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Ermakova M, Woodford R, Fitzpatrick D, Nix SJ, Zwahlen SM, Farquhar GD, von Caemmerer S, Furbank RT. Chloroplast NADH dehydrogenase-like complex-mediated cyclic electron flow is the main electron transport route in C 4 bundle sheath cells. THE NEW PHYTOLOGIST 2024; 243:2187-2200. [PMID: 39036838 DOI: 10.1111/nph.19982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 06/23/2024] [Indexed: 07/23/2024]
Abstract
The superior productivity of C4 plants is achieved via a metabolic C4 cycle which acts as a CO2 pump across mesophyll and bundle sheath (BS) cells and requires an additional input of energy in the form of ATP. The importance of chloroplast NADH dehydrogenase-like complex (NDH) operating cyclic electron flow (CEF) around Photosystem I (PSI) for C4 photosynthesis has been shown in reverse genetics studies but the contribution of CEF and NDH to cell-level electron fluxes remained unknown. We have created gene-edited Setaria viridis with null ndhO alleles lacking functional NDH and developed methods for quantification of electron flow through NDH in BS and mesophyll cells. We show that CEF accounts for 84% of electrons reducing PSI in BS cells and most of those electrons are delivered through NDH while the contribution of the complex to electron transport in mesophyll cells is minimal. A decreased leaf CO2 assimilation rate and growth of plants lacking NDH cannot be rescued by supplying additional CO2. Our results indicate that NDH-mediated CEF is the primary electron transport route in BS chloroplasts highlighting the essential role of NDH in generating ATP required for CO2 fixation by the C3 cycle in BS cells.
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Affiliation(s)
- Maria Ermakova
- Division of Plant Science, Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Acton, ACT, 2600, Australia
- School of Biological Sciences, Monash University, Melbourne, VIC, 3800, Australia
| | - Russell Woodford
- Division of Plant Science, Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Acton, ACT, 2600, Australia
- School of Biological Sciences, Monash University, Melbourne, VIC, 3800, Australia
| | - Duncan Fitzpatrick
- Division of Plant Science, Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Acton, ACT, 2600, Australia
| | - Samuel J Nix
- Division of Plant Science, Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Acton, ACT, 2600, Australia
| | - Soraya M Zwahlen
- Division of Plant Science, Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Acton, ACT, 2600, Australia
- Division of Developmental Biology, European Molecular Biology Laboratory, 69126, Heidelberg, Germany
| | - Graham D Farquhar
- Division of Plant Science, Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Acton, ACT, 2600, Australia
| | - Susanne von Caemmerer
- Division of Plant Science, Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Acton, ACT, 2600, Australia
| | - Robert T Furbank
- Division of Plant Science, Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Acton, ACT, 2600, Australia
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2
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Sahay S, Grzybowski M, Schnable JC, Głowacka K. Genotype-specific nonphotochemical quenching responses to nitrogen deficit are linked to chlorophyll a to b ratios. JOURNAL OF PLANT PHYSIOLOGY 2024; 297:154261. [PMID: 38705078 DOI: 10.1016/j.jplph.2024.154261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/07/2024]
Abstract
Non-photochemical quenching (NPQ) protects plants from photodamage caused by excess light energy. Substantial variation in NPQ has been reported among different genotypes of the same species. However, comparatively little is known about how environmental perturbations, including nutrient deficits, impact natural variation in NPQ kinetics. Here, we analyzed a natural variation in NPQ kinetics of a diversity panel of 225 maize (Zea mays L.) genotypes under nitrogen replete and nitrogen deficient field conditions. Individual maize genotypes from a diversity panel exhibited a range of changes in NPQ in response to low nitrogen. Replicated genotypes exhibited consistent responses across two field experiments conducted in different years. At the seedling and pre-flowering stages, a similar portion of the genotypes (∼33%) showed decrease, no-change or increase in NPQ under low nitrogen relative to control. Genotypes with increased NPQ under low nitrogen also showed greater reductions in dry biomass and photosynthesis than genotypes with stable NPQ when exposed to low nitrogen conditions. Maize genotypes where an increase in NPQ was observed under low nitrogen also exhibited a reduction in the ratio of chlorophyll a to chlorophyll b. Our results underline that since thermal dissipation of excess excitation energy measured via NPQ helps to balance the energy absorbed with energy utilized, the NPQ changes are the reflection of broader molecular and biochemical changes which occur under the stresses such as low soil fertility. Here, we have demonstrated that variation in NPQ kinetics resulted from genetic and environmental factors, are not independent of each other. Natural genetic variation controlling plastic responses of NPQ kinetics to environmental perturbation increases the likelihood it will be possible to optimize NPQ kinetics in crop plants for different environments.
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Affiliation(s)
- Seema Sahay
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, USA; Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, USA.
| | - Marcin Grzybowski
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, USA; Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, USA; Department of Plant Molecular Ecophysiology, Faculty of Biology, Institute of Plant Experimental Biology and Biotechnology, University of Warsaw, 02-096 Warsaw, Poland.
| | - James C Schnable
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, USA; Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, USA.
| | - Katarzyna Głowacka
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, USA; Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, USA; Institute of Plant Genetics, Polish Academy of Sciences, 60-479, Poznań, Poland.
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3
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Shikanai T. Molecular Genetic Dissection of the Regulatory Network of Proton Motive Force in Chloroplasts. PLANT & CELL PHYSIOLOGY 2024; 65:537-550. [PMID: 38150384 DOI: 10.1093/pcp/pcad157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 11/27/2023] [Accepted: 12/08/2023] [Indexed: 12/29/2023]
Abstract
The proton motive force (pmf) generated across the thylakoid membrane rotates the Fo-ring of ATP synthase in chloroplasts. The pmf comprises two components: membrane potential (∆Ψ) and proton concentration gradient (∆pH). Acidification of the thylakoid lumen resulting from ∆pH downregulates electron transport in the cytochrome b6f complex. This process, known as photosynthetic control, is crucial for protecting photosystem I (PSI) from photodamage in response to fluctuating light. To optimize the balance between efficient photosynthesis and photoprotection, it is necessary to regulate pmf. Cyclic electron transport around PSI and pseudo-cyclic electron transport involving flavodiiron proteins contribute to the modulation of pmf magnitude. By manipulating the ratio between the two components of pmf, it is possible to modify the extent of photosynthetic control without affecting the pmf size. This adjustment can be achieved by regulating the movement of ions (such as K+ and Cl-) across the thylakoid membrane. Since ATP synthase is the primary consumer of pmf in chloroplasts, its activity must be precisely regulated to accommodate other mechanisms involved in pmf optimization. Although fragments of information about each regulatory process have been accumulated, a comprehensive understanding of their interactions is lacking. Here, I summarize current knowledge of the network for pmf regulation, mainly based on genetic studies.
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Affiliation(s)
- Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan
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4
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Xiao J, Zhou Y, Xie Y, Li T, Su X, He J, Jiang Y, Zhu H, Qu H. ATP homeostasis and signaling in plants. PLANT COMMUNICATIONS 2024; 5:100834. [PMID: 38327057 PMCID: PMC11009363 DOI: 10.1016/j.xplc.2024.100834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 01/14/2024] [Accepted: 02/03/2024] [Indexed: 02/09/2024]
Abstract
ATP is the primary form of energy for plants, and a shortage of cellular ATP is generally acknowledged to pose a threat to plant growth and development, stress resistance, and crop quality. The overall metabolic processes that contribute to the ATP pool, from production, dissipation, and transport to elimination, have been studied extensively. Considerable evidence has revealed that in addition to its role in energy supply, ATP also acts as a regulatory signaling molecule to activate global metabolic responses. Identification of the eATP receptor DORN1 contributed to a better understanding of how plants cope with disruption of ATP homeostasis and of the key points at which ATP signaling pathways intersect in cells or whole organisms. The functions of SnRK1α, the master regulator of the energy management network, in restoring the equilibrium of the ATP pool have been demonstrated, and the vast and complex metabolic network mediated by SnRK1α to adapt to fluctuating environments has been characterized. This paper reviews recent advances in understanding the regulatory control of the cellular ATP pool and discusses possible interactions among key regulators of ATP-pool homeostasis and crosstalk between iATP/eATP signaling pathways. Perception of ATP deficit and modulation of cellular ATP homeostasis mediated by SnRK1α in plants are discussed at the physiological and molecular levels. Finally, we suggest future research directions for modulation of plant cellular ATP homeostasis.
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Affiliation(s)
- Jiaqi Xiao
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yijie Zhou
- Guangdong AIB Polytechnic, Guangzhou 510507, China
| | - Yunyun Xie
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Taotao Li
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinguo Su
- Guangdong AIB Polytechnic, Guangzhou 510507, China
| | - Junxian He
- School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Yueming Jiang
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong Zhu
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Hongxia Qu
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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5
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Tikhonov AN. The cytochrome b 6f complex: plastoquinol oxidation and regulation of electron transport in chloroplasts. PHOTOSYNTHESIS RESEARCH 2024; 159:203-227. [PMID: 37369875 DOI: 10.1007/s11120-023-01034-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023]
Abstract
In oxygenic photosynthetic systems, the cytochrome b6f (Cytb6f) complex (plastoquinol:plastocyanin oxidoreductase) is a heart of the hub that provides connectivity between photosystems (PS) II and I. In this review, the structure and function of the Cytb6f complex are briefly outlined, being focused on the mechanisms of a bifurcated (two-electron) oxidation of plastoquinol (PQH2). In plant chloroplasts, under a wide range of experimental conditions (pH and temperature), a diffusion of PQH2 from PSII to the Cytb6f does not limit the intersystem electron transport. The overall rate of PQH2 turnover is determined mainly by the first step of the bifurcated oxidation of PQH2 at the catalytic site Qo, i.e., the reaction of electron transfer from PQH2 to the Fe2S2 cluster of the high-potential Rieske iron-sulfur protein (ISP). This point has been supported by the quantum chemical analysis of PQH2 oxidation within the framework of a model system including the Fe2S2 cluster of the ISP and surrounding amino acids, the low-potential heme b6L, Glu78 and 2,3,5-trimethylbenzoquinol (the tail-less analog of PQH2). Other structure-function relationships and mechanisms of electron transport regulation of oxygenic photosynthesis associated with the Cytb6f complex are briefly outlined: pH-dependent control of the intersystem electron transport and the regulatory balance between the operation of linear and cyclic electron transfer chains.
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Affiliation(s)
- Alexander N Tikhonov
- Department of Biophysics, Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow, Russian Federation, 119991.
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6
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Yang QY, Wang XQ, Yang YJ, Huang W. Fluctuating light induces a significant photoinhibition of photosystem I in maize. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 207:108426. [PMID: 38340689 DOI: 10.1016/j.plaphy.2024.108426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/19/2024] [Accepted: 02/04/2024] [Indexed: 02/12/2024]
Abstract
In nature, light intensity usually fluctuates and a sudden shade-sun transition can induce photodamage to photosystem I (PSI) in many angiosperms. Photosynthetic regulation in fluctuating light (FL) has been studied extensively in C3 plants; however, little is known about how C4 plants cope FL to prevent PSI photoinhibition. We here compared photosynthetic responses to FL between maize (Zea mays, C4) and tomato (Solanum lycopersicum, C3) grown under full sunlight. Maize leaves had significantly higher cyclic electron flow (CEF) activity and lower photorespiration activity than tomato. Upon a sudden shade-sun transition, maize showed a significant stronger transient PSI over-reduction than tomato, resulting in a significant greater PSI photoinhibition in maize after FL treatment. During the first seconds upon shade-sun transition, CEF was stimulated in maize at a much higher extent than tomato, favoring the rapid formation of trans-thylakoid proton gradient (ΔpH), which was helped by a transient down-regulation of chloroplast ATP synthase activity. Therefore, modulation of ΔpH by regulation of CEF and chloroplast ATP synthase adjusted PSI redox state at donor side, which partially compensated for the deficiency of photorespiration. We propose that C4 plants use different photosynthetic strategies for coping with FL as compared with C3 plants.
