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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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52
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Channels and transporters for inorganic ions in plant mitochondria: Prediction and facts. Mitochondrion 2020; 53:224-233. [PMID: 32540403 DOI: 10.1016/j.mito.2020.05.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 05/01/2020] [Accepted: 05/22/2020] [Indexed: 02/07/2023]
Abstract
Mitochondria are crucial bioenergetic organelles for providing different metabolites, including ATP, to sustain cell growth both in animals and in plants. These organelles, delimited by two membranes (outer and inner mitochondrial membrane), maintain their function by an intensive communication with other organelles as well as with the cytosol. Transport of metabolites across the two membranes, but also that of inorganic ions, takes place through specific ion channels and transporters and plays a crucial role in ensuring an adequate ionic milieu within the mitochondria. In the present review we briefly summarize the current knowledge about plant mitochondrial ion channels and transporters in comparison to those of animal mitochondria and examine the possible molecular identity of the so far unidentified transport systems taking into account subcellular targeting predictions and data from literature.
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53
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Hennacy JH, Jonikas MC. Prospects for Engineering Biophysical CO 2 Concentrating Mechanisms into Land Plants to Enhance Yields. ANNUAL REVIEW OF PLANT BIOLOGY 2020; 71:461-485. [PMID: 32151155 PMCID: PMC7845915 DOI: 10.1146/annurev-arplant-081519-040100] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Although cyanobacteria and algae represent a small fraction of the biomass of all primary producers, their photosynthetic activity accounts for roughly half of the daily CO2 fixation that occurs on Earth. These microorganisms are able to accomplish this feat by enhancing the activity of the CO2-fixing enzyme Rubisco using biophysical CO2 concentrating mechanisms (CCMs). Biophysical CCMs operate by concentrating bicarbonate and converting it into CO2 in a compartment that houses Rubisco (in contrast with other CCMs that concentrate CO2 via an organic intermediate, such as malate in the case of C4 CCMs). This activity provides Rubisco with a high concentration of its substrate, thereby increasing its reaction rate. The genetic engineering of a biophysical CCM into land plants is being pursued as a strategy to increase crop yields. This review focuses on the progress toward understanding the molecular components of cyanobacterial and algal CCMs, as well as recent advances toward engineering these components into land plants.
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Affiliation(s)
- Jessica H Hennacy
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA; ,
| | - Martin C Jonikas
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA; ,
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Correa Galvis V, Strand DD, Messer M, Thiele W, Bethmann S, Hübner D, Uflewski M, Kaiser E, Siemiatkowska B, Morris BA, Tóth SZ, Watanabe M, Brückner F, Höfgen R, Jahns P, Schöttler MA, Armbruster U. H + Transport by K + EXCHANGE ANTIPORTER3 Promotes Photosynthesis and Growth in Chloroplast ATP Synthase Mutants. PLANT PHYSIOLOGY 2020; 182:2126-2142. [PMID: 32041909 PMCID: PMC7140953 DOI: 10.1104/pp.19.01561] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 01/27/2020] [Indexed: 05/21/2023]
Abstract
The composition of the thylakoid proton motive force (pmf) is regulated by thylakoid ion transport. Passive ion channels in the thylakoid membrane dissipate the membrane potential (Δψ) component to allow for a higher fraction of pmf stored as a proton concentration gradient (ΔpH). K+/H+ antiport across the thylakoid membrane via K+ EXCHANGE ANTIPORTER3 (KEA3) instead reduces the ΔpH fraction of the pmf. Thereby, KEA3 decreases nonphotochemical quenching (NPQ), thus allowing for higher light use efficiency, which is particularly important during transitions from high to low light. Here, we show that in the background of the Arabidopsis (Arabidopsis thaliana) chloroplast (cp)ATP synthase assembly mutant cgl160, with decreased cpATP synthase activity and increased pmf amplitude, KEA3 plays an important role for photosynthesis and plant growth under steady-state conditions. By comparing cgl160 single with cgl160 kea3 double mutants, we demonstrate that in the cgl160 background loss of KEA3 causes a strong growth penalty. This is due to a reduced photosynthetic capacity of cgl160 kea3 mutants, as these plants have a lower lumenal pH than cgl160 mutants, and thus show substantially increased pH-dependent NPQ and decreased electron transport through the cytochrome b 6 f complex. Overexpression of KEA3 in the cgl160 background reduces pH-dependent NPQ and increases photosystem II efficiency. Taken together, our data provide evidence that under conditions where cpATP synthase activity is low, a KEA3-dependent reduction of ΔpH benefits photosynthesis and growth.
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Affiliation(s)
- Viviana Correa Galvis
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Deserah D Strand
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Michaela Messer
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Wolfram Thiele
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Stephanie Bethmann
- Institute of Plant Biochemistry, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Dennis Hübner
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Michal Uflewski
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Elias Kaiser
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Beata Siemiatkowska
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Bethan A Morris
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Szilvia Z Tóth
- Institute of Plant Biology, Biological Research Centre, Szeged, Temesvári krt 62, H-6726 Szeged, Hungary
| | - Mutsumi Watanabe
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Franziska Brückner
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Rainer Höfgen
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Peter Jahns
- Institute of Plant Biochemistry, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Mark Aurel Schöttler
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Ute Armbruster
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
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Photosynthetic Response Mechanism of Soil Salinity-Induced Cross-Tolerance to Subsequent Drought Stress in Tomato Plants. PLANTS 2020; 9:plants9030363. [PMID: 32187994 PMCID: PMC7154942 DOI: 10.3390/plants9030363] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 02/28/2020] [Accepted: 03/12/2020] [Indexed: 02/06/2023]
Abstract
Soil salinization and water shortage cause ion imbalance and hyperosmoticity in plant cells, adversely impairing photosynthesis efficiency. How soil salinity-induced photosynthetic acclimation influences the cross-tolerance to drought conditions represents a promising research topic. This study was to reveal the photosynthetic mechanism of soil salinity-induced resistance to the subsequent drought stress in tomato leaves through comprehensive photosynthesis-related spectroscopy analysis. We conducted soil salinity pretreatment and subsequent drought stress experiments, including irrigation with 100 mL water, 100 mL 100 mM NaCl solution (NaCl100), 50 mL water, and 50 mL 100 mM NaCl solution (NaCl50) for five days, followed by five-day drought stress. The results showed that soil salinity treatment by NaCl decreased the rate of photosynthetic gas exchange but enhanced CO2 assimilation, along with photosystem II [PS(II)] and photosystem I [PS(I)] activity and photochemical efficiency in tomato plants compared with water pretreatment after subsequent drought stress. NaCl100 and NaCl50 had the capacity to maintain non-photochemical quenching (NPQ) of chlorophyll fluorescence and the cyclic electron (CEF) flow around PSI in tomato leaves after being subjected to subsequent drought stress, thus avoiding the decrease of photosynthetic efficiency under drought conditions. NaCl100 and NaCl50 pretreatment induced a higher proton motive force (pmf) and also alleviated the damage to the thylakoid membrane and adenosine triphosphate (ATP) synthase of tomato leaves caused by subsequent drought stress. Overall, soil salinity treatment could enhance drought resistance in tomato plants by inducing NPQ, maintaining CEF and pmf that tradeoff between photoprotection and photochemistry reactions. This study also provides a photosynthetic perspective for salt and drought cross-tolerance.
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56
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Babla M, Cai S, Chen G, Tissue DT, Cazzonelli CI, Chen ZH. Molecular Evolution and Interaction of Membrane Transport and Photoreception in Plants. Front Genet 2019; 10:956. [PMID: 31681411 PMCID: PMC6797626 DOI: 10.3389/fgene.2019.00956] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 09/06/2019] [Indexed: 12/20/2022] Open
Abstract
Light is a vital regulator that controls physiological and cellular responses to regulate plant growth, development, yield, and quality. Light is the driving force for electron and ion transport in the thylakoid membrane and other membranes of plant cells. In different plant species and cell types, light activates photoreceptors, thereby modulating plasma membrane transport. Plants maximize their growth and photosynthesis by facilitating the coordinated regulation of ion channels, pumps, and co-transporters across membranes to fine-tune nutrient uptake. The signal-transducing functions associated with membrane transporters, pumps, and channels impart a complex array of mechanisms to regulate plant responses to light. The identification of light responsive membrane transport components and understanding of their potential interaction with photoreceptors will elucidate how light-activated signaling pathways optimize plant growth, production, and nutrition to the prevailing environmental changes. This review summarizes the mechanisms underlying the physiological and molecular regulations of light-induced membrane transport and their potential interaction with photoreceptors in a plant evolutionary and nutrition context. It will shed new light on plant ecological conservation as well as agricultural production and crop quality, bringing potential nutrition and health benefits to humans and animals.
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Affiliation(s)
- Mohammad Babla
- School of Science and Health, Western Sydney University, Penrith, NSW, Australia
| | - Shengguan Cai
- School of Science and Health, Western Sydney University, Penrith, NSW, Australia
- College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Guang Chen
- College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - David T. Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | | | - Zhong-Hua Chen
- School of Science and Health, Western Sydney University, Penrith, NSW, Australia
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
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57
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Wang C, Shikanai T. Modification of Activity of the Thylakoid H +/K + Antiporter KEA3 Disturbs ∆pH-Dependent Regulation of Photosynthesis. PLANT PHYSIOLOGY 2019; 181:762-773. [PMID: 31427465 PMCID: PMC6776848 DOI: 10.1104/pp.19.00766] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 08/07/2019] [Indexed: 05/19/2023]
Abstract
The thylakoid K+ efflux antiporter 3 (KEA3) is required for regulating components of the proton motive force (pmf), proton concentration gradient (ΔpH), and membrane potential (Δψ). The Arabidopsis (Arabidopsis thaliana) disturbed proton gradient regulation mutant (dpgr) is a dominant allele of KEA3, conferring disturbed transport activity. Here, we show that overexpressing the DPGR-type KEA3 (DPGRox) retarded plant growth, whereas overexpressing the wild-type KEA3 (KEA3ox) did not. In KEA3ox lines, the contribution of Δψ to pmf was enhanced, but in DPGRox lines, the size of pmf was reduced. In DPGRox plants, proton conductivity of the thylakoid membrane (g H +) was elevated under high light, implying disturbed stoichiometry of H+/K+ antiport through DPGR-type KEA3 rather than simply enhanced activity. The ΔpH-dependent regulation consisting of thermal dissipation of excessively absorbed light energy and downregulation of cytochrome b 6 f complex activity was severely and mildly affected in DPGRox and KEA3ox plants, respectively. Consequently, photosystem I was sensitive to fluctuating light in both transgenic plants. Both photosystems were sensitive to constant high light and were slightly photodamaged even at standard growth light intensity in DPGRox plants. KEA3 regulates the components of pmf and optimizes the operation of ∆pH-dependent regulation of electron transport.
