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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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2
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Rashkov GD, Stefanov MA, Yotsova EK, Borisova PB, Dobrikova AG, Apostolova EL. Exploring Nitric Oxide as a Regulator in Salt Tolerance: Insights into Photosynthetic Efficiency in Maize. PLANTS (BASEL, SWITZERLAND) 2024; 13:1312. [PMID: 38794383 PMCID: PMC11125177 DOI: 10.3390/plants13101312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 04/29/2024] [Accepted: 05/08/2024] [Indexed: 05/26/2024]
Abstract
The growing issue of salinity is a significant threat to global agriculture, affecting diverse regions worldwide. Nitric oxide (NO) serves as an essential signal molecule in regulating photosynthetic performance under physiological and stress conditions. The present study reveals the protective effects of different concentrations (0-300 µM) of sodium nitroprusside (SNP, a donor of NO) on the functions of the main complexes within the photosynthetic apparatus of maize (Zea mays L. Kerala) under salt stress (150 mM NaCl). The data showed that SNP alleviates salt-induced oxidative stress and prevents changes in the fluidity of thylakoid membranes (Laurdan GP) and energy redistribution between the two photosystems (77K chlorophyll fluorescence ratio F735/F685). Chlorophyll fluorescence measurements demonstrated that the foliar spray with SNP under salt stress prevents the decline of photosystem II (PSII) open reaction centers (qP) and improves their efficiency (Φexc), thereby influencing QA- reoxidation. The data also revealed that SNP protects the rate constants for two pathways of QA- reoxidation (k1 and k2) from the changes caused by NaCl treatment alone. Additionally, there is a predominance of QA- interaction with plastoquinone in comparison to the recombination of electrons in QA QB- with the oxygen-evolving complex (OEC). The analysis of flash oxygen evolution showed that SNP treatment prevents a salt-induced 10% increase in PSII centers in the S0 state, i.e., protects the initial S0-S1 state distribution, and the modification of the Mn cluster in the OEC. Moreover, this study demonstrates that SNP-induced defense occurs on both the donor and acceptor sides of the PSII, leading to the protection of overall photosystems performance (PIABS) and efficient electron transfer from the PSII donor side to the reduction of PSI end electron acceptors (PItotal). This study clearly shows that the optimal protection under salt stress occurs at approximately 50-63 nmoles NO/g FW in leaves, corresponding to foliar spray with 50-150 µM SNP.
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Affiliation(s)
| | | | | | | | | | - Emilia L. Apostolova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria; (G.D.R.); (M.A.S.); (E.K.Y.); (P.B.B.); (A.G.D.)
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3
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Stefanov MA, Rashkov GD, Borisova PB, Apostolova EL. Changes in Photosystem II Complex and Physiological Activities in Pea and Maize Plants in Response to Salt Stress. PLANTS (BASEL, SWITZERLAND) 2024; 13:1025. [PMID: 38611554 PMCID: PMC11013719 DOI: 10.3390/plants13071025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 03/26/2024] [Accepted: 04/01/2024] [Indexed: 04/14/2024]
Abstract
Salt stress significantly impacts the functions of the photosynthetic apparatus, with varying degrees of damage to its components. Photosystem II (PSII) is more sensitive to environmental stresses, including salinity, than photosystem I (PSI). This study investigated the effects of different salinity levels (0 to 200 mM NaCl) on the PSII complex in isolated thylakoid membranes from hydroponically grown pea (Pisum sativum L.) and maize (Zea mays L.) plants treated with NaCl for 5 days. The data revealed that salt stress inhibits the photochemical activity of PSII (H2O → BQ), affecting the energy transfer between the pigment-protein complexes of PSII (as indicated by the fluorescence emission ratio F695/F685), QA reoxidation, and the function of the oxygen-evolving complex (OEC). These processes were more significantly affected in pea than in maize under salinity. Analysis of the oxygen evolution curves after flashes and continuous illumination showed a stronger influence on the PSIIα than PSIIβ centers. The inhibition of oxygen evolution was associated with an increase in misses (α), double hits (β), and blocked centers (SB) and a decrease in the rate constant of turnover of PSII reaction centers (KD). Salinity had different effects on the two pathways of QA reoxidation in maize and pea. In maize, the electron flow from QA- to plastoquinone was dominant after treatment with higher NaCl concentrations (150 mM and 200 mM), while in pea, the electron recombination on QAQB- with oxidized S2 (or S3) of the OEC was more pronounced. Analysis of the 77 K fluorescence emission spectra revealed changes in the ratio of the light-harvesting complex of PSII (LHCII) monomers and trimers to LHCII aggregates after salt treatment. There was also a decrease in pigment composition and an increase in oxidative stress markers, membrane injury index, antioxidant activity (FRAP assay), and antiradical activity (DPPH assay). These effects were more pronounced in pea than in maize after treatment with higher NaCl concentrations (150 mM-200 mM). This study provides insights into how salinity influences the processes in the donor and acceptor sides of PSII in plants with different salt sensitivity.
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Affiliation(s)
- Martin A Stefanov
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria
| | - Georgi D Rashkov
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria
| | - Preslava B Borisova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria
| | - Emilia L Apostolova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria
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Shi T, Fan D, Xu C, Zheng G, Zhong C, Feng F, Chow WS. The Fitting of the OJ Phase of Chlorophyll Fluorescence Induction Based on an Analytical Solution and Its Application in Urban Heat Island Research. PLANTS (BASEL, SWITZERLAND) 2024; 13:452. [PMID: 38337985 PMCID: PMC10857409 DOI: 10.3390/plants13030452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 01/28/2024] [Accepted: 02/01/2024] [Indexed: 02/12/2024]
Abstract
Chlorophyll (Chl) fluorescence induction (FI) upon a dark-light transition has been widely analyzed to derive information on initial events of energy conversion and electron transfer in photosystem II (PSII). However, currently, there is no analytical solution to the differential equation of QA reduction kinetics, raising a doubt about the fitting of FI by numerical iteration solution. We derived an analytical solution to fit the OJ phase of FI, thereby yielding estimates of three parameters: the functional absorption cross-section of PSII (σPSII), a probability parameter that describes the connectivity among PSII complexes (p), and the rate coefficient for QA- oxidation (kox). We found that σPSII, p, and kox exhibited dynamic changes during the transition from O to J. We postulated that in high excitation light, some other energy dissipation pathways may vastly outcompete against excitation energy transfer from a closed PSII trap to an open PSII, thereby giving the impression that connectivity seemingly does not exist. We also conducted a case study on the urban heat island effect on the heat stability of PSII using our method and showed that higher-temperature-acclimated leaves had a greater σPSII, lower kox, and a tendency of lower p towards more shade-type characteristics.
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Affiliation(s)
- Tongxin Shi
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing 100083, China; (T.S.)
| | - Dayong Fan
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing 100083, China; (T.S.)
| | - Chengyang Xu
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing 100083, China; (T.S.)
| | - Guoming Zheng
- Yi Zong Qi Technology (Beijing) Co., Ltd., Beijing 100095, China
| | - Chuanfei Zhong
- Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100093, China
| | - Fei Feng
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing 100083, China; (T.S.)
| | - Wah Soon Chow
- Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
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Driever SM. Measurement of Photorespiratory Oxygen Exchange by Membrane Inlet Mass Spectrometry. Methods Mol Biol 2024; 2792:163-173. [PMID: 38861086 DOI: 10.1007/978-1-0716-3802-6_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
Photosynthesis and metabolism in plants involve oxygen as both a product and substrate. Oxygen is taken up during photorespiration and respiration and produced through water splitting during photosynthesis. To distinguish between processes that produce or consume O2 in leaves, isotope mass separation and detection by mass spectrometry allows measurement of evolution and uptake of O2 as well as CO2 uptake. This chapter describes how to calculate the rate of Rubisco oxygenation and carboxylation from in vivo gas exchange of stable isotopes of 16O2 and 18O2 with a closed cuvette system for leaf discs and membrane inlet mass spectrometry.
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Affiliation(s)
- Steven M Driever
- Centre for Crop System Analysis, Wageningen University and Research, Wageningen, The Netherlands.
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6
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Driever SM. Measurement of O 2 Uptake and Evolution in Leaves In Vivo Using Stable Isotopes and Membrane Inlet Mass Spectrometry. Methods Mol Biol 2024; 2790:149-162. [PMID: 38649571 DOI: 10.1007/978-1-0716-3790-6_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Oxygen is both product and substrate of photosynthesis and metabolism in plants, by oxygen evolution through water splitting and uptake by photorespiration and respiration. It is important to investigate these processes simultaneously in leaves, especially in response to environmental variables, such as light and temperature. To distinguish between processes that evolve or take up O2 in leaves in the light, in vivo gas exchange of stable isotopes of oxygen and membrane inlet mass spectrometry is used. A closed-cuvette system for gas exchange of leaf discs is described, using the stable isotopes 16O2 and 18O2, with a semi-permeable membrane gas inlet and isotope mass separation and detection by mass spectrometry. Measurement of evolution and uptake, as well as CO2 uptake, at a range of light levels allows composition of a light response curve, here described for French bean (Phaseolus vulgaris) and maize (Zea mays) leaf discs.
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Affiliation(s)
- Steven M Driever
- Centre for Crop System Analysis, Wageningen University, Wageningen, The Netherlands.
