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Kobayashi R, Yamamoto H, Ishibashi K, Shikanai T. Critical role of cyclic electron transport around photosystem I in the maintenance of photosystem I activity. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:2141-2153. [PMID: 38558422 DOI: 10.1111/tpj.16735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 03/05/2024] [Accepted: 03/14/2024] [Indexed: 04/04/2024]
Abstract
In angiosperms, cyclic electron transport around photosystem I (PSI) is mediated by two pathways that depend on the PROTON GRADIENT REGULATION 5 (PGR5) protein and the chloroplast NADH dehydrogenase-like (NDH) complex, respectively. In the Arabidopsis double mutants defective in both pathways, plant growth and photosynthesis are impaired. The pgr5-1 mutant used in the original study is a missense allele and accumulates low levels of PGR5 protein. In this study, we generated two knockout (KO) alleles, designated as pgr5-5 and pgr5-6, using the CRISPR-Cas9 technology. Although both KO alleles showed a severe reduction in P700 similar to the pgr5-1 allele, NPQ induction was less severely impaired in the KO alleles than in the pgr5-1 allele. In the pgr5-1 allele, the second mutation affecting NPQ size was mapped to ~21 cM south of the pgr5-1 locus. Overexpression of the pgr5-1 allele, encoding the glycine130-to-serine change, complemented the pgr5-5 phenotype, suggesting that the pgr5-1 mutation destabilizes PGR5 but that the mutant protein retains partial functionality. Using two KO alleles, we created the double mutants with two chlororespiratory reduction (crr) mutants defective in the NDH complex. The growth of the double mutants was notably impaired. In the double mutant seedlings that survived on the medium containing sucrose, PSI activity evaluated by the P700 oxidation was severely impaired, whereas PSII activity was only mildly impaired. Cyclic electron transport around PSI is required to maintain PSI activity.
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Affiliation(s)
- Ryouhei Kobayashi
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Kota Ishibashi
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
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2
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Shikanai T. Molecular Genetic Dissection of the Regulatory Network of Proton Motive Force in Chloroplasts. PLANT & CELL PHYSIOLOGY 2024; 65:537-550. [PMID: 38150384 DOI: 10.1093/pcp/pcad157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 11/27/2023] [Accepted: 12/08/2023] [Indexed: 12/29/2023]
Abstract
The proton motive force (pmf) generated across the thylakoid membrane rotates the Fo-ring of ATP synthase in chloroplasts. The pmf comprises two components: membrane potential (∆Ψ) and proton concentration gradient (∆pH). Acidification of the thylakoid lumen resulting from ∆pH downregulates electron transport in the cytochrome b6f complex. This process, known as photosynthetic control, is crucial for protecting photosystem I (PSI) from photodamage in response to fluctuating light. To optimize the balance between efficient photosynthesis and photoprotection, it is necessary to regulate pmf. Cyclic electron transport around PSI and pseudo-cyclic electron transport involving flavodiiron proteins contribute to the modulation of pmf magnitude. By manipulating the ratio between the two components of pmf, it is possible to modify the extent of photosynthetic control without affecting the pmf size. This adjustment can be achieved by regulating the movement of ions (such as K+ and Cl-) across the thylakoid membrane. Since ATP synthase is the primary consumer of pmf in chloroplasts, its activity must be precisely regulated to accommodate other mechanisms involved in pmf optimization. Although fragments of information about each regulatory process have been accumulated, a comprehensive understanding of their interactions is lacking. Here, I summarize current knowledge of the network for pmf regulation, mainly based on genetic studies.
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Affiliation(s)
- Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan
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3
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Penzler JF, Naranjo B, Walz S, Marino G, Kleine T, Leister D. A pgr5 suppressor screen uncovers two distinct suppression mechanisms and links cytochrome b6f complex stability to PGR5. THE PLANT CELL 2024:koae098. [PMID: 38781425 DOI: 10.1093/plcell/koae098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 03/13/2024] [Indexed: 05/25/2024]
Abstract
PROTON GRADIENT REGULATION5 (PGR5) is thought to promote cyclic electron flow, and its deficiency impairs photosynthetic control and increases photosensitivity of photosystem (PS) I, leading to seedling lethality under fluctuating light (FL). By screening for Arabidopsis (Arabidopsis thaliana) suppressor mutations that rescue the seedling lethality of pgr5 plants under FL, we identified a portfolio of mutations in 12 different genes. These mutations affect either PSII function, cytochrome b6f (cyt b6f) assembly, plastocyanin (PC) accumulation, the CHLOROPLAST FRUCTOSE-1,6-BISPHOSPHATASE1 (cFBP1), or its negative regulator ATYPICAL CYS HIS-RICH THIOREDOXIN2 (ACHT2). The characterization of the mutants indicates that the recovery of viability can in most cases be explained by the restoration of PSI donor side limitation, which is caused by reduced electron flow to PSI due to defects in PSII, cyt b6f, or PC. Inactivation of cFBP1 or its negative regulator ACHT2 results in increased levels of the NADH dehydrogenase-like complex. This increased activity may be responsible for suppressing the pgr5 phenotype under FL conditions. Plants that lack both PGR5 and DE-ETIOLATION-INDUCED PROTEIN1 (DEIP1)/NEW TINY ALBINO1 (NTA1), previously thought to be essential for cyt b6f assembly, are viable and accumulate cyt b6f. We suggest that PGR5 can have a negative effect on the cyt b6f complex and that DEIP1/NTA1 can ameliorate this negative effect.
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Affiliation(s)
- Jan-Ferdinand Penzler
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried D-82152, Germany
| | - Belén Naranjo
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried D-82152, Germany
| | - Sabrina Walz
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried D-82152, Germany
| | - Giada Marino
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried D-82152, Germany
| | - Tatjana Kleine
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried D-82152, Germany
| | - Dario Leister
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried D-82152, Germany
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4
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Lan Y, Chen Q, Mi H. NdhS interacts with cytochrome b 6 f to form a complex in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 116:706-716. [PMID: 37493543 DOI: 10.1111/tpj.16398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 06/27/2023] [Accepted: 07/05/2023] [Indexed: 07/27/2023]
Abstract
Cyclic electron transport (CET) around photosystem I (PSI) is crucial for photosynthesis to perform photoprotection and sustain the balance of ATP and NADPH. However, the critical component of CET, cyt b6 f complex (cyt b6 f), functions in CET has yet to be understood entirely. In this study, we found that NdhS, a subunit of NADPH dehydrogenase-like (NDH) complex, interacted with cyt b6 f to form a complex in Arabidopsis. This interaction depended on the N-terminal extension of NdhS, which was conserved in eukaryotic plants but defective in prokaryotic algae. The migration of NdhS was much more in cyt b6 f than in PSI-NDH super-complex. Based on these results, we suggested that NdhS and NADP+ oxidoreductase provide a docking domain for the mobile electron carrier ferredoxin to transfer electrons to the plastoquinone pool via cyt b6 f in eukaryotic photosynthesis.
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Affiliation(s)
- Yixin Lan
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences / Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai, 200032, P.R. China
| | - Qi Chen
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences / Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai, 200032, P.R. China
| | - Hualing Mi
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences / Institute of Plant Physiology and Ecology, 300 Fenglin Road, Shanghai, 200032, P.R. China
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5
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Yamamoto H, Cheuk A, Shearman J, Nixon PJ, Meier T, Shikanai T. Impact of engineering the ATP synthase rotor ring on photosynthesis in tobacco chloroplasts. PLANT PHYSIOLOGY 2023; 192:1221-1233. [PMID: 36703219 PMCID: PMC10231360 DOI: 10.1093/plphys/kiad043] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 01/05/2023] [Accepted: 01/06/2023] [Indexed: 06/01/2023]
Abstract
The chloroplast ATP synthase produces the ATP needed for photosynthesis and plant growth. The trans-membrane flow of protons through the ATP synthase rotates an oligomeric assembly of c subunits, the c-ring. The ion-to-ATP ratio in rotary F1F0-ATP synthases is defined by the number of c-subunits in the rotor c-ring. Engineering the c-ring stoichiometry is, therefore, a possible route to manipulate ATP synthesis by the ATP synthase and hence photosynthetic efficiency in plants. Here, we describe the construction of a tobacco (Nicotiana tabacum) chloroplast atpH (chloroplastic ATP synthase subunit c gene) mutant in which the c-ring stoichiometry was increased from 14 to 15 c-subunits. Although the abundance of the ATP synthase was decreased to 25% of wild-type (WT) levels, the mutant lines grew as well as WT plants and photosynthetic electron transport remained unaffected. To synthesize the necessary ATP for growth, we found that the contribution of the membrane potential to the proton motive force was enhanced to ensure a higher proton flux via the c15-ring without unwanted low pH-induced feedback inhibition of electron transport. Our work opens avenues to manipulate plant ion-to-ATP ratios with potentially beneficial consequences for photosynthesis.
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Affiliation(s)
- Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Anthony Cheuk
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington Campus, London SW7 2AZ, UK
| | - Julia Shearman
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington Campus, London SW7 2AZ, UK
| | - Peter J Nixon
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington Campus, London SW7 2AZ, UK
| | - Thomas Meier
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington Campus, London SW7 2AZ, UK
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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6
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Zhou Q, Yamamoto H, Shikanai T. Distinct contribution of two cyclic electron transport pathways to P700 oxidation. PLANT PHYSIOLOGY 2023; 192:326-341. [PMID: 36477622 PMCID: PMC10152692 DOI: 10.1093/plphys/kiac557] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 11/09/2022] [Accepted: 11/10/2022] [Indexed: 05/03/2023]
Abstract
Cyclic electron transport (CET) around Photosystem I (PSI) acidifies the thylakoid lumen and downregulates electron transport at the cytochrome b6f complex. This photosynthetic control is essential for oxidizing special pair chlorophylls (P700) of PSI for PSI photoprotection. In addition, CET depending on the PROTON GRADIENT REGULATION 5 (PGR5) protein oxidizes P700 by moving a pool of electrons from the acceptor side of PSI to the plastoquinone pool. This model of the acceptor-side regulation was proposed on the basis of the phenotype of the Arabidopsis (Arabidopsis thaliana) pgr5-1 mutant expressing Chlamydomonas (Chlamydomonas reinhardtii) plastid terminal oxidase (CrPTOX2). In this study, we extended the research including the Arabidopsis chlororespiratory reduction 2-2 (crr2-2) mutant defective in another CET pathway depending on the chloroplast NADH dehydrogenase-like (NDH) complex. Although the introduction of CrPTOX2 did not complement the defect in the acceptor-side regulation by PGR5, the function of the NDH complex was complemented except for its reverse reaction during the induction of photosynthesis. We evaluated the impact of CrPTOX2 under fluctuating light intensity in the wild-type, pgr5-1 and crr2-2 backgrounds. In the high-light period, both PGR5- and NDH-dependent CET were involved in the induction of photosynthetic control, whereas PGR5-dependent CET preferentially contributed to the acceptor-side regulation. On the contrary, the NDH complex probably contributed to the acceptor-side regulation in the low-light period but not in the high-light period. We evaluated the sensitivity of PSI to fluctuating light and clarified that acceptor-side regulation was necessary for PSI photoprotection by oxidizing P700 under high light.
