1
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Hoh D, Froehlich JE, Kramer DM. Redox regulation in chloroplast thylakoid lumen: The pmf changes everything, again. PLANT, CELL & ENVIRONMENT 2024; 47:2749-2765. [PMID: 38111217 DOI: 10.1111/pce.14789] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/28/2023] [Accepted: 12/05/2023] [Indexed: 12/20/2023]
Abstract
Photosynthesis is the foundation of life on Earth. However, if not well regulated, it can also generate excessive reactive oxygen species (ROS), which can cause photodamage. Regulation of photosynthesis is highly dynamic, responding to both environmental and metabolic cues, and occurs at many levels, from light capture to energy storage and metabolic processes. One general mechanism of regulation involves the reversible oxidation and reduction of protein thiol groups, which can affect the activity of enzymes and the stability of proteins. Such redox regulation has been well studied in stromal enzymes, but more recently, evidence has emerged of redox control of thylakoid lumenal enzymes. This review/hypothesis paper summarizes the latest research and discusses several open questions and challenges to achieving effective redox control in the lumen, focusing on the distinct environments and regulatory components of the thylakoid lumen, including the need to transport electrons across the thylakoid membrane, the effects of pH changes by the proton motive force (pmf) in the stromal and lumenal compartments, and the observed differences in redox states. These constraints suggest that activated oxygen species are likely to be major regulatory contributors to lumenal thiol redox regulation, with key components and processes yet to be discovered.
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Affiliation(s)
- Donghee Hoh
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
| | - John E Froehlich
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - David M Kramer
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
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2
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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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3
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Gulati A, Kokane S, Perez-Boerema A, Alleva C, Meier PF, Matsuoka R, Drew D. Structure and mechanism of the K +/H + exchanger KefC. Nat Commun 2024; 15:4751. [PMID: 38834573 PMCID: PMC11150392 DOI: 10.1038/s41467-024-49082-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 05/23/2024] [Indexed: 06/06/2024] Open
Abstract
Intracellular potassium (K+) homeostasis is fundamental to cell viability. In addition to channels, K+ levels are maintained by various ion transporters. One major family is the proton-driven K+ efflux transporters, which in gram-negative bacteria is important for detoxification and in plants is critical for efficient photosynthesis and growth. Despite their importance, the structure and molecular basis for K+-selectivity is poorly understood. Here, we report ~3.1 Å resolution cryo-EM structures of the Escherichia coli glutathione (GSH)-gated K+ efflux transporter KefC in complex with AMP, AMP/GSH and an ion-binding variant. KefC forms a homodimer similar to the inward-facing conformation of Na+/H+ antiporter NapA. By structural assignment of a coordinated K+ ion, MD simulations, and SSM-based electrophysiology, we demonstrate how ion-binding in KefC is adapted for binding a dehydrated K+ ion. KefC harbors C-terminal regulator of K+ conductance (RCK) domains, as present in some bacterial K+-ion channels. The domain-swapped helices in the RCK domains bind AMP and GSH and they inhibit transport by directly interacting with the ion-transporter module. Taken together, we propose that KefC is activated by detachment of the RCK domains and that ion selectivity exploits the biophysical properties likewise adapted by K+-ion-channels.
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Affiliation(s)
- Ashutosh Gulati
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Surabhi Kokane
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Annemarie Perez-Boerema
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Claudia Alleva
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Pascal F Meier
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Rei Matsuoka
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, SE-106 91, Stockholm, Sweden
| | - David Drew
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, SE-106 91, Stockholm, Sweden.
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4
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Lyu H, Zuo YS. Dynamic modulation of transthylakoid electric potential by chloroplast ATP synthases. Biochimie 2024; 221:27-37. [PMID: 38224902 DOI: 10.1016/j.biochi.2024.01.007] [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: 09/28/2023] [Revised: 12/07/2023] [Accepted: 01/12/2024] [Indexed: 01/17/2024]
Abstract
The light-induced transthylakoid membrane potential (ΔΨm) can function as a driving force to help catalyzing the formation of ATP molecules, proving a tight connection between ΔΨm and the ATP synthase. Naturally, a question can be raised on the effects of altered functioning of ATP synthases on regulating ΔΨm, which is attractive in the area of photosynthetic research. Lots of findings, when making efforts of solving this difficulty, can offer an in-depth understanding into the mechanism behind. However, the functional network on modulating ΔΨm is highly interdependent. It is difficult to comprehend the consequences of altered activity of ATP synthases on adjusting ΔΨm because parameters that have influences on ΔΨm would themselves be affected by ΔΨm. In this work, a computer model was applied to check the kinetic changes in polarization/depolarization across the thylakoid membrane (TM) regulated by the modified action of ATP synthases. The computing data revealed that under the extreme condition by numerically "switching off" the action of the ATP synthase, the complete inactivation of ATP synthase would markedly impede proton translocation at the cytb6f complex. Concurrently, the KEA3 (CLCe) porter, actively pumping protons into the stroma, further contributes to achieving a sustained low level of ΔΨm. Besides, the quantitative consequences on every particular component of ΔΨm adjusted by the modified functioning of ATP synthases were also explored. By employing the model, we bring evidence from the theoretical perspective that the ATP synthase is a key factor in forming a transmembrane proton loop thereby maintaining a propriate steady-state ΔΨm to meet variable environmental conditions.
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Affiliation(s)
- Hui Lyu
- School of Biological Science and Agriculture, Qiannan Normal University for Nationalities, Duyun, China.
| | - Yong-Song Zuo
- School of Biological Science and Agriculture, Qiannan Normal University for Nationalities, Duyun, China
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5
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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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6
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Völkner C, Holzner LJ, Bünger K, Szulc B, Lewis CM, Klingl A, Kunz HH. Evidence for partial functional overlap of KEA and MSL transport proteins in the chloroplast inner envelope of Arabidopsis thaliana. FEBS Lett 2024. [PMID: 38658177 DOI: 10.1002/1873-3468.14887] [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: 12/20/2023] [Revised: 03/21/2024] [Accepted: 03/23/2024] [Indexed: 04/26/2024]
Abstract
Arabidopsis thaliana possesses two different ion-export mechanisms in the plastid inner envelope membrane. Due to a genome duplication, the transport proteins are encoded by partly redundant loci: K+-efflux antiporter1 (KEA1) and KEA2 and mechanosensitive channel of small conductance-like2 (MSL2) and MSL3. Thus far, a functional link between these two mechanisms has not been established. Here, we show that kea1msl2 loss-of-function mutants exhibit phenotypes such as slow growth, reduced photosynthesis and changes in chloroplast morphology, several of which are distinct from either single mutants and do not resemble kea1kea2 or msl2msl3 double mutants. Our data suggest that KEA1 and MSL2 function in concert to maintain plastid ion homeostasis and osmoregulation. Their interplay is critical for proper chloroplast development, organelle function, and plant performance.
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Affiliation(s)
- Carsten Völkner
- Plant Biochemistry, LMU Munich, Planegg-Martinsried, Germany
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | | | - Katinka Bünger
- Plant Biochemistry, LMU Munich, Planegg-Martinsried, Germany
| | - Beata Szulc
- Plant Biochemistry, LMU Munich, Planegg-Martinsried, Germany
| | - Chance M Lewis
- School of Biological Sciences, Washington State University, Pullman, WA, USA
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7
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Wang X, Chen Z, Sui N. Sensitivity and responses of chloroplasts to salt stress in plants. FRONTIERS IN PLANT SCIENCE 2024; 15:1374086. [PMID: 38693929 PMCID: PMC11061501 DOI: 10.3389/fpls.2024.1374086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Accepted: 04/04/2024] [Indexed: 05/03/2024]
Abstract
Chloroplast, the site for photosynthesis and various biochemical reactions, is subject to many environmental stresses including salt stress, which affects chloroplast structure, photosynthetic processes, osmotic balance, ROS homeostasis, and so on. The maintenance of normal chloroplast function is essential for the survival of plants. Plants have developed different mechanisms to cope with salt-induced toxicity on chloroplasts to ensure the normal function of chloroplasts. The salt tolerance mechanism is complex and varies with plant species, so many aspects of these mechanisms are not entirely clear yet. In this review, we explore the effect of salinity on chloroplast structure and function, and discuss the adaptive mechanisms by which chloroplasts respond to salt stress. Understanding the sensitivity and responses of chloroplasts to salt stress will help us understand the important role of chloroplasts in plant salt stress adaptation and lay the foundation for enhancing plant salt tolerance.
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Affiliation(s)
| | | | - Na Sui
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, China
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8
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Uflewski M, Rindfleisch T, Korkmaz K, Tietz E, Mielke S, Correa Galvis V, Dünschede B, Luzarowski M, Skirycz A, Schwarzländer M, Strand DD, Hertle AP, Schünemann D, Walther D, Thalhammer A, Wolff M, Armbruster U. The thylakoid proton antiporter KEA3 regulates photosynthesis in response to the chloroplast energy status. Nat Commun 2024; 15:2792. [PMID: 38555362 PMCID: PMC10981695 DOI: 10.1038/s41467-024-47151-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 03/19/2024] [Indexed: 04/02/2024] Open
Abstract
Plant photosynthesis contains two functional modules, the light-driven reactions in the thylakoid membrane and the carbon-fixing reactions in the chloroplast stroma. In nature, light availability for photosynthesis often undergoes massive and rapid fluctuations. Efficient and productive use of such variable light supply requires an instant crosstalk and rapid synchronization of both functional modules. Here, we show that this communication involves the stromal exposed C-terminus of the thylakoid K+-exchange antiporter KEA3, which regulates the ΔpH across the thylakoid membrane and therefore pH-dependent photoprotection. By combining in silico, in vitro, and in vivo approaches, we demonstrate that the KEA3 C-terminus senses the energy state of the chloroplast in a pH-dependent manner and regulates transport activity in response. Together our data pinpoint a regulatory feedback loop by which the stromal energy state orchestrates light capture and photoprotection via multi-level regulation of KEA3.
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Affiliation(s)
- Michał Uflewski
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Potsdam, D-14476, Germany
| | - Tobias Rindfleisch
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Potsdam, D-14476, Germany
- Department of Physical Biochemistry, University of Potsdam, D-14476, Potsdam, Germany
- Computational Biology Unit, Department of Chemistry, University of Bergen, Bergen, Norway
| | - Kübra Korkmaz
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Potsdam, D-14476, Germany
| | - Enrico Tietz
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Potsdam, D-14476, Germany
| | - Sarah Mielke
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Potsdam, D-14476, Germany
| | - Viviana Correa Galvis
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Potsdam, D-14476, Germany
| | - Beatrix Dünschede
- Molecular Biology of Plant Organelles, Faculty of Biology and Biotechnology, Ruhr University Bochum, D-44780, Bochum, Germany
| | - Marcin Luzarowski
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Potsdam, D-14476, Germany
| | - Aleksandra Skirycz
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Potsdam, D-14476, Germany
| | - Markus Schwarzländer
- Institute of Plant Biology and Biotechnology (IBBP), Universität Münster, Schlossplatz 8, D-48143, Münster, Germany
| | - Deserah D Strand
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Potsdam, D-14476, Germany
| | - Alexander P Hertle
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Potsdam, D-14476, Germany
| | - Danja Schünemann
- Molecular Biology of Plant Organelles, Faculty of Biology and Biotechnology, Ruhr University Bochum, D-44780, Bochum, Germany
| | - Dirk Walther
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Potsdam, D-14476, Germany
| | - Anja Thalhammer
- Department of Physical Biochemistry, University of Potsdam, D-14476, Potsdam, Germany
| | - Martin Wolff
- Department of Physical Biochemistry, University of Potsdam, D-14476, Potsdam, Germany
| | - Ute Armbruster
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Potsdam, D-14476, Germany.
- Molecular Photosynthesis, Heinrich-Heine-University Düsseldorf, Universitätsstraße 1, D-40225, Düsseldorf, Germany.
- CEPLAS - Cluster of Excellence on Plant Sciences, Heinrich Heine University Düsseldorf, Universitätsstraße 1, D-40225, Düsseldorf, Germany.
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9
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The SV, Santiago JP, Pappenberger C, Hammes UZ, Tegeder M. UMAMIT44 is a key player in glutamate export from Arabidopsis chloroplasts. THE PLANT CELL 2024; 36:1119-1139. [PMID: 38092462 PMCID: PMC10980354 DOI: 10.1093/plcell/koad310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 11/15/2023] [Indexed: 04/01/2024]
Abstract
Selective partitioning of amino acids among organelles, cells, tissues, and organs is essential for cellular metabolism and plant growth. Nitrogen assimilation into glutamine and glutamate and de novo biosynthesis of most protein amino acids occur in chloroplasts; therefore, various transport mechanisms must exist to accommodate their directional efflux from the stroma to the cytosol and feed the amino acids into the extraplastidial metabolic and long-distance transport pathways. Yet, Arabidopsis (Arabidopsis thaliana) transporters functioning in plastidial export of amino acids remained undiscovered. Here, USUALLY MULTIPLE ACIDS MOVE IN AND OUT TRANSPORTER 44 (UMAMIT44) was identified and shown to function in glutamate export from Arabidopsis chloroplasts. UMAMIT44 controls glutamate homeostasis within and outside of chloroplasts and influences nitrogen partitioning from leaves to sinks. Glutamate imbalances in chloroplasts and leaves of umamit44 mutants impact cellular redox state, nitrogen and carbon metabolism, and amino acid (AA) and sucrose supply of growing sinks, leading to negative effects on plant growth. Nonetheless, the mutant lines adjust to some extent by upregulating alternative pathways for glutamate synthesis outside the plastids and by mitigating oxidative stress through the production of other amino acids and antioxidants. Overall, this study establishes that the role of UMAMIT44 in glutamate export from chloroplasts is vital for controlling nitrogen availability within source leaf cells and for sink nutrition, with an impact on growth and seed yield.
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Affiliation(s)
- Samantha Vivia The
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - James P Santiago
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Clara Pappenberger
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany
| | - Ulrich Z Hammes
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany
| | - Mechthild Tegeder
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
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10
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Liu J, Li D, Wang J, Wang Q, Guo X, Fu Q, Kear P, Zhu G, Yang X. Genome-wide characterization of the CPA gene family in potato and a preliminary functional analysis of its role in NaCl tolerance. BMC Genomics 2024; 25:144. [PMID: 38317113 PMCID: PMC10840148 DOI: 10.1186/s12864-024-10000-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 01/09/2024] [Indexed: 02/07/2024] Open
Abstract
BACKGROUND The cation/proton antiporter (CPA) superfamily plays a crucial role in regulating ion homeostasis and pH in plant cells, contributing to stress resistance. However, in potato (Solanum tuberosum L.), systematic identification and analysis of CPA genes are lacking. RESULTS A total of 33 StCPA members were identified and classified into StNHX (n = 7), StKEA (n = 6), and StCHX (n = 20) subfamilies. StCHX owned the highest number of conserved motifs, followed by StKEA and StNHX. The StNHX and StKEA subfamilies owned more exons than StCHX. NaCl stress induced the differentially expression of 19 genes in roots or leaves, among which StCHX14 and StCHX16 were specifically induced in leaves, while StCHX2 and StCHX19 were specifically expressed in the roots. A total of 11 strongly responded genes were further verified by qPCR. Six CPA family members, StNHX1, StNHX2, StNHX3, StNHX5, StNHX6 and StCHX19, were proved to transport Na+ through yeast complementation experiments. CONCLUSIONS This study provides comprehensive insights into StCPAs and their response to NaCl stress, facilitating further functional characterization.
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Affiliation(s)
- Jintao Liu
- Key Lab for Potato Biology in Universities of Yunnan, School of Life Sciences, Yunnan Normal University, Kunming, 650500, China
- Southwest United Graduate School, Kunming, 650500, China
| | - Dianjue Li
- Key Lab for Potato Biology in Universities of Yunnan, School of Life Sciences, Yunnan Normal University, Kunming, 650500, China
| | - Jing Wang
- Key Lab for Potato Biology in Universities of Yunnan, School of Life Sciences, Yunnan Normal University, Kunming, 650500, China
| | - Qian Wang
- Key Lab for Potato Biology in Universities of Yunnan, School of Life Sciences, Yunnan Normal University, Kunming, 650500, China
| | - Xiao Guo
- Institute of Vegetables, Shandong Academy of Agricultural Sciences/Molecular Biology Key Laboratory of Shandong Facility Vegetable/National Vegetable Improvement Center Shandong Sub-Center, Jinan, 250100, China
| | - Qi Fu
- Key Lab for Potato Biology in Universities of Yunnan, School of Life Sciences, Yunnan Normal University, Kunming, 650500, China
| | - Philip Kear
- International Potato Center (CIP), CIP China Center for Asia Pacific, Beijing, 100081, China
| | - Guangtao Zhu
- Key Lab for Potato Biology in Universities of Yunnan, School of Life Sciences, Yunnan Normal University, Kunming, 650500, China.
- Southwest United Graduate School, Kunming, 650500, China.
| | - Xiaohui Yang
- Institute of Vegetables, Shandong Academy of Agricultural Sciences/Molecular Biology Key Laboratory of Shandong Facility Vegetable/National Vegetable Improvement Center Shandong Sub-Center, Jinan, 250100, China.
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11
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Pecherina A, Dimitrieva A, Mudrilov M, Ladeynova M, Zanegina D, Brilkina A, Vodeneev V. Salt-Induced Early Changes in Photosynthesis Activity Caused by Root-to-Shoot Signaling in Potato. Int J Mol Sci 2024; 25:1229. [PMID: 38279229 PMCID: PMC10816847 DOI: 10.3390/ijms25021229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/09/2024] [Accepted: 01/12/2024] [Indexed: 01/28/2024] Open
Abstract
Salinity is one of the most dangerous types of stress in agriculture. Acting on the root, salinity causes changes in physiological processes in the shoot, especially photosynthesis, which is crucial for plant productivity. In our study, we used potato plants, the most important crop, to investigate the role of salt-induced signals in changes in photosynthesis activity. We found a salt-induced polyphasic decrease in photosynthesis activity, and the earliest phase started several minutes after salt addition. We found that salt addition triggered rapid hydraulic and calcium waves from root to shoot, which occurred earlier than the first phase of the photosynthesis response. The inhibition of calcium signals by lanthanum decreased with the formation of rapid changes in photosynthesis. In addition to this, a comparison of the characteristic times of signal propagation and the formation of a response revealed the role of calcium waves in the modulation of rapid changes in photosynthesis. Calcium waves are activated by the ionic component of salinity. The salt-induced decrease in transpiration corresponds in time to the second phase of the photosynthetic response, and it can be the cause of this change. The accumulation of sodium in the leaves occurs a few hours after salt addition, and it can be the cause of the long-term suppression of photosynthesis. Thus, salinity modulates photosynthetic activity in plants in different ways: both through the activation of rapid distant signals and by reducing the water input and sodium accumulation.
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Affiliation(s)
- Anna Pecherina
- Department of Biophysics, National Research Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue, 603022 Nizhny Novgorod, Russia; (A.P.); (A.D.); (M.M.); (M.L.)
| | - Anastasia Dimitrieva
- Department of Biophysics, National Research Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue, 603022 Nizhny Novgorod, Russia; (A.P.); (A.D.); (M.M.); (M.L.)
| | - Maxim Mudrilov
- Department of Biophysics, National Research Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue, 603022 Nizhny Novgorod, Russia; (A.P.); (A.D.); (M.M.); (M.L.)
| | - Maria Ladeynova
- Department of Biophysics, National Research Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue, 603022 Nizhny Novgorod, Russia; (A.P.); (A.D.); (M.M.); (M.L.)
| | - Daria Zanegina
- Department of Biochemistry and Biotechnology, National Research Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue, 603022 Nizhny Novgorod, Russia; (D.Z.); (A.B.)
| | - Anna Brilkina
- Department of Biochemistry and Biotechnology, National Research Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue, 603022 Nizhny Novgorod, Russia; (D.Z.); (A.B.)
| | - Vladimir Vodeneev
- Department of Biophysics, National Research Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue, 603022 Nizhny Novgorod, Russia; (A.P.); (A.D.); (M.M.); (M.L.)
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12
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Kuntz M, Dimnet L, Pullara S, Moyet L, Rolland N. The Main Functions of Plastids. Methods Mol Biol 2024; 2776:89-106. [PMID: 38502499 DOI: 10.1007/978-1-0716-3726-5_5] [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: 03/21/2024]
Abstract
Plastids are semi-autonomous organelles like mitochondria and derive from a cyanobacterial ancestor that was engulfed by a host cell. During evolution, they have recruited proteins originating from the nuclear genome, and only parts of their ancestral metabolic properties were conserved and optimized to limit functional redundancy with other cell compartments. Furthermore, large disparities in metabolic functions exist among various types of plastids, and the characterization of their various metabolic properties is far from being accomplished. In this review, we provide an overview of the main functions, known to be achieved by plastids or shared by plastids and other compartments of the cell. In short, plastids appear at the heart of all main plant functions.
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Affiliation(s)
- Marcel Kuntz
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS, CEA, INRAE, Univ. Grenoble Alpes, IRIG, CEA Grenoble, Grenoble, France.
| | - Laura Dimnet
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS, CEA, INRAE, Univ. Grenoble Alpes, IRIG, CEA Grenoble, Grenoble, France
| | - Sara Pullara
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS, CEA, INRAE, Univ. Grenoble Alpes, IRIG, CEA Grenoble, Grenoble, France
| | - Lucas Moyet
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS, CEA, INRAE, Univ. Grenoble Alpes, IRIG, CEA Grenoble, Grenoble, France
| | - Norbert Rolland
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS, CEA, INRAE, Univ. Grenoble Alpes, IRIG, CEA Grenoble, Grenoble, France
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13
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Knoblauch J, Waadt R, Cousins AB, Kunz HH. Probing the in situ volumes of Arabidopsis leaf plastids using three-dimensional confocal and scanning electron microscopy. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 117:332-341. [PMID: 37985241 DOI: 10.1111/tpj.16554] [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: 07/26/2023] [Revised: 10/31/2023] [Accepted: 11/08/2023] [Indexed: 11/22/2023]
Abstract
Leaf plastids harbor a plethora of biochemical reactions including photosynthesis, one of the most important metabolic pathways on Earth. Scientists are eager to unveil the physiological processes within the organelle but also their interconnection with the rest of the plant cell. An increasingly important feature of this venture is to use experimental data in the design of metabolic models. A remaining obstacle has been the limited in situ volume information of plastids and other cell organelles. To fill this gap for chloroplasts, we established three microscopy protocols delivering in situ volumes based on: (i) chlorophyll fluorescence emerging from the thylakoid membrane, (ii) a CFP marker embedded in the envelope, and (iii) calculations from serial block-face scanning electron microscopy (SBFSEM). The obtained data were corroborated by comparing wild-type data with two mutant lines affected in the plastid division machinery known to produce small and large mesophyll chloroplasts, respectively. Furthermore, we also determined the volume of the much smaller guard cell plastids. Interestingly, their volume is not governed by the same components of the division machinery which defines mesophyll plastid size. Based on our three approaches, the average volume of a mature Col-0 wild-type mesophyll chloroplasts is 93 μm3 . Wild-type guard cell plastids are approximately 18 μm3 . Lastly, our comparative analysis shows that the chlorophyll fluorescence analysis can accurately determine chloroplast volumes, providing an important tool to research groups without access to transgenic marker lines expressing genetically encoded fluorescence proteins or costly SBFSEM equipment.
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Affiliation(s)
- Jan Knoblauch
- School of Biological Sciences, Washington State University, P.O. Box 644236, Pullman, Washington, 99164-4236, USA
| | - Rainer Waadt
- Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 7, 48149, Münster, Germany
| | - Asaph B Cousins
- School of Biological Sciences, Washington State University, P.O. Box 644236, Pullman, Washington, 99164-4236, USA
| | - Hans-Henning Kunz
- School of Biological Sciences, Washington State University, P.O. Box 644236, Pullman, Washington, 99164-4236, USA
- LMU Munich, Plant Biochemistry, Großhadernerstr. 2-4, 82152, Planegg-Martinsried, Germany
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14
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Ounoki R, Sóti A, Ünnep R, Sipka G, Sárvári É, Garab G, Solymosi K. Etioplasts are more susceptible to salinity stress than chloroplasts and photosynthetically active etio-chloroplasts of wheat (Triticum aestivum L.). PHYSIOLOGIA PLANTARUM 2023; 175:e14100. [PMID: 38148250 DOI: 10.1111/ppl.14100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/05/2023] [Accepted: 11/06/2023] [Indexed: 12/28/2023]
Abstract
High soil salinity is a global problem in agriculture that directly affects seed germination and the development of the seedlings sown deep in the soil. To study how salinity affected plastid ultrastructure, leaf segments of 11-day-old light- and dark-grown (etiolated) wheat (Triticum aestivum L. cv. Mv Béres) seedlings were floated on Hoagland solution, 600 mM KCl:NaCl (1:1) salt or isosmotic polyethylene glycol solution for 4 h in the dark. Light-grown seedlings were also treated in the light. The same treatments were also performed on etio-chloroplasts of etiolated seedlings greened for different time periods. Salt stress induced slight to strong changes in the relative chlorophyll content, photosynthetic activity, and organization of thylakoid complexes. Measurements of malondialdehyde contents and high-temperature thermoluminescence indicated significantly increased oxidative stress and lipid peroxidation under salt treatment, except for light-grown leaves treated in the dark. In chloroplasts of leaf segments treated in the light, slight shrinkage of grana (determined by transmission electron microscopy and small-angle neutron scattering) was observed, while a swelling of the (pro)thylakoid lumen was observed in etioplasts. Salt-induced swelling disappeared after the onset of photosynthesis after 4 h of greening. Osmotic stress caused no significant alterations in plastid structure and only mild changes in their activities, indicating that the swelling of the (pro)thylakoid lumen and the physiological effects of salinity are rather associated with the ionic component of salt stress. Our data indicate that etioplasts of dark-germinated wheat seedlings are the most sensitive to salt stress, especially at the early stages of their greening.
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Affiliation(s)
- Roumaissa Ounoki
- Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Adél Sóti
- Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Renáta Ünnep
- Neutron Spectroscopy Department, HUN-REN Centre for Energy Research, Budapest, Hungary
| | - Gábor Sipka
- Institute of Plant Biology, HUN-REN Biological Research Center, Szeged, Hungary
| | - Éva Sárvári
- Department of Plant Physiology and Molecular Plant Biology, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Győző Garab
- Institute of Plant Biology, HUN-REN Biological Research Center, Szeged, Hungary
- Department of Physics, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Katalin Solymosi
- Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary
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15
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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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16
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Sóti A, Ounoki R, Kósa A, Mysliwa-Kurdziel B, Sárvári É, Solymosi K. Ionic, not the osmotic component, is responsible for the salinity-induced inhibition of greening in etiolated wheat (Triticum aestivum L. cv. Mv Béres) leaves: a comparative study. PLANTA 2023; 258:102. [PMID: 37861810 PMCID: PMC10589150 DOI: 10.1007/s00425-023-04255-4] [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: 07/02/2023] [Accepted: 09/27/2023] [Indexed: 10/21/2023]
Abstract
MAIN CONCLUSION Greening was partially (in 300 mM NaCl, CaCl2, 600 mM KNO3 or KCl) or fully inhibited (in 600 mM NaCl, NaNO3 or NaCl:KCl) by the ionic and not the osmotic component of salinity. Although high soil salinity is an increasing global problem, not much is known about how direct exposure to salinity affects etiolated leaves of seedlings germinating in the soil and then reaching the surface. We investigated the effect of various salt treatments on the greening process of leaves in 8- to 11-day-old etiolated wheat (Triticum aestivum L. Mv. Béres) seedlings. Etiolated leaf segments pre-treated on different salt (600 mM NaCl:KCl 1:1, 600 mM NaCl, 600 mM KCl, 600 mM NaNO3, 600 mM KNO3, 300 mM KCl, 300 mM NaCl or 300 mM CaCl2) or isosmotic polyethylene glycol 6000 (PEG) solutions for 1.5 h in the dark and then greened for 16 h on the same solutions were studied. Leaf segments greened on PEG (osmotic stress) or on 300 mM KCl had similar chloroplasts compared to control samples greened on Hoagland solution. Slightly slower development of chloroplast structure and function (photosynthetic activity) was observed in segments greened on 300 mM NaCl or CaCl2, 600 mM KNO3 or KCl. However, etioplast-to-chloroplast transformation and chlorophyll accumulation were fully inhibited and peculiar prothylakoid swelling occurred in segments greened on 600 mM NaCl, NaNO3 or NaCl:KCl (1:1) solutions. The data indicate that not the high osmolarity of the used salt solution, but its ions, especially Na+, had the strongest negative impact on these processes.
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Affiliation(s)
- Adél Sóti
- Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Roumaissa Ounoki
- Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Annamária Kósa
- Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Beata Mysliwa-Kurdziel
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Éva Sárvári
- Department of Plant Physiology and Molecular Plant Biology, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Katalin Solymosi
- Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary.
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17
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Schwenkert S, Lo WT, Szulc B, Yip CK, Pratt AI, Cusack SA, Brandt B, Leister D, Kunz HH. Probing the physiological role of the plastid outer-envelope membrane using the oemiR plasmid collection. G3 (BETHESDA, MD.) 2023; 13:jkad187. [PMID: 37572358 PMCID: PMC10542568 DOI: 10.1093/g3journal/jkad187] [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: 07/20/2023] [Revised: 07/20/2023] [Accepted: 08/04/2023] [Indexed: 08/14/2023]
Abstract
Plastids are the site of complex biochemical pathways, most prominently photosynthesis. The organelle evolved through endosymbiosis with a cyanobacterium, which is exemplified by the outer envelope membrane that harbors more than 40 proteins in Arabidopsis. Their evolutionary conservation indicates high significance for plant cell function. While a few proteins are well-studied as part of the protein translocon complex the majority of outer envelope protein functions is unclear. Gaining a deeper functional understanding has been complicated by the lack of observable loss-of-function mutant phenotypes, which is often rooted in functional genetic redundancy. Therefore, we designed outer envelope-specific artificial micro RNAs (oemiRs) capable of downregulating transcripts from several loci simultaneously. We successfully tested oemiR function by performing a proof-of-concept screen for pale and cold-sensitive mutants. An in-depth analysis of pale mutant alleles deficient in the translocon component TOC75 using proteomics provided new insights into putative compensatory import pathways. The cold stress screen not only recapitulated 3 previously known phenotypes of cold-sensitive mutants but also identified 4 mutants of additional oemiR outer envelope loci. Altogether our study revealed a role of the outer envelope to tolerate cold conditions and showcasts the power of the oemiR collection to research the significance of outer envelope proteins.
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Affiliation(s)
- Serena Schwenkert
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität Munich, 82152 Planegg-Martinsried, Germany
| | - Wing Tung Lo
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität Munich, 82152 Planegg-Martinsried, Germany
| | - Beata Szulc
- Plant Biochemistry, Faculty of Biology, Ludwig-Maximilians-Universität Munich, 82152 Planegg-Martinsried, Germany
| | - Chun Kwan Yip
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität Munich, 82152 Planegg-Martinsried, Germany
| | - Anna I Pratt
- School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA 99164-4236, USA
| | | | - Benjamin Brandt
- Plant Biochemistry, Faculty of Biology, Ludwig-Maximilians-Universität Munich, 82152 Planegg-Martinsried, Germany
| | - Dario Leister
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität Munich, 82152 Planegg-Martinsried, Germany
| | - Hans-Henning Kunz
- Plant Biochemistry, Faculty of Biology, Ludwig-Maximilians-Universität Munich, 82152 Planegg-Martinsried, Germany
- School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA 99164-4236, USA
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18
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Zhang X, Wang L, Pan T, Wu X, Shen J, Jiang L, Tajima H, Blumwald E, Qiu QS. Plastid KEA-type cation/H + antiporters are required for vacuolar protein trafficking in Arabidopsis. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2023; 65:2157-2174. [PMID: 37252889 DOI: 10.1111/jipb.13537] [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: 05/03/2023] [Accepted: 05/28/2023] [Indexed: 06/01/2023]
Abstract
Arabidopsis plastid antiporters KEA1 and KEA2 are critical for plastid development, photosynthetic efficiency, and plant development. Here, we show that KEA1 and KEA2 are involved in vacuolar protein trafficking. Genetic analyses found that the kea1 kea2 mutants had short siliques, small seeds, and short seedlings. Molecular and biochemical assays showed that seed storage proteins were missorted out of the cell and the precursor proteins were accumulated in kea1 kea2. Protein storage vacuoles (PSVs) were smaller in kea1 kea2. Further analyses showed that endosomal trafficking in kea1 kea2 was compromised. Vacuolar sorting receptor 1 (VSR1) subcellular localizations, VSR-cargo interactions, and p24 distribution on the endoplasmic reticulum (ER) and Golgi apparatus were affected in kea1 kea2. Moreover, plastid stromule growth was reduced and plastid association with the endomembrane compartments was disrupted in kea1 kea2. Stromule growth was regulated by the cellular pH and K+ homeostasis maintained by KEA1 and KEA2. The organellar pH along the trafficking pathway was altered in kea1 kea2. Overall, KEA1 and KEA2 regulate vacuolar trafficking by controlling the function of plastid stromules via adjusting pH and K+ homeostasis.
