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Kunz HH, Armbruster U, Mühlbauer S, de Vries J, Davis GA. Chloroplast ion homeostasis - what do we know and where should we go? THE NEW PHYTOLOGIST 2024; 243:543-559. [PMID: 38515227 DOI: 10.1111/nph.19661] [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: 07/01/2023] [Accepted: 02/01/2024] [Indexed: 03/23/2024]
Abstract
Plant yields heavily depend on proper macro- and micronutrient supply from the soil. In the leaf cells, nutrient ions fulfill specific roles in biochemical reactions, especially photosynthesis housed in the chloroplast. Here, a well-balanced ion homeostasis is maintained by a number of ion transport proteins embedded in the envelope and thylakoid membranes. Ten years ago, the first alkali metal transporters from the K+ EFFLUX ANTIPORTER family were discovered in the model plant Arabidopsis. Since then, our knowledge about the physiological importance of these carriers and their substrates has greatly expanded. New insights into the role of alkali ions in plastid gene expression and photoprotective mechanisms, both prerequisites for plant productivity in natural environments, were gained. The discovery of a Cl- channel in the thylakoid and several additional plastid alkali and alkali metal transport proteins have advanced the field further. Nevertheless, scientists still have long ways to go before a complete systemic understanding of the chloroplast's ion transportome will emerge. In this Tansley review, we highlight and discuss the achievements of the last decade. More importantly, we make recommendations on what areas to prioritize, so the field can reach the next milestones. One area, laid bare by our similarity-based comparisons among phototrophs is our lack of knowledge what ion transporters are used by cyanobacteria to buffer photosynthesis fluctuations.
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Affiliation(s)
- Hans-Henning Kunz
- Plant Biochemistry, Biology, LMU Munich, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
| | - Ute Armbruster
- Institute of Molecular Photosynthesis, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
- CEPLAS - Cluster of Excellence on Plant Sciences, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Susanne Mühlbauer
- Plant Biochemistry, Biology, LMU Munich, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
| | - Jan de Vries
- Department of Applied Bioinformatics, Institute for Microbiology and Genetics, Goettingen Center for Molecular Biosciences (GZMB), Campus Institute Data Science (CIDAS), University of Goettingen, Goldschmidtstr. 1, D-37077, Göttingen, Germany
| | - Geoffry A Davis
- Plant Biochemistry, Biology, LMU Munich, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
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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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Stirbet A, Guo Y, Lazár D, Govindjee G. From leaf to multiscale models of photosynthesis: applications and challenges for crop improvement. PHOTOSYNTHESIS RESEARCH 2024:10.1007/s11120-024-01083-9. [PMID: 38619700 DOI: 10.1007/s11120-024-01083-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 01/29/2024] [Indexed: 04/16/2024]
Abstract
To keep up with the growth of human population and to circumvent deleterious effects of global climate change, it is essential to enhance crop yield to achieve higher production. Here we review mathematical models of oxygenic photosynthesis that are extensively used, and discuss in depth a subset that accounts for diverse approaches providing solutions to our objective. These include models (1) to study different ways to enhance photosynthesis, such as fine-tuning antenna size, photoprotection and electron transport; (2) to bioengineer carbon metabolism; and (3) to evaluate the interactions between the process of photosynthesis and the seasonal crop dynamics, or those that have included statistical whole-genome prediction methods to quantify the impact of photosynthesis traits on the improvement of crop yield. We conclude by emphasizing that the results obtained in these studies clearly demonstrate that mathematical modelling is a key tool to examine different approaches to improve photosynthesis for better productivity, while effective multiscale crop models, especially those that also include remote sensing data, are indispensable to verify different strategies to obtain maximized crop yields.
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Affiliation(s)
| | - Ya Guo
- Key Laboratory of Advanced Process Control for Light Industry, Ministry of Education Jiangnan University, Wuxi, 214122, China
| | - Dušan Lazár
- Department of Biophysics, Faculty of Science, Palacký Univesity, Šlechtitelů 27, 78371, Olomouc, Czech Republic
| | - Govindjee Govindjee
- Department of Biochemistry, Department of Plant Biology, and the Center of Biophysics & Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
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4
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Tóth D, Kuntam S, Ferenczi Á, Vidal-Meireles A, Kovács L, Wang L, Sarkadi Z, Migh E, Szentmihályi K, Tengölics R, Neupert J, Bock R, Jonikas MC, Molnar A, Tóth SZ. Chloroplast phosphate transporter CrPHT4-7 regulates phosphate homeostasis and photosynthesis in Chlamydomonas. PLANT PHYSIOLOGY 2024; 194:1646-1661. [PMID: 37962583 PMCID: PMC10904345 DOI: 10.1093/plphys/kiad607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/18/2023] [Accepted: 10/19/2023] [Indexed: 11/15/2023]
Abstract
In eukaryotic cells, phosphorus is assimilated and utilized primarily as phosphate (Pi). Pi homeostasis is mediated by transporters that have not yet been adequately characterized in green algae. This study reports on PHOSPHATE TRANSPORTER 4-7 (CrPHT4-7) from Chlamydomonas reinhardtii, a member of the PHT4 transporter family, which exhibits remarkable similarity to AtPHT4;4 from Arabidopsis (Arabidopsis thaliana), a chloroplastic ascorbate transporter. Using fluorescent protein tagging, we show that CrPHT4-7 resides in the chloroplast envelope membrane. Crpht4-7 mutants, generated by the CRISPR/Cas12a-mediated single-strand templated repair, show retarded growth, especially in high light, reduced ATP level, strong ascorbate accumulation, and diminished non-photochemical quenching in high light. On the other hand, total cellular phosphorous content was unaffected, and the phenotype of the Crpht4-7 mutants could not be alleviated by ample Pi supply. CrPHT4-7-overexpressing lines exhibit enhanced biomass accumulation under high light conditions in comparison with the wild-type strain. Expressing CrPHT4-7 in a yeast (Saccharomyces cerevisiae) strain lacking Pi transporters substantially recovered its slow growth phenotype, demonstrating that CrPHT4-7 transports Pi. Even though CrPHT4-7 shows a high degree of similarity to AtPHT4;4, it does not display any substantial ascorbate transport activity in yeast or intact algal cells. Thus, the results demonstrate that CrPHT4-7 functions as a chloroplastic Pi transporter essential for maintaining Pi homeostasis and photosynthesis in C. reinhardtii.
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Affiliation(s)
- Dávid Tóth
- Institute of Plant Biology, HUN-REN Biological Research Centre, H-6726 Szeged, Hungary
- Doctoral School of Biology, University of Szeged, H-6722 Szeged, Hungary
| | - Soujanya Kuntam
- Institute of Plant Biology, HUN-REN Biological Research Centre, H-6726 Szeged, Hungary
| | - Áron Ferenczi
- Institute of Molecular Plant Sciences, School of Biological Sciences, King's Buildings, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - André Vidal-Meireles
- Institute of Plant Biology, HUN-REN Biological Research Centre, H-6726 Szeged, Hungary
| | - László Kovács
- Institute of Plant Biology, HUN-REN Biological Research Centre, H-6726 Szeged, Hungary
| | - Lianyong Wang
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Princeton, NJ 08544, USA
| | - Zsuzsa Sarkadi
- Institute of Biochemistry, HUN-REN Biological Research Centre, H-6726 Szeged, Hungary
- Hungarian Centre of Excellence for Molecular Medicine—Biological Research Centre Metabolic Systems Biology Research Group, H-6726 Szeged, Hungary
| | - Ede Migh
- Institute of Biochemistry, HUN-REN Biological Research Centre, H-6726 Szeged, Hungary
| | - Klára Szentmihályi
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, H-1117 Budapest, Hungary
| | - Roland Tengölics
- Hungarian Centre of Excellence for Molecular Medicine—Biological Research Centre Metabolic Systems Biology Research Group, H-6726 Szeged, Hungary
- Metabolomics Lab, Core Facilities, HUN-REN Biological Research Centre, H-6726 Szeged, Hungary
| | - Juliane Neupert
- Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany
| | - Ralph Bock
- Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany
| | - Martin C Jonikas
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Princeton, NJ 08544, USA
- Howard Hughes Medical Institute, Princeton University, Lewis Thomas Laboratory, Princeton, NJ 08544, USA
| | - Attila Molnar
- Institute of Molecular Plant Sciences, School of Biological Sciences, King's Buildings, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Szilvia Z Tóth
- Institute of Plant Biology, HUN-REN Biological Research Centre, H-6726 Szeged, Hungary
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Maekawa S, Ohnishi M, Wada S, Ifuku K, Miyake C. Enhanced Reduction of Ferredoxin in PGR5-Deficient Mutant of Arabidopsis thaliana Stimulated Ferredoxin-Dependent Cyclic Electron Flow around Photosystem I. Int J Mol Sci 2024; 25:2677. [PMID: 38473924 DOI: 10.3390/ijms25052677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 02/12/2024] [Accepted: 02/25/2024] [Indexed: 03/14/2024] Open
Abstract
The molecular entity responsible for catalyzing ferredoxin (Fd)-dependent cyclic electron flow around photosystem I (Fd-CEF) remains unidentified. To reveal the in vivo molecular mechanism of Fd-CEF, evaluating ferredoxin reduction-oxidation kinetics proves to be a reliable indicator of Fd-CEF activity. Recent research has demonstrated that the expression of Fd-CEF activity is contingent upon the oxidation of plastoquinone. Moreover, chloroplast NAD(P)H dehydrogenase does not catalyze Fd-CEF in Arabidopsis thaliana. In this study, we analyzed the impact of reduced Fd on Fd-CEF activity by comparing wild-type and pgr5-deficient mutants (pgr5hope1). PGR5 has been proposed as the mediator of Fd-CEF, and pgr5hope1 exhibited a comparable CO2 assimilation rate and the same reduction-oxidation level of PQ as the wild type. However, P700 oxidation was suppressed with highly reduced Fd in pgr5hope1, unlike in the wild type. As anticipated, the Fd-CEF activity was enhanced in pgr5hope1 compared to the wild type, and its activity further increased with the oxidation of PQ due to the elevated CO2 assimilation rate. This in vivo research clearly demonstrates that the expression of Fd-CEF activity requires not only reduced Fd but also oxidized PQ. Importantly, PGR5 was found to not catalyze Fd-CEF, challenging previous assumptions about its role in this process.
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Affiliation(s)
- Shu Maekawa
- Graduate School for Agricultural Science, Kobe University, 1-1 Rokkodai, Nada-Ku, Kobe 657-8501, Japan
| | - Miho Ohnishi
- Graduate School for Agricultural Science, Kobe University, 1-1 Rokkodai, Nada-Ku, Kobe 657-8501, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 7 Gobancho, Kyoto 606-8502, Japan
| | - Shinya Wada
- Graduate School for Agricultural Science, Kobe University, 1-1 Rokkodai, Nada-Ku, Kobe 657-8501, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 7 Gobancho, Kyoto 606-8502, Japan
| | - Kentaro Ifuku
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 7 Gobancho, Kyoto 606-8502, Japan
- Graduate School for Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Chikahiro Miyake
- Graduate School for Agricultural Science, Kobe University, 1-1 Rokkodai, Nada-Ku, Kobe 657-8501, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 7 Gobancho, Kyoto 606-8502, Japan
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6
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Mahapatra K, Mukherjee A, Suyal S, Dar MA, Bhagavatula L, Datta S. Regulation of chloroplast biogenesis, development, and signaling by endogenous and exogenous cues. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2024; 30:167-183. [PMID: 38623168 PMCID: PMC11016055 DOI: 10.1007/s12298-024-01427-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 02/07/2024] [Accepted: 02/27/2024] [Indexed: 04/17/2024]
Abstract
Chloroplasts are one of the defining features in most plants, primarily known for their unique property to carry out photosynthesis. Besides this, chloroplasts are also associated with hormone and metabolite productions. For this, biogenesis and development of chloroplast are required to be synchronized with the seedling growth to corroborate the maximum rate of photosynthesis following the emergence of seedlings. Chloroplast biogenesis and development are dependent on the signaling to and from the chloroplast, which are in turn regulated by several endogenous and exogenous cues. Light and hormones play a crucial role in chloroplast maturation and development. Chloroplast signaling involves a coordinated two-way connection between the chloroplast and nucleus, termed retrograde and anterograde signaling, respectively. Anterograde and retrograde signaling are involved in regulation at the transcriptional level and downstream modifications and are modulated by several metabolic and external cues. The communication between chloroplast and nucleus is essential for plants to develop strategies to cope with various stresses including high light or high heat. In this review, we have summarized several aspects of chloroplast development and its regulation through the interplay of various external and internal factors. We have also discussed the involvement of chloroplasts as sensors of various external environment stress factors including high light and temperature, and communicate via a series of retrograde signals to the nucleus, thus playing an essential role in plants' abiotic stress response.
