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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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2
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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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Yamamoto H, Cheuk A, Shearman J, Nixon PJ, Meier T, Shikanai T. Impact of engineering the ATP synthase rotor ring on photosynthesis in tobacco chloroplasts. PLANT PHYSIOLOGY 2023; 192:1221-1233. [PMID: 36703219 PMCID: PMC10231360 DOI: 10.1093/plphys/kiad043] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 01/05/2023] [Accepted: 01/06/2023] [Indexed: 06/01/2023]
Abstract
The chloroplast ATP synthase produces the ATP needed for photosynthesis and plant growth. The trans-membrane flow of protons through the ATP synthase rotates an oligomeric assembly of c subunits, the c-ring. The ion-to-ATP ratio in rotary F1F0-ATP synthases is defined by the number of c-subunits in the rotor c-ring. Engineering the c-ring stoichiometry is, therefore, a possible route to manipulate ATP synthesis by the ATP synthase and hence photosynthetic efficiency in plants. Here, we describe the construction of a tobacco (Nicotiana tabacum) chloroplast atpH (chloroplastic ATP synthase subunit c gene) mutant in which the c-ring stoichiometry was increased from 14 to 15 c-subunits. Although the abundance of the ATP synthase was decreased to 25% of wild-type (WT) levels, the mutant lines grew as well as WT plants and photosynthetic electron transport remained unaffected. To synthesize the necessary ATP for growth, we found that the contribution of the membrane potential to the proton motive force was enhanced to ensure a higher proton flux via the c15-ring without unwanted low pH-induced feedback inhibition of electron transport. Our work opens avenues to manipulate plant ion-to-ATP ratios with potentially beneficial consequences for photosynthesis.
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Affiliation(s)
- Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Anthony Cheuk
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington Campus, London SW7 2AZ, UK
| | - Julia Shearman
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington Campus, London SW7 2AZ, UK
| | - Peter J Nixon
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington Campus, London SW7 2AZ, UK
| | - Thomas Meier
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington Campus, London SW7 2AZ, UK
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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4
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Photosynthetic acclimation to changing environments. Biochem Soc Trans 2023; 51:473-486. [PMID: 36892145 DOI: 10.1042/bst20211245] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 02/03/2023] [Accepted: 02/21/2023] [Indexed: 03/10/2023]
Abstract
Plants are exposed to environments that fluctuate of timescales varying from seconds to months. Leaves that develop in one set of conditions optimise their metabolism to the conditions experienced, in a process called developmental acclimation. However, when plants experience a sustained change in conditions, existing leaves will also acclimate dynamically to the new conditions. Typically this process takes several days. In this review, we discuss this dynamic acclimation process, focussing on the responses of the photosynthetic apparatus to light and temperature. We briefly discuss the principal changes occurring in the chloroplast, before examining what is known, and not known, about the sensing and signalling processes that underlie acclimation, identifying likely regulators of acclimation.
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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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Yan J, Ye X, Song Y, Ren T, Wang C, Li X, Cong R, Lu Z, Lu J. Sufficient potassium improves inorganic phosphate-limited photosynthesis in Brassica napus by enhancing metabolic phosphorus fractions and Rubisco activity. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 113:416-429. [PMID: 36479950 DOI: 10.1111/tpj.16057] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 11/22/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
Crop photosynthesis (A) and productivity are often limited by a combination of nutrient stresses, such that changes in the availability of one nutrient may affect the availability of another nutrient, in turn influencing A. In this study, we examined the synergistic effects of phosphorus (P) and potassium (K) on leaf A in a nutrient amendment experiment, in which P and K were added individually or in combination to Brassica napus grown under P and K co-limitation. The data revealed that the addition of P gradually removed the dominant limiting factor (i.e. the limited availability of P) and improved leaf A. Strikingly, the addition of K synergistically improved the overall uptake of P, mainly by boosting plant growth, and compensated for the physiological demand for P by prioritizing investment in metabolic pools of P (P-containing metabolites and inorganic phosphate, Pi). The enlarged pool of metabolically active P was partially associated with the upregulation of Pi regeneration through release from triose phosphates rather than replacement of P-containing lipids. This process mitigated P restrictions on A by maintaining the ATP/NADPH and NADPH/NADP+ ratios and increasing the content and activity of Rubisco. Our findings demonstrate that sufficient K increased Pi-limited A by enhancing metabolic P fractions and Rubisco activity. Thus, ionic synergism may be exploited to mitigate nutrient-limiting factors to improve crop productivity.
