UV-B perceived by the UVR8 photoreceptor inhibits plant thermomorphogenesis

Hayes, S., Sharma, A., Fraser, D. P., Trevisan, M., Cragg-Barber, C. K., Tavridou, E., Fankhauser, C., Jenkins, G. I. and Franklin, K. A. (2017) UV-B perceived by the UVR8 photoreceptor inhibits plant thermomorphogenesis. Current Biology, 27(1), pp. 120-127. (doi: 10.1016/j.cub.2016.11.004) (PMID:27989670) (PMCID:PMC5226890)

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Small increases in ambient temperature can elicit striking effects on plant architecture, collectively termed thermomorphogenesis [1]. In Arabidopsis thaliana, these include marked stem elongation and leaf elevation, responses that have been predicted to enhance leaf cooling [ 2, 3, 4 and 5]. Thermomorphogenesis requires increased auxin biosynthesis, mediated by the bHLH transcription factor PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) [ 6, 7 and 8], and enhanced stability of the auxin co-receptor TIR1, involving HEAT SHOCK PROTEIN 90 (HSP90) [9]. High-temperature-mediated hypocotyl elongation additionally involves localized changes in auxin metabolism, mediated by the indole-3-acetic acid (IAA)-amido synthetase Gretchen Hagen 3 (GH3).17 [10]. Here we show that ultraviolet-B light (UV-B) perceived by the photoreceptor UV RESISTANCE LOCUS 8 (UVR8) [11] strongly attenuates thermomorphogenesis via multiple mechanisms inhibiting PIF4 activity. Suppression of thermomorphogenesis involves UVR8 and CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1)-mediated repression of PIF4 transcript accumulation, reducing PIF4 abundance. UV-B also stabilizes the bHLH protein LONG HYPOCOTYL IN FAR RED (HFR1), which can bind to and inhibit PIF4 function. Collectively, our results demonstrate complex crosstalk between UV-B and high-temperature signaling. As plants grown in sunlight would most likely experience concomitant elevations in UV-B and ambient temperature, elucidating how these pathways are integrated is of key importance to the understanding of plant development in natural environments.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Jenkins, Professor Gareth
Authors: Hayes, S., Sharma, A., Fraser, D. P., Trevisan, M., Cragg-Barber, C. K., Tavridou, E., Fankhauser, C., Jenkins, G. I., and Franklin, K. A.
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:Current Biology
Publisher:Elsevier (Cell Press)
ISSN (Online):1879-0445
Published Online:15 December 2016
Copyright Holders:Copyright © 2017 The Authors
First Published:First published in Current Biology 27(1): 120-127
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
671211Integrating UV-B Signalling in to Plant Photomorphogenesis NetworksGareth JenkinsBiotechnology and Biological Sciences Research Council (BBSRC)BB/M008711/1RI MOLECULAR CELL & SYSTEMS BIOLOGY