits the DNA-binding activity of PIF7. However, shade inactivation of phyB causes the dissociation of phyB-PIF7 condensates and allows unbound PIF7 to promote the transcription of shade-induced genes. This reversible transcriptional condensation via phase separation provides sessile organisms with the flexibility of gene control to adapt to their surrounding environment.
