Interaction of COP1 and UVR8 regulates UV-B-induced photomorphogenesis and stress acclimation in Arabidopsis.
The ultraviolet-B (UV-B) portion of the solar radiation functions as an environmental signal for which plants have evolved specific and sensitive UV-B perception systems. The UV-B-specific UV RESPONSE LOCUS 8 (UVR8) and the multifunctional E3 ubiquitin ligase CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) are key regulators of the UV-B response. We show here that uvr8-null mutants are deficient in UV-B-induced photomorphogenesis and hypersensitive to UV-B stress, whereas overexpression of UVR8 results in enhanced UV-B photomorphogenesis, acclimation and tolerance to UV-B stress. By using sun simulators, we provide evidence at the physiological level that UV-B acclimation mediated by the UV-B-specific photoregulatory pathway is indeed required for survival in sunlight. At the molecular level, we demonstrate that the wild type but not the mutant UVR8 and COP1 proteins directly interact in a UV-B-dependent, rapid manner in planta. These data collectively suggest that UV-B-specific interaction of COP1 and UVR8 in the nucleus is a very early step in signalling and responsible for the plant's coordinated response to UV-B ensuring UV-B acclimation and protection in the natural environment.
Favory
Jean-Jacques
JJ
Faculty of Biology, Institute of Biology II, University of Freiburg, Freiburg, Germany.
Stec
Agnieszka
A
Gruber
Henriette
H
Rizzini
Luca
L
Oravecz
Attila
A
Funk
Markus
M
Albert
Andreas
A
Cloix
Catherine
C
Jenkins
Gareth I
GI
Oakeley
Edward J
EJ
Seidlitz
Harald K
HK
Nagy
Ferenc
F
Ulm
Roman
R
D000064:Acclimatization; D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D018546:Hypocotyl / Q000254:growth & development / Q000502:physiology; D009154:Mutation; D011485:Protein Binding; D015398:Signal Transduction / Q000502:physiology; D013312:Stress, Physiological; D013472:Sunlight; D044767:Ubiquitin-Protein Ligases; D014466:Ultraviolet Rays
D029681:Arabidopsis Proteins; D002868:Chromosomal Proteins, Non-Histone; C525052:Uvr8 protein, Arabidopsis; C471983:AT2G32950 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases