A dynamic model of UVR8 photoreceptor signaling in UV-B acclimated Arabidopsis

Liao, X., Liu, W. , Yang, H.-Q. and Jenkins, G. I. (2020) A dynamic model of UVR8 photoreceptor signaling in UV-B acclimated Arabidopsis. New Phytologist, (doi: 10.1111/nph.16581) (PMID:32255498) (Early Online Publication)

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The photoreceptor UVR8 mediates numerous photomorphogenic responses of plants to UV‐B wavelengths by regulating transcription. Studies with purified UVR8 and seedlings not previously exposed to UV‐B have generated a model for UVR8 action in which dimeric UVR8 rapidly monomerises in response to UV‐B exposure to initiate signaling. However, the mechanism of UVR8 action in UV‐B‐acclimated plants growing under photoperiodic conditions, where UVR8 exists in a dimer/monomer photo‐equilibrium, is poorly understood. We examined UVR8 dimer/monomer status, gene expression responses, amounts of key UVR8 signaling proteins and their interactions with UVR8 in UV‐B‐acclimated Arabidopsis. We show that in UV‐B‐acclimated plants UVR8 can mediate a response to a 15‐fold increase in UV‐B without any increase in abundance of UVR8 monomer. Following transfer to elevated UV‐B, monomers show increased interaction with both COP1, to initiate signaling, and RUP2, to maintain the photo‐equilibrium when the dimer/monomer cycling rate increases. Native RUP1 is present in low abundance compared with RUP2. We present a model for UVR8 action in UV‐B‐acclimated plants growing in photoperiodic conditions that incorporates dimer and monomer photoreception, dimer/monomer cycling, abundance of native COP1 and RUP proteins, and interactions of the monomer population with COP1, RUP2 and potentially other proteins.

Item Type:Articles
Status:Early Online Publication
Glasgow Author(s) Enlighten ID:Liao, Xinyang and Jenkins, Professor Gareth and Liu, Miss Wei
Authors: Liao, X., Liu, W., Yang, H.-Q., and Jenkins, G. I.
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:New Phytologist
ISSN (Online):1469-8137
Published Online:07 April 2020
Copyright Holders:Copyright © 2020 The Authors
First Published:First published in New Phytologist 2020
Publisher Policy:Reproduced under a Creative Commons License

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