Research Repository

A Constitutively Active Allele of Phytochrome B Maintains Circadian Robustness in the Absence of Light

Jones, Matthew A and Hu, Wei and Litthauer, Suzanne and Lagarias, J. Clark and Harmer, Stacey Lynn (2015) 'A Constitutively Active Allele of Phytochrome B Maintains Circadian Robustness in the Absence of Light.' Plant Physiology, 169 (1). pp. 814-825. ISSN 0032-0889

[img]
Preview
Text
Plant Physiol.-2015-Jones-814-25.pdf - Published Version

Download (8MB) | Preview

Abstract

The sensitivity of the circadian system to light allows entrainment of the clock, permitting coordination of plant metabolic function and flowering time across seasons. Light affects the circadian system via both photoreceptors, such as phytochromes and cryptochromes, and sugar production by photosynthesis. In the present study, we introduce a constitutively active version of phytochrome B-Y276H (YHB) into both wild-type and phytochrome null backgrounds of Arabidopsis (Arabidopsis thaliana) to distinguish the effects of photoreceptor signaling on clock function from those of photosynthesis. We find that the YHB mutation is sufficient to phenocopy red light input into the circadian mechanism and to sustain robust rhythms in steady-state mRNA levels even in plants grown without light or exogenous sugars. The pace of the clock is insensitive to light intensity in YHB plants, indicating that light input to the clock is constitutively activated by this allele. Mutation of YHB so that it is retained in the cytoplasm abrogates its effects on clock function, indicating that nuclear localization of phytochrome is necessary for its clock regulatory activity. We also demonstrate a role for phytochrome C as part of the red light sensing network that modulates phytochrome B signaling input into the circadian system. Our findings indicate that phytochrome signaling in the nucleus plays a critical role in sustaining robust clock function under red light, even in the absence of photosynthesis or exogenous sources of energy.

Item Type: Article
Subjects: Q Science > QH Natural history > QH301 Biology
Divisions: Faculty of Science and Health > Biological Sciences, School of
Depositing User: Jim Jamieson
Date Deposited: 02 Oct 2015 09:25
Last Modified: 02 Oct 2015 09:25
URI: http://repository.essex.ac.uk/id/eprint/15180

Actions (login required)

View Item View Item