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Rashkov GD, Stefanov MA, Yotsova EK, Borisova PB, Dobrikova AG, Apostolova EL. Impact of Sodium Nitroprusside on the Photosynthetic Performance of Maize and Sorghum. PLANTS (BASEL, SWITZERLAND) 2023; 13:118. [PMID: 38202426 PMCID: PMC10781006 DOI: 10.3390/plants13010118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 12/26/2023] [Accepted: 12/29/2023] [Indexed: 01/12/2024]
Abstract
Nitric oxide (NO) is an important molecule in regulating plant growth, development and photosynthetic performance. This study investigates the impact of varying concentrations (0-300 µM) of sodium nitroprusside (SNP, a donor of NO) on the functions of the photosynthetic apparatus in sorghum (Sorghum bicolor L. Albanus) and maize (Zea mays L. Kerala) under physiological conditions. Analysis of the chlorophyll fluorescence signals (using PAM and the JIP-test) revealed an increased amount of open PSII reaction centers (qP increased), but it did not affect the number of active reaction centers per PSII antenna chlorophyll (RC/ABS). In addition, the smaller SNP concentrations (up to 150 μM) alleviated the interaction of QA with plastoquine in maize, while at 300 μM it predominates the electron recombination on QAQB-, with the oxidized S2 (or S3) states of oxygen evolving in complex ways in both studied plant species. At the same time, SNP application stimulated the electron flux-reducing end electron acceptors at the PSI acceptor side per reaction center (REo/RC increased up to 26%) and the probability of their reduction (φRo increased up to 20%). An increase in MDA (by about 30%) and H2O2 contents was registered only at the highest SNP concentration (300 µM). At this concentration, SNP differentially affected the amount of P700+ in studied plant species, i.e., it increased (by 10%) in maize but decreased (by 16%) in sorghum. The effects of SNP on the functions of the photosynthetic apparatus were accompanied by an increase in carotenoid content in both studied plants. Additionally, data revealed that SNP-induced changes in the photosynthetic apparatus differed between maize and sorghum, suggesting species specificity for SNP's impact on plants.
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Affiliation(s)
| | | | | | | | | | - Emilia L. Apostolova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria; (G.D.R.); (M.A.S.); (E.K.Y.); (P.B.B.); (A.G.D.)
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8
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Bag P, Shutova T, Shevela D, Lihavainen J, Nanda S, Ivanov AG, Messinger J, Jansson S. Flavodiiron-mediated O 2 photoreduction at photosystem I acceptor-side provides photoprotection to conifer thylakoids in early spring. Nat Commun 2023; 14:3210. [PMID: 37270605 DOI: 10.1038/s41467-023-38938-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 05/23/2023] [Indexed: 06/05/2023] Open
Abstract
Green organisms evolve oxygen (O2) via photosynthesis and consume it by respiration. Generally, net O2 consumption only becomes dominant when photosynthesis is suppressed at night. Here, we show that green thylakoid membranes of Scots pine (Pinus sylvestris L) and Norway spruce (Picea abies) needles display strong O2 consumption even in the presence of light when extremely low temperatures coincide with high solar irradiation during early spring (ES). By employing different electron transport chain inhibitors, we show that this unusual light-induced O2 consumption occurs around photosystem (PS) I and correlates with higher abundance of flavodiiron (Flv) A protein in ES thylakoids. With P700 absorption changes, we demonstrate that electron scavenging from the acceptor-side of PSI via O2 photoreduction is a major alternative pathway in ES. This photoprotection mechanism in vascular plants indicates that conifers have developed an adaptative evolution trajectory for growing in harsh environments.
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Affiliation(s)
- Pushan Bag
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
- Section of Molecular Plant Biology, Department of Biology, University of Oxford, Oxford, UK
| | - Tatyana Shutova
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Dmitry Shevela
- Department of Chemistry, Chemical Biological Centre, Umeå University, Umeå, Sweden
| | - Jenna Lihavainen
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Sanchali Nanda
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Alexander G Ivanov
- Department of Biology, University of Western Ontario, London, ON, Canada
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Johannes Messinger
- Department of Chemistry, Chemical Biological Centre, Umeå University, Umeå, Sweden
- Department of Chemistry-Ångström laboratory, Uppsala University, Uppsala, Sweden
| | - Stefan Jansson
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden.
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Gu L, Grodzinski B, Han J, Marie T, Zhang Y, Song YC, Sun Y. Granal thylakoid structure and function: explaining an enduring mystery of higher plants. THE NEW PHYTOLOGIST 2022; 236:319-329. [PMID: 35832001 PMCID: PMC9805053 DOI: 10.1111/nph.18371] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 07/07/2022] [Indexed: 05/11/2023]
Abstract
In higher plants, photosystems II and I are found in grana stacks and unstacked stroma lamellae, respectively. To connect them, electron carriers negotiate tortuous multi-media paths and are subject to macromolecular blocking. Why does evolution select an apparently unnecessary, inefficient bipartition? Here we systematically explain this perplexing phenomenon. We propose that grana stacks, acting like bellows in accordions, increase the degree of ultrastructural control on photosynthesis through thylakoid swelling/shrinking induced by osmotic water fluxes. This control coordinates with variations in stomatal conductance and the turgor of guard cells, which act like an accordion's air button. Thylakoid ultrastructural dynamics regulate macromolecular blocking/collision probability, direct diffusional pathlengths, division of function of Cytochrome b6 f complex between linear and cyclic electron transport, luminal pH via osmotic water fluxes, and the separation of pH dynamics between granal and lamellar lumens in response to environmental variations. With the two functionally asymmetrical photosystems located distantly from each other, the ultrastructural control, nonphotochemical quenching, and carbon-reaction feedbacks maximally cooperate to balance electron transport with gas exchange, provide homeostasis in fluctuating light environments, and protect photosystems in drought. Grana stacks represent a dry/high irradiance adaptation of photosynthetic machinery to improve fitness in challenging land environments. Our theory unifies many well-known but seemingly unconnected phenomena of thylakoid structure and function in higher plants.
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Affiliation(s)
- Lianhong Gu
- Environmental Sciences Division and Climate Change Science InstituteOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Bernard Grodzinski
- Department of Plant AgricultureUniversity of GuelphGuelphONN1G 2W1Canada
| | - Jimei Han
- School of Integrative Plant ScienceCornell UniversityIthacaNY14853USA
| | - Telesphore Marie
- Department of Plant AgricultureUniversity of GuelphGuelphONN1G 2W1Canada
| | | | - Yang C. Song
- Department of Hydrology and Atmospheric SciencesUniversity of ArizonaTucsonAZ85721USA
| | - Ying Sun
- School of Integrative Plant ScienceCornell UniversityIthacaNY14853USA
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Stefanov MA, Rashkov GD, Apostolova EL. Assessment of the Photosynthetic Apparatus Functions by Chlorophyll Fluorescence and P 700 Absorbance in C3 and C4 Plants under Physiological Conditions and under Salt Stress. Int J Mol Sci 2022; 23:3768. [PMID: 35409126 PMCID: PMC8998893 DOI: 10.3390/ijms23073768] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/26/2022] [Accepted: 03/27/2022] [Indexed: 11/18/2022] Open
Abstract
Functions of the photosynthetic apparatus of C3 (Pisum sativum L.) and C4 (Zea mays L.) plants under physiological conditions and after treatment with different NaCl concentrations (0-200 mM) were investigated using chlorophyll a fluorescence (pulse-amplitude-modulated (PAM) and JIP test) and P700 photooxidation measurement. Data revealed lower density of the photosynthetic structures (RC/CSo), larger relative size of the plastoquinone (PQ) pool (N) and higher electron transport capacity and photosynthetic rate (parameter RFd) in C4 than in C3 plants. Furthermore, the differences were observed between the two studied species in the parameters characterizing the possibility of reduction in the photosystem (PSI) end acceptors (REo/RC, REo/CSo and δRo). Data revealed that NaCl treatment caused a decrease in the density of the photosynthetic structures and relative size of the PQ pool as well as decrease in the electron transport to the PSI end electron acceptors and the probability of their reduction as well as an increase in the thermal dissipation. The effects were stronger in pea than in maize. The enhanced energy losses after high salt treatment in maize were mainly from the increase in the regulated energy losses (ΦNPQ), while in pea from the increase in non-regulated energy losses (ΦNO). The reduction in the electron transport from QA to the PSI end electron acceptors influenced PSI activity. Analysis of the P700 photooxidation and its decay kinetics revealed an influence of two PSI populations in pea after treatment with 150 mM and 200 mM NaCl, while in maize the negligible changes were registered only at 200 mM NaCl. The experimental results clearly show less salt tolerance of pea than maize.
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Affiliation(s)
| | | | - Emilia L. Apostolova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria; (M.A.S.); (G.D.R.)
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11
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Yang YJ, Shi Q, Sun H, Mei RQ, Huang W. Differential Response of the Photosynthetic Machinery to Fluctuating Light in Mature and Young Leaves of Dendrobium officinale. FRONTIERS IN PLANT SCIENCE 2022; 12:829783. [PMID: 35185969 PMCID: PMC8850366 DOI: 10.3389/fpls.2021.829783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
A key component of photosynthetic electron transport chain, photosystem I (PSI), is susceptible to the fluctuating light (FL) in angiosperms. Cyclic electron flow (CEF) around PSI and water-water cycle (WWC) are both used by the epiphytic orchid Dendrobium officinale to protect PSI under FL. This study examined whether the ontogenetic stage of leaf has an impact on the photoprotective mechanisms dealing with FL. Thus, chlorophyll fluorescence and P700 signals under FL were measured in D. officinale young and mature leaves. Upon transition from dark to actinic light, a rapid re-oxidation of P700 was observed in mature leaves but disappeared in young leaves, indicating that WWC existed in mature leaves but was lacking in young leaves. After shifting from low to high light, PSI over-reduction was clearly missing in mature leaves. By comparison, young leaves showed a transient PSI over-reduction within the first 30 s, which was accompanied with highly activation of CEF. Therefore, the effect of FL on PSI redox state depends on the leaf ontogenetic stage. In mature leaves, WWC is employed to avoid PSI over-reduction. In young leaves, CEF around PSI is enhanced to compensate for the lack of WWC and thus to prevent an uncontrolled PSI over-reduction induced by FL.