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Affiliation(s)
- Caijuan Wang
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan
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58
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Colmenero-Flores JM, Franco-Navarro JD, Cubero-Font P, Peinado-Torrubia P, Rosales MA. Chloride as a Beneficial Macronutrient in Higher Plants: New Roles and Regulation. Int J Mol Sci 2019; 20:E4686. [PMID: 31546641 PMCID: PMC6801462 DOI: 10.3390/ijms20194686] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 09/02/2019] [Indexed: 12/24/2022] Open
Abstract
Chloride (Cl-) has traditionally been considered a micronutrient largely excluded by plants due to its ubiquity and abundance in nature, its antagonism with nitrate (NO3-), and its toxicity when accumulated at high concentrations. In recent years, there has been a paradigm shift in this regard since Cl- has gone from being considered a harmful ion, accidentally absorbed through NO3- transporters, to being considered a beneficial macronutrient whose transport is finely regulated by plants. As a beneficial macronutrient, Cl- determines increased fresh and dry biomass, greater leaf expansion, increased elongation of leaf and root cells, improved water relations, higher mesophyll diffusion to CO2, and better water- and nitrogen-use efficiency. While optimal growth of plants requires the synchronic supply of both Cl- and NO3- molecules, the NO3-/Cl- plant selectivity varies between species and varieties, and in the same plant it can be modified by environmental cues such as water deficit or salinity. Recently, new genes encoding transporters mediating Cl- influx (ZmNPF6.4 and ZmNPF6.6), Cl- efflux (AtSLAH3 and AtSLAH1), and Cl- compartmentalization (AtDTX33, AtDTX35, AtALMT4, and GsCLC2) have been identified and characterized. These transporters have proven to be highly relevant for nutrition, long-distance transport and compartmentalization of Cl-, as well as for cell turgor regulation and stress tolerance in plants.
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Affiliation(s)
- José M Colmenero-Flores
- Instituto de Recursos Naturales y Agrobiología, Spanish National Research Council (CSIC), Avda Reina Mercedes 10, 41012 Sevilla, Spain.
| | - Juan D Franco-Navarro
- Instituto de Recursos Naturales y Agrobiología, Spanish National Research Council (CSIC), Avda Reina Mercedes 10, 41012 Sevilla, Spain.
| | - Paloma Cubero-Font
- Instituto de Recursos Naturales y Agrobiología, Spanish National Research Council (CSIC), Avda Reina Mercedes 10, 41012 Sevilla, Spain.
- Biochimie et physiologie Moléculaire des Plantes (BPMP), Univ Montpellier, CNRS, INRA, SupAgro, 2 place P. Viala, 34060 Montpellier, France.
| | - Procopio Peinado-Torrubia
- Instituto de Recursos Naturales y Agrobiología, Spanish National Research Council (CSIC), Avda Reina Mercedes 10, 41012 Sevilla, Spain.
| | - Miguel A Rosales
- Instituto de Recursos Naturales y Agrobiología, Spanish National Research Council (CSIC), Avda Reina Mercedes 10, 41012 Sevilla, Spain.
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59
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Zulfugarov IS, Wu G, Tovuu A, Lee CH. Effect of oxygen on the non-photochemical quenching of vascular plants and potential oxygen deficiency in the stroma of PsbS-knock-out rice. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 286:1-6. [PMID: 31300135 DOI: 10.1016/j.plantsci.2019.05.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 04/25/2019] [Accepted: 05/18/2019] [Indexed: 06/10/2023]
Abstract
The excessive and harmful light energy absorbed by the photosystem (PS) II of higher plants is dissipated as heat through a protective mechanism termed non-photochemical quenching (NPQ) of chlorophyll fluorescence. PsbS-knock-out (KO) mutants lack the trans-thylakoid proton gradient (ΔpH)-dependent part of NPQ. To elucidate the molecular mechanism of NPQ, we investigated its dependency on oxygen. The development of NPQ in wild-type (WT) rice under low-oxygen (LO) conditions was reduced to more than 50% of its original value. However, under high-oxygen (HO) conditions, the NPQ of both WT and PsbS-KO mutants recovered. Moreover, WT and PsbS-KO mutant leaves infiltrated with the ΔpH dissipating uncoupler nigericin showed increased NPQ values under HO conditions. The experiments using intact chloroplasts and protoplasts of Arabidopsis thaliana supported that the LO effects observed in rice leaves were not due to carbon dioxide deficiency. There was a noticeable 90% reduction in the half-time of P700 oxidation rate in LO-treated leaves compared with that of WT control leaves, but the HO treatment did not significantly change the half-time of P700 oxidation rate. Overall, the results obtained here indicate that the stroma of the PsbS-KO plants could be potentially under O2 deficiency. Because the functions of PsbS in rice leaves are likely to be similar to those in other higher plants, our findings offer novel insights into the role of oxygen in the development of NPQ.
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Affiliation(s)
- Ismayil S Zulfugarov
- Department of Integrated Biological Science and Department of Molecular Biology, Pusan National University, Busan 46241, Republic of Korea; Institute of Molecular Biology and Biotechnology, Azerbaijan National Academy of Sciences, Matbuat Avenue 2a, Baku AZ 1073, Azerbaijan; Department of Biology, North-Eastern Federal University, 58 Belinsky Str., Yakutsk 677-027, Republic of Sakha (Yakutia), Russian Federation
| | - Guangxi Wu
- Department of Integrated Biological Science and Department of Molecular Biology, Pusan National University, Busan 46241, Republic of Korea
| | - Altanzaya Tovuu
- Department of Integrated Biological Science and Department of Molecular Biology, Pusan National University, Busan 46241, Republic of Korea
| | - Choon-Hwan Lee
- Department of Integrated Biological Science and Department of Molecular Biology, Pusan National University, Busan 46241, Republic of Korea.
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60
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Franco-Navarro JD, Rosales MA, Cubero-Font P, Calvo P, Álvarez R, Diaz-Espejo A, Colmenero-Flores JM. Chloride as a macronutrient increases water-use efficiency by anatomically driven reduced stomatal conductance and increased mesophyll diffusion to CO 2. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 99:815-831. [PMID: 31148340 DOI: 10.1111/tpj.14423] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 05/17/2019] [Accepted: 05/22/2019] [Indexed: 05/27/2023]
Abstract
Chloride (Cl- ) has been recently described as a beneficial macronutrient, playing specific roles in promoting plant growth and water-use efficiency (WUE). However, it is still unclear how Cl- could be beneficial, especially in comparison with nitrate (NO3- ), an essential source of nitrogen that shares with Cl- similar physical and osmotic properties, as well as common transport mechanisms. In tobacco plants, macronutrient levels of Cl- specifically reduce stomatal conductance (gs ) without a concomitant reduction in the net photosynthesis rate (AN ). As stomata-mediated water loss through transpiration is inherent in the need of C3 plants to capture CO2 , simultaneous increase in photosynthesis and WUE is of great relevance to achieve a sustainable increase in C3 crop productivity. Our results showed that Cl- -mediated stimulation of larger leaf cells leads to a reduction in stomatal density, which in turn reduces gs and water consumption. Conversely, Cl- improves mesophyll diffusion conductance to CO2 (gm ) and photosynthetic performance due to a higher surface area of chloroplasts exposed to the intercellular airspace of mesophyll cells, possibly as a consequence of the stimulation of chloroplast biogenesis. A key finding of this study is the simultaneous improvement of AN and WUE due to macronutrient Cl- nutrition. This work identifies relevant and specific functions in which Cl- participates as a beneficial macronutrient for higher plants, uncovering a sustainable approach to improve crop yield.
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Affiliation(s)
- Juan D Franco-Navarro
- Instituto de Recursos Naturales y Agrobiología, CSIC, Avda Reina Mercedes 10, 41012, Sevilla, Spain
| | - Miguel A Rosales
- Instituto de Recursos Naturales y Agrobiología, CSIC, Avda Reina Mercedes 10, 41012, Sevilla, Spain
| | - Paloma Cubero-Font
- Instituto de Recursos Naturales y Agrobiología, CSIC, Avda Reina Mercedes 10, 41012, Sevilla, Spain
- Biochimie et Physiologie Moléculaire des Plantes (BPMP), Univ. Montpellier, CNRS, INRA, SupAgro, 2 Place P. Viala, Montpellier, 34060, France
| | - Purificación Calvo
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avda Reina Mercedes 6, 41012, Sevilla, Spain
| | - Rosario Álvarez
- Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universidad de Sevilla, Avda. Reina Mercedes 6, 41012, Sevilla, Spain
| | - Antonio Diaz-Espejo
- Instituto de Recursos Naturales y Agrobiología, CSIC, Avda Reina Mercedes 10, 41012, Sevilla, Spain
| | - José M Colmenero-Flores
- Instituto de Recursos Naturales y Agrobiología, CSIC, Avda Reina Mercedes 10, 41012, Sevilla, Spain
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61
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Mukherjee A, Lau CS, Walker CE, Rai AK, Prejean CI, Yates G, Emrich-Mills T, Lemoine SG, Vinyard DJ, Mackinder LCM, Moroney JV. Thylakoid localized bestrophin-like proteins are essential for the CO 2 concentrating mechanism of Chlamydomonas reinhardtii. Proc Natl Acad Sci U S A 2019; 116:16915-16920. [PMID: 31391312 DOI: 10.1073/pnas.190970611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023] Open
Abstract
The green alga Chlamydomonas reinhardtii possesses a CO2 concentrating mechanism (CCM) that helps in successful acclimation to low CO2 conditions. Current models of the CCM postulate that a series of ion transporters bring HCO3- from outside the cell to the thylakoid lumen, where the carbonic anhydrase 3 (CAH3) dehydrates accumulated HCO3- to CO2, raising the CO2 concentration for Ribulose bisphosphate carboxylase/oxygenase (Rubisco). Previously, HCO3- transporters have been identified at both the plasma membrane and the chloroplast envelope, but the transporter thought to be on the thylakoid membrane has not been identified. Three paralogous genes (BST1, BST2, and BST3) belonging to the bestrophin family have been found to be up-regulated in low CO2 conditions, and their expression is controlled by CIA5, a transcription factor that controls many CCM genes. YFP fusions demonstrate that all 3 proteins are located on the thylakoid membrane, and interactome studies indicate that they might associate with chloroplast CCM components. A single mutant defective in BST3 has near-normal growth on low CO2, indicating that the 3 bestrophin-like proteins may have redundant functions. Therefore, an RNA interference (RNAi) approach was adopted to reduce the expression of all 3 genes at once. RNAi mutants with reduced expression of BST1-3 were unable to grow at low CO2 concentrations, exhibited a reduced affinity to inorganic carbon (Ci) compared with the wild-type cells, and showed reduced Ci uptake. We propose that these bestrophin-like proteins are essential components of the CCM that deliver HCO3- accumulated in the chloroplast stroma to CAH3 inside the thylakoid lumen.