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Affiliation(s)
- Qi Zhou
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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7
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Zhou P, Zhang P, He M, Cao Y, Adeel M, Shakoor N, Jiang Y, Zhao W, Li Y, Li M, Azeem I, Jia L, Rui Y, Ma X, Lynch I. Iron-based nanomaterials reduce cadmium toxicity in rice (Oryza sativa L.) by modulating phytohormones, phytochelatin, cadmium transport genes and iron plaque formation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 320:121063. [PMID: 36639045 DOI: 10.1016/j.envpol.2023.121063] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 12/13/2022] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
Rice is known to accumulate cadmium (Cd) in its grains, causing a severe threat to billions of people worldwide. The possible phytotoxicity and mechanism of 50-200 mg/L hydroxyapatite NPs (nHA), iron oxide NPs (nFe2O3) or nano zero valent iron (nZVI) co-exposed with Cd (100 μM) in rice seedlings were investigated. Three types of nanoparticles significantly reduced the bioaccumulation of Cd in rice shoots by 16-63%, with nZVI showing the greatest effect, followed by nHA and nFe2O3. A decrease in Cd content in the roots was observed only in the nZVI treatment, with values ranging from 8 to 19%. Correspondingly, nZVI showed the best results in promoting plant growth, increasing rice plant height, shoot and root biomass by 13%, 29% and 42%. In vitro studies showed that nZVI reduced the content of Cd in the solution by 20-52% through adsorption, which might have contributed to the immobilization of Cd in root. Importantly, the nZVI treatment resulted in 267% more iron plaques on the root surface, which acted as a barrier to hinder the entry of Cd. Moreover, all three nanoparticles significantly reduced the oxidative stress induced by Cd by regulating phytohormones, phytochelatin, inorganic homeostasis and the expression of genes associated with Cd uptake and transport. Overall, this study elucidates for the first time the multiple complementing mechanisms for some nanoparticles to reduce Cd uptake and transport in rice and provides theoretical basis for applying nanoparticles for reducing Cd accumulation in edible plants.
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Affiliation(s)
- Pingfan Zhou
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Peng Zhang
- Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, China; School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Mengke He
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Yu Cao
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Muhammad Adeel
- BNU-HKUST Laboratory of Green Innovation, Advanced Institute of Natural Sciences, Beijing Normal University at Zhuhai, 519087, China
| | - Noman Shakoor
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Yaqi Jiang
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Weichen Zhao
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Yuanbo Li
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Mingshu Li
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Imran Azeem
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Like Jia
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Yukui Rui
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China.
| | - Xingmao Ma
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, TAMU 3136, College Station, TX, 77843, USA
| | - Iseult Lynch
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
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8
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Joliot P, Sellés J, Wollman FA, Verméglio A. High efficient cyclic electron flow and functional supercomplexes in Chlamydomonas cells. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148909. [PMID: 35952798 DOI: 10.1016/j.bbabio.2022.148909] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/02/2022] [Accepted: 08/03/2022] [Indexed: 06/15/2023]
Abstract
A very high rate for cyclic electron flow (CEF) around PSI (~180 s-1 or 210 s-1 in minimum medium or in the presence of a carbon source respectively) is measured in the presence of methyl viologen (MV) in intact cells of Chlamydomonas reinhardtii under anaerobic conditions. The observation of an efficient CEF in the presence of methyl viologen is in agreement with the previous results reports of Asada et al. in broken chloroplasts (Plant Cell Physiol. 31(4) (1990) 557-564). From the analysis of the P700 and PC absorbance changes, we propose that a confinement between 2 PC molecules, 1 PSI and 1 cytb6f corresponding to a functional supercomplex is responsible for these high rates of CEF. Supercomplex formation is also observed in the absence of methyl viologen, but with lower maximal CEF rate (about 100 s-1) suggesting that this compound facilitates the mediation of electron transfer from PSI acceptors to the stromal side of cytb6f. Further analysis of CEF in mutants of Chlamydomonas defective in state transitions shows the requirement of a kinase-driven transition to state 2 to establish this functional supercomplex configuration. However, a movement of the LHCII antennae is not involved in this process. We discuss the possible involvement of auxiliary proteins, among which is a small cytb6f-associated polypeptide, the PETO protein, which is one of the targets of the STT7 kinase.
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Affiliation(s)
- Pierre Joliot
- Laboratoire de Biologie du Chloroplaste et Perception de la Lumière Chez les Microalgues, Institut de Biologie Physico-Chimique, CNRS UMR 7141, Sorbonne Université, Paris, France.
| | - Julien Sellés
- Laboratoire de Biologie du Chloroplaste et Perception de la Lumière Chez les Microalgues, Institut de Biologie Physico-Chimique, CNRS UMR 7141, Sorbonne Université, Paris, France.
| | - Françis-André Wollman
- Laboratoire de Biologie du Chloroplaste et Perception de la Lumière Chez les Microalgues, Institut de Biologie Physico-Chimique, CNRS UMR 7141, Sorbonne Université, Paris, France
| | - André Verméglio
- Laboratoire de Biologie du Chloroplaste et Perception de la Lumière Chez les Microalgues, Institut de Biologie Physico-Chimique, CNRS UMR 7141, Sorbonne Université, Paris, France
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9
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Leister D, Marino G, Minagawa J, Dann M. An ancient function of PGR5 in iron delivery? TRENDS IN PLANT SCIENCE 2022; 27:971-980. [PMID: 35618596 DOI: 10.1016/j.tplants.2022.04.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 03/29/2022] [Accepted: 04/26/2022] [Indexed: 06/15/2023]
Abstract
In all phototrophic organisms, the photosynthetic apparatus must be protected from light-induced damage. One important mechanism that mitigates photodamage in plants is antimycin A (AA)-sensitive cyclic electron flow (CEF), the evolution of which remains largely obscure. Here we show that proton gradient regulation 5 (PGR5), a key protein involved in AA-sensitive CEF, displays intriguing commonalities - including sequence and structural features - with a group of ferritin-like proteins. We therefore propose that PGR5 may originally have been involved in prokaryotic iron mobilization and delivery, which facilitated a primordial type of CEF as a side effect. The abandonment of the bacterioferritin system during the transformation of cyanobacterial endosymbionts into chloroplasts might have allowed PGR5 to functionally specialize in CEF.
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Affiliation(s)
- Dario Leister
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
| | - Giada Marino
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
| | - Jun Minagawa
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | - Marcel Dann
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany; Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan.
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10
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Okegawa Y, Sakamoto W, Motohashi K. Functional division of f-type and m-type thioredoxins to regulate the Calvin cycle and cyclic electron transport around photosystem I. JOURNAL OF PLANT RESEARCH 2022; 135:543-553. [PMID: 35325335 DOI: 10.1007/s10265-022-01388-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 03/13/2022] [Indexed: 06/14/2023]
Abstract
Redox regulation of chloroplast proteins is necessary to adjust photosynthetic performance with changes in light. The thioredoxin (Trx) system plays a central role in this process. Chloroplast-localized classical Trx is a small redox-active protein that regulates many target proteins by reducing their disulfide bonds in a light-dependent manner. Arabidopsis thaliana mutants lacking f-type Trx (trx f1f2) or m-type Trx (trx m124-2) have been reported to show delayed reduction of Calvin cycle enzymes. As a result, the trx m124-2 mutant exhibits growth defects. Here, we characterized a quintuple mutant lacking both Trx f and Trx m to investigate the functional complementarity of Trx f and Trx m. The trx f1f2 m124-2 quintuple mutant was newly obtained by crossing, and is analyzed here for the first time. The growth defects of the trx m124-2 mutant were not enhanced by the lack of Trx f. In contrast, deficiencies of both Trxs additively suppressed the reduction of Calvin cycle enzymes, resulting in a further delay in the initiation of photosynthesis. Trx f appeared to be necessary for the rapid activation of the Calvin cycle during the early induction of photosynthesis. To perform effective photosynthesis, plants seem to use both Trxs in a coordinated manner to activate carbon fixation reactions. In contrast, the PROTON GRADIENT REGULATION 5 (PGR5)-dependent cyclic electron transport around photosystem I was regulated by Trx m, but not by Trx f. Lack of Trx f did not affect the activity and regulation of the PGR5-dependent pathway. Trx f may have a higher specificity for target proteins, whereas Trx m has a variety of target proteins to regulate overall photosynthesis and other metabolic reactions in the chloroplasts.
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Affiliation(s)
- Yuki Okegawa
- Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, 710-0046, Japan.
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo Motoyama, Kita-ku, Kyoto, 603-8047, Japan.
| | - Wataru Sakamoto
- Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, 710-0046, Japan
| | - Ken Motohashi
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo Motoyama, Kita-ku, Kyoto, 603-8047, Japan
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11
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Schwenkert S, Fernie AR, Geigenberger P, Leister D, Möhlmann T, Naranjo B, Neuhaus HE. Chloroplasts are key players to cope with light and temperature stress. TRENDS IN PLANT SCIENCE 2022; 27:577-587. [PMID: 35012879 DOI: 10.1016/j.tplants.2021.12.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 11/16/2021] [Accepted: 12/09/2021] [Indexed: 05/04/2023]
Abstract
Under natural environmental conditions, changes in light intensity and temperature are closely interwoven, and of all organelles, only chloroplasts react strongly upon alterations of these two parameters. We review increasing evidence indicating that changes in chloroplast metabolism are critical for the comprehensive cellular answer in a challenging environment. This cellular answer starts with rapid modifications of thylakoid-located processes, followed by modifications in the stroma and transport activities across the chloroplast envelope. We propose that the 'modulators' involved contribute to plant stress tolerance and that deciphering of their characteristics is essential to understand 'acclimation'. Especially in times of climatic changes, we must gain knowledge on physiological reactions that might become instrumental for directed breeding strategies aiming to develop stress-tolerant crop plants.
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12
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Zhou Q, Wang C, Yamamoto H, Shikanai T. PTOX-dependent safety valve does not oxidize P700 during photosynthetic induction in the Arabidopsis pgr5 mutant. PLANT PHYSIOLOGY 2022; 188:1264-1276. [PMID: 34792607 PMCID: PMC8825263 DOI: 10.1093/plphys/kiab541] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 10/15/2021] [Indexed: 05/19/2023]
Abstract
Plastid terminal oxidase (PTOX) accepts electrons from plastoquinol to reduce molecular oxygen to water. We introduced the gene encoding Chlamydomonas reinhardtii (Cr)PTOX2 into the Arabidopsis (Arabidopsis thaliana) wild-type (WT) and proton gradient regulation5 (pgr5) mutant defective in cyclic electron transport around photosystem I (PSI). The accumulation of CrPTOX2 only mildly affected photosynthetic electron transport in the WT background during steady-state photosynthesis but partly complemented the induction of nonphotochemical quenching (NPQ) in the pgr5 background. During the induction of photosynthesis by actinic light (AL) of 130 µmol photons m-2 s-1, the high level of PSII yield (Y(II)) was induced immediately after the onset of AL in WT plants accumulating CrPTOX2. NPQ was more rapidly induced in the transgenic plants than in WT plants. P700 was also oxidized immediately after the onset of AL. Although CrPTOX2 does not directly induce a proton concentration gradient (ΔpH) across the thylakoid membrane, the coupled reaction of PSII generated ΔpH to induce NPQ and the downregulation of the cytochrome b6f complex. Rapid induction of Y(II) and NPQ was also observed in the pgr5 plants accumulating CrPTOX2. In contrast to the WT background, P700 was not oxidized in the pgr5 background. Although the thylakoid lumen was acidified by CrPTOX2, PGR5 was essential for oxidizing P700. In addition to acidification of the thylakoid lumen to downregulate the cytochrome b6f complex (donor-side regulation), PGR5 may be required for draining electrons from PSI by transferring them to the plastoquinone pool. We propose a reevaluation of the contribution of this acceptor-side regulation by PGR5 in the photoprotection of PSI.