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Affiliation(s)
- Ying-Jie Yang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Qi Shi
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Hu Sun
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ren-Qiang Mei
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- Bio-Innovation Center of DR PLANT, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
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12
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Diurnal Response of Photosystem I to Fluctuating Light Is Affected by Stomatal Conductance. Cells 2021; 10:cells10113128. [PMID: 34831351 PMCID: PMC8621556 DOI: 10.3390/cells10113128] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/26/2021] [Accepted: 10/27/2021] [Indexed: 11/17/2022] Open
Abstract
Upon a sudden transition from low to high light, electrons transported from photosystem II (PSII) to PSI should be rapidly consumed by downstream sinks to avoid the over-reduction of PSI. However, the over-reduction of PSI under fluctuating light might be accelerated if primary metabolism is restricted by low stomatal conductance. To test this hypothesis, we measured the effect of diurnal changes in stomatal conductance on photosynthetic regulation under fluctuating light in tomato (Solanum lycopersicum) and common mulberry (Morus alba). Under conditions of high stomatal conductance, we observed PSI over-reduction within the first 10 s after transition from low to high light. Lower stomatal conductance limited the activity of the Calvin–Benson–Bassham cycle and aggravated PSI over-reduction within 10 s after the light transition. We also observed PSI over-reduction after transition from low to high light for 30 s at the low stomatal conductance typical of the late afternoon, indicating that low stomatal conductance extends the period of PSI over-reduction under fluctuating light. Therefore, diurnal changes in stomatal conductance significantly affect the PSI redox state under fluctuating light. Moreover, our analysis revealed an unexpected inhibition of cyclic electron flow by the severe over-reduction of PSI seen at low stomatal conductance. In conclusion, stomatal conductance can have a large effect on thylakoid reactions under fluctuating light.
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Zendonadi Dos Santos N, Piepho HP, Condorelli GE, Licieri Groli E, Newcomb M, Ward R, Tuberosa R, Maccaferri M, Fiorani F, Rascher U, Muller O. High-throughput field phenotyping reveals genetic variation in photosynthetic traits in durum wheat under drought. PLANT, CELL & ENVIRONMENT 2021; 44:2858-2878. [PMID: 34189744 DOI: 10.1111/pce.14136] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 04/14/2021] [Accepted: 06/13/2021] [Indexed: 06/13/2023]
Abstract
Chlorophyll fluorescence (ChlF) is a powerful non-invasive technique for probing photosynthesis. Although proposed as a method for drought tolerance screening, ChlF has not yet been fully adopted in physiological breeding, mainly due to limitations in high-throughput field phenotyping capabilities. The light-induced fluorescence transient (LIFT) sensor has recently been shown to reliably provide active ChlF data for rapid and remote characterisation of plant photosynthetic performance. We used the LIFT sensor to quantify photosynthesis traits across time in a large panel of durum wheat genotypes subjected to a progressive drought in replicated field trials over two growing seasons. The photosynthetic performance was measured at the canopy level by means of the operating efficiency of Photosystem II ( Fq'/Fm' ) and the kinetics of electron transport measured by reoxidation rates ( Fr1' and Fr2' ). Short- and long-term changes in ChlF traits were found in response to soil water availability and due to interactions with weather fluctuations. In mild drought, Fq'/Fm' and Fr2' were little affected, while Fr1' was consistently accelerated in water-limited compared to well-watered plants, increasingly so with rising vapour pressure deficit. This high-throughput approach allowed assessment of the native genetic diversity in ChlF traits while considering the diurnal dynamics of photosynthesis.
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Affiliation(s)
| | - Hans-Peter Piepho
- Biostatistics Unit, Institute of Crop Science, University of Hohenheim, Stuttgart, Germany
| | | | - Eder Licieri Groli
- Department of Agricultural and Food Sciences, University of Bologna, Bologna, Italy
| | - Maria Newcomb
- Maricopa Agricultural Center, University of Arizona, Maricopa, Arizona, USA
| | - Richard Ward
- Maricopa Agricultural Center, University of Arizona, Maricopa, Arizona, USA
| | - Roberto Tuberosa
- Department of Agricultural and Food Sciences, University of Bologna, Bologna, Italy
| | - Marco Maccaferri
- Department of Agricultural and Food Sciences, University of Bologna, Bologna, Italy
| | - Fabio Fiorani
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Uwe Rascher
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Onno Muller
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, Jülich, Germany
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14
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Phua SY, De Smet B, Remacle C, Chan KX, Van Breusegem F. Reactive oxygen species and organellar signaling. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:5807-5824. [PMID: 34009340 DOI: 10.1093/jxb/erab218] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 05/14/2021] [Indexed: 05/07/2023]
Abstract
The evolution of photosynthesis and its associated metabolic pathways has been crucial to the successful establishment of plants, but has also challenged plant cells in the form of production of reactive oxygen species (ROS). Intriguingly, multiple forms of ROS are generated in virtually every plant cell compartment through diverse pathways. As a result, a sophisticated network of ROS detoxification and signaling that is simultaneously tailored to individual organelles and safeguards the entire cell is necessary. Here we take an organelle-centric view on the principal sources and sinks of ROS across the plant cell and provide insights into the ROS-induced organelle to nucleus retrograde signaling pathways needed for operational readjustments during environmental stresses.
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Affiliation(s)
- Su Yin Phua
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent,Belgium
- Center for Plant Systems Biology, VIB, Ghent,Belgium
| | - Barbara De Smet
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent,Belgium
- Center for Plant Systems Biology, VIB, Ghent,Belgium
| | - Claire Remacle
- Genetics and Physiology of Microalgae, InBios/Phytosystems, Université de Liège, Liège,Belgium
| | - Kai Xun Chan
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent,Belgium
- Center for Plant Systems Biology, VIB, Ghent,Belgium
| | - Frank Van Breusegem
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent,Belgium
- Center for Plant Systems Biology, VIB, Ghent,Belgium
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15
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Kameoka T, Okayasu T, Kikuraku K, Ogawa T, Sawa Y, Yamamoto H, Ishikawa T, Maruta T. Cooperation of chloroplast ascorbate peroxidases and proton gradient regulation 5 is critical for protecting Arabidopsis plants from photo-oxidative stress. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:876-892. [PMID: 34028907 DOI: 10.1111/tpj.15352] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 05/14/2021] [Accepted: 05/18/2021] [Indexed: 05/24/2023]
Abstract
High-light (HL) stress enhances the production of H2 O2 from the photosynthetic electron transport chain in chloroplasts, potentially causing photo-oxidative damage. Although stromal and thylakoid membrane-bound ascorbate peroxidases (sAPX and tAPX, respectively) are major H2 O2 -scavenging enzymes in chloroplasts, their knockout mutants do not exhibit a visible phenotype under HL stress. Trans-thylakoid proton gradient (∆pH)-dependent mechanisms exist for controlling H2 O2 production from photosynthesis, such as thermal dissipation of light energy and downregulation of electron transfer between photosystems II and I, and these may compensate for the lack of APXs. To test this hypothesis, we focused on a proton gradient regulation 5 (pgr5) mutant, wherein both ∆pH-dependent mechanisms are impaired, and an Arabidopsis sapx tapx double mutant was crossed with the pgr5 single mutant. The sapx tapx pgr5 triple mutant exhibited extreme sensitivity to HL compared with its parental lines. This phenotype was consistent with cellular redox perturbations and enhanced expression of many oxidative stress-responsive genes. These findings demonstrate that the PGR5-dependent mechanisms compensate for chloroplast APXs, and vice versa. An intriguing finding was that the failure of induction of non-photochemical quenching in pgr5 (because of the limitation in ∆pH formation) was partially recovered in sapx tapx pgr5. Further genetic studies suggested that this recovery was dependent on the NADH dehydrogenase-like complex-dependent pathway for cyclic electron flow around photosystem I. Together with data from the sapx tapx npq4 mutant, we discuss the interrelationship between APXs and ∆pH-dependent mechanisms under HL stress.
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Affiliation(s)
- Takashi Kameoka
- Graduate School of Natural Science and Technology, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504, Japan
- Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504, Japan
| | - Takaya Okayasu
- Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504, Japan
| | - Kana Kikuraku
- Graduate School of Natural Science and Technology, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504, Japan
- Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504, Japan
- Bioresource and Life Sciences, The United Graduate School of Agricultural Sciences, Tottori University, 4-101 Koyama-Minami, Tottori, Tottori, 680-8553, Japan
| | - Takahisa Ogawa
- Graduate School of Natural Science and Technology, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504, Japan
- Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504, Japan
- Bioresource and Life Sciences, The United Graduate School of Agricultural Sciences, Tottori University, 4-101 Koyama-Minami, Tottori, Tottori, 680-8553, Japan
- Institute of Agricultural and Life Sciences, Academic Assembly, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504, Japan
| | - Yoshihiro Sawa
- Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504, Japan
| | - Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Takahiro Ishikawa
- Graduate School of Natural Science and Technology, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504, Japan
- Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504, Japan
- Bioresource and Life Sciences, The United Graduate School of Agricultural Sciences, Tottori University, 4-101 Koyama-Minami, Tottori, Tottori, 680-8553, Japan
- Institute of Agricultural and Life Sciences, Academic Assembly, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504, Japan
| | - Takanori Maruta
- Graduate School of Natural Science and Technology, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504, Japan
- Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504, Japan
- Bioresource and Life Sciences, The United Graduate School of Agricultural Sciences, Tottori University, 4-101 Koyama-Minami, Tottori, Tottori, 680-8553, Japan
- Institute of Agricultural and Life Sciences, Academic Assembly, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504, Japan
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Sagun JV, Badger MR, Chow WS, Ghannoum O. Mehler reaction plays a role in C 3 and C 4 photosynthesis under shade and low CO 2. PHOTOSYNTHESIS RESEARCH 2021; 149:171-185. [PMID: 33534052 DOI: 10.1007/s11120-021-00819-1] [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: 08/18/2020] [Accepted: 01/09/2021] [Indexed: 06/12/2023]
Abstract
Alternative electron fluxes such as the cyclic electron flux (CEF) around photosystem I (PSI) and Mehler reaction (Me) are essential for efficient photosynthesis because they generate additional ATP and protect both photosystems against photoinhibition. The capacity for Me can be estimated by measuring O2 exchange rate under varying irradiance and CO2 concentration. In this study, mass spectrometric measurements of O2 exchange were made using leaves of representative species of C3 and C4 grasses grown under natural light (control; PAR ~ 800 µmol quanta m-2 s-1) and shade (~ 300 µmol quanta m-2 s-1), and in representative species of gymnosperm, liverwort and fern grown under natural light. For all control grown plants measured at high CO2, O2 uptake rates were similar between the light and dark, and the ratio of Rubisco oxygenation to carboxylation (Vo/Vc) was low, which suggests little potential for Me, and that O2 uptake was mainly due to photorespiration or mitochondrial respiration under these conditions. Low CO2 stimulated O2 uptake in the light, Vo/Vc and Me in all species. The C3 species had similar Vo/Vc, but Me was highest in the grass and lowest in the fern. Among the C4 grasses, shade increased O2 uptake in the light, Vo/Vc and the assimilation quotient (AQ), particularly at low CO2, whilst Me was only substantial at low CO2 where it may contribute 20-50% of maximum electron flow under high light.
