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Title: Activation of cyclic electron flow by hydrogen peroxide in vivo

Cyclic electron flow (CEF) around photosystem I is thought to balance the ATP/NADPH energy budget of photosynthesis, requiring that its rate be finely regulated. The mechanisms of this regulation are not well understood. We observed that mutants that exhibited constitutively high rates of CEF also showed elevated production of H2O2. We thus tested the hypothesis that CEF can be activated by H2O2 in vivo. CEF was strongly increased by H2O2 both by infiltration or in situ production by chloroplast-localized glycolate oxidase, implying that H2O2 can activate CEF either directly by redox modulation of key enzymes, or indirectly by affecting other photosynthetic processes. CEF appeared with a half time of about 20 min after exposure to H2O2, suggesting activation of previously expressed CEF-related machinery. H2O2-dependent CEF was not sensitive to antimycin A or loss of PGR5, indicating that increased CEF probably does not involve the PGR5-PGRL1 associated pathway. In contrast, the rise in CEF was not observed in a mutant deficient in the chloroplast NADPH:PQ reductase (NDH), supporting the involvement of this complex in CEF activated by H2O2. In conclusion, we propose that H2O2 is a missing link between environmental stress, metabolism, and redox regulation of CEF in higher plants.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6]
  1. Michigan State Univ., East Lansing, MI (United States). Dept. of Plant Biology. Plant Research Lab.
  2. Washington State Univ., Pullman, WA (United States). School of Molecular Biosciences. Inst. for Biological Chemistry
  3. Michigan State Univ., East Lansing, MI (United States). Plant Research Lab.
  4. Michigan State Univ., East Lansing, MI (United States). Dept. of Biochemistry and Molecular Biology. Plant Research Lab.
  5. Heinrich Heine Univ., Dusseldorf (Germany). Cluster of Excellence on Plant Sciences (CEPLAS). Inst. of Developmental and Molecular Biology of Plants. Plant Molecular Physiology and Biotechnology Group
  6. Michigan State Univ., East Lansing, MI (United States). Dept. of Plant Biology. Dept. of Biochemistry and Molecular Biology. Plant Research Lab.
Publication Date:
Grant/Contract Number:
FG02-04ER15559; FG02-11ER16220; MA2379/11-1
Type:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 112; Journal Issue: 17; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Washington State Univ., Pullman, WA (United States); Michigan State Univ., East Lansing, MI (United States); Heinrich Heine Univ., Dusseldorf (Germany)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); German Research Foundation (DFG)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; cyclic electron flow; photosynthesis; reactive oxygen species; stress; hydrogen peroxide
OSTI Identifier:
1235192
Alternate Identifier(s):
OSTI ID: 1348375