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Affiliation(s)
- Kalyan Mahapatra
- Plant Cell and Developmental Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, Madhya Pradesh 462066 India
| | - Arpan Mukherjee
- Plant Cell and Developmental Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, Madhya Pradesh 462066 India
| | - Shikha Suyal
- Plant Cell and Developmental Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, Madhya Pradesh 462066 India
| | - Mansoor Ali Dar
- Plant Cell and Developmental Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, Madhya Pradesh 462066 India
| | | | - Sourav Datta
- Plant Cell and Developmental Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, Madhya Pradesh 462066 India
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7
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Walker BJ, Driever SM, Kromdijk J, Lawson T, Busch FA. Tools for Measuring Photosynthesis at Different Scales. Methods Mol Biol 2024; 2790:1-26. [PMID: 38649563 DOI: 10.1007/978-1-0716-3790-6_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Measurements of in vivo photosynthesis are powerful tools that probe the largest fluxes of carbon and energy in an illuminated leaf, but often the specific techniques used are so varied and specialized that it is difficult for researchers outside the field to select and perform the most useful assays for their research questions. The goal of this chapter is to provide a broad overview of the current tools available for the study of photosynthesis, both in vivo and in vitro, so as to provide a foundation for selecting appropriate techniques, many of which are presented in detail in subsequent chapters. This chapter will also organize current methods into a comparative framework and provide examples of how they have been applied to research questions of broad agronomical, ecological, or biological importance. This chapter closes with an argument that the future of in vivo measurements of photosynthesis lies in the ability to use multiple methods simultaneously and discusses the benefits of this approach to currently open physiological questions. This chapter, combined with the relevant methods chapters, could serve as a laboratory course in methods in photosynthesis research or as part of a more comprehensive laboratory course in general plant physiology methods.
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Affiliation(s)
- Berkley J Walker
- Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
| | - Steven M Driever
- Centre for Crop Systems Analysis, Wageningen University and Research, Wageningen, The Netherlands
| | - Johannes Kromdijk
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, USA
| | - Tracy Lawson
- School of Life Sciences, University of Essex, Colchester, UK
| | - Florian A Busch
- School of Biosciences and The Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK.
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8
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Adler L, Lau CS, Shaikh KM, van Maldegem KA, Payne-Dwyer AL, Lefoulon C, Girr P, Atkinson N, Barrett J, Emrich-Mills TZ, Dukic E, Blatt MR, Leake MC, Peltier G, Spetea C, Burlacot A, McCormick AJ, Mackinder LCM, Walker CE. The role of BST4 in the pyrenoid of Chlamydomonas reinhardtii. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.15.545204. [PMID: 38014171 PMCID: PMC10680556 DOI: 10.1101/2023.06.15.545204] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
In many eukaryotic algae, CO2 fixation by Rubisco is enhanced by a CO2-concentrating mechanism, which utilizes a Rubisco-rich organelle called the pyrenoid. The pyrenoid is traversed by a network of thylakoid-membranes called pyrenoid tubules, proposed to deliver CO2. In the model alga Chlamydomonas reinhardtii (Chlamydomonas), the pyrenoid tubules have been proposed to be tethered to the Rubisco matrix by a bestrophin-like transmembrane protein, BST4. Here, we show that BST4 forms a complex that localizes to the pyrenoid tubules. A Chlamydomonas mutant impaired in the accumulation of BST4 (bst4) formed normal pyrenoid tubules and heterologous expression of BST4 in Arabidopsis thaliana did not lead to the incorporation of thylakoids into a reconstituted Rubisco condensate. Chlamydomonas bst4 mutant did not show impaired growth at air level CO2. By quantifying the non-photochemical quenching (NPQ) of chlorophyll fluorescence, we show that bst4 displays a transiently lower thylakoid lumenal pH during dark to light transition compared to control strains. When acclimated to high light, bst4 had sustained higher NPQ and elevated levels of light-induced H2O2 production. We conclude that BST4 is not a tethering protein, but rather is an ion channel involved in lumenal pH regulation possibly by mediating bicarbonate transport across the pyrenoid tubules.
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Affiliation(s)
- Liat Adler
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, EH9 3BF, United Kingdom
- Centre for Engineering Biology, University of Edinburgh, EH9 3BF, United Kingdom
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA, 94305 USA
| | - Chun Sing Lau
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Kashif M Shaikh
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Kim A van Maldegem
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Alex L Payne-Dwyer
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
- School of Physics, Engineering and Technology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Cecile Lefoulon
- Laboratory of Plant Physiology and Biophysics, Bower Building, University of Glasgow, Glasgow, United Kingdom
| | - Philipp Girr
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Nicky Atkinson
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, EH9 3BF, United Kingdom
- Centre for Engineering Biology, University of Edinburgh, EH9 3BF, United Kingdom
| | - James Barrett
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Tom Z Emrich-Mills
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Emilija Dukic
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Michael R Blatt
- Laboratory of Plant Physiology and Biophysics, Bower Building, University of Glasgow, Glasgow, United Kingdom
| | - Mark C Leake
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
- School of Physics, Engineering and Technology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Gilles Peltier
- Aix-Marseille Université, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache, 13108 Saint-Paul-lez-Durance, France
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Adrien Burlacot
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA, 94305 USA
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
| | - Alistair J McCormick
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, EH9 3BF, United Kingdom
- Centre for Engineering Biology, University of Edinburgh, EH9 3BF, United Kingdom
| | - Luke C M Mackinder
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Charlotte E Walker
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
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9
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Zhou W, Hao B, Bricker TM, Theg SM. A real-time analysis of protein transport via the twin arginine translocation pathway in response to different components of the protonmotive force. J Biol Chem 2023; 299:105286. [PMID: 37742925 PMCID: PMC10641609 DOI: 10.1016/j.jbc.2023.105286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 08/28/2023] [Accepted: 09/18/2023] [Indexed: 09/26/2023] Open
Abstract
The twin arginine translocation (Tat) pathway transports folded protein across the cytoplasmic membrane in bacteria, archaea, and across the thylakoid membrane in plants as well as the inner membrane in some mitochondria. In plant chloroplasts, the Tat pathway utilizes the protonmotive force (PMF) to drive protein translocation. However, in bacteria, it has been shown that Tat transport depends only on the transmembrane electrical potential (Δψ) component of PMF in vitro. To investigate the comprehensive PMF requirement in Escherichia coli, we have developed the first real-time assay to monitor Tat transport utilizing the NanoLuc Binary Technology in E. coli spheroplasts. This luminescence assay allows for continuous monitoring of Tat transport with high-resolution, making it possible to observe subtle changes in transport in response to different treatments. By applying the NanoLuc assay, we report that, under acidic conditions (pH = 6.3), ΔpH, in addition to Δψ, contributes energetically to Tat transport in vivo in E. coli spheroplasts. These results provide novel insight into the mechanism of energy utilization by the Tat pathway.
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Affiliation(s)
- Wenjie Zhou
- Department of Plant Biology, University of California, Davis, California, USA
| | - Binhan Hao
- Department of Plant Biology, University of California, Davis, California, USA
| | - Terry M Bricker
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Steven M Theg
- Department of Plant Biology, University of California, Davis, California, USA.
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10
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Semenov AY, Tikhonov AN. Electrometric and Electron Paramagnetic Resonance Measurements of a Difference in the Transmembrane Electrochemical Potential: Photosynthetic Subcellular Structures and Isolated Pigment-Protein Complexes. MEMBRANES 2023; 13:866. [PMID: 37999352 PMCID: PMC10673362 DOI: 10.3390/membranes13110866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/23/2023] [Accepted: 10/26/2023] [Indexed: 11/25/2023]
Abstract
A transmembrane difference in the electrochemical potentials of protons (ΔμH+) serves as a free energy intermediate in energy-transducing organelles of the living cell. The contributions of two components of the ΔμH+ (electrical, Δψ, and concentrational, ΔpH) to the overall ΔμH+ value depend on the nature and lipid composition of the energy-coupling membrane. In this review, we briefly consider several of the most common instrumental (electrometric and EPR) methods for numerical estimations of Δψ and ΔpH. In particular, the kinetics of the flash-induced electrometrical measurements of Δψ in bacterial chromatophores, isolated bacterial reaction centers, and Photosystems I and II of the oxygenic photosynthesis, as well as the use of pH-sensitive molecular indicators and kinetic data regarding pH-dependent electron transport in chloroplasts, have been reviewed. Further perspectives on the application of these methods to solve some fundamental and practical problems of membrane bioenergetics are discussed.
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Affiliation(s)
- Alexey Yu. Semenov
- A.N. Belozersky Institute of Physical-Chemical Biology, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia;
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11
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Dukic E, van Maldegem KA, Shaikh KM, Fukuda K, Töpel M, Solymosi K, Hellsten J, Hansen TH, Husted S, Higgins J, Sano S, Ishijima S, Spetea C. Chloroplast magnesium transporters play essential but differential roles in maintaining magnesium homeostasis. FRONTIERS IN PLANT SCIENCE 2023; 14:1221436. [PMID: 37692441 PMCID: PMC10484576 DOI: 10.3389/fpls.2023.1221436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 07/07/2023] [Indexed: 09/12/2023]
Abstract
Magnesium (Mg2+) is essential for photosynthesis in the chloroplasts of land plants and algae. Being the central ion of chlorophyll, cofactor and activator of many photosynthetic enzymes including RuBisCO, magnesium-deficient plants may suffer from leaf chlorosis symptoms and retarded growth. Therefore, the chloroplast Mg2+ concentration is tightly controlled by magnesium transport proteins. Recently, three different transporters from two distinct families have been identified in the chloroplast inner envelope of the model plant Arabidopsis thaliana: MGT10, MGR8, and MGR9. Here, we assess the individual roles of these three proteins in maintaining chloroplast Mg2+ homeostasis and regulating photosynthesis, and if their role is conserved in the model green alga Chlamydomonas reinhardtii. Phylogenetic analysis and heterologous expression revealed that the CorC-like MGR8 and MGR9 transport Mg2+ by a different mechanism than the CorA-like MGT10. MGR8 and MGT10 genes are highest expressed in leaves, indicating a function in chloroplast Mg2+ transport. MGR9 is important for chloroplast function and plant adaptation in conditions of deficiency or excess of Mg2+. Transmission electron microscopy indicated that MGT10 plays a differential role in thylakoid stacking than MGR8 and MGR9. Furthermore, we report that MGR8, MGR9, and MGT10 are involved in building up the pH gradient across the thylakoid membrane and activating photoprotection in conditions of excess light, however the mechanism has not been resolved yet. While there are no chloroplast MGR-like transporters in Chlamydomonas, we show that MRS4 is a homolog of MGT10, that is required for photosynthesis and cell growth. Taken together, our findings reveal that the studied Mg2+ transporters play essential but differential roles in maintaining chloroplast Mg2+ homeostasis.
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Affiliation(s)
- Emilija Dukic
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Kim A. van Maldegem
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Kashif Mohd Shaikh
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Kento Fukuda
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Mats Töpel
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
- IVL Swedish Environmental Research Institute, Gothenburg, Sweden
| | - Katalin Solymosi
- Department of Plant Anatomy, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Jonna Hellsten
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Thomas Hesselhøj Hansen
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Søren Husted
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - John Higgins
- Department of Geosciences, Princeton University, Princeton, NJ, United States
| | - Satoshi Sano
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Sumio Ishijima
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
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12
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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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13
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Mattila H, Tyystjärvi E. Red pigments in autumn leaves of Norway maple do not offer significant photoprotection but coincide with stress symptoms. TREE PHYSIOLOGY 2023; 43:751-768. [PMID: 36715646 PMCID: PMC10177003 DOI: 10.1093/treephys/tpad010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 01/13/2023] [Accepted: 01/25/2023] [Indexed: 05/13/2023]
Abstract
The reasons behind autumn colors, a striking manifestation of anthocyanin synthesis in plants, are poorly understood. Usually, not all leaves of an anthocyanic plant turn red or only a part of the leaf blade turns red. In the present study, we compared green, red and yellow sections of senescing Norway maple leaves, asking if red pigments offer photoprotection, and if so, whether the protection benefits the senescing tree. Green and senescing maple leaves were illuminated with strong white, green or red light in the absence or presence of lincomycin which blocks photosystem II (PSII) repair. Irrespective of the presence of anthocyanins, senescing leaves showed weaker capacity to repair PSII than green leaves. Furthermore, the rate of photoinhibition of PSII did not significantly differ between red and yellow sections of senescing maple leaves. We also followed pigment contents and photosynthetic reactions in individual leaves, from the end of summer until abscission of the leaf. In maple, red pigments accumulated only during late senescence, but light reactions stayed active until most of the chlorophyll had been degraded. PSII activity was found to be lower and non-photochemical quenching higher in red leaf sections, compared with yellow sections of senescing leaves. Red leaf sections were also thicker. We suggest that the primary function of anthocyanin synthesis is not to protect senescing leaves from excess light but to dispose of carbohydrates. This would relieve photosynthetic control, allowing the light reactions to produce energy for nutrient translocation at the last phase of autumn senescence when carbon skeletons are no longer needed.