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Affiliation(s)
- Jinyao Yan
- Microelement Research Center, Huazhong Agricultural University, Wuhan, 430070, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Wuhan, 430070, China
| | - Xiaolei Ye
- Microelement Research Center, Huazhong Agricultural University, Wuhan, 430070, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Wuhan, 430070, China
| | - Yi Song
- Microelement Research Center, Huazhong Agricultural University, Wuhan, 430070, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Wuhan, 430070, China
| | - Tao Ren
- Microelement Research Center, Huazhong Agricultural University, Wuhan, 430070, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Wuhan, 430070, China
| | - Chongming Wang
- Microelement Research Center, Huazhong Agricultural University, Wuhan, 430070, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Wuhan, 430070, China
| | - Xiaokun Li
- Microelement Research Center, Huazhong Agricultural University, Wuhan, 430070, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Wuhan, 430070, China
| | - Rihuan Cong
- Microelement Research Center, Huazhong Agricultural University, Wuhan, 430070, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Wuhan, 430070, China
| | - Zhifeng Lu
- Microelement Research Center, Huazhong Agricultural University, Wuhan, 430070, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Wuhan, 430070, China
| | - Jianwei Lu
- Microelement Research Center, Huazhong Agricultural University, Wuhan, 430070, China
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Wuhan, 430070, China
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Dukic E, Gollan PJ, Grebe S, Paakkarinen V, Herdean A, Aro EM, Spetea C. The Arabidopsis thylakoid chloride channel ClCe regulates ATP availability for light-harvesting complex II protein phosphorylation. FRONTIERS IN PLANT SCIENCE 2022; 13:1050355. [PMID: 36483957 PMCID: PMC9722747 DOI: 10.3389/fpls.2022.1050355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 10/31/2022] [Indexed: 06/17/2023]
Abstract
Coping with changes in light intensity is challenging for plants, but well-designed mechanisms allow them to acclimate to most unpredicted situations. The thylakoid K+/H+ antiporter KEA3 and the voltage-dependent Cl- channel VCCN1 play important roles in light acclimation by fine-tuning electron transport and photoprotection. Good evidence exists that the thylakoid Cl- channel ClCe is involved in the regulation of photosynthesis and state transitions in conditions of low light. However, a detailed mechanistic understanding of this effect is lacking. Here we report that the ClCe loss-of-function in Arabidopsis thaliana results in lower levels of phosphorylated light-harvesting complex II (LHCII) proteins as well as lower levels of the photosystem I-LHCII complexes relative to wild type (WT) in low light conditions. The phosphorylation of the photosystem II core D1/D2 proteins was less affected either in low or high light conditions. In low light conditions, the steady-state levels of ATP synthase conductivity and of the total proton flux available for ATP synthesis were lower in ClCe loss-of-function mutants, but comparable to WT at standard and high light intensity. As a long-term acclimation strategy, expression of the ClCe gene was upregulated in WT plants grown in light-limiting conditions, but not in WT plants grown in standard light even when exposed for up to 8 h to low light. Taken together, these results suggest a role of ClCe in the regulation of the ATP synthase activity which under low light conditions impacts LHCII protein phosphorylation and state transitions.