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Affiliation(s)
- Qiu-Yan Yang
- School of Life Sciences, Shannxi Normal University, Xi'an, 710119, China; Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Xiao-Qian Wang
- School of Life Sciences, Shannxi Normal University, Xi'an, 710119, China
| | - Ying-Jie Yang
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, Kunming, 650205, China.
| | - Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
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7
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Yamamoto H, Cheuk A, Shearman J, Nixon PJ, Meier T, Shikanai T. Impact of engineering the ATP synthase rotor ring on photosynthesis in tobacco chloroplasts. PLANT PHYSIOLOGY 2023; 192:1221-1233. [PMID: 36703219 PMCID: PMC10231360 DOI: 10.1093/plphys/kiad043] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 01/05/2023] [Accepted: 01/06/2023] [Indexed: 06/01/2023]
Abstract
The chloroplast ATP synthase produces the ATP needed for photosynthesis and plant growth. The trans-membrane flow of protons through the ATP synthase rotates an oligomeric assembly of c subunits, the c-ring. The ion-to-ATP ratio in rotary F1F0-ATP synthases is defined by the number of c-subunits in the rotor c-ring. Engineering the c-ring stoichiometry is, therefore, a possible route to manipulate ATP synthesis by the ATP synthase and hence photosynthetic efficiency in plants. Here, we describe the construction of a tobacco (Nicotiana tabacum) chloroplast atpH (chloroplastic ATP synthase subunit c gene) mutant in which the c-ring stoichiometry was increased from 14 to 15 c-subunits. Although the abundance of the ATP synthase was decreased to 25% of wild-type (WT) levels, the mutant lines grew as well as WT plants and photosynthetic electron transport remained unaffected. To synthesize the necessary ATP for growth, we found that the contribution of the membrane potential to the proton motive force was enhanced to ensure a higher proton flux via the c15-ring without unwanted low pH-induced feedback inhibition of electron transport. Our work opens avenues to manipulate plant ion-to-ATP ratios with potentially beneficial consequences for photosynthesis.
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Affiliation(s)
- Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Anthony Cheuk
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington Campus, London SW7 2AZ, UK
| | - Julia Shearman
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington Campus, London SW7 2AZ, UK
| | - Peter J Nixon
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington Campus, London SW7 2AZ, UK
| | - Thomas Meier
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington Campus, London SW7 2AZ, UK
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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8
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von Bismarck T, Korkmaz K, Ruß J, Skurk K, Kaiser E, Correa Galvis V, Cruz JA, Strand DD, Köhl K, Eirich J, Finkemeier I, Jahns P, Kramer DM, Armbruster U. Light acclimation interacts with thylakoid ion transport to govern the dynamics of photosynthesis in Arabidopsis. THE NEW PHYTOLOGIST 2023; 237:160-176. [PMID: 36378135 DOI: 10.1111/nph.18534] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
Understanding photosynthesis in natural, dynamic light environments requires knowledge of long-term acclimation, short-term responses, and their mechanistic interactions. To approach the latter, we systematically determined and characterized light-environmental effects on thylakoid ion transport-mediated short-term responses during light fluctuations. For this, Arabidopsis thaliana wild-type and mutants of the Cl- channel VCCN1 and the K+ exchange antiporter KEA3 were grown under eight different light environments and characterized for photosynthesis-associated parameters and factors in steady state and during light fluctuations. For a detailed characterization of selected light conditions, we monitored ion flux dynamics at unprecedented high temporal resolution by a modified spectroscopy approach. Our analyses reveal that daily light intensity sculpts photosynthetic capacity as a main acclimatory driver with positive and negative effects on the function of KEA3 and VCCN1 during high-light phases, respectively. Fluctuations in light intensity boost the accumulation of the photoprotective pigment zeaxanthin (Zx). We show that KEA3 suppresses Zx accumulation during the day, which together with its direct proton transport activity accelerates photosynthetic transition to lower light intensities. In summary, both light-environment factors, intensity and variability, modulate the function of thylakoid ion transport in dynamic photosynthesis with distinct effects on lumen pH, Zx accumulation, photoprotection, and photosynthetic efficiency.
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Affiliation(s)
| | - Kübra Korkmaz
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Jeremy Ruß
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Kira Skurk
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Elias Kaiser
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | | | - Jeffrey A Cruz
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Deserah D Strand
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Karin Köhl
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Jürgen Eirich
- Plant Physiology, Institute of Plant Biology and Biotechnology, University of Münster, 48149, Münster, Germany
| | - Iris Finkemeier
- Plant Physiology, Institute of Plant Biology and Biotechnology, University of Münster, 48149, Münster, Germany
| | - Peter Jahns
- Plant Biochemistry, Heinrich-Heine-University Düsseldorf, 40225, Düsseldorf, Germany
| | - David M Kramer
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Ute Armbruster
- Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
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9
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Photoinhibition of Photosystem I Induced by Different Intensities of Fluctuating Light Is Determined by the Kinetics of ∆pH Formation Rather Than Linear Electron Flow. Antioxidants (Basel) 2022; 11:antiox11122325. [PMID: 36552532 PMCID: PMC9774317 DOI: 10.3390/antiox11122325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 11/16/2022] [Accepted: 11/16/2022] [Indexed: 11/25/2022] Open
Abstract
Fluctuating light (FL) can cause the selective photoinhibition of photosystem I (PSI) in angiosperms. In nature, leaves usually experience FL conditions with the same low light and different high light intensities, but the effects of different FL conditions on PSI redox state and PSI photoinhibition are not well known. In this study, we found that PSI was highly reduced within the first 10 s after transition from 59 to 1809 μmol photons m-2 s-1 in tomato (Solanum lycopersicum). However, such transient PSI over-reduction was not observed by transitioning from 59 to 501 or 923 μmol photons m-2 s-1. Consequently, FL (59-1809) induced a significantly stronger PSI photoinhibition than FL (59-501) and FL (59-923). Compared with the proton gradient (∆pH) level after transition to high light for 60 s, tomato leaves almost formed a sufficient ∆pH after light transition for 10 s in FL (59-501) but did not in FL (59-923) or FL (59-1809). The difference in ∆pH between 10 s and 60 s was tightly correlated to the extent of PSI over-reduction and PSI photoinhibition induced by FL. Furthermore, the difference in PSI photoinhibition between (59-923) and FL (59-1809) was accompanied by the same level of linear electron flow. Therefore, PSI photoinhibition induced by different intensities of FL is more related to the kinetics of ∆pH formation rather than linear electron flow.
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10
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Cheng JB, Zhang SB, Wu JS, Huang W. The Dynamic Changes of Alternative Electron Flows upon Transition from Low to High Light in the Fern Cyrtomium fortune and the Gymnosperm Nageia nagi. Cells 2022; 11:cells11172768. [PMID: 36078176 PMCID: PMC9455243 DOI: 10.3390/cells11172768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/10/2022] [Accepted: 08/22/2022] [Indexed: 12/02/2022] Open
Abstract
In photosynthetic organisms except angiosperms, an alternative electron sink that is mediated by flavodiiron proteins (FLVs) plays the major role in preventing PSI photoinhibition while cyclic electron flow (CEF) is also essential for normal growth under fluctuating light. However, the dynamic changes of FLVs and CEF has not yet been well clarified. In this study, we measured the P700 signal, chlorophyll fluorescence, and electrochromic shift spectra in the fern Cyrtomium fortune and the gymnosperm Nageia nagi. We found that both species could not build up a sufficient proton gradient (∆pH) within the first 30 s after light abruptly increased. During this period, FLVs-dependent alternative electron flow was functional to avoid PSI over-reduction. This functional time of FLVs was much longer than previously thought. By comparison, CEF was highly activated within the first 10 s after transition from low to high light, which favored energy balancing rather than the regulation of a PSI redox state. When FLVs were inactivated during steady-state photosynthesis, CEF was re-activated to favor photoprotection and to sustain photosynthesis. These results provide new insight into how FLVs and CEF interact to regulate photosynthesis in non-angiosperms.
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Affiliation(s)
- Jun-Bin Cheng
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shi-Bao Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Jin-Song Wu
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- Correspondence:
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11
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Regulation of Chloroplast ATP Synthase Modulates Photoprotection in the CAM Plant Vanilla planifolia. Cells 2022; 11:cells11101647. [PMID: 35626684 PMCID: PMC9139848 DOI: 10.3390/cells11101647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/09/2022] [Accepted: 05/10/2022] [Indexed: 11/27/2022] Open
Abstract
Generally, regulation of cyclic electron flow (CEF) and chloroplast ATP synthase play key roles in photoprotection for photosystems I and II (PSI and PSII) in C3 and C4 plants, especially when CO2 assimilation is restricted. However, how CAM plants protect PSI and PSII when CO2 assimilation is restricted is largely known. In the present study, we measured PSI, PSII, and electrochromic shift signals in the CAM plant Vanilla planifolia. The quantum yields of PSI and PSII photochemistry largely decreased in the afternoon compared to in the morning, indicating that CO2 assimilation was strongly restricted in the afternoon. Meanwhile, non-photochemical quenching (NPQ) in PSII and the donor side limitation of PSI (Y(ND)) significantly increased to protect PSI and PSII. Under such conditions, proton gradient (∆pH) across the thylakoid membranes largely increased and CEF was slightly stimulated, indicating that the increased ∆pH was not caused by the regulation of CEF. In contrast, the activity of chloroplast ATP synthase (gH+) largely decreased in the afternoon. At a given proton flux, the decreasing gH+ increased ∆pH and thus contributed to the enhancement of NPQ and Y(ND). Therefore, in the CAM plant V. planifolia, the ∆pH-dependent photoprotective mechanism is mainly regulated by the regulation of gH+ rather than CEF when CO2 assimilation is restricted.
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12
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Zhao J, Jiang Y, Tian Y, Mao J, Wei L, Ma W. New insights into the effect of NdhO levels on cyanobacterial cell death triggered by high temperature. FUNCTIONAL PLANT BIOLOGY : FPB 2022; 49:533-541. [PMID: 34428393 DOI: 10.1071/fp21097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 08/05/2021] [Indexed: 06/13/2023]
Abstract
NdhO, a regulatory oxygenic photosynthesis-specific subunit, is close to the ferredoxin-binding site of cyanobacterial NDH-1, and its levels are negatively associated with the rates of cyclic electron transfer around PSI mediated by NDH-1 (NDH-CET). However, the effect of NdhO levels on cyanobacterial cell death triggered by high temperature remains elusive. Here, our results uncovered a synergistic effect of NdhO levels on the cell death and reactive oxygen species (ROS) accumulation when cyanobacterial cells grown at 30°C for 1 day were transferred to 45°C for 2 days. Such synergistic effect was found to be closely associated with the activities of NDH-CET and CO2 assimilation during high temperature. Collectively, we propose that the effect of NdhO levels on the cyanobacterial cell bleaching and cell death triggered by high temperature is a result of influencing production of ROS by NDH-CET, which is considered to be vital to balance the ATP/NADPH ratio and improve the Calvin-Benson cycle.
