Cyclic electron transport through photosystem I

Munekage, Yuri; Shikanai, Toshiharu

doi:10.5511/plantbiotechnology.22.361

Cited by 45 publications

(24 citation statements)

References 69 publications

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“…The electrons originating from the reduced ferredoxin connected with PSI can interact with several ferredoxindependent enzymes during the assimilation of inorganic nitrogen, sulphur, N 2 -fixation, and the regulation of the CO 2 -assimilation cycle (Fukuyama, 2004). Considering the cyclic flow of electrons, which depends only on the photochemical reactions of PSI (Munekage and Shinakai, 2005), the electrons are recycled from ferredoxin to plastoquinone, with concomitant ATP production (Shikanai, 2007). This electron flux may have been intensified in the plants receiving a high Fe concentration (9.00 mM), in detriment to the non-cyclic flow.…”

Section: Discussionmentioning

confidence: 99%

Excess iron-induced changes in the photosynthetic characteristics of sweet potato

Adamski

Peters

Danieloski³

et al. 2011

Journal of Plant Physiology

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Section: Discussionmentioning

confidence: 99%

Excess iron-induced changes in the photosynthetic characteristics of sweet potato

Adamski

Peters

Danieloski³

et al. 2011

Journal of Plant Physiology

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“…The mutants were isolated by genetic screening focusing on a defect in photosynthetic electron transport. The light reactions of photosynthesis are a process for converting the light energy of the sun into chemical energy in the form of NADPH and ATP, and consist of two types of electron transport, the linear and cyclic around photosystem I (PSI), which occur in the chloroplast (reviewed in [50]). In higher plants, the PSI cyclic electron transport consists of PGR5-and NDH [NAD(P)H dehydrogenase]-dependent pathways.…”

Section: Identification Of An Rna Editing Mutant In Arabidopsismentioning

confidence: 99%

RNA editing in plant organelles: machinery, physiological function and evolution

Shikanai

2006

Cell. Mol. Life Sci.

238

186

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In plants, RNA editing is a process for converting a specific nucleotide of RNA from C to U and less frequently from U to C in mitochondria and plastids. To specify the site of editing, the cis-element adjacent to the editing site functions as a binding site for the trans-acting factor. Genetic approaches using Arabidopsis thaliana have clarified that a member of the protein family with pentatricopeptide repeat (PPR) motifs is essential for RNA editing to generate a translational initiation codon of the chloroplast ndhD gene. The PPR motif is a highly degenerate unit of 35 amino acids and appears as tandem repeats in proteins that are involved in RNA maturation steps in mitochondria and plastids. The Arabidopsis genome encodes approximately 450 members of the PPR family, some of which possibly function as trans-acting factors binding the cis-elements of the RNA editing sites to facilitate access of an unidentified RNA editing enzyme. Based on this breakthrough in the research on plant RNA editing, I would like to discuss the possible steps of co-evolution of RNA editing events and PPR proteins.

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“…For recent reviews, see (Joliot and Joliot 2006;Munekage and Shikanai 2006). The first one involves the participation of the enzyme ferredoxin-quinone oxidoreductase (FQR) that utilizes ferredoxin photoreduced at PSI stromal openings to feed electrons into Cyt b 6 /f and then to reduce plastoquinone (PQ) (Munekage et al 2002).…”

Section: Introductionmentioning

confidence: 97%

Changes in the mode of electron flow to photosystem I following chilling-induced photoinhibition in a C3 plant, Cucumis sativus L.

et al. 2007

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This study provides evidence for enhanced electron flow from the stromal compartment of the photosynthetic membranes to P700+ via the cytochrome b6/f complex (Cyt b6/f) in leaves of Cucumis sativus L. submitted to chilling-induced photoinhibition. The above is deduced from the P700 oxidation-reduction kinetics studied in the absence of linear electron transport from water to NADP+, cyclic electron transfer mediated through the Q-cycle of Cyt b6/f and charge recombination in photosystem I (PSI). The segregation of these pathways for P700+ rereduction were achieved by the use of a 50-ms multiple turnover white flash or a strong pulse of white or far-red illumination together with inhibitors. In cucumber leaves, chilling-induced photoinhibition resulted in approximately 20% loss of photo-oxidizible P700. The measurement of P700+ was greatly limited by the turnover of cyclic processes in the absence of the linear mode of electron transport as electrons were rapidly transferred to the smaller pool of P700+. The above is explained by integrating the recent model of the cyclic electron flow in C3 plants based on the Cyt b6/f structural data [Joliot and Joliot (2006) Biochim Biophys Acta 1757:362-368] and a photoprotective function elicited by a low NADP+/NAD(P)H ratio [Rajagopal et al. (2003) Biochemistry 42:11839-11845]. Over-reduction of the photosynthetic apparatus results in the accumulation of NAD(P)H in vivo to prevent NADP+-induced reversible conformational changes in PSI and its extensive damage. As the ferredoxin:NADP reductase is fully reduced under these conditions, even in the absence of PSII electron transport, the reduced ferredoxin generated during illumination binds at the stromal openings in the Cyt b6/f complex and activates cyclic electron flow. On the other hand, the excess electrons from the NAD(P)H pool are routed via the Ndh complex in a slow process to maintain moderate reduction of the plastoquinone pool and redox poise required for the operation of ferredoxin:plastoquinone reductase mediated cyclic flow.

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Cyclic electron transport through photosystem I

Cited by 45 publications

References 69 publications

Excess iron-induced changes in the photosynthetic characteristics of sweet potato

Excess iron-induced changes in the photosynthetic characteristics of sweet potato

RNA editing in plant organelles: machinery, physiological function and evolution

Changes in the mode of electron flow to photosystem I following chilling-induced photoinhibition in a C3 plant, Cucumis sativus L.

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