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Affiliation(s)
- Emilija Dukic
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Peter J. Gollan
- Molecular Plant Biology Unit, Department of Life Technologies, University of Turku, Turku, Finland
| | - Steffen Grebe
- Molecular Plant Biology Unit, Department of Life Technologies, University of Turku, Turku, Finland
| | - Virpi Paakkarinen
- Molecular Plant Biology Unit, Department of Life Technologies, University of Turku, Turku, Finland
| | - Andrei Herdean
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Eva-Mari Aro
- Molecular Plant Biology Unit, Department of Life Technologies, University of Turku, Turku, Finland
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
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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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9
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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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Schwenkert S, Fernie AR, Geigenberger P, Leister D, Möhlmann T, Naranjo B, Neuhaus HE. Chloroplasts are key players to cope with light and temperature stress. TRENDS IN PLANT SCIENCE 2022; 27:577-587. [PMID: 35012879 DOI: 10.1016/j.tplants.2021.12.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 11/16/2021] [Accepted: 12/09/2021] [Indexed: 05/04/2023]
Abstract
Under natural environmental conditions, changes in light intensity and temperature are closely interwoven, and of all organelles, only chloroplasts react strongly upon alterations of these two parameters. We review increasing evidence indicating that changes in chloroplast metabolism are critical for the comprehensive cellular answer in a challenging environment. This cellular answer starts with rapid modifications of thylakoid-located processes, followed by modifications in the stroma and transport activities across the chloroplast envelope. We propose that the 'modulators' involved contribute to plant stress tolerance and that deciphering of their characteristics is essential to understand 'acclimation'. Especially in times of climatic changes, we must gain knowledge on physiological reactions that might become instrumental for directed breeding strategies aiming to develop stress-tolerant crop plants.
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Ankit A, Kamali S, Singh A. Genomic & structural diversity and functional role of potassium (K +) transport proteins in plants. Int J Biol Macromol 2022; 208:844-857. [PMID: 35367275 DOI: 10.1016/j.ijbiomac.2022.03.179] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 03/11/2022] [Accepted: 03/25/2022] [Indexed: 01/03/2023]
Abstract
Potassium (K+) is an essential macronutrient for plant growth and productivity. It is the most abundant cation in plants and is involved in various cellular processes. Variable K+ availability is sensed by plant roots, consequently K+ transport proteins are activated to optimize K+ uptake. In addition to K+ uptake and translocation these proteins are involved in other important physiological processes like transmembrane voltage regulation, polar auxin transport, maintenance of Na+/K+ ratio and stomata movement during abiotic stress responses. K+ transport proteins display tremendous genomic and structural diversity in plants. Their key structural features, such as transmembrane domains, N-terminal domains, C-terminal domains and loops determine their ability of K+ uptake and transport and thus, provide functional diversity. Most K+ transporters are regulated at transcriptional and post-translational levels. Genetic manipulation of key K+ transporters/channels could be a prominent strategy for improving K+ utilization efficiency (KUE) in plants. This review discusses the genomic and structural diversity of various K+ transport proteins in plants. Also, an update on the function of K+ transport proteins and their regulatory mechanism in response to variable K+ availability, in improving KUE, biotic and abiotic stresses is provided.
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Affiliation(s)
- Ankit Ankit
- National Institute of Plant Genome Research, New Delhi 110067, India
| | | | - Amarjeet Singh
- National Institute of Plant Genome Research, New Delhi 110067, India.
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12
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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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13
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Buoso S, Musetti R, Marroni F, Calderan A, Schmidt W, Santi S. Infection by phloem-limited phytoplasma affects mineral nutrient homeostasis in tomato leaf tissues. JOURNAL OF PLANT PHYSIOLOGY 2022; 271:153659. [PMID: 35299031 DOI: 10.1016/j.jplph.2022.153659] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 01/27/2022] [Accepted: 02/22/2022] [Indexed: 06/14/2023]
Abstract
Phytoplasmas are sieve-elements restricted wall-less, pleomorphic pathogenic microorganisms causing devastating damage to over 700 plant species worldwide. The invasion of sieve elements by phytoplasmas has several consequences on nutrient transport and metabolism, anyway studies about changes of the mineral-nutrient profile following phytoplasma infections are scarce and offer contrasting results. Here, we examined changes in macro- and micronutrient concentration in tomato plant upon 'Candidatus Phytoplasma solani' infection. To investigate possible effects of 'Ca. P. solani' infection on mineral element allocation, the mineral elements were separately analysed in leaf midrib, leaf lamina and root. Moreover, we focused our analysis on the transcriptional regulation of genes encoding trans-membrane transporters of mineral nutrients. To this aim, a manually curated inventory of differentially expressed genes encoding transporters in tomato leaf midribs was mined from the transcriptional profile of healthy and infected tomato leaf midribs. Results highlighted changes in ion homeostasis in the host plant, and significant modulations at transcriptional level of genes encoding ion transporters and channels.