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Affiliation(s)
- Jiaohong Zhao
- Shanghai Key laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai 200234, China
| | - Yuanyuan Jiang
- Shanghai Key laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai 200234, China
| | - Yuhao Tian
- Shanghai Key laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai 200234, China
| | - Jun Mao
- Shanghai Key laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai 200234, China
| | - Lanzhen Wei
- Shanghai Key laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai 200234, China; and Corresponding author
| | - Weimin Ma
- Shanghai Key laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai 200234, China; and Corresponding author
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13
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Zuo G, Aiken RM, Feng N, Zheng D, Zhao H, Avenson TJ, Lin X. Fresh perspectives on an established technique: Pulsed amplitude modulation chlorophyll a fluorescence. PLANT-ENVIRONMENT INTERACTIONS (HOBOKEN, N.J.) 2022; 3:41-59. [PMID: 37284008 PMCID: PMC10168060 DOI: 10.1002/pei3.10073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 02/22/2022] [Accepted: 02/25/2022] [Indexed: 06/08/2023]
Abstract
Pulsed amplitude modulation (PAM) chlorophyll a fluorescence provides information about photosynthetic energy transduction. When reliably measured, chlorophyll a fluorescence provides detailed information about critical in vivo photosynthetic processes. Such information has recently provided novel and critical insights into how the yield potential of crops can be improved and it is being used to understand remotely sensed fluorescence, which is termed solar-induced fluorescence and will be solely measured by a satellite scheduled to be launched this year. While PAM chlorophyll a fluorometers measure fluorescence intensity per se, herein we articulate the axiomatic criteria by which instrumentally detected intensities can be assumed to assess fluorescence yield, a phenomenon quite different than fluorescence intensity and one that provides critical insight about how solar energy is variably partitioned into the biosphere. An integrated mathematical, phenomenological, and practical discussion of many useful chlorophyll a fluorescence parameters is presented. We draw attention to, and provide examples of, potential uncertainties that can result from incorrect methodological practices and potentially problematic instrumental design features. Fundamentals of fluorescence measurements are discussed, including the major assumptions underlying the signals and the methodological caveats about taking measurements during both dark- and light-adapted conditions. Key fluorescence parameters are discussed in the context of recent applications under environmental stress. Nuanced information that can be gleaned from intra-comparisons of fluorescence-derived parameters and intercomparisons of fluorescence-derived parameters with those based on other techniques is elucidated.
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Affiliation(s)
- Guanqiang Zuo
- Department of AgronomyKansas State UniversityManhattanKansasUSA
| | - Robert M. Aiken
- Department of AgronomyKansas State UniversityManhattanKansasUSA
- Northwest Research‐Extension CenterKansas State UniversityColbyKansasUSA
| | - Naijie Feng
- College of Coastal Agricultural ScienceGuangdong Ocean UniversityZhanjiangChina
- Shenzhen Research Institute of Guangdong Ocean UniversityShenzhenChina
| | - Dianfeng Zheng
- College of Coastal Agricultural ScienceGuangdong Ocean UniversityZhanjiangChina
- Shenzhen Research Institute of Guangdong Ocean UniversityShenzhenChina
| | - Haidong Zhao
- Department of AgronomyKansas State UniversityManhattanKansasUSA
| | | | - Xiaomao Lin
- Department of AgronomyKansas State UniversityManhattanKansasUSA
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14
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Uflewski M, Mielke S, Correa Galvis V, von Bismarck T, Chen X, Tietz E, Ruß J, Luzarowski M, Sokolowska E, Skirycz A, Eirich J, Finkemeier I, Schöttler MA, Armbruster U. Functional characterization of proton antiport regulation in the thylakoid membrane. PLANT PHYSIOLOGY 2021; 187:2209-2229. [PMID: 33742682 PMCID: PMC8644300 DOI: 10.1093/plphys/kiab135] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 03/03/2021] [Indexed: 05/21/2023]
Abstract
During photosynthesis, energy is transiently stored as an electrochemical proton gradient across the thylakoid membrane. The resulting proton motive force (pmf) is composed of a membrane potential (ΔΨ) and a proton concentration gradient (ΔpH) and powers the synthesis of ATP. Light energy availability for photosynthesis can change very rapidly and frequently in nature. Thylakoid ion transport proteins buffer the effects that light fluctuations have on photosynthesis by adjusting pmf and its composition. Ion channel activities dissipate ΔΨ, thereby reducing charge recombinations within photosystem II. The dissipation of ΔΨ allows for increased accumulation of protons in the thylakoid lumen, generating the signal that activates feedback downregulation of photosynthesis. Proton export from the lumen via the thylakoid K+ exchange antiporter 3 (KEA3), instead, decreases the ΔpH fraction of the pmf and thereby reduces the regulatory feedback signal. Here, we reveal that the Arabidopsis (Arabidopsis thaliana) KEA3 protein homo-dimerizes via its C-terminal domain. This C-terminus has a regulatory function, which responds to light intensity transients. Plants carrying a C-terminus-less KEA3 variant show reduced feed-back downregulation of photosynthesis and suffer from increased photosystem damage under long-term high light stress. However, during photosynthetic induction in high light, KEA3 deregulation leads to an increase in carbon fixation rates. Together, the data reveal a trade-off between long-term photoprotection and a short-term boost in carbon fixation rates, which is under the control of the KEA3 C-terminus.
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Affiliation(s)
- Michał Uflewski
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | - Sarah Mielke
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | | | | | - Xiaoheng Chen
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | - Enrico Tietz
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | - Jeremy Ruß
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | - Marcin Luzarowski
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | - Ewelina Sokolowska
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | - Aleksandra Skirycz
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
- Boyce Thompson Institute, Ithaca 14853, New York
| | - Jürgen Eirich
- Plant Physiology, Institute of Plant Biology and Biotechnology, University of Münster, Münster 48149, Germany
| | - Iris Finkemeier
- Plant Physiology, Institute of Plant Biology and Biotechnology, University of Münster, Münster 48149, Germany
| | | | - Ute Armbruster
- Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
- Author for communication:
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15
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Trinh MDL, Hashimoto A, Kono M, Takaichi S, Nakahira Y, Masuda S. Lack of plastid-encoded Ycf10, a homolog of the nuclear-encoded DLDG1 and the cyanobacterial PxcA, enhances the induction of non-photochemical quenching in tobacco. PLANT DIRECT 2021; 5:e368. [PMID: 34938941 PMCID: PMC8671777 DOI: 10.1002/pld3.368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 05/05/2023]
Abstract
pH homeostasis in the chloroplast is crucial for the control of photosynthesis and other metabolic processes in plants. Recently, nuclear-encoded Day-Length-dependent Delayed Greening1 (DLDG1) and Fluctuating-Light Acclimation Protein1 (FLAP1) that are required for the light-inducible optimization of plastidial pH in Arabidopsis thaliana were identified. DLDG1 and FLAP1 homologs are specifically conserved in oxygenic phototrophs, and a DLDG1 homolog, Ycf10, is encoded in the chloroplast genome in plant cells. However, the function of Ycf10 and its physiological significance are unknown. To address this, we constructed ycf10 tobacco Nicotiana tabacum mutants and characterized their phenotypes. The ycf10 tobacco mutants grown under continuous-light conditions showed a pale-green phenotype only in developing leaves, and it was suppressed in short-day conditions. The ycf10 mutants also induced excessive non-photochemical quenching (NPQ) compared with those in the wild-type at the induction stage of photosynthesis. These phenotypes resemble those of Arabidopsis dldg1 mutants, suggesting that they have similar functions. However, there are distinct differences between the two mutant phenotypes: The highly induced NPQ in tobacco ycf10 and the Arabidopsis dldg1 mutants are diminished and enhanced, respectively, with increasing duration of the fluctuating actinic-light illumination. Ycf10 and DLDG1 were previously shown to localize in chloroplast envelope-membranes, suggesting that Ycf10 and DLDG1 differentially control H+ exchange across these membranes in a light-dependent manner to control photosynthesis.
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Affiliation(s)
- Mai Duy Luu Trinh
- Department of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Akira Hashimoto
- Department of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
| | - Masaru Kono
- Department of Biological Science, Graduate School of ScienceThe University of TokyoTokyoJapan
| | - Shinichi Takaichi
- Department of Molecular MicrobiologyTokyo University of AgricultureTokyoJapan
| | | | - Shinji Masuda
- Department of Life Science and TechnologyTokyo Institute of TechnologyYokohamaJapan
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16
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Chovancek E, Zivcak M, Brestic M, Hussain S, Allakhverdiev SI. The different patterns of post-heat stress responses in wheat genotypes: the role of the transthylakoid proton gradient in efficient recovery of leaf photosynthetic capacity. PHOTOSYNTHESIS RESEARCH 2021; 150:179-193. [PMID: 33393064 DOI: 10.1007/s11120-020-00812-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 12/08/2020] [Indexed: 05/28/2023]
Abstract
The frequency and severity of heat waves are expected to increase in the near future, with a significant impact on physiological functions and yield of crop plants. In this study, we assessed the residual post-heat stress effects on photosynthetic responses of six diverse winter wheat (Triticum sp.) genotypes, differing in country of origin, taxonomy and ploidy (tetraploids vs. hexaploids). After 5 days of elevated temperatures (up to 38 °C), the photosynthetic parameters recorded on the first day of recovery (R1) as well as after the next 4-5 days of the recovery (R2) were compared to those of the control plants (C) grown under moderate temperatures. Based on the values of CO2 assimilation rate (A) and the maximum rates of carboxylation (VCmax) in R1, we identified that the hexaploid (HEX) and tetraploid (TET) species clearly differed in the strength of their response to heat stress. Next, the analyses of gas exchange, simultaneous measurements of PSI and PSII photochemistry and the measurements of electrochromic bandshift (ECS) have consistently shown that photosynthetic and photoprotective functions in leaves of TET genotypes were almost fully recovered in R2, whereas the recovery of photosynthetic and photoprotective functions in the HEX group in R2 was still rather low. A poor recovery was associated with an overly reduced acceptor side of photosystem I as well as high values of the electric membrane potential (Δψ component of the proton motive force, pmf) in the chloroplast. On the other hand, a good recovery of photosynthetic capacity and photoprotective functions was clearly associated with an enhanced ΔpH component of the pmf, thus demonstrating a key role of efficient regulation of proton transport to ensure buildup of the transthylakoid proton gradient needed for photosynthesis restoration after high-temperature episodes.
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Affiliation(s)
- Erik Chovancek
- Department of Plant Physiology, Slovak University of Agriculture, Nitra, Slovak Republic
| | - Marek Zivcak
- Department of Plant Physiology, Slovak University of Agriculture, Nitra, Slovak Republic.
| | - Marian Brestic
- Department of Plant Physiology, Slovak University of Agriculture, Nitra, Slovak Republic
| | - Sajad Hussain
- College of Agronomy, Sichuan Agricultural University, Chengdu, People's Republic of China
- Sichuan Engineering Research Center for Crop Strip Intercropping System, Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Sichuan Agricultural University, Chengdu, People's Republic of China
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17
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Yang YJ, Sun H, Zhang SB, Huang W. Roles of alternative electron flows in response to excess light in Ginkgo biloba. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 312:111030. [PMID: 34620434 DOI: 10.1016/j.plantsci.2021.111030] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 08/17/2021] [Accepted: 08/20/2021] [Indexed: 06/13/2023]
Abstract
Ginkgo biloba L., the only surviving species of Ginkgoopsida, is a famous relict gymnosperm, it may provide new insight into the evolution of photosynthetic mechanisms. Flavodiiron proteins (FDPs) are conserved in nonflowering plants, but the role of FDPs in gymnosperms has not yet been clarified. In particular, how gymnosperms integrate FDPs and cyclic electron transport (CET) to better adapt to excess light is poorly understood. To elucidate these questions, we measured the P700 signal, chlorophyll fluorescence and electrochromic shift signal under fluctuating and constant light in G. biloba. Within the first seconds after light increased, G. biloba could not build up a sufficient proton gradient (ΔpH). Concomitantly, photo-reduction of O2 mediated by FDPs contributed to the rapid oxidation of P700 and protected PSI under fluctuating light. Therefore, in G. biloba, FDPs mainly protect PSI under fluctuating light at acceptor side. Under constant high light, the oxidation of PSI and the induction of non-photochemical quenching were attributed to the increase in ΔpH formation, which was mainly caused by the increase in CET rather than linear electron transport. Therefore, under constant light, CET finely regulates the PSI redox state and non-photochemical quenching through ΔpH formation, protecting PSI and PSII against excess light. We conclude that, in G. biloba, FDPs are particularly important under fluctuating light while CET is essential under constant high light. The coordination of FDPs and CET fine-tune photosynthetic apparatus under excess light.