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Affiliation(s)
- Ananya Mukherjee
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803
| | - Chun Sing Lau
- Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Charlotte E Walker
- Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Ashwani K Rai
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803
| | - Camille I Prejean
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803
| | - Gary Yates
- Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Thomas Emrich-Mills
- Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Spencer G Lemoine
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803
| | - David J Vinyard
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803
| | - Luke C M Mackinder
- Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom
| | - James V Moroney
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803;
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62
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Thylakoid localized bestrophin-like proteins are essential for the CO 2 concentrating mechanism of Chlamydomonas reinhardtii. Proc Natl Acad Sci U S A 2019; 116:16915-16920. [PMID: 31391312 PMCID: PMC6708349 DOI: 10.1073/pnas.1909706116] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Models of the CO2 concentrating mechanism (CCM) of green algae and diatoms postulate that chloroplast CO2 is generated from HCO3− brought into the acidic thylakoid lumen and converted to CO2 by specific thylakoid carbonic anhydrases. However, the identity of the transporter required for thylakoid HCO3− uptake has remained elusive. In this work, 3 bestrophin-like proteins, BST1–3, located on the thylakoid membrane have been found to be essential to the CCM of Chlamydomonas. Reduction in expression of BST1–3 markedly reduced the inorganic carbon affinity of the alga. These proteins are prime candidates to be thylakoid HCO3− transporters, a critical currently missing step of the CCM required for future engineering efforts of the Chlamydomonas CCM into plants to improve photosynthesis. The green alga Chlamydomonas reinhardtii possesses a CO2 concentrating mechanism (CCM) that helps in successful acclimation to low CO2 conditions. Current models of the CCM postulate that a series of ion transporters bring HCO3− from outside the cell to the thylakoid lumen, where the carbonic anhydrase 3 (CAH3) dehydrates accumulated HCO3− to CO2, raising the CO2 concentration for Ribulose bisphosphate carboxylase/oxygenase (Rubisco). Previously, HCO3− transporters have been identified at both the plasma membrane and the chloroplast envelope, but the transporter thought to be on the thylakoid membrane has not been identified. Three paralogous genes (BST1, BST2, and BST3) belonging to the bestrophin family have been found to be up-regulated in low CO2 conditions, and their expression is controlled by CIA5, a transcription factor that controls many CCM genes. YFP fusions demonstrate that all 3 proteins are located on the thylakoid membrane, and interactome studies indicate that they might associate with chloroplast CCM components. A single mutant defective in BST3 has near-normal growth on low CO2, indicating that the 3 bestrophin-like proteins may have redundant functions. Therefore, an RNA interference (RNAi) approach was adopted to reduce the expression of all 3 genes at once. RNAi mutants with reduced expression of BST1–3 were unable to grow at low CO2 concentrations, exhibited a reduced affinity to inorganic carbon (Ci) compared with the wild-type cells, and showed reduced Ci uptake. We propose that these bestrophin-like proteins are essential components of the CCM that deliver HCO3− accumulated in the chloroplast stroma to CAH3 inside the thylakoid lumen.
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Kaňa R, Kotabová E, Šedivá B, Kuthanová Trsková E. Photoprotective strategies in the motile cryptophyte alga Rhodomonas salina-role of non-photochemical quenching, ions, photoinhibition, and cell motility. Folia Microbiol (Praha) 2019; 64:691-703. [PMID: 31352667 DOI: 10.1007/s12223-019-00742-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 07/15/2019] [Indexed: 12/20/2022]
Abstract
We explored photoprotective strategies in a cryptophyte alga Rhodomonas salina. This cryptophytic alga represents phototrophs where chlorophyll a/c antennas in thylakoids are combined with additional light-harvesting system formed by phycobiliproteins in the chloroplast lumen. The fastest response to excessive irradiation is induction of non-photochemical quenching (NPQ). The maximal NPQ appears already after 20 s of excessive irradiation. This initial phase of NPQ is sensitive to Ca2+ channel inhibitor (diltiazem) and disappears, also, in the presence of non-actin, an ionophore for monovalent cations. The prolonged exposure to high light of R. salina cells causes photoinhibition of photosystem II (PSII) that can be further enhanced when Ca2+ fluxes are inhibited by diltiazem. The light-induced reduction in PSII photochemical activity is smaller when compared with immotile diatom Phaeodactylum tricornutum. We explain this as a result of their different photoprotective strategies. Besides the protective role of NPQ, the motile R. salina also minimizes high light exposure by increased cell velocity by almost 25% percent (25% from 82 to 104 μm/s). We suggest that motility of algal cells might have a photoprotective role at high light because algal cell rotation around longitudinal axes changes continual irradiation to periodically fluctuating light.
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Affiliation(s)
- Radek Kaňa
- Institute of Microbiology, Centre ALGATECH, Czech Academy of Sciences, Třeboň, Czech Republic.
| | - Eva Kotabová
- Institute of Microbiology, Centre ALGATECH, Czech Academy of Sciences, Třeboň, Czech Republic
| | - Barbora Šedivá
- Institute of Microbiology, Centre ALGATECH, Czech Academy of Sciences, Třeboň, Czech Republic
| | - Eliška Kuthanová Trsková
- Institute of Microbiology, Centre ALGATECH, Czech Academy of Sciences, Třeboň, Czech Republic.,Student of Faculty of Science, University of South Bohemia, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic
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Kowalewska Ł, Bykowski M, Mostowska A. Spatial organization of thylakoid network in higher plants. BOTANY LETTERS 2019. [PMID: 0 DOI: 10.1080/23818107.2019.1619195] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Affiliation(s)
- Łucja Kowalewska
- Department of Plant Anatomy and Cytology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Michał Bykowski
- Department of Plant Anatomy and Cytology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Agnieszka Mostowska
- Department of Plant Anatomy and Cytology, Faculty of Biology, University of Warsaw, Warsaw, Poland
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65
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Höhner R, Galvis VC, Strand DD, Völkner C, Krämer M, Messer M, Dinc F, Sjuts I, Bölter B, Kramer DM, Armbruster U, Kunz HH. Photosynthesis in Arabidopsis Is Unaffected by the Function of the Vacuolar K + Channel TPK3. PLANT PHYSIOLOGY 2019; 180:1322-1335. [PMID: 31053658 PMCID: PMC6752931 DOI: 10.1104/pp.19.00255] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 04/25/2019] [Indexed: 05/21/2023]
Abstract
Photosynthesis is limited by the slow relaxation of nonphotochemical quenching, which primarily dissipates excess absorbed light energy as heat. Because the heat dissipation process is proportional to light-driven thylakoid lumen acidification, manipulating thylakoid ion and proton flux via transport proteins could improve photosynthesis. However, an important aspect of the current understanding of the thylakoid ion transportome is inaccurate. Using fluorescent protein fusions, we show that the Arabidopsis (Arabidopsis thaliana) two-pore K+ channel TPK3, which had been reported to mediate thylakoid K+ flux, localizes to the tonoplast, not the thylakoid. The localization of TPK3 outside of the thylakoids is further supported by the absence of TPK3 in isolated thylakoids as well as the inability of isolated chloroplasts to import TPK3 protein. In line with the subcellular localization of TPK3 in the vacuole, we observed that photosynthesis in the Arabidopsis null mutant tpk3-1, which carries a transfer DNA insertion in the first exon, remains unaffected. To gain a comprehensive understanding of how thylakoid ion flux impacts photosynthetic efficiency under dynamic growth light regimes, we performed long-term photosynthesis imaging of established and newly isolated transthylakoid K+- and Cl--flux mutants. Our results underpin the importance of the thylakoid ion transport proteins potassium cation efflux antiporter KEA3 and voltage-dependent chloride channel VCCN1 and suggest that the activity of yet unknown K+ channel(s), but not TPK3, is critical for optimal photosynthesis in dynamic light environments.
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Affiliation(s)
- Ricarda Höhner
- Plant Physiology, School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236
| | - Viviana Correa Galvis
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, 14476 Potsdam, Germany
| | - Deserah D Strand
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, 14476 Potsdam, Germany
| | - Carsten Völkner
- Plant Physiology, School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236
| | - Moritz Krämer
- Plant Physiology, School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236
| | - Michaela Messer
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, 14476 Potsdam, Germany
| | - Firdevs Dinc
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, 14476 Potsdam, Germany
| | - Inga Sjuts
- Ludwig Maximilian University Munich, Department I, Plant Biochemistry, 82152 Planegg-Martinsried, Germany
| | - Bettina Bölter
- Ludwig Maximilian University Munich, Department I, Plant Biochemistry, 82152 Planegg-Martinsried, Germany
| | - David M Kramer
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
| | - Ute Armbruster
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, 14476 Potsdam, Germany
| | - Hans-Henning Kunz
- Plant Physiology, School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236
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66
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K + and Cl - channels/transporters independently fine-tune photosynthesis in plants. Sci Rep 2019; 9:8639. [PMID: 31201341 PMCID: PMC6570773 DOI: 10.1038/s41598-019-44972-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 05/29/2019] [Indexed: 12/14/2022] Open
Abstract
In variable light environments, plants adjust light use in photosynthetic electron transport and photoprotective dissipation in the thylakoid membrane. In this respect, roles of the K+/H+ antiporter KEA3, the Cl- channel/transporter CLCe and the voltage-dependent Cl- channel VCCN1 have been unraveled in Arabidopsis thaliana. Here we report that they independently adjust photosynthesis on the basis of analyses using single and higher order loss-of-function mutants. In short experiments of photosynthetic response on transition from dark to low light, we reveal a sequential functioning of VCCN1 and CLCe in the activation of photoprotection and of KEA3 in its downregulation to a low steady state while adjusting the electron transport. On transition from low to high light, VCCN1 accelerates the activation of photoprotection, whereas KEA3 slows it down on transition from high to low light. Based on parallel electrochromic band shift measurements, the mechanism behind is that VCCN1 builds up a pH gradient across the thylakoid membrane, whereas KEA3 dissipates this gradient, which affects photoprotection. CLCe regulates photosynthesis by a pH-independent mechanism likely involving Cl- homeostasis. Nevertheless, all genotypes grow well in alternating high and low light. Taken together, the three studied ion channels/transporters function independently in adjusting photosynthesis to the light environment.
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67
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Tanaka Y, Adachi S, Yamori W. Natural genetic variation of the photosynthetic induction response to fluctuating light environment. CURRENT OPINION IN PLANT BIOLOGY 2019; 49:52-59. [PMID: 31202005 DOI: 10.1016/j.pbi.2019.04.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 04/13/2019] [Accepted: 04/25/2019] [Indexed: 05/08/2023]
Abstract
Field-grown plants experience fluctuating light intensity for periods extending from seconds to hours because of cloud movements and self-shading. When full light intensity returns after shading, the net CO2 assimilation rate in leaves does not reach its maximum value immediately, but rises gradually over several minutes to approach a new steady state. This phenomenon has been termed photosynthetic induction, which substantially affects the efficiency of carbon fixation, and thus crop production. The significant natural variation of the speed of induction response exists among not only interspecies but also intraspecies. Recent advances in molecular analysis and high-throughput measurement techniques have revealed the genetic and eco-physiological basis of observed genetic variations in photosynthetic induction response. Here, we review the current understanding of the physiological and genetic mechanisms behind photosynthetic induction, and discusses routes to further advances.
