title: TOC1-PIF4 interaction mediates the circadian gating of thermoresponsive growth in Arabidopsis.
abstract: Arabidopsis adapts to elevated temperature by promoting stem elongation and hyponastic growth through a temperature-responsive transcription factor PIF4. Here we show that the evening-expressed clock component TOC1 interacts with and inactivates PIF4, thereby suppressing thermoresponsive growth in the evening. We find that the expression of PIF4 target genes show circadian rhythms of thermosensitivity, with minimum responsiveness in the evening when TOC1 level is high. Loss of function of TOC1 and its close homologue PRR5 restores thermosensitivity in the evening, whereas TOC1 overexpression causes thermo insensitivity, demonstrating that TOC1 mediates the evening-specific inhibition of thermoresponses. We further show that PIF4 is required for thermoadaptation mediated by moderately elevated temperature. Our results demonstrate that the interaction between TOC1 and PIF4 mediates the circadian gating of thermoresponsive growth, which may serve to increase fitness by matching thermoresponsiveness with the day-night cycles of fluctuating temperature and light conditions.
authors.affiliation: Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, USA.
authors.forename: Jia-Ying
authors.initials: JY
authors.lastname: Zhu
authors.affiliation: Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, USA.|Department of Bioenergy Science and Technology, Chonnam National University, Gwangju 61186, Korea.
authors.forename: Eunkyoo
authors.initials: E
authors.lastname: Oh
authors.affiliation: Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, USA.
authors.forename: Tina
authors.initials: T
authors.lastname: Wang
authors.affiliation: Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, USA.
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Wang
mesh_terms: D000222:Adaptation, Physiological; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002940:Circadian Rhythm; D013696:Temperature; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D014157:Transcription Factors; C459466:PIF4 protein, Arabidopsis; C411822:TOC1 protein, Arabidopsis