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Affiliation(s)
- Ying-Jie Yang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hu Sun
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shi-Bao Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
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18
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Lei YB, Xia HX, Chen K, Plenković-Moraj A, Huang W, Sun G. Photosynthetic regulation in response to fluctuating light conditions under temperature stress in three mosses with different light requirements. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 311:111020. [PMID: 34482921 DOI: 10.1016/j.plantsci.2021.111020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 08/05/2021] [Accepted: 08/07/2021] [Indexed: 06/13/2023]
Abstract
Under natural field conditions, mosses experience fluctuating light intensities combined with temperature stress. Alternative electron flow mediated by flavodiiron proteins (FLVs) and cyclic electron flow (CEF) around photosystem I (PSI) allow mosses to growth under fluctuating light conditions. However, little is known about the roles of FLVs and CEF in the regulation of photosynthesis under temperature stress combined with fluctuating light. Here, we measured chlorophyll fluorescence and P700 redox state under fluctuating light conditions at 4 °C, 20 °C, and 35 °C in three mosses with different light requirements. Upon a sudden increase in light intensity, electron flow from photosystem II initially increased and then gradually decreased at 20 °C and 35 °C, indicating that the operation of FLV-dependent flow lasted much longer than previously thought. Furthermore, the absolute rates of FLV-dependent flow and CEF were enhanced under fluctuating light at 35 °C, pointing to their important roles in photoprotection when exposed to fluctuating light at moderate high temperature. Furthermore, the downregulation of FLV activity at 4 °C was partially compensated for by enhanced CEF activity. These results suggested the subtle coordination between FLV activity and CEF under fluctuating light and temperature stress. Racomitrium japonicum and Hypnum plumaeforme, which usually grow under relatively high light levels, exhibited higher FLV activity and CEF than the shade-grown moss Plagiomnium ellipticum. Based on our results, we conclude that photosynthetic acclimation to fluctuating light and temperature stress in different mosses is largely linked to the adjustment of FLV activity and CEF.
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Affiliation(s)
- Yan-Bao Lei
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Biodiversity Conservation Key Laboratory of Sichuan Province & China-Croatia "Belt and Road" Joint Laboratory on Biodiversity and Ecosystem Services, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Hong-Xia Xia
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Biodiversity Conservation Key Laboratory of Sichuan Province & China-Croatia "Belt and Road" Joint Laboratory on Biodiversity and Ecosystem Services, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China; School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Ke Chen
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Anđelka Plenković-Moraj
- Department of Biology, Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000, Zagreb, Croatia
| | - Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
| | - Geng Sun
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Biodiversity Conservation Key Laboratory of Sichuan Province & China-Croatia "Belt and Road" Joint Laboratory on Biodiversity and Ecosystem Services, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.
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19
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Yin X, Busch FA, Struik PC, Sharkey TD. Evolution of a biochemical model of steady-state photosynthesis. PLANT, CELL & ENVIRONMENT 2021; 44:2811-2837. [PMID: 33872407 PMCID: PMC8453732 DOI: 10.1111/pce.14070] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 04/10/2021] [Accepted: 04/12/2021] [Indexed: 05/29/2023]
Abstract
On the occasion of the 40th anniversary of the publication of the landmark model by Farquhar, von Caemmerer & Berry on steady-state C3 photosynthesis (known as the "FvCB model"), we review three major further developments of the model. These include: (1) limitation by triose phosphate utilization, (2) alternative electron transport pathways, and (3) photorespiration-associated nitrogen and C1 metabolisms. We discussed the relation of the third extension with the two other extensions, and some equivalent extensions to model C4 photosynthesis. In addition, the FvCB model has been coupled with CO2 -diffusion models. We review how these extensions and integration have broadened the use of the FvCB model in understanding photosynthesis, especially with regard to bioenergetic stoichiometries associated with photosynthetic quantum yields. Based on the new insights, we present caveats in applying the FvCB model. Further research needs are highlighted.
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Affiliation(s)
- Xinyou Yin
- Centre for Crop Systems AnalysisWageningen University & ResearchWageningenThe Netherlands
| | - Florian A. Busch
- School of Biosciences and Birmingham Institute of Forest ResearchUniversity of BirminghamBirminghamUK
| | - Paul C. Struik
- Centre for Crop Systems AnalysisWageningen University & ResearchWageningenThe Netherlands
| | - Thomas D. Sharkey
- MSU‐DOE Plant Research Laboratory, Plant Resilience InstituteMichigan State UniversityEast LansingMichiganUSA
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20
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Cruz JA, Avenson TJ. Photosynthesis: a multiscopic view. JOURNAL OF PLANT RESEARCH 2021; 134:665-682. [PMID: 34170422 DOI: 10.1007/s10265-021-01321-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 06/11/2021] [Indexed: 06/13/2023]
Abstract
A recurring analogy for photosynthesis research is the fable of the blind men and the elephant. Photosynthesis has many complex working parts, which has driven the need to study each of them individually, with an inherent understanding that a more complete picture will require systematic integration of these views. However, unlike the blind men, who are limited to using their hands, researchers have developed over the past decades a repertoire of methods for studying these components, many of which capitalize on unique features intrinsic to each. More recent concerns about food security and clean, renewable energy have increased support for applied photosynthesis research, with the idea of either improving photosynthetic performance as a desired trait in select species or using photosynthetic measurements as a phenotyping tool in breeding efforts or for high precision crop management. In this review, we spotlight the migration of approaches for studying photosynthesis from the laboratory into field environments, highlight some recent advances and speculate on areas where further development would be fruitful, with an eye towards how applied photosynthesis research can have impacts at local and global scales.
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Affiliation(s)
- Jeffrey A Cruz
- Plant Research Laboratories, Michigan State University, 612 Wilson Road, MI, S-206, Lansing, USA.
- Department of Biochemistry and Molecular Biology, Michigan State University, Lansing, MI, USA.
| | - Thomas J Avenson
- Department of Plant Sciences, University of Cambridge, CB2 9EW, Cambridge, UK
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21
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Different Strategies for Photosynthetic Regulation under Fluctuating Light in Two Sympatric Paphiopedilum Species. Cells 2021; 10:cells10061451. [PMID: 34200524 PMCID: PMC8229141 DOI: 10.3390/cells10061451] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 05/30/2021] [Accepted: 06/02/2021] [Indexed: 01/10/2023] Open
Abstract
Fluctuating light can cause selective photoinhibition of photosystem I (PSI) in angiosperms. Cyclic electron flow (CEF) around PSI and electron flux from water via the electron transport chain to oxygen (the water-water cycle) play important roles in coping with fluctuating light in angiosperms. However, it is unclear whether plant species in the same genus employ the same strategy to cope with fluctuating light. To answer this question, we measured P700 redox kinetics and chlorophyll fluorescence under fluctuating light in two Paphiopedilum (P.) Pftzer (Orchidaceae) species, P. dianthum and P. micranthum. After transition from dark to high light, P. dianthum displayed a rapid re-oxidation of P700, while P. micranthum displayed an over-reduction of P700. Furthermore, the rapid re-oxidation of P700 in P. dianthum was not observed when measured under anaerobic conditions. These results indicated that photo-reduction of O2 mediated by the water-water cycle was functional in P. dianthum but not in P. micranthum. Within the first few seconds after an abrupt transition from low to high light, PSI was highly oxidized in P. dianthum but was highly reduced in P. micranthum, indicating that the different responses of PSI to fluctuating light between P. micranthum and P. dianthum was attributed to the water-water cycle. In P. micranthum, the lack of the water-water cycle was partially compensated for by an enhancement of CEF. Taken together, P. dianthum and P. micranthum employed different strategies to cope with the abrupt change of light intensity, indicating the diversity of strategies for photosynthetic acclimation to fluctuating light in these two closely related orchid species.
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22
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Johnson JE, Berry JA. The role of Cytochrome b 6f in the control of steady-state photosynthesis: a conceptual and quantitative model. PHOTOSYNTHESIS RESEARCH 2021; 148:101-136. [PMID: 33999328 PMCID: PMC8292351 DOI: 10.1007/s11120-021-00840-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 04/26/2021] [Indexed: 05/06/2023]
Abstract
Here, we present a conceptual and quantitative model to describe the role of the Cytochrome [Formula: see text] complex in controlling steady-state electron transport in [Formula: see text] leaves. The model is based on new experimental methods to diagnose the maximum activity of Cyt [Formula: see text] in vivo, and to identify conditions under which photosynthetic control of Cyt [Formula: see text] is active or relaxed. With these approaches, we demonstrate that Cyt [Formula: see text] controls the trade-off between the speed and efficiency of electron transport under limiting light, and functions as a metabolic switch that transfers control to carbon metabolism under saturating light. We also present evidence that the onset of photosynthetic control of Cyt [Formula: see text] occurs within milliseconds of exposure to saturating light, much more quickly than the induction of non-photochemical quenching. We propose that photosynthetic control is the primary means of photoprotection and functions to manage excitation pressure, whereas non-photochemical quenching functions to manage excitation balance. We use these findings to extend the Farquhar et al. (Planta 149:78-90, 1980) model of [Formula: see text] photosynthesis to include a mechanistic description of the electron transport system. This framework relates the light captured by PS I and PS II to the energy and mass fluxes linking the photoacts with Cyt [Formula: see text], the ATP synthase, and Rubisco. It enables quantitative interpretation of pulse-amplitude modulated fluorometry and gas-exchange measurements, providing a new basis for analyzing how the electron transport system coordinates the supply of Fd, NADPH, and ATP with the dynamic demands of carbon metabolism, how efficient use of light is achieved under limiting light, and how photoprotection is achieved under saturating light. The model is designed to support forward as well as inverse applications. It can either be used in a stand-alone mode at the leaf-level or coupled to other models that resolve finer-scale or coarser-scale phenomena.
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Affiliation(s)
- J E Johnson
- Dept. Global Ecology, Carnegie Institution, Stanford, CA, 94305, USA.
| | - J A Berry
- Dept. Global Ecology, Carnegie Institution, Stanford, CA, 94305, USA
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23
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Photosynthetic regulation under fluctuating light at chilling temperature in evergreen and deciduous tree species. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2021; 219:112203. [PMID: 33957467 DOI: 10.1016/j.jphotobiol.2021.112203] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 04/19/2021] [Accepted: 04/25/2021] [Indexed: 11/20/2022]
Abstract
Plants usually experience fluctuating light conditions at chilling temperatures during the autumn season. We hypothesized that photosystem I (PSI) and PSII are more susceptible to photoinhibition under fluctuating light at chilling temperatures in deciduous species relative to evergreen species. We measured the photosynthetic performances under fluctuating light at 6 °C in two evergreen and two deciduous broadleaf tree species. Within the first 10 s after light increased at 6 °C, none of these species could generate an enough trans-thylakoid proton gradient. Meanwhile, PSI was highly oxidised in evergreen species but was highly reduced in deciduous species. This transient over-reduction of PSI in deciduous species was mainly caused by the higher electron flow from PSII. Furthermore, the deciduous species showed a significantly smaller violaxanthin pool and lower non-photochemical quenching under high light conditions at 6 °C, leading to more excess light energy could not be dissipated in PSII. Hence, we propose that fluctuating light combined with chilling temperature cause the over-reduction of photosynthetic electron chain in deciduous species.
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24
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Coordination of Cyclic Electron Flow and Water-Water Cycle Facilitates Photoprotection under Fluctuating Light and Temperature Stress in the Epiphytic Orchid Dendrobium officinale. PLANTS 2021; 10:plants10030606. [PMID: 33806869 PMCID: PMC8004707 DOI: 10.3390/plants10030606] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/13/2021] [Accepted: 03/13/2021] [Indexed: 02/08/2023]
Abstract
Photosystem I (PSI) is the primary target of photoinhibition under fluctuating light (FL). Photosynthetic organisms employ alternative electron flows to protect PSI under FL. However, the understanding of the coordination of alternative electron flows under FL at temperature stresses is limited. To address this question, we measured the chlorophyll fluorescence, P700 redox state, and electrochromic shift signal in leaves of Dendrobium officinale exposed to FL at 42 °C, 25 °C, and 4 °C. Upon a sudden increase in illumination at 42 °C and 25 °C, the water-water cycle (WWC) consumed a significant fraction of the extra reducing power, and thus avoided an over-reduction of PSI. However, WWC was inactivated at 4 °C, leading to an over-reduction of PSI within the first seconds after light increased. Therefore, the role of WWC under FL is largely dependent on temperature conditions. After an abrupt increase in light intensity, cyclic electron flow (CEF) around PSI was stimulated at any temperature. Therefore, CEF and WWC showed different temperature responses under FL. Furthermore, the enhancement of CEF and WWC at 42 °C quickly generated a sufficient trans-thylakoid proton gradient (ΔpH). The inactivation of WWC at 4 °C was partially compensated for by an increased CEF activity. These findings indicate that CEF and WWC coordinate to protect PSI under FL at temperature stresses.