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Affiliation(s)
- Qi Zhou
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Caijuan Wang
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
- Author for communication:
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13
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Okegawa Y, Tsuda N, Sakamoto W, Motohashi K. Maintaining the Chloroplast Redox Balance through the PGR5-Dependent Pathway and the Trx System Is Required for Light-Dependent Activation of Photosynthetic Reactions. PLANT & CELL PHYSIOLOGY 2022; 63:92-103. [PMID: 34623443 DOI: 10.1093/pcp/pcab148] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/26/2021] [Accepted: 10/08/2021] [Indexed: 06/13/2023]
Abstract
Light-dependent activation of chloroplast enzymes is required for the rapid induction of photosynthesis after a shift from dark to light. The thioredoxin (Trx) system plays a central role in this process. In chloroplasts, the Trx system consists of two pathways: the ferredoxin (Fd)/Trx pathway and the nicotinamide adenine dinucleotide phosphate (NADPH)-Trx reductase C (NTRC) pathway. In Arabidopsis (Arabidopsis thaliana) mutants defective in either pathway, the photoreduction of thiol enzymes was impaired, resulting in decreased carbon fixation. The close relationship between the Fd/Trx pathway and proton gradient regulation 5 (PGR5)-dependent photosystem I cyclic electron transport (PSI CET) in the induction of photosynthesis was recently elucidated. However, how the PGR5-dependent pathway is involved in the NTRC pathway is unclear, although NTRC has been suggested to physically interact with PGR5. In this study, we analyzed Arabidopsis mutants lacking either the PGR5 or the chloroplast NADH dehydrogenase-like complex (NDH)-dependent PSI CET pathway in the ntrc mutant background. The ntrc pgr5 double mutant suppressed both the growth defects and the high non-photochemical quenching phenotype of the ntrc mutant when grown under long-day conditions. By contrast, the inactivation of NDH activity with the chlororespiratory reduction 2-2 mutant failed to suppress either phenotype. We discovered that the phenotypic rescue of ntrc by pgr5 is caused by the partial restoration of Trx-dependent reduction of thiol enzymes. These results suggest that electron partitioning to the PGR5-dependent pathway and the Trx system needs to be properly regulated for the activation of the Calvin-Benson-Bassham cycle enzymes during the induction of photosynthesis.
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Affiliation(s)
- Yuki Okegawa
- Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, Okayama, 710-0046 Japan
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo Motoyama, Kita-ku, Kyoto, 603-8047 Japan
| | - Natsuki Tsuda
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo Motoyama, Kita-ku, Kyoto, 603-8047 Japan
| | - Wataru Sakamoto
- Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, Okayama, 710-0046 Japan
| | - Ken Motohashi
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo Motoyama, Kita-ku, Kyoto, 603-8047 Japan
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14
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Electron transfer via cytochrome b6f complex displays sensitivity to Antimycin A upon STT7 kinase activation. Biochem J 2022; 479:111-127. [PMID: 34981811 DOI: 10.1042/bcj20210802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/23/2021] [Accepted: 01/04/2022] [Indexed: 11/17/2022]
Abstract
The cytochrome b6f complex (b6f) has been initially considered as the ferredoxin-plastoquinone reductase (FQR) during cyclic electron flow (CEF) with photosystem I that is inhibited by antimycin A (AA). The binding of AA to the b6f Qi-site is aggravated by heme-ci, which challenged the FQR function of b6f during CEF. Alternative models suggest that PROTON GRADIENT REGULATION5 (PGR5) is involved in a b6f-independent, AA-sensitive FQR. Here, we show in Chlamydomonas reinhardtii that the b6f is conditionally inhibited by AA in vivo and that the inhibition did not require PGR5. Instead, activation of the STT7 kinase upon anaerobic treatment induced the AA sensitivity of b6f which was absent in stt7-1. However, a lock in State 2 due to persisting phosphorylation in the phosphatase double mutant pph1;pbcp did not increase AA sensitivity of electron transfer. The latter required a redox poise, supporting the view that state transitions and CEF are not coercively coupled. This suggests that the b6f-interacting kinase is required for structure-function modulation of the Qi-site under CEF favoring conditions. We propose that PGR5 and STT7 independently sustain AA-sensitive FQR activity of the b6f. Accordingly, PGR5-mediated electron injection into an STT7-modulated Qi-site drives a Mitchellian Q cycle in CEF conditions.
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15
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Johnson JE, Field CB, Berry JA. The limiting factors and regulatory processes that control the environmental responses of C 3, C 3-C 4 intermediate, and C 4 photosynthesis. Oecologia 2021; 197:841-866. [PMID: 34714387 PMCID: PMC8591018 DOI: 10.1007/s00442-021-05062-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 10/07/2021] [Indexed: 11/28/2022]
Abstract
Here, we describe a model of C3, C3-C4 intermediate, and C4 photosynthesis that is designed to facilitate quantitative analysis of physiological measurements. The model relates the factors limiting electron transport and carbon metabolism, the regulatory processes that coordinate these metabolic domains, and the responses to light, carbon dioxide, and temperature. It has three unique features. First, mechanistic expressions describe how the cytochrome b6f complex controls electron transport in mesophyll and bundle sheath chloroplasts. Second, the coupling between the mesophyll and bundle sheath expressions represents how feedback regulation of Cyt b6f coordinates electron transport and carbon metabolism. Third, the temperature sensitivity of Cyt b6f is differentiated from that of the coupling between NADPH, Fd, and ATP production. Using this model, we present simulations demonstrating that the light dependence of the carbon dioxide compensation point in C3-C4 leaves can be explained by co-occurrence of light saturation in the mesophyll and light limitation in the bundle sheath. We also present inversions demonstrating that population-level variation in the carbon dioxide compensation point in a Type I C3-C4 plant, Flaveria chloraefolia, can be explained by variable allocation of photosynthetic capacity to the bundle sheath. These results suggest that Type I C3-C4 intermediate plants adjust pigment and protein distributions to optimize the glycine shuttle under different light and temperature regimes, and that the malate and aspartate shuttles may have originally functioned to smooth out the energy supply and demand associated with the glycine shuttle. This model has a wide range of potential applications to physiological, ecological, and evolutionary questions.
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Affiliation(s)
- Jennifer E Johnson
- Department of Global Ecology, Carnegie Institution for Science, 260 Panama Street, Stanford, CA, 94305, USA.
| | - Christopher B Field
- Department of Global Ecology, Carnegie Institution for Science, 260 Panama Street, Stanford, CA, 94305, USA.,Stanford Woods Institute for the Environment, Stanford University, 473 Via Ortega, Stanford, CA, 94305, USA
| | - Joseph A Berry
- Department of Global Ecology, Carnegie Institution for Science, 260 Panama Street, Stanford, CA, 94305, USA
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16
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Haber Z, Lampl N, Meyer AJ, Zelinger E, Hipsch M, Rosenwasser S. Resolving diurnal dynamics of the chloroplastic glutathione redox state in Arabidopsis reveals its photosynthetically derived oxidation. THE PLANT CELL 2021; 33:1828-1844. [PMID: 33624811 PMCID: PMC8254480 DOI: 10.1093/plcell/koab068] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 02/23/2021] [Indexed: 05/05/2023]
Abstract
Plants are subjected to fluctuations in light intensity, and this might cause unbalanced photosynthetic electron fluxes and overproduction of reactive oxygen species (ROS). Electrons needed for ROS detoxification are drawn, at least partially, from the cellular glutathione (GSH) pool via the ascorbate-glutathione cycle. Here, we explore the dynamics of the chloroplastic glutathione redox potential (chl-EGSH) using high-temporal-resolution monitoring of Arabidopsis (Arabidopsis thaliana) lines expressing the reduction-oxidation sensitive green fluorescent protein 2 (roGFP2) in chloroplasts. This was carried out over several days under dynamic environmental conditions and in correlation with PSII operating efficiency. Peaks in chl-EGSH oxidation during dark-to-light and light-to-dark transitions were observed. Increasing light intensities triggered a binary oxidation response, with a threshold around the light saturating point, suggesting two regulated oxidative states of the chl-EGSH. These patterns were not affected in npq1 plants, which are impaired in non-photochemical quenching. Oscillations between the two oxidation states were observed under fluctuating light in WT and npq1 plants, but not in pgr5 plants, suggesting a role for PSI photoinhibition in regulating the chl-EGSH dynamics. Remarkably, pgr5 plants showed an increase in chl-EGSH oxidation during the nights following light stresses, linking daytime photoinhibition and nighttime GSH metabolism. This work provides a systematic view of the dynamics of the in vivo chloroplastic glutathione redox state during varying light conditions.
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Affiliation(s)
- Zechariah Haber
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture,
The Hebrew University of Jerusalem, Rehovot 7610000, Israel
| | - Nardy Lampl
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture,
The Hebrew University of Jerusalem, Rehovot 7610000, Israel
| | - Andreas J Meyer
- Institute of Crop Science and Resource Conservation (INRES), Rheinische
Friedrich–Wilhelms Universität Bonn, Friedrich-Ebert-Allee 144, D-53113
Bonn, Germany
| | - Einat Zelinger
- The Interdepartmental Equipment Unit, The Robert H. Smith Faculty of
Agriculture, Food and Environment, The Hebrew University of Jerusalem,
Rehovot 7610001, Israel
| | - Matanel Hipsch
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture,
The Hebrew University of Jerusalem, Rehovot 7610000, Israel
| | - Shilo Rosenwasser
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture,
The Hebrew University of Jerusalem, Rehovot 7610000, Israel
- Author for correspondence:
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17
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Wu X, Wu J, Wang Y, He M, He M, Liu W, Shu S, Sun J, Guo S. The key cyclic electron flow protein PGR5 associates with cytochrome b 6f, and its function is partially influenced by the LHCII state transition. HORTICULTURE RESEARCH 2021; 8:55. [PMID: 33664242 PMCID: PMC7933433 DOI: 10.1038/s41438-021-00460-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 10/30/2020] [Accepted: 11/20/2020] [Indexed: 05/08/2023]
Abstract
In plants and algae, PGR5-dependent cyclic electron flow (CEF) is an important regulator of acclimation to fluctuating environments, but how PGR5 participates in CEF is unclear. In this work, we analyzed two PGR5s in cucumber (Cucumis sativus L.) under different conditions and found that CsPGR5a played the dominant role in PGR5-dependent CEF. The results of yeast two-hybrid, biomolecular fluorescence complementation (BiFC), blue native PAGE, and coimmunoprecipitation (CoIP) assays showed that PGR5a interacted with PetC, Lhcb3, and PsaH. Furthermore, the intensity of the interactions was dynamic during state transitions, and the abundance of PGR5 attached to cyt b6f decreased during the transition from state 1 to state 2, which revealed that the function of PGR5a is related to the state transition. We proposed that PGR5 is a small mobile protein that functions when attached to protein complexes.
