title: Activation of cyclic electron flow by hydrogen peroxide in vivo.
abstract: 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. We propose that H2O2 is a missing link between environmental stress, metabolism, and redox regulation of CEF in higher plants.
authors: Plant Research Laboratory and Departments of Plant Biology and.
authors: Deserah D
authors: DD
authors: Strand
authors: School of Molecular Biosciences and Institute for Biological Chemistry, Washington State University, Pullman, WA 99164; and.
authors: Aaron K
authors: AK
authors: Livingston
authors: Plant Research Laboratory and.
authors: Mio
authors: M
authors: Satoh-Cruz
authors: Plant Research Laboratory and Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824;
authors: John E
authors: JE
authors: Froehlich
authors: Institute of Developmental and Molecular Biology of Plants, Plant Molecular Physiology and Biotechnology Group, Heinrich-Heine-Universität, Cluster of Excellence on Plant Sciences (CEPLAS), 40225 Düsseldorf, Germany.
authors: Veronica G
authors: VG
authors: Maurino
authors: Plant Research Laboratory and Departments of Plant Biology and Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824; kramerd8@msu.edu.
authors: David M
authors: DM
authors: Kramer
mesh_terms: D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002736:Chloroplasts / Q000235:genetics / Q000378:metabolism*; D004579:Electron Transport / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D016877:Oxidants / Q000494:pharmacology*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics / Q000378:metabolism; D045331:Photosystem I Protein Complex / Q000235:genetics / Q000378:metabolism; D011808:Quinone Reductases / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological / Q000187:drug effects* / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D008565:Membrane Proteins; D016877:Oxidants; C465062:PGR5 protein, Arabidopsis; C527375:PGRL1 protein, Arabidopsis; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D006861:Hydrogen Peroxide; D000429:Alcohol Oxidoreductases; C020821:glycollate oxidase; C087049:NADPH - phenanthrenequinone oxidoreductase; D011808:Quinone Reductases
keywords: cyclic electron flow; hydrogen peroxide; photosynthesis; reactive oxygen species; stress