Circadian Clock in Arabidopsis Roots Is a Simplified Slave Version of the Clock in Shoots

• Published in: Science (American Association for the Advancement of Science) Vol. 322; no. 5909; pp. 1832 - 1835
• Main Authors: James, Allan B, Monreal, José A, Nimmo, Gillian A, Kelly, Ciarán L, Herzyk, Pawel, Jenkins, Gareth I, Nimmo, Hugh G
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 19-12-2008; The American Association for the Advancement of Science
• Subjects: Agronomy. Soil science and plant productions; Antiserum; Arabidopsis; Arabidopsis - genetics; Arabidopsis - physiology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - physiology; Biological and medical sciences; Biological Clocks - genetics; Biological sciences; Botany; Circadian rhythm; Circadian Rhythm - genetics; Clocks; Control loops; Darkness; Diuron - pharmacology; DNA-Binding Proteins - genetics; DNA-Binding Proteins - physiology; Feedback; Feedback, Physiological; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Plant - drug effects; Genes; Genes, Plant; Genetics; Genetics and breeding of economic plants; Light; Oligonucleotide Array Sequence Analysis; Organ specificity; Photosynthesis; Plant cells; Plant roots; Plant Roots - genetics; Plant Roots - physiology; Plant Shoots - genetics; Plant Shoots - physiology; Plants; Promoter Regions, Genetic; Seedlings; Transcription Factors - genetics; Transcription Factors - physiology; Root; Feedback regulation; Circadian rhythm; Gene expression; Arabidopsis thaliana; Gene; Cruciferae; Dicotyledones; Angiospermae; Above ground plant part; Spermatophyta; Experimental plant; Transcription factor; Photosynthesis; Molecular clock; Maturity; Organ
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1161403

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.