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Affiliation(s)
- Heta Mattila
- Department of Life Technologies/Molecular Plant Biology, University of Turku, 20014 Turku, Finland
- Centre for Environmental and Marine Studies (CESAM), Department of Biology, University of Aveiro, Portugal
| | - Esa Tyystjärvi
- Department of Life Technologies/Molecular Plant Biology, University of Turku, 20014 Turku, Finland
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14
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Yue X, Ke X, Shi Y, Li Y, Zhang C, Wang Y, Hou X. Chloroplast inner envelope protein FtsH11 is involved in the adjustment of assembly of chloroplast ATP synthase under heat stress. PLANT, CELL & ENVIRONMENT 2023; 46:850-864. [PMID: 36573466 DOI: 10.1111/pce.14525] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 12/08/2022] [Accepted: 12/11/2022] [Indexed: 06/17/2023]
Abstract
The maintenance of a proton gradient across the thylakoid membrane is an integral aspect of photosynthesis that is mainly established by the splitting of water molecules in photosystem II and plastoquinol oxidation at the cytochrome complex, and it is necessary for the generation of ATP in the last step of photophosphorylation. Although environmental stresses, such as high temperatures, are known to disrupt this fundamental process, only a few studies have explored the molecular mechanisms underlying proton gradient regulation during stress. The present study identified a heat-sensitive mutant that displays aberrant photosynthesis at high temperatures. This mutation was mapped to AtFtsH11, which encodes an ATP-dependent AAA-family metalloprotease. We showed that AtFtsH11 localizes to the chloroplast inner envelope membrane and is capable of degrading the ATP synthase assembly factor BFA3 under heat stress. We posit that this function limits the amount of ATP synthase integrated into the thylakoid membrane to regulate proton efflux from the lumen to the stroma. Our data also suggest that AtFtsH11 is critical in stabilizing photosystem II and cytochrome complexes at high temperatures, and additional studies can further elucidate the specific molecular functions of this critical regulator of photosynthetic thermotolerance.
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Affiliation(s)
- Xiaohong Yue
- State Key Laboratory of Hybrid Rice, Hubei Hongshan Laboratory, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiangsheng Ke
- State Key Laboratory of Hybrid Rice, Hubei Hongshan Laboratory, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yafei Shi
- State Key Laboratory of Hybrid Rice, Hubei Hongshan Laboratory, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yangsheng Li
- State Key Laboratory of Hybrid Rice, Hubei Hongshan Laboratory, College of Life Sciences, Wuhan University, Wuhan, China
| | - Chenhao Zhang
- State Key Laboratory of Hybrid Rice, Hubei Hongshan Laboratory, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yetao Wang
- State Key Laboratory of Hybrid Rice, Hubei Hongshan Laboratory, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xin Hou
- State Key Laboratory of Hybrid Rice, Hubei Hongshan Laboratory, College of Life Sciences, Wuhan University, Wuhan, China
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15
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Hao B, Zhou W, Theg SM. The polar amino acid in the TatA transmembrane helix is not strictly necessary for protein function. J Biol Chem 2023; 299:102998. [PMID: 36764519 PMCID: PMC10124905 DOI: 10.1016/j.jbc.2023.102998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 01/29/2023] [Accepted: 02/01/2023] [Indexed: 02/11/2023] Open
Abstract
The twin-arginine translocation (Tat) pathway utilizes the proton-motive force (pmf) to transport folded proteins across cytoplasmic membranes in bacteria and archaea, as well as across the thylakoid membrane in plants and the inner membrane in mitochondria. In most species, the minimal components required for Tat activity consist of three subunits, TatA, TatB, and TatC. Previous studies have shown that a polar amino acid is present at the N-terminus of the TatA transmembrane helix (TMH) across many different species. In order to systematically assess the functional importance of this polar amino acid in the TatA TMH in Escherichia coli, we examined a complete set of 19-amino-acid substitutions. Unexpectedly, although being preferred overall, our experiments suggest that the polar amino acid is not necessary for a functional TatA. Hydrophilicity and helix-stabilizing properties of this polar amino acid were found to be highly correlated with the Tat activity. Specifically, change in charge status of the amino acid side chain due to pH resulted in a shift in hydrophilicity, which was demonstrated to impact the Tat transport activity. Furthermore, we identified a four-residue motif at the N-terminus of the TatA TMH by sequence alignment. Using a biochemical approach, we found that the N-terminal motif was functionally significant, with evidence indicating a potential role in the preference for utilizing different pmf components. Taken together, these findings yield new insights into the functionality of TatA and its potential role in the Tat transport mechanism.
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Affiliation(s)
- Binhan Hao
- Plant Biology Department, University of California, Davis, California, USA
| | - Wenjie Zhou
- Plant Biology Department, University of California, Davis, California, USA
| | - Steven M Theg
- Plant Biology Department, University of California, Davis, California, USA.
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16
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Strand DD, Walker BJ. Energetic considerations for engineering novel biochemistries in photosynthetic organisms. FRONTIERS IN PLANT SCIENCE 2023; 14:1116812. [PMID: 36814754 PMCID: PMC9939686 DOI: 10.3389/fpls.2023.1116812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 01/23/2023] [Indexed: 06/18/2023]
Abstract
Humans have been harnessing biology to make valuable compounds for generations. From beer and biofuels to pharmaceuticals, biology provides an efficient alternative to industrial processes. With the continuing advancement of molecular tools to genetically modify organisms, biotechnology is poised to solve urgent global problems related to environment, increasing population, and public health. However, the light dependent reactions of photosynthesis are constrained to produce a fixed stoichiometry of ATP and reducing equivalents that may not match the newly introduced synthetic metabolism, leading to inefficiency or damage. While photosynthetic organisms have evolved several ways to modify the ATP/NADPH output from their thylakoid electron transport chain, it is unknown if the native energy balancing mechanisms grant enough flexibility to match the demands of the synthetic metabolism. In this review we discuss the role of photosynthesis in the biotech industry, and the energetic considerations of using photosynthesis to power synthetic biology.
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Affiliation(s)
- Deserah D. Strand
- U. S. Department of Energy (DOE) Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
| | - Berkley J. Walker
- U. S. Department of Energy (DOE) Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
- Department of Plant Biology, Michigan State University, East Lansing, MI, United States
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17
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Reiter B, Rosenhammer L, Marino G, Geimer S, Leister D, Rühle T. CGL160-mediated recruitment of the coupling factor CF1 is required for efficient thylakoid ATP synthase assembly, photosynthesis, and chloroplast development in Arabidopsis. THE PLANT CELL 2023; 35:488-509. [PMID: 36250886 PMCID: PMC9806626 DOI: 10.1093/plcell/koac306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 09/25/2022] [Indexed: 06/16/2023]
Abstract
Chloroplast ATP synthases consist of a membrane-spanning coupling factor (CFO) and a soluble coupling factor (CF1). It was previously demonstrated that CONSERVED ONLY IN THE GREEN LINEAGE160 (CGL160) promotes the formation of plant CFO and performs a similar function in the assembly of its c-ring to that of the distantly related bacterial Atp1/UncI protein. Here, we show that in Arabidopsis (Arabidopsis thaliana) the N-terminal portion of CGL160 (AtCGL160N) is required for late steps in CF1-CFO assembly. In plants that lacked AtCGL160N, CF1-CFO content, photosynthesis, and chloroplast development were impaired. Loss of AtCGL160N did not perturb c-ring formation, but led to a 10-fold increase in the numbers of stromal CF1 subcomplexes relative to that in the wild type. Co-immunoprecipitation and protein crosslinking assays revealed an association of AtCGL160 with CF1 subunits. Yeast two-hybrid assays localized the interaction to a stretch of AtCGL160N that binds to the DELSEED-containing CF1-β subdomain. Since Atp1 of Synechocystis (Synechocystis sp. PCC 6803) could functionally replace the membrane domain of AtCGL160 in Arabidopsis, we propose that CGL160 evolved from a cyanobacterial ancestor and acquired an additional function in the recruitment of a soluble CF1 subcomplex, which is critical for the modulation of CF1-CFO activity and photosynthesis.
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Affiliation(s)
- Bennet Reiter
- Plant Molecular Biology Faculty of Biology I, Ludwig-Maximilians-Universität Munich, D-82152 Planegg-Martinsried, Germany
| | - Lea Rosenhammer
- Plant Molecular Biology Faculty of Biology I, Ludwig-Maximilians-Universität Munich, D-82152 Planegg-Martinsried, Germany
| | - Giada Marino
- Plant Molecular Biology Faculty of Biology I, Ludwig-Maximilians-Universität Munich, D-82152 Planegg-Martinsried, Germany
| | - Stefan Geimer
- Zellbiologie/Elektronenmikroskopie NW I/B1, Universität Bayreuth, 95447 Bayreuth, Germany
| | - Dario Leister
- Plant Molecular Biology Faculty of Biology I, Ludwig-Maximilians-Universität Munich, D-82152 Planegg-Martinsried, Germany
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18
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Lyu H, Lazár D. Effect of ion fluxes on regulating the light-induced transthylakoid electric potential difference. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 194:60-69. [PMID: 36379178 DOI: 10.1016/j.plaphy.2022.10.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/11/2022] [Accepted: 10/29/2022] [Indexed: 06/16/2023]
Abstract
The light-induced transthylakoid membrane potential (ΔΨ) can not only drive the ATP synthesis through the ATP-synthase in chloroplasts but serve as an essential modifier in the acclimation of photosynthesis to fluctuating light conditions. It has been manifested that during photosynthesis, the light-induced ΔΨ is responsive to multiple factors among which the ion channels/transporters (e.g., V-K+, VCCN1, and KEA3) are key to adjust the ion distribution on the two sides of the thylakoid membrane and hence shape the kinetics of ΔΨ. However, an in-depth mechanistic understanding of ion fluxes on adjusting the transthylakoid electric potentials is still unclear. This lack of a mechanistic understanding is due to the experimental difficulty of closely observing ion fluxes in vivo and also hacking the evolution of parameters in a highly intertwined photosynthetic network. In this work, a computer model was applied to investigate the roles of ion fluxes on adjusting transthylakoid electric potentials upon a temporal cycle of a period of high illumination followed by a dark-adapted phase. The computing data revealed that, firstly, upon illumination, the dissipation of the steady-ΔΨ by ∼10 mV is contributed from the V-K+-driven K+ flux whilst ∼8 mV of the steady-ΔΨ is dissipated by the VCCN1-pumped Cl- flux, but there were no appreciable KEA3-evoked variations on ΔΨ; secondly, on transition from high light to darkness, V-K+ and KEA3 are serving as major contributors whereas VCCN1 taking a counterbalancing part in shaping a standard trace of ECS (electrochromic shift), which commonly shows a sharp fall to a minimum before returning to the baseline in darkness. Besides, the functional consequences on components of ΔΨ adjusted by every particular ion channel/transporter were also explored. By employing the model, we bring evidence that particular thylakoid-harbored proteins, namely V-K+, VCCN1, and KEA3, function by distinct mechanisms in the dynamic adjustment of electric potential, which might be mainly importnat under fluctuating light conditions.
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Affiliation(s)
- Hui Lyu
- School of Biological Science and Agriculture, Qiannan Normal University for Nationalities, Duyun, China.
| | - Dušan Lazár
- Department of Biophysics, Faculty of Science, Palacký University, Olomouc, Czech Republic.
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19
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von Bismarck T, Korkmaz K, Ruß J, Skurk K, Kaiser E, Correa Galvis V, Cruz JA, Strand DD, Köhl K, Eirich J, Finkemeier I, Jahns P, Kramer DM, Armbruster U. Light acclimation interacts with thylakoid ion transport to govern the dynamics of photosynthesis in Arabidopsis. THE NEW PHYTOLOGIST 2023; 237:160-176. [PMID: 36378135 DOI: 10.1111/nph.18534] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
Understanding photosynthesis in natural, dynamic light environments requires knowledge of long-term acclimation, short-term responses, and their mechanistic interactions. To approach the latter, we systematically determined and characterized light-environmental effects on thylakoid ion transport-mediated short-term responses during light fluctuations. For this, Arabidopsis thaliana wild-type and mutants of the Cl- channel VCCN1 and the K+ exchange antiporter KEA3 were grown under eight different light environments and characterized for photosynthesis-associated parameters and factors in steady state and during light fluctuations. For a detailed characterization of selected light conditions, we monitored ion flux dynamics at unprecedented high temporal resolution by a modified spectroscopy approach. Our analyses reveal that daily light intensity sculpts photosynthetic capacity as a main acclimatory driver with positive and negative effects on the function of KEA3 and VCCN1 during high-light phases, respectively. Fluctuations in light intensity boost the accumulation of the photoprotective pigment zeaxanthin (Zx). We show that KEA3 suppresses Zx accumulation during the day, which together with its direct proton transport activity accelerates photosynthetic transition to lower light intensities. In summary, both light-environment factors, intensity and variability, modulate the function of thylakoid ion transport in dynamic photosynthesis with distinct effects on lumen pH, Zx accumulation, photoprotection, and photosynthetic efficiency.