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Affiliation(s)
- Julius Ver Sagun
- ARC Centre of Excellence for Translational Photosynthesis, Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Murray R Badger
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Wah Soon Chow
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Oula Ghannoum
- ARC Centre of Excellence for Translational Photosynthesis, Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, Locked Bag 1797, Penrith, NSW, 2751, Australia.
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Leaf Age-Dependent Photosystem II Photochemistry and Oxidative Stress Responses to Drought Stress in Arabidopsis thaliana Are Modulated by Flavonoid Accumulation. Molecules 2021; 26:molecules26144157. [PMID: 34299433 PMCID: PMC8307756 DOI: 10.3390/molecules26144157] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/04/2021] [Accepted: 07/06/2021] [Indexed: 11/17/2022] Open
Abstract
We investigated flavonoid accumulation and lipid peroxidation in young leaves (YL) and mature leaves (ML) of Arabidopsis thaliana plants, whose watering stopped 24 h before sampling, characterized as onset of drought stress (OnDS), six days before sampling, characterized as mild drought stress (MiDS), and ten days before sampling, characterized as moderate drought stress (MoDS). The response to drought stress (DS) of photosystem II (PSII) photochemistry, in both leaf types, was evaluated by estimating the allocation of absorbed light to photochemistry (ΦPSII), to heat dissipation by regulated non-photochemical energy loss (ΦNPQ) and to non-regulated energy dissipated in PSII (ΦNO). Young leaves were better protected at MoDS than ML leaves, by having higher concentration of flavonoids that promote acclimation of YL PSII photochemistry to MoDS, showing lower lipid peroxidation and excitation pressure (1 - qp). Young leaves at MoDS possessed lower 1 - qp values and lower excess excitation energy (EXC), not only compared to MoDS ML, but even to MiDS YL. They also possessed a higher capacity to maintain low ΦNO, suggesting a lower singlet oxygen (1O2) generation. Our results highlight that leaves of different developmental stage may display different responses to DS, due to differential accumulation of metabolites, and imply that PSII photochemistry in Arabidopsis thaliana may not show a dose dependent DS response.
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18
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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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19
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Huang W, Sun H, Tan SL, Zhang SB. The water-water cycle is not a major alternative sink in fluctuating light at chilling temperature. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 305:110828. [PMID: 33691962 DOI: 10.1016/j.plantsci.2021.110828] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 11/30/2020] [Accepted: 01/12/2021] [Indexed: 05/13/2023]
Abstract
The water-water cycle (WWC) has the potential to alleviate photoinhibition of photosystem I (PSI) in fluctuating light (FL) at room temperature and moderate heat stress. However, it is unclear whether WWC can function as a safety valve for PSI in FL at chilling temperature. In this study, we measured P700 redox state and chlorophyll fluorescence in FL at 25 °C and 4 °C in the high WWC activity plant Dendrobium officinale. At 25 °C, the operation of WWC contributed to the rapid re-oxidation of P700 upon dark-to-light transition. However, such rapid re-oxidation of P700 was not observed at 4 °C. Upon a sudden increase in light intensity, WWC rapidly consumed excess electrons in PSI and thus avoided an over-reduction of PSI at 25 °C. On the contrary, PSI was highly reduced within the first seconds after transition from low to high light at 4 °C. Therefore, in opposite to 25 °C, the WWC is not a major alternative sink in FL at chilling temperature. Upon transition from low to high light, cyclic electron transport was highly stimulated at 4 °C when compared with 25 °C. These results indicate that D. officinale enhances cyclic electron transport to partially compensate for the inactivation of WWC in FL at 4 °C.
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Affiliation(s)
- Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; Bio-Innovation Center of DR PLANT, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
| | - Hu Sun
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shun-Ling Tan
- 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
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20
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Slattery RA, Ort DR. Perspectives on improving light distribution and light use efficiency in crop canopies. PLANT PHYSIOLOGY 2021; 185:34-48. [PMID: 33631812 PMCID: PMC8133579 DOI: 10.1093/plphys/kiaa006] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/03/2020] [Indexed: 05/22/2023]
Abstract
Plant stands in nature differ markedly from most seen in modern agriculture. In a dense mixed stand, plants must vie for resources, including light, for greater survival and fitness. Competitive advantages over surrounding plants improve fitness of the individual, thus maintaining the competitive traits in the gene pool. In contrast, monoculture crop production strives to increase output at the stand level and thus benefits from cooperation to increase yield of the community. In choosing plants with higher yields to propagate and grow for food, humans may have inadvertently selected the best competitors rather than the best cooperators. Here, we discuss how this selection for competitiveness has led to overinvestment in characteristics that increase light interception and, consequently, sub-optimal light use efficiency in crop fields that constrains yield improvement. Decades of crop canopy modeling research have provided potential strategies for improving light distribution in crop canopies, and we review the current progress of these strategies, including balancing light distribution through reducing pigment concentration. Based on recent research revealing red-shifted photosynthetic pigments in algae and photosynthetic bacteria, we also discuss potential strategies for optimizing light interception and use through introducing alternative pigment types in crops. These strategies for improving light distribution and expanding the wavelengths of light beyond those traditionally defined for photosynthesis in plant canopies may have large implications for improving crop yield and closing the yield gap.
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Affiliation(s)
- Rebecca A Slattery
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Donald R Ort
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Departments of Plant Biology & Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Author for communication:
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21
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Yang YJ, Tan SL, Sun H, Huang JL, Huang W, Zhang SB. Photosystem I is tolerant to fluctuating light under moderate heat stress in two orchids Dendrobium officinale and Bletilla striata. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 303:110795. [PMID: 33487367 DOI: 10.1016/j.plantsci.2020.110795] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/03/2020] [Accepted: 12/05/2020] [Indexed: 06/12/2023]
Abstract
Under natural field conditions, plants usually experience fluctuating light (FL) under moderate heat stress in summer. However, responses of photosystems I and II (PSI and PSII) to such combined stresses are not well known. Furthermore, the role of water-water cycle (WWC) in photoprotection in FL under moderate heat stress is poorly understood. In this study, we examined chlorophyll fluorescence and P700 redox state in FL at 42 °C in two orchids, Dendrobium officinale (with high WWC activity) and Bletilla striata (with low WWC activity). After FL treatment at 42 °C, PSI activity maintained stable while PSII activity decreased significantly in these two orchids. In D. officinale, the WWC could rapidly consume the excess excitation energy in PSI and thus avoided an over-reduction of PSI upon any increase in illumination. Therefore, in D. officinale, WWC likely protected PSI in FL at 42 °C. In B. striata, heat-induced PSII photoinhibition down-regulated electron flow from PSII and thus prevented an over-reduction of PSI after transition from low to high light. Consequently, in B. striata moderate PSII photoinhibition could protected PSI in FL at 42 °C. We conclude that, in addition to cyclic electron flow, WWC and PSII photoinhibition-repair cycle are two important strategies for preventing PSI photoinhibition in FL under moderate heat stress.
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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
| | - Shun-Ling Tan
- 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
| | - Jia-Lin Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; Bio-Innovation Center of DR PLANT, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
| | - Shi-Bao Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
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22
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Meyer AJ, Dreyer A, Ugalde JM, Feitosa-Araujo E, Dietz KJ, Schwarzländer M. Shifting paradigms and novel players in Cys-based redox regulation and ROS signaling in plants - and where to go next. Biol Chem 2020; 402:399-423. [PMID: 33544501 DOI: 10.1515/hsz-2020-0291] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 11/09/2020] [Indexed: 02/06/2023]
Abstract
Cys-based redox regulation was long regarded a major adjustment mechanism of photosynthesis and metabolism in plants, but in the recent years, its scope has broadened to most fundamental processes of plant life. Drivers of the recent surge in new insights into plant redox regulation have been the availability of the genome-scale information combined with technological advances such as quantitative redox proteomics and in vivo biosensing. Several unexpected findings have started to shift paradigms of redox regulation. Here, we elaborate on a selection of recent advancements, and pinpoint emerging areas and questions of redox biology in plants. We highlight the significance of (1) proactive H2O2 generation, (2) the chloroplast as a unique redox site, (3) specificity in thioredoxin complexity, (4) how to oxidize redox switches, (5) governance principles of the redox network, (6) glutathione peroxidase-like proteins, (7) ferroptosis, (8) oxidative protein folding in the ER for phytohormonal regulation, (9) the apoplast as an unchartered redox frontier, (10) redox regulation of respiration, (11) redox transitions in seed germination and (12) the mitochondria as potential new players in reductive stress safeguarding. Our emerging understanding in plants may serve as a blueprint to scrutinize principles of reactive oxygen and Cys-based redox regulation across organisms.