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Affiliation(s)
- Xinyi Wu
- College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jianqiang Wu
- College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yu Wang
- College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Meiwen He
- College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Mingming He
- College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Weikang Liu
- College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Sheng Shu
- College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
- Nanjing Agricultural University (Suqian) Academy of Protected Horticulture, Jiangsu, Suqian, 223800, China
| | - Jin Sun
- College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
- Nanjing Agricultural University (Suqian) Academy of Protected Horticulture, Jiangsu, Suqian, 223800, China.
| | - Shirong Guo
- College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
- Nanjing Agricultural University (Suqian) Academy of Protected Horticulture, Jiangsu, Suqian, 223800, China.
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18
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Sarewicz M, Pintscher S, Pietras R, Borek A, Bujnowicz Ł, Hanke G, Cramer WA, Finazzi G, Osyczka A. Catalytic Reactions and Energy Conservation in the Cytochrome bc1 and b6f Complexes of Energy-Transducing Membranes. Chem Rev 2021; 121:2020-2108. [PMID: 33464892 PMCID: PMC7908018 DOI: 10.1021/acs.chemrev.0c00712] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Indexed: 12/16/2022]
Abstract
This review focuses on key components of respiratory and photosynthetic energy-transduction systems: the cytochrome bc1 and b6f (Cytbc1/b6f) membranous multisubunit homodimeric complexes. These remarkable molecular machines catalyze electron transfer from membranous quinones to water-soluble electron carriers (such as cytochromes c or plastocyanin), coupling electron flow to proton translocation across the energy-transducing membrane and contributing to the generation of a transmembrane electrochemical potential gradient, which powers cellular metabolism in the majority of living organisms. Cytsbc1/b6f share many similarities but also have significant differences. While decades of research have provided extensive knowledge on these enzymes, several important aspects of their molecular mechanisms remain to be elucidated. We summarize a broad range of structural, mechanistic, and physiological aspects required for function of Cytbc1/b6f, combining textbook fundamentals with new intriguing concepts that have emerged from more recent studies. The discussion covers but is not limited to (i) mechanisms of energy-conserving bifurcation of electron pathway and energy-wasting superoxide generation at the quinol oxidation site, (ii) the mechanism by which semiquinone is stabilized at the quinone reduction site, (iii) interactions with substrates and specific inhibitors, (iv) intermonomer electron transfer and the role of a dimeric complex, and (v) higher levels of organization and regulation that involve Cytsbc1/b6f. In addressing these topics, we point out existing uncertainties and controversies, which, as suggested, will drive further research in this field.
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Affiliation(s)
- Marcin Sarewicz
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Sebastian Pintscher
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Rafał Pietras
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Arkadiusz Borek
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Łukasz Bujnowicz
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Guy Hanke
- School
of Biological and Chemical Sciences, Queen
Mary University of London, London E1 4NS, U.K.
| | - William A. Cramer
- Department
of Biological Sciences, Purdue University, West Lafayette, Indiana 47907 United States
| | - Giovanni Finazzi
- Laboratoire
de Physiologie Cellulaire et Végétale, Université Grenoble Alpes, Centre National Recherche Scientifique,
Commissariat Energie Atomique et Energies Alternatives, Institut National
Recherche l’agriculture, l’alimentation et l’environnement, 38054 Grenoble Cedex 9, France
| | - Artur Osyczka
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
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19
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Malone LA, Proctor MS, Hitchcock A, Hunter CN, Johnson MP. Cytochrome b 6f - Orchestrator of photosynthetic electron transfer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148380. [PMID: 33460588 DOI: 10.1016/j.bbabio.2021.148380] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 01/06/2021] [Accepted: 01/09/2021] [Indexed: 11/18/2022]
Abstract
Cytochrome b6f (cytb6f) lies at the heart of the light-dependent reactions of oxygenic photosynthesis, where it serves as a link between photosystem II (PSII) and photosystem I (PSI) through the oxidation and reduction of the electron carriers plastoquinol (PQH2) and plastocyanin (Pc). A mechanism of electron bifurcation, known as the Q-cycle, couples electron transfer to the generation of a transmembrane proton gradient for ATP synthesis. Cytb6f catalyses the rate-limiting step in linear electron transfer (LET), is pivotal for cyclic electron transfer (CET) and plays a key role as a redox-sensing hub involved in the regulation of light-harvesting, electron transfer and photosynthetic gene expression. Together, these characteristics make cytb6f a judicious target for genetic manipulation to enhance photosynthetic yield, a strategy which already shows promise. In this review we will outline the structure and function of cytb6f with a particular focus on new insights provided by the recent high-resolution map of the complex from Spinach.
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Affiliation(s)
- Lorna A Malone
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Matthew S Proctor
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Andrew Hitchcock
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.
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20
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Okegawa Y, Motohashi K. M-Type Thioredoxins Regulate the PGR5/PGRL1-Dependent Pathway by Forming a Disulfide-Linked Complex with PGRL1. THE PLANT CELL 2020; 32:3866-3883. [PMID: 33037145 PMCID: PMC7721319 DOI: 10.1105/tpc.20.00304] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 09/16/2020] [Accepted: 10/07/2020] [Indexed: 05/11/2023]
Abstract
In addition to linear electron transport, photosystem I cyclic electron transport (PSI-CET) contributes to photosynthesis and photoprotection. In Arabidopsis (Arabidopsis thaliana), PSI-CET consists of two partially redundant pathways, one of which is the PROTON GRADIENT REGULATION5 (PGR5)/PGR5-LIKE PHOTOSYNTHETIC PHENOTYPE1 (PGRL1)-dependent pathway. Although the physiological significance of PSI-CET is widely recognized, the regulatory mechanism behind these pathways remains largely unknown. Here, we report on the regulation of the PGR5/PGRL1-dependent pathway by the m-type thioredoxins (Trx m). Genetic and phenotypic characterizations of multiple mutants indicated the physiological interaction between Trx m and the PGR5/PGRL1-dependent pathway in vivo. Using purified Trx proteins and ruptured chloroplasts, in vitro, we showed that the reduced form of Trx m specifically decreased the PGR5/PGRL1-dependent plastoquinone reduction. In planta, Trx m4 directly interacted with PGRL1 via disulfide complex formation. Analysis of the transgenic plants expressing PGRL1 Cys variants demonstrated that Cys-123 of PGRL1 is required for Trx m4-PGRL1 complex formation. Furthermore, the Trx m4-PGRL1 complex was transiently dissociated during the induction of photosynthesis. We propose that Trx m directly regulates the PGR5/PGRL1-dependent pathway by complex formation with PGRL1.
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Affiliation(s)
- Yuki Okegawa
- Department of Frontier Life Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo Motoyama, Kita-Ku, Kyoto 603-8555, Japan
- Center for Plant Sciences, Kyoto Sangyo University, Kamigamo Motoyama, Kita-Ku, Kyoto 603-8555, Japan
| | - Ken Motohashi
- Department of Frontier Life Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo Motoyama, Kita-Ku, Kyoto 603-8555, Japan
- Center for Plant Sciences, Kyoto Sangyo University, Kamigamo Motoyama, Kita-Ku, Kyoto 603-8555, Japan
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21
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Stirbet A, Lazár D, Guo Y, Govindjee G. Photosynthesis: basics, history and modelling. ANNALS OF BOTANY 2020; 126:511-537. [PMID: 31641747 PMCID: PMC7489092 DOI: 10.1093/aob/mcz171] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/06/2019] [Accepted: 10/21/2019] [Indexed: 05/02/2023]
Abstract
BACKGROUND With limited agricultural land and increasing human population, it is essential to enhance overall photosynthesis and thus productivity. Oxygenic photosynthesis begins with light absorption, followed by excitation energy transfer to the reaction centres, primary photochemistry, electron and proton transport, NADPH and ATP synthesis, and then CO2 fixation (Calvin-Benson cycle, as well as Hatch-Slack cycle). Here we cover some of the discoveries related to this process, such as the existence of two light reactions and two photosystems connected by an electron transport 'chain' (the Z-scheme), chemiosmotic hypothesis for ATP synthesis, water oxidation clock for oxygen evolution, steps for carbon fixation, and finally the diverse mechanisms of regulatory processes, such as 'state transitions' and 'non-photochemical quenching' of the excited state of chlorophyll a. SCOPE In this review, we emphasize that mathematical modelling is a highly valuable tool in understanding and making predictions regarding photosynthesis. Different mathematical models have been used to examine current theories on diverse photosynthetic processes; these have been validated through simulation(s) of available experimental data, such as chlorophyll a fluorescence induction, measured with fluorometers using continuous (or modulated) exciting light, and absorbance changes at 820 nm (ΔA820) related to redox changes in P700, the reaction centre of photosystem I. CONCLUSIONS We highlight here the important role of modelling in deciphering and untangling complex photosynthesis processes taking place simultaneously, as well as in predicting possible ways to obtain higher biomass and productivity in plants, algae and cyanobacteria.
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Affiliation(s)
| | - Dušan Lazár
- Department of Biophysics, Center of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Ya Guo
- Key Laboratory of Advanced Process Control for Light Industry (Ministry of Education), Jiangnan University, Wuxi, China
- University of Missouri, Columbia, MO, USA
| | - Govindjee Govindjee
- Department of Biochemistry, Department of Plant Biology, and Center of Biophysics & Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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22
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Wei L, Fan B, Yi J, Xie T, Liu K, Ma W. Mechanistic insights into pH-dependent H 2 photoproduction in bisulfite-treated Chlamydomonas cells. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:64. [PMID: 32280372 PMCID: PMC7132995 DOI: 10.1186/s13068-020-01704-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/27/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Bisulfite addition is an important H2 photoproduction strategy that removes O2 and activates hydrogenase. The pH values of cell cultures can change the ratio of bisulfite to sulfite, which may affect H2 photoproduction. However, little is known regarding the pH effect of bisulfite addition on H2 photoproduction and relevant underlying mechanism. RESULTS Here, changes in H2 photoproduction with different initial extracellular pH values showed a parabolic distribution and a pH of 8.0 is an optimal value for H2 photoproduction in Chlamydomonas reinhardtii cells treated with bisulfite. Compared to the growth pH (pH 7.3), increased photoproduction of H2 at this optimal pH was primarily caused by a relatively high residual activity of photosystem II (PSII), which provides a relatively plentiful source of electrons for H2 photoproduction. Such increased H2 photoproduction was most likely a result of decreased the ratio of bisulfite to sulfite, consistent with the result that the toxicity of bisulfite on PSII was much more than that of sulfite. This possibility was corroborated by the result that treatment with a combination of 7 mM bisulfite and 6 mM sulfite further enhanced H2 photoproduction compared with 13 mM bisulfite alone. CONCLUSIONS Collectively, our findings provide novel mechanistic insights into pH-dependent H2 photoproduction in C. reinhardtii cells treated with bisulfite, and demonstrate that sulfite addition is another important strategy for H2 photoproduction, just like bisulfite addition.