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Affiliation(s)
| | - Kübra Korkmaz
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Jeremy Ruß
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Kira Skurk
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Elias Kaiser
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | | | - Jeffrey A Cruz
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Deserah D Strand
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Karin Köhl
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Jürgen Eirich
- Plant Physiology, Institute of Plant Biology and Biotechnology, University of Münster, 48149, Münster, Germany
| | - Iris Finkemeier
- Plant Physiology, Institute of Plant Biology and Biotechnology, University of Münster, 48149, Münster, Germany
| | - Peter Jahns
- Plant Biochemistry, Heinrich-Heine-University Düsseldorf, 40225, Düsseldorf, Germany
| | - David M Kramer
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Ute Armbruster
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
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20
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Dukic E, Gollan PJ, Grebe S, Paakkarinen V, Herdean A, Aro EM, Spetea C. The Arabidopsis thylakoid chloride channel ClCe regulates ATP availability for light-harvesting complex II protein phosphorylation. FRONTIERS IN PLANT SCIENCE 2022; 13:1050355. [PMID: 36483957 PMCID: PMC9722747 DOI: 10.3389/fpls.2022.1050355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 10/31/2022] [Indexed: 06/17/2023]
Abstract
Coping with changes in light intensity is challenging for plants, but well-designed mechanisms allow them to acclimate to most unpredicted situations. The thylakoid K+/H+ antiporter KEA3 and the voltage-dependent Cl- channel VCCN1 play important roles in light acclimation by fine-tuning electron transport and photoprotection. Good evidence exists that the thylakoid Cl- channel ClCe is involved in the regulation of photosynthesis and state transitions in conditions of low light. However, a detailed mechanistic understanding of this effect is lacking. Here we report that the ClCe loss-of-function in Arabidopsis thaliana results in lower levels of phosphorylated light-harvesting complex II (LHCII) proteins as well as lower levels of the photosystem I-LHCII complexes relative to wild type (WT) in low light conditions. The phosphorylation of the photosystem II core D1/D2 proteins was less affected either in low or high light conditions. In low light conditions, the steady-state levels of ATP synthase conductivity and of the total proton flux available for ATP synthesis were lower in ClCe loss-of-function mutants, but comparable to WT at standard and high light intensity. As a long-term acclimation strategy, expression of the ClCe gene was upregulated in WT plants grown in light-limiting conditions, but not in WT plants grown in standard light even when exposed for up to 8 h to low light. Taken together, these results suggest a role of ClCe in the regulation of the ATP synthase activity which under low light conditions impacts LHCII protein phosphorylation and state transitions.
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Affiliation(s)
- Emilija Dukic
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Peter J. Gollan
- Molecular Plant Biology Unit, Department of Life Technologies, University of Turku, Turku, Finland
| | - Steffen Grebe
- Molecular Plant Biology Unit, Department of Life Technologies, University of Turku, Turku, Finland
| | - Virpi Paakkarinen
- Molecular Plant Biology Unit, Department of Life Technologies, University of Turku, Turku, Finland
| | - Andrei Herdean
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Eva-Mari Aro
- Molecular Plant Biology Unit, Department of Life Technologies, University of Turku, Turku, Finland
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
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21
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Lazár D, Niu Y, Nedbal L. Insights on the regulation of photosynthesis in pea leaves exposed to oscillating light. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:6380-6393. [PMID: 36036782 PMCID: PMC9578350 DOI: 10.1093/jxb/erac283] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 08/26/2022] [Indexed: 06/15/2023]
Abstract
Plants growing in nature often experience fluctuating irradiance. However, in the laboratory, the dynamics of photosynthesis are usually explored by instantaneously exposing dark-adapted plants to constant light and examining the dark-to-light transition, which is a poor approximation of natural phenomena. With the aim creating a better approximation, we exposed leaves of pea (Pisum sativum) to oscillating light and measured changes in the functioning of PSI and PSII, and of the proton motive force at the thylakoid membrane. We found that the dynamics depended on the oscillation period, revealing information about the underlying regulatory networks. As demonstrated for a selected oscillation period of 60 s, the regulation tries to keep the reaction centers of PSI and PSII open. We present an evaluation of the data obtained, and discuss the involvement of particular processes in the regulation of photosynthesis. The forced oscillations provided an information-rich fingerprint of complex regulatory networks. We expect future progress in understanding these networks from experiments involving chemical interventions and plant mutants, and by using mathematical modeling and systems identification and control tools.
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Affiliation(s)
- Dušan Lazár
- Department of Biophysics, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Yuxi Niu
- Institute of Bio- and Geosciences/Plant Sciences (IBG-2), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, D-52428 Jülich, Germany
| | - Ladislav Nedbal
- Department of Biophysics, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
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22
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Lyu H, Lazár D. Analyzing the effect of ion binding to the membrane-surface on regulating the light-induced transthylakoid electric potential (ΔΨ m). FRONTIERS IN PLANT SCIENCE 2022; 13:945675. [PMID: 35968094 PMCID: PMC9366520 DOI: 10.3389/fpls.2022.945675] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 06/28/2022] [Indexed: 06/15/2023]
Abstract
The transthylakoid membrane potential (ΔΨm) is essential because it can drive the ATP synthesis through the CF0-CF1 type of ATP-synthase in chloroplasts as an energetic equivalent similar to ΔpH. In addition, a high fraction of proton motive force (PMF) stored as the ΔΨm component is physiologically important in the acclimation of photosynthesis to environmental stresses. It has been shown that ΔΨm is the sum of the Donnan potential difference (ΔΨdn) and the diffusion potential difference (ΔΨd). Specifically, ΔΨdn, ΔΨd, and ΔΨm are strongly associated with the ionic activities near the membrane surface, particularly, the extent of ion binding to the charged/neutral sites adjacent to the membrane surface. However, an in-depth analysis of the effect of altered cationic binding to the membrane surface on adjusting the transthylakoid electric potentials (ΔΨdn, ΔΨd, and ΔΨm) is still missing. This lack of a mechanistic understanding is due to the experimental difficulty of closely observing cations binding to the membrane surface in vivo. In this work, a computer model was proposed to investigate the transthylakoid electric phenomena in the chloroplast focusing on the interaction between cations and the negative charges close to the membrane surface. By employing the model, we simulated the membrane potential and consequently, the measured ECS traces, proxing the ΔΨm, were well described by the computing results on continuous illumination followed by a dark-adapted period. Moreover, the computing data clarified the components of transthylakoid membrane potential, unraveled the functional consequences of altered cationic attachment to the membrane surface on adjusting the transthylakoid electric potential, and further revealed the key role played by Donnan potential in regulating the energization of the thylakoid membrane. The current model for calculating electric potentials can function as a preliminary network for the further development into a more detailed theoretical model by which multiple important variables involved in photosynthesis can be explored.
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Affiliation(s)
- Hui Lyu
- School of Biological Science and Agriculture, Qiannan Normal University for Nationalities, Duyun, China
| | - Dušan Lazár
- Department of Biophysics, Faculty of Science, Palacký University, Olomouc, Czechia
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23
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Mamedov MD, Milanovsky GE, Vitukhnovskaya L, Semenov AY. Measurements of the light-induced steady state electric potential generation by photosynthetic pigment-protein complexes. Biophys Rev 2022; 14:933-939. [DOI: 10.1007/s12551-022-00966-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 05/26/2022] [Indexed: 12/17/2022] Open
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24
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Burlacot A, Dao O, Auroy P, Cuiné S, Li-Beisson Y, Peltier G. Alternative photosynthesis pathways drive the algal CO 2-concentrating mechanism. Nature 2022; 605:366-371. [PMID: 35477755 DOI: 10.1038/s41586-022-04662-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 03/18/2022] [Indexed: 12/13/2022]
Abstract
Global photosynthesis consumes ten times more CO2 than net anthropogenic emissions, and microalgae account for nearly half of this consumption1. The high efficiency of algal photosynthesis relies on a mechanism concentrating CO2 (CCM) at the catalytic site of the carboxylating enzyme RuBisCO, which enhances CO2 fixation2. Although many cellular components involved in the transport and sequestration of inorganic carbon have been identified3,4, how microalgae supply energy to concentrate CO2 against a thermodynamic gradient remains unknown4-6. Here we show that in the green alga Chlamydomonas reinhardtii, the combined action of cyclic electron flow and O2 photoreduction-which depend on PGRL1 and flavodiiron proteins, respectively-generate a low luminal pH that is essential for CCM function. We suggest that luminal protons are used downstream of thylakoid bestrophin-like transporters, probably for the conversion of bicarbonate to CO2. We further establish that an electron flow from chloroplast to mitochondria contributes to energizing non-thylakoid inorganic carbon transporters, probably by supplying ATP. We propose an integrated view of the network supplying energy to the CCM, and describe how algal cells distribute energy from photosynthesis to power different CCM processes. These results suggest a route for the transfer of a functional algal CCM to plants to improve crop productivity.
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Affiliation(s)
- Adrien Burlacot
- Aix Marseille Univ, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache, Saint-Paul-lez-Durance, France.,Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Ousmane Dao
- Aix Marseille Univ, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache, Saint-Paul-lez-Durance, France
| | - Pascaline Auroy
- Aix Marseille Univ, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache, Saint-Paul-lez-Durance, France
| | - Stephan Cuiné
- Aix Marseille Univ, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache, Saint-Paul-lez-Durance, France
| | - Yonghua Li-Beisson
- Aix Marseille Univ, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache, Saint-Paul-lez-Durance, France
| | - Gilles Peltier
- Aix Marseille Univ, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache, Saint-Paul-lez-Durance, France.
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25
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Seydoux C, Storti M, Giovagnetti V, Matuszyńska A, Guglielmino E, Zhao X, Giustini C, Pan Y, Blommaert L, Angulo J, Ruban AV, Hu H, Bailleul B, Courtois F, Allorent G, Finazzi G. Impaired photoprotection in Phaeodactylum tricornutum KEA3 mutants reveals the proton regulatory circuit of diatoms light acclimation. THE NEW PHYTOLOGIST 2022; 234:578-591. [PMID: 35092009 PMCID: PMC9306478 DOI: 10.1111/nph.18003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 01/16/2022] [Indexed: 06/14/2023]
Abstract
Diatoms are successful phytoplankton clades able to acclimate to changing environmental conditions, including e.g. variable light intensity. Diatoms are outstanding at dissipating light energy exceeding the maximum photosynthetic electron transfer (PET) capacity via the nonphotochemical quenching (NPQ) process. While the molecular effectors of NPQ as well as the involvement of the proton motive force (PMF) in its regulation are known, the regulators of the PET/PMF relationship remain unidentified in diatoms. We generated mutants of the H+ /K+ antiporter KEA3 in the model diatom Phaeodactylum tricornutum. Loss of KEA3 activity affects the PET/PMF coupling and NPQ responses at the onset of illumination, during transients and in steady-state conditions. Thus, this antiporter is a main regulator of the PET/PMF coupling. Consistent with this conclusion, a parsimonious model including only two free components, KEA3 and the diadinoxanthin de-epoxidase, describes most of the feedback loops between PET and NPQ. This simple regulatory system allows for efficient responses to fast (minutes) or slow (e.g. diel) changes in light environment, thanks to the presence of a regulatory calcium ion (Ca2+ )-binding domain in KEA3 modulating its activity. This circuit is likely tuned by the NPQ-effector proteins, LHCXs, providing diatoms with the required flexibility to thrive in different ocean provinces.
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Affiliation(s)
- Claire Seydoux
- CNRSCEAINRAEIRIGLPCVUniversité Grenoble AlpesGrenoble38000France
| | - Mattia Storti
- CNRSCEAINRAEIRIGLPCVUniversité Grenoble AlpesGrenoble38000France
| | - Vasco Giovagnetti
- Departement of BiochemistryQueen Mary University of LondonMile End RoadLondonE14NSUK
| | - Anna Matuszyńska
- Computational Life ScienceDepartment of BiologyRWTH Aachen UniversityWorringer Weg 1Aachen52074Germany
| | | | - Xue Zhao
- CNRSCEAINRAEIRIGLPCVUniversité Grenoble AlpesGrenoble38000France
| | - Cécile Giustini
- CNRSCEAINRAEIRIGLPCVUniversité Grenoble AlpesGrenoble38000France
| | - Yufang Pan
- Key Laboratory of Algal BiologyInstitute of HydrobiologyChinese Academy of SciencesWuhan430072China
| | - Lander Blommaert
- Laboratory of Chloroplast Biology and Light Sensing in MicroalgaeInstitut de Biologie Physico ChimiqueCNRSSorbonne UniversitéParis75005France
| | - Jhoanell Angulo
- CNRSCEAINRAEIRIGLPCVUniversité Grenoble AlpesGrenoble38000France
| | - Alexander V. Ruban
- Departement of BiochemistryQueen Mary University of LondonMile End RoadLondonE14NSUK
| | - Hanhua Hu
- Key Laboratory of Algal BiologyInstitute of HydrobiologyChinese Academy of SciencesWuhan430072China
| | - Benjamin Bailleul
- Laboratory of Chloroplast Biology and Light Sensing in MicroalgaeInstitut de Biologie Physico ChimiqueCNRSSorbonne UniversitéParis75005France
| | | | | | - Giovanni Finazzi
- CNRSCEAINRAEIRIGLPCVUniversité Grenoble AlpesGrenoble38000France
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26
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Zuo G, Aiken RM, Feng N, Zheng D, Zhao H, Avenson TJ, Lin X. Fresh perspectives on an established technique: Pulsed amplitude modulation chlorophyll a fluorescence. PLANT-ENVIRONMENT INTERACTIONS (HOBOKEN, N.J.) 2022; 3:41-59. [PMID: 37284008 PMCID: PMC10168060 DOI: 10.1002/pei3.10073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 02/22/2022] [Accepted: 02/25/2022] [Indexed: 06/08/2023]
Abstract
Pulsed amplitude modulation (PAM) chlorophyll a fluorescence provides information about photosynthetic energy transduction. When reliably measured, chlorophyll a fluorescence provides detailed information about critical in vivo photosynthetic processes. Such information has recently provided novel and critical insights into how the yield potential of crops can be improved and it is being used to understand remotely sensed fluorescence, which is termed solar-induced fluorescence and will be solely measured by a satellite scheduled to be launched this year. While PAM chlorophyll a fluorometers measure fluorescence intensity per se, herein we articulate the axiomatic criteria by which instrumentally detected intensities can be assumed to assess fluorescence yield, a phenomenon quite different than fluorescence intensity and one that provides critical insight about how solar energy is variably partitioned into the biosphere. An integrated mathematical, phenomenological, and practical discussion of many useful chlorophyll a fluorescence parameters is presented. We draw attention to, and provide examples of, potential uncertainties that can result from incorrect methodological practices and potentially problematic instrumental design features. Fundamentals of fluorescence measurements are discussed, including the major assumptions underlying the signals and the methodological caveats about taking measurements during both dark- and light-adapted conditions. Key fluorescence parameters are discussed in the context of recent applications under environmental stress. Nuanced information that can be gleaned from intra-comparisons of fluorescence-derived parameters and intercomparisons of fluorescence-derived parameters with those based on other techniques is elucidated.
