The circadian clock in Arabidopsis roots is a simplified slave version of the clock in shoots.
The circadian oscillator in eukaryotes consists of several interlocking feedback loops through which the expression of clock genes is controlled. It is generally assumed that all plant cells contain essentially identical and cell-autonomous multiloop clocks. Here, we show that the circadian clock in the roots of mature Arabidopsis plants differs markedly from that in the shoots and that the root clock is synchronized by a photosynthesis-related signal from the shoot. Two of the feedback loops of the plant circadian clock are disengaged in roots, because two key clock components, the transcription factors CCA1 and LHY, are able to inhibit gene expression in shoots but not in roots. Thus, the plant clock is organ-specific but not organ-autonomous.
James
Allan B
AB
Division of Molecular and Cellular Biology, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
Monreal
José A
JA
Nimmo
Gillian A
GA
Kelly
Ciarán L
CL
Herzyk
Pawel
P
Jenkins
Gareth I
GI
Nimmo
Hugh G
HG
D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D001683:Biological Clocks / Q000235:genetics; D002940:Circadian Rhythm / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology; D003624:Darkness; D004237:Diuron / Q000494:pharmacology; D025461:Feedback, Physiological; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D008027:Light; D020411:Oligonucleotide Array Sequence Analysis; D010788:Photosynthesis; D018517:Plant Roots / Q000235:genetics / Q000502:physiology*; D018520:Plant Shoots / Q000235:genetics / Q000502:physiology; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology
D029681:Arabidopsis Proteins; C114425:CCA1 protein, Arabidopsis; D004268:DNA-Binding Proteins; C113192:LHY protein, Arabidopsis; C411822:TOC1 protein, Arabidopsis; D014157:Transcription Factors; D004237:Diuron