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Affiliation(s)
- Lanzhen Wei
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Guilin Road 100, Shanghai, 200234 China
| | - Baoqiang Fan
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Guilin Road 100, Shanghai, 200234 China
| | - Jing Yi
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Guilin Road 100, Shanghai, 200234 China
| | - Tianqun Xie
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Guilin Road 100, Shanghai, 200234 China
| | - Kun Liu
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Guilin Road 100, Shanghai, 200234 China
| | - Weimin Ma
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Guilin Road 100, Shanghai, 200234 China
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Dann M, Leister D. Evidence that cyanobacterial Sll1217 functions analogously to PGRL1 in enhancing PGR5-dependent cyclic electron flow. Nat Commun 2019; 10:5299. [PMID: 31757966 PMCID: PMC6876563 DOI: 10.1038/s41467-019-13223-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 10/29/2019] [Indexed: 11/19/2022] Open
Abstract
In plants and cyanobacteria, the PGR5 protein contributes to cyclic electron flow around photosystem I. In plants, PGR5 interacts with PGRL1 during cyclic electron flow, but cyanobacteria appear to lack PGRL1 proteins. We have heterologously expressed the PGR5 and PGRL1 proteins from the plant Arabidopsis in various genetic backgrounds in the cyanobacterium Synechocystis. Our results show that plant PGR5 suffices to re-establish cyanobacterial cyclic electron flow (CEF), albeit less efficiently than the cyanobacterial PGR5 or the plant PGR5 and PGRL1 proteins together. A mutation that inactivates Arabidopsis PGR5 destabilises the protein in Synechocystis. Furthermore, the Synechocystis protein Sll1217, which exhibits weak sequence similarity with PGRL1, physically interacts with both plant and cyanobacterial PGR5 proteins, and stimulates CEF in Synechocystis. Therefore, Sll1217 partially acts as a PGRL1 analogue, the mode of action of PGR5 and PGRL1/Sll1217 proteins is similar in cyanobacteria and plants, and PGRL1 could have evolved from a cyanobacterial ancestor.
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Affiliation(s)
- Marcel Dann
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians University Munich, Großhaderner Str. 2, D-82152, Planegg-Martinsried, Germany
| | - Dario Leister
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians University Munich, Großhaderner Str. 2, D-82152, Planegg-Martinsried, Germany.
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24
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Zhang MM, Fan DY, Murakami K, Badger MR, Sun GY, Chow WS. Partially Dissecting Electron Fluxes in Both Photosystems in Spinach Leaf Disks during Photosynthetic Induction. PLANT & CELL PHYSIOLOGY 2019; 60:2206-2219. [PMID: 31271439 DOI: 10.1093/pcp/pcz114] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Accepted: 05/29/2019] [Indexed: 06/09/2023]
Abstract
Photosynthetic induction, a gradual increase in photosynthetic rate on a transition from darkness or low light to high light, has ecological significance, impact on biomass accumulation in fluctuating light and relevance to photoprotection in strong light. However, the experimental quantification of the component electron fluxes in and around both photosystems during induction has been rare. Combining optimized chlorophyll fluorescence, the redox kinetics of P700 [primary electron donor in Photosystem I (PSI)] and membrane inlet mass spectrometry in the absence/presence of inhibitors/mediator, we partially estimated the components of electron fluxes in spinach leaf disks on transition from darkness to 1,000 �mol photons�m-2�s-1 for up to 10 min, obtaining the following findings: (i) the partitioning of energy between both photosystems did not change noticeably; (ii) in Photosystem II (PSII), the combined cyclic electron flow (CEF2) and charge recombination (CR2) to the ground state decreased gradually toward 0 in steady state; (iii) oxygen reduction by electrons from PSII, partly bypassing PSI, was small but measurable; (iv) cyclic electron flow around PSI (CEF1) peaked before becoming somewhat steady; (v) peak magnitudes of some of the electron fluxes, all probably photoprotective, were in the descending order: CEF1 > CEF2 + CR2 > chloroplast O2 uptake; and (vi) the chloroplast NADH dehydrogenase-like complex appeared to aid the antimycin A-sensitive CEF1. The results are important for fine-tuning in silico simulation of in vivo photosynthetic electron transport processes; such simulation is, in turn, necessary to probe partial processes in a complex network of interactions in response to environmental changes.
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Affiliation(s)
- Meng-Meng Zhang
- Department of Plant Physiology, College of Life Science, Northeast Forestry University, Harbin, Heilongjiang, China
- Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - Da-Yong Fan
- Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, Australia
- College of Forestry, Beijing Forestry University, Beijing, China
| | - Keach Murakami
- Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, Australia
- National Agriculture and Food Research Organization (NARO), Hokkaido Agricultural Research Center (HARC), Hitsujigaoka 1, Toyohira, Sapporo, Japan
| | - Murray R Badger
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - Guang-Yu Sun
- Department of Plant Physiology, College of Life Science, Northeast Forestry University, Harbin, Heilongjiang, China
| | - Wah Soon Chow
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Acton, ACT, Australia
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25
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Johnson MP, Wientjes E. The relevance of dynamic thylakoid organisation to photosynthetic regulation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1861:148039. [PMID: 31228404 DOI: 10.1016/j.bbabio.2019.06.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 06/14/2019] [Accepted: 06/15/2019] [Indexed: 12/11/2022]
Abstract
The higher plant chloroplast thylakoid membrane system performs the light-dependent reactions of photosynthesis. These provide the ATP and NADPH required for the fixation of CO2 into biomass by the Calvin-Benson cycle and a range of other metabolic reactions in the stroma. Land plants are frequently challenged by fluctuations in their environment, such as light, nutrient and water availability, which can create a mismatch between the amounts of ATP and NADPH produced and the amounts required by the downstream metabolism. Left unchecked, such imbalances can lead to the production of reactive oxygen species that damage the plant and harm productivity. Fortunately, plants have evolved a complex range of regulatory processes to avoid or minimize such deleterious effects by controlling the efficiency of light harvesting and electron transfer in the thylakoid membrane. Generally the regulation of the light reactions has been studied and conceptualised at the microscopic level of protein-protein and protein-ligand interactions, however in recent years dynamic changes in the thylakoid macrostructure itself have been recognised to play a significant role in regulating light harvesting and electron transfer. Here we review the evidence for the involvement of macrostructural changes in photosynthetic regulation and review the techniques that brought this evidence to light.
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Affiliation(s)
- Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom.
| | - Emilie Wientjes
- Laboratory of Biophysics, Wageningen University, Stippeneng 4, 6708 WE Wageningen, the Netherlands
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26
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Nawrocki W, Bailleul B, Cardol P, Rappaport F, Wollman FA, Joliot P. Maximal cyclic electron flow rate is independent of PGRL1 in Chlamydomonas. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:425-432. [DOI: 10.1016/j.bbabio.2019.01.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 12/08/2018] [Accepted: 01/25/2019] [Indexed: 11/30/2022]
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27
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Nakano H, Yamamoto H, Shikanai T. Contribution of NDH-dependent cyclic electron transport around photosystem I to the generation of proton motive force in the weak mutant allele of pgr5. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:369-374. [PMID: 30878346 DOI: 10.1016/j.bbabio.2019.03.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 01/29/2019] [Accepted: 03/11/2019] [Indexed: 01/05/2023]
Abstract
In angiosperms, cyclic electron transport (CET) around photosystem I (PSI) consists of two pathways, depending on PGR5/PGRL1 proteins and the chloroplast NDH complex. In single mutants defective in chloroplast NDH, photosynthetic electron transport is only slightly affected at low light intensity, but in double mutants impaired in both CET pathways photosynthesis and plant growth are severely affected. The question is whether this strong mutant phenotype observed in double mutants can be simply explained by the additive effect of defects in both CET pathways. In this study, we used the weak mutant allele of pgr5-2 for the background of double mutants to avoid possible problems caused by the secondary effects due to the strong mutant phenotype. In two double mutants, crr2-2 pgr5-2 and ndhs-1 pgr5-2, the plant growth was unaffected and linear electron transport was only slightly affected. However, NPQ induction was more severely impaired in the double mutants than in the pgr5-2 single mutant. A similar trend was observed in the size of the proton motive force. Despite the slight reduction in photosystem II parameters, PSI parameters were severely affected in the pgr5-2 single mutant, the phenotype that was further enhanced by adding the NDH defects. Despite the lack of ∆pH-dependent regulation at the cytochrome b6f complex (donor-side regulation of PSI), the plastoquinone pool was more reduced in the double mutants than in the pgr5-2 single mutants. This phenotype suggests that both PGR5/PGRL1- and NDH-dependent CET contribute to supply sufficient acceptors from PSI by balancing the ATP/NADPH production ratio.
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Affiliation(s)
- Hiroshi Nakano
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
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28
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Nawrocki WJ, Bailleul B, Picot D, Cardol P, Rappaport F, Wollman FA, Joliot P. The mechanism of cyclic electron flow. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:433-438. [PMID: 30827891 DOI: 10.1016/j.bbabio.2018.12.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 12/08/2018] [Accepted: 12/08/2018] [Indexed: 12/16/2022]
Abstract
Apart from the canonical light-driven linear electron flow (LEF) from water to CO2, numerous regulatory and alternative electron transfer pathways exist in chloroplasts. One of them is the cyclic electron flow around Photosystem I (CEF), contributing to photoprotection of both Photosystem I and II (PSI, PSII) and supplying extra ATP to fix atmospheric carbon. Nonetheless, CEF remains an enigma in the field of functional photosynthesis as we lack understanding of its pathway. Here, we address the discrepancies between functional and genetic/biochemical data in the literature and formulate novel hypotheses about the pathway and regulation of CEF based on recent structural and kinetic information.
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Affiliation(s)
- W J Nawrocki
- Institut de Biologie Physico-Chimique, UMR 7141 CNRS-UPMC, 13 rue P. et M. Curie, 75005 Paris, France; Laboratoire de Génétique et Physiologie des Microalgues, Institut de Botanique, Université de Liège, 4, Chemin de la Vallée, B-4000 Liège, Belgium.
| | - B Bailleul
- Institut de Biologie Physico-Chimique, UMR 7141 CNRS-UPMC, 13 rue P. et M. Curie, 75005 Paris, France
| | - D Picot
- Institut de Biologie Physico-Chimique, UMR 7099 CNRS-UPMC, 13 rue P. et M. Curie, 75005 Paris, France
| | - P Cardol
- Laboratoire de Génétique et Physiologie des Microalgues, Institut de Botanique, Université de Liège, 4, Chemin de la Vallée, B-4000 Liège, Belgium
| | - F Rappaport
- Institut de Biologie Physico-Chimique, UMR 7141 CNRS-UPMC, 13 rue P. et M. Curie, 75005 Paris, France
| | - F-A Wollman
- Institut de Biologie Physico-Chimique, UMR 7141 CNRS-UPMC, 13 rue P. et M. Curie, 75005 Paris, France
| | - P Joliot
- Institut de Biologie Physico-Chimique, UMR 7141 CNRS-UPMC, 13 rue P. et M. Curie, 75005 Paris, France
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29
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Takagi D, Ifuku K, Nishimura T, Miyake C. Antimycin A inhibits cytochrome b 559-mediated cyclic electron flow within photosystem II. PHOTOSYNTHESIS RESEARCH 2019; 139:487-498. [PMID: 29790043 DOI: 10.1007/s11120-018-0519-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 05/15/2018] [Indexed: 05/27/2023]
Abstract
The light reactions of photosynthesis are known to comprise both linear and cyclic electron flow in order to convert light energy into chemical energy in the form of NADPH and ATP. Antimycin A (AA) has been proposed as an inhibitor of ferredoxin-dependent cyclic electron flow around photosystem I (CEF-PSI) in photosynthesis research. However, its precise inhibitory mechanism and target site had not been elucidated yet. Here we show that AA inhibits the cyclic (alternative) electron flow via cytochrome b559 (Cyt b559) within photosystem II (CEF-PSII). When AA was applied to thylakoid membranes isolated from spinach leaves, the high potential form of Cyt b559, which was reduced in the dark, was transformed into the lower potential forms and readily oxidized by molecular oxygen. In the absence of AA, the reduced Cyt b559 was oxidized by P680+ upon light illumination and re-reduced in the dark, mainly by the electron from the QB site on the acceptor side of PSII. In contrast, AA suppressed the oxidation of Cyt b559 and induced its reduction under the illumination. This inhibition of Cyt b559 oxidation by AA enhanced photoinhibition of PSII. Based on the above results, we propose caution regarding the use of AA for evaluating CEF-PSI per se and concurrently propose that AA provides for new insights into, and interpretations of, the physiological importance of Cyt b559, rather than that of CEF-PSI in photosynthetic organisms.