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Affiliation(s)
- Yu Tanaka
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan; Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology, Kawaguchi, Japan.
| | - Shunsuke Adachi
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Wataru Yamori
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
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68
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Wu H, Li Z. The Importance of Cl - Exclusion and Vacuolar Cl - Sequestration: Revisiting the Role of Cl - Transport in Plant Salt Tolerance. FRONTIERS IN PLANT SCIENCE 2019; 10:1418. [PMID: 31781141 PMCID: PMC6857526 DOI: 10.3389/fpls.2019.01418] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 10/11/2019] [Indexed: 05/20/2023]
Abstract
Salinity threatens agricultural production systems across the globe. While the major focus of plant researchers working in the field of salinity stress tolerance has always been on sodium and potassium, the transport patterns and physiological roles of Cl- in plant salt stress responses are studied much less. In recent years, the role of Cl- in plant salinity stress tolerance has been revisited and has received more attention. This review attempts to address the gap in knowledge of the role of Cl- transport in plant salinity stress tolerance. Cl- transport, Cl- exclusion, vacuolar Cl- sequestration, the specificity of mechanisms employed in different plant species to control shoot Cl- accumulation, and the identity of channels and transporters involved in Cl- transport in salt stressed plants are discussed. The importance of the electrochemical gradient across the tonoplast, for vacuolar Cl- sequestration, is highlighted. The toxicity of Cl- from CaCl2 is briefly reviewed separately to that of Cl- from NaCl.
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Affiliation(s)
- Honghong Wu
- College of Plant Science & Technology, Huazhong Agricultural University, Wuhan, China
- College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
- Department of Botany and Plant Sciences, University of California, Riverside, CA, United States
- *Correspondence: Honghong Wu, ; Zhaohu Li,
| | - Zhaohu Li
- College of Plant Science & Technology, Huazhong Agricultural University, Wuhan, China
- College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
- *Correspondence: Honghong Wu, ; Zhaohu Li,
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69
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Liu J, Lu Y, Hua W, Last RL. A New Light on Photosystem II Maintenance in Oxygenic Photosynthesis. FRONTIERS IN PLANT SCIENCE 2019; 10:975. [PMID: 31417592 PMCID: PMC6685048 DOI: 10.3389/fpls.2019.00975] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 07/11/2019] [Indexed: 05/19/2023]
Abstract
Life on earth is sustained by oxygenic photosynthesis, a process that converts solar energy, carbon dioxide, and water into chemical energy and biomass. Sunlight is essential for growth and productivity of photosynthetic organisms. However, exposure to an excessive amount of light adversely affects fitness due to photooxidative damage to the photosynthetic machinery, primarily to the reaction center of the oxygen-evolving photosystem II (PSII). Photosynthetic organisms have evolved diverse photoprotective and adaptive strategies to avoid, alleviate, and repair PSII damage caused by high-irradiance or fluctuating light. Rapid and harmless dissipation of excess absorbed light within antenna as heat, which is measured by chlorophyll fluorescence as non-photochemical quenching (NPQ), constitutes one of the most efficient protective strategies. In parallel, an elaborate repair system represents another efficient strategy to maintain PSII reaction centers in active states. This article reviews both the reaction center-based strategy for robust repair of photodamaged PSII and the antenna-based strategy for swift control of PSII light-harvesting (NPQ). We discuss evolutionarily and mechanistically diverse strategies used by photosynthetic organisms to maintain PSII function for growth and productivity under static high-irradiance light or fluctuating light environments. Knowledge of mechanisms underlying PSII maintenance would facilitate bioengineering photosynthesis to enhance agricultural productivity and sustainability to feed a growing world population amidst climate change.
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Affiliation(s)
- Jun Liu
- Department of Functional Genomics and Molecular Biology, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
- *Correspondence: Jun Liu,
| | - Yan Lu
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, United States
| | - Wei Hua
- Department of Functional Genomics and Molecular Biology, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
- Wei Hua
| | - Robert L. Last
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
- Department of Plant Biology, Michigan State University, East Lansing, MI, United States
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Shimadzu S, Seo M, Terashima I, Yamori W. Whole Irradiated Plant Leaves Showed Faster Photosynthetic Induction Than Individually Irradiated Leaves via Improved Stomatal Opening. FRONTIERS IN PLANT SCIENCE 2019; 10:1512. [PMID: 31850018 PMCID: PMC6892984 DOI: 10.3389/fpls.2019.01512] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Accepted: 10/31/2019] [Indexed: 05/03/2023]
Abstract
Rapid photosynthetic induction is crucial for plants under fluctuating light conditions in a crop canopy as well as in an understory. Most previous studies have focused on photosynthetic induction responses in a single leaf, whereas the systemic responses of the whole plant have not been considered. In a natural environment, however, both single leaves and whole plants are exposed to sunlight, since the light environment is not uniform even within a given plant. In the present study, we examined whether there is any difference between the photosynthetic induction response of a leaf of a whole irradiated plant and an individually irradiated leaf in Arabidopsis thaliana to consider photosynthetic induction as the response of a whole plant. We used two methods, the visualization of photosynthesis and direct measurements of gas-exchange and Chl fluorescence, to demonstrate that whole irradiated plant promoted its photosynthetic induction via improved stomatal opening compared with individually irradiated leaf. Furthermore, using two Arabidopsis knockout mutants of abscisic acid transporter, abcg25 and abcg40, the present study suggests that abscisic acid could be involved in this systemic response for stomatal opening, allowing plants to optimize the use of light energy at minimal cost in plants in a dynamic light environment.
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Affiliation(s)
- Shunji Shimadzu
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Mitsunori Seo
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Ichiro Terashima
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Wataru Yamori
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
- Institute for Sustainable Agro-Ecosystem Services, The University of Tokyo, Nishitokyo, Japan
- *Correspondence: Wataru Yamori,
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71
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Schneider D, Lopez LS, Li M, Crawford JD, Kirchhoff H, Kunz HH. Fluctuating light experiments and semi-automated plant phenotyping enabled by self-built growth racks and simple upgrades to the IMAGING-PAM. PLANT METHODS 2019; 15:156. [PMID: 31889980 PMCID: PMC6927185 DOI: 10.1186/s13007-019-0546-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 12/09/2019] [Indexed: 05/06/2023]
Abstract
BACKGROUND Over the last years, several plant science labs have started to employ fluctuating growth light conditions to simulate natural light regimes more closely. Many plant mutants reveal quantifiable effects under fluctuating light despite being indistinguishable from wild-type plants under standard constant light. Moreover, many subtle plant phenotypes become intensified and thus can be studied in more detail. This observation has caused a paradigm shift within the photosynthesis research community and an increasing number of scientists are interested in using fluctuating light growth conditions. However, high installation costs for commercial controllable LED setups as well as costly phenotyping equipment can make it hard for small academic groups to compete in this emerging field. RESULTS We show a simple do-it-yourself approach to enable fluctuating light growth experiments. Our results using previously published fluctuating light sensitive mutants, stn7 and pgr5, confirm that our low-cost setup yields similar results as top-prized commercial growth regimes. Moreover, we show how we increased the throughput of our Walz IMAGING-PAM, also found in many other departments around the world. We have designed a Python and R-based open source toolkit that allows for semi-automated sample segmentation and data analysis thereby reducing the processing bottleneck of large experimental datasets. We provide detailed instructions on how to build and functionally test each setup. CONCLUSIONS With material costs well below USD$1000, it is possible to setup a fluctuating light rack including a constant light control shelf for comparison. This allows more scientists to perform experiments closer to natural light conditions and contribute to an emerging research field. A small addition to the IMAGING-PAM hardware not only increases sample throughput but also enables larger-scale plant phenotyping with automated data analysis.
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Affiliation(s)
- Dominik Schneider
- Compact Plants Phenomics Center, Washington State University, PO Box 646340, Pullman, WA 99164-6340 USA
- Institute of Biological Chemistry, Washington State University, PO Box 646340, Pullman, WA 99164-6340 USA
| | - Laura S. Lopez
- Plant Physiology, School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA 99164-4236 USA
| | - Meng Li
- Institute of Biological Chemistry, Washington State University, PO Box 646340, Pullman, WA 99164-6340 USA
| | - Joseph D. Crawford
- Plant Physiology, School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA 99164-4236 USA
| | - Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, PO Box 646340, Pullman, WA 99164-6340 USA
| | - Hans-Henning Kunz
- Plant Physiology, School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA 99164-4236 USA
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Davis GA, Kramer DM. Optimization of ATP Synthase c-Rings for Oxygenic Photosynthesis. FRONTIERS IN PLANT SCIENCE 2019; 10:1778. [PMID: 32082344 PMCID: PMC7003800 DOI: 10.3389/fpls.2019.01778] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/20/2019] [Indexed: 05/10/2023]
Abstract
The conversion of sunlight into useable cellular energy occurs via the proton-coupled electron transfer reactions of photosynthesis. Light is absorbed by photosynthetic pigments and transferred to photochemical reaction centers to initiate electron and proton transfer reactions to store energy in a redox gradient and an electrochemical proton gradient (proton motive force, pmf), composed of a concentration gradient (ΔpH) and an electric field (Δψ), which drives the synthesis of ATP through the thylakoid FoF1-ATP synthase. Although ATP synthase structure and function are conserved across biological kingdoms, the number of membrane-embedded ion-binding c subunits varies between organisms, ranging from 8 to 17, theoretically altering the H+/ATP ratio for different ATP synthase complexes, with profound implications for the bioenergetic processes of cellular metabolism. Of the known c-ring stoichiometries, photosynthetic c-rings are among the largest identified stoichiometries, and it has been proposed that decreasing the c-stoichiometry could increase the energy conversion efficiency of photosynthesis. Indeed, there is strong evidence that the high H+/ATP of the chloroplast ATP synthase results in a low ATP/nicotinamide adenine dinucleotide phosphate (NADPH) ratio produced by photosynthetic linear electron flow, requiring secondary processes such as cyclic electron flow to support downstream metabolism. We hypothesize that the larger c subunit stoichiometry observed in photosynthetic ATP synthases was selected for because it allows the thylakoid to maintain pmf in a range where ATP synthesis is supported, but avoids excess Δψ and ΔpH, both of which can lead to production of reactive oxygen species and subsequent photodamage. Numerical kinetic simulations of the energetics of chloroplast photosynthetic reactions with altered c-ring size predicts the energy storage of pmf and its effects on the photochemical reaction centers strongly support this hypothesis, suggesting that, despite the low efficiency and suboptimal ATP/NADPH ratio, a high H+/ATP is favored to avoid photodamage. This has important implications for the evolution and regulation of photosynthesis as well as for synthetic biology efforts to alter photosynthetic efficiency by engineering the ATP synthase.
