title: UV-B detected by the UVR8 photoreceptor antagonizes auxin signaling and plant shade avoidance.
abstract: Plants detect different facets of their radiation environment via specific photoreceptors to modulate growth and development. UV-B is perceived by the photoreceptor UV RESISTANCE LOCUS 8 (UVR8). The molecular mechanisms linking UVR8 activation to plant growth are not fully understood, however. When grown in close proximity to neighboring vegetation, shade-intolerant plants initiate dramatic stem elongation to overtop competitors. Here we show that UV-B, detected by UVR8, provides an unambiguous sunlight signal that inhibits shade avoidance responses in Arabidopsis thaliana by antagonizing the phytohormones auxin and gibberellin. UV-B triggers degradation of the transcription factors PHYTOCHROME INTERACTING FACTOR 4 and PHYTOCHROME INTERACTING FACTOR 5 and stabilizes growth-repressing DELLA proteins, inhibiting auxin biosynthesis via a dual mechanism. Our findings show that UVR8 signaling is closely integrated with other photoreceptor pathways to regulate auxin signaling and plant growth in sunlight.
authors: School of Biological Sciences, University of Bristol, Bristol BS8 1UG, United Kingdom and.
authors: Scott
authors: S
authors: Hayes
authors: Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
authors: Christos N
authors: CN
authors: Velanis
authors: Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
authors: Gareth I
authors: GI
authors: Jenkins
authors: School of Biological Sciences, University of Bristol, Bristol BS8 1UG, United Kingdom and kerry.franklin@bristol.ac.uk.
authors: Keara A
authors: KA
authors: Franklin
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*; D004268:DNA-Binding Proteins; D017343:Genes, Plant; D005875:Gibberellins / Q000378:metabolism / Q000528:radiation effects; D007210:Indoleacetic Acids / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D055519:Photoreceptors, Plant / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*; D030821:Plants, Genetically Modified; D055550:Protein Stability / Q000528:radiation effects; D059748:Proteolysis / Q000528:radiation effects; D015398:Signal Transduction / Q000528:radiation effects; D013472:Sunlight; D014466:Ultraviolet Rays
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D002352:Carrier Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D005875:Gibberellins; D007210:Indoleacetic Acids; D009687:Nuclear Proteins; D055519:Photoreceptors, Plant; C109555:GAI protein, Arabidopsis; C109254:HY5 protein, Arabidopsis; C457459:HYH protein, Arabidopsis; C459466:PIF4 protein, Arabidopsis; C497729:PIF5 protein, Arabidopsis; C525052:Uvr8 protein, Arabidopsis