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Affiliation(s)
- Daisuke Takagi
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada, 657-8511, Japan.
| | - Kentaro Ifuku
- Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Taishi Nishimura
- Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Chikahiro Miyake
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada, 657-8511, Japan
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30
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Wei L, Li X, Fan B, Ran Z, Ma W. A Stepwise NaHSO 3 Addition Mode Greatly Improves H 2 Photoproduction in Chlamydomonas reinhardtii. FRONTIERS IN PLANT SCIENCE 2018; 9:1532. [PMID: 30429859 PMCID: PMC6220153 DOI: 10.3389/fpls.2018.01532] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 09/28/2018] [Indexed: 05/23/2023]
Abstract
NaHSO3 addition greatly increases the yield of H2 photoproduction in a unicellular green alga Chlamydomonas reinhardtii through removing O2 and activating hydrogenase but significantly impairs the activity of PSII, an electron source for H2 photoproduction. Here, a stepwise addition mode of total 13 mM NaHSO3, an optimal concentration for H2 photoproduction of C. reinhardtii identified in a previous one step addition method, significantly improved H2 photoproduction. Such improvement was believed to be the result of increased residual PSII activity in an anaerobic background, but was at least independent of two alternative electron sinks for H2 photoproduction, cyclic electron transport around PSI and CO2 assimilation. Based on the above results, we propose that increased residual PSII activity in an anaerobic environment is an efficient strategy to enhance H2 photoproduction in C. reinhardtii, and the stepwise NaHSO3 addition mode is a case study in the strategy.
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Wang C, Takahashi H, Shikanai T. PROTON GRADIENT REGULATION 5 contributes to ferredoxin-dependent cyclic phosphorylation in ruptured chloroplasts. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:1173-1179. [DOI: 10.1016/j.bbabio.2018.07.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 07/26/2018] [Accepted: 07/30/2018] [Indexed: 10/28/2022]
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32
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Yu B, Niu J, Feng J, Xu M, Xie X, Gu W, Gao S, Wang G. Regulation of Ferredoxin-NADP + Oxidoreductase to Cyclic Electron Transport in High Salinity Stressed Pyropia yezoensis. FRONTIERS IN PLANT SCIENCE 2018; 9:1092. [PMID: 30090109 PMCID: PMC6068275 DOI: 10.3389/fpls.2018.01092] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/05/2018] [Indexed: 05/19/2023]
Abstract
Pyropia yezoensis can survive the severe water loss that occurs during low tide, making it an ideal species to investigate the acclimation mechanism of intertidal seaweed to special extreme environments. In this study, we determined the effects of high salinity on photosynthesis using increasing salinity around algal tissues. Both electron transport rates, ETR (I) and ETR (II), showed continuous decreases as the salinity increased. However, the difference between these factors remained relatively stable, similar to the control. Inhibitor experiments illustrated that there were at least three different cyclic electron transport pathways. Under conditions of severe salinity, NAD(P)H could be exploited as an endogenous electron donor to reduce the plastoquinone pool in Py. yezoensis. Based on these findings, we next examined how these different cyclic electron transport (CETs) pathways were coordinated by cloning the gene (HM370553) for ferredoxin-NADP+ oxidoreductase (FNR). A phylogenetic tree was constructed, and the evolutionary relationships among different FNRs were evaluated. The results indicated that the Py. yezoensis FNR showed a closer relationship with cyanobacterial FNR. The results of both real-time polymerase chain reaction and western blotting showed that the enzyme was upregulated under 90-120‰ salinity. Due to the structure-function correlations in organism, Py. yezoensis FNR was proposed to be involved in NAD(P)H-dependent Fd+ reduction under severe salinity conditions. Thus, through the connection between different donors bridged by FNR, electrons were channeled toward distinct routes according to the different metabolic demands. This was expected to make the electron transfer in the chloroplasts become more flexible and to contribute greatly to acclimation of Py. yezoensis to the extreme variable environments in the intertidal zone.
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Affiliation(s)
- Bin Yu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Jianfeng Niu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Jianhua Feng
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Meiling Xu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Xiujun Xie
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Wenhui Gu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Shan Gao
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Guangce Wang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
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Otani T, Kato Y, Shikanai T. Specific substitutions of light-harvesting complex I proteins associated with photosystem I are required for supercomplex formation with chloroplast NADH dehydrogenase-like complex. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 94:122-130. [PMID: 29385648 DOI: 10.1111/tpj.13846] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 01/15/2018] [Indexed: 05/25/2023]
Abstract
In Arabidopsis, the chloroplast NADH-dehydrogenase-like (NDH) complex is sandwiched between two copies of photosystem I (PSI) supercomplex, consisting of a PSI core and four light-harvesting complex I (LHCI) proteins (PSI-LHCI) to form the NDH-PSI supercomplex. Two minor LHCI proteins, Lhca5 and Lhca6, contribute to the interaction of each PSI-LHCI copy with the NDH complex. Here, large-pore blue-native gel electrophoresis revealed that, in addition to this complex, there were at least two types of higher-order association of more LHCI copies with the NDH complex. In single-particle images, this higher-order association of PSI-LHCI preferentially occurs at the left side of the NDH complex when viewed from the stromal side, placing subcomplex A at the top (Yadav et al., Biochim. Biophys. Acta - Bioenerg., 1858, 2017, 12). The association was impaired in the lhca6 mutant but not in the lhca5 mutant, suggesting that the left copy of PSI-LHCI was linked to the NDH complex via Lhca6. From an analysis of subunit compositions of the NDH-PSI supercomplex in lhca5 and lhca6 mutants, we propose that Lhca6 substitutes for Lhca2 in the left copy of PSI-LHCI, whereas Lhca5 substitutes for Lhca4 in the right copy. In the lhca2 mutant, Lhca3 was specifically stabilized in the NDH-PSI supercomplex through heterodimer formation with Lhca6. In the left copy of PSI-LHCI, subcomplex B, Lhca6 and NdhD likely formed the core of the supercomplex interaction. In contrast, a larger protein complex, including at least subcomplexes B and L and NdhB, was needed to form the contact site with Lhca5 in the right copy of PSI-LHCI.
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Affiliation(s)
- Takuto Otani
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Yoshinobu Kato
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
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Murata N, Nishiyama Y. ATP is a driving force in the repair of photosystem II during photoinhibition. PLANT, CELL & ENVIRONMENT 2018; 41:285-299. [PMID: 29210214 DOI: 10.1111/pce.13108] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 11/21/2017] [Accepted: 11/22/2017] [Indexed: 05/15/2023]
Abstract
Repair of photosystem II (PSII) during photoinhibition involves replacement of photodamaged D1 protein by newly synthesized D1 protein. In this review, we summarize evidence for the indispensability of ATP in the degradation and synthesis of D1 during the repair of PSII. Synthesis of one molecule of the D1 protein consumes more than 1,300 molecules of ATP equivalents. The degradation of photodamaged D1 by FtsH protease also consumes approximately 240 molecules of ATP. In addition, ATP is required for several other aspects of the repair of PSII, such as transcription of psbA genes. These requirements for ATP during the repair of PSII have been demonstrated by experiments showing that the synthesis of D1 and the repair of PSII are interrupted by inhibitors of ATP synthase and uncouplers of ATP synthesis, as well as by mutation of components of ATP synthase. We discuss the contribution of cyclic electron transport around photosystem I to the repair of PSII. Furthermore, we introduce new terms relevant to the regulation of the PSII repair, namely, "ATP-dependent regulation" and "redox-dependent regulation," and we discuss the possible contribution of the ATP-dependent regulation of PSII repair under environmental stress.
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Affiliation(s)
- Norio Murata
- National Institute for Basic Biology, Okazaki, 444-8585, Japan
| | - Yoshitaka Nishiyama
- Department of Biochemistry and Molecular Biology and Institute for Environmental Science and Technology, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570, Japan
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35
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Cherepanov DA, Milanovsky GE, Petrova AA, Tikhonov AN, Semenov AY. Electron Transfer through the Acceptor Side of Photosystem I: Interaction with Exogenous Acceptors and Molecular Oxygen. BIOCHEMISTRY (MOSCOW) 2018; 82:1249-1268. [PMID: 29223152 DOI: 10.1134/s0006297917110037] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This review considers the state-of-the-art on mechanisms and alternative pathways of electron transfer in photosynthetic electron transport chains of chloroplasts and cyanobacteria. The mechanisms of electron transport control between photosystems (PS) I and II and the Calvin-Benson cycle are considered. The redistribution of electron fluxes between the noncyclic, cyclic, and pseudocyclic pathways plays an important role in the regulation of photosynthesis. Mathematical modeling of light-induced electron transport processes is considered. Particular attention is given to the electron transfer reactions on the acceptor side of PS I and to interactions of PS I with exogenous acceptors, including molecular oxygen. A kinetic model of PS I and its interaction with exogenous electron acceptors has been developed. This model is based on experimental kinetics of charge recombination in isolated PS I. Kinetic and thermodynamic parameters of the electron transfer reactions in PS I are scrutinized. The free energies of electron transfer between quinone acceptors A1A/A1B in the symmetric redox cofactor branches of PS I and iron-sulfur clusters FX, FA, and FB have been estimated. The second-order rate constants of electron transfer from PS I to external acceptors have been determined. The data suggest that byproduct formation of superoxide radical in PS I due to the reduction of molecular oxygen in the A1 site (Mehler reaction) can exceed 0.3% of the total electron flux in PS I.
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Affiliation(s)
- D A Cherepanov
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, 119992, Russia.
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36
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Lakatos G, Balogh D, Farkas A, Ördög V, Nagy PT, Bíró T, Maróti G. Factors influencing algal photobiohydrogen production in algal-bacterial co-cultures. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.10.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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37
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38
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Alric J, Johnson X. Alternative electron transport pathways in photosynthesis: a confluence of regulation. CURRENT OPINION IN PLANT BIOLOGY 2017; 37:78-86. [PMID: 28426976 DOI: 10.1016/j.pbi.2017.03.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 03/23/2017] [Accepted: 03/28/2017] [Indexed: 05/19/2023]
Abstract
Photosynthetic reactions proceed along a linear electron transfer chain linking water oxidation at photosystem II (PSII) to CO2 reduction in the Calvin-Benson-Bassham cycle. Alternative pathways poise the electron carriers along the chain in response to changing light, temperature and CO2 inputs, under prolonged hydration stress and during development. We describe recent literature that reports the physiological functions of new molecular players. Such highlights include the flavodiiron proteins and their important role in the green lineage. The parsing of the proton-motive force between ΔpH and Δψ, regulated in many different ways (cyclic electron flow, ATPsynthase conductivity, ion/H+ transporters), is comprehensively reported. This review focuses on an integrated description of alternative electron transfer pathways and how they contribute to photosynthetic productivity in the context of plant fitness to the environment.