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Sarewicz M, Pintscher S, Pietras R, Borek A, Bujnowicz Ł, Hanke G, Cramer WA, Finazzi G, Osyczka A. Catalytic Reactions and Energy Conservation in the Cytochrome bc1 and b6f Complexes of Energy-Transducing Membranes. Chem Rev 2021; 121:2020-2108. [PMID: 33464892 PMCID: PMC7908018 DOI: 10.1021/acs.chemrev.0c00712] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Indexed: 12/16/2022]
Abstract
This review focuses on key components of respiratory and photosynthetic energy-transduction systems: the cytochrome bc1 and b6f (Cytbc1/b6f) membranous multisubunit homodimeric complexes. These remarkable molecular machines catalyze electron transfer from membranous quinones to water-soluble electron carriers (such as cytochromes c or plastocyanin), coupling electron flow to proton translocation across the energy-transducing membrane and contributing to the generation of a transmembrane electrochemical potential gradient, which powers cellular metabolism in the majority of living organisms. Cytsbc1/b6f share many similarities but also have significant differences. While decades of research have provided extensive knowledge on these enzymes, several important aspects of their molecular mechanisms remain to be elucidated. We summarize a broad range of structural, mechanistic, and physiological aspects required for function of Cytbc1/b6f, combining textbook fundamentals with new intriguing concepts that have emerged from more recent studies. The discussion covers but is not limited to (i) mechanisms of energy-conserving bifurcation of electron pathway and energy-wasting superoxide generation at the quinol oxidation site, (ii) the mechanism by which semiquinone is stabilized at the quinone reduction site, (iii) interactions with substrates and specific inhibitors, (iv) intermonomer electron transfer and the role of a dimeric complex, and (v) higher levels of organization and regulation that involve Cytsbc1/b6f. In addressing these topics, we point out existing uncertainties and controversies, which, as suggested, will drive further research in this field.
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Affiliation(s)
- Marcin Sarewicz
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Sebastian Pintscher
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Rafał Pietras
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Arkadiusz Borek
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Łukasz Bujnowicz
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Guy Hanke
- School
of Biological and Chemical Sciences, Queen
Mary University of London, London E1 4NS, U.K.
| | - William A. Cramer
- Department
of Biological Sciences, Purdue University, West Lafayette, Indiana 47907 United States
| | - Giovanni Finazzi
- Laboratoire
de Physiologie Cellulaire et Végétale, Université Grenoble Alpes, Centre National Recherche Scientifique,
Commissariat Energie Atomique et Energies Alternatives, Institut National
Recherche l’agriculture, l’alimentation et l’environnement, 38054 Grenoble Cedex 9, France
| | - Artur Osyczka
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
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Schmierer M, Brueck H, Asch F, Sauerborn J. Estimating the quantum requirements for plant growth and related electricity demand for LED lighting systems. J Verbrauch Lebensm 2021. [DOI: 10.1007/s00003-021-01314-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
AbstractIndoor plant production systems with artificial lighting are considered an emerging technology contributing to biomass-based value webs. The viability of this concept greatly relies on the energy requirements (ER, Watt) for lighting. We estimated the ER for plant growth by calculating the conversion efficiency of electricity to light of solid-state light-emitting diodes (LED) and the quantum requirements for plant growth of a fictional plant stand producing 2500 g of dry weight per m2 of ground during 100 days, representing a high productivity benchmark of field crops. The quantum output (µmol s−1 W−1) of eight LEDs of different colours varied between 0.78 for green and 2.54 for deep red. Uncertainty in the H+ demand for ATP synthesis during photosynthesis, the relative portion of photorespiration and the fraction of light intercepted by plant canopies (fabs) were considered in a pessimistic (PA) and optimistic (OA) approach of calculation of ER. Cumulative ER were 606 and 265 kWh m−2 for the PA and OA scenarios. The energy conversion efficiencies in the PA and OA scenarios were 2.07 and 4.72%. Estimates of energy savings by suppressing photorespiration and increasing fabs vary between 24 and 38%. The peak daily ER were 9.44 and 4.14 kWh in the PA and OA scenarios. Results are discussed in the context of the design of lighting in indoor plant production systems and commercial greenhouses where natural fluctuation in solar radiation could be balanced by dimmable LED panels.
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27
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Malone LA, Proctor MS, Hitchcock A, Hunter CN, Johnson MP. Cytochrome b 6f - Orchestrator of photosynthetic electron transfer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148380. [PMID: 33460588 DOI: 10.1016/j.bbabio.2021.148380] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 01/06/2021] [Accepted: 01/09/2021] [Indexed: 11/18/2022]
Abstract
Cytochrome b6f (cytb6f) lies at the heart of the light-dependent reactions of oxygenic photosynthesis, where it serves as a link between photosystem II (PSII) and photosystem I (PSI) through the oxidation and reduction of the electron carriers plastoquinol (PQH2) and plastocyanin (Pc). A mechanism of electron bifurcation, known as the Q-cycle, couples electron transfer to the generation of a transmembrane proton gradient for ATP synthesis. Cytb6f catalyses the rate-limiting step in linear electron transfer (LET), is pivotal for cyclic electron transfer (CET) and plays a key role as a redox-sensing hub involved in the regulation of light-harvesting, electron transfer and photosynthetic gene expression. Together, these characteristics make cytb6f a judicious target for genetic manipulation to enhance photosynthetic yield, a strategy which already shows promise. In this review we will outline the structure and function of cytb6f with a particular focus on new insights provided by the recent high-resolution map of the complex from Spinach.
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Affiliation(s)
- Lorna A Malone
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Matthew S Proctor
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Andrew Hitchcock
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.
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28
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Hepworth C, Wood WHJ, Emrich-Mills TZ, Proctor MS, Casson S, Johnson MP. Dynamic thylakoid stacking and state transitions work synergistically to avoid acceptor-side limitation of photosystem I. NATURE PLANTS 2021. [PMID: 33432159 DOI: 10.1038/s41477-020-00828-823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
TAP38/STN7-dependent (de)phosphorylation of light-harvesting complex II (LHCII) regulates the relative excitation rates of photosystems I and II (PSI, PSII) (state transitions) and the size of the thylakoid grana stacks (dynamic thylakoid stacking). Yet, it remains unclear how changing grana size benefits photosynthesis and whether these two regulatory mechanisms function independently. Here, by comparing Arabidopsis wild-type, stn7 and tap38 plants with the psal mutant, which undergoes dynamic thylakoid stacking but lacks state transitions, we explain their distinct roles. Under low light, smaller grana increase the rate of PSI reduction and photosynthesis by reducing the diffusion distance for plastoquinol; however, this beneficial effect is only apparent when PSI/PSII excitation balance is maintained by state transitions or far-red light. Under high light, the larger grana slow plastoquinol diffusion and lower the equilibrium constant between plastocyanin and PSI, maximizing photosynthesis by avoiding PSI photoinhibition. Loss of state transitions in low light or maintenance of smaller grana in high light also both bring about a decrease in cyclic electron transfer and over-reduction of the PSI acceptor side. These results demonstrate that state transitions and dynamic thylakoid stacking work synergistically to regulate photosynthesis in variable light.
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Affiliation(s)
- Christopher Hepworth
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - William H J Wood
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - Tom Z Emrich-Mills
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - Matthew S Proctor
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - Stuart Casson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK.
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29
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Hepworth C, Wood WHJ, Emrich-Mills TZ, Proctor MS, Casson S, Johnson MP. Dynamic thylakoid stacking and state transitions work synergistically to avoid acceptor-side limitation of photosystem I. NATURE PLANTS 2021; 7:87-98. [PMID: 33432159 DOI: 10.1038/s41477-020-00828-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 12/04/2020] [Indexed: 05/11/2023]
Abstract
TAP38/STN7-dependent (de)phosphorylation of light-harvesting complex II (LHCII) regulates the relative excitation rates of photosystems I and II (PSI, PSII) (state transitions) and the size of the thylakoid grana stacks (dynamic thylakoid stacking). Yet, it remains unclear how changing grana size benefits photosynthesis and whether these two regulatory mechanisms function independently. Here, by comparing Arabidopsis wild-type, stn7 and tap38 plants with the psal mutant, which undergoes dynamic thylakoid stacking but lacks state transitions, we explain their distinct roles. Under low light, smaller grana increase the rate of PSI reduction and photosynthesis by reducing the diffusion distance for plastoquinol; however, this beneficial effect is only apparent when PSI/PSII excitation balance is maintained by state transitions or far-red light. Under high light, the larger grana slow plastoquinol diffusion and lower the equilibrium constant between plastocyanin and PSI, maximizing photosynthesis by avoiding PSI photoinhibition. Loss of state transitions in low light or maintenance of smaller grana in high light also both bring about a decrease in cyclic electron transfer and over-reduction of the PSI acceptor side. These results demonstrate that state transitions and dynamic thylakoid stacking work synergistically to regulate photosynthesis in variable light.
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Affiliation(s)
- Christopher Hepworth
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - William H J Wood
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - Tom Z Emrich-Mills
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - Matthew S Proctor
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - Stuart Casson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK.
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30
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Theune ML, Hildebrandt S, Steffen-Heins A, Bilger W, Gutekunst K, Appel J. In-vivo quantification of electron flow through photosystem I - Cyclic electron transport makes up about 35% in a cyanobacterium. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148353. [PMID: 33346012 DOI: 10.1016/j.bbabio.2020.148353] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/23/2020] [Accepted: 12/08/2020] [Indexed: 12/15/2022]
Abstract
Photosynthetic electron flow, driven by photosystem I and II, provides chemical energy for carbon fixation. In addition to a linear mode a second cyclic route exists, which only involves photosystem I. The exact contributions of linear and cyclic transport are still a matter of debate. Here, we describe the development of a method that allows quantification of electron flow in absolute terms through photosystem I in a photosynthetic organism for the first time. Specific in-vivo protocols allowed to discern the redox states of plastocyanin, P700 and the FeS-clusters including ferredoxin at the acceptor site of PSI in the cyanobacterium Synechocystis sp. PCC 6803 with the near-infrared spectrometer Dual-KLAS/NIR. P700 absorbance changes determined with the Dual-KLAS/NIR correlated linearly with direct determinations of PSI concentrations using EPR. Dark-interval relaxation kinetics measurements (DIRKPSI) were applied to determine electron flow through PSI. Counting electrons from hydrogen oxidation as electron donor to photosystem I in parallel to DIRKPSI measurements confirmed the validity of the method. Electron flow determination by classical PSI yield measurements overestimates electron flow at low light intensities and saturates earlier compared to DIRKPSI. Combination of DIRKPSI with oxygen evolution measurements yielded a proportion of 35% of surplus electrons passing PSI compared to PSII. We attribute these electrons to cyclic electron transport, which is twice as high as assumed for plants. Counting electrons flowing through the photosystems allowed determination of the number of quanta required for photosynthesis to 11 per oxygen produced, which is close to published values.
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Affiliation(s)
- Marius L Theune
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Sarah Hildebrandt
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Anja Steffen-Heins
- Division of Food Technology, Institute of Human Nutrition and Food Science, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Wolfgang Bilger
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Kirstin Gutekunst
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Jens Appel
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany.