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Affiliation(s)
- Sara Buoso
- Department of Agricultural, Food, Environmental and Animal Sciences, Via delle Scienze 206, University of Udine, 33100, Udine, Italy.
| | - Rita Musetti
- Department of Agricultural, Food, Environmental and Animal Sciences, Via delle Scienze 206, University of Udine, 33100, Udine, Italy.
| | - Fabio Marroni
- Department of Agricultural, Food, Environmental and Animal Sciences, Via delle Scienze 206, University of Udine, 33100, Udine, Italy.
| | - Alberto Calderan
- Department of Agricultural, Food, Environmental and Animal Sciences, Via delle Scienze 206, University of Udine, 33100, Udine, Italy; Department of Life Sciences, University of Trieste, Via Licio Giorgieri, 5, 34127, Trieste, Italy.
| | - Wolfgang Schmidt
- Institute of Plant and Microbial Biology, Academia Sinica, 11529, Taipei, Taiwan; Biotechnology Center, National Chung Hsing University, 40227, Taichung, Taiwan.
| | - Simonetta Santi
- Department of Agricultural, Food, Environmental and Animal Sciences, Via delle Scienze 206, University of Udine, 33100, Udine, Italy.
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14
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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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15
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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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16
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McKay DW, McFarlane HE, Qu Y, Situmorang A, Gilliham M, Wege S. Plant Trans-Golgi Network/Early Endosome pH regulation requires Cation Chloride Cotransporter (CCC1). eLife 2022; 11:70701. [PMID: 34989335 PMCID: PMC8791640 DOI: 10.7554/elife.70701] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 01/05/2022] [Indexed: 01/04/2023] Open
Abstract
Plant cells maintain a low luminal pH in the trans-Golgi-network/early endosome (TGN/EE), the organelle in which the secretory and endocytic pathways intersect. Impaired TGN/EE pH regulation translates into severe plant growth defects. The identity of the proton pump and proton/ion antiporters that regulate TGN/EE pH have been determined, but an essential component required to complete the TGN/EE membrane transport circuit remains unidentified − a pathway for cation and anion efflux. Here, we have used complementation, genetically encoded fluorescent sensors, and pharmacological treatments to demonstrate that Arabidopsis cation chloride cotransporter (CCC1) is this missing component necessary for regulating TGN/EE pH and function. Loss of CCC1 function leads to alterations in TGN/EE-mediated processes including endocytic trafficking, exocytosis, and response to abiotic stress, consistent with the multitude of phenotypic defects observed in ccc1 knockout plants. This discovery places CCC1 as a central component of plant cellular function.