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Affiliation(s)
- Andreas J Meyer
- Chemical Signalling, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Friedrich-Ebert-Allee 144, D-53113Bonn, Germany
| | - Anna Dreyer
- Biochemistry and Physiology of Plants, Faculty of Biology, W5-134, Bielefeld University, University Street 25, D-33501Bielefeld, Germany
| | - José M Ugalde
- Chemical Signalling, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Friedrich-Ebert-Allee 144, D-53113Bonn, Germany
| | - Elias Feitosa-Araujo
- Plant Energy Biology, Institute of Plant Biology and Biotechnology (IBBP), University of Münster, Schlossplatz 8, D-48143Münster, Germany
| | - Karl-Josef Dietz
- Biochemistry and Physiology of Plants, Faculty of Biology, W5-134, Bielefeld University, University Street 25, D-33501Bielefeld, Germany
| | - Markus Schwarzländer
- Plant Energy Biology, Institute of Plant Biology and Biotechnology (IBBP), University of Münster, Schlossplatz 8, D-48143Münster, Germany
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23
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Khan A, Jalil S, Cao H, Tsago Y, Sunusi M, Chen Z, Shi C, Jin X. The Purple Leaf ( pl6) Mutation Regulates Leaf Color by Altering the Anthocyanin and Chlorophyll Contents in Rice. PLANTS 2020; 9:plants9111477. [PMID: 33153036 PMCID: PMC7693866 DOI: 10.3390/plants9111477] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/29/2020] [Accepted: 10/30/2020] [Indexed: 11/16/2022]
Abstract
The anthocyanin biosynthesis attracts strong interest due to the potential antioxidant value and as an important morphological marker. However, the underlying mechanism of anthocyanin accumulation in plant tissues is not clearly understood. Here, a rice mutant with a purple color in the leaf blade, named pl6, was developed from wild type (WT), Zhenong 41, with gamma ray treatment. By map-based cloning, the OsPL6 gene was located on the short arm of chromosome 6. The multiple mutations, such as single nucleotide polymorphism (SNP) at −702, −598, −450, an insertion at −119 in the promoter, three SNPs and one 6-bp deletion in the 5′-UTR region, were identified, which could upregulate the expression of OsPL6 to accumulate anthocyanin. Subsequently, the transcript level of structural genes in the anthocyanin biosynthesis pathway, including OsCHS, OsPAL, OsF3H and OsF3′H, was elevated significantly. Histological analysis revealed that the light attenuation feature of anthocyanin has degraded the grana and stroma thylakoids, which resulted in poor photosynthetic efficiency of purple leaves. Despite this, the photoabatement and antioxidative activity of anthocyanin have better equipped the pl6 mutant to minimize the oxidative damage. Moreover, the contents of abscisic acid (ABA) and cytokanin (CK) were elevated along with anthocyanin accumulation in the pl6 mutant. In conclusion, our results demonstrate that activation of OsPL6 could be responsible for the purple coloration in leaves by accumulating excessive anthocyanin and further reveal that anthocyanin acts as a strong antioxidant to scavenge reactive oxygen species (ROS) and thus play an important role in tissue maintenance.
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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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25
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Kłodawska K, Kovács L, Vladkova R, Rzaska A, Gombos Z, Laczkó-Dobos H, Malec P. Trimeric organization of photosystem I is required to maintain the balanced photosynthetic electron flow in cyanobacterium Synechocystis sp. PCC 6803. PHOTOSYNTHESIS RESEARCH 2020; 143:251-262. [PMID: 31848802 DOI: 10.1007/s11120-019-00696-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 12/02/2019] [Indexed: 06/10/2023]
Abstract
In Synechocystis sp. PCC 6803 and some other cyanobacteria photosystem I reaction centres exist predominantly as trimers, with minor contribution of monomeric form, when cultivated at standard optimized conditions. In contrast, in plant chloroplasts photosystem I complex is exclusively monomeric. The functional significance of trimeric organization of cyanobacterial photosystem I remains not fully understood. In this study, we compared the photosynthetic characteristics of PSI in wild type and psaL knockout mutant. The results show that relative to photosystem I trimer in wild-type cells, photosystem I monomer in psaL- mutant has a smaller P700+ pool size under low and moderate light, slower P700 oxidation upon dark-to-light transition, and slower P700+ reduction upon light-to-dark transition. The mutant also shows strongly diminished photosystem I donor side limitations [quantum yield Y(ND)] at low, moderate and high light, but enhanced photosystem I acceptor side limitations [quantum yield Y(NA)], especially at low light (22 µmol photons m-2 s-1). In line with these functional characteristics are the determined differences in the relative expression genes encoding of selected electron transporters. The psaL- mutant showed significant (ca fivefold) upregulation of the photosystem I donor cytochrome c6, and downregulation of photosystem I acceptors (ferredoxin, flavodoxin) and proteins of alternative electron flows originating in photosystem I acceptor side. Taken together, our results suggest that photosystem I trimerization in wild-type Synechocystis cells plays a role in the protection of photosystem I from photoinhibition via maintaining enhanced donor side electron transport limitations and minimal acceptor side electron transport limitations at various light intensities.
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Affiliation(s)
- Kinga Kłodawska
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387, Kraków, Poland.
| | - László Kovács
- Biological Research Centre, Hungarian Academy of Sciences, Szeged, 6726, Hungary
| | - Radka Vladkova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria
| | - Agnieszka Rzaska
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387, Kraków, Poland
| | - Zoltán Gombos
- Biological Research Centre, Hungarian Academy of Sciences, Szeged, 6726, Hungary
| | | | - Przemysław Malec
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387, Kraków, Poland
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26
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Yang Q, Blanco NE, Hermida-Carrera C, Lehotai N, Hurry V, Strand Å. Two dominant boreal conifers use contrasting mechanisms to reactivate photosynthesis in the spring. Nat Commun 2020; 11:128. [PMID: 31913273 PMCID: PMC6949249 DOI: 10.1038/s41467-019-13954-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 12/05/2019] [Indexed: 01/25/2023] Open
Abstract
Boreal forests are dominated by evergreen conifers that show strongly regulated seasonal photosynthetic activity. Understanding the mechanisms behind seasonal modulation of photosynthesis is crucial for predicting how these forests will respond to changes in seasonal patterns and how this will affect their role in the terrestrial carbon cycle. We demonstrate that the two co-occurring dominant boreal conifers, Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies), use contrasting mechanisms to reactivate photosynthesis in the spring. Scots pine downregulates its capacity for CO2 assimilation during winter and activates alternative electron sinks through accumulation of PGR5 and PGRL1 during early spring until the capacity for CO2 assimilation is recovered. In contrast, Norway spruce lacks this ability to actively switch between different electron sinks over the year and as a consequence suffers severe photooxidative damage during the critical spring period.
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Affiliation(s)
- Qi Yang
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE 901 87, Umeå, Sweden
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, 100091, China
| | - Nicolás E Blanco
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE 901 87, Umeå, Sweden.
- Centre of Photosynthetic and Biochemical Studies (CEFOBI-CONICET), Faculty of Biochemical Science and Pharmacy, Rosario National University, S2002LRK, Rosario, Argentina.
| | - Carmen Hermida-Carrera
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE 901 87, Umeå, Sweden
| | - Nóra Lehotai
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE 901 87, Umeå, Sweden
| | - Vaughan Hurry
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE 901 83, Umeå, Sweden.
| | - Åsa Strand
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE 901 87, Umeå, Sweden.
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27
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Essemine J, Lyu MJA, Qu M, Perveen S, Khan N, Song Q, Chen G, Zhu XG. Contrasting Responses of Plastid Terminal Oxidase Activity Under Salt Stress in Two C 4 Species With Different Salt Tolerance. FRONTIERS IN PLANT SCIENCE 2020; 11:1009. [PMID: 32733515 PMCID: PMC7359412 DOI: 10.3389/fpls.2020.01009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 06/19/2020] [Indexed: 05/07/2023]
Abstract
The present study reveals contrasting responses of photosynthesis to salt stress in two C4 species: a glycophyte Setaria viridis (SV) and a halophyte Spartina alterniflora (SA). Specifically, the effect of short-term salt stress treatment on the photosynthetic CO2 uptake and electron transport were investigated in SV and its salt-tolerant close relative SA. In this experiment, at the beginning, plants were grown in soil then were exposed to salt stress under hydroponic conditions for two weeks. SV demonstrated a much higher susceptibility to salt stress than SA; while, SV was incapable to survive subjected to about 100 mM, SA can tolerate salt concentrations up to 550 mM with slight effect on photosynthetic CO2 uptake rates and electrons transport chain conductance (gETC ). Regardless the oxygen concentration used, our results show an enhancement in the P700 oxidation with increasing O2 concentration for SV following NaCl treatment and almost no change for SA. We also observed an activation of the cyclic NDH-dependent pathway in SV by about 2.36 times upon exposure to 50 mM NaCl for 12 days (d); however, its activity in SA drops by about 25% compared to the control without salt treatment. Using PTOX inhibitor (n-PG) and that of the Qo-binding site of Cytb6/f (DBMIB), at two O2 levels (2 and 21%), to restrict electrons flow towards PSI, we successfully revealed the presence of a possible PTOX activity under salt stress for SA but not for SV. However, by q-PCR and western-blot analysis, we showed an increase in PTOX amount by about 3-4 times for SA under salt stress but not or very less for SV. Overall, this study provides strong proof for the existence of PTOX as an alternative electron pathway in C4 species (SA), which might play more than a photoprotective role under salt stress.
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28
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Sagun JV, Badger MR, Chow WS, Ghannoum O. Cyclic electron flow and light partitioning between the two photosystems in leaves of plants with different functional types. PHOTOSYNTHESIS RESEARCH 2019; 142:321-334. [PMID: 31520186 PMCID: PMC6874625 DOI: 10.1007/s11120-019-00666-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 08/26/2019] [Indexed: 05/05/2023]
Abstract
Cyclic electron flow (CEF) around photosystem I (PSI) is essential for generating additional ATP and enhancing efficient photosynthesis. Accurate estimation of CEF requires knowledge of the fractions of absorbed light by PSI (fI) and PSII (fII), which are only known for a few model species such as spinach. No measures of fI are available for C4 grasses under different irradiances. We developed a new method to estimate (1) fII in vivo by concurrently measuring linear electron flux through both photosystems [Formula: see text] in leaf using membrane inlet mass spectrometry (MIMS) and total electron flux through PSII (ETR2) using chlorophyll fluorescence by a Dual-PAM at low light and (2) CEF as ETR1-[Formula: see text]. For a C3 grass, fI was 0.5 and 0.4 under control (high light) and shade conditions, respectively. C4 species belonging to NADP-ME and NAD-ME subtypes had fI of 0.6 and PCK subtype had 0.5 under control. All shade-grown C4 species had fI of 0.6 except for NADP-ME grass which had 0.7. It was also observed that fI ranged between 0.3 and 0.5 for gymnosperm, liverwort and fern species. CEF increased with irradiance and was induced at lower irradiances in C4 grasses and fern relative to other species. CEF was greater in shade-grown plants relative to control plants except for C4 NADP-ME species. Our study reveals a range of CEF and fI values in different plant functional groups. This variation must be taken into account for improved photosynthetic calculations and modelling.
