UV-B Perceived by the UVR8 Photoreceptor Inhibits Plant Thermomorphogenesis

Scott Hayes, Ashutosh Sharma, Donald P. Fraser, Martine Trevisan, Kester Cragg-Barber, Eleni Tavridou, Christian Fankhauser, Gareth I. Jenkins, Keara A. Franklin*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

78 Citations (Scopus)

Abstract

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 [2–5]. Thermomorphogenesis requires increased auxin biosynthesis, mediated by the bHLH transcription factor PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) [6–8], 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.

Original languageEnglish
Pages (from-to)120-127
Number of pages8
JournalCurrent Biology
Volume27
Issue number1
DOIs
Publication statusPublished - 9 Jan 2017
Externally publishedYes

Keywords

  • Arabidopsis
  • auxin
  • HFR1
  • high temperature
  • hypocotyl
  • PIF4
  • UV-B
  • UVR8

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