Arabidopsis phytochromes A and B synergistically repress SPA1 under blue light. Issue 4 (15th March 2023)

• Record Type: Journal Article
• Authors: Jia, Xiaolin; Song, Meifang; Wang, Shaoci; Liu, Tong; Wang, Lijian; Guo, Lin; Su, Liang; Shi, Yong; Zheng, Xu; Yang, Jianping
• Is Part Of: Journal of integrative plant biology. Volume 65:Issue 4(2023)
• Page Start: 888
• Page End: 894
• Publication Date: 2023-03-15
• Subjects: Arabidopsis -- blue light -- phytochrome -- SPA1; Plants -- Periodicals; Plants -- China -- Periodicals; Electronic journals; 580.5
• DOI: 10.1111/jipb.13412
• Languages: English
• ISSNs: 1672-9072

Abstract

Summary: In Arabidopsis, although studies have demonstrated that phytochrome A (phyA) and phyB are involved in blue light signaling, how blue light‐activated phytochromes modulate the activity of the CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1)‐SUPPRESSOR OF PHYA‐105 (SPA1) E3 complex remains largely unknown. Here, we show that phyA responds to early and weak blue light, whereas phyB responds to sustainable and strong blue light. Activation of both phyA and phyB by blue light inhibits SPA1 activity. Specifically, blue light irradiation promoted the nuclear import of both phytochromes to stimulate their binding to SPA1, abolishing SPA1's interaction with LONG HYPOCOTYL 5 (HY5) to release HY5, which promoted seedling photomorphogenesis. Abstract : Blue‐light irradiation promotes the nuclear import of phytochromes a and b to stimulate their binding to SUPPRESSOR OF PHYA‐105 (SPA1), abolishing the SPA1‐HY5 interaction and thus releasing HY5, which promotes seedling photomorphogenesis.