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Affiliation(s)
- Julius Ver Sagun
- ARC Centre of Excellence for Translational Photosynthesis, Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, Locked Bag 1797, Penrith, NSW 2751 Australia
| | - Murray R. Badger
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, ACT 2601 Australia
| | - Wah Soon Chow
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, ACT 2601 Australia
| | - Oula Ghannoum
- ARC Centre of Excellence for Translational Photosynthesis, Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, Locked Bag 1797, Penrith, NSW 2751 Australia
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29
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Role and regulation of class-C flavodiiron proteins in photosynthetic organisms. Biochem J 2019; 476:2487-2498. [DOI: 10.1042/bcj20180648] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 08/21/2019] [Accepted: 08/22/2019] [Indexed: 12/29/2022]
Abstract
Abstract
The regulation of photosynthesis is crucial to efficiently support the assimilation of carbon dioxide and to prevent photodamage. One key regulatory mechanism is the pseudo-cyclic electron flow (PCEF) mediated by class-C flavodiiron proteins (FLVs). These enzymes use electrons coming from Photosystem I (PSI) to reduce oxygen to water, preventing over-reduction in the acceptor side of PSI. FLVs are widely distributed among organisms performing oxygenic photosynthesis and they have been shown to be fundamental in many different conditions such as fluctuating light, sulfur deprivation and plant submersion. Moreover, since FLVs reduce oxygen they can help controlling the redox status of the cell and maintaining the microoxic environment essential for processes such as nitrogen fixation in cyanobacteria. Despite these important roles identified in various species, the genes encoding for FLV proteins have been lost in angiosperms where their activity could have been at least partially compensated by a more efficient cyclic electron flow (CEF). The present work reviews the information emerged on FLV function, analyzing recent structural data that suggest FLV could be regulated through a conformational change.
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30
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Huang W, Yang YJ, Zhang SB. The role of water-water cycle in regulating the redox state of photosystem I under fluctuating light. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:383-390. [PMID: 30890407 DOI: 10.1016/j.bbabio.2019.03.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 12/18/2018] [Accepted: 03/14/2019] [Indexed: 10/27/2022]
Abstract
The regulation of photosystem I (PSI) redox state under fluctuating light was investigated for four species using P700 measurement and electrochromic shift analysis. Species included the angiosperms Camellia japonica, Bletilla striata and Arabidopsis thaliana and the fern Cyrtomium fortunei. For the first seconds after transition from low to high light, all species showed relatively low levels of the proton gradient (ΔpH) across the thylakoid membranes. At this moment, PSI was highly oxidized in C. japonica and C. fortunei but was over-reduced in B. striata and A. thaliana. In B. striata and A. thaliana, the redox state of PSI was largely dependent on ΔpH. In contrast, the rapid oxidation of P700 in C. japonica was relatively independent of ΔpH, but was mainly dependent on the outflow of electrons to O2 via the water-water cycle. In the fern C. fortunei, PSI redox state was rapidly regulated by the fast photo-reduction of O2 rather than the ΔpH. These results indicate that mechanisms regulating PSI redox state under fluctuating light differ greatly between species. We propose that the water-water cycle is an important mechanism regulating the PSI redox state in angiosperms.
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Affiliation(s)
- Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - 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.
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31
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Zlobin IE, Ivanov YV, Kartashov AV, Sarvin BA, Stavrianidi AN, Kreslavski VD, Kuznetsov VV. Impact of weak water deficit on growth, photosynthetic primary processes and storage processes in pine and spruce seedlings. PHOTOSYNTHESIS RESEARCH 2019; 139:307-323. [PMID: 29779192 DOI: 10.1007/s11120-018-0520-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/15/2018] [Indexed: 06/08/2023]
Abstract
We investigated the influence of 40 days of drought on growth, storage processes and primary photosynthetic processes in 3-month-old Scots pine and Norway spruce seedlings growing in perlite culture. Water stress significantly affected seedling water status, whereas absolute dry biomass growth was not substantially influenced. Water stress induced an increase in non-structural carbohydrate content (sugars, sugar alcohols, starch) in the aboveground part of pine seedlings in contrast to spruce seedlings. Due to the relatively low content of sugars and sugar alcohols in seedling organs, their expected contribution to osmotic potential changes was quite low. In contrast to biomass accumulation and storage, photosynthetic primary processes were substantially influenced by water shortage. In spruce seedlings, PSII was more sensitive to water stress than PSI. In particular, electron transport in PSI was stable under water stress despite the substantial decrease of electron transport in PSII. The increase in thermal energy dissipation due to enhancement of non-photochemical quenching (NPQ) was evident in both species under water stress. Simultaneously, the yields of non-regulated energy dissipation in PSII were decreased in pine seedlings under drought. A relationship between growth, photosynthetic activities and storage processes is analysed under weak water deficit.
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Affiliation(s)
- Ilya E Zlobin
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russia
| | - Yury V Ivanov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russia.
| | - Alexander V Kartashov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russia
| | | | | | - Vladimir D Kreslavski
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russia
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Russia
| | - Vladimir V Kuznetsov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russia
- Tomsk State University, Tomsk, Russia
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32
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Shimakawa G, Miyake C. Oxidation of P700 Ensures Robust Photosynthesis. FRONTIERS IN PLANT SCIENCE 2018; 9:1617. [PMID: 30459798 PMCID: PMC6232666 DOI: 10.3389/fpls.2018.01617] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/18/2018] [Indexed: 05/18/2023]
Abstract
In the light, photosynthetic cells can potentially suffer from oxidative damage derived from reactive oxygen species. Nevertheless, a variety of oxygenic photoautotrophs, including cyanobacteria, algae, and plants, manage their photosynthetic systems successfully. In the present article, we review previous research on how these photoautotrophs safely utilize light energy for photosynthesis without photo-oxidative damage to photosystem I (PSI). The reaction center chlorophyll of PSI, P700, is kept in an oxidized state in response to excess light, under high light and low CO2 conditions, to tune the light utilization and dissipate the excess photo-excitation energy in PSI. Oxidation of P700 is co-operatively regulated by a number of molecular mechanisms on both the electron donor and acceptor sides of PSI. The strategies to keep P700 oxidized are diverse among a variety of photoautotrophs, which are evolutionarily optimized for their ecological niche.
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Affiliation(s)
- Ginga Shimakawa
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Chikahiro Miyake
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, Kobe, Japan
- Core Research for Environmental Science and Technology, Japan Science and Technology Agency, Tokyo, Japan
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33
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Measurement of O 2 Uptake and Evolution in Leaves In Vivo Using Stable Isotopes and Membrane Inlet Mass Spectrometry. Methods Mol Biol 2018. [PMID: 29978401 DOI: 10.1007/978-1-4939-7786-4_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Oxygen is both product and substrate of photosynthesis and metabolism in plants, by oxygen evolution through water splitting and uptake by photorespiration and respiration. It is important to investigate these processes simultaneously in leaves, especially in response to environmental variables, such as light and temperature. To distinguish between processes that evolve or take up O2 in leaves in the light, in vivo gas exchange of stable isotopes of oxygen and membrane inlet mass spectrometry is used. A closed-cuvette system for gas exchange of leaf disks is described, using the stable isotopes 16O2 and 18O2, with a semipermeable membrane gas inlet and isotope mass separation and detection by mass spectrometry. Measurement of evolution and uptake, as well as CO2 uptake, at a range of light levels allows composition of a light-response curve, here described for French bean and maize leaf disks.
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34
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Rea G, Antonacci A, Lambreva MD, Mattoo AK. Features of cues and processes during chloroplast-mediated retrograde signaling in the alga Chlamydomonas. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 272:193-206. [PMID: 29807591 DOI: 10.1016/j.plantsci.2018.04.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/04/2018] [Accepted: 04/23/2018] [Indexed: 06/08/2023]
Abstract
Retrograde signaling is an intracellular communication process defined by cues generated in chloroplast and mitochondria which traverse membranes to their destination in the nucleus in order to regulate nuclear gene expression and protein synthesis. The coding and decoding of such organellar message(s) involve gene medleys and metabolic components about which more is known in higher plants than the unicellular organisms such as algae. Chlamydomonas reinhardtii is an oxygenic microalgal model for genetic and physiological studies. It harbors a single chloroplast and is amenable for generating mutants. The focus of this review is on studies that delineate retrograde signaling in Chlamydomonas vis a vis higher plants. Thus, communication networks between chloroplast and nucleus involving photosynthesis- and ROS-generated signals, functional tetrapyrrole biosynthesis intermediates, and Ca2+-signaling that modulate nuclear gene expression in this alga are discussed. Conceptually, different signaling components converge to regulate either the same or functionally-overlapping gene products.
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Affiliation(s)
- Giuseppina Rea
- Institute of Crystallography, National Research Council of Italy, Via Salaria Km 29, 3 00015 Monterotondo Scalo, Rome, Italy
| | - Amina Antonacci
- Institute of Crystallography, National Research Council of Italy, Via Salaria Km 29, 3 00015 Monterotondo Scalo, Rome, Italy
| | - Maya D Lambreva
- Institute of Crystallography, National Research Council of Italy, Via Salaria Km 29, 3 00015 Monterotondo Scalo, Rome, Italy
| | - Autar K Mattoo
- The Henry A Wallace Agricultural Research Centre, U.S. Department of Agriculture, Sustainable Agricultural Systems Laboratory, Beltsville, MD 20705, USA.
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35
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Mullineaux PM, Exposito-Rodriguez M, Laissue PP, Smirnoff N. ROS-dependent signalling pathways in plants and algae exposed to high light: Comparisons with other eukaryotes. Free Radic Biol Med 2018; 122:52-64. [PMID: 29410363 DOI: 10.1016/j.freeradbiomed.2018.01.033] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 01/27/2018] [Accepted: 01/31/2018] [Indexed: 01/09/2023]
Abstract
Like all aerobic organisms, plants and algae co-opt reactive oxygen species (ROS) as signalling molecules to drive cellular responses to changes in their environment. In this respect, there is considerable commonality between all eukaryotes imposed by the constraints of ROS chemistry, similar metabolism in many subcellular compartments, the requirement for a high degree of signal specificity and the deployment of thiol peroxidases as transducers of oxidising equivalents to regulatory proteins. Nevertheless, plants and algae carry out specialised signalling arising from oxygenic photosynthesis in chloroplasts and photoautotropism, which often induce an imbalance between absorption of light energy and the capacity to use it productively. A key means of responding to this imbalance is through communication of chloroplasts with the nucleus to adjust cellular metabolism. Two ROS, singlet oxygen (1O2) and hydrogen peroxide (H2O2), initiate distinct signalling pathways when photosynthesis is perturbed. 1O2, because of its potent reactivity means that it initiates but does not transduce signalling. In contrast, the lower reactivity of H2O2 means that it can also be a mobile messenger in a spatially-defined signalling pathway. How plants translate a H2O2 message to bring about changes in gene expression is unknown and therefore, we draw on information from other eukaryotes to propose a working hypothesis. The role of these ROS generated in other subcellular compartments of plant cells in response to HL is critically considered alongside other eukaryotes. Finally, the responses of animal cells to oxidative stress upon high irradiance exposure is considered for new comparisons between plant and animal cells.