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Affiliation(s)
- Xiao Zhang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, 810000, China
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, 524088, China
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Lanzhou University, Lanzhou, 730000, China
| | - Lu Wang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, 810000, China
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, 524088, China
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Lanzhou University, Lanzhou, 730000, China
| | - Ting Pan
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
| | - Xuexia Wu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
| | - Jinbo Shen
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, 311300, China
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Hiromi Tajima
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA
| | - Eduardo Blumwald
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA
| | - Quan-Sheng Qiu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, 810000, China
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, 524088, China
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Lanzhou University, Lanzhou, 730000, China
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19
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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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20
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Hu W, Gu H, Wang K, Lu Z, Li X, Cong R, Ren T, Lu J. Potassium deficiency stress reduces Rubisco activity in Brassica napus leaves by subcellular acidification decreasing photosynthetic rate. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 201:107912. [PMID: 37523826 DOI: 10.1016/j.plaphy.2023.107912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 07/17/2023] [Accepted: 07/24/2023] [Indexed: 08/02/2023]
Abstract
Under potassium (K) deficiency photosynthetic carboxylation capacities are limited, affecting the photosynthetic rate of plants. However, it is not clear how ionic K within plants regulates carboxylation capacities. Therefore, the photosynthetic rate (A), ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco, EC 4.1.1.39) characteristics, and cytoplasmic pH of Brassica napus leaves with different K levels were measured to evaluate the effects of K on the carboxylation capacity by regulating subcellular pH. The results showed that biochemical limitation dominates the decrease of A. There was a close positive correlation between A and the Rubisco maximum carboxylation rate (Vcmax), which was closer than that between A and the maximum electron transport rate. The thresholds of leaf K concentrations causing decreased A, Vcmax, and Rubisco initial activity were consistent and close to 1.0% in the hydroponic experiments and 1.2% in the field experiments. K deficiency resulted in decreased Rubisco activity, which reduced carboxylation capacity. Moreover, the Rubisco initial activities in vitro with sufficient K supply or under K deficiency all were significantly reduced when the pH was decreased. The cytoplasmic pH was kept neutral at 7.5 under sufficient K supply, and decreased as the leaf K concentration declined below the threshold. Acidified cytoplasmic environment caused by K deficiency could not maintain the pH balance of the chloroplasts, leading to decreased Rubisco initial activity and photosynthetic capacity.
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Affiliation(s)
- Wenshi Hu
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China; Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
| | - Hehe Gu
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Kunjiao Wang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhifeng Lu
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xiaokun Li
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Rihuan Cong
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Tao Ren
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Jianwei Lu
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
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21
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Bulychev AA, Krupenina NA, Shapiguzov SY, Alova AV. Plasma membrane-chloroplast interactions activated by the hyperpolarizing response in characean cells. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 201:107836. [PMID: 37329688 DOI: 10.1016/j.plaphy.2023.107836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 05/26/2023] [Accepted: 06/12/2023] [Indexed: 06/19/2023]
Abstract
Signaling pathways in plant cells often comprise electrical phenomena developing at the plasma membrane. The action potentials in excitable plants like characean algae have a marked influence on photosynthetic electron transport and CO2 assimilation. The internodal cells of Characeae can also generate active electrical signals of a different type. The so called hyperpolarizing response develops under the passage of electric current whose strength is comparable to physiological currents circulating between nonuniform cell regions. The plasma membrane hyperpolarization is involved in multiple physiological events in aquatic and terrestrial plants. The hyperpolarizing response may represent an unexplored tool for studying the plasma membrane-chloroplast interactions in vivo. This study shows that the hyperpolarizing response of Chara australis internodes whose plasmalemma was preliminary converted into the K+-conductive state induces transient changes in maximal (Fm') and actual (F') fluorescence yields of chloroplasts in vivo. These fluorescence transients were light dependent, suggesting their relation to photosynthetic electron and H+ transport. The cell hyperpolarization promoted H+ influx that was inactivated after a single electric stimulus. The results indicate that the plasma membrane hyperpolarization drives transmembrane ion fluxes and modifies the ionic composition of cytoplasm, which indirectly (via envelope transporters) affects the pH of chloroplast stroma and chlorophyll fluorescence. Remarkably, the functioning of envelope ion transporters can be revealed in short-term experiments in vivo, without growing plants on solutions with various mineral compositions.
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Affiliation(s)
| | | | | | - Anna V Alova
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia.
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22
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Pahuja S, Bheri M, Bisht D, Pandey GK. Calcium signalling components underlying NPK homeostasis: potential avenues for exploration. Biochem J 2023; 480:1015-1034. [PMID: 37418287 DOI: 10.1042/bcj20230156] [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: 04/23/2023] [Revised: 06/06/2023] [Accepted: 06/19/2023] [Indexed: 07/08/2023]
Abstract
Plants require the major macronutrients, nitrogen (N), phosphorus (P) and potassium (K) for normal growth and development. Their deficiency in soil directly affects vital cellular processes, particularly root growth and architecture. Their perception, uptake and assimilation are regulated by complex signalling pathways. To overcome nutrient deficiencies, plants have developed certain response mechanisms that determine developmental and physiological adaptations. The signal transduction pathways underlying these responses involve a complex interplay of components such as nutrient transporters, transcription factors and others. In addition to their involvement in cross-talk with intracellular calcium signalling pathways, these components are also engaged in NPK sensing and homeostasis. The NPK sensing and homeostatic mechanisms hold the key to identify and understand the crucial players in nutrient regulatory networks in plants under both abiotic and biotic stresses. In this review, we discuss calcium signalling components/pathways underlying plant responses to NPK sensing, with a focus on the sensors, transporters and transcription factors involved in their respective signalling and homeostasis.
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Affiliation(s)
- Sonam Pahuja
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi 110021, India
| | - Malathi Bheri
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi 110021, India
| | - Diksha Bisht
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi 110021, India
| | - Girdhar K Pandey
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi 110021, India
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23
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Che Y, Fan D, Teng Z, Yao T, Wang Z, Zhang H, Sun G, Zhang H, Chow WS. Potassium alleviates over-reduction of the photosynthetic electron transport chain and helps to maintain photosynthetic function under salt-stress. PHYSIOLOGIA PLANTARUM 2023; 175:e13981. [PMID: 37616008 DOI: 10.1111/ppl.13981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 05/11/2023] [Accepted: 07/15/2023] [Indexed: 08/25/2023]
Abstract
Potassium ions enhance photosynthetic tolerance to salt stress. We hypothesized that potassium ions, by minimizing the trans-thylakoid proton diffusion potential difference, can alleviate over-reduction of the photosynthetic electron transport chain and maintain the functionality of the photosynthetic apparatus. This study investigated the effects of exogenous potassium on the transcription level and activity of proteins related to the photosynthetic electron-transport chain of tobacco seedlings under salt stress. Salt stress retarded the growth of seedlings and caused an outflow of potassium ions from the chloroplast. It also lowered qP (indicator of the oxidation state of QA , the primary quinone electron acceptor in Photosystem II (PSII) and YPSII (average photochemical yield of PSII in the light-adapted state) while increasing YNO+NF (nonregulatory energy dissipation in functional and nonfunctional PSII), accompanied by decreased expression of most light-harvesting, energy-transduction, and electron-transport genes. However, exogenous potassium prevented these effects due to NaCl. Interestingly, lincomycin (an inhibitor of the synthesis of chloroplast-encoded proteins in PSII) significantly diminished the alleviation effect of exogenous potassium on salt stress. We attribute the comprehensive NaCl-induced downregulation of transcription and photosynthetic activities to retrograde signaling induced by reactive oxygen species. There probably exist at least two types of retrograde signaling induced by reactive oxygen species, distinguished by their sensitivity to lincomycin. Exogenous potassium appears to exert its primary effect by ameliorating the trans-thylakoid proton diffusion potential difference via a potassium channel, thereby accelerating ATP synthesis and carbon assimilation, alleviating over-reduction of the photosynthetic electron transport chain, and maintaining the functionality of photosynthetic proteins.
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Affiliation(s)
- Yanhui Che
- College of Life Sciences, Northeast Forestry University, Harbin, China
| | - Dayong Fan
- College of Forestry, Beijing Forestry University, Beijing, China
| | - Zhiyuan Teng
- College of Life Sciences, Northeast Forestry University, Harbin, China
| | - Tongtong Yao
- College of Life Sciences, Northeast Forestry University, Harbin, China
| | - Zihan Wang
- College of Life Sciences, Northeast Forestry University, Harbin, China
| | - Hongbo Zhang
- College of Life Sciences, Northeast Forestry University, Harbin, China
| | - Guangyu Sun
- College of Life Sciences, Northeast Forestry University, Harbin, China
| | - Huihui Zhang
- College of Life Sciences, Northeast Forestry University, Harbin, China
| | - Wah Soon Chow
- Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, Australia
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24
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Rasmussen T. The Potassium Efflux System Kef: Bacterial Protection against Toxic Electrophilic Compounds. MEMBRANES 2023; 13:membranes13050465. [PMID: 37233526 DOI: 10.3390/membranes13050465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 04/21/2023] [Accepted: 04/23/2023] [Indexed: 05/27/2023]
Abstract
Kef couples the potassium efflux with proton influx in gram-negative bacteria. The resulting acidification of the cytosol efficiently prevents the killing of the bacteria by reactive electrophilic compounds. While other degradation pathways for electrophiles exist, Kef is a short-term response that is crucial for survival. It requires tight regulation since its activation comes with the burden of disturbed homeostasis. Electrophiles, entering the cell, react spontaneously or catalytically with glutathione, which is present at high concentrations in the cytosol. The resulting glutathione conjugates bind to the cytosolic regulatory domain of Kef and trigger activation while the binding of glutathione keeps the system closed. Furthermore, nucleotides can bind to this domain for stabilization or inhibition. The binding of an additional ancillary subunit, called KefF or KefG, to the cytosolic domain is required for full activation. The regulatory domain is termed K+ transport-nucleotide binding (KTN) or regulator of potassium conductance (RCK) domain, and it is also found in potassium uptake systems or channels in other oligomeric arrangements. Bacterial RosB-like transporters and K+ efflux antiporters (KEA) of plants are homologs of Kef but fulfill different functions. In summary, Kef provides an interesting and well-studied example of a highly regulated bacterial transport system.