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Affiliation(s)
- Daniel W McKay
- School of Agriculture, Food and Wine, Waite Research Institute, ARC Centre of Excellence in Plant Energy Biology, University of Adelaide, Waite Campus, Adelaide, Australia
| | - Heather E McFarlane
- School of Biosciences, University of Melbourne, Melbourne, Australia.,Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - Yue Qu
- School of Agriculture, Food and Wine, Waite Research Institute, ARC Centre of Excellence in Plant Energy Biology, University of Adelaide, Waite Campus, Adelaide, Australia
| | - Apriadi Situmorang
- School of Agriculture, Food and Wine, Waite Research Institute, ARC Centre of Excellence in Plant Energy Biology, University of Adelaide, Waite Campus, Adelaide, Australia
| | - Matthew Gilliham
- School of Agriculture, Food and Wine, Waite Research Institute, ARC Centre of Excellence in Plant Energy Biology, University of Adelaide, Waite Campus, Adelaide, Australia
| | - Stefanie Wege
- School of Agriculture, Food and Wine, Waite Research Institute, ARC Centre of Excellence in Plant Energy Biology, University of Adelaide, Waite Campus, Adelaide, Australia
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17
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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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18
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Chadee A, Alber NA, Dahal K, Vanlerberghe GC. The Complementary Roles of Chloroplast Cyclic Electron Transport and Mitochondrial Alternative Oxidase to Ensure Photosynthetic Performance. FRONTIERS IN PLANT SCIENCE 2021; 12:748204. [PMID: 34650584 PMCID: PMC8505746 DOI: 10.3389/fpls.2021.748204] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 08/30/2021] [Indexed: 05/29/2023]
Abstract
Chloroplasts use light energy and a linear electron transport (LET) pathway for the coupled generation of NADPH and ATP. It is widely accepted that the production ratio of ATP to NADPH is usually less than required to fulfill the energetic needs of the chloroplast. Left uncorrected, this would quickly result in an over-reduction of the stromal pyridine nucleotide pool (i.e., high NADPH/NADP+ ratio) and under-energization of the stromal adenine nucleotide pool (i.e., low ATP/ADP ratio). These imbalances could cause metabolic bottlenecks, as well as increased generation of damaging reactive oxygen species. Chloroplast cyclic electron transport (CET) and the chloroplast malate valve could each act to prevent stromal over-reduction, albeit in distinct ways. CET avoids the NADPH production associated with LET, while the malate valve consumes the NADPH associated with LET. CET could operate by one of two different pathways, depending upon the chloroplast ATP demand. The NADH dehydrogenase-like pathway yields a higher ATP return per electron flux than the pathway involving PROTON GRADIENT REGULATION5 (PGR5) and PGR5-LIKE PHOTOSYNTHETIC PHENOTYPE1 (PGRL1). Similarly, the malate valve could couple with one of two different mitochondrial electron transport pathways, depending upon the cytosolic ATP demand. The cytochrome pathway yields a higher ATP return per electron flux than the alternative oxidase (AOX) pathway. In both Arabidopsis thaliana and Chlamydomonas reinhardtii, PGR5/PGRL1 pathway mutants have increased amounts of AOX, suggesting complementary roles for these two lesser-ATP yielding mechanisms of preventing stromal over-reduction. These two pathways may become most relevant under environmental stress conditions that lower the ATP demands for carbon fixation and carbohydrate export.
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Affiliation(s)
- Avesh Chadee
- Department of Biological Sciences, and Department of Cell and Systems Biology, University of Toronto Scarborough, Toronto, ON, Canada
| | - Nicole A. Alber
- Department of Biological Sciences, and Department of Cell and Systems Biology, University of Toronto Scarborough, Toronto, ON, Canada
| | - Keshav Dahal
- Fredericton Research and Development Centre, Agriculture and Agri-Food Canada, Fredericton, NB, Canada
| | - Greg C. Vanlerberghe
- Department of Biological Sciences, and Department of Cell and Systems Biology, University of Toronto Scarborough, Toronto, ON, Canada
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19
