title: The HY5-PIF regulatory module coordinates light and temperature control of photosynthetic gene transcription.
abstract: The ability to interpret daily and seasonal alterations in light and temperature signals is essential for plant survival. This is particularly important during seedling establishment when the phytochrome photoreceptors activate photosynthetic pigment production for photoautotrophic growth. Phytochromes accomplish this partly through the suppression of phytochrome interacting factors (PIFs), negative regulators of chlorophyll and carotenoid biosynthesis. While the bZIP transcription factor long hypocotyl 5 (HY5), a potent PIF antagonist, promotes photosynthetic pigment accumulation in response to light. Here we demonstrate that by directly targeting a common promoter cis-element (G-box), HY5 and PIFs form a dynamic activation-suppression transcriptional module responsive to light and temperature cues. This antagonistic regulatory module provides a simple, direct mechanism through which environmental change can redirect transcriptional control of genes required for photosynthesis and photoprotection. In the regulation of photopigment biosynthesis genes, HY5 and PIFs do not operate alone, but with the circadian clock. However, sudden changes in light or temperature conditions can trigger changes in HY5 and PIFs abundance that adjust the expression of common target genes to optimise photosynthetic performance and growth.
authors.affiliation: Institute of Structural and Molecular Biology, SynthSys, University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Toledo-Ortiz
authors.affiliation: Institute of Structural and Molecular Biology, SynthSys, University of Edinburgh, Edinburgh, United Kingdom; Plant Physiology, Justus Liebig University, Senckernbergstr, Giessen, Germany.
authors.forename: Henrik
authors.initials: H
authors.lastname: Johansson
authors.affiliation: Institute of Structural and Molecular Biology, SynthSys, University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: Keun Pyo
authors.initials: KP
authors.lastname: Lee
authors.affiliation: Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, Barcelona, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Bou-Torrent
authors.affiliation: Institute of Structural and Molecular Biology, SynthSys, University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: Kelly
authors.initials: K
authors.lastname: Stewart
authors.affiliation: Institute of Structural and Molecular Biology, SynthSys, University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: Gavin
authors.initials: G
authors.lastname: Steel
authors.affiliation: Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, Barcelona, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Rodríguez-Concepción
authors.affiliation: Institute of Structural and Molecular Biology, SynthSys, University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Halliday
mesh_terms: D017360:Arabidopsis / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000096:biosynthesis / Q000235:genetics*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics*; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics*; D002338:Carotenoids / Q000096:biosynthesis; D002734:Chlorophyll / Q000096:biosynthesis; D051790:G-Box Binding Factors / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D009687:Nuclear Proteins / Q000235:genetics*; D017440:Photoperiod; D010788:Photosynthesis / Q000235:genetics*; D011401:Promoter Regions, Genetic; D018000:Receptors, Peptide / Q000096:biosynthesis; D012621:Seasons; D013696:Temperature; D014158:Transcription, Genetic; D015533:Transcriptional Activation / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D002338:Carotenoids; D002734:Chlorophyll; D051790:G-Box Binding Factors; D009687:Nuclear Proteins; D018000:Receptors, Peptide; C109254:HY5 protein, Arabidopsis; C508068:At2g20180 protein, Arabidopsis; C000588888:PSY1R protein, Arabidopsis