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Affiliation(s)
- Geoffry A. Davis
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
| | - David M. Kramer
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
- *Correspondence: David M. Kramer,
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Global spectroscopic analysis to study the regulation of the photosynthetic proton motive force: A critical reappraisal. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:676-683. [DOI: 10.1016/j.bbabio.2018.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 06/03/2018] [Accepted: 07/02/2018] [Indexed: 01/11/2023]
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74
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Huang W, Cai YF, Wang JH, Zhang SB. Chloroplastic ATP synthase plays an important role in the regulation of proton motive force in fluctuating light. JOURNAL OF PLANT PHYSIOLOGY 2018; 226:40-47. [PMID: 29698911 DOI: 10.1016/j.jplph.2018.03.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 03/25/2018] [Accepted: 03/26/2018] [Indexed: 06/08/2023]
Abstract
The proton motive force (pmf) across the thylakoid membranes plays a key role for photosynthesis in fluctuating light. However, the mechanisms underlying the regulation of pmf in fluctuating light are not well known. In this study, we aimed to identify the roles of chloroplastic ATP synthase and cyclic electron flow (CEF) around photosystem I (PSI) in the regulation of the pmf in fluctuating light. To do this, we measured chlorophyll fluorescence, P700 parameters, and the electrochromic shift signal in the fluctuating light alternating between 918 (high light) and 89 (low light) μmol photons m-2 s-1 every 5 min. We found that the activity of chloroplastic ATP synthase (gH+), pmf, CEF activity, non-photochemical quenching (NPQ), and the P700 redox state changed rapidly in fluctuating light. During transition from low to high light, the decreased gH+ and the stimulation of CEF both contributed to the rapid formation of pmf, activating NPQ and optimizing the redox state of P700 in PSI. During the low-light phases, gH+ rapidly increased and the pmf declined sharply, leading to the relaxation of NPQ and down-regulation of photosynthetic control. These findings indicate that in fluctuating light the gH+ and CEF are finely regulated to modulate the pmf formation, avoiding the over-accumulation of reactive intermediates and maximizing energy use efficiency.
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Affiliation(s)
- Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - Yan-Fei Cai
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, Kunming, Yunnan, China
| | - Ji-Hua Wang
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, Kunming, Yunnan, China.
| | - Shi-Bao Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China.
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75
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Marchand J, Heydarizadeh P, Schoefs B, Spetea C. Ion and metabolite transport in the chloroplast of algae: lessons from land plants. Cell Mol Life Sci 2018; 75:2153-2176. [PMID: 29541792 PMCID: PMC5948301 DOI: 10.1007/s00018-018-2793-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 03/01/2018] [Accepted: 03/07/2018] [Indexed: 12/28/2022]
Abstract
Chloroplasts are endosymbiotic organelles and play crucial roles in energy supply and metabolism of eukaryotic photosynthetic organisms (algae and land plants). They harbor channels and transporters in the envelope and thylakoid membranes, mediating the exchange of ions and metabolites with the cytosol and the chloroplast stroma and between the different chloroplast subcompartments. In secondarily evolved algae, three or four envelope membranes surround the chloroplast, making more complex the exchange of ions and metabolites. Despite the importance of transport proteins for the optimal functioning of the chloroplast in algae, and that many land plant homologues have been predicted, experimental evidence and molecular characterization are missing in most cases. Here, we provide an overview of the current knowledge about ion and metabolite transport in the chloroplast from algae. The main aspects reviewed are localization and activity of the transport proteins from algae and/or of homologues from other organisms including land plants. Most chloroplast transporters were identified in the green alga Chlamydomonas reinhardtii, reside in the envelope and participate in carbon acquisition and metabolism. Only a few identified algal transporters are located in the thylakoid membrane and play role in ion transport. The presence of genes for putative transporters in green algae, red algae, diatoms, glaucophytes and cryptophytes is discussed, and roles in the chloroplast are suggested. A deep knowledge in this field is required because algae represent a potential source of biomass and valuable metabolites for industry, medicine and agriculture.
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Affiliation(s)
- Justine Marchand
- Metabolism, Bioengineering of Microalgal Molecules and Applications (MIMMA), Mer Molécules Santé, IUML, FR 3473 CNRS, Le Mans University, 72000, Le Mans, France
| | - Parisa Heydarizadeh
- Metabolism, Bioengineering of Microalgal Molecules and Applications (MIMMA), Mer Molécules Santé, IUML, FR 3473 CNRS, Le Mans University, 72000, Le Mans, France
| | - Benoît Schoefs
- Metabolism, Bioengineering of Microalgal Molecules and Applications (MIMMA), Mer Molécules Santé, IUML, FR 3473 CNRS, Le Mans University, 72000, Le Mans, France.
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, 40530, Göteborg, Sweden.
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76
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Geilfus CM. Chloride: from Nutrient to Toxicant. PLANT & CELL PHYSIOLOGY 2018; 59:877-886. [PMID: 29660029 DOI: 10.1093/pcp/pcy071] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 03/05/2018] [Indexed: 05/25/2023]
Abstract
In salinized soils in which chloride (Cl-) is the dominant salt anion, growth of plants that tolerate only low concentrations of salt (glycophytes) is disturbed by Cl- toxicity. Chlorotic discolorations precede necrotic lesions, causing yield reductions. Little is known about the effects of Cl- toxicity on these dysfunctions. A lack of understanding exists regarding (i) the molecular and physiological mechanisms that lead to Cl--induced damage and (ii) the adaptive aspects of induced tolerance to Cl- salinity. Here, mechanistic explanations for the Cl--induced stress responses are proposed and novel ideas and strategies by which glycophytic plants avoid the excessive accumulation of Cl- are reviewed. New experiments are suggested to test the proposed hypotheses. Cl- salinity constrains global food security and thus we urgently need more research into the causes and consequences of Cl- salinity.
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Affiliation(s)
- Christoph-Martin Geilfus
- Controlled Environment Horticulture, Faculty of Life Sciences, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-University of Berlin, Albrecht-Thaer-Weg 1, D-14195 Berlin, Germany
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77
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Demidchik V. ROS-Activated Ion Channels in Plants: Biophysical Characteristics, Physiological Functions and Molecular Nature. Int J Mol Sci 2018; 19:E1263. [PMID: 29690632 PMCID: PMC5979493 DOI: 10.3390/ijms19041263] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 04/02/2018] [Accepted: 04/03/2018] [Indexed: 12/16/2022] Open
Abstract
Ion channels activated by reactive oxygen species (ROS) have been found in the plasma membrane of charophyte Nitella flixilis, dicotyledon Arabidopsis thaliana, Pyrus pyrifolia and Pisum sativum, and the monocotyledon Lilium longiflorum. Their activities have been reported in charophyte giant internodes, root trichoblasts and atrichoblasts, pollen tubes, and guard cells. Hydrogen peroxide and hydroxyl radicals are major activating species for these channels. Plant ROS-activated ion channels include inwardly-rectifying, outwardly-rectifying, and voltage-independent groups. The inwardly-rectifying ROS-activated ion channels mediate Ca2+-influx for growth and development in roots and pollen tubes. The outwardly-rectifying group facilitates K⁺ efflux for the regulation of osmotic pressure in guard cells, induction of programmed cell death, and autophagy in roots. The voltage-independent group mediates both Ca2+ influx and K⁺ efflux. Most studies suggest that ROS-activated channels are non-selective cation channels. Single-channel studies revealed activation of 14.5-pS Ca2+ influx and 16-pS K⁺ efflux unitary conductances in response to ROS. The molecular nature of ROS-activated Ca2+ influx channels remains poorly understood, although annexins and cyclic nucleotide-gated channels have been proposed for this role. The ROS-activated K⁺ channels have recently been identified as products of Stellar K⁺ Outward Rectifier (SKOR) and Guard cell Outwardly Rectifying K⁺ channel (GORK) genes.
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Affiliation(s)
- Vadim Demidchik
- Department of Horticulture, School of Food Science and Engineering, Foshan University, Foshan 528000, China.
- Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Avenue, 220030 Minsk, Belarus.
- Russian Academy of Sciences, Komarov Botanical Institute, 2 Professora Popova Street, 197376 St. Petersburg, Russia.
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78
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Davis GA, Rutherford AW, Kramer DM. Hacking the thylakoid proton motive force for improved photosynthesis: modulating ion flux rates that control proton motive force partitioning into Δ ψ and ΔpH. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0381. [PMID: 28808100 DOI: 10.1098/rstb.2016.0381] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/31/2017] [Indexed: 11/12/2022] Open
Abstract
There is considerable interest in improving plant productivity by altering the dynamic responses of photosynthesis in tune with natural conditions. This is exemplified by the 'energy-dependent' form of non-photochemical quenching (qE), the formation and decay of which can be considerably slower than natural light fluctuations, limiting photochemical yield. In addition, we recently reported that rapidly fluctuating light can produce field recombination-induced photodamage (FRIP), where large spikes in electric field across the thylakoid membrane (Δψ) induce photosystem II recombination reactions that produce damaging singlet oxygen (1O2). Both qE and FRIP are directly linked to the thylakoid proton motive force (pmf), and in particular, the slow kinetics of partitioning pmf into its ΔpH and Δψ components. Using a series of computational simulations, we explored the possibility of 'hacking' pmf partitioning as a target for improving photosynthesis. Under a range of illumination conditions, increasing the rate of counter-ion fluxes across the thylakoid membrane should lead to more rapid dissipation of Δψ and formation of ΔpH. This would result in increased rates for the formation and decay of qE while resulting in a more rapid decline in the amplitudes of Δψ-spikes and decreasing 1O2 production. These results suggest that ion fluxes may be a viable target for plant breeding or engineering. However, these changes also induce transient, but substantial mismatches in the ATP : NADPH output ratio as well as in the osmotic balance between the lumen and stroma, either of which may explain why evolution has not already accelerated thylakoid ion fluxes. Overall, though the model is simplified, it recapitulates many of the responses seen in vivo, while spotlighting critical aspects of the complex interactions between pmf components and photosynthetic processes. By making the programme available, we hope to enable the community of photosynthesis researchers to further explore and test specific hypotheses.This article is part of the themed issue 'Enhancing photosynthesis in crop plants: targets for improvement'.
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Affiliation(s)
- Geoffry A Davis
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA.,Cell and Molecular Biology Graduate Program, Michigan State University, East Lansing, MI 48824, USA
| | | | - David M Kramer
- Department of Energy 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
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79
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Dahal K, Vanlerberghe GC. Improved chloroplast energy balance during water deficit enhances plant growth: more crop per drop. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1183-1197. [PMID: 29281082 PMCID: PMC6018952 DOI: 10.1093/jxb/erx474] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 12/07/2017] [Indexed: 05/02/2023]
Abstract
The non-energy-conserving alternative oxidase (AOX) respiration of plant mitochondria is known to interact with chloroplast photosynthesis. This may have consequences for growth, particularly under sub-optimal conditions when energy imbalances can impede photosynthesis. This hypothesis was tested by comparing the metabolism and growth of wild-type Nicotiana tabacum with that of AOX knockdown and overexpression lines during a prolonged steady-state mild to moderate water deficit. Under moderate water deficit, the AOX amount was an important determinant of the rate of both mitochondrial respiration in the light and net photosynthetic CO2 assimilation (A) at the growth irradiance. In particular, AOX respiration was necessary to maintain optimal proton and electron fluxes at the chloroplast thylakoid membrane, which in turn prevented a water-deficit-induced biochemical limitation of photosynthesis. As a result of differences in A, AOX overexpressors gained more biomass and knockdowns gained less biomass than wild-type during moderate water deficit. Biomass partitioning also differed, with the overexpressors having a higher percentage, and the knockdowns having a lower percentage, of total above-ground biomass in reproductive tissue than wild-type. The results establish that improving chloroplast energy balance by using a non-energy-conserving respiratory electron sink can increase photosynthesis and growth during prolonged water deficit.