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Affiliation(s)
- Tim Rasmussen
- Rudolf Virchow Center and Biocenter, Institute of Biochemistry II, Julius-Maximilians-Universität Würzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany
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25
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Wu Y, Cao F, Xie L, Wu F, Zhu S, Qiu C. Comparative Transcriptome Profiling Reveals Key MicroRNAs and Regulatory Mechanisms for Aluminum Tolerance in Olive. PLANTS (BASEL, SWITZERLAND) 2023; 12:plants12050978. [PMID: 36903838 PMCID: PMC10005091 DOI: 10.3390/plants12050978] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 02/18/2023] [Accepted: 02/19/2023] [Indexed: 06/06/2023]
Abstract
Aluminum toxicity (Al) is one of the major constraints to crop production in acidic soils. MicroRNAs (miRNAs) have emerged as key regulatory molecules at post-transcriptional levels, playing crucial roles in modulating various stress responses in plants. However, miRNAs and their target genes conferring Al tolerance are poorly studied in olive (Olea europaea L.). Here, genome-wide expression changes in miRNAs of the roots from two contrasting olive genotypes Zhonglan (ZL, Al-tolerant) and Frantoio selezione (FS, Al-sensitive) were investigated by high-throughput sequencing approaches. A total of 352 miRNAs were discovered in our dataset, consisting of 196 conserved miRNAs and 156 novel miRNAs. Comparative analyses showed 11 miRNAs have significantly different expression patterns in response to Al stress between ZL and FS. In silico prediction identified 10 putative target gene of these miRNAs, including MYB transcription factors, homeobox-leucine zipper (HD-Zip) proteins, auxin response factors (ARF), ATP-binding cassette (ABC) transporters and potassium efflux antiporter. Further functional classification and enrichment analysis revealed these Al-tolerance associated miRNA-mRNA pairs are mainly involved in transcriptional regulation, hormone signaling, transportation and metabolism. These findings provide new information and perspectives into the regulatory roles of miRNAs and their target for enhancing Al tolerance in olives.
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Affiliation(s)
- Yi Wu
- Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou 310058, China
| | - Fangbin Cao
- Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou 310058, China
| | - Lupeng Xie
- Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou 310058, China
| | - Feibo Wu
- Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou 310058, China
| | - Shenlong Zhu
- Institute of Crops and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Chengwei Qiu
- Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou 310058, China
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26
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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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27
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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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28
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Khan MN, Singh VP, Corpas FJ, Rodríguez Rosales MP. Closing gaps and opening new avenues for potassium research in plant biology. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 192:141-142. [PMID: 36240600 DOI: 10.1016/j.plaphy.2022.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Affiliation(s)
- M Nasir Khan
- Department of Biology, College of Haql, University of Tabuk, Tabuk, 71491, Saudi Arabia.
| | - Vijay Pratap Singh
- Plant Physiology Laboratory, Department of Botany, C.M.P. Degree College, A Constituent Post Graduate College of University of Allahabad, Prayagraj, 211002, India
| | - Francisco J Corpas
- Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, CSIC, C/Professor Albareda 1, E-18008, Granada, Spain
| | - María Pilar Rodríguez Rosales
- Departamento de Bioquímica, Biología Celulary Molecular de Plantas, Estación Experimental del Zaidín, CSIC, Granada, Spain
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29
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Gu L, Grodzinski B, Han J, Marie T, Zhang Y, Song YC, Sun Y. Granal thylakoid structure and function: explaining an enduring mystery of higher plants. THE NEW PHYTOLOGIST 2022; 236:319-329. [PMID: 35832001 PMCID: PMC9805053 DOI: 10.1111/nph.18371] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 07/07/2022] [Indexed: 05/11/2023]
Abstract
In higher plants, photosystems II and I are found in grana stacks and unstacked stroma lamellae, respectively. To connect them, electron carriers negotiate tortuous multi-media paths and are subject to macromolecular blocking. Why does evolution select an apparently unnecessary, inefficient bipartition? Here we systematically explain this perplexing phenomenon. We propose that grana stacks, acting like bellows in accordions, increase the degree of ultrastructural control on photosynthesis through thylakoid swelling/shrinking induced by osmotic water fluxes. This control coordinates with variations in stomatal conductance and the turgor of guard cells, which act like an accordion's air button. Thylakoid ultrastructural dynamics regulate macromolecular blocking/collision probability, direct diffusional pathlengths, division of function of Cytochrome b6 f complex between linear and cyclic electron transport, luminal pH via osmotic water fluxes, and the separation of pH dynamics between granal and lamellar lumens in response to environmental variations. With the two functionally asymmetrical photosystems located distantly from each other, the ultrastructural control, nonphotochemical quenching, and carbon-reaction feedbacks maximally cooperate to balance electron transport with gas exchange, provide homeostasis in fluctuating light environments, and protect photosystems in drought. Grana stacks represent a dry/high irradiance adaptation of photosynthetic machinery to improve fitness in challenging land environments. Our theory unifies many well-known but seemingly unconnected phenomena of thylakoid structure and function in higher plants.
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Affiliation(s)
- Lianhong Gu
- Environmental Sciences Division and Climate Change Science InstituteOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Bernard Grodzinski
- Department of Plant AgricultureUniversity of GuelphGuelphONN1G 2W1Canada
| | - Jimei Han
- School of Integrative Plant ScienceCornell UniversityIthacaNY14853USA
| | - Telesphore Marie
- Department of Plant AgricultureUniversity of GuelphGuelphONN1G 2W1Canada
| | | | - Yang C. Song
- Department of Hydrology and Atmospheric SciencesUniversity of ArizonaTucsonAZ85721USA
| | - Ying Sun
- School of Integrative Plant ScienceCornell UniversityIthacaNY14853USA
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30
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Che Y, Yao T, Wang H, Wang Z, Zhang H, Sun G, Zhang H. Potassium ion regulates hormone, Ca 2+ and H 2O 2 signal transduction and antioxidant activities to improve salt stress resistance in tobacco. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 186:40-51. [PMID: 35803090 DOI: 10.1016/j.plaphy.2022.06.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 06/09/2022] [Accepted: 06/25/2022] [Indexed: 06/15/2023]
Abstract
Although improvement of plant salt tolerance by potassium ions (K+) has been widely studied, whether the tolerance is mediated via hormone signaling or antioxidant systems remains to be explored. This study combined plant physiology with transcriptomic techniques to study how K+ interacts with hormones and antioxidant enzymes to improve plant salt tolerance. Tobacco was used as the test material to study the effects of exogenous potassium application on photosynthetic function, hormone signal transduction, and reactive oxygen species (ROS) production under NaCl stress. The study also evaluated the function of the Ca2+ signaling pathway in salt stress tolerance. Transcriptome data showed that 4413 up-regulated genes and 3743 down-regulated genes were found in tobacco leaves treated with NaCl compared with the control. Compared with NaCl, the down-regulated genes in tobacco leaves were significantly reduced under NaCl + KCL treatment. The results showed that NaCl stress caused oxidative damage to tobacco leaves due to increased superoxide anion (O2-) content, superoxide dismutase (SOD) dismutates superoxide anion to produce hydrogen peroxide and the accumulation of H2O2 caused by reduced ascorbate peroxidase (APX) and peroxidase (POD) activities. NaCl stress also increased abscisic acid (ABA) content in tobacco leaves, resulting in stomatal closure and reduced photosynthetic capacity. Transcriptome data showed that 5 SOD, 1 POD, 1 CAT, 5 APX, and 3 GPX genes were significantly down-regulated by the NaCl treatment. Contrarily, NaCl + KCl treatment reduced the accumulation of O2-and SOD activity but increased POD activity, thereby reducing the accumulation of H2O2 and alleviating oxidative damage. The expression of 2 SOD and 3 APX and 2 GPX genes was significantly higher in NaCl + KCl treatment than that in NaCl treatment. Sufficient K+ also increased indole acetic acid (IAA) levels in tobacco leaves under NaCl stress but reduced ABA content, promoting stomatal opening and improving the photosynthetic capacity. In conclusion, K+ can improve plant salt tolerance by alleviating oxidative damage and regulating hormone signal transduction.
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Affiliation(s)
- Yanhui Che
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, Harbin, 150040, China
| | - Tongtong Yao
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, Harbin, 150040, China
| | - Hongrui Wang
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, Harbin, 150040, China
| | - Zihan Wang
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, Harbin, 150040, China
| | - Hongbo Zhang
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, Harbin, 150040, China
| | - Guangyu Sun
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, Harbin, 150040, China
| | - Huihui Zhang
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, Harbin, 150040, China.
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31
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Mostofa MG, Rahman MM, Ghosh TK, Kabir AH, Abdelrahman M, Rahman Khan MA, Mochida K, Tran LSP. Potassium in plant physiological adaptation to abiotic stresses. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 186:279-289. [PMID: 35932652 DOI: 10.1016/j.plaphy.2022.07.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 06/30/2022] [Accepted: 07/09/2022] [Indexed: 05/02/2023]
Abstract
Potassium (K) is an integral part of plant nutrition, playing essential roles in plant growth and development. Despite its abundance in soils, the limitedly available form of K ion (K+) for plant uptake is a critical factor for agricultural production. Plants have evolved complex transport systems to maintain appropriate K+ levels in tissues under changing environmental conditions. Adequate stimulation and coordinated actions of multiple K+-channels and K+-transporters are required for nutrient homeostasis, reproductive growth, cellular signaling and stress adaptation responses in plants. Various contemporary studies revealed that K+-homeostasis plays a substantial role in plant responses and tolerance to abiotic stresses. The beneficial effects of K+ in plant responses to abiotic stresses include its roles in physiological and biochemical mechanisms involved in photosynthesis, osmoprotection, stomatal regulation, water-nutrient absorption, nutrient translocation and enzyme activation. Over the last decade, we have seen considerable breakthroughs in K research, owing to the advances in omics technologies. In this aspect, omics investigations (e.g., transcriptomics, metabolomics, and proteomics) in systems biology manner have broadened our understanding of how K+ signals are perceived, conveyed, and integrated for improving plant physiological resilience to abiotic stresses. Here, we update on how K+-uptake and K+-distribution are regulated under various types of abiotic stress. We discuss the effects of K+ on several physiological functions and the interaction of K+ with other nutrients to improve plant potential against abiotic stress-induced adverse consequences. Understanding of how K+ orchestrates physiological mechanisms and contributes to abiotic stress tolerance in plants is essential for practicing sustainable agriculture amidst the climate crisis in global agriculture.
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Affiliation(s)
- Mohammad Golam Mostofa
- Institute of Genomics for Crop Abiotic Stress Tolerance, Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79409, USA.
| | - Md Mezanur Rahman
- Institute of Genomics for Crop Abiotic Stress Tolerance, Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79409, USA
| | - Totan Kumar Ghosh
- Department of Crop Botany, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh
| | | | | | - Md Arifur Rahman Khan
- Department of Agronomy, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh
| | - Keiichi Mochida
- Bioproductivity Informatics Research Team, RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan; Microalgae Production Control Technology Laboratory, RIKEN Baton Zone Program, Yokohama 230-0045, Japan; Kihara Institute for Biological Research, Yokohama City University, Yokohama 230-0045, Japan; School of Information and Data Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Lam-Son Phan Tran
- Institute of Genomics for Crop Abiotic Stress Tolerance, Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79409, USA; Institute of Research and Development, Duy Tan University, 03 Quang Trung, Da Nang 550000, Vietnam.
