SHB1 and CCA1 interaction desensitizes light responses and enhances thermomorphogenesis

Qingbin Sun, Shulei Wang, Gang Xu, Xiaojun Kang, Min Zhang, Min Ni

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Light and temperature are two important environmental signals to plants. After dawn, photo-activated phytochromes translocate into the nucleus and interact with a family of negative basic helix-loop-helix PIF regulators. Subsequent phosphorylation and degradation of PIFs triggers a series of photomorphogenic responses. However, excess light can damage the photosynthetic apparatus and leads to photoinhibition. Plants acclimate to a balanced state of photomorphogenesis to avoid photodamage. Here, we show that upregulation of PIF4 expression by SHB1 and CCA1 under red light represents a desensitization step. After dawn, the highly expressed circadian clock protein CCA1 brings circadian signals to the regulatory region of the PIF4 signaling hub. Recruitment of SHB1 by CCA1 modulates red light-specific induction of PIF4 expression thus integrating circadian and light signals. As noon approaches and light intensity and ambient temperature tend to increase, the SHB1–CCA1 interaction sustains PIF4 expression to trigger thermomorphogenic responses to changing light and temperature conditions.

Original languageEnglish (US)
Article number3110
JournalNature communications
Issue number1
StatePublished - Dec 1 2019

Bibliographical note

Funding Information:
seeds and ABRC for lhy-21 seeds. This work was supported by a grant from National Natural Science Foundation of China (31470379) and a grant from the USDA National Institution of Food and Agriculture grant 2011–67013–30150.

Publisher Copyright:
© 2019, The Author(s).


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