title: The GI-CDF module of Arabidopsis affects freezing tolerance and growth as well as flowering.
abstract: Plants monitor and integrate temperature, photoperiod and light quality signals to respond to continuous changes in their environment. The GIGANTEA (GI) protein is central in diverse signaling pathways, including photoperiodic, sugar and light signaling pathways, stress responses and circadian clock regulation. Previously, GI was shown to activate expression of the key floral regulators CONSTANS (CO) and FLOWERING LOCUS T (FT) by facilitating degradation of a family of CYCLING DOF FACTOR (CDF) transcriptional repressors. However, whether CDFs are implicated in other processes affected by GI remains unclear. We investigated the contribution of the GI-CDF module to traits that depend on GI. Transcriptome profiling indicated that mutations in GI and the CDF genes have antagonistic effects on expression of a wider set of genes than CO and FT, whilst other genes are regulated by GI independently of the CDFs. Detailed expression studies followed by phenotypic assays showed that the CDFs function downstream of GI, influencing responses to freezing temperatures and growth, but are not necessary for proper clock function. Thus GI-mediated regulation of CDFs contributes to several processes in addition to flowering, but is not implicated in all of the traits influenced by GI.
authors.affiliation: Max Planck Institute for Plant Breeding Research, Carl von Linné Weg 10, D-50829, Cologne, Germany; Department of Biosciences, University of Milan, Via Celoria 26, 20133, Milan, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Fornara
authors.forename: Amaury
authors.initials: A
authors.lastname: de Montaigu
authors.forename: Alfredo
authors.initials: A
authors.lastname: Sánchez-Villarreal
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Emiel
authors.initials: E
authors.lastname: Ver Loren van Themaat
authors.forename: Bruno
authors.initials: B
authors.lastname: Huettel
authors.forename: Seth J
authors.initials: SJ
authors.lastname: Davis
authors.forename: George
authors.initials: G
authors.lastname: Coupland
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D057906:Circadian Clocks; D018548:Cotyledon / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D035264:Flowers; D005615:Freezing; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D018546:Hypocotyl / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D008027:Light; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress; D010641:Phenotype; D017440:Photoperiod; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C502170:CDF1 protein, Arabidopsis; C543182:CDF2 protein, Arabidopsis; C121183:GI protein, Arabidopsis; D012097:Repressor Proteins; D014157:Transcription Factors
keywords: Arabidopsis thaliana; CYCLING DOF FACTOR; GIGANTEA; circadian clock; flowering; freezing tolerance; growth