Organ specificity in the plant circadian system is explained by different light inputs to the shoot and root clocks

Bordage, S., Sullivan, S. , Laird, J., Millar, A. J. and Nimmo, H. G. (2016) Organ specificity in the plant circadian system is explained by different light inputs to the shoot and root clocks. New Phytologist, 212(1), pp. 136-149. (doi: 10.1111/nph.14024) (PMID:27240972) (PMCID:PMC5006879)

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Circadian clocks allow the temporal compartmentalisation of biological processes. In Arabidopsis circadian rhythms display organ specificity but the underlying molecular causes have not been identified. We investigated the mechanisms responsible for the similarities and differences between the clocks of mature shoots and roots in constant conditions and in light:dark cycles. We developed an imaging system to monitor clock gene expression in shoots and light- or dark-grown roots, modified a recent mathematical model of the Arabidopsis clock and used this to simulate our new data. We showed that the shoot and root circadian clocks have different rhythmic properties (period and amplitude) and respond differently to light quality. The root clock was entrained by direct exposure to low-intensity light, even in antiphase to the illumination of shoots. Differences between the clocks were more pronounced in conditions where light is present than in constant darkness, and persisted in the presence of sucrose. We simulated the data successfully by modifying those parameters of a clock model that are related to light inputs. We conclude that differences and similarities between the shoot and root clocks can largely be explained by organ-specific light inputs. This provides mechanistic insight into the developing field of organ-specific clocks.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Nimmo, Professor Hugh and Bordage, Mr Simon and Sullivan, Dr Stuart and Laird, Ms Janet
Authors: Bordage, S., Sullivan, S., Laird, J., Millar, A. J., and Nimmo, H. G.
College/School:College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
Journal Name:New Phytologist
ISSN (Online):1469-8137
Published Online:31 May 2016
Copyright Holders:Copyright © 2016 The Authors
First Published:First published in New Phytologist 212(1):136-149
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
510981Protein function underlying plasticity of the plant circadian clockHugh NimmoBiotechnology and Biological Sciences Research Council (BBSRC)BB/H000135/1RI MOLECULAR CELL & SYSTEMS BIOLOGY