title: Arabidopsis DOF transcription factors act redundantly to reduce CONSTANS expression and are essential for a photoperiodic flowering response.
abstract: Flowering of Arabidopsis is induced by long summer days (LDs). The transcriptional regulator CONSTANS (CO) promotes flowering, and its transcription is increased under LDs. We systematically misexpressed transcription factors in companion cells and identified several DOF proteins that delay flowering by repressing CO transcription. Combining mutations in four of these, including CYCLING DOF FACTOR 2 (CDF2), caused photoperiod-insensitive early flowering by increasing CO mRNA levels. CO transcription is promoted to differing extents by GIGANTEA (GI) and the F-box protein FKF1. We show that GI stabilizes FKF1, thereby reducing CDF2 abundance and allowing transcription of CO. Despite the crucial function of GI in wild-type plants, introducing mutations in the four DOF-encoding genes into gi mutants restored the diurnal rhythm and light inducibility of CO. Thus, antagonism between GI and DOF transcription factors contributes to photoperiodic flowering by modulating an underlying diurnal rhythm in CO transcript levels.
authors.affiliation: Max Planck Institute for Plant Breeding Research, Carl von Linné Weg 10, Cologne, Germany.
authors.forename: Fabio
authors.initials: F
authors.lastname: Fornara
authors.forename: Kishore C S
authors.initials: KC
authors.lastname: Panigrahi
authors.forename: Lionel
authors.initials: L
authors.lastname: Gissot
authors.forename: Nicolas
authors.initials: N
authors.lastname: Sauerbrunn
authors.forename: Mark
authors.initials: M
authors.lastname: Rühl
authors.forename: José A
authors.initials: JA
authors.lastname: Jarillo
authors.forename: George
authors.initials: G
authors.lastname: Coupland
mesh_terms: D017360:Arabidopsis / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002940:Circadian Rhythm / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D009154:Mutation; D017440:Photoperiod; D030821:Plants, Genetically Modified; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C543182:CDF2 protein, Arabidopsis; C092776:CONSTANS protein, Arabidopsis; D004268:DNA-Binding Proteins; C410504:FKF1 protein, Arabidopsis; C121183:GI protein, Arabidopsis; C450148:LKP2 protein, Arabidopsis; D012333:RNA, Messenger; D012097:Repressor Proteins; D014157:Transcription Factors; C410503:ZTL protein, Arabidopsis