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32
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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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Pi K, Luo W, Mo Z, Duan L, Ke Y, Wang P, Zeng S, Huang Y, Liu R. Overdominant expression of related genes of ion homeostasis improves K + content advantage in hybrid tobacco leaves. BMC PLANT BIOLOGY 2022; 22:335. [PMID: 35820807 PMCID: PMC9277951 DOI: 10.1186/s12870-022-03719-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Potassium(K+) plays a vital role in improving the quality of tobacco leaves. However, how to improve the potassium content of tobacco leaves has always been a difficult problem in tobacco planting. K+ content in tobacco hybrid is characterized by heterosis, which can improve the quality of tobacco leaves, but its underlying molecular genetic mechanisms remain unclear. RESULTS Through a two-year field experiment, G70×GDH11 with strong heterosis and K326×GDH11 with weak heterosis were screened out. Transcriptome analyses revealed that 80.89% and 57.28% of the differentially expressed genes (DEGs) in the strong and weak heterosis combinations exhibited an overdominant expression pattern, respectively. The genes that up-regulated the overdominant expression in the strong heterosis hybrids were significantly enriched in the ion homeostasis. Genes involved in K+ transport (KAT1/2, GORK, AKT2, and KEA3), activity regulation complex (CBL-CIPK5/6), and vacuole (TPKs) genes were overdominant expressed in strong heterosis hybrids, which contributed to K+ homeostasis and heterosis in tobacco leaves. CONCLUSIONS K+ homeostasis and accumulation in tobacco hybrids were collectively improved. The overdominant expression of K+ transport and homeostasis-related genes conducted a crucial role in the heterosis of K+ content in tobacco leaves.
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Affiliation(s)
- Kai Pi
- College of Tobacco, Guizhou University, Huaxi District, Guizhou Province, 550025, Guiyang City, P. R. China
- Key Laboratory for Tobacco Quality Research Guizhou Province, Guizhou University, 550025, Guiyang, P. R. China
| | - Wen Luo
- College of Tobacco, Guizhou University, Huaxi District, Guizhou Province, 550025, Guiyang City, P. R. China
- Key Laboratory for Tobacco Quality Research Guizhou Province, Guizhou University, 550025, Guiyang, P. R. China
| | - Zejun Mo
- College of Tobacco, Guizhou University, Huaxi District, Guizhou Province, 550025, Guiyang City, P. R. China
- Key Laboratory for Tobacco Quality Research Guizhou Province, Guizhou University, 550025, Guiyang, P. R. China
- College of Agriculture, Guizhou University, 550025, Guiyang, P. R. China
| | - Lili Duan
- College of Tobacco, Guizhou University, Huaxi District, Guizhou Province, 550025, Guiyang City, P. R. China
- Key Laboratory for Tobacco Quality Research Guizhou Province, Guizhou University, 550025, Guiyang, P. R. China
- College of Agriculture, Guizhou University, 550025, Guiyang, P. R. China
| | - Yuzhou Ke
- College of Tobacco, Guizhou University, Huaxi District, Guizhou Province, 550025, Guiyang City, P. R. China
- Key Laboratory for Tobacco Quality Research Guizhou Province, Guizhou University, 550025, Guiyang, P. R. China
| | - Pingsong Wang
- College of Tobacco, Guizhou University, Huaxi District, Guizhou Province, 550025, Guiyang City, P. R. China
- Key Laboratory for Tobacco Quality Research Guizhou Province, Guizhou University, 550025, Guiyang, P. R. China
- College of Agriculture, Guizhou University, 550025, Guiyang, P. R. China
| | - Shuaibo Zeng
- College of Tobacco, Guizhou University, Huaxi District, Guizhou Province, 550025, Guiyang City, P. R. China
- Key Laboratory for Tobacco Quality Research Guizhou Province, Guizhou University, 550025, Guiyang, P. R. China
| | - Yin Huang
- College of Tobacco, Guizhou University, Huaxi District, Guizhou Province, 550025, Guiyang City, P. R. China.
- Key Laboratory for Tobacco Quality Research Guizhou Province, Guizhou University, 550025, Guiyang, P. R. China.
| | - Renxiang Liu
- College of Tobacco, Guizhou University, Huaxi District, Guizhou Province, 550025, Guiyang City, P. R. China.
- Key Laboratory for Tobacco Quality Research Guizhou Province, Guizhou University, 550025, Guiyang, P. R. China.
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DeTar RA, Höhner R, Manavski N, Blackholm M, Meurer J, Kunz HH. Loss of SALT OVERLY SENSITIVE 1 prevents virescence in chloroplast K+/H+ EFFLUX ANTIPORTER-deficient mutants. PLANT PHYSIOLOGY 2022; 189:1220-1225. [PMID: 35325208 PMCID: PMC9237680 DOI: 10.1093/plphys/kiac142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
Defects in two plastid K+/H+ EFFLUX ANTIPORTERs in Arabidopsis can be relieved by loss of a plasma membrane Na+/H+ exchanger, presumably by altering plant K+ transport.
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Affiliation(s)
- Rachael Ann DeTar
- Plant Physiology, School of Biological Sciences, Washington State University, PO Box 644236, Pullman, Washington 99164-4236, USA
- LMU Munich, Plant Sciences, Großhaderner Str. 2-4, 82152 Planegg-Martinsried, Germany
| | - Ricarda Höhner
- Plant Physiology, School of Biological Sciences, Washington State University, PO Box 644236, Pullman, Washington 99164-4236, USA
| | - Nikolay Manavski
- LMU Munich, Plant Sciences, Großhaderner Str. 2-4, 82152 Planegg-Martinsried, Germany
| | - Marius Blackholm
- LMU Munich, Plant Sciences, Großhaderner Str. 2-4, 82152 Planegg-Martinsried, Germany
| | - Jörg Meurer
- LMU Munich, Plant Sciences, Großhaderner Str. 2-4, 82152 Planegg-Martinsried, Germany
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Ma L, Liu X, Lv W, Yang Y. Molecular Mechanisms of Plant Responses to Salt Stress. FRONTIERS IN PLANT SCIENCE 2022; 13:934877. [PMID: 35832230 PMCID: PMC9271918 DOI: 10.3389/fpls.2022.934877] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 05/23/2022] [Indexed: 06/12/2023]
Abstract
Saline-alkali soils pose an increasingly serious global threat to plant growth and productivity. Much progress has been made in elucidating how plants adapt to salt stress by modulating ion homeostasis. Understanding the molecular mechanisms that affect salt tolerance and devising strategies to develop/breed salt-resilient crops have been the primary goals of plant salt stress signaling research over the past few decades. In this review, we reflect on recent major advances in our understanding of the cellular and physiological mechanisms underlying plant responses to salt stress, especially those involving temporally and spatially defined changes in signal perception, decoding, and transduction in specific organelles or cells.
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Affiliation(s)
- Liang Ma
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xiaohong Liu
- Department of Art and Design, Taiyuan University, Taiyuan, China
| | - Wanjia Lv
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Yongqing Yang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, China
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36
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Sathee L, Jagadhesan B, Pandesha PH, Barman D, Adavi B S, Nagar S, Krishna GK, Tripathi S, Jha SK, Chinnusamy V. Genome Editing Targets for Improving Nutrient Use Efficiency and Nutrient Stress Adaptation. Front Genet 2022; 13:900897. [PMID: 35774509 PMCID: PMC9237392 DOI: 10.3389/fgene.2022.900897] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/17/2022] [Indexed: 11/22/2022] Open
Abstract
In recent years, the development of RNA-guided genome editing (CRISPR-Cas9 technology) has revolutionized plant genome editing. Under nutrient deficiency conditions, different transcription factors and regulatory gene networks work together to maintain nutrient homeostasis. Improvement in the use efficiency of nitrogen (N), phosphorus (P) and potassium (K) is essential to ensure sustainable yield with enhanced quality and tolerance to stresses. This review outlines potential targets suitable for genome editing for understanding and improving nutrient use (NtUE) efficiency and nutrient stress tolerance. The different genome editing strategies for employing crucial negative and positive regulators are also described. Negative regulators of nutrient signalling are the potential targets for genome editing, that may improve nutrient uptake and stress signalling under resource-poor conditions. The promoter engineering by CRISPR/dead (d) Cas9 (dCas9) cytosine and adenine base editing and prime editing is a successful strategy to generate precise changes. CRISPR/dCas9 system also offers the added advantage of exploiting transcriptional activators/repressors for overexpression of genes of interest in a targeted manner. CRISPR activation (CRISPRa) and CRISPR interference (CRISPRi) are variants of CRISPR in which a dCas9 dependent transcription activation or interference is achieved. dCas9-SunTag system can be employed to engineer targeted gene activation and DNA methylation in plants. The development of nutrient use efficient plants through CRISPR-Cas technology will enhance the pace of genetic improvement for nutrient stress tolerance of crops and improve the sustainability of agriculture.
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Affiliation(s)
- Lekshmy Sathee
- Division of Plant Physiology, ICAR-Indian Agricultural Research Institute, New Delhi, India
- *Correspondence: Lekshmy Sathee, ; Viswanathan Chinnusamy,
| | - B. Jagadhesan
- Division of Plant Physiology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Pratheek H. Pandesha
- Division of Plant Physiology, ICAR-Indian Agricultural Research Institute, New Delhi, India
- Roy and Diana Vagelos Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, MO, United States
| | - Dipankar Barman
- Division of Plant Physiology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Sandeep Adavi B
- Division of Plant Physiology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Shivani Nagar
- Division of Plant Physiology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - G. K. Krishna
- Department of Plant Physiology, College of Agriculture, KAU, Thrissur, India
| | - Shailesh Tripathi
- Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Shailendra K. Jha
- Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Viswanathan Chinnusamy
- Division of Plant Physiology, ICAR-Indian Agricultural Research Institute, New Delhi, India
- *Correspondence: Lekshmy Sathee, ; Viswanathan Chinnusamy,
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Schwenkert S, Fernie AR, Geigenberger P, Leister D, Möhlmann T, Naranjo B, Neuhaus HE. Chloroplasts are key players to cope with light and temperature stress. TRENDS IN PLANT SCIENCE 2022; 27:577-587. [PMID: 35012879 DOI: 10.1016/j.tplants.2021.12.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 11/16/2021] [Accepted: 12/09/2021] [Indexed: 05/04/2023]
Abstract
Under natural environmental conditions, changes in light intensity and temperature are closely interwoven, and of all organelles, only chloroplasts react strongly upon alterations of these two parameters. We review increasing evidence indicating that changes in chloroplast metabolism are critical for the comprehensive cellular answer in a challenging environment. This cellular answer starts with rapid modifications of thylakoid-located processes, followed by modifications in the stroma and transport activities across the chloroplast envelope. We propose that the 'modulators' involved contribute to plant stress tolerance and that deciphering of their characteristics is essential to understand 'acclimation'. Especially in times of climatic changes, we must gain knowledge on physiological reactions that might become instrumental for directed breeding strategies aiming to develop stress-tolerant crop plants.