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Li M, Svoboda V, Davis G, Kramer D, Kunz HH, Kirchhoff H. Impact of ion fluxes across thylakoid membranes on photosynthetic electron transport and photoprotection. NATURE PLANTS 2021; 7:979-988. [PMID: 34140667 DOI: 10.1038/s41477-021-00947-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 05/18/2021] [Indexed: 05/06/2023]
Abstract
In photosynthetic thylakoid membranes the proton motive force (pmf) not only drives ATP synthesis, in addition it is central to controlling and regulating energy conversion. As a consequence, dynamic fine-tuning of the two pmf components, electrical (Δψ) and chemical (ΔpH), is an essential element for adjusting photosynthetic light reactions to changing environmental conditions. Good evidence exists that the Δψ/ΔpH partitioning is controlled by thylakoid potassium and chloride ion transporters and channels. However, a detailed mechanistic understanding of how these thylakoid ion transporter/channels control pmf partitioning is lacking. Here, we combined functional measurements on potassium and chloride ion transporter and channel loss-of-function mutants with extended mathematical simulations of photosynthetic light reactions in thylakoid membranes to obtain detailed kinetic insights into the complex interrelationship between membrane energization and ion fluxes across thylakoid membranes. The data reveal that potassium and chloride fluxes in the thylakoid lumen determined by the K+/H+ antiporter KEA3 and the voltage-gated Cl- channel VCCN1/Best1 have distinct kinetic responses that lead to characteristic and light-intensity-dependent Δψ/ΔpH oscillations. These oscillations fine-tune photoprotective mechanisms and electron transport which are particularly important during the first minutes of illumination and under fluctuating light conditions. By employing the predictive power of the model, we unravelled the functional consequences of changes in KEA3 and VCCN1 abundance and regulatory/enzymatic parameters on membrane energization and photoprotection.
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Affiliation(s)
- Meng Li
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
- School of Oceanography, University of Washington, Seattle, WA, USA
| | - Vaclav Svoboda
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Geoffry Davis
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
| | - David Kramer
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
- Department of Biochemistry, Michigan State University, East Lansing, MI, USA
| | - Hans-Henning Kunz
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA.
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20
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Gjindali A, Herrmann HA, Schwartz JM, Johnson GN, Calzadilla PI. A Holistic Approach to Study Photosynthetic Acclimation Responses of Plants to Fluctuating Light. FRONTIERS IN PLANT SCIENCE 2021; 12:668512. [PMID: 33936157 PMCID: PMC8079764 DOI: 10.3389/fpls.2021.668512] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 03/23/2021] [Indexed: 05/10/2023]
Abstract
Plants in natural environments receive light through sunflecks, the duration and distribution of these being highly variable across the day. Consequently, plants need to adjust their photosynthetic processes to avoid photoinhibition and maximize yield. Changes in the composition of the photosynthetic apparatus in response to sustained changes in the environment are referred to as photosynthetic acclimation, a process that involves changes in protein content and composition. Considering this definition, acclimation differs from regulation, which involves processes that alter the activity of individual proteins over short-time periods, without changing the abundance of those proteins. The interconnection and overlapping of the short- and long-term photosynthetic responses, which can occur simultaneously or/and sequentially over time, make the study of long-term acclimation to fluctuating light in plants challenging. In this review we identify short-term responses of plants to fluctuating light that could act as sensors and signals for acclimation responses, with the aim of understanding how plants integrate environmental fluctuations over time and tailor their responses accordingly. Mathematical modeling has the potential to integrate physiological processes over different timescales and to help disentangle short-term regulatory responses from long-term acclimation responses. We review existing mathematical modeling techniques for studying photosynthetic responses to fluctuating light and propose new methods for addressing the topic from a holistic point of view.
