Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom; Department of Mathematical Sciences, University of Liverpool, Liverpool, United Kingdom
Mark Greenwood
Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom; Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom; Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary; Department of Genetics, University of Szeged, Szeged, Hungary
Anthony JW Hall
Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom; Earlham Institute, Norwich Research Park, Norwich, United Kingdom
Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom; Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom; Microsoft Research, Cambridge, United Kingdom
The Arabidopsis circadian clock orchestrates gene regulation across the day/night cycle. Although a multiple feedback loop circuit has been shown to generate the 24-hr rhythm, it remains unclear how robust the clock is in individual cells, or how clock timing is coordinated across the plant. Here we examine clock activity at the single cell level across Arabidopsis seedlings over several days under constant environmental conditions. Our data reveal robust single cell oscillations, albeit desynchronised. In particular, we observe two waves of clock activity; one going down, and one up the root. We also find evidence of cell-to-cell coupling of the clock, especially in the root tip. A simple model shows that cell-to-cell coupling and our measured period differences between cells can generate the observed waves. Our results reveal the spatial structure of the plant clock and suggest that unlike the centralised mammalian clock, the Arabidopsis clock has multiple coordination points.