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Affiliation(s)
- Philip M Mullineaux
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK.
| | | | | | - Nicholas Smirnoff
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
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36
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Gómez R, Carrillo N, Morelli MP, Tula S, Shahinnia F, Hajirezaei MR, Lodeyro AF. Faster photosynthetic induction in tobacco by expressing cyanobacterial flavodiiron proteins in chloroplasts. PHOTOSYNTHESIS RESEARCH 2018; 136:129-138. [PMID: 29022124 DOI: 10.1007/s11120-017-0449-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 09/26/2017] [Indexed: 05/02/2023]
Abstract
Plants grown in the field experience sharp changes in irradiation due to shading effects caused by clouds, other leaves, etc. The excess of absorbed light energy is dissipated by a number of mechanisms including cyclic electron transport, photorespiration, and Mehler-type reactions. This protection is essential for survival but decreases photosynthetic efficiency. All phototrophs except angiosperms harbor flavodiiron proteins (Flvs) which relieve the excess of excitation energy on the photosynthetic electron transport chain by reducing oxygen directly to water. Introduction of cyanobacterial Flv1/Flv3 in tobacco chloroplasts resulted in transgenic plants that showed similar photosynthetic performance under steady-state illumination, but displayed faster recovery of various photosynthetic parameters, including electron transport and non-photochemical quenching during dark-light transitions. They also kept the electron transport chain in a more oxidized state and enhanced the proton motive force of dark-adapted leaves. The results indicate that, by acting as electron sinks during light transitions, Flvs contribute to increase photosynthesis protection and efficiency under changing environmental conditions as those found by plants in the field.
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Affiliation(s)
- Rodrigo Gómez
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000, Rosario, Argentina
| | - Néstor Carrillo
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000, Rosario, Argentina
| | - María P Morelli
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000, Rosario, Argentina
- Departamento de Química Biológica (QB 23), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (UBA), C1428EGA, Buenos Aires, Argentina
| | - Suresh Tula
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse, 06466, Stadt Seeland, Germany
| | - Fahimeh Shahinnia
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse, 06466, Stadt Seeland, Germany
| | - Mohammad-Reza Hajirezaei
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse, 06466, Stadt Seeland, Germany
| | - Anabella F Lodeyro
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000, Rosario, Argentina.
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Dann M, Leister D. Enhancing (crop) plant photosynthesis by introducing novel genetic diversity. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0380. [PMID: 28808099 DOI: 10.1098/rstb.2016.0380] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2017] [Indexed: 12/22/2022] Open
Abstract
Although some elements of the photosynthetic light reactions might appear to be ideal, the overall efficiency of light conversion to biomass has not been optimized during evolution. Because crop plants are depleted of genetic diversity for photosynthesis, efforts to enhance its efficiency with respect to light conversion to yield must generate new variation. In principle, three sources of natural variation are available: (i) rare diversity within extant higher plant species, (ii) photosynthetic variants from algae, and (iii) reconstruction of no longer extant types of plant photosynthesis. Here, we argue for a novel approach that outsources crop photosynthesis to a cyanobacterium that is amenable to adaptive evolution. This system offers numerous advantages, including a short generation time, virtually unlimited population sizes and high mutation rates, together with a versatile toolbox for genetic manipulation. On such a synthetic bacterial platform, 10 000 years of (crop) plant evolution can be recapitulated within weeks. Limitations of this system arise from its unicellular nature, which cannot reproduce all aspects of crop photosynthesis. But successful establishment of such a bacterial host for crop photosynthesis promises not only to enhance the performance of eukaryotic photosynthesis but will also reveal novel facets of the molecular basis of photosynthetic flexibility.This article is part of the themed issue 'Enhancing photosynthesis in crop plants: targets for improvement'.
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Affiliation(s)
- Marcel Dann
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians University of Munich, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany
| | - Dario Leister
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians University of Munich, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany
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Noridomi M, Nakamura S, Tsuyama M, Futamura N, Vladkova R. Opposite domination of cyclic and pseudocyclic electron flows in short-illuminated dark-adapted leaves of angiosperms and gymnosperms. PHOTOSYNTHESIS RESEARCH 2017; 134:149-164. [PMID: 28689227 DOI: 10.1007/s11120-017-0419-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 07/03/2017] [Indexed: 06/07/2023]
Abstract
The present work was aimed to explain the recently reported higher O2-dependent electron flow capacity in gymnosperms than in angiosperms and to search for other differences in the electron transport processes by simultaneous characterization of the relative capacities of pseudocyclic (direct or Flavodiiron proteins (Flv)-mediated O2-reduction, Mehler(-like) reactions) and cyclic electron flows around photosystem I (CEF-PSI). To this end, a comparative multicomponent analysis was performed on the fluorescence decay curves of dark-adapted leaves after illumination with a 1-s saturating light pulse. In both gymnosperms and angiosperms, two or three exponential decay components were resolved: fast (t 1/21 ~ 170-260 ms), middle (~1.0-2.3 s), and slow (>4.2 s). The sensitivity of the decay parameters (amplitudes A1-3, halftimes t 1/2 1-3) to the alternative electron flows was assessed using Arabidopsis pgr5 and ndhM mutants, defective in CEF-PSI, Synechocystis sp. PCC 6803 Δflv1 mutant, defective in Flv-mediated O2-photoreduction, different O2 concentrations, and methyl viologen treatment. A1 reflected the part of electrons involved in linear and O2-photoreduction pathways after PSI. The middle component appeared in pgr5 (but not in ndhM), in gymnosperms under low O2, and in Δflv1, and reflected limitations at the PSI acceptor side. The slow component was sensitive to CEF-PSI. The comparison of decay parameters provided evidence that Flv mediate O2-photoreduction in gymnosperms, which explains their higher O2-dependent electron flow capacity. The concomitant quantification of relative electrons branching in O2-photoreduction and CEF-PSI pathways under the applied non-steady-state photosynthetic conditions reveals that CEF-PSI capacity significantly exceeds that of O2-photoreduction in angiosperms while the opposite occurs in gymnosperms.
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Affiliation(s)
- Mari Noridomi
- Department of Agriculture, Forest and Forest Products Sciences, Plant Metabolic Physiology, Kyushu University, Fukuoka, 812-8581, Japan
| | - Shouta Nakamura
- Department of Agriculture, Forest and Forest Products Sciences, Plant Metabolic Physiology, Kyushu University, Fukuoka, 812-8581, Japan
| | - Michito Tsuyama
- Department of Agriculture, Forest and Forest Products Sciences, Plant Metabolic Physiology, Kyushu University, Fukuoka, 812-8581, Japan.
| | - Norihiro Futamura
- Department of Molecular and Cell Biology, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Radka Vladkova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev St. 21, 1113, Sofia, Bulgaria
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Takagi D, Amako K, Hashiguchi M, Fukaki H, Ishizaki K, Goh T, Fukao Y, Sano R, Kurata T, Demura T, Sawa S, Miyake C. Chloroplastic ATP synthase builds up a proton motive force preventing production of reactive oxygen species in photosystem I. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 91:306-324. [PMID: 28380278 DOI: 10.1111/tpj.13566] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 03/29/2017] [Accepted: 04/03/2017] [Indexed: 05/19/2023]
Abstract
Over-reduction of the photosynthetic electron transport (PET) chain should be avoided, because the accumulation of reducing electron carriers produces reactive oxygen species (ROS) within photosystem I (PSI) in thylakoid membranes and causes oxidative damage to chloroplasts. To prevent production of ROS in thylakoid membranes the H+ gradient (ΔpH) needs to be built up across the thylakoid membranes to suppress the over-reduction state of the PET chain. In this study, we aimed to identify the critical component that stimulates ΔpH formation under illumination in higher plants. To do this, we screened ethyl methane sulfonate (EMS)-treated Arabidopsis thaliana, in which the formation of ΔpH is impaired and the PET chain caused over-reduction under illumination. Subsequently, we isolated an allelic mutant that carries a missense mutation in the γ-subunit of chloroplastic CF0 CF1 -ATP synthase, named hope2. We found that hope2 suppressed the formation of ΔpH during photosynthesis because of the high H+ efflux activity from the lumenal to stromal side of the thylakoid membranes via CF0 CF1 -ATP synthase. Furthermore, PSI was in a more reduced state in hope2 than in wild-type (WT) plants, and hope2 was more vulnerable to PSI photoinhibition than WT under illumination. These results suggested that chloroplastic CF0 CF1 -ATP synthase adjusts the redox state of the PET chain, especially for PSI, by modulating H+ efflux activity across the thylakoid membranes. Our findings suggest the importance of the buildup of ΔpH depending on CF0 CF1 -ATP synthase to adjust the redox state of the reaction center chlorophyll P700 in PSI and to suppress the production of ROS in PSI during photosynthesis.
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Affiliation(s)
- Daisuke Takagi
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
- Core Research for Environmental Science and Technology, Japan Science and Technology Agency, 7 Gobancho, Chiyoda-ku, Tokyo, 102-0076, Japan
| | - Katsumi Amako
- Faculty of Nutrition, Kobe Gakuin University, Kobe, 651-2180, Japan
| | - Masaki Hashiguchi
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
| | - Hidehiro Fukaki
- Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501, Japan
| | - Kimitsune Ishizaki
- Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501, Japan
| | - Tatsuaki Goh
- Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501, Japan
| | - Yoichiro Fukao
- Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, 630-0192, Japan
| | - Ryosuke Sano
- Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, 630-0192, Japan
| | - Tetsuya Kurata
- Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, 630-0192, Japan
- Graduate School of Life Sciences, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, 980-8578, Japan
| | - Taku Demura
- Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Ikoma, 630-0192, Japan
| | - Shinichiro Sawa
- Graduate School of Science and Technology, Kumamoto University, Kurokami, Tyuou-ku, Kumamoto, 860-8555, Japan
| | - Chikahiro Miyake
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
- Core Research for Environmental Science and Technology, Japan Science and Technology Agency, 7 Gobancho, Chiyoda-ku, Tokyo, 102-0076, Japan
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Moustakas M, Malea P, Haritonidou K, Sperdouli I. Copper bioaccumulation, photosystem II functioning, and oxidative stress in the seagrass Cymodocea nodosa exposed to copper oxide nanoparticles. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:16007-16018. [PMID: 28537017 DOI: 10.1007/s11356-017-9174-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 05/01/2017] [Indexed: 05/12/2023]
Abstract
Photosynthetic activity, oxidative stress, and Cu bioaccumulation in the seagrass Cymodocea nodosa were assessed 4, 12, 24, 48, and 72 h after exposure to two copper oxide nanoparticle (CuO NP) concentrations (5 and 10 mg L-1). CuO NPs were characterized by scanning electron microscopy (SEM) and dynamic light scattering measurements (DLS). Chlorophyll fluorescence analysis was applied to detect photosystem II (PSII) functionality, while the Cu accumulation kinetics into the leaf blades was fitted to the Michaelis-Menten equation. The uptake kinetics was rapid during the first 4 h of exposure and reached an equilibrium state after 10 h exposure to 10 mg L-1 and after 27 h to 5 mg L-1 CuO NPs. As a result, 4-h treatment with 5 mg L-1 CuO NPs, decreased the quantum yield of PS II photochemistry (Φ PSΙΙ ) with a parallel increase in the regulated non-photochemical energy loss in PSII (Φ NPQ ). However, the photoprotective dissipation of excess absorbed light energy as heat, through the process of non-photochemical quenching (NPQ), did not maintain the same fraction of open reaction centers (q p ) as in control plants. This reduced number of open reaction centers resulted in a significant increase of H2O2 production in the leaf veins serving possibly as an antioxidant defense signal. Twenty-four-hour treatment had no significant effect on Φ PSΙΙ and q p compared to controls. However, 24 h exposure to 5 mg L-1 CuO NPs increased the quantum yield of non-regulated energy loss in PSII (Φ NO ), and thus the formation of singlet oxygen (1O2) via the triplet state of chlorophyll, possible because the uptake kinetics had not yet reached the equilibrium state as did 10 mg L-1. Longer-duration treatment (48 and 72 h) had less effect on the allocation of absorbed light energy at PSII and the fraction of open reaction centers, compared to 4-h treatment, suggesting the function of a stress defense mechanism. The response of C. nodosa leaves to CuO NPs fits the "Threshold for Tolerance Model" with a threshold time (more than 4 h) required for induction of a stress defense mechanism, through H2O2 production.
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Affiliation(s)
- Michael Moustakas
- Department of Botany, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece.
- Division of Botany, Department of Biology, Faculty of Science, Istanbul University, 34134, Istanbul, Turkey.
| | - Paraskevi Malea
- Department of Botany, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | - Katerina Haritonidou
- Department of Botany, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | - Ilektra Sperdouli
- Department of Botany, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
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Exposito-Rodriguez M, Laissue PP, Yvon-Durocher G, Smirnoff N, Mullineaux PM. Photosynthesis-dependent H 2O 2 transfer from chloroplasts to nuclei provides a high-light signalling mechanism. Nat Commun 2017; 8:49. [PMID: 28663550 PMCID: PMC5491514 DOI: 10.1038/s41467-017-00074-w] [Citation(s) in RCA: 213] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 05/26/2017] [Indexed: 12/30/2022] Open
Abstract
Chloroplasts communicate information by signalling to nuclei during acclimation to fluctuating light. Several potential operating signals originating from chloroplasts have been proposed, but none have been shown to move to nuclei to modulate gene expression. One proposed signal is hydrogen peroxide (H2O2) produced by chloroplasts in a light-dependent manner. Using HyPer2, a genetically encoded fluorescent H2O2 sensor, we show that in photosynthetic Nicotiana benthamiana epidermal cells, exposure to high light increases H2O2 production in chloroplast stroma, cytosol and nuclei. Critically, over-expression of stromal ascorbate peroxidase (H2O2 scavenger) or treatment with DCMU (photosynthesis inhibitor) attenuates nuclear H2O2 accumulation and high light-responsive gene expression. Cytosolic ascorbate peroxidase over-expression has little effect on nuclear H2O2 accumulation and high light-responsive gene expression. This is because the H2O2 derives from a sub-population of chloroplasts closely associated with nuclei. Therefore, direct H2O2 transfer from chloroplasts to nuclei, avoiding the cytosol, enables photosynthetic control over gene expression.Multiple plastid-derived signals have been proposed but not shown to move to the nucleus to promote plant acclimation to fluctuating light. Here the authors use a fluorescent hydrogen peroxide sensor to provide evidence that H2O2 is transferred directly from chloroplasts to nuclei to control nuclear gene expression.
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Affiliation(s)
- Marino Exposito-Rodriguez
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
| | | | - Gabriel Yvon-Durocher
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9EZ, UK
| | - Nicholas Smirnoff
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK.
| | - Philip M Mullineaux
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK.
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Ilík P, Pavlovič A, Kouřil R, Alboresi A, Morosinotto T, Allahverdiyeva Y, Aro EM, Yamamoto H, Shikanai T. Alternative electron transport mediated by flavodiiron proteins is operational in organisms from cyanobacteria up to gymnosperms. THE NEW PHYTOLOGIST 2017; 214:967-972. [PMID: 28304077 DOI: 10.1111/nph.14536] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 02/28/2017] [Indexed: 05/09/2023]
Abstract
Photo-reduction of O2 to water mediated by flavodiiron proteins (FDPs) represents a safety valve for the photosynthetic electron transport chain in fluctuating light. So far, the FDP-mediated O2 photo-reduction has been evidenced only in cyanobacteria and the moss Physcomitrella; however, a recent phylogenetic analysis of transcriptomes of photosynthetic organisms has also revealed the presence of FDP genes in several nonflowering plant groups. What remains to be clarified is whether the FDP-dependent O2 photo-reduction is actually operational in these organisms. We have established a simple method for the monitoring of FDP-mediated O2 photo-reduction, based on the measurement of redox kinetics of P700 (the electron donor of photosystem I) upon dark-to-light transition. The O2 photo-reduction is manifested as a fast re-oxidation of P700. The validity of the method was verified by experiments with transgenic organisms, namely FDP knock-out mutants of Synechocystis and Physcomitrella and transgenic Arabidopsis plants expressing FDPs from Physcomitrella. We observed the fast P700 re-oxidation in representatives of all green plant groups excluding angiosperms. Our results provide strong evidence that the FDP-mediated O2 photo-reduction is functional in all nonflowering green plant groups. This finding suggests a major change in the strategy of photosynthetic regulation during the evolution of angiosperms.
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Affiliation(s)
- Petr Ilík
- Department of Biophysics, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, 783 71, Olomouc, Czech Republic
| | - Andrej Pavlovič
- Department of Biophysics, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, 783 71, Olomouc, Czech Republic
| | - Roman Kouřil
- Department of Biophysics, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, 783 71, Olomouc, Czech Republic
| | | | | | - Yagut Allahverdiyeva
- Department of Biochemistry, Molecular Plant Biology, University of Turku, 20014, Turku, Finland
| | - Eva-Mari Aro
- Department of Biochemistry, Molecular Plant Biology, University of Turku, 20014, Turku, Finland
| | - Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, 606-8502, Kyoto, Japan
- CREST, Japan Science and Technology Agency, Chiyoda-ku, 102-0076, Tokyo, Japan
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, 606-8502, Kyoto, Japan
- CREST, Japan Science and Technology Agency, Chiyoda-ku, 102-0076, Tokyo, Japan
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Shikanai T, Yamamoto H. Contribution of Cyclic and Pseudo-cyclic Electron Transport to the Formation of Proton Motive Force in Chloroplasts. MOLECULAR PLANT 2017; 10:20-29. [PMID: 27575692 DOI: 10.1016/j.molp.2016.08.004] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 07/28/2016] [Accepted: 08/08/2016] [Indexed: 05/05/2023]
Abstract
Photosynthetic electron transport is coupled to proton translocation across the thylakoid membrane, resulting in the formation of a trans-thylakoid proton gradient (ΔpH) and membrane potential (Δψ). Ion transporters and channels localized to the thylakoid membrane regulate the contribution of each component to the proton motive force (pmf). Although both ΔpH and Δψ contribute to ATP synthesis as pmf, only ΔpH downregulates photosynthetic electron transport via the acidification of the thylakoid lumen by inducing thermal dissipation of excessive absorbed light energy from photosystem II antennae and slowing down of the electron transport through the cytochrome b6f complex. To optimize the tradeoff between efficient light energy utilization and protection of both photosystems against photodamage, plants have to regulate the pmf amplitude and its components, ΔpH and Δψ. Cyclic electron transport around photosystem I (PSI) is a major regulator of the pmf amplitude by generating pmf independently of the net production of NADPH by linear electron transport. Chloroplast ATP synthase relaxes pmf for ATP synthesis, and its activity should be finely tuned for maintaining the size of the pmf during steady-state photosynthesis. Pseudo-cyclic electron transport mediated by flavodiiron protein (Flv) forms a large electron sink, which is essential for PSI photoprotection in fluctuating light in cyanobacteria. Flv is conserved from cyanobacteria to gymnosperms but not in angiosperms. The Arabidopsis proton gradient regulation 5 (pgr5) mutant is defective in the main pathway of PSI cyclic electron transport. By introducing Physcomitrella patens genes encoding Flvs, the function of PSI cyclic electron transport was substituted by that of Flv-dependent pseudo-cyclic