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Affiliation(s)
- Keshav Dahal
- Department of Biological Sciences and Department of Cell and Systems Biology, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Greg C Vanlerberghe
- Department of Biological Sciences and Department of Cell and Systems Biology, University of Toronto Scarborough, Toronto, Ontario, Canada
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80
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Ruiz-Lau N, Sáez Á, Lanza M, Benito B. Genomic and Transcriptomic Compilation of Chloroplast Ionic Transporters of Physcomitrella patens. Study of NHAD Transporters in Na+ and K+ Homeostasis. PLANT & CELL PHYSIOLOGY 2017; 58:2166-2178. [PMID: 29036645 DOI: 10.1093/pcp/pcx150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 09/26/2017] [Indexed: 06/07/2023]
Abstract
K+ is widely used by plant cells, whereas Na+ can easily reach toxic levels during plant growth, which typically occurs in saline environments; however, the effects and functions in the chloroplast have been only roughly estimated. Traditionally, the occurrence of ionic fluxes across the chloroplast envelope or the thylakoid membranes has been mostly deduced from physiological measurements or from knowledge of chloroplast metabolism. However, many of the proteins involved in these fluxes have not yet been characterized. Based on genomic and RNA sequencing (RNA-seq) analyses, we present a comprehensive compilation of genes encoding putative ion transporters and channels expressed in the chloroplasts of the moss Physcomitrella patens, with a special emphasis on those related to Na+ and K+ fluxes. Based on the functional characterization of nhad mutants, we also discuss the putative role of NHAD transporters in Na+ homeostasis and osmoregulation of this organelle and the putative contribution of chloroplasts to salt tolerance in this moss. We demonstrate that NaCl does not affect the chloroplast functionality in Physcomitrella despite significantly modifying expression of ionic transporters and cellular morphology, specifically the chloroplast ultrastructure, revealing a high starch accumulation. Additionally, NHAD transporters apparently do not play any essential roles in salt tolerance.
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Affiliation(s)
- Nancy Ruiz-Lau
- CONACYT-Instituto Tecnológico de Tuxtla Gutiérrez, Carretera Panamericana Km 1080, Terán 29050, Tuxtla Gutiérrez, Chis, México
| | - Ángela Sáez
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus Montegancedo UPM, 28223-Pozuelo de Alarcón (Madrid), Spain
| | - Mónica Lanza
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus Montegancedo UPM, 28223-Pozuelo de Alarcón (Madrid), Spain
| | - Begoña Benito
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus Montegancedo UPM, 28223-Pozuelo de Alarcón (Madrid), Spain
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81
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Kawashima R, Sato R, Harada K, Masuda S. Relative contributions of PGR5- and NDH-dependent photosystem I cyclic electron flow in the generation of a proton gradient in Arabidopsis chloroplasts. PLANTA 2017; 246:1045-1050. [PMID: 28828567 DOI: 10.1007/s00425-017-2761-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 08/15/2017] [Indexed: 05/11/2023]
Abstract
Respective contributions of PGR5- and NDH-dependent cyclic electron flows around photosystem I for generating the proton gradient across the thylakoid membrane are ~30 and ~5%. The proton concentration gradient across the thylakoid membrane (ΔpH) produced by photosynthetic electron transport is the driving force of ATP synthesis and non-photochemical quenching. Two types of electron transfer contribute to ΔpH formation: linear electron flow (LEF) and cyclic electron flow (CEF, divided into PGR5- and NDH-dependent pathways). However, the respective contributions of LEF and CEF to ΔpH formation are largely unknown. We employed fluorescence quenching analysis with the pH indicator 9-aminoacridine to directly monitor ΔpH formation in isolated chloroplasts of Arabidopsis mutants lacking PGR5- and/or NDH-dependent CEF. The results indicate that ΔpH formation is mostly due to LEF, with the contributions of PGR5- and NDH-dependent CEF estimated as only ~30 and ~5%, respectively.
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Affiliation(s)
- Rinya Kawashima
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan
| | - Ryoichi Sato
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan
- Division of Environmental Photobiology, National Institute for Basic Biology, Okazaki, 444-8585, Japan
| | - Kyohei Harada
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan
| | - Shinji Masuda
- Center for Biological Resources and Informatics, Tokyo Institute of Technology, Yokohama, Japan.
- Earth-life Science Institute, Tokyo Institute of Technology, Tokyo, Japan.
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82
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Hedrich R, Geiger D. Biology of SLAC1-type anion channels - from nutrient uptake to stomatal closure. THE NEW PHYTOLOGIST 2017; 216:46-61. [PMID: 28722226 DOI: 10.1111/nph.14685] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 04/25/2017] [Indexed: 05/22/2023]
Abstract
Contents 46 I. 46 II. 47 III. 50 IV. 53 V. 56 VI. 57 58 58 References 58 SUMMARY: Stomatal guard cells control leaf CO2 intake and concomitant water loss to the atmosphere. When photosynthetic CO2 assimilation is limited and the ratio of CO2 intake to transpiration becomes suboptimal, guard cells, sensing the rise in CO2 concentration in the substomatal cavity, deflate and the stomata close. Screens for mutants that do not close in response to experimentally imposed high CO2 atmospheres identified the guard cell-expressed Slowly activating anion channel, SLAC1, as the key player in the regulation of stomatal closure. SLAC1 evolved, though, before the emergence of guard cells. In Arabidopsis, SLAC1 is the founder member of a family of anion channels, which comprises four homologues. SLAC1 and SLAH3 mediate chloride and nitrate transport in guard cells, while SLAH1, SLAH2 and SLAH3 are engaged in root nitrate and chloride acquisition, and anion translocation to the shoot. The signal transduction pathways involved in CO2 , water stress and nutrient-sensing activate SLAC/SLAH via distinct protein kinase/phosphatase pairs. In this review, we discuss the role that SLAC/SLAH channels play in guard cell closure, on the one hand, and in the root-shoot continuum on the other, along with the molecular basis of the channels' anion selectivity and gating.
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Affiliation(s)
- Rainer Hedrich
- Institute for Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, Biocenter, University of Wuerzburg, Wuerzburg, 97082, Germany
| | - Dietmar Geiger
- Institute for Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, Biocenter, University of Wuerzburg, Wuerzburg, 97082, Germany
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83
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Sato R, Kono M, Harada K, Ohta H, Takaichi S, Masuda S. FLUCTUATING-LIGHT-ACCLIMATION PROTEIN1, Conserved in Oxygenic Phototrophs, Regulates H+ Homeostasis and Non-Photochemical Quenching in Chloroplasts. PLANT & CELL PHYSIOLOGY 2017; 58:1622-1630. [PMID: 29016945 DOI: 10.1093/pcp/pcx110] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 07/31/2017] [Indexed: 05/21/2023]
Abstract
Plants have mechanisms allowing them to acclimate to intense light conditions, which involves the dissipation of excess light energy. These mechanisms allow plants to perform photosynthesis efficiently and, therefore, must be accurately and precisely controlled. However, how plants dissipate excess light energy has yet to be fully elucidated. Herein we report the identification of a gene, which we named Fluctuating-Light-Acclimation Protein1 (FLAP1), that is conserved in oxygenic phototrophs. We show that Arabidopsis FLAP1 is associated with chloroplast thylakoid and envelope membranes and that the flap1 mutant shows delayed non-photochemical quenching (NPQ) relaxation during induction of photosynthesis at moderate light intensity. Under fluctuating light conditions, NPQ levels in the flap1 mutant were higher than those in the wild type during the high light period, and the mutant exhibited a pale-green phenotype. These findings suggest that FLAP1 is involved in NPQ control, which is important for an acclimation response to fluctuating light.
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Affiliation(s)
- Ryoichi Sato
- Graduate School of Bioscience & Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Masaru Kono
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - Kyohei Harada
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Hiroyuki Ohta
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8551, Japan
| | | | - Shinji Masuda
- Center for Biological Resources & Informatics, Tokyo Institute of Technology, Yokohama 226-8501, Japan
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8551, Japan
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84
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A chloroplast thylakoid lumen protein is required for proper photosynthetic acclimation of plants under fluctuating light environments. Proc Natl Acad Sci U S A 2017; 114:E8110-E8117. [PMID: 28874535 DOI: 10.1073/pnas.1712206114] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Despite our increasingly sophisticated understanding of mechanisms ensuring efficient photosynthesis under laboratory-controlled light conditions, less is known about the regulation of photosynthesis under fluctuating light. This is important because-in nature-photosynthetic organisms experience rapid and extreme changes in sunlight, potentially causing deleterious effects on photosynthetic efficiency and productivity. Here we report that the chloroplast thylakoid lumenal protein MAINTENANCE OF PHOTOSYSTEM II UNDER HIGH LIGHT 2 (MPH2; encoded by At4g02530) is required for growth acclimation of Arabidopsis thaliana plants under controlled photoinhibitory light and fluctuating light environments. Evidence is presented that mph2 mutant light stress susceptibility results from a defect in photosystem II (PSII) repair, and our results are consistent with the hypothesis that MPH2 is involved in disassembling monomeric complexes during regeneration of dimeric functional PSII supercomplexes. Moreover, mph2-and previously characterized PSII repair-defective mutants-exhibited reduced growth under fluctuating light conditions, while PSII photoprotection-impaired mutants did not. These findings suggest that repair is not only required for PSII maintenance under static high-irradiance light conditions but is also a regulatory mechanism facilitating photosynthetic adaptation under fluctuating light environments. This work has implications for improvement of agricultural plant productivity through engineering PSII repair.
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85
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Spetea C, Herdean A, Allorent G, Carraretto L, Finazzi G, Szabo I. An update on the regulation of photosynthesis by thylakoid ion channels and transporters in Arabidopsis. PHYSIOLOGIA PLANTARUM 2017; 161:16-27. [PMID: 28332210 DOI: 10.1111/ppl.12568] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 02/08/2017] [Accepted: 02/20/2017] [Indexed: 05/07/2023]
Abstract
In natural, variable environments, plants rapidly adjust photosynthesis for optimal balance between light absorption and utilization. There is increasing evidence suggesting that ion fluxes across the chloroplast thylakoid membrane play an important role in this regulation by affecting the proton motive force and consequently photosynthesis and thylakoid membrane ultrastructure. This article presents an update on the thylakoid ion channels and transporters characterized in Arabidopsis thaliana as being involved in these processes, as well as an outlook at the evolutionary conservation of their functions in other photosynthetic organisms. This is a contribution to shed light on the thylakoid network of ion fluxes and how they help plants to adjust photosynthesis in variable light environments.