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Affiliation(s)
- Guanqiang Zuo
- Department of AgronomyKansas State UniversityManhattanKansasUSA
| | - Robert M. Aiken
- Department of AgronomyKansas State UniversityManhattanKansasUSA
- Northwest Research‐Extension CenterKansas State UniversityColbyKansasUSA
| | - Naijie Feng
- College of Coastal Agricultural ScienceGuangdong Ocean UniversityZhanjiangChina
- Shenzhen Research Institute of Guangdong Ocean UniversityShenzhenChina
| | - Dianfeng Zheng
- College of Coastal Agricultural ScienceGuangdong Ocean UniversityZhanjiangChina
- Shenzhen Research Institute of Guangdong Ocean UniversityShenzhenChina
| | - Haidong Zhao
- Department of AgronomyKansas State UniversityManhattanKansasUSA
| | | | - Xiaomao Lin
- Department of AgronomyKansas State UniversityManhattanKansasUSA
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27
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Oung HMO, Mukhopadhyay R, Svoboda V, Charuvi D, Reich Z, Kirchhoff H. Differential response of the photosynthetic machinery to dehydration in older and younger resurrection plants. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:1566-1580. [PMID: 34747457 DOI: 10.1093/jxb/erab485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 11/03/2021] [Indexed: 06/13/2023]
Abstract
A group of vascular plants called homoiochlorophyllous resurrection plants evolved unique capabilities to protect their photosynthetic machinery against desiccation-induced damage. This study examined whether the ontogenetic status of the resurrection plant Craterostigma pumilum has an impact on how the plant responds to dehydration at the thylakoid membrane level to prepare cells for the desiccated state. Thus, younger plants (<4 months) were compared with their older (>6 months) counterparts. Ultrastructural analysis provided evidence that younger plants suppressed senescence-like programs that are realized in older plants. During dehydration, older plants degrade specific subunits of the photosynthetic apparatus such as the D1 subunit of PSII and subunits of the cytochrome b6f complex. The latter leads to a controlled down-regulation of linear electron transport. In contrast, younger plants increased photoprotective high-energy quenching mechanisms and maintained a high capability to replace damaged D1 subunits. It follows that depending on the ontogenetic state, either more degradation-based or more photoprotective mechanisms are employed during dehydration of Craterostigma pumilum.
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Affiliation(s)
- Hui Min Olivia Oung
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Roma Mukhopadhyay
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Vaclav Svoboda
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Dana Charuvi
- Institute of Plant Sciences, Agricultural Research Organization - Volcani Institute, Rishon LeZion 7505101, Israel
| | - Ziv Reich
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
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28
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Uflewski M, Mielke S, Correa Galvis V, von Bismarck T, Chen X, Tietz E, Ruß J, Luzarowski M, Sokolowska E, Skirycz A, Eirich J, Finkemeier I, Schöttler MA, Armbruster U. Functional characterization of proton antiport regulation in the thylakoid membrane. PLANT PHYSIOLOGY 2021; 187:2209-2229. [PMID: 33742682 PMCID: PMC8644300 DOI: 10.1093/plphys/kiab135] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 03/03/2021] [Indexed: 05/21/2023]
Abstract
During photosynthesis, energy is transiently stored as an electrochemical proton gradient across the thylakoid membrane. The resulting proton motive force (pmf) is composed of a membrane potential (ΔΨ) and a proton concentration gradient (ΔpH) and powers the synthesis of ATP. Light energy availability for photosynthesis can change very rapidly and frequently in nature. Thylakoid ion transport proteins buffer the effects that light fluctuations have on photosynthesis by adjusting pmf and its composition. Ion channel activities dissipate ΔΨ, thereby reducing charge recombinations within photosystem II. The dissipation of ΔΨ allows for increased accumulation of protons in the thylakoid lumen, generating the signal that activates feedback downregulation of photosynthesis. Proton export from the lumen via the thylakoid K+ exchange antiporter 3 (KEA3), instead, decreases the ΔpH fraction of the pmf and thereby reduces the regulatory feedback signal. Here, we reveal that the Arabidopsis (Arabidopsis thaliana) KEA3 protein homo-dimerizes via its C-terminal domain. This C-terminus has a regulatory function, which responds to light intensity transients. Plants carrying a C-terminus-less KEA3 variant show reduced feed-back downregulation of photosynthesis and suffer from increased photosystem damage under long-term high light stress. However, during photosynthetic induction in high light, KEA3 deregulation leads to an increase in carbon fixation rates. Together, the data reveal a trade-off between long-term photoprotection and a short-term boost in carbon fixation rates, which is under the control of the KEA3 C-terminus.
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Affiliation(s)
- Michał Uflewski
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | - Sarah Mielke
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | | | | | - Xiaoheng Chen
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | - Enrico Tietz
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | - Jeremy Ruß
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | - Marcin Luzarowski
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | - Ewelina Sokolowska
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | - Aleksandra Skirycz
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
- Boyce Thompson Institute, Ithaca 14853, New York
| | - Jürgen Eirich
- Plant Physiology, Institute of Plant Biology and Biotechnology, University of Münster, Münster 48149, Germany
| | - Iris Finkemeier
- Plant Physiology, Institute of Plant Biology and Biotechnology, University of Münster, Münster 48149, Germany
| | | | - Ute Armbruster
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
- Author for communication:
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29
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Trinh MDL, Hashimoto A, Kono M, Takaichi S, Nakahira Y, Masuda S. Lack of plastid-encoded Ycf10, a homolog of the nuclear-encoded DLDG1 and the cyanobacterial PxcA, enhances the induction of non-photochemical quenching in tobacco. PLANT DIRECT 2021; 5:e368. [PMID: 34938941 PMCID: PMC8671777 DOI: 10.1002/pld3.368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 05/05/2023]
Abstract
pH homeostasis in the chloroplast is crucial for the control of photosynthesis and other metabolic processes in plants. Recently, nuclear-encoded Day-Length-dependent Delayed Greening1 (DLDG1) and Fluctuating-Light Acclimation Protein1 (FLAP1) that are required for the light-inducible optimization of plastidial pH in Arabidopsis thaliana were identified. DLDG1 and FLAP1 homologs are specifically conserved in oxygenic phototrophs, and a DLDG1 homolog, Ycf10, is encoded in the chloroplast genome in plant cells. However, the function of Ycf10 and its physiological significance are unknown. To address this, we constructed ycf10 tobacco Nicotiana tabacum mutants and characterized their phenotypes. The ycf10 tobacco mutants grown under continuous-light conditions showed a pale-green phenotype only in developing leaves, and it was suppressed in short-day conditions. The ycf10 mutants also induced excessive non-photochemical quenching (NPQ) compared with those in the wild-type at the induction stage of photosynthesis. These phenotypes resemble those of Arabidopsis dldg1 mutants, suggesting that they have similar functions. However, there are distinct differences between the two mutant phenotypes: The highly induced NPQ in tobacco ycf10 and the Arabidopsis dldg1 mutants are diminished and enhanced, respectively, with increasing duration of the fluctuating actinic-light illumination. Ycf10 and DLDG1 were previously shown to localize in chloroplast envelope-membranes, suggesting that Ycf10 and DLDG1 differentially control H+ exchange across these membranes in a light-dependent manner to control photosynthesis.
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Affiliation(s)
- Mai Duy Luu Trinh
- Department of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Akira Hashimoto
- Department of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Masaru Kono
- Department of Biological Science, Graduate School of ScienceThe University of TokyoTokyoJapan
| | - Shinichi Takaichi
- Department of Molecular MicrobiologyTokyo University of AgricultureTokyoJapan
| | | | - Shinji Masuda
- Department of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
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30
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Kanazawa A, Chattopadhyay A, Kuhlgert S, Tuitupou H, Maiti T, Kramer DM. Light potentials of photosynthetic energy storage in the field: what limits the ability to use or dissipate rapidly increased light energy? ROYAL SOCIETY OPEN SCIENCE 2021; 8:211102. [PMID: 34925868 PMCID: PMC8672073 DOI: 10.1098/rsos.211102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 11/08/2021] [Indexed: 06/14/2023]
Abstract
The responses of plant photosynthesis to rapid fluctuations in environmental conditions are critical for efficient conversion of light energy. These responses are not well-seen laboratory conditions and are difficult to probe in field environments. We demonstrate an open science approach to this problem that combines multifaceted measurements of photosynthesis and environmental conditions, and an unsupervised statistical clustering approach. In a selected set of data on mint (Mentha sp.), we show that 'light potentials' for linear electron flow and non-photochemical quenching (NPQ) upon rapid light increases are strongly suppressed in leaves previously exposed to low ambient photosynthetically active radiation (PAR) or low leaf temperatures, factors that can act both independently and cooperatively. Further analyses allowed us to test specific mechanisms. With decreasing leaf temperature or PAR, limitations to photosynthesis during high light fluctuations shifted from rapidly induced NPQ to photosynthetic control of electron flow at the cytochrome b6f complex. At low temperatures, high light induced lumen acidification, but did not induce NPQ, leading to accumulation of reduced electron transfer intermediates, probably inducing photodamage, revealing a potential target for improving the efficiency and robustness of photosynthesis. We discuss the implications of the approach for open science efforts to understand and improve crop productivity.
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Affiliation(s)
- Atsuko Kanazawa
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Abhijnan Chattopadhyay
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI 48824, USA
- Department of Statistics and Probability, Michigan State University, East Lansing, MI 48824, USA
| | - Sebastian Kuhlgert
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI 48824, USA
| | - Hainite Tuitupou
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI 48824, USA
| | - Tapabrata Maiti
- Department of Statistics and Probability, Michigan State University, East Lansing, MI 48824, USA
| | - David M. Kramer
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI 48824, USA
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
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31
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Chovancek E, Zivcak M, Brestic M, Hussain S, Allakhverdiev SI. The different patterns of post-heat stress responses in wheat genotypes: the role of the transthylakoid proton gradient in efficient recovery of leaf photosynthetic capacity. PHOTOSYNTHESIS RESEARCH 2021; 150:179-193. [PMID: 33393064 DOI: 10.1007/s11120-020-00812-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 12/08/2020] [Indexed: 05/28/2023]
Abstract
The frequency and severity of heat waves are expected to increase in the near future, with a significant impact on physiological functions and yield of crop plants. In this study, we assessed the residual post-heat stress effects on photosynthetic responses of six diverse winter wheat (Triticum sp.) genotypes, differing in country of origin, taxonomy and ploidy (tetraploids vs. hexaploids). After 5 days of elevated temperatures (up to 38 °C), the photosynthetic parameters recorded on the first day of recovery (R1) as well as after the next 4-5 days of the recovery (R2) were compared to those of the control plants (C) grown under moderate temperatures. Based on the values of CO2 assimilation rate (A) and the maximum rates of carboxylation (VCmax) in R1, we identified that the hexaploid (HEX) and tetraploid (TET) species clearly differed in the strength of their response to heat stress. Next, the analyses of gas exchange, simultaneous measurements of PSI and PSII photochemistry and the measurements of electrochromic bandshift (ECS) have consistently shown that photosynthetic and photoprotective functions in leaves of TET genotypes were almost fully recovered in R2, whereas the recovery of photosynthetic and photoprotective functions in the HEX group in R2 was still rather low. A poor recovery was associated with an overly reduced acceptor side of photosystem I as well as high values of the electric membrane potential (Δψ component of the proton motive force, pmf) in the chloroplast. On the other hand, a good recovery of photosynthetic capacity and photoprotective functions was clearly associated with an enhanced ΔpH component of the pmf, thus demonstrating a key role of efficient regulation of proton transport to ensure buildup of the transthylakoid proton gradient needed for photosynthesis restoration after high-temperature episodes.