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Affiliation(s)
- Jean Alric
- CEA, CNRS, Aix-Marseille Université, Institut de Biosciences et Biotechnologies Aix-Marseille, UMR 7265, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, Saint-Paul-lez-Durance F-13108, France
| | - Xenie Johnson
- CEA, CNRS, Aix-Marseille Université, Institut de Biosciences et Biotechnologies Aix-Marseille, UMR 7265, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, Saint-Paul-lez-Durance F-13108, France.
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Otani T, Yamamoto H, Shikanai T. Stromal Loop of Lhca6 is Responsible for the Linker Function Required for the NDH-PSI Supercomplex Formation. PLANT & CELL PHYSIOLOGY 2017; 58:851-861. [PMID: 28184910 DOI: 10.1093/pcp/pcx009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 01/15/2017] [Indexed: 05/25/2023]
Abstract
The light-harvesting complex I (LHCI) proteins in Arabidopsis thaliana are encoded by six genes. Major LHCI proteins (Lhca1-Lhca4) harvest light energy and transfer the resulting excitation energy to the PSI core by forming a PSI supercomplex. In contrast, the minor LHCI proteins Lhca5 and Lhca6 contribute to supercomplex formation between the PSI supercomplex and the chloroplast NADH dehydrogenase-like (NDH) complex, although Lhca5 is also solely associated with the PSI supercomplex. Lhca6 was branched from Lhca2 during the evolution of land plants. In this study, we focused on the molecular evolution involved in the transition from a major LHCI, Lhca2, to the linker protein Lhca6. To elucidate the domains of Lhca6 responsible for linker function, we systematically swapped domains between the two LHCI proteins. To overcome problems due to the low stability of chimeric proteins, we employed sensitive methods to evaluate supercomplex formation: we monitored NDH activity by using Chl fluorescence analysis and detected NDH-PSI supercomplex formation by using protein blot analysis in the form of two-dimensional blue-native (BN)/SDS-PAGE. The stromal loop of Lhca6 was shown to be necessary and sufficient for linker function. Chimeric Lhca6, in which the stromal loop was substituted by that of Lhca2, was not functional as a linker and was detected at the position of the PSI supercomplex in the BN-polyacrylamide gel. The stromal loop of Lhca6 is likely to be necessary for the interaction with chloroplast NDH, rather than for the association with the PSI supercomplex.
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Affiliation(s)
- Takuto Otani
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, Japan
- CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo, Japan
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, Japan
- CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo, Japan
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Shikanai T, Yamamoto H. Contribution of Cyclic and Pseudo-cyclic Electron Transport to the Formation of Proton Motive Force in Chloroplasts. MOLECULAR PLANT 2017; 10:20-29. [PMID: 27575692 DOI: 10.1016/j.molp.2016.08.004] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 07/28/2016] [Accepted: 08/08/2016] [Indexed: 05/05/2023]
Abstract
Photosynthetic electron transport is coupled to proton translocation across the thylakoid membrane, resulting in the formation of a trans-thylakoid proton gradient (ΔpH) and membrane potential (Δψ). Ion transporters and channels localized to the thylakoid membrane regulate the contribution of each component to the proton motive force (pmf). Although both ΔpH and Δψ contribute to ATP synthesis as pmf, only ΔpH downregulates photosynthetic electron transport via the acidification of the thylakoid lumen by inducing thermal dissipation of excessive absorbed light energy from photosystem II antennae and slowing down of the electron transport through the cytochrome b6f complex. To optimize the tradeoff between efficient light energy utilization and protection of both photosystems against photodamage, plants have to regulate the pmf amplitude and its components, ΔpH and Δψ. Cyclic electron transport around photosystem I (PSI) is a major regulator of the pmf amplitude by generating pmf independently of the net production of NADPH by linear electron transport. Chloroplast ATP synthase relaxes pmf for ATP synthesis, and its activity should be finely tuned for maintaining the size of the pmf during steady-state photosynthesis. Pseudo-cyclic electron transport mediated by flavodiiron protein (Flv) forms a large electron sink, which is essential for PSI photoprotection in fluctuating light in cyanobacteria. Flv is conserved from cyanobacteria to gymnosperms but not in angiosperms. The Arabidopsis proton gradient regulation 5 (pgr5) mutant is defective in the main pathway of PSI cyclic electron transport. By introducing Physcomitrella patens genes encoding Flvs, the function of PSI cyclic electron transport was substituted by that of Flv-dependent pseudo-cyclic electron transport. In transgenic plants, the size of the pmf was complemented to the wild-type level but the contribution of ΔpH to the total pmf was lower than that in the wild type. In the pgr5 mutant, the size of the pmf was drastically lowered by the absence of PSI cyclic electron transport. In the mutant, ΔpH occupied the majority of pmf, suggesting the presence of a mechanism for the homeostasis of luminal pH in the light. To avoid damage to photosynthetic electron transport by periods of excess solar energy, plants employ an intricate regulatory network involving alternative electron transport pathways, ion transporters/channels, and pH-dependent mechanisms for downregulating photosynthetic electron transport.
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Affiliation(s)
- Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 Japan; CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076 Japan.
| | - Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 Japan; CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076 Japan
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Labs M, Rühle T, Leister D. The antimycin A-sensitive pathway of cyclic electron flow: from 1963 to 2015. PHOTOSYNTHESIS RESEARCH 2016; 129:231-8. [PMID: 26781235 DOI: 10.1007/s11120-016-0217-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/08/2016] [Indexed: 05/09/2023]
Abstract
Cyclic electron flow has puzzled and divided the field of photosynthesis researchers for decades. This mainly concerns the proportion of its overall contribution to photosynthesis, as well as its components and molecular mechanism. Yet, it is irrefutable that the absence of cyclic electron flow has severe effects on plant growth. One of the two pathways mediating cyclic electron flow can be inhibited by antimycin A, a chemical that has also widely been used to characterize the mitochondrial respiratory chain. For the characterization of cyclic electron flow, antimycin A has been used since 1963, when ferredoxin was found to be the electron donor of the pathway. In 2013, antimycin A was used to identify the PGRL1/PGR5 complex as the ferredoxin:plastoquinone reductase completing the last puzzle piece of this pathway. The controversy has not ended, and here, we review the history of research on this process using the perspective of antimycin A as a crucial chemical for its characterization.
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Affiliation(s)
- Mathias Labs
- Plant Molecular Biology, Department Biology, Ludwig-Maximilians-University Munich (LMU), Planegg-Martinsried, 82152, Munich, Germany
| | - Thilo Rühle
- Plant Molecular Biology, Department Biology, Ludwig-Maximilians-University Munich (LMU), Planegg-Martinsried, 82152, Munich, Germany
| | - Dario Leister
- Plant Molecular Biology, Department Biology, Ludwig-Maximilians-University Munich (LMU), Planegg-Martinsried, 82152, Munich, Germany.
- Copenhagen Plant Science Centre (CPSC), Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark.
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Dumas L, Chazaux M, Peltier G, Johnson X, Alric J. Cytochrome b 6 f function and localization, phosphorylation state of thylakoid membrane proteins and consequences on cyclic electron flow. PHOTOSYNTHESIS RESEARCH 2016; 129:307-320. [PMID: 27534565 DOI: 10.1007/s11120-016-0298-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 07/27/2016] [Indexed: 06/06/2023]
Abstract
Both the structure and the protein composition of thylakoid membranes have an impact on light harvesting and electron transfer in the photosynthetic chain. Thylakoid membranes form stacks and lamellae where photosystem II and photosystem I localize, respectively. Light-harvesting complexes II can be associated to either PSII or PSI depending on the redox state of the plastoquinone pool, and their distribution is governed by state transitions. Upon state transitions, the thylakoid ultrastructure and lateral distribution of proteins along the membrane are subject to significant rearrangements. In addition, quinone diffusion is limited to membrane microdomains and the cytochrome b 6 f complex localizes either to PSII-containing grana stacks or PSI-containing stroma lamellae. Here, we discuss possible similarities or differences between green algae and C3 plants on the functional consequences of such heterogeneities in the photosynthetic electron transport chain and propose a model in which quinones, accepting electrons either from PSII (linear flow) or NDH/PGR pathways (cyclic flow), represent a crucial control point. Our aim is to give an integrated description of these processes and discuss their potential roles in the balance between linear and cyclic electron flows.
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Affiliation(s)
- Louis Dumas
- Laboratory of Microalgal and Bacterial Bioenergetics and Biotechnology, CEA Cadarache, CNRS, Aix-Marseille Université, UMR7161 BIAM - LB3M, 13108, Saint-Paul-lez-Durance, France
| | - Marie Chazaux
- Laboratory of Microalgal and Bacterial Bioenergetics and Biotechnology, CEA Cadarache, CNRS, Aix-Marseille Université, UMR7161 BIAM - LB3M, 13108, Saint-Paul-lez-Durance, France
| | - Gilles Peltier
- Laboratory of Microalgal and Bacterial Bioenergetics and Biotechnology, CEA Cadarache, CNRS, Aix-Marseille Université, UMR7161 BIAM - LB3M, 13108, Saint-Paul-lez-Durance, France
| | - Xenie Johnson
- Laboratory of Microalgal and Bacterial Bioenergetics and Biotechnology, CEA Cadarache, CNRS, Aix-Marseille Université, UMR7161 BIAM - LB3M, 13108, Saint-Paul-lez-Durance, France
| | - Jean Alric
- Laboratory of Microalgal and Bacterial Bioenergetics and Biotechnology, CEA Cadarache, CNRS, Aix-Marseille Université, UMR7161 BIAM - LB3M, 13108, Saint-Paul-lez-Durance, France.
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Shikanai T. Regulatory network of proton motive force: contribution of cyclic electron transport around photosystem I. PHOTOSYNTHESIS RESEARCH 2016; 129:253-60. [PMID: 26858094 DOI: 10.1007/s11120-016-0227-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 01/27/2016] [Indexed: 05/07/2023]
Abstract
Cyclic electron transport around photosystem I (PSI) generates ∆pH across the thylakoid membrane without net production of NADPH. In angiosperms, two pathways of PSI cyclic electron transport operate. The main pathway depends on PGR5/PGRL1 proteins and is likely identical to the historical Arnon's pathway. The minor pathway depends on chloroplast NADH dehydrogenase-like (NDH) complex. In assays of their rates in vivo, the two independent pathways are often mixed together. Theoretically, linear electron transport from water to NADP(+) cannot satisfy the ATP/NADPH production ratio required by the Calvin-Benson cycle and photorespiration. PGR5/PGRL1-dependent PSI cyclic electron transport contributes substantially to the supply of ATP for CO2 fixation, as does linear electron transport. Also, the contribution of chloroplast NDH cannot be ignored, especially at low light intensity, although the extent of the contribution depends on the plant species. An increase in proton conductivity of ATP synthase may compensate ATP synthesis to some extent in the pgr5 mutant. Combined with the decreased rate of ∆pH generation, however, this mechanism sacrifices homeostasis of the thylakoid lumen pH, seriously disturbing the pH-dependent regulation of photosynthetic electron transport, induction of qE, and downregulation of the cytochrome b 6 f complex. PGR5/PGRL1-dependent PSI cyclic electron transport produces sufficient proton motive force for ATP synthesis and the regulation of photosynthetic electron transport.