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Affiliation(s)
- Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, 40530, Sweden
| | - Andrei Herdean
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, 40530, Sweden
| | - Guillaume Allorent
- Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, Centre National de la Recherche Scientifique (CNRS), Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Institut National Recherche Agronomique (INRA), Institut de Biosciences et Biotechnologie de Grenoble (BIG), Université Grenoble Alpes (UGA), Grenoble, 38100, France
| | - Luca Carraretto
- Department of Biology, University of Padova, Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy
| | - Giovanni Finazzi
- Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, Centre National de la Recherche Scientifique (CNRS), Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Institut National Recherche Agronomique (INRA), Institut de Biosciences et Biotechnologie de Grenoble (BIG), Université Grenoble Alpes (UGA), Grenoble, 38100, France
| | - Ildikò Szabo
- Department of Biology, University of Padova, Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy
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86
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Takagi D, Amako K, Hashiguchi M, Fukaki H, Ishizaki K, Goh T, Fukao Y, Sano R, Kurata T, Demura T, Sawa S, Miyake C. Chloroplastic ATP synthase builds up a proton motive force preventing production of reactive oxygen species in photosystem I. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 91:306-324. [PMID: 28380278 DOI: 10.1111/tpj.13566] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 03/29/2017] [Accepted: 04/03/2017] [Indexed: 05/19/2023]
Abstract
Over-reduction of the photosynthetic electron transport (PET) chain should be avoided, because the accumulation of reducing electron carriers produces reactive oxygen species (ROS) within photosystem I (PSI) in thylakoid membranes and causes oxidative damage to chloroplasts. To prevent production of ROS in thylakoid membranes the H+ gradient (ΔpH) needs to be built up across the thylakoid membranes to suppress the over-reduction state of the PET chain. In this study, we aimed to identify the critical component that stimulates ΔpH formation under illumination in higher plants. To do this, we screened ethyl methane sulfonate (EMS)-treated Arabidopsis thaliana, in which the formation of ΔpH is impaired and the PET chain caused over-reduction under illumination. Subsequently, we isolated an allelic mutant that carries a missense mutation in the γ-subunit of chloroplastic CF0 CF1 -ATP synthase, named hope2. We found that hope2 suppressed the formation of ΔpH during photosynthesis because of the high H+ efflux activity from the lumenal to stromal side of the thylakoid membranes via CF0 CF1 -ATP synthase. Furthermore, PSI was in a more reduced state in hope2 than in wild-type (WT) plants, and hope2 was more vulnerable to PSI photoinhibition than WT under illumination. These results suggested that chloroplastic CF0 CF1 -ATP synthase adjusts the redox state of the PET chain, especially for PSI, by modulating H+ efflux activity across the thylakoid membranes. Our findings suggest the importance of the buildup of ΔpH depending on CF0 CF1 -ATP synthase to adjust the redox state of the reaction center chlorophyll P700 in PSI and to suppress the production of ROS in PSI during photosynthesis.
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Affiliation(s)
- Daisuke Takagi
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
- Core Research for Environmental Science and Technology, Japan Science and Technology Agency, 7 Gobancho, Chiyoda-ku, Tokyo, 102-0076, Japan
| | - Katsumi Amako
- Faculty of Nutrition, Kobe Gakuin University, Kobe, 651-2180, Japan
| | - Masaki Hashiguchi
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
| | - Hidehiro Fukaki
- Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501, Japan
| | - Kimitsune Ishizaki
- Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501, Japan
| | - Tatsuaki Goh
- Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501, Japan
| | - Yoichiro Fukao
- Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, 630-0192, Japan
| | - Ryosuke Sano
- Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, 630-0192, Japan
| | - Tetsuya Kurata
- Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, 630-0192, Japan
- Graduate School of Life Sciences, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, 980-8578, Japan
| | - Taku Demura
- Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, 630-0192, Japan
| | - Shinichiro Sawa
- Graduate School of Science and Technology, Kumamoto University, Kurokami, Tyuou-ku, Kumamoto, 860-8555, Japan
| | - Chikahiro Miyake
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
- Core Research for Environmental Science and Technology, Japan Science and Technology Agency, 7 Gobancho, Chiyoda-ku, Tokyo, 102-0076, Japan
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87
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Szabò I, Spetea C. Impact of the ion transportome of chloroplasts on the optimization of photosynthesis. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3115-3128. [PMID: 28338935 DOI: 10.1093/jxb/erx063] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Ions play fundamental roles in all living cells, and their gradients are often essential to fuel transport, regulate enzyme activities, and transduce energy within cells. Regulation of their homeostasis is essential for cell metabolism. Recent results indicate that modulation of ion fluxes might also represent a useful strategy to regulate one of the most important physiological processes taking place in chloroplasts, photosynthesis. Photosynthesis is highly regulated, due to its unique role as a cellular engine for growth in the light. Controlling the balance between ATP and NADPH synthesis is a critical task, and availability of these molecules can limit the overall photosynthetic yield. Photosynthetic organisms optimize photosynthesis in low light, where excitation energy limits CO2 fixation, and minimize photo-oxidative damage in high light by dissipating excess photons. Despite extensive studies of these phenomena, the mechanism governing light utilization in plants is still poorly understood. In this review, we provide an update of the recently identified chloroplast-located ion channels and transporters whose function impacts photosynthetic efficiency in plants.
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Affiliation(s)
- Ildikò Szabò
- Department of Biology, University of Padova, Italy; CNR Institute of Neuroscience, Padova, Italy
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, 40530 Gothenburg, Sweden
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88
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Bose J, Munns R, Shabala S, Gilliham M, Pogson B, Tyerman SD. Chloroplast function and ion regulation in plants growing on saline soils: lessons from halophytes. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3129-3143. [PMID: 28472512 DOI: 10.1093/jxb/erx142] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Salt stress impacts multiple aspects of plant metabolism and physiology. For instance it inhibits photosynthesis through stomatal limitation, causes excessive accumulation of sodium and chloride in chloroplasts, and disturbs chloroplast potassium homeostasis. Most research on salt stress has focused primarily on cytosolic ion homeostasis with few studies of how salt stress affects chloroplast ion homeostasis. This review asks the question whether membrane-transport processes and ionic relations are differentially regulated between glycophyte and halophyte chloroplasts and whether this contributes to the superior salt tolerance of halophytes. The available literature indicates that halophytes can overcome stomatal limitation by switching to CO2 concentrating mechanisms and increasing the number of chloroplasts per cell under saline conditions. Furthermore, salt entry into the chloroplast stroma may be critical for grana formation and photosystem II activity in halophytes but not in glycophytes. Salt also inhibits some stromal enzymes (e.g. fructose-1,6-bisphosphatase) to a lesser extent in halophyte species. Halophytes accumulate more chloride in chloroplasts than glycophytes and appear to use sodium in functional roles. We propose the molecular identities of candidate transporters that move sodium, chloride and potassium across chloroplast membranes and discuss how their operation may regulate photochemistry and photosystem I and II activity in chloroplasts.
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Affiliation(s)
- Jayakumar Bose
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia
| | - Rana Munns
- Australian Research Council Centre of Excellence in Plant Energy Biology, and School of Agriculture and Environment, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Sergey Shabala
- School of Land and Food, University of Tasmania, Private Bag 54, Hobart, TAS 7001, Australia
| | - Matthew Gilliham
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia
| | - Barry Pogson
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Stephen D Tyerman
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia
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89
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Armbruster U, Correa Galvis V, Kunz HH, Strand DD. The regulation of the chloroplast proton motive force plays a key role for photosynthesis in fluctuating light. CURRENT OPINION IN PLANT BIOLOGY 2017; 37:56-62. [PMID: 28426975 DOI: 10.1016/j.pbi.2017.03.012] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/23/2017] [Accepted: 03/24/2017] [Indexed: 05/22/2023]
Abstract
Plants use sunlight as their primary energy source. During photosynthesis, absorbed light energy generates reducing power by driving electron transfer reactions. These are coupled to the transfer of protons into the thylakoid lumen, generating a proton motive force (pmf) required for ATP synthesis. Sudden alterations in light availability have to be met by regulatory mechanisms to avoid the over-accumulation of reactive intermediates and maximize energy efficiency. Here, the acidification of the lumen, as an intermediate product of photosynthesis, plays an important role by regulating photosynthesis in response to excitation energy levels. Recent findings reveal pmf regulation and the modulation of its composition as key determinants for efficient photosynthesis, plant growth, and survival in fluctuating light environments.
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Affiliation(s)
- Ute Armbruster
- Regulation of Photosynthesis Group, Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany.
| | - Viviana Correa Galvis
- Regulation of Photosynthesis Group, Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Hans-Henning Kunz
- Plant Physiology, School of Biological Sciences, Washington State University, P.O. Box 644236, Pullman, WA 99164-4236, USA
| | - Deserah D Strand
- Organelle Biology and Biotechnology Group, Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
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90
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Wege S, Gilliham M, Henderson SW. Chloride: not simply a 'cheap osmoticum', but a beneficial plant macronutrient. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3057-3069. [PMID: 28379459 DOI: 10.1093/jxb/erx050] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
At macronutrient levels, chloride has positive effects on plant growth, which are distinct from its function in photosynthesis..
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Affiliation(s)
- Stefanie Wege
- Australian Research Council Centre of Excellence in Plant Energy Biology & The University of Adelaide, School of Agriculture, Food and Wine, Waite Research Precinct, PMB1, Glen Osmond, South Australia 5064, Australia
| | - Matthew Gilliham
- Australian Research Council Centre of Excellence in Plant Energy Biology & The University of Adelaide, School of Agriculture, Food and Wine, Waite Research Precinct, PMB1, Glen Osmond, South Australia 5064, Australia
| | - Sam W Henderson
- Australian Research Council Centre of Excellence in Plant Energy Biology & The University of Adelaide, School of Agriculture, Food and Wine, Waite Research Precinct, PMB1, Glen Osmond, South Australia 5064, Australia
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91
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Baranov S, Haddy A. An enzyme kinetics study of the pH dependence of chloride activation of oxygen evolution in photosystem II. PHOTOSYNTHESIS RESEARCH 2017; 131:317-332. [PMID: 27896527 DOI: 10.1007/s11120-016-0325-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 11/16/2016] [Indexed: 06/06/2023]
Abstract
Oxygen evolution by photosystem II (PSII) involves activation by Cl- ion, which is regulated by extrinsic subunits PsbQ and PsbP. In this study, the kinetics of chloride activation of oxygen evolution was studied in preparations of PSII depleted of the PsbQ and PsbP subunits (NaCl-washed and Na2SO4/pH 7.5-treated) over a pH range from 5.3 to 8.0. At low pH, activation by chloride was followed by inhibition at chloride concentrations >100 mM, whereas at high pH activation continued as the chloride concentration increased above 100 mM. Both activation and inhibition were more pronounced at lower pH, indicating that Cl- binding depended on protonation events in each case. The simplest kinetic model that could account for the complete data set included binding of Cl- at two sites, one for activation and one for inhibition, and four protonation steps. The intrinsic (pH-independent) dissociation constant for Cl- activation, K S, was found to be 0.9 ± 0.2 mM for both preparations, and three of the four pK as were determined, with the fourth falling below the pH range studied. The intrinsic inhibition constant, K I, was found to be 64 ± 2 and 103 ± 7 mM for the NaCl-washed and Na2SO4/pH7.5-treated preparations, respectively, and is considered in terms of the conditions likely to be present in the thylakoid lumen. This enzyme kinetics analysis provides a more complete characterization of chloride and pH dependence of O2 evolution activity than has been previously presented.