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31
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Miller NT, Vaughn MD, Burnap RL. Electron flow through NDH-1 complexes is the major driver of cyclic electron flow-dependent proton pumping in cyanobacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148354. [PMID: 33338488 DOI: 10.1016/j.bbabio.2020.148354] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/03/2020] [Accepted: 12/08/2020] [Indexed: 01/12/2023]
Abstract
Cyclic electron flow (CEF) around photosystem I is vital to balancing the photosynthetic energy budget of cyanobacteria and other photosynthetic organisms. The coupling of CEF to proton pumping has long been hypothesized to occur, providing proton motive force (PMF) for the synthesis of ATP with no net cost to [NADPH]. This is thought to occur largely through the activity of NDH-1 complexes, of which cyanobacteria have four with different activities. While a much work has been done to understand the steady-state PMF in both the light and dark, and fluorescent probes have been developed to observe these fluxes in vivo, little has been done to understand the kinetics of these fluxes, particularly with regard to NDH-1 complexes. To monitor the kinetics of proton pumping in Synechocystis sp. PCC 6803, the pH sensitive dye Acridine Orange was used alongside a suite of inhibitors in order to observe light-dependent proton pumping. The assay was demonstrated to measure photosynthetically driven proton pumping and used to measure the rates of proton pumping unimpeded by dark ΔpH. Here, the cyanobacterial NDH-1 complexes are shown to pump a sizable portion of proton flux when CEF-driven and LEF-driven proton pumping rates are observed and compared in mutants lacking some or all NDH-1 complexes. It is also demonstrated that PSII and LEF are responsible for the bulk of light induced proton pumping, though CEF and NDH-1 are capable of generating ~40% of the proton pumping rate when LEF is inactivated.
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Affiliation(s)
- Neil T Miller
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA
| | - Michael D Vaughn
- SpectroLogix LLC, 9050 Executive Park Drive, Knoxville, TN 37923, USA
| | - Robert L Burnap
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA.
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32
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Fu L, Govindjee G, Tan J, Guo Y. Development of a minimized model structure and a feedback control framework for regulating photosynthetic activities. PHOTOSYNTHESIS RESEARCH 2020; 146:213-225. [PMID: 31813097 DOI: 10.1007/s11120-019-00690-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 11/04/2019] [Indexed: 06/10/2023]
Abstract
In this work, the main activities of the plant photosynthesis process are discussed to yield a minimized mathematical model structure with photosystem II (PSII) chlorophyll a fluorescence (ChlF) as a measurable output. After experimental validation of the model structure, we demonstrate that the states of the photosynthetic process may be observed by using this model and the extended Kalman filter method. We then show a feedback control framework that can be used to alter a given photosynthetic activity. The control framework is demonstrated with an example in which PSII ChlF is used as the feedback signal and light intensity is used as a controllable process input to regulate plastoquinone reduction. Although there are caveats, and further research is needed, the results lay the groundwork for further research on novel methods for optimization and regulation of photosynthetic activities, with a goal for sustainability.
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Affiliation(s)
- Lijiang Fu
- Key Laboratory of Advanced Process Control for Light Industry (Ministry of Education), Jiangnan University, Wuxi, 214122, China
| | - Govindjee Govindjee
- Department of Biochemistry, Department of Plant Biology, and Center of Biophysics & Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
| | - Jinglu Tan
- University of Missouri, Columbia, MO, 65211, USA
| | - Ya Guo
- Key Laboratory of Advanced Process Control for Light Industry (Ministry of Education), Jiangnan University, Wuxi, 214122, China.
- University of Missouri, Columbia, MO, 65211, USA.
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33
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Laughlin TG, Savage DF, Davies KM. Recent advances on the structure and function of NDH-1: The complex I of oxygenic photosynthesis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148254. [PMID: 32645407 DOI: 10.1016/j.bbabio.2020.148254] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/07/2020] [Accepted: 06/22/2020] [Indexed: 12/29/2022]
Abstract
Photosynthetic NADH dehydrogenase-like complex type-1 (a.k.a, NDH, NDH-1, or NDH-1L) is a multi-subunit, membrane-bound oxidoreductase related to the respiratory complex I. Although originally discovered 30 years ago, a number of recent advances have revealed significant insight into the structure, function, and physiology of NDH-1. Here, we highlight progress in understanding the function of NDH-1 in the photosynthetic light reactions of both cyanobacteria and chloroplasts from biochemical and structural perspectives. We further examine the cyanobacterial-specific forms of NDH-1 that possess vectorial carbonic anhydrase (vCA) activity and function in the CO2-concentrating mechanism (CCM). We compare the proposed mechanism for the cyanobacterial NDH-1 vCA-activity to that of the DAB (DABs accumulates bicarbonate) complex, another putative vCA. Finally, we discuss both new and remaining questions pertaining to the mechanisms of NDH-1 complexes in light of these recent advances.
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Affiliation(s)
- Thomas G Laughlin
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA; Molecular Biophysics and Integrative Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - David F Savage
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Karen M Davies
- Molecular Biophysics and Integrative Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA; Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
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34
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Pleban JR, Guadagno CR, Mackay DS, Weinig C, Ewers BE. Rapid Chlorophyll a Fluorescence Light Response Curves Mechanistically Inform Photosynthesis Modeling. PLANT PHYSIOLOGY 2020; 183:602-619. [PMID: 32152213 PMCID: PMC7271808 DOI: 10.1104/pp.19.00375] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 02/18/2020] [Indexed: 05/08/2023]
Abstract
Crop improvement is crucial to ensuring global food security under climate change, and hence there is a pressing need for phenotypic observations that are both high throughput and improve mechanistic understanding of plant responses to environmental cues and limitations. In this study, chlorophyll a fluorescence light response curves and gas-exchange observations are combined to test the photosynthetic response to moderate drought in four genotypes of Brassica rapa The quantum yield of PSII (ϕ PSII ) is here analyzed as an exponential decline under changing light intensity and soil moisture. Both the maximum ϕ PSII and the rate of ϕ PSII decline across a large range of light intensities (0-1,000 μmol photons m-2 s-1; β PSII ) are negatively affected by drought. We introduce an alternative photosynthesis model (β PSII model) incorporating parameters from rapid fluorescence response curves. Specifically, the model uses β PSII as an input for estimating the photosynthetic electron transport rate, which agrees well with two existing photosynthesis models (Farquhar-von Caemmerer-Berry and Yin). The β PSII model represents a major improvement in photosynthesis modeling through the integration of high-throughput fluorescence phenotyping data, resulting in gained parameters of high mechanistic value.
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Affiliation(s)
- Jonathan R Pleban
- Department of Geography, State University of New York, Buffalo, New York 14260
| | | | - David S Mackay
- Department of Geography, State University of New York, Buffalo, New York 14260
| | - Cynthia Weinig
- Department of Botany, University of Wyoming, Laramie, Wyoming 82071
- Program in Ecology, University of Wyoming, Laramie, Wyoming 82071
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071
| | - Brent E Ewers
- Department of Botany, University of Wyoming, Laramie, Wyoming 82071
- Program in Ecology, University of Wyoming, Laramie, Wyoming 82071
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35
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Tan SL, Yang YJ, Huang W. Moderate heat stress accelerates photoinhibition of photosystem I under fluctuating light in tobacco young leaves. PHOTOSYNTHESIS RESEARCH 2020; 144:373-382. [PMID: 32333230 DOI: 10.1007/s11120-020-00754-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 04/19/2020] [Indexed: 06/11/2023]
Abstract
Moderate heat stress and fluctuating light are typical conditions in summer in tropical and subtropical regions. This type of stress can cause photodamage to photosystems I and II (PSI and PSII). However, photosynthetic responses to the combination of heat and fluctuating light in young leaves are little known. In this study, we investigated chlorophyll fluorescence and P700 redox state under fluctuating light at 25 °C and 42 °C in young leaves of tobacco. Our results indicated that fluctuating light caused selective photodamage to PSI in the young leaves at 25 °C and 42 °C. Furthermore, the moderate heat stress significantly accelerated photoinhibition of PSI under fluctuating light. Within the first 10 s after transition from low to high light, cyclic electron flow (CEF) around PSI was highly stimulated at 25 °C but was slightly activated at 42 °C. Such depression of CEF activation at moderate heat stress were unable to maintain energy balance under high light. As a result, electron flow from PSI to NADP+ was restricted, leading to the over-reduction of PSI electron carriers. These results indicated that moderate heat stress altered the CEF performance under fluctuating light and thus accelerated PSI photoinhibition in tobacco young leaves.
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Affiliation(s)
- Shun-Ling Tan
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ying-Jie Yang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
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36
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Sun H, Yang YJ, Huang W. The water-water cycle is more effective in regulating redox state of photosystem I under fluctuating light than cyclic electron transport. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148235. [PMID: 32485160 DOI: 10.1016/j.bbabio.2020.148235] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/12/2020] [Accepted: 05/26/2020] [Indexed: 11/28/2022]
Abstract
Photosynthetic electron flux from water via photosystem II (PSII) and PSI to oxygen (water-water cycle) may act as an alternative electron sink under fluctuating light in angiosperms. We measured the P700 redox kinetics and electrochromic shift signal under fluctuating light in 11 Camellia species and tobacco leaves. Upon dark-to-light transition, these Camellia species showed rapid re-oxidation of P700. However, this rapid re-oxidation of P700 was not observed when measured under anaerobic conditions, as was in experiment with tobacco performed under aerobic conditions. Therefore, photo-reduction of O2 mediated by water-water cycle was functional in these Camellia species but not in tobacco. Within the first 10 s after transition from low to high light, PSI was highly oxidized in these Camellia species but was over-reduced in tobacco leaves. Furthermore, such rapid oxidation of PSI in these Camellia species was independent of the formation of trans-thylakoid proton gradient (ΔpH). These results indicated that in addition to ΔpH-dependent photosynthetic control, the water-water cycle can protect PSI against photoinhibition under fluctuating light in these Camellia species. We here propose that the water-water cycle is an overlooked strategy for photosynthetic regulation under fluctuating light in angiosperms.
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Affiliation(s)
- Hu Sun
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ying-Jie Yang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Huang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China.
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Sela A, Piskurewicz U, Megies C, Mène-Saffrané L, Finazzi G, Lopez-Molina L. Embryonic Photosynthesis Affects Post-Germination Plant Growth. PLANT PHYSIOLOGY 2020; 182:2166-2181. [PMID: 32060052 PMCID: PMC7140907 DOI: 10.1104/pp.20.00043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 01/28/2020] [Indexed: 05/02/2023]
Abstract
Photosynthesis is the fundamental process fueling plant vegetative growth and development. The progeny of plants relies on maternal photosynthesis, via food reserves in the seed, to supply the necessary energy for seed germination and early seedling establishment. Intriguingly, before seed maturation, Arabidopsis (Arabidopsis thaliana) embryos are also photosynthetically active, the biological significance of which remains poorly understood. Investigating this system is genetically challenging because mutations perturbing photosynthesis are expected to affect both embryonic and vegetative tissues. Here, we isolated a temperature-sensitive mutation affecting CPN60α2, which encodes a subunit of the chloroplast chaperonin complex CPN60. When exposed to cold temperatures, cpn60α2 mutants accumulate less chlorophyll in newly produced tissues, thus allowing the specific disturbance of embryonic photosynthesis. Analyses of cpn60α2 mutants were combined with independent genetic and pharmacological approaches to show that embryonic photosynthetic activity is necessary for normal skoto- and photomorphogenesis in juvenile seedlings as well as long-term adult plant development. Our results reveal the importance of embryonic photosynthetic activity for normal adult plant growth, development, and health.
