title: Linked circadian outputs control elongation growth and flowering in response to photoperiod and temperature.
abstract: Clock-regulated pathways coordinate the response of many developmental processes to changes in photoperiod and temperature. We model two of the best-understood clock output pathways in Arabidopsis, which control key regulators of flowering and elongation growth. In flowering, the model predicted regulatory links from the clock to cycling DOF factor 1 (CDF1) and flavin-binding, KELCH repeat, F-box 1 (FKF1) transcription. Physical interaction data support these links, which create threefold feed-forward motifs from two clock components to the floral regulator FT. In hypocotyl growth, the model described clock-regulated transcription of phytochrome-interacting factor 4 and 5 (PIF4, PIF5), interacting with post-translational regulation of PIF proteins by phytochrome B (phyB) and other light-activated pathways. The model predicted bimodal and end-of-day PIF activity profiles that are observed across hundreds of PIF-regulated target genes. In the response to temperature, warmth-enhanced PIF4 activity explained the observed hypocotyl growth dynamics but additional, temperature-dependent regulators were implicated in the flowering response. Integrating these two pathways with the clock model highlights the molecular mechanisms that coordinate plant development across changing conditions.
authors.affiliation: SynthSys and School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Seaton
authors.affiliation: SynthSys and School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Smith
authors.affiliation: Department of Biology, University of Washington, Seattle, WA, USA.
authors.forename: Young Hun
authors.initials: YH
authors.lastname: Song
authors.affiliation: Biosciences, University of Exeter, Exeter, UK.
authors.forename: Dana R
authors.initials: DR
authors.lastname: MacGregor
authors.affiliation: SynthSys and School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
authors.forename: Kelly
authors.initials: K
authors.lastname: Stewart
authors.affiliation: SynthSys and School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
authors.forename: Gavin
authors.initials: G
authors.lastname: Steel
authors.affiliation: SynthSys and School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
authors.forename: Julia
authors.initials: J
authors.lastname: Foreman
authors.affiliation: Biosciences, University of Exeter, Exeter, UK.
authors.forename: Steven
authors.initials: S
authors.lastname: Penfield
authors.affiliation: Department of Biology, University of Washington, Seattle, WA, USA.
authors.forename: Takato
authors.initials: T
authors.lastname: Imaizumi
authors.affiliation: SynthSys and School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Millar
authors.affiliation: SynthSys and School of Biological Sciences, University of Edinburgh, Edinburgh, UK karen.halliday@ed.ac.uk.
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Halliday
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D057906:Circadian Clocks / Q000235:genetics; D002940:Circadian Rhythm; D030541:Databases, Genetic; D035264:Flowers / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D018546:Hypocotyl / Q000254:growth & development*; D008027:Light; D017440:Photoperiod; D051939:Phytochrome B / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000302:isolation & purification*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013696:Temperature; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D051939:Phytochrome B; D012333:RNA, Messenger; D018749:RNA, Plant; D012097:Repressor Proteins; D014157:Transcription Factors; C502170:CDF1 protein, Arabidopsis; C410504:FKF1 protein, Arabidopsis; C586769:IAA29 protein, Arabidopsis; C497952:PHYB protein, Arabidopsis; C459466:PIF4 protein, Arabidopsis; C497729:PIF5 protein, Arabidopsis
keywords: gene regulatory networks; heat; hypocotyl elongation; photoperiodism; seasonal breeding