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Affiliation(s)
- Erik Chovancek
- Department of Plant Physiology, Slovak University of Agriculture, Nitra, Slovak Republic
| | - Marek Zivcak
- Department of Plant Physiology, Slovak University of Agriculture, Nitra, Slovak Republic.
| | - Marian Brestic
- Department of Plant Physiology, Slovak University of Agriculture, Nitra, Slovak Republic
| | - Sajad Hussain
- College of Agronomy, Sichuan Agricultural University, Chengdu, People's Republic of China
- Sichuan Engineering Research Center for Crop Strip Intercropping System, Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Sichuan Agricultural University, Chengdu, People's Republic of China
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32
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Mellon M, Storti M, Vera-Vives AM, Kramer DM, Alboresi A, Morosinotto T. Inactivation of mitochondrial complex I stimulates chloroplast ATPase in Physcomitrium patens. PLANT PHYSIOLOGY 2021; 187:931-946. [PMID: 34608952 PMCID: PMC8491079 DOI: 10.1093/plphys/kiab276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 05/18/2021] [Indexed: 06/11/2023]
Abstract
Light is the ultimate source of energy for photosynthetic organisms, but respiration is fundamental for supporting metabolism during the night or in heterotrophic tissues. In this work, we isolated Physcomitrella (Physcomitrium patens) plants with altered respiration by inactivating Complex I (CI) of the mitochondrial electron transport chain by independently targeting on two essential subunits. Inactivation of CI caused a strong growth impairment even in fully autotrophic conditions in tissues where all cells are photosynthetically active, demonstrating that respiration is essential for photosynthesis. CI mutants showed alterations in the stoichiometry of respiratory complexes while the composition of photosynthetic apparatus was substantially unaffected. CI mutants showed altered photosynthesis with high activity of both Photosystems I and II, likely the result of high chloroplast ATPase activity that led to smaller ΔpH formation across thylakoid membranes, decreasing photosynthetic control on cytochrome b6f in CI mutants. These results demonstrate that alteration of respiratory activity directly impacts photosynthesis in P. patens and that metabolic interaction between organelles is essential in their ability to use light energy for growth.
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Affiliation(s)
- Marco Mellon
- Department of Biology, University of Padova, 35121 Padova, Italy
| | - Mattia Storti
- Department of Biology, University of Padova, 35121 Padova, Italy
| | | | - David M. Kramer
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
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33
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Mathiot C, Alric J. Standard units for ElectroChromic Shift measurements in plant biology. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:6467-6473. [PMID: 34089606 DOI: 10.1093/jxb/erab261] [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: 01/27/2021] [Accepted: 06/04/2021] [Indexed: 06/12/2023]
Abstract
The absorbance shift of pigments is proportional to the membrane potential (Δψ) in plants, green algae, and many photosynthetic bacteria. It is currently denoted as ElectroChromic Shift (ECS) at 515-520 nm for plant carotenoids. It is increasingly being used for phenotyping plants for traits related to photosynthesis or chloroplast metabolism because it is a non-invasive technique and also because more instruments are now commercially available from various manufacturers. The ECS technique is currently used to monitor the post-illumination decay of the proton-motive force (pmf), but it has a more general use for quantitative studies on photosynthetic energy transduction. Here we briefly summarize the basic knowledge on ECS, emphasize the full potential of this technique, and propose a quantitative analysis of the photosynthetic performance with the definition of a transmission coefficient for electrons along the photosynthetic chain.
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Affiliation(s)
- Charlie Mathiot
- Aix Marseille Univ, CEA, CNRS, BIAM, UMR 7265, Photosynthesis and Environment, F-13108 Saint Paul-Lez-Durance, France
- Groupe Biomasse 3G, CEA Tech, CEA Cadarache, F-13108 Saint-Paul-Lez-Durance, France
| | - Jean Alric
- Aix Marseille Univ, CEA, CNRS, BIAM, UMR 7265, Photosynthesis and Environment, F-13108 Saint Paul-Lez-Durance, France
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Wilson S, Johnson MP, Ruban AV. Proton motive force in plant photosynthesis dominated by ΔpH in both low and high light. PLANT PHYSIOLOGY 2021; 187:263-275. [PMID: 34618143 PMCID: PMC8418402 DOI: 10.1093/plphys/kiab270] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 05/23/2021] [Indexed: 05/08/2023]
Abstract
The proton motive force (pmf) across the thylakoid membrane couples photosynthetic electron transport and ATP synthesis. In recent years, the electrochromic carotenoid and chlorophyll absorption band shift (ECS), peaking ∼515 nm, has become a widely used probe to measure pmf in leaves. However, the use of this technique to calculate the parsing of the pmf between the proton gradient (ΔpH) and electric potential (Δψ) components remains controversial. Interpretation of the ECS signal is complicated by overlapping absorption changes associated with violaxanthin de-epoxidation to zeaxanthin (ΔA505) and energy-dependent nonphotochemical quenching (qE; ΔA535). In this study, we used Arabidopsis (Arabidopsis thaliana) plants with altered xanthophyll cycle activity and photosystem II subunit S (PsbS) content to disentangle these overlapping contributions. In plants where overlap among ΔA505, ΔA535, and ECS is diminished, such as npq4 (lacking ΔA535) and npq1npq4 (also lacking ΔA505), the parsing method implies the Δψ contribution is virtually absent and pmf is solely composed of ΔpH. Conversely, in plants where ΔA535 and ECS overlap is enhanced, such as L17 (a PsbS overexpressor) and npq1 (where ΔA535 is blue-shifted to 525 nm) the parsing method implies a dominant contribution of Δψ to the total pmf. These results demonstrate the vast majority of the pmf attributed by the ECS parsing method to Δψ is caused by ΔA505 and ΔA535 overlap, confirming pmf is dominated by ΔpH following the first 60 s of continuous illumination under both low and high light conditions. Further implications of these findings for the regulation of photosynthesis are discussed.
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Affiliation(s)
- Sam Wilson
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Matthew P. Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, UK
| | - Alexander V. Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
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Shukshina AK, Terentyev VV. Involvement of Carbonic Anhydrase CAH3 in the Structural and Functional Stabilization of the Water-Oxidizing Complex of Photosystem II from Chlamydomonas reinhardtii. BIOCHEMISTRY (MOSCOW) 2021; 86:867-877. [PMID: 34284710 DOI: 10.1134/s0006297921070075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The involvement of carbonic anhydrases (CA) and CA activity in the functioning of photosystem II (PSII) has been studied for a long time and has been shown in many works. However, so far only for CAH3 from Chlamydomonas reinhardtii there is evidence for its association with the donor side of PSII, where the CA activity of CAH3 can influence the functioning of the water-oxidizing complex (WOC). Our results suggest that CAH3 is also involved in the organization of the native structure of WOC independently of its CA activity. It was shown that in PSII preparations from wild type (WT) the high O2-evolving activity of WOC was observed up to 100 mM NaCl in the medium and practically did not decrease with increasing incubation time with NaCl. At the same time, the WOC function in PSII preparations from CAH3-deficient mutant cia3 is significantly inhibited already at NaCl concentrations above 35 mM, reaching 50% at 100 mM NaCl and increased incubation time. It is suggested that the absence of CAH3 in PSII from cia3 causes disruption of the native structure of WOC, allowing more pronounced conformational changes of its proteins and, consequently, suppression of the WOC active center function, when the ionic strength of the medium is increased. The results of Western blot analysis indicate a more difficult removal of PsbP protein from PSII of cia3 at higher NaCl concentrations, apparently due to the changes in the intermolecular interactions between proteins of WOC in the absence of CAH3. At the same time, the values of the maximum quantum yield of PSII did not practically differ between preparations from WT and cia3, indicating no effect of CAH3 on the photoinduced electron transfer in the reaction center of PSII. The obtained results indicate the involvement of the CAH3 protein in the native organization of the WOC and, as a consequence, in the stabilization of its functional state in PSII from C. reinhardtii.
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Affiliation(s)
- Anna K Shukshina
- Institute of Basic Biological Problems, Pushchino Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Vasily V Terentyev
- Institute of Basic Biological Problems, Pushchino Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
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Li M, Svoboda V, Davis G, Kramer D, Kunz HH, Kirchhoff H. Impact of ion fluxes across thylakoid membranes on photosynthetic electron transport and photoprotection. NATURE PLANTS 2021; 7:979-988. [PMID: 34140667 DOI: 10.1038/s41477-021-00947-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 05/18/2021] [Indexed: 05/06/2023]
Abstract
In photosynthetic thylakoid membranes the proton motive force (pmf) not only drives ATP synthesis, in addition it is central to controlling and regulating energy conversion. As a consequence, dynamic fine-tuning of the two pmf components, electrical (Δψ) and chemical (ΔpH), is an essential element for adjusting photosynthetic light reactions to changing environmental conditions. Good evidence exists that the Δψ/ΔpH partitioning is controlled by thylakoid potassium and chloride ion transporters and channels. However, a detailed mechanistic understanding of how these thylakoid ion transporter/channels control pmf partitioning is lacking. Here, we combined functional measurements on potassium and chloride ion transporter and channel loss-of-function mutants with extended mathematical simulations of photosynthetic light reactions in thylakoid membranes to obtain detailed kinetic insights into the complex interrelationship between membrane energization and ion fluxes across thylakoid membranes. The data reveal that potassium and chloride fluxes in the thylakoid lumen determined by the K+/H+ antiporter KEA3 and the voltage-gated Cl- channel VCCN1/Best1 have distinct kinetic responses that lead to characteristic and light-intensity-dependent Δψ/ΔpH oscillations. These oscillations fine-tune photoprotective mechanisms and electron transport which are particularly important during the first minutes of illumination and under fluctuating light conditions. By employing the predictive power of the model, we unravelled the functional consequences of changes in KEA3 and VCCN1 abundance and regulatory/enzymatic parameters on membrane energization and photoprotection.
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Affiliation(s)
- Meng Li
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
- School of Oceanography, University of Washington, Seattle, WA, USA
| | - Vaclav Svoboda
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Geoffry Davis
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
| | - David Kramer
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
- Department of Biochemistry, Michigan State University, East Lansing, MI, USA
| | - Hans-Henning Kunz
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA.
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Cruz JA, Avenson TJ. Photosynthesis: a multiscopic view. JOURNAL OF PLANT RESEARCH 2021; 134:665-682. [PMID: 34170422 DOI: 10.1007/s10265-021-01321-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 06/11/2021] [Indexed: 06/13/2023]
Abstract
A recurring analogy for photosynthesis research is the fable of the blind men and the elephant. Photosynthesis has many complex working parts, which has driven the need to study each of them individually, with an inherent understanding that a more complete picture will require systematic integration of these views. However, unlike the blind men, who are limited to using their hands, researchers have developed over the past decades a repertoire of methods for studying these components, many of which capitalize on unique features intrinsic to each. More recent concerns about food security and clean, renewable energy have increased support for applied photosynthesis research, with the idea of either improving photosynthetic performance as a desired trait in select species or using photosynthetic measurements as a phenotyping tool in breeding efforts or for high precision crop management. In this review, we spotlight the migration of approaches for studying photosynthesis from the laboratory into field environments, highlight some recent advances and speculate on areas where further development would be fruitful, with an eye towards how applied photosynthesis research can have impacts at local and global scales.
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Affiliation(s)
- Jeffrey A Cruz
- Plant Research Laboratories, Michigan State University, 612 Wilson Road, MI, S-206, Lansing, USA.
- Department of Biochemistry and Molecular Biology, Michigan State University, Lansing, MI, USA.
| | - Thomas J Avenson
- Department of Plant Sciences, University of Cambridge, CB2 9EW, Cambridge, UK
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Cheong KY, Firlar E, Ficaro L, Gorbunov MY, Kaelber JT, Falkowski PG. Saturation of thylakoid-associated fatty acids facilitates bioenergetic coupling in a marine diatom allowing for thermal acclimation. GLOBAL CHANGE BIOLOGY 2021; 27:3133-3144. [PMID: 33749034 DOI: 10.1111/gcb.15612] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 03/03/2021] [Indexed: 06/12/2023]
Abstract
In a rapidly warming world, we ask, "What limits the potential of marine diatoms to acclimate to elevated temperatures?," a group of ecologically successful unicellular eukaryotic photoautotrophs that evolved in a cooler ocean and are critical to marine food webs. To this end, we examined thermal tolerance mechanisms related to photosynthesis in the sequenced and transformable model diatom Phaeodactylum tricornutum. Data from transmission electron microscopy (TEM) and fatty acid methyl ester-gas chromatography mass spectrometry (FAME-GCMS) suggest that saturating thylakoid-associated fatty acids allowed rapid (on the order of hours) thermal tolerance up to 28.5°C. Beyond this critical temperature, thylakoid ultrastructure became severely perturbed. Biophysical analyses revealed that electrochemical leakage through the thylakoid membranes was extremely sensitive to elevated temperature (Q10 of 3.5). Data suggest that the loss of the proton motive force (pmf) occurred even when heat-labile photosystem II (PSII) was functioning, and saturation of thylakoid-associated fatty acids was active. Indeed, growth was inhibited when leakage of pmf through thylakoid membranes was insufficiently compensated by proton input from PSII. Our findings provide a mechanistic understanding of the importance of rapid saturation of thylakoid-associated fatty acids for ultrastructure maintenance and a generation of pmf at elevated temperatures. To the extent these experimental results apply, the ability of diatoms to generate a pmf may be a sensitive parameter for thermal sensitivity diagnosis in phytoplankton.