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Affiliation(s)
- Ayala Sela
- Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland
| | - Urszula Piskurewicz
- Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland
| | - Christian Megies
- Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland
| | | | - Giovanni Finazzi
- Université Grenoble Alpes, Centre National de la Recherche Scientifique, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Institut National de la Recherche Agronomique, Interdisciplinary Research Institute of Grenoble - Cell & Plant Physiology Laboratory, 38000 Grenoble, France
| | - Luis Lopez-Molina
- Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland
- Institute of Genetics and Genomics in Geneva, University of Geneva, 1211 Geneva, Switzerland
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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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Yang YJ, Zhang SB, Wang JH, Huang W. The decline in photosynthetic rate upon transfer from high to low light is linked to the slow kinetics of chloroplast ATP synthase in Bletilla striata. PHOTOSYNTHESIS RESEARCH 2020; 144:13-21. [PMID: 32166520 DOI: 10.1007/s11120-020-00725-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 02/12/2020] [Indexed: 06/10/2023]
Abstract
Upon a sudden transition from high to low light, the rate of CO2 assimilation (AN) in some plants first decreases to a low level before gradually becoming stable. However, the underlying mechanisms remain controversial. The activity of chloroplast ATP synthase (gH+) is usually depressed under high light when compared with low light. Therefore, we hypothesize that upon a sudden transfer from high to low light, the relatively low gH+ restricts ATP synthesis and thus causes a reduction in AN. To test this hypothesis, we measured gas exchange, chlorophyll fluorescence, P700 redox state, and electrochromic shift signals in Bletilla striata (Orchidaceae). After the transition from saturating to lower irradiance, AN and ETRII decreased first to a low level and then gradually increased to a stable value. Within the first seconds after transfer from high to low light, gH+ was maintained at low levels. During further exposure to low light, gH+ gradually increased to a stable value. Interestingly, a tight positive relationship was found between gH+ and ETRII. These results suggested that upon a sudden transition from high to low light, AN was restricted by gH+ at the step of ATP synthesis. Taken together, we propose that the decline in AN upon sudden transfer from high to low light is linked to the slow kinetics of chloroplast ATP synthase.
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Affiliation(s)
- Ying-Jie Yang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shi-Bao Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Ji-Hua Wang
- Yunnan Academy of Agricultural Sciences, Kunming, 650205, Yunnan, China.
| | - Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
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Tan SL, Yang YJ, Liu T, Zhang SB, Huang W. Responses of photosystem I compared with photosystem II to combination of heat stress and fluctuating light in tobacco leaves. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2020; 292:110371. [PMID: 32005377 DOI: 10.1016/j.plantsci.2019.110371] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/02/2019] [Accepted: 12/07/2019] [Indexed: 05/02/2023]
Abstract
Moderate heat stress is usually accompanied with fluctuating light in summer. Although either heat stress or fluctuating light can cause photoinhibition of photosystems I and II (PSI and PSII), it is unclear whether moderate heat stress accelerate photoinhibition under fluctuating light. Here, we measured chlorophyll fluorescence, P700 redox state and the electrochromic shift signal under fluctuating light at 25 °C and 42 °C for tobacco leaves. We found that (1) the thylakoid proton conductance was significantly enhanced at 42 °C, leading to a decline in trans-thylakoid proton gradient (ΔpH); (2) this low ΔpH at 42 °C did not decrease donor-side limitation of PSI and thermal energy dissipation in PSII; (3) the activation of cyclic electron flow (CEF) around PSI was elevated at 42 °C; and (4) the moderate heat stress did not accelerate photoinhibition of PSI and PSII under fluctuating light. These results strongly indicate that under moderate heat stress the stimulation of CEF protects PSI under fluctuating light in tobacco leaves.
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Affiliation(s)
- Shun-Ling Tan
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ying-Jie Yang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Tao Liu
- National Local Joint Engineering Research Center on Germplasm Utilization and Innovation of Chinese Medicinal Materials in Southwest China, Yunnan Agricultural University, Kunming, 650201, China
| | - Shi-Bao Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
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Kono M, Kawaguchi H, Mizusawa N, Yamori W, Suzuki Y, Terashima I. Far-Red Light Accelerates Photosynthesis in the Low-Light Phases of Fluctuating Light. PLANT & CELL PHYSIOLOGY 2020; 61:192-202. [PMID: 31617558 DOI: 10.1093/pcp/pcz191] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 09/26/2019] [Indexed: 05/09/2023]
Abstract
It is well known that far-red light (FR; >700 nm) drives PSI photochemistry, but its effect on photosynthetic performance has received little attention. In this study, the effects of the addition of FR to red fluctuating light (FL) have on photosynthesis were examined in the leaves of Arabidopsis thaliana. Light-activated leaves were illuminated with FL [alternating high light/low light (HL/LL) at 800/30 μmol m-2 s-1] for 10-15 min without or with FR at intensities that reflected natural conditions. The CO2 assimilation rates upon the transition from HL to LL were significantly greater with FR than without FR. The enhancement of photosynthesis by FR was small under the steady-state conditions and in the HL phases of FL. Proton conductivity through the thylakoid membrane (gH+) in the LL phases of FL, estimated from the dark relaxation kinetics of the electrochromic absorbance shift, was greater with FR than without FR. The relaxation of non-photochemical quenching (NPQ) in the PSII antenna system and the increase in PSII photochemistry in the LL phases accelerated in the presence of FR. Similar FR-effects in FL were confirmed in typical sun and shade plants. On the basis of these results, we concluded that FR exerted beneficial effects on photosynthesis in FL by exciting PSI and accelerating NPQ relaxation and PSII-yield increase. This was probably because of the increased gH+, which would reflect faster ΔpH dissipation and ATP synthesis.
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Affiliation(s)
- Masaru Kono
- Department of Biological Sciences, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
| | - Hikaru Kawaguchi
- Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa, 259-1293 Japan
| | - Naoki Mizusawa
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, 184-8584 Japan
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo, 184-0003 Japan
| | - Wataru Yamori
- Department of Biological Sciences, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
| | - Yoshihiro Suzuki
- Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa, 259-1293 Japan
| | - Ichiro Terashima
- Department of Biological Sciences, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
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42
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Toyoshima M, Toya Y, Shimizu H. Flux balance analysis of cyanobacteria reveals selective use of photosynthetic electron transport components under different spectral light conditions. PHOTOSYNTHESIS RESEARCH 2020; 143:31-43. [PMID: 31625072 DOI: 10.1007/s11120-019-00678-x] [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: 05/21/2019] [Accepted: 10/01/2019] [Indexed: 05/05/2023]
Abstract
Cyanobacteria acclimate and adapt to changing light conditions by controlling the energy transfer between photosystem I (PSI) and II (PSII) and pigment composition. Photosynthesis is driven by balancing the excitation between PSI and PSII. To predict the detailed electron transfer flux of cyanobacteria, we refined the photosynthesis-related reactions in our previously reconstructed genome-scale model. Two photosynthetic bacteria, Arthrospira and Synechocystis, were used as models. They were grown under various spectral light conditions and flux balance analysis (FBA) was performed using photon uptake fluxes into PSI and PSII, which were converted from each light spectrum by considering the photoacclimation of pigments and the distribution ratio of phycobilisome to PSI and PSII. In Arthrospira, the FBA was verified with experimental data using six types of light-emitting diodes (White, Blue, Green, Yellow, Red1, and Red2). FBA predicted the cell growth of Synechocystis for the LEDs, excepting Red2. In an FBA simulation, cells used respiratory terminal oxidases and two NADH dehydrogenases (NDH-1 and NDH-2) to balance the PSI and PSII excitations depending on the light conditions. FBA simulation with our refined model functionally implicated NDH-1 and NDH-2 as a component of cyclic electron transport in the varied light environments.
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Affiliation(s)
- Masakazu Toyoshima
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yoshihiro Toya
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hiroshi Shimizu
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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43
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Sun H, Zhang SB, Liu T, Huang W. Decreased photosystem II activity facilitates acclimation to fluctuating light in the understory plant Paris polyphylla. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1861:148135. [PMID: 31821793 DOI: 10.1016/j.bbabio.2019.148135] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 11/22/2019] [Accepted: 12/04/2019] [Indexed: 01/11/2023]
Abstract
In forests, understory plants are usually exposed to sunflecks on timescales of seconds or minutes. However, it is unclear how understory plants acclimate to fluctuating light. In this study, we compared chlorophyll fluorescence, PSI redox state and the electrochromic shift signal under fluctuating light between an understory plant Paris polyphylla (Liliaceae) and a light-demanding plant Bletilla striata (Orchidaceae). Within the first seconds after transition from low to high light, PSI was highly oxidized in P. polyphylla but was highly reduced in B. striata, although both species could not generate a sufficient trans-thylakoid proton gradient (ΔpH). Furthermore, the outflow of electrons from PSI to O2 was not significant in P. polyphylla, as indicated by the P700 redox kinetics upon dark-to-light transition. Therefore, the different responses of PSI to fluctuating light between P. polyphylla and B. striata could not be explained by ΔpH formation or alternative electron transport. In contrast, upon a sudden transition from low to high light, electron flow from PSII was much lower in P. polyphylla than in B. striata, suggesting that the rapid oxidation of PSI in P. polyphylla was largely attributed to the lower PSII activity. We propose, for the first time, that down-regulation of PSII activity is an important strategy used by some understory angiosperms to cope with sunflecks.
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Affiliation(s)
- Hu Sun
- Kunming Institute of Botany, Chinese Academy of Sciences, 650201 Kunming, China; University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Shi-Bao Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, 650201 Kunming, China
| | - Tao Liu
- National Local Joint Engineering Research Center on Germplasm Utilization and Innovation of Chinese Medicinal Materials in Southwest China, Yunnan Agricultural University, 650201 Kunming, China.
| | - Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, 650201 Kunming, China.
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Huang W, Yang YJ, Wang JH, Hu H. Photorespiration is the major alternative electron sink under high light in alpine evergreen sclerophyllous Rhododendron species. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 289:110275. [PMID: 31623777 DOI: 10.1016/j.plantsci.2019.110275] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 08/08/2019] [Accepted: 09/13/2019] [Indexed: 06/10/2023]
Abstract
Owing to the high leaf mass per area, alpine evergreen sclerophyllous Rhododendron have low values of mesophyll conductance (gm). The resulting low chloroplast CO2 concentration aggravates photorespiration, which requires a higher ATP/NADPH ratio. However, the significance of photorespiration and underlying mechanisms of energy balance in these species are little known. In this study, eight alpine evergreen sclerophyllous Rhododendron species grown in a common garden were tested for their gm, electron flow to photorespiration, and energy balancing. Under saturating light, gm was the most limiting factor for net photosynthesis (AN) in all species, and the species differences in AN were primarily driven by gm rather than stomatal conductance. The total electron flow through photosystem II (ETRII) nearly equaled the electron transport required for Rubisco carboxylation and oxygenation. Furthermore, blocking electron flow to photosystem I with appropriate inhibitors showed that electron flow to plastic terminal oxidase was not observed. As a result, these studied species showed little alternative electron flow mediated by water-water cycle or plastic terminal oxidase. By comparison, the ratio of electron transport consumed by photorespiration to ETRII (JPR/ETRII), ranging from 43%∼55%, was negatively correlated to AN and gm. Furthermore, the increased ATP production required by enhanced photorespiration was regulated by cyclic electron flow around photosystem I. These results indicate that photorespiration is the major electron sink for dissipation of excess excitation energy in the alpine evergreen sclerophyllous Rhododendron species. The coordination of gm, photorespiration and cyclic electron flow is important for sustaining leaf photosynthesis.
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Affiliation(s)
- Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, PR China
| | - Ying-Jie Yang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Ji-Hua Wang
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, Kunming, Yunnan, PR China.
| | - Hong Hu
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, PR China.
