Regulation of UVR8 photoreceptor dimer/monomer photo-equilibrium in Arabidopsis plants grown under photoperiodic conditions

Findlay, K. M.W. and Jenkins, G. I. (2016) Regulation of UVR8 photoreceptor dimer/monomer photo-equilibrium in Arabidopsis plants grown under photoperiodic conditions. Plant Cell and Environment, 39(8), pp. 1706-1714. (doi: 10.1111/pce.12724) (PMID:26864532) (PMCID:PMC5103188)

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The UV RESISTANCE LOCUS 8 (UVR8) photoreceptor specifically mediates photomorphogenic responses to UV-B. Photoreception induces dissociation of dimeric UVR8 into monomers to initiate responses. However, the regulation of dimer/monomer status in plants growing under photoperiodic conditions has not been examined. Here we show that UVR8 establishes a dimer/monomer photo-equilibrium in plants growing in diurnal photoperiods in both controlled environments and natural daylight. The photo-equilibrium is determined by the relative rates of photoreception and dark-reversion to the dimer. Experiments with mutants in REPRESSOR OF UV-B PHOTOMORPHOGENESIS 1 (RUP1) and RUP2 show that these proteins are crucial in regulating the photo-equilibrium because they promote reversion to the dimer. In plants growing in daylight, the UVR8 photo-equilibrium is most strongly correlated with low ambient fluence rates of UV-B (up to 1.5 µmol m−2 s−1), rather than higher fluence rates or the amount of photosynthetically active radiation. In addition, the rate of reversion of monomer to dimer is reduced at lower temperatures, promoting an increase in the relative level of monomer at approximately 8–10 °C. Thus, UVR8 does not behave like a simple UV-B switch under photoperiodic growth conditions but establishes a dimer/monomer photo-equilibrium that is regulated by UV-B and also influenced by temperature.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Jenkins, Professor Gareth
Authors: Findlay, K. M.W., and Jenkins, G. I.
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:Plant Cell and Environment
ISSN (Online):1365-3040
Published Online:06 May 2016
Copyright Holders:Copyright © 2016 The Authors
First Published:First published in Plant Cell and Environment 39(8):1706-1714
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
500151Doctoral Training Grant 2009-15Timothy PalmerBiotechnology and Biological Sciences Research Council (BBSRC)BB/F016735/1RI CARDIOVASCULAR & MEDICAL SCIENCES