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Affiliation(s)
- Sergei Baranov
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA
| | - Alice Haddy
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA.
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92
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Teardo E, Carraretto L, Wagner S, Formentin E, Behera S, De Bortoli S, Larosa V, Fuchs P, Lo Schiavo F, Raffaello A, Rizzuto R, Costa A, Schwarzländer M, Szabò I. Physiological Characterization of a Plant Mitochondrial Calcium Uniporter in Vitro and in Vivo. PLANT PHYSIOLOGY 2017; 173:1355-1370. [PMID: 28031475 PMCID: PMC5291028 DOI: 10.1104/pp.16.01359] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 12/21/2016] [Indexed: 05/19/2023]
Abstract
Over the recent years, several proteins that make up the mitochondrial calcium uniporter complex (MCUC) mediating Ca2+uptake into the mitochondrial matrix have been identified in mammals, including the channel-forming protein MCU. Although six MCU gene homologs are conserved in the model plant Arabidopsis (Arabidopsis thaliana) in which mitochondria can accumulate Ca2+, a functional characterization of plant MCU homologs has been lacking. Using electrophysiology, we show that one isoform, AtMCU1, gives rise to a Ca2+-permeable channel activity that can be observed even in the absence of accessory proteins implicated in the formation of the active mammalian channel. Furthermore, we provide direct evidence that AtMCU1 activity is sensitive to the mitochondrial calcium uniporter inhibitors Ruthenium Red and Gd3+, as well as to the Arabidopsis protein MICU, a regulatory MCUC component. AtMCU1 is prevalently expressed in roots, localizes to mitochondria, and its absence causes mild changes in Ca2+ dynamics as assessed by in vivo measurements in Arabidopsis root tips. Plants either lacking or overexpressing AtMCU1 display root mitochondria with altered ultrastructure and show shorter primary roots under restrictive growth conditions. In summary, our work adds evolutionary depth to the investigation of mitochondrial Ca2+ transport, indicates that AtMCU1, together with MICU as a regulator, represents a functional configuration of the plant mitochondrial Ca2+ uptake complex with differences to the mammalian MCUC, and identifies a new player of the intracellular Ca2+ regulation network in plants.
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Affiliation(s)
- Enrico Teardo
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy;
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.);
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.);
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Luca Carraretto
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Stephan Wagner
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Elide Formentin
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Smrutisanjita Behera
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Sara De Bortoli
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Véronique Larosa
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Philippe Fuchs
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Fiorella Lo Schiavo
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Anna Raffaello
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Rosario Rizzuto
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Alex Costa
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Markus Schwarzländer
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Ildiko Szabò
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy;
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.);
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.);
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
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93
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Shikanai T, Yamamoto H. Contribution of Cyclic and Pseudo-cyclic Electron Transport to the Formation of Proton Motive Force in Chloroplasts. MOLECULAR PLANT 2017; 10:20-29. [PMID: 27575692 DOI: 10.1016/j.molp.2016.08.004] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 07/28/2016] [Accepted: 08/08/2016] [Indexed: 05/05/2023]
Abstract
Photosynthetic electron transport is coupled to proton translocation across the thylakoid membrane, resulting in the formation of a trans-thylakoid proton gradient (ΔpH) and membrane potential (Δψ). Ion transporters and channels localized to the thylakoid membrane regulate the contribution of each component to the proton motive force (pmf). Although both ΔpH and Δψ contribute to ATP synthesis as pmf, only ΔpH downregulates photosynthetic electron transport via the acidification of the thylakoid lumen by inducing thermal dissipation of excessive absorbed light energy from photosystem II antennae and slowing down of the electron transport through the cytochrome b6f complex. To optimize the tradeoff between efficient light energy utilization and protection of both photosystems against photodamage, plants have to regulate the pmf amplitude and its components, ΔpH and Δψ. Cyclic electron transport around photosystem I (PSI) is a major regulator of the pmf amplitude by generating pmf independently of the net production of NADPH by linear electron transport. Chloroplast ATP synthase relaxes pmf for ATP synthesis, and its activity should be finely tuned for maintaining the size of the pmf during steady-state photosynthesis. Pseudo-cyclic electron transport mediated by flavodiiron protein (Flv) forms a large electron sink, which is essential for PSI photoprotection in fluctuating light in cyanobacteria. Flv is conserved from cyanobacteria to gymnosperms but not in angiosperms. The Arabidopsis proton gradient regulation 5 (pgr5) mutant is defective in the main pathway of PSI cyclic electron transport. By introducing Physcomitrella patens genes encoding Flvs, the function of PSI cyclic electron transport was substituted by that of Flv-dependent pseudo-cyclic electron transport. In transgenic plants, the size of the pmf was complemented to the wild-type level but the contribution of ΔpH to the total pmf was lower than that in the wild type. In the pgr5 mutant, the size of the pmf was drastically lowered by the absence of PSI cyclic electron transport. In the mutant, ΔpH occupied the majority of pmf, suggesting the presence of a mechanism for the homeostasis of luminal pH in the light. To avoid damage to photosynthetic electron transport by periods of excess solar energy, plants employ an intricate regulatory network involving alternative electron transport pathways, ion transporters/channels, and pH-dependent mechanisms for downregulating photosynthetic electron transport.
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Affiliation(s)
- Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 Japan; CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076 Japan.
| | - Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 Japan; CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076 Japan
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94
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Spetea C, Szabò I, Kunz HH. Editorial: Ion Transport in Chloroplast and Mitochondria Physiology in Green Organisms. FRONTIERS IN PLANT SCIENCE 2017; 7:2003. [PMID: 28105038 PMCID: PMC5215122 DOI: 10.3389/fpls.2016.02003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 12/16/2016] [Indexed: 06/06/2023]
Affiliation(s)
- Cornelia Spetea
- Department of Biological and Environmental Sciences, University of GothenburgGothenburg, Sweden
| | - Ildikò Szabò
- Department of Biology, University of PadovaPadova, Italy
- Institute of Neurosciences, CNRPadova, Italy
| | - Hans-Henning Kunz
- Plant Physiology, School of Biological Sciences, Washington State UniversityPullman, WA, USA
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95
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Lyu H, Lazár D. Modeling the light-induced electric potential difference ΔΨ across the thylakoid membrane based on the transition state rate theory. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1858:239-248. [PMID: 28027878 DOI: 10.1016/j.bbabio.2016.12.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 12/01/2016] [Accepted: 12/23/2016] [Indexed: 01/10/2023]
Abstract
In photosynthesis, electron transport-coupled proton movement initiates the formation of the light-induced electric potential difference, ΔΨ, across the thylakoid membrane (TM). Ions are transported across the TM to counterbalance the charge of protons accumulated in the lumen. The objective of this work is to construct range of mathematical models for simulation of ΔΨ, using the transition state rate theory (TSRT) for description of movement of ions through the channels. The TSRT considers either single-ion (TSRT-SI) or multi-ion occupancy (TSRT-MI) in the channels. Movement of ions through the channel pore is described by means of energy barriers and binding sites; ions move in and out of vacant sites with rate constants that depend on the barrier heights and well depths, as well as on the interionic repulsion in TSRT-MI model. Three energy motifs are used to describe the TSRT-SI model: two-barrier one-site (2B1S), three-barrier two-site (3B2S), and four-barrier three-site (4B3S). The 3B2S energy motif is used for the TSRT-MI model. The accumulation of cations due to the TM surface negative fixed charges is also taken into account. A model employing the electro-diffusion theory instead of the TSRT is constructed for comparison. The dual wavelength transmittance signal (ΔA515-560nm) measuring the electrochromic shift (ECS) provides a proxy for experimental light-induced ΔΨ. The simulated ΔΨ traces qualitatively agree with the measured ECS traces. The models can simulate different channel conducting regimes and assess their impact on ΔΨ. The ionic flux coupling in the TSRT-MI model suggests that an increase in the internal or external K+ concentration may block the outward or the inward Mg2+ current, respectively.
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Affiliation(s)
- Hui Lyu
- Department of Biophysics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - Dušan Lazár
- Department of Biophysics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 78371 Olomouc, Czech Republic.
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Kaňa R, Govindjee. Role of Ions in the Regulation of Light-Harvesting. FRONTIERS IN PLANT SCIENCE 2016; 7:1849. [PMID: 28018387 PMCID: PMC5160696 DOI: 10.3389/fpls.2016.01849] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 11/23/2016] [Indexed: 03/03/2024]
Abstract
Regulation of photosynthetic light harvesting in the thylakoids is one of the major key factors affecting the efficiency of photosynthesis. Thylakoid membrane is negatively charged and influences both the structure and the function of the primarily photosynthetic reactions through its electrical double layer (EDL). Further, there is a heterogeneous organization of soluble ions (K+, Mg2+, Cl-) attached to the thylakoid membrane that, together with fixed charges (negatively charged amino acids, lipids), provides an electrical field. The EDL is affected by the valence of the ions and interferes with the regulation of "state transitions," protein interactions, and excitation energy "spillover" from Photosystem II to Photosystem I. These effects are reflected in changes in the intensity of chlorophyll a fluorescence, which is also a measure of photoprotective non-photochemical quenching (NPQ) of the excited state of chlorophyll a. A triggering of NPQ proceeds via lumen acidification that is coupled to the export of positive counter-ions (Mg2+, K+) to the stroma or/and negative ions (e.g., Cl-) into the lumen. The effect of protons and anions in the lumen and of the cations (Mg2+, K+) in the stroma are, thus, functionally tightly interconnected. In this review, we discuss the consequences of the model of EDL, proposed by Barber (1980b) Biochim Biophys Acta 594:253-308) in light of light-harvesting regulation. Further, we explain differences between electrostatic screening and neutralization, and we emphasize the opposite effect of monovalent (K+) and divalent (Mg2+) ions on light-harvesting and on "screening" of the negative charges on the thylakoid membrane; this effect needs to be incorporated in all future models of photosynthetic regulation by ion channels and transporters.
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Affiliation(s)
- Radek Kaňa
- Institute of Microbiology, Academy of Sciences of the CzechiaTřeboň, Czechia
- Faculty of Science, Institute of Chemistry and Biochemistry, University of South BohemiaČeské Budějovice, Czechia
| | - Govindjee
- Center of Biophysics and Quantitative Biology, Department of Biochemistry, Department of Plant Biology, University of Illinois at Urbana-ChampaignUrbana, IL, USA
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