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Harada K, Arizono T, Sato R, Trinh MDL, Hashimoto A, Kono M, Tsujii M, Uozumi N, Takaichi S, Masuda S. DAY-LENGTH-DEPENDENT DELAYED-GREENING1, the Arabidopsis Homolog of the Cyanobacterial H+-Extrusion Protein, Is Essential for Chloroplast pH Regulation and Optimization of Non-Photochemical Quenching. PLANT & CELL PHYSIOLOGY 2019; 60:2660-2671. [PMID: 31665522 DOI: 10.1093/pcp/pcz203] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 10/22/2019] [Indexed: 05/21/2023]
Abstract
Plants convert solar energy into chemical energy through photosynthesis, which supports almost all life activities on earth. Because the intensity and quality of sunlight can change dramatically throughout the day, various regulatory mechanisms help plants adjust their photosynthetic output accordingly, including the regulation of light energy accumulation to prevent the generation of damaging reactive oxygen species. Non-photochemical quenching (NPQ) is a regulatory mechanism that dissipates excess light energy, but how it is regulated is not fully elucidated. In this study, we report a new NPQ-regulatory protein named Day-Length-dependent Delayed-Greening1 (DLDG1). The Arabidopsis DLDG1 associates with the chloroplast envelope membrane, and the dldg1 mutant had a large NPQ value compared with wild type. The mutant also had a pale-green phenotype in developing leaves but only under continuous light; this phenotype was not observed when dldg1 was cultured in the dark for ≥8 h/d. DLDG1 is a homolog of the plasma membrane-localizing cyanobacterial proton-extrusion-protein A that is required for light-induced H+ extrusion and also shows similarity in its amino-acid sequence to that of Ycf10 encoded in the plastid genome. Arabidopsis DLDG1 enhances the growth-retardation phenotype of the Escherichia coli K+/H+ antiporter mutant, and the everted membrane vesicles of the E. coli expressing DLDG1 show the K+/H+ antiport activity. Our findings suggest that DLDG1 functionally interacts with Ycf10 to control H+ homeostasis in chloroplasts, which is important for the light-acclimation response, by optimizing the extent of NPQ.
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Affiliation(s)
- Kyohei Harada
- School of Life Science & Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
| | - Takatoshi Arizono
- School of Life Science & Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
| | - Ryoichi Sato
- School of Life Science & Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
| | - Mai Duy Luu Trinh
- School of Life Science & Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
| | - Akira Hashimoto
- School of Life Science & Technology, 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
| | - Masaru Tsujii
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai, 980-8579 Japan
| | - Nobuyuki Uozumi
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai, 980-8579 Japan
| | - Shinichi Takaichi
- Department of Molecular Microbiology, Faculty of Life Science, Tokyo University of Agriculture, Tokyo, 156-8502 Japan
| | - Shinji Masuda
- School of Life Science & Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
- Center for Biological Resources & Informatics, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
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46
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Harada K, Arizono T, Sato R, Trinh MDL, Hashimoto A, Kono M, Tsujii M, Uozumi N, Takaichi S, Masuda S. DAY-LENGTH-DEPENDENT DELAYED-GREENING1, the Arabidopsis Homolog of the Cyanobacterial H+-Extrusion Protein, Is Essential for Chloroplast pH Regulation and Optimization of Non-Photochemical Quenching. PLANT & CELL PHYSIOLOGY 2019; 60:2660-2671. [PMID: 31665522 DOI: 10.1101/731653] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 10/22/2019] [Indexed: 05/24/2023]
Abstract
Plants convert solar energy into chemical energy through photosynthesis, which supports almost all life activities on earth. Because the intensity and quality of sunlight can change dramatically throughout the day, various regulatory mechanisms help plants adjust their photosynthetic output accordingly, including the regulation of light energy accumulation to prevent the generation of damaging reactive oxygen species. Non-photochemical quenching (NPQ) is a regulatory mechanism that dissipates excess light energy, but how it is regulated is not fully elucidated. In this study, we report a new NPQ-regulatory protein named Day-Length-dependent Delayed-Greening1 (DLDG1). The Arabidopsis DLDG1 associates with the chloroplast envelope membrane, and the dldg1 mutant had a large NPQ value compared with wild type. The mutant also had a pale-green phenotype in developing leaves but only under continuous light; this phenotype was not observed when dldg1 was cultured in the dark for ≥8 h/d. DLDG1 is a homolog of the plasma membrane-localizing cyanobacterial proton-extrusion-protein A that is required for light-induced H+ extrusion and also shows similarity in its amino-acid sequence to that of Ycf10 encoded in the plastid genome. Arabidopsis DLDG1 enhances the growth-retardation phenotype of the Escherichia coli K+/H+ antiporter mutant, and the everted membrane vesicles of the E. coli expressing DLDG1 show the K+/H+ antiport activity. Our findings suggest that DLDG1 functionally interacts with Ycf10 to control H+ homeostasis in chloroplasts, which is important for the light-acclimation response, by optimizing the extent of NPQ.
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Affiliation(s)
- Kyohei Harada
- School of Life Science & Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
| | - Takatoshi Arizono
- School of Life Science & Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
| | - Ryoichi Sato
- School of Life Science & Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
| | - Mai Duy Luu Trinh
- School of Life Science & Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
| | - Akira Hashimoto
- School of Life Science & Technology, 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
| | - Masaru Tsujii
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai, 980-8579 Japan
| | - Nobuyuki Uozumi
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai, 980-8579 Japan
| | - Shinichi Takaichi
- Department of Molecular Microbiology, Faculty of Life Science, Tokyo University of Agriculture, Tokyo, 156-8502 Japan
| | - Shinji Masuda
- School of Life Science & Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
- Center for Biological Resources & Informatics, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
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47
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Probing the electric field across thylakoid membranes in cyanobacteria. Proc Natl Acad Sci U S A 2019; 116:21900-21906. [PMID: 31591197 DOI: 10.1073/pnas.1913099116] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In plants, algae, and some photosynthetic bacteria, the ElectroChromic Shift (ECS) of photosynthetic pigments, which senses the electric field across photosynthetic membranes, is widely used to quantify the activity of the photosynthetic chain. In cyanobacteria, ECS signals have never been used for physiological studies, although they can provide a unique tool to study the architecture and function of the respiratory and photosynthetic electron transfer chains, entangled in the thylakoid membranes. Here, we identified bona fide ECS signals, likely corresponding to carotenoid band shifts, in the model cyanobacteria Synechococcus elongatus PCC7942 and Synechocystis sp. PCC6803. These band shifts, most likely originating from pigments located in photosystem I, have highly similar spectra in the 2 species and can be best measured as the difference between the absorption changes at 500 to 505 nm and the ones at 480 to 485 nm. These signals respond linearly to the electric field and display the basic kinetic features of ECS as characterized in other organisms. We demonstrate that these probes are an ideal tool to study photosynthetic physiology in vivo, e.g., the fraction of PSI centers that are prebound by plastocyanin/cytochrome c 6 in darkness (about 60% in both cyanobacteria, in our experiments), the conductivity of the thylakoid membrane (largely reflecting the activity of the ATP synthase), or the steady-state rates of the photosynthetic electron transport pathways.
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Yang YJ, Ding XX, Huang W. Stimulation of cyclic electron flow around photosystem I upon a sudden transition from low to high light in two angiosperms Arabidopsis thaliana and Bletilla striata. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 287:110166. [PMID: 31481226 DOI: 10.1016/j.plantsci.2019.110166] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 05/20/2019] [Accepted: 06/06/2019] [Indexed: 06/10/2023]
Abstract
In angiosperms, cyclic electron flow (CEF) around photosystem I (PSI) is more important for photoprotection under fluctuating light than under constant light. However, the underlying mechanism is not well known. In the present study, we measured the CEF activity, P700 redox state and electrochromic shift signal upon a sudden transition from low to high light in wild-type plants of Arabidopsis thaliana and Bletilla striata (Orchidaceae). Within the first 20 s after transition from low to high light, P700 was highly reduced in both species, which was accompanied with a sufficient proton gradient (ΔpH) across the thylakoid membranes. Meanwhile, the level of CEF activation was elevated. After transition from low to high light for 60 s, the plants generated an optimal ΔpH. Under such condition, PSI was highly oxidized and the level of CEF activation decreased to the steady state. Furthermore, the CEF activation was positively correlated to the P700 reduction ratio. These results indicated that upon a sudden transition from low to high light, the insufficient ΔpH led to the over-reduction of PSI electron carriers, which in turn stimulated the CEF around PSI. This transient stimulation of CEF not only favored the rapid ΔpH formation but also accepted electrons from PSI, thus protecting PSI at donor and acceptor sides. These findings provide new insights into the important role of CEF in regulation of photosynthesis under fluctuating light.
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Affiliation(s)
- Ying-Jie Yang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiao-Xi Ding
- Kunming Forest Resources Administration, Kunming, China
| | - Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China.
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49
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Yang YJ, Zhang SB, Wang JH, Huang W. Photosynthetic regulation under fluctuating light in field-grown Cerasus cerasoides: A comparison of young and mature leaves. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:148073. [PMID: 31473302 DOI: 10.1016/j.bbabio.2019.148073] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/22/2019] [Accepted: 08/27/2019] [Indexed: 11/15/2022]
Abstract
Photosystem I (PSI) is a potential target of photoinhibition under fluctuating light. However, photosynthetic regulation under fluctuating light in field-grown plants is little known. Furthermore, it is unclear how young leaves protect PSI against fluctuating light under natural field conditions. In the present study, we examined chlorophyll fluorescence, P700 redox state and the electrochromic shift signal in the young and mature leaves of field-grown Cerasus cerasoides (Rosaceae). Within the first seconds after any increase in light intensity, young leaves showed higher proton gradient (ΔpH) across the thylakoid membranes than the mature leaves, preventing over-reduction of PSI in the young leaves. As a result, PSI was more tolerant to fluctuating light in the young leaves than in the mature leaves. Interestingly, after transition from low to high light, the activity of cyclic electron flow (CEF) in young leaves increased first to a high level and then decreased to a stable value, while this rapid stimulation of CEF was not observed in the mature leaves. Furthermore, the over-reduction of PSI significantly stimulated CEF in the young leaves but not in the mature leaves. Taken together, within the first seconds after any increase in illumination, the stimulation of CEF favors the rapid lumen acidification and optimizes the PSI redox state in the young leaves, protecting PSI against photoinhibition under fluctuating light in field-grown plants.
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Affiliation(s)
- Ying-Jie Yang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shi-Bao Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - Ji-Hua Wang
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, Kunming, Yunnan, China.
| | - Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China.
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50
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Berepiki A, Gittins JR, Moore CM, Bibby TS. Rational engineering of photosynthetic electron flux enhances light-powered cytochrome P450 activity. Synth Biol (Oxf) 2018; 3:ysy009. [PMID: 32995517 PMCID: PMC7445785 DOI: 10.1093/synbio/ysy009] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 05/04/2018] [Accepted: 05/25/2018] [Indexed: 11/21/2022] Open
Abstract
In this study, we exploited a modified photosynthetic electron transfer chain (PET) in the model cyanobacterium Synechococcus PCC 7002, where electrons derived from water-splitting are used to power reactions catalyzed by a heterologous cytochrome P450 (CYP1A1). A simple in vivo fluorescent assay for CYP1A1 activity was employed to determine the impact of rationally engineering of photosynthetic electron flow. This showed that knocking out a subunit of the type I NADH dehydrogenase complex (NDH-1), suggested to be involved in cyclic photosynthetic electron flow (ΔndhD2), can double the activity of CYP1A1, with a concomitant increase in the flux of electrons from photosynthesis. This also resulted in an increase in cellular adenosine triphosphate (ATP) and the ATP/nicotinamide adenine dinucleotide phosphate (NADPH) ratio, suggesting that expression of a heterologous electron sink in photosynthetic organisms can be used to modify the bioenergetic landscape of the cell. We therefore demonstrate that CYP1A1 is limited by electron supply and that photosynthesis can be re-engineered to increase heterologous P450 activity for the production of high-value bioproducts. The increase in cellular ATP achieved could be harnessed to support metabolically demanding heterologous processes. Furthermore, this experimental system could provide valuable insights into the mechanisms of photosynthesis.
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Affiliation(s)
- Adokiye Berepiki
- Ocean and Earth Science, University of Southampton, Waterfront Campus, National Oceanography Centre, Southampton SO14 3ZH, UK.,Manchester Institute of Biotechnology, University of Manchester, Princess St, Manchester M1 7DN, UK
| | - John R Gittins
- Ocean and Earth Science, University of Southampton, Waterfront Campus, National Oceanography Centre, Southampton SO14 3ZH, UK
| | - C Mark Moore
- Ocean and Earth Science, University of Southampton, Waterfront Campus, National Oceanography Centre, Southampton SO14 3ZH, UK
| | - Thomas S Bibby
- Ocean and Earth Science, University of Southampton, Waterfront Campus, National Oceanography Centre, Southampton SO14 3ZH, UK
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