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Affiliation(s)
- Kuan Yu Cheong
- Environmental Biophysics and Molecular Ecology Program, Department of Marine and Coastal Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA
- Department of Plant Biology, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA
| | - Emre Firlar
- Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
- Rutgers New Jersey Cryo-Electron Microscopy & Tomography Core Facility, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Lia Ficaro
- Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
- Rutgers New Jersey Cryo-Electron Microscopy & Tomography Core Facility, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Maxim Y Gorbunov
- Environmental Biophysics and Molecular Ecology Program, Department of Marine and Coastal Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA
| | - Jason T Kaelber
- Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
- Rutgers New Jersey Cryo-Electron Microscopy & Tomography Core Facility, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Paul G Falkowski
- Environmental Biophysics and Molecular Ecology Program, Department of Marine and Coastal Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA
- Department of Earth and Planetary Sciences, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
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PGRL2 triggers degradation of PGR5 in the absence of PGRL1. Nat Commun 2021; 12:3941. [PMID: 34168134 PMCID: PMC8225790 DOI: 10.1038/s41467-021-24107-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Accepted: 06/01/2021] [Indexed: 12/01/2022] Open
Abstract
In plants, inactivation of either of the thylakoid proteins PGR5 and PGRL1 impairs cyclic electron flow (CEF) around photosystem I. Because PGR5 is unstable in the absence of the redox-active PGRL1, but not vice versa, PGRL1 is thought to be essential for CEF. However, we show here that inactivation of PGRL2, a distant homolog of PGRL1, relieves the need for PGRL1 itself. Conversely, high levels of PGRL2 destabilize PGR5 even when PGRL1 is present. In the absence of both PGRL1 and PGRL2, PGR5 alters thylakoid electron flow and impairs plant growth. Consequently, PGR5 can operate in CEF on its own, and is the target of the CEF inhibitor antimycin A, but its activity must be modulated by PGRL1. We conclude that PGRL1 channels PGR5 activity, and that PGRL2 triggers the degradation of PGR5 when the latter cannot productively interact with PGRL1. It is currently thought that the thylakoid proteins PGRL1 and PGR5 form a complex to mediate cyclic electron flow (CEF) around photosystem I. Here the authors show that CEF can in fact be mediated by PGR5 alone and that PGRL1 and the homologous PGRL2 modify the process by modulating PGR5 activity and stability.
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Zhao W, Zhang QS, Tan Y, Liu Z, Ma MY, Wang MX, Luo CY. An underlying mechanism of qE deficiency in marine angiosperm Zostera marina. PHOTOSYNTHESIS RESEARCH 2021; 148:87-99. [PMID: 33934290 DOI: 10.1007/s11120-021-00836-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 04/17/2021] [Indexed: 06/12/2023]
Abstract
Non-photochemical quenching (NPQ) of photosystem II (PSII) fluorescence is one of the most important protective mechanisms enabling the survival of phototropic organisms under high-light conditions. A low-efficiency NPQ, characterized by weak NPQ induction capacity and a low level of protective NPQ, was observed in the marine angiosperm Zostera marina, which inhabits the shallow water regions. Furthermore, chlorophyll fluorescence and Western blot analysis verified that the fast-inducted component of NPQ, i.e., the energy-dependent quenching (qE), was not present in this species. In contrast with the lack of PSII antenna quenching sites for qE induction in brown algae and the lack of functional XC in Ulvophyceae belonging to green algae, all the antenna proteins and the functional XC are present in Z. marina. A novel underlying mechanism was observed that the limited construction of the trans-thylakoid proton gradient (ΔpH) caused by photoinactivation of the oxygen evolving complex (OEC) did not induce protonation of PsbS, thus explaining the inability to form quenching sites for qE induction. Although the ΔpH established under light exposure activated violaxanthin (V) de-epoxidase enzyme to catalyze conversion of V via antheraxanthin (A) and then to zeaxanthin (Z), the quenching capacity of de-epoxidized pigment was weak in Z. marina. We suggest that the low-efficiency NPQ was conducive to efficiently utilize the limited electrons to perform photosynthesis, resisting the adverse effect of OEC photoinactivation on the photosynthetic rate.
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Affiliation(s)
- Wei Zhao
- Ocean School, Yantai University, Yantai, 264005, People's Republic of China
| | - Quan Sheng Zhang
- Ocean School, Yantai University, Yantai, 264005, People's Republic of China.
| | - Ying Tan
- Ocean School, Yantai University, Yantai, 264005, People's Republic of China
| | - Zhe Liu
- Ocean School, Yantai University, Yantai, 264005, People's Republic of China
| | - Ming Yu Ma
- Ocean School, Yantai University, Yantai, 264005, People's Republic of China
| | - Meng Xin Wang
- Ocean School, Yantai University, Yantai, 264005, People's Republic of China
| | - Cheng Ying Luo
- Ocean School, Yantai University, Yantai, 264005, People's Republic of China
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Photosynthetic Linear Electron Flow Drives CO 2 Assimilation in Maize Leaves. Int J Mol Sci 2021; 22:ijms22094894. [PMID: 34063101 PMCID: PMC8124781 DOI: 10.3390/ijms22094894] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 05/02/2021] [Accepted: 05/04/2021] [Indexed: 12/24/2022] Open
Abstract
Photosynthetic organisms commonly develop the strategy to keep the reaction center chlorophyll of photosystem I, P700, oxidized for preventing the generation of reactive oxygen species in excess light conditions. In photosynthesis of C4 plants, CO2 concentration is kept at higher levels around ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) by the cooperation of the mesophyll and bundle sheath cells, which enables them to assimilate CO2 at higher rates to survive under drought stress. However, the regulatory mechanism of photosynthetic electron transport for P700 oxidation is still poorly understood in C4 plants. Here, we assessed gas exchange, chlorophyll fluorescence, electrochromic shift, and near infrared absorbance in intact leaves of maize (a NADP-malic enzyme C4 subtype species) in comparison with mustard, a C3 plant. Instead of the alternative electron sink due to photorespiration in the C3 plant, photosynthetic linear electron flow was strongly suppressed between photosystems I and II, dependent on the difference of proton concentration across the thylakoid membrane (ΔpH) in response to the suppression of CO2 assimilation in maize. Linear relationships among CO2 assimilation rate, linear electron flow, P700 oxidation, ΔpH, and the oxidation rate of ferredoxin suggested that the increase of ΔpH for P700 oxidation was caused by the regulation of proton conductance of chloroplast ATP synthase but not by promoting cyclic electron flow. At the scale of intact leaves, the ratio of PSI to PSII was estimated almost 1:1 in both C3 and C4 plants. Overall, the photosynthetic electron transport was regulated for P700 oxidation in maize through the same strategies as in C3 plants only except for the capacity of photorespiration despite the structural and metabolic differences in photosynthesis between C3 and C4 plants.
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Rotor subunits adaptations in ATP synthases from photosynthetic organisms. Biochem Soc Trans 2021; 49:541-550. [PMID: 33890627 PMCID: PMC8106487 DOI: 10.1042/bst20190936] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/17/2021] [Accepted: 03/22/2021] [Indexed: 11/17/2022]
Abstract
Driven by transmembrane electrochemical ion gradients, F-type ATP synthases are the primary source of the universal energy currency, adenosine triphosphate (ATP), throughout all domains of life. The ATP synthase found in the thylakoid membranes of photosynthetic organisms has some unique features not present in other bacterial or mitochondrial systems. Among these is a larger-than-average transmembrane rotor ring and a redox-regulated switch capable of inhibiting ATP hydrolysis activity in the dark by uniquely adapted rotor subunit modifications. Here, we review recent insights into the structure and mechanism of ATP synthases specifically involved in photosynthesis and explore the cellular physiological consequences of these adaptations at short and long time scales.
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Aranda Sicilia MN, Sánchez Romero ME, Rodríguez Rosales MP, Venema K. Plastidial transporters KEA1 and KEA2 at the inner envelope membrane adjust stromal pH in the dark. THE NEW PHYTOLOGIST 2021; 229:2080-2090. [PMID: 33111995 DOI: 10.1111/nph.17042] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 10/10/2020] [Indexed: 05/08/2023]
Abstract
Photosynthesis and carbon fixation depend critically on the regulation of pH in chloroplast compartments in the daylight and at night. While it is established that an alkaline stroma is required for carbon fixation, it is not known how alkaline stromal pH is formed, maintained or regulated. We tested whether two envelope transporters, AtKEA1 and AtKEA2, directly affected stromal pH in isolated Arabidopsis chloroplasts using the fluorescent probe 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF). External K+ -induced alkalinization of the stroma was observed in chloroplasts from wild-type (WT) plants but not from kea1kea2 mutants, suggesting that KEA1 and KEA2 mediate K+ uptake/H+ loss to modulate stromal pH. While light-stimulated alkalinization of the stroma was independent of KEA1 and KEA2, the rate of decay to neutral pH in the dark is delayed in kea1kea2 mutants. However, the dark-induced loss of a pH gradient across the thylakoid membrane was similar in WT and mutant chloroplasts. This indicates that proton influx from the cytosol mediated by envelope K+ /H+ antiporters contributes to adjustment of stromal pH upon light to dark transitions.
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Affiliation(s)
- María Nieves Aranda Sicilia
- Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, CSIC, C/ Profesor Albareda 1, Granada, 18008, Spain
| | - María Elena Sánchez Romero
- Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, CSIC, C/ Profesor Albareda 1, Granada, 18008, Spain
| | - María Pilar Rodríguez Rosales
- Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, CSIC, C/ Profesor Albareda 1, Granada, 18008, Spain
| | - Kees Venema
- Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, CSIC, C/ Profesor Albareda 1, Granada, 18008, Spain
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Raven JA. Determinants, and implications, of the shape and size of thylakoids and cristae. JOURNAL OF PLANT PHYSIOLOGY 2021; 257:153342. [PMID: 33385618 DOI: 10.1016/j.jplph.2020.153342] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 11/25/2020] [Accepted: 12/08/2020] [Indexed: 06/12/2023]
Abstract
Thylakoids are flattened sacs isolated from other membranes; cristae are attached to the rest of the inner mitochondrial membrane by the crista junction, but the crista lumen is separated from the intermembrane space. The shape of thylakoids and cristae involves membranes with small (5-30 nm) radii of curvature. While the mechanism of curvature is not entirely clear, it seems to be largely a function of Curt proteins in thylakoids and Mitochondrial Organising Site and Crista Organising Centre proteins and oligomeric FOF1 ATP synthase in cristae. A subordinate, or minimal, role is attributable to lipids with areas of their head group area greater (convex leaflet) or smaller (concave leaflet) than the area of the lipid tail; examples of the latter group are monogalactosyldiglyceride in thylakoids and cardiolipin in cristae. The volume per unit area on the lumen side of the membrane is less than that of the chloroplast stroma or cyanobacterial cytosol for thylakoids, and mitochondrial matrix for cristae. A low volume per unit area of thylakoids and cristae means a small lumen width that is the average of wider spaces between lipid parts of the membranes and the narrower gaps dominated by extra-membrane components of transmembrane proteins. These structural constraints have important implications for the movement of the electron carriers plastocyanin and cytochrome c6 (thylakoids) and cytochrome c (cristae) and hence the separation of the membrane-associated electron donors to, and electron acceptors from, these water-soluble electron carriers. The donor/acceptor pairs, are the cytochrome fb6Fenh complex and P700+ in thylakoids, and Complex III and Complex IV of cristae. The other energy flux parallel to the membranes is that of the proton motive force generated by redox-powered H+ pumps into the lumen to the proton motive force use in ATP synthesis by H+ flux from the lumen through the ATP synthase. For both the electron transport and proton motive force movement, concentration differences of reduced and oxidised electron carriers and protonated and deprotonated pH buffers are involved. The need for diffusion along a congested route of these energy transfer agents may limit the separation of sources and sinks parallel to the membranes of thylakoids and cristae.
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Affiliation(s)
- John A Raven
- Division of Plant Science, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK; University of Technology, Sydney, Climate Change Cluster, Faculty of Science, Sydney, Ultimo, NSW, 2007, Australia; School of Biological Sciences, University of Western Australia, Crawley, WA, 6009, Australia.
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Shimakawa G, Hanawa H, Wada S, Hanke GT, Matsuda Y, Miyake C. Physiological Roles of Flavodiiron Proteins and Photorespiration in the Liverwort Marchantia polymorpha. FRONTIERS IN PLANT SCIENCE 2021; 12:668805. [PMID: 34489990 PMCID: PMC8418088 DOI: 10.3389/fpls.2021.668805] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 07/30/2021] [Indexed: 05/19/2023]
Abstract
Against the potential risk in oxygenic photosynthesis, that is, the generation of reactive oxygen species, photosynthetic electron transport needs to be regulated in response to environmental fluctuations. One of the most important regulations is keeping the reaction center chlorophyll (P700) of photosystem I in its oxidized form in excess light conditions. The oxidation of P700 is supported by dissipating excess electrons safely to O2, and we previously found that the molecular mechanism of the alternative electron sink is changed from flavodiiron proteins (FLV) to photorespiration in the evolutionary history from cyanobacteria to plants. However, the overall picture of the regulation of photosynthetic electron transport is still not clear in bryophytes, the evolutionary intermediates. Here, we investigated the physiological roles of FLV and photorespiration for P700 oxidation in the liverwort Marchantia polymorpha by using the mutants deficient in FLV (flv1) at different O2 partial pressures. The effective quantum yield of photosystem II significantly decreased at 2kPa O2 in flv1, indicating that photorespiration functions as the electron sink. Nevertheless, it was clear from the phenotype of flv1 that FLV was dominant for P700 oxidation in M. polymorpha. These data suggested that photorespiration has yet not replaced FLV in functioning for P700 oxidation in the basal land plant probably because of the lower contribution to lumen acidification, compared with FLV, as reflected in the results of electrochromic shift analysis.
