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Title: UV-B photoreceptor-mediated protection of the photosynthetic machinery in Chlamydomonas reinhardtii

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 in this paper, 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.
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  1. Univ. of Geneva (Switzerland). Dept. of Botany and Plant Biology, Sciences III
  2. Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA), Grenoble (France). Laboratoire de Physiologie Cellulaire et Vegetale
  3. Univ. of California, Berkeley, CA (United States). Howard Hughes Medical Inst., Dept. of Plant and Microbial Biology; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Molecular Biophysics and Integrated Bioimaging Division
  4. Univ. of Geneva (Switzerland). Dept. of Botany and Plant Biology, Sciences III; Univ. of Geneva (Switzerland). Inst. of Genetics and Genomics of Geneva
Publication Date:
Grant/Contract Number:
AC02-05CH11231; GBMF3070; 31003A_153475; 31003A_146300
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 113; Journal Issue: 51; Journal ID: ISSN 0027-8424
National Academy of Sciences, Washington, DC (United States)
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); European Union (EU); Gordon and Betty Moore Foundation; Swiss National Science Foundation (SNSF)
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 60 APPLIED LIFE SCIENCES; photoprotection; nonphotochemical quenching; UV-B photoreceptor; PSBS; LHCSR1
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1411563