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Affiliation(s)
- Armida Gjindali
- Department of Earth and Environmental Sciences, Faculty of Science and Engineering, University of Manchester, Manchester, United Kingdom
| | - Helena A. Herrmann
- Department of Earth and Environmental Sciences, Faculty of Science and Engineering, University of Manchester, Manchester, United Kingdom
- Division of Evolution & Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Jean-Marc Schwartz
- Division of Evolution & Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Giles N. Johnson
- Department of Earth and Environmental Sciences, Faculty of Science and Engineering, University of Manchester, Manchester, United Kingdom
| | - Pablo I. Calzadilla
- Department of Earth and Environmental Sciences, Faculty of Science and Engineering, University of Manchester, Manchester, United Kingdom
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21
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Aranda Sicilia MN, Sánchez Romero ME, Rodríguez Rosales MP, Venema K. Plastidial transporters KEA1 and KEA2 at the inner envelope membrane adjust stromal pH in the dark. THE NEW PHYTOLOGIST 2021; 229:2080-2090. [PMID: 33111995 DOI: 10.1111/nph.17042] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 10/10/2020] [Indexed: 05/08/2023]
Abstract
Photosynthesis and carbon fixation depend critically on the regulation of pH in chloroplast compartments in the daylight and at night. While it is established that an alkaline stroma is required for carbon fixation, it is not known how alkaline stromal pH is formed, maintained or regulated. We tested whether two envelope transporters, AtKEA1 and AtKEA2, directly affected stromal pH in isolated Arabidopsis chloroplasts using the fluorescent probe 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF). External K+ -induced alkalinization of the stroma was observed in chloroplasts from wild-type (WT) plants but not from kea1kea2 mutants, suggesting that KEA1 and KEA2 mediate K+ uptake/H+ loss to modulate stromal pH. While light-stimulated alkalinization of the stroma was independent of KEA1 and KEA2, the rate of decay to neutral pH in the dark is delayed in kea1kea2 mutants. However, the dark-induced loss of a pH gradient across the thylakoid membrane was similar in WT and mutant chloroplasts. This indicates that proton influx from the cytosol mediated by envelope K+ /H+ antiporters contributes to adjustment of stromal pH upon light to dark transitions.
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Affiliation(s)
- María Nieves Aranda Sicilia
- Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, CSIC, C/ Profesor Albareda 1, Granada, 18008, Spain
| | - María Elena Sánchez Romero
- Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, CSIC, C/ Profesor Albareda 1, Granada, 18008, Spain
| | - María Pilar Rodríguez Rosales
- Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, CSIC, C/ Profesor Albareda 1, Granada, 18008, Spain
| | - Kees Venema
- Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, CSIC, C/ Profesor Albareda 1, Granada, 18008, Spain
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22
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Hepworth C, Wood WHJ, Emrich-Mills TZ, Proctor MS, Casson S, Johnson MP. Dynamic thylakoid stacking and state transitions work synergistically to avoid acceptor-side limitation of photosystem I. NATURE PLANTS 2021; 7:87-98. [PMID: 33432159 DOI: 10.1038/s41477-020-00828-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 12/04/2020] [Indexed: 05/11/2023]
Abstract
TAP38/STN7-dependent (de)phosphorylation of light-harvesting complex II (LHCII) regulates the relative excitation rates of photosystems I and II (PSI, PSII) (state transitions) and the size of the thylakoid grana stacks (dynamic thylakoid stacking). Yet, it remains unclear how changing grana size benefits photosynthesis and whether these two regulatory mechanisms function independently. Here, by comparing Arabidopsis wild-type, stn7 and tap38 plants with the psal mutant, which undergoes dynamic thylakoid stacking but lacks state transitions, we explain their distinct roles. Under low light, smaller grana increase the rate of PSI reduction and photosynthesis by reducing the diffusion distance for plastoquinol; however, this beneficial effect is only apparent when PSI/PSII excitation balance is maintained by state transitions or far-red light. Under high light, the larger grana slow plastoquinol diffusion and lower the equilibrium constant between plastocyanin and PSI, maximizing photosynthesis by avoiding PSI photoinhibition. Loss of state transitions in low light or maintenance of smaller grana in high light also both bring about a decrease in cyclic electron transfer and over-reduction of the PSI acceptor side. These results demonstrate that state transitions and dynamic thylakoid stacking work synergistically to regulate photosynthesis in variable light.
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Affiliation(s)
- Christopher Hepworth
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - William H J Wood
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - Tom Z Emrich-Mills
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - Matthew S Proctor
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - Stuart Casson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK.