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Affiliation(s)
- Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan.
- CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo, 102-0076, Japan.
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Huang W, Yang YJ, Hu H, Cao KF, Zhang SB. Sustained Diurnal Stimulation of Cyclic Electron Flow in Two Tropical Tree Species Erythrophleum guineense and Khaya ivorensis. FRONTIERS IN PLANT SCIENCE 2016; 7:1068. [PMID: 27486473 PMCID: PMC4950474 DOI: 10.3389/fpls.2016.01068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 07/06/2016] [Indexed: 05/04/2023]
Abstract
The photosystem II (PSII) activity of C3 plants is usually inhibited at noon associated with high light but can be repaired fast in the afternoon. However, the diurnal variation of photosystem I (PSI) activity is unknown. Although, cyclic electron flow (CEF) has been documented as an important mechanism for photosynthesis, the diurnal variation of CEF in sun leaves is little known. We determined the diurnal changes in PSI and PSII activities, light energy dissipation in PSII and the P700 redox state in two tropical tree species Erythrophleum guineense and Khaya ivorensis grown in an open field. The PSI activity (as indicated by the maximum quantity of photo-oxidizable P700) was maintained stable during the daytime. CEF was strongly activated under high light at noon, accompanying with high levels of non-photochemical quenching (NPQ) and PSI oxidation ratio. In the afternoon, CEF was maintained at a relatively high level under low light, which was accompanied with low levels of NPQ and P700 oxidation ratio. These results indicated that CEF was flexibly modulated during daytime under fluctuating light conditions. Under high light at noon, CEF-dependent generation of proton gradient across the thylakoid membranes (ΔpH) mainly contributed to photoprotection for PSI and PSII. By comparison, at low light in the afternoon, the CEF-dependent formation of ΔpH may be important for PSII repair via an additional ATP synthesis.
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Affiliation(s)
- Wei Huang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany – Chinese Academy of Sciences, KunmingChina
- Yunnan Key Laboratory for Wild Plant ResourcesKunming, China
| | - Ying-Jie Yang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany – Chinese Academy of Sciences, KunmingChina
- Yunnan Key Laboratory for Wild Plant ResourcesKunming, China
| | - Hong Hu
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany – Chinese Academy of Sciences, KunmingChina
- Yunnan Key Laboratory for Wild Plant ResourcesKunming, China
| | - Kun-Fang Cao
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden – Chinese Academy of SciencesMengla, China
| | - Shi-Bao Zhang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany – Chinese Academy of Sciences, KunmingChina
- Yunnan Key Laboratory for Wild Plant ResourcesKunming, China
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45
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Shikanai T. Chloroplast NDH: A different enzyme with a structure similar to that of respiratory NADH dehydrogenase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1015-22. [DOI: 10.1016/j.bbabio.2015.10.013] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 10/21/2015] [Accepted: 10/26/2015] [Indexed: 11/28/2022]
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Nakajima Munekage Y. Light harvesting and chloroplast electron transport in NADP-malic enzyme type C4 plants. CURRENT OPINION IN PLANT BIOLOGY 2016; 31:9-15. [PMID: 26999307 DOI: 10.1016/j.pbi.2016.03.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 02/17/2016] [Accepted: 03/01/2016] [Indexed: 06/05/2023]
Abstract
The structure of thylakoids in chloroplasts and the organization of the electron transport chain changed dynamically during the evolution of C4 photosynthesis, especially in the nicotinamide adenine dinucleotide phosphate (NADP)-malic enzyme type C4 species. Stacked grana membranes are strongly reduced in the bundle sheath chloroplasts of these plants, where photosystem II activity is diminished and cyclic electron transport around photosystem I mainly occurs. This change optimizes the ATP/NADPH production ratio in bundle sheath chloroplasts to drive the metabolic cycle of C4 photosynthesis. This review summarizes the current model of light harvesting and electron transport in the NADP-malic enzyme type C4 plants and discusses how it changed during the evolution of C4 photosynthesis.
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Affiliation(s)
- Yuri Nakajima Munekage
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan.
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Munekage YN, Taniguchi YY. Promotion of Cyclic Electron Transport Around Photosystem I with the Development of C4 Photosynthesis. PLANT & CELL PHYSIOLOGY 2016; 57:897-903. [PMID: 26893472 DOI: 10.1093/pcp/pcw012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 01/11/2016] [Indexed: 06/05/2023]
Abstract
C4 photosynthesis is present in approximately 7,500 species classified into 19 families, including monocots and eudicots. In the majority of documented cases, a two-celled CO2-concentrating system that uses a metabolic cycle of four-carbon compounds is employed. C4 photosynthesis repeatedly evolved from C3 photosynthesis, possibly driven by the survival advantages it bestows in the hot, often dry, and nutrient-poor soils of the tropics and subtropics. The development of the C4 metabolic cycle greatly increased the ATP demand in chloroplasts during the evolution of malic enzyme-type C4 photosynthesis, and the additional ATP required for C4 metabolism may be produced by the cyclic electron transport around PSI. Recent studies have revealed the nature of cyclic electron transport and the elevation of its components during C4 evolution. In this review, we discuss the energy requirements of C3 and C4 photosynthesis, the current model of cyclic electron transport around PSI and how cyclic electron transport is promoted during C4 evolution using studies on the genus Flaveria, which contains a number of closely related C3, C4 and C3-C4 intermediate species.
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Affiliation(s)
- Yuri Nakajima Munekage
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo, 669-1337 Japan
| | - Yukimi Y Taniguchi
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo, 669-1337 Japan
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Yamori W, Shikanai T. Physiological Functions of Cyclic Electron Transport Around Photosystem I in Sustaining Photosynthesis and Plant Growth. ANNUAL REVIEW OF PLANT BIOLOGY 2016; 67:81-106. [PMID: 26927905 DOI: 10.1146/annurev-arplant-043015-112002] [Citation(s) in RCA: 283] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The light reactions in photosynthesis drive both linear and cyclic electron transport around photosystem I (PSI). Linear electron transport generates both ATP and NADPH, whereas PSI cyclic electron transport produces ATP without producing NADPH. PSI cyclic electron transport is thought to be essential for balancing the ATP/NADPH production ratio and for protecting both photosystems from damage caused by stromal overreduction. Two distinct pathways of cyclic electron transport have been proposed in angiosperms: a major pathway that depends on the PROTON GRADIENT REGULATION 5 (PGR5) and PGR5-LIKE PHOTOSYNTHETIC PHENOTYPE 1 (PGRL1) proteins, which are the target site of antimycin A, and a minor pathway mediated by the chloroplast NADH dehydrogenase-like (NDH) complex. Recently, the regulation of PSI cyclic electron transport has been recognized as essential for photosynthesis and plant growth. In this review, we summarize the possible functions and importance of the two pathways of PSI cyclic electron transport.
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Affiliation(s)
- Wataru Yamori
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan;
- Precursory Research for Embryonic Science and Technology (PRESTO) and
| | - Toshiharu Shikanai
- Core Research for Evolutionary Science and Technology (CREST), Japan Science and Technology Agency, Kawaguchi 332-0012, Japan
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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Silveira JAG, Carvalho FEL. Proteomics, photosynthesis and salt resistance in crops: An integrative view. J Proteomics 2016; 143:24-35. [PMID: 26957143 DOI: 10.1016/j.jprot.2016.03.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 02/12/2016] [Accepted: 03/05/2016] [Indexed: 12/31/2022]
Abstract
Salinity is a stressful condition that causes a significant decrease in crop production worldwide. Salt stress affects several photosynthetic reactions, including the modulation of several important proteins. Despite these effects, few molecular-biochemical markers have been identified and evaluated for their importance in improving plant salt resistance. Proteomics is a powerful tool that allows the analysis of multigenic events at the post-translational level that has been widely used to evaluate protein modulation changes in plants exposed to salt stress. However, these studies are frequently fragmented and the results regarding photosynthesis proteins in response to salinity are limited. These constraints could be related to the low number of important photosynthetic proteins differently modulated in response to salinity, as has been commonly revealed by conventional proteomics. In this review, we present an evaluation and perspective on the integrated application of proteomics for the identification of photosynthesis proteins to improve salt resistance. We propose the use of phospho-, thiol- and redox-proteomics, associated with the utilization of isolated chloroplasts or photosynthetic sub-organellar components. This strategy may allow the characterization of essential proteins, providing a better understanding of photosynthesis regulation. Furthermore, this may contribute to the selection of molecular markers to improve salt resistance in crops.
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Affiliation(s)
- Joaquim A G Silveira
- Department of Biochemistry and Molecular Biology, Laboratory of Plant Metabolism, Federal University of Ceara, Fortaleza CEP 60451-970, Brazil.
| | - Fabricio E L Carvalho
- Department of Biochemistry and Molecular Biology, Laboratory of Plant Metabolism, Federal University of Ceara, Fortaleza CEP 60451-970, Brazil.
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Yamamoto H, Takahashi S, Badger MR, Shikanai T. Artificial remodelling of alternative electron flow by flavodiiron proteins in Arabidopsis. NATURE PLANTS 2016; 2:16012. [PMID: 27249347 DOI: 10.1038/nplants.2016.12] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 01/20/2016] [Indexed: 05/19/2023]
Abstract
In photosynthesis, linear electron transport from water to nicotinamide adenine dinucleotide phosphate (NADP(+)) cannot satisfy the ATP/NADPH production stoichiometry required by the Calvin-Benson cycle. Cyclic electron transport (CET) around photosystem I (PSI) and pseudocyclic electron transport (pseudoCET) can produce ATP without the accumulation of NADPH. Flavodiiron proteins (Flv) are the main mediator of pseudoCET in photosynthetic organisms, spanning cyanobacteria to gymnosperms. However, their genes are not conserved in angiosperms. Here we explore the possibility of complementing CET with Flv-dependent pseudoCET in the angiosperm Arabidopsis thaliana. We introduced FlvA and FlvB genes from the moss Physcomitrella patens into both wild-type (WT) Arabidopsis and the proton gradient regulation 5 (pgr5) mutant, which is defective in the main pathway of CET. We measured rates of pseudoCET using membrane inlet mass spectrometry, along with several photosynthetic parameters. Flv expression significantly increased rates of pseudoCET in the mutant plants, particularly at high light intensities, and partially restored the photosynthetic phenotype. In WT plants, Flv did not compete with PGR5-dependent CET during steady-state photosynthesis, but did form a large electron sink in fluctuating light. We conclude that flavodiiron proteins can help to protect the photosystems in Arabidopsis under fluctuating light, even in the presence of CET.
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Affiliation(s)
- Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan
- CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076, Japan
| | - Shunichi Takahashi
- Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Murray R Badger
- Australian Research Council Center of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan
- CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076, Japan
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