title: UV-B photoreceptor-mediated protection of the photosynthetic machinery in Chlamydomonas reinhardtii.
abstract: Life on earth is dependent on the photosynthetic conversion of light energy into chemical energy. However, absorption of excess sunlight can damage the photosynthetic machinery and limit photosynthetic activity, thereby affecting growth and productivity. Photosynthetic light harvesting can be down-regulated by nonphotochemical quenching (NPQ). A major component of NPQ is qE (energy-dependent nonphotochemical quenching), which allows dissipation of light energy as heat. Photodamage peaks in the UV-B part of the spectrum, but whether and how UV-B induces qE are unknown. Plants are responsive to UV-B via the UVR8 photoreceptor. Here, we report in the green alga Chlamydomonas reinhardtii that UVR8 induces accumulation of specific members of the light-harvesting complex (LHC) superfamily that contribute to qE, in particular LHC Stress-Related 1 (LHCSR1) and Photosystem II Subunit S (PSBS). The capacity for qE is strongly induced by UV-B, although the patterns of qE-related proteins accumulating in response to UV-B or to high light are clearly different. The competence for qE induced by acclimation to UV-B markedly contributes to photoprotection upon subsequent exposure to high light. Our study reveals an anterograde link between photoreceptor-mediated signaling in the nucleocytosolic compartment and the photoprotective regulation of photosynthetic activity in the chloroplast.
authors.affiliation: Department of Botany and Plant Biology, Sciences III, University of Geneva, Geneva CH-1211, Switzerland.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Allorent
authors.affiliation: Department of Botany and Plant Biology, Sciences III, University of Geneva, Geneva CH-1211, Switzerland.
authors.forename: Linnka
authors.initials: L
authors.lastname: Lefebvre-Legendre
authors.affiliation: Department of Botany and Plant Biology, Sciences III, University of Geneva, Geneva CH-1211, Switzerland.
authors.forename: Richard
authors.initials: R
authors.lastname: Chappuis
authors.affiliation: Laboratoire de Physiologie Cellulaire et Végétale, Commissariat à l'Énergie Atomique et aux Énergies Alternatives/Centre National de la Recherche Scientifique/Université Grenoble Alpes/Institut National de la Recherche Agronomique, 38054 Grenoble, France.
authors.forename: Marcel
authors.initials: M
authors.lastname: Kuntz
authors.affiliation: Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720.|Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720.
authors.forename: Thuy B
authors.initials: TB
authors.lastname: Truong
authors.affiliation: Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720.|Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720.
authors.forename: Krishna K
authors.initials: KK
authors.lastname: Niyogi
authors.affiliation: Department of Botany and Plant Biology, Sciences III, University of Geneva, Geneva CH-1211, Switzerland; roman.ulm@unige.ch michel.goldschmidt-clermont@unige.ch.|Institute of Genetics and Genomics of Geneva, University of Geneva, Geneva CH-1211, Switzerland.
authors.forename: Roman
authors.identifier: 0000-0001-8014-7392
authors.initials: R
authors.lastname: Ulm
authors.affiliation: Department of Botany and Plant Biology, Sciences III, University of Geneva, Geneva CH-1211, Switzerland; roman.ulm@unige.ch michel.goldschmidt-clermont@unige.ch.|Institute of Genetics and Genomics of Geneva, University of Geneva, Geneva CH-1211, Switzerland.
authors.forename: Michel
authors.initials: M
authors.lastname: Goldschmidt-Clermont
mesh_terms: D017360:Arabidopsis / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000378:metabolism; D016825:Chlamydomonas reinhardtii / Q000378:metabolism* / Q000502:physiology*; D002734:Chlorophyll / Q000378:metabolism; D005453:Fluorescence; D018506:Gene Expression Regulation, Plant; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000502:physiology*; D010766:Phosphorylation; D017785:Photons; D010788:Photosynthesis / Q000502:physiology*; D045332:Photosystem II Protein Complex / Q000502:physiology; D055503:Protein Multimerization; D015398:Signal Transduction; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D029681:Arabidopsis Proteins; D045342:Light-Harvesting Protein Complexes; D045332:Photosystem II Protein Complex; D002734:Chlorophyll; C471983:AT2G32950 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases
keywords: LHCSR1; PSBS; UV-B photoreceptor; nonphotochemical quenching; photoprotection