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23
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Isayenkov SV, Dabravolski SA, Pan T, Shabala S. Phylogenetic Diversity and Physiological Roles of Plant Monovalent Cation/H + Antiporters. FRONTIERS IN PLANT SCIENCE 2020; 11:573564. [PMID: 33123183 PMCID: PMC7573149 DOI: 10.3389/fpls.2020.573564] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 09/02/2020] [Indexed: 05/23/2023]
Abstract
The processes of plant nutrition, stress tolerance, plant growth, and development are strongly dependent on transport of mineral nutrients across cellular membranes. Plant membrane transporters are key components of these processes. Among various membrane transport proteins, the monovalent cation proton antiporter (CPA) superfamily mediates a broad range of physiological and developmental processes such as ion and pH homeostasis, development of reproductive organs, chloroplast operation, and plant adaptation to drought and salt stresses. CPA family includes plasma membrane-bound Na+/H+ exchanger (NhaP) and intracellular Na+/H+ exchanger NHE (NHX), K+ efflux antiporter (KEA), and cation/H+ exchanger (CHX) family proteins. In this review, we have completed the phylogenetic inventory of CPA transporters and undertaken a comprehensive evolutionary analysis of their development. Compared with previous studies, we have significantly extended the range of plant species, including green and red algae and Acrogymnospermae into phylogenetic analysis. Our data suggest that the multiplication and complexation of CPA isoforms during evolution is related to land colonisation by higher plants and associated with an increase of different tissue types and development of reproductive organs. The new data extended the number of clades for all groups of CPAs, including those for NhaP/SOS, NHE/NHX, KEA, and CHX. We also critically evaluate the latest findings on the biological role, physiological functions and regulation of CPA transporters in relation to their structure and phylogenetic position. In addition, the role of CPA members in plant tolerance to various abiotic stresses is summarized, and the future priority directions for CPA studies in plants are discussed.
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Affiliation(s)
- Stanislav V. Isayenkov
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, China
- Department of Plant Food Products and Biofortification, Institute of Food Biotechnology and Genomics NAS of Ukraine, Kyiv, Ukraine
| | - Siarhei A. Dabravolski
- Department of Clinical Diagnostics, Vitebsk State Academy of Veterinary Medicine [UO VGAVM], Vitebsk, Belarus
| | - Ting Pan
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, China
| | - Sergey Shabala
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, China
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, TAS, Australia
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24
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Raven JA. Chloride involvement in the synthesis, functioning and repair of the photosynthetic apparatus in vivo. THE NEW PHYTOLOGIST 2020; 227:334-342. [PMID: 32170958 DOI: 10.1111/nph.16541] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 03/05/2020] [Indexed: 06/10/2023]
Abstract
Cl- has long been known as a micronutrient for oxygenic photosynthetic resulting from its role an essential cofactor for photosystem II (PSII). Evidence on the in vivo Cl- distribution in Spinacia oleracea leaves and chloroplasts shows that sufficient Cl- is present for the involvement in PSII function, as indicated by in vitro studies on, among other organisms, S. oleracea PsII. There is also sufficient Cl- to function, with K+ , in parsing the H+ electrochemical potential difference (proton motive force) across the illuminated thylakoid membrane into electrical potential difference and pH difference components. However, recent in vitro work on PSII from S. oleracea shows that oxygen evolving complex (OEC) synthesis, and resynthesis after photodamage, requires significantly higher Cl- concentrations than would satisfy the function of assembled PSII O2 evolution of the synthesised PSII with the OEC. The low Cl- affinity of OEC (re-)assembly could be a component limiting the rate of OEC (re-)assembly.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
- Climate Change Cluster, University of Technology, Ultimo, Sydney, NSW, 2007, Australia
- School of Biological Science, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
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25
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Wege S. Plants Increase Photosynthesis Efficiency by Lowering the Proton Gradient across the Thylakoid Membrane. PLANT PHYSIOLOGY 2020; 182:1812-1813. [PMID: 32253334 PMCID: PMC7140960 DOI: 10.1104/pp.20.00273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Affiliation(s)
- Stefanie Wege
- Australian Research Counci Centre of Excellence in Plant Energy Biology, Plant Research Centre, School of Agriculture, Food, and Wine, Waite Research Institute, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia
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