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Cryo-EM structures of thylakoid-located voltage-dependent chloride channel VCCN1. Nat Commun 2022; 13:2505. [PMID: 35523970 PMCID: PMC9076864 DOI: 10.1038/s41467-022-30292-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 04/22/2022] [Indexed: 11/08/2022] Open
Abstract
In the light reaction of plant photosynthesis, modulation of electron transport chain reactions is important to maintain the efficiency of photosynthesis under a broad range of light intensities. VCCN1 was recently identified as a voltage-gated chloride channel residing in the thylakoid membrane, where it plays a key role in photoreaction tuning to avoid the generation of reactive oxygen species (ROS). Here, we present the cryo-EM structures of Malus domestica VCCN1 (MdVCCN1) in nanodiscs and detergent at 2.7 Å and 3.0 Å resolutions, respectively, and the structure-based electrophysiological analyses. VCCN1 structurally resembles its animal homolog, bestrophin, a Ca2+-gated anion channel. However, unlike bestrophin channels, VCCN1 lacks the Ca2+-binding motif but instead contains an N-terminal charged helix that is anchored to the lipid membrane through an additional amphipathic helix. Electrophysiological experiments demonstrate that these structural elements are essential for the channel activity, thus revealing the distinct activation mechanism of VCCN1.
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Basso L, Sakoda K, Kobayashi R, Yamori W, Shikanai T. Flavodiiron proteins enhance the rate of CO2 assimilation in Arabidopsis under fluctuating light intensity. PLANT PHYSIOLOGY 2022; 189:375-387. [PMID: 35171289 PMCID: PMC9070813 DOI: 10.1093/plphys/kiac064] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 01/24/2022] [Indexed: 05/19/2023]
Abstract
The proton concentration gradient (ΔpH) and membrane potential (Δψ) formed across the thylakoid membrane contribute to ATP synthesis in chloroplasts. Additionally, ΔpH downregulates photosynthetic electron transport via the acidification of the thylakoid lumen. K+ exchange antiporter 3 (KEA3) relaxes this downregulation by substituting ΔpH with Δψ in response to fluctuation of light intensity. In the Arabidopsis (Arabidopsis thaliana) line overexpressing KEA3 (KEA3ox), the rate of electron transport is elevated by accelerating the relaxation of ΔpH after a shift from high light (HL) to low light. However, the plant cannot control electron transport toward photosystem I (PSI), resulting in PSI photodamage. In this study, we crossed the KEA3ox line with the line (Flavodiiron [Flv]) expressing the Flv proteins of Physcomitrium patens. In the double transgenic line (Flv-KEA3ox), electrons overloading toward PSI were pumped out by Flv proteins. Consequently, photodamage of PSI was alleviated to the wild-type level. The rate of CO2 fixation was enhanced in Flv and Flv-KEA3ox lines during HL periods of fluctuating light, although CO2 fixation was unaffected in any transgenic lines in constant HL. Upregulation of CO2 fixation was accompanied by elevated stomatal conductance in fluctuating light. Consistent with the results of gas exchange experiments, the growth of Flv and Flv-KEA3ox plants was better than that of WT and KEA3ox plants under fluctuating light.
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Affiliation(s)
- Leonardo Basso
- Department of Botany, Graduate School of Science, Kyoto
University, Kyoto, 606-8502, Japan
| | - Kazuma Sakoda
- Institute for Sustainable Agro-Ecosystem Services, Graduate School of
Agriculture and Life Science, University of Tokyo, Tokyo, 188-0002,
Japan
- Japan Society for the Promotion of Science, Tokyo, Japan
| | - Ryouhei Kobayashi
- Department of Botany, Graduate School of Science, Kyoto
University, Kyoto, 606-8502, Japan
| | - Wataru Yamori
- Institute for Sustainable Agro-Ecosystem Services, Graduate School of
Agriculture and Life Science, University of Tokyo, Tokyo, 188-0002,
Japan
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40
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Zheng S, Su M, Shi Z, Gao H, Ma C, Zhu S, Zhang L, Wu G, Wu W, Wang J, Zhang J, Zhang T. Exogenous sucrose influences KEA1 and KEA2 to regulate abscisic acid-mediated primary root growth in Arabidopsis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 317:111209. [PMID: 35193734 DOI: 10.1016/j.plantsci.2022.111209] [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: 11/04/2021] [Revised: 01/24/2022] [Accepted: 02/03/2022] [Indexed: 06/14/2023]
Abstract
Arabidopsis K+-efflux antiporter (KEA)1 and KEA2 are chloroplast inner envelope membrane K+/H+ antiporters that play an important role in plastid development and seedling growth. However, the function of KEA1 and KEA2 during early seedling development is poorly understood. In this work, we found that in Arabidopsis, KEA1 and KEA2 mediated primary root growth by regulating photosynthesis and the ABA signaling pathway. Phenotypic analyses revealed that in the absence of sucrose, the primary root length of the kea1kea2 mutant was significantly shorter than that of the wild-type Columbia-0 (Col-0) plant. However, this phenotype could be remedied by the external application of sucrose. Meanwhile, HPLC-MS/MS results showed that in sucrose-free medium, ABA accumulation in the kea1kea2 mutant was considerably lower than that in Col-0. Transcriptome analysis revealed that many key genes involved in ABA signals were repressed in the kea1kea2 mutant. We concluded that KEA1 and KEA2 deficiency not only affected photosynthesis but was also involved in primary root growth likely through an ABA-dependent manner. This study confirmed the new function of KEA1 and KEA2 in affecting primary root growth.
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Affiliation(s)
- Sheng Zheng
- College of Life Sciences, Northwest Normal University, Lanzhou 730070, China; Academy of Plateau Science and Sustainability, Qinghai Normal University, Xining 810016, China.
| | - Min Su
- College of Life Sciences, Northwest Normal University, Lanzhou 730070, China
| | - Zhongfei Shi
- College of Life Sciences, Northwest Normal University, Lanzhou 730070, China
| | - Haixia Gao
- College of Life Sciences, Northwest Normal University, Lanzhou 730070, China
| | - Cheng Ma
- College of Life Sciences, Northwest Normal University, Lanzhou 730070, China
| | - Shan Zhu
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 311121, China
| | - Lina Zhang
- College of Life Sciences, Northwest Normal University, Lanzhou 730070, China
| | - Guofan Wu
- College of Life Sciences, Northwest Normal University, Lanzhou 730070, China
| | - Wangze Wu
- College of Life Sciences, Northwest Normal University, Lanzhou 730070, China
| | - Juan Wang
- College of Life Sciences, Northwest Normal University, Lanzhou 730070, China
| | - Jinping Zhang
- College of Life Sciences, Northwest Normal University, Lanzhou 730070, China
| | - Tengguo Zhang
- College of Life Sciences, Northwest Normal University, Lanzhou 730070, China.
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41
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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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Espinoza-Corral R, Lundquist PK. The plastoglobule-localized protein AtABC1K6 is a Mn 2+-dependent kinase necessary for timely transition to reproductive growth. J Biol Chem 2022; 298:101762. [PMID: 35202657 PMCID: PMC8956952 DOI: 10.1016/j.jbc.2022.101762] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 02/14/2022] [Accepted: 02/16/2022] [Indexed: 11/25/2022] Open
Abstract
The Absence of bc1 Complex (ABC1) is an ancient, atypical protein kinase family that emerged prior to the archaeal-eubacterial divergence. Loss-of-function mutants in ABC1 genes are linked to respiratory defects in microbes and humans and to compromised photosynthetic performance and stress tolerance in plants. However, demonstration of protein kinase activity remains elusive, hampering their study. Here, we investigate a homolog from Arabidopsis thaliana, AtABC1K6, and demonstrate in vitro autophosphorylation activity, which we replicate with a human ABC1 ortholog. We also show that AtABC1K6 protein kinase activity requires an atypical buffer composition, including Mn2+ as a divalent cation cofactor and a low salt concentration. AtABC1K6 associates with plastoglobule lipid droplets of A. thaliana chloroplasts, along with five paralogs. We show that the protein kinase activity associated with isolated A. thaliana plastoglobules was inhibited at higher salt concentrations, but could accommodate Mg2+ as well as Mn2+, indicating salt sensitivity, but not the requirement for Mn2+, may be a general characteristic of ABC1 proteins. Finally, loss of functional AtABC1K6 impairs the developmental transition from vegetative to reproductive growth. This phenotype was complemented by the wild-type sequence of AtABC1K6, but not by a kinase-dead point mutant in the unique Ala-triad of the ATP-binding pocket, demonstrating the physiological relevance of the protein's kinase activity. We suggest that ABC1s are bona fide protein kinases with a unique regulatory mechanism. Our results open the door to detailed functional and mechanistic studies of ABC1 proteins and plastoglobules.
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Affiliation(s)
- Roberto Espinoza-Corral
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA; Plant Resilience Institute, Michigan State University, East Lansing, Michigan, USA.
| | - Peter K Lundquist
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA; Plant Resilience Institute, Michigan State University, East Lansing, Michigan, USA.
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Baker CR, Stewart JJ, Amstutz CL, Ching LG, Johnson JD, Niyogi KK, Adams WW, Demmig‐Adams B. Genotype-dependent contribution of CBF transcription factors to long-term acclimation to high light and cool temperature. PLANT, CELL & ENVIRONMENT 2022; 45:392-411. [PMID: 34799867 PMCID: PMC9299779 DOI: 10.1111/pce.14231] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 11/01/2021] [Accepted: 11/05/2021] [Indexed: 06/13/2023]
Abstract
When grown under cool temperature, winter annuals upregulate photosynthetic capacity as well as freezing tolerance. Here, the role of three cold-induced C-repeat-binding factor (CBF1-3) transcription factors in photosynthetic upregulation and freezing tolerance was examined in two Arabidopsis thaliana ecotypes originating from Italy (IT) or Sweden (SW), and their corresponding CBF1-3-deficient mutant lines it:cbf123 and sw:cbf123. Photosynthetic, morphological and freezing-tolerance phenotypes, as well as gene expression profiles, were characterized in plants grown from the seedling stage under different combinations of light level and temperature. Under high light and cool (HLC) growth temperature, a greater role of CBF1-3 in IT versus SW was evident from both phenotypic and transcriptomic data, especially with respect to photosynthetic upregulation and freezing tolerance of whole plants. Overall, features of SW were consistent with a different approach to HLC acclimation than seen in IT, and an ability of SW to reach the new homeostasis through the involvement of transcriptional controls other than CBF1-3. These results provide tools and direction for further mechanistic analysis of the transcriptional control of approaches to cold acclimation suitable for either persistence through brief cold spells or for maximisation of productivity in environments with continuous low temperatures.
