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Coordinated circadian timing through the integration of local inputs in Arabidopsis thaliana.

Published version
Peer-reviewed

Type

Article

Change log

Abstract

Individual plant cells have a genetic circuit, the circadian clock, that times key processes to the day-night cycle. These clocks are aligned to the day-night cycle by multiple environmental signals that vary across the plant. How does the plant integrate clock rhythms, both within and between organs, to ensure coordinated timing? To address this question, we examined the clock at the sub-tissue level across Arabidopsis thaliana seedlings under multiple environmental conditions and genetic backgrounds. Our results show that the clock runs at different speeds (periods) in each organ, which causes the clock to peak at different times across the plant in both constant environmental conditions and light-dark (LD) cycles. Closer examination reveals that spatial waves of clock gene expression propagate both within and between organs. Using a combination of modeling and experiment, we reveal that these spatial waves are the result of the period differences between organs and local coupling, rather than long-distance signaling. With further experiments we show that the endogenous period differences, and thus the spatial waves, can be generated by the organ specificity of inputs into the clock. We demonstrate this by modulating periods using light and metabolic signals, as well as with genetic perturbations. Our results reveal that plant clocks can be set locally by organ-specific inputs but coordinated globally via spatial waves of clock gene expression.

Description

Keywords

Arabidopsis, Arabidopsis Proteins, Circadian Clocks, Circadian Rhythm, Gene Expression Regulation, Plant, Gene Regulatory Networks, Organ Specificity, Photoperiod, Seedlings, Signal Transduction, Transcription Factors

Journal Title

PLoS Biol

Conference Name

Journal ISSN

1544-9173
1545-7885

Volume Title

17

Publisher

Public Library of Science (PLoS)
Sponsorship
Biotechnology and Biological Sciences Research Council (BB/K017152/1)
Gatsby Charitable Foundation (unknown)