Functional interaction of the circadian clock and UV RESISTANCE LOCUS 8-controlled UV-B signaling pathways in Arabidopsis thaliana

Fehér, Balázs; Kozma-Bognár, László; Kevei, Eva; Hajdu, Anita; Binkert, Melanie; Davis, Seth Jon; Schäfer, Eberhard; Ulm, Roman; Nagy, Ferenc

doi:10.1111/j.1365-313X.2011.04573.x

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Title		Functional interaction of the circadian clock and UV RESISTANCE LOCUS 8-controlled UV-B signaling pathways in Arabidopsis thaliana
Authors		Fehér, Balázs Kozma-Bognár, László Kevei, Eva Hajdu, Anita Binkert, Melanie Davis, Seth Jon Schäfer, Eberhard Ulm, Roman Nagy, Ferenc show all authors [1 - 9]
Published in		The Plant Journal. 2011, vol. 67, no. 1, p. 37-48
Abstract		Circadian clocks regulate many molecular and physiological processes in Arabidopsis (Arabidopsis thaliana), allowing the timing of these processes to occur at the most appropriate time of the day in a 24-h period. The accuracy of timing relies on the synchrony of the clock and the environmental day/night cycle. Visible light is the most potent signal for such synchronization, but light-induced responses are also rhythmically attenuated (gated) by the clock. Here, we report a similar mutual interaction of the circadian clock and non-damaging photomorphogenic UV-B light. We show that low-intensity UV-B radiation acts as entraining signal for the clock. UV RESISTANCE LOCUS 8 (UVR8) and CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) are required, but ELONGATED HYPOCOTYL 5 (HY5) and HY5 HOMOLOG (HYH) are dispensable for this process. UV-B responsiveness of clock gene expression suggests that photomorphogenic UV-B entrains the plant clock through transcriptional activation. We also demonstrate that UV-B induction of gene expression under these conditions is gated by the clock in a HY5/HYH-independent manner. The arrhythmic early flowering 3-4 mutant showed non-gated, high-level gene induction by UV-B, yet displayed no increased tolerance to UV-B stress. Thus, the temporal restriction of UV-B responsiveness by the circadian clock can be considered as saving resources during acclimation without losing fitness.
Keywords		Arabidopsis/genetics/physiology/radiation effects — Arabidopsis Proteins/genetics/metabolism/physiology — Basic-Leucine Zipper Transcription Factors/physiology — Carrier Proteins/physiology — Chromosomal Proteins, Non-Histone/genetics/metabolism — Circadian Clocks/physiology/radiation effects — Circadian Rhythm/physiology/radiation effects — Gene Expression Regulation, Plant/radiation effects — Mutation — Nuclear Proteins/physiology — Photoperiod — Signal Transduction/physiology — Stress, Physiological — Time Factors — Transcription Factors/genetics/metabolism — Transcriptional Activation — Ultraviolet Rays
Identifiers		DOI: 10.1111/j.1365-313X.2011.04573.x PMID: 21395889
Full text		Article (Published version) (1 MB) - Limited access to UNIGE
Citation (ISO format)		FEHÉR, Balázs et al. Functional interaction of the circadian clock and UV RESISTANCE LOCUS 8-controlled UV-B signaling pathways in Arabidopsis thaliana. In: The Plant Journal, 2011, vol. 67, n° 1, p. 37-48. doi: 10.1111/j.1365-313X.2011.04573.x https://archive-ouverte.unige.ch/unige:19321