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Affiliation(s)
- Christopher R. Baker
- Department of Plant and Microbial Biology, Howard Hughes Medical InstituteUniversity of CaliforniaBerkeleyCaliforniaUSA
| | - Jared J. Stewart
- Department of Ecology and Evolutionary BiologyUniversity of ColoradoBoulderColoradoUSA
| | - Cynthia L. Amstutz
- Department of Plant and Microbial Biology, Howard Hughes Medical InstituteUniversity of CaliforniaBerkeleyCaliforniaUSA
| | - Lindsey G. Ching
- Department of Plant and Microbial Biology, Howard Hughes Medical InstituteUniversity of CaliforniaBerkeleyCaliforniaUSA
| | - Jeffrey D. Johnson
- Department of Plant and Microbial Biology, Howard Hughes Medical InstituteUniversity of CaliforniaBerkeleyCaliforniaUSA
| | - Krishna K. Niyogi
- Department of Plant and Microbial Biology, Howard Hughes Medical InstituteUniversity of CaliforniaBerkeleyCaliforniaUSA
- Molecular Biophysics and Integrated Bioimaging DivisionLawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
| | - William W. Adams
- Department of Ecology and Evolutionary BiologyUniversity of ColoradoBoulderColoradoUSA
| | - Barbara Demmig‐Adams
- Department of Ecology and Evolutionary BiologyUniversity of ColoradoBoulderColoradoUSA
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Walter J, Kromdijk J. Here comes the sun: How optimization of photosynthetic light reactions can boost crop yields. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:564-591. [PMID: 34962073 PMCID: PMC9302994 DOI: 10.1111/jipb.13206] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/22/2021] [Indexed: 05/22/2023]
Abstract
Photosynthesis started to evolve some 3.5 billion years ago CO2 is the substrate for photosynthesis and in the past 200-250 years, atmospheric levels have approximately doubled due to human industrial activities. However, this time span is not sufficient for adaptation mechanisms of photosynthesis to be evolutionarily manifested. Steep increases in human population, shortage of arable land and food, and climate change call for actions, now. Thanks to substantial research efforts and advances in the last century, basic knowledge of photosynthetic and primary metabolic processes can now be translated into strategies to optimize photosynthesis to its full potential in order to improve crop yields and food supply for the future. Many different approaches have been proposed in recent years, some of which have already proven successful in different crop species. Here, we summarize recent advances on modifications of the complex network of photosynthetic light reactions. These are the starting point of all biomass production and supply the energy equivalents necessary for downstream processes as well as the oxygen we breathe.
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Affiliation(s)
- Julia Walter
- Department of Plant SciencesUniversity of CambridgeCambridgeCB2 3EAUK
| | - Johannes Kromdijk
- Department of Plant SciencesUniversity of CambridgeCambridgeCB2 3EAUK
- Carl R Woese Institute for Genomic BiologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinois61801USA
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Zhang L, Zhang Z, Fang S, Liu Y, Shang X. Metabolome and Transcriptome Analyses Unravel the Molecular Regulatory Mechanisms Involved in Photosynthesis of Cyclocarya paliurus under Salt Stress. Int J Mol Sci 2022; 23:ijms23031161. [PMID: 35163101 PMCID: PMC8835658 DOI: 10.3390/ijms23031161] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/17/2022] [Accepted: 01/17/2022] [Indexed: 12/04/2022] Open
Abstract
Photosynthesis is the primary life process in nature, and how to improve photosynthetic capacity under abiotic stresses is crucial to carbon fixation and plant productivity. As a multi-functional tree species, the leaves of Cyclocarya paliurus possess antihypertensive and hypoglycemic activities. However, the regulatory mechanism involved in the photosynthetic process of C. paliurus exposed to salinity has not yet been elucidated. In this study, the photosynthetic characteristics of C. paliurus seedlings, such as photosynthetic rate (Pn), stomatal conductance (Gs), and electron transfer rate (ETR), were investigated under different salt concentrations, while the metabolome and transcriptome analyses were conducted to unravel its molecular regulatory mechanisms. Salt stress not only significantly affected photosynthetic characteristics of C. paliurus seedlings, but also severely modified the abundance of metabolites (such as fumaric acid, sedoheptulose-7-phosphate, d-fructose-1,6-bisphosphate, and 3-phospho-d-glyceroyl phosphate) involved in central carbon metabolism, and the expression of photosynthetic genes. Through the co-expression network analysis, a total of 27 transcription factors (including ERFs, IDD, DOF, MYB, RAP) were identified to regulate photosynthetic genes under salt stress. Our findings preliminarily clarify the molecular regulatory network involved in the photosynthetic process of C. paliurus under salt stress and would drive progress in improving the photosynthetic capacity and productivity of C. paliurus by molecular technology.
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Affiliation(s)
- Lei Zhang
- College of Forestry, Nanjing Forestry University, Nanjing 210037, China; (L.Z.); (Z.Z.); (Y.L.); (X.S.)
| | - Zijie Zhang
- College of Forestry, Nanjing Forestry University, Nanjing 210037, China; (L.Z.); (Z.Z.); (Y.L.); (X.S.)
| | - Shengzuo Fang
- College of Forestry, Nanjing Forestry University, Nanjing 210037, China; (L.Z.); (Z.Z.); (Y.L.); (X.S.)
- Co-Innovation Centre for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China
- Correspondence: or ; Tel.: +86-25-854-28603
| | - Yang Liu
- College of Forestry, Nanjing Forestry University, Nanjing 210037, China; (L.Z.); (Z.Z.); (Y.L.); (X.S.)
| | - Xulan Shang
- College of Forestry, Nanjing Forestry University, Nanjing 210037, China; (L.Z.); (Z.Z.); (Y.L.); (X.S.)
- Co-Innovation Centre for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China
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Codjoe JM, Miller K, Haswell ES. Plant cell mechanobiology: Greater than the sum of its parts. THE PLANT CELL 2022; 34:129-145. [PMID: 34524447 PMCID: PMC8773992 DOI: 10.1093/plcell/koab230] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 09/09/2021] [Indexed: 05/04/2023]
Abstract
The ability to sense and respond to physical forces is critical for the proper function of cells, tissues, and organisms across the evolutionary tree. Plants sense gravity, osmotic conditions, pathogen invasion, wind, and the presence of barriers in the soil, and dynamically integrate internal and external stimuli during every stage of growth and development. While the field of plant mechanobiology is growing, much is still poorly understood-including the interplay between mechanical and biochemical information at the single-cell level. In this review, we provide an overview of the mechanical properties of three main components of the plant cell and the mechanoperceptive pathways that link them, with an emphasis on areas of complexity and interaction. We discuss the concept of mechanical homeostasis, or "mechanostasis," and examine the ways in which cellular structures and pathways serve to maintain it. We argue that viewing mechanics and mechanotransduction as emergent properties of the plant cell can be a useful conceptual framework for synthesizing current knowledge and driving future research.
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Affiliation(s)
- Jennette M Codjoe
- Department of Biology and Center for Engineering Mechanobiology, Washington University in St Louis, St Louis, Missouri, 63130, USA
| | - Kari Miller
- Department of Biology and Center for Engineering Mechanobiology, Washington University in St Louis, St Louis, Missouri, 63130, USA
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Trinh MDL, Masuda S. Chloroplast pH Homeostasis for the Regulation of Photosynthesis. FRONTIERS IN PLANT SCIENCE 2022; 13:919896. [PMID: 35693183 PMCID: PMC9174948 DOI: 10.3389/fpls.2022.919896] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 05/04/2022] [Indexed: 05/16/2023]
Abstract
The pH of various chloroplast compartments, such as the thylakoid lumen and stroma, is light-dependent. Light illumination induces electron transfer in the photosynthetic apparatus, coupled with proton translocation across the thylakoid membranes, resulting in acidification and alkalization of the thylakoid lumen and stroma, respectively. Luminal acidification is crucial for inducing regulatory mechanisms that protect photosystems against photodamage caused by the overproduction of reactive oxygen species (ROS). Stromal alkalization activates enzymes involved in the Calvin-Benson-Bassham (CBB) cycle. Moreover, proton translocation across the thylakoid membranes generates a proton gradient (ΔpH) and an electric potential (ΔΨ), both of which comprise the proton motive force (pmf) that drives ATP synthase. Then, the synthesized ATP is consumed in the CBB cycle and other chloroplast metabolic pathways. In the dark, the pH of both the chloroplast stroma and thylakoid lumen becomes neutral. Despite extensive studies of the above-mentioned processes, the molecular mechanisms of how chloroplast pH can be maintained at proper levels during the light phase for efficient activation of photosynthesis and other metabolic pathways and return to neutral levels during the dark phase remain largely unclear, especially in terms of the precise control of stromal pH. The transient increase and decrease in chloroplast pH upon dark-to-light and light-to-dark transitions have been considered as signals for controlling other biological processes in plant cells. Forward and reverse genetic screening approaches recently identified new plastid proteins involved in controlling ΔpH and ΔΨ across the thylakoid membranes and chloroplast proton/ion homeostasis. These proteins have been conserved during the evolution of oxygenic phototrophs and include putative photosynthetic protein complexes, proton transporters, and/or their regulators. Herein, we summarize the recently identified protein players that control chloroplast pH and influence photosynthetic efficiency in plants.
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Affiliation(s)
- Mai Duy Luu Trinh
- Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Shinji Masuda
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
- *Correspondence: Shinji Masuda,
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Völkner C, Holzner LJ, Day PM, Ashok AD, de Vries J, Bölter B, Kunz HH. Two plastid POLLUX ion channel-like proteins are required for stress-triggered stromal Ca2+release. PLANT PHYSIOLOGY 2021; 187:2110-2125. [PMID: 34618095 PMCID: PMC8644588 DOI: 10.1093/plphys/kiab424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
Two decades ago, large cation currents were discovered in the envelope membranes of Pisum sativum L. (pea) chloroplasts. The deduced K+-permeable channel was coined fast-activating chloroplast cation channel but its molecular identity remained elusive. To reveal candidates, we mined proteomic datasets of isolated pea envelopes. Our search uncovered distant members of the nuclear POLLUX ion channel family. Since pea is not amenable to molecular genetics, we used Arabidopsis thaliana to characterize the two gene homologs. Using several independent approaches, we show that both candidates localize to the chloroplast envelope membrane. The proteins, designated PLASTID ENVELOPE ION CHANNELS (PEC1/2), form oligomers with regulator of K+ conductance domains protruding into the intermembrane space. Heterologous expression of PEC1/2 rescues yeast mutants deficient in K+ uptake. Nuclear POLLUX ion channels cofunction with Ca2+ channels to generate Ca2+ signals, critical for establishing mycorrhizal symbiosis and root development. Chloroplasts also exhibit Ca2+ transients in the stroma, probably to relay abiotic and biotic cues between plastids and the nucleus via the cytosol. Our results show that pec1pec2 loss-of-function double mutants fail to trigger the characteristic stromal Ca2+ release observed in wild-type plants exposed to external stress stimuli. Besides this molecular abnormality, pec1pec2 double mutants do not show obvious phenotypes. Future studies of PEC proteins will help to decipher the plant's stress-related Ca2+ signaling network and the role of plastids. More importantly, the discovery of PECs in the envelope membrane is another critical step towards completing the chloroplast ion transport protein inventory.
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Affiliation(s)
- Carsten Völkner
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA
| | - Lorenz Josef Holzner
- Department of Plant Biochemistry, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Philip M Day
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA
| | - Amra Dhabalia Ashok
- Department of Applied Bioinformatics, University of Goettingen, Institute for Microbiology and Genetics, 37077 Göttingen,Germany
- International Max Planck Research School for Genome Science, 37077 Göttingen, Germany
| | - Jan de Vries
- Department of Applied Bioinformatics, University of Goettingen, Institute for Microbiology and Genetics, 37077 Göttingen,Germany
- International Max Planck Research School for Genome Science, 37077 Göttingen, Germany
- Applied Bioinformatics, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Göttingen,Germany
- Campus Institute Data Science (CIDAS), University of Goettingen, 37077 Göttingen, Germany
| | - Bettina Bölter
- Department of Plant Biochemistry, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Hans-Henning Kunz
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA
- Department of Plant Biochemistry, LMU Munich, 82152 Planegg-Martinsried, Germany
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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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50
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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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