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Affiliation(s)
- Ginga Shimakawa
- Graduate School of Agricultural Science, Kobe University, Kobe, Japan
- Research Center for Solar Energy Chemistry, Osaka University, Suita, Japan
- Department of Biosciences, School of Biological and Environmental Sciences, Kwansei-Gakuin University, Nishinomiya, Japan
- Core Research for Environmental Science and Technology, Japan Science and Technology Agency, Chiyoda, Japan
| | - Hitomi Hanawa
- Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Shinya Wada
- Graduate School of Agricultural Science, Kobe University, Kobe, Japan
- Core Research for Environmental Science and Technology, Japan Science and Technology Agency, Chiyoda, Japan
| | - Guy T. Hanke
- School of Biochemistry and Chemistry, Queen Mary University of London, London, United Kingdom
| | - Yusuke Matsuda
- Department of Biosciences, School of Biological and Environmental Sciences, Kwansei-Gakuin University, Nishinomiya, Japan
| | - Chikahiro Miyake
- Graduate School of Agricultural Science, Kobe University, Kobe, Japan
- Core Research for Environmental Science and Technology, Japan Science and Technology Agency, Chiyoda, Japan
- *Correspondence: Chikahiro Miyake,
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46
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Guinea Diaz M, Nikkanen L, Himanen K, Toivola J, Rintamäki E. Two chloroplast thioredoxin systems differentially modulate photosynthesis in Arabidopsis depending on light intensity and leaf age. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 104:718-734. [PMID: 32772439 PMCID: PMC7693050 DOI: 10.1111/tpj.14959] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 07/10/2020] [Accepted: 07/13/2020] [Indexed: 05/10/2023]
Abstract
Various regulatory mechanisms have evolved in plants to optimize photosynthetic activity under fluctuating light. Thioredoxins (TRX) are members of the regulatory network balancing activities of light and carbon fixation reactions in chloroplasts. We have studied the impact of two chloroplast TRX systems, the ferredoxin-dependent TRX reductase (FTR) and the NADPH-dependent TRX reductase C (NTRC) on regulation of photosynthesis by mutants lacking or overexpressing a component of either system. Plants were subjected to image-based phenotyping and chlorophyll fluorescence measurements that allow long-term monitoring of the development and photosynthetic activity of the rosettes, respectively. Our experiments demonstrate that NTRC and FTR systems respond differently to variation of light intensity. NTRC was an indispensable regulator of photosynthesis in young leaves, at light-intensity transitions and under low light intensities limiting photosynthesis, whereas steady-state exposure of plants to growth or higher light intensities diminished the need of NTRC in regulation of photosynthesis. In fluctuating light, overexpression of NTRC increased the quantum yield of Photosystem II (YII) at low light and stimulated the relaxation of non-photochemical quenching (NPQ) after high light exposure, indicating that overexpression of NTRC improves leaf capacity to convert light energy to chemical energy under these conditions. Overexpression of chimeric protein (NTR-TRXf) containing both the thioredoxin reductase and TRXf activity on an ntrc mutant background, did not completely recover either growth or steady-state photosynthetic activity, whereas OE-NTR-TRXf plants exposed to fluctuating light regained the wild-type level of Y(II) and NPQ.
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Affiliation(s)
- Manuel Guinea Diaz
- Molecular Plant BiologyDepartment of BiochemistryUniversity of TurkuTurku20520Finland
| | - Lauri Nikkanen
- Molecular Plant BiologyDepartment of BiochemistryUniversity of TurkuTurku20520Finland
| | - Kristiina Himanen
- National Plant Phenotyping InfrastructureUniversity of HelsinkiHelsinki00790Finland
| | - Jouni Toivola
- Molecular Plant BiologyDepartment of BiochemistryUniversity of TurkuTurku20520Finland
| | - Eevi Rintamäki
- Molecular Plant BiologyDepartment of BiochemistryUniversity of TurkuTurku20520Finland
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47
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Tan Y, Zhang QS, Zhao W, Liu Z, Ma MY, Zhong MY, Wang MX, Xu B. Chlororespiration Serves as Photoprotection for the Photo-Inactivated Oxygen-Evolving Complex in Zostera marina, a Marine Angiosperm. PLANT & CELL PHYSIOLOGY 2020; 61:1517-1529. [PMID: 32492141 DOI: 10.1093/pcp/pcaa075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 05/28/2020] [Indexed: 06/11/2023]
Abstract
As an alternative electron sink, chlororespiration, comprising the NAD(P)H dehydrogenase complex and plastid terminal plastoquinone oxidase, may play a significant role in sustaining the redox equilibrium between stroma and thylakoid membrane. This study identified a distinct role for chlororespiration in the marine angiosperm Zostera marina, whose oxygen-evolving complex (OEC) is prone to photo-inactivation as a result of its inherent susceptibility to excess irradiation. The strong connectivity between OEC peripheral proteins and key chlororespiratory enzymes, as demonstrated in the interaction network of differentially expressed genes, suggested that the recovery of photo-inactivated OEC was connected with chlororespiration. Chlorophyll fluorescence, transcriptome and Western blot data verified a new physiological role for chlororespiration to function as photoprotection and generate a proton gradient across the thylakoid membrane for the recovery of photo-inactivated OEC. Chlororespiration was only activated in darkness following excess irradiation exposure, which might be related to electron deficiency in the electron transport chain because of the continuous impairment of the OEC. The activation of chlororespiration in Z. marina was prone to proactivity, which was also supported by the further activation of the oxidative pentose-phosphate pathway synthesizing NADPH to meet the demand of chlororespiration during darkness. This phenomenon is distinct from the common assumption that chlororespiration is prone to consuming redundant reducing power during the short transition phase from light to dark.
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Affiliation(s)
- Ying Tan
- Phycology Laboratory, Ocean School, Yantai University, Yantai 264005, PR China
| | - Quan Sheng Zhang
- Phycology Laboratory, Ocean School, Yantai University, Yantai 264005, PR China
| | - Wei Zhao
- Phycology Laboratory, Ocean School, Yantai University, Yantai 264005, PR China
| | - Zhe Liu
- Phycology Laboratory, Ocean School, Yantai University, Yantai 264005, PR China
| | - Ming Yu Ma
- Phycology Laboratory, Ocean School, Yantai University, Yantai 264005, PR China
| | - Ming Yu Zhong
- Phycology Laboratory, Ocean School, Yantai University, Yantai 264005, PR China
| | - Meng Xin Wang
- Phycology Laboratory, Ocean School, Yantai University, Yantai 264005, PR China
| | - Bin Xu
- Phycology Laboratory, Ocean School, Yantai University, Yantai 264005, PR China
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48
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Müller-Schüssele SJ, Wang R, Gütle DD, Romer J, Rodriguez-Franco M, Scholz M, Buchert F, Lüth VM, Kopriva S, Dörmann P, Schwarzländer M, Reski R, Hippler M, Meyer AJ. Chloroplasts require glutathione reductase to balance reactive oxygen species and maintain efficient photosynthesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:1140-1154. [PMID: 32365245 DOI: 10.1111/tpj.14791] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 05/27/2023]
Abstract
Thiol-based redox-regulation is vital for coordinating chloroplast functions depending on illumination and has been throroughly investigated for thioredoxin-dependent processes. In parallel, glutathione reductase (GR) maintains a highly reduced glutathione pool, enabling glutathione-mediated redox buffering. Yet, how the redox cascades of the thioredoxin and glutathione redox machineries integrate metabolic regulation and detoxification of reactive oxygen species remains largely unresolved because null mutants of plastid/mitochondrial GR are embryo-lethal in Arabidopsis thaliana. To investigate whether maintaining a highly reducing stromal glutathione redox potential (EGSH ) via GR is necessary for functional photosynthesis and plant growth, we created knockout lines of the homologous enzyme in the model moss Physcomitrella patens. In these viable mutant lines, we found decreasing photosynthetic performance and plant growth with increasing light intensities, whereas ascorbate and zeaxanthin/antheraxanthin levels were elevated. By in vivo monitoring stromal EGSH dynamics, we show that stromal EGSH is highly reducing in wild-type and clearly responsive to light, whereas an absence of GR leads to a partial glutathione oxidation, which is not rescued by light. By metabolic labelling, we reveal changing protein abundances in the GR knockout plants, pinpointing the adjustment of chloroplast proteostasis and the induction of plastid protein repair and degradation machineries. Our results indicate that the plastid thioredoxin system is not a functional backup for the plastid glutathione redox systems, whereas GR plays a critical role in maintaining efficient photosynthesis.
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Affiliation(s)
- Stefanie J Müller-Schüssele
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Friedrich-Ebert-Allee 144, Bonn, 53113, Germany
| | - Ren Wang
- Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 8, Münster, 48143, Germany
| | - Desirée D Gütle
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schänzlestrasse1, Freiburg, 79104, Germany
| | - Jill Romer
- Institute of Molecular Physiology and Biotechnology of Plants, University of Bonn, Bonn, 53115, Germany
| | - Marta Rodriguez-Franco
- Cell Biology, Faculty of Biology, University of Freiburg, Schänzlestr. 1, Freiburg, 79104, Germany
| | - Martin Scholz
- Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 8, Münster, 48143, Germany
| | - Felix Buchert
- Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 8, Münster, 48143, Germany
| | - Volker M Lüth
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schänzlestrasse1, Freiburg, 79104, Germany
| | - Stanislav Kopriva
- Botanical Institute, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, 50674, Germany
| | - Peter Dörmann
- Institute of Molecular Physiology and Biotechnology of Plants, University of Bonn, Bonn, 53115, Germany
| | - Markus Schwarzländer
- Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 8, Münster, 48143, Germany
| | - Ralf Reski
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schänzlestrasse1, Freiburg, 79104, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestrasse18, Freiburg, 79104, Germany
| | - Michael Hippler
- Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 8, Münster, 48143, Germany
- Institute of Plant Science and Resources, Okayama University, Kurashiki, 710-0046, Japan
| | - Andreas J Meyer
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Friedrich-Ebert-Allee 144, Bonn, 53113, Germany
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49
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Davletshina LN, Semin BK. pH dependence of photosystem II photoinhibition: relationship with structural transition of oxygen-evolving complex at the pH of thylakoid lumen. PHOTOSYNTHESIS RESEARCH 2020; 145:135-143. [PMID: 32602041 DOI: 10.1007/s11120-020-00769-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 06/23/2020] [Indexed: 06/11/2023]
Abstract
Ca-depleted photosystem II membranes (PSII[-Ca]) do not contain PsbP and PsbQ proteins protecting the Mn4CaO5 cluster of the PSII oxygen-evolving complex (OEC). Therefore, the Mn ions in the PSII(-Ca) membranes can be reduced by exogenous bulky reductants or the charged reductant Fe(II). We have recently found that the resistance of Mn ions in the OEC to the Fe(II) action is pH dependent and that this reductant is less effective at pH 5.7 than at pH 6.5 (Semin et al. J Photochem Photobiol B 178:192, 2018). Taking these data into account, we investigated the photoinhibition in different PSII membranes at pH 5.7 and 6.5 and found that the resistance to photoinhibition of PSII and PSII(-Ca) membranes with a Mn cluster is higher at pH 5.7 than at pH 6.5, whereas the resistance of the Mn-depleted PSII membranes is pH independent. In thylakoids, light generates the transmembrane ΔpH, leading to the acidulation of lumen that results in pH 5.7. The uncouplers (NH4Cl or nigericin) that significantly prevent acidulation increase the rate of PSII photoinhibition in thylakoids. We suggest that the structural transition in the OEC at pH 5.7 plays a role of a built-in mechanism increasing the resistance of OEC to photoinhibition under illumination, since it is accompanied by a pH decrease in lumen to 5.7. The coincidence of these pH values, i.e. lumen pH under illumination and pH of the maximal resistance of the Mn cluster to the reduction by reductants, can point at the pH-dependent mechanism of PSII self-protection from photoinactivation.
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Affiliation(s)
- L N Davletshina
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, 119234, Moscow, Russia
| | - B K Semin
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, 119234, Moscow, Russia.
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50
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Raven JA. Chloride involvement in the synthesis, functioning and repair of the photosynthetic apparatus in vivo. THE NEW PHYTOLOGIST 2020; 227:334-342. [PMID: 32170958 DOI: 10.1111/nph.16541] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 03/05/2020] [Indexed: 06/10/2023]
Abstract
Cl- has long been known as a micronutrient for oxygenic photosynthetic resulting from its role an essential cofactor for photosystem II (PSII). Evidence on the in vivo Cl- distribution in Spinacia oleracea leaves and chloroplasts shows that sufficient Cl- is present for the involvement in PSII function, as indicated by in vitro studies on, among other organisms, S. oleracea PsII. There is also sufficient Cl- to function, with K+ , in parsing the H+ electrochemical potential difference (proton motive force) across the illuminated thylakoid membrane into electrical potential difference and pH difference components. However, recent in vitro work on PSII from S. oleracea shows that oxygen evolving complex (OEC) synthesis, and resynthesis after photodamage, requires significantly higher Cl- concentrations than would satisfy the function of assembled PSII O2 evolution of the synthesised PSII with the OEC. The low Cl- affinity of OEC (re-)assembly could be a component limiting the rate of OEC (re-)assembly.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
- Climate Change Cluster, University of Technology, Ultimo, Sydney, NSW, 2007, Australia
- School of Biological Science, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
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