Light receptor action is critical for maintaining plant biomass at warm ambient temperatures.
The ability to withstand environmental temperature variation is essential for plant survival. Former studies in Arabidopsis revealed that light signalling pathways had a potentially unique role in shielding plant growth and development from seasonal and daily fluctuations in temperature. In this paper we describe the molecular circuitry through which the light receptors cry1 and phyB buffer the impact of warm ambient temperatures. We show that the light signalling component HFR1 acts to minimise the potentially devastating effects of elevated temperature on plant physiology. Light is known to stabilise levels of HFR1 protein by suppressing proteasome-mediated destruction of HFR1. We demonstrate that light-dependent accumulation and activity of HFR1 are highly temperature dependent. The increased potency of HFR1 at warmer temperatures provides an important restraint on PIF4 that drives elongation growth. We show that warm ambient temperatures promote the accumulation of phosphorylated PIF4. However, repression of PIF4 activity by phyB and cry1 (via HFR1) is critical for controlling growth and maintaining physiology as temperatures rise. Loss of this light-mediated restraint has severe consequences for adult plants which have greatly reduced biomass.
Department of Biological Sciences, CH Waddington Building, Kings Buildings, University of Edinburgh, Edinburgh, UK.
Julia
J
Foreman
Henrik
H
Johansson
Patricia
P
Hornitschek
Eve-Marie
EM
Josse
Christian
C
Fankhauser
Karen J
KJ
Halliday
D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D018533:Biomass; D056931:Cryptochromes / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D008027:Light; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D010766:Phosphorylation; D051939:Phytochrome B / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D015398:Signal Transduction / Q000528:radiation effects; D013696:Temperature
D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D056931:Cryptochromes; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D051939:Phytochrome B; C538962:CRY1 protein, Arabidopsis; C414438:At1g02340 protein, Arabidopsis; C497952:PHYB protein, Arabidopsis; C459466:PIF4 protein, Arabidopsis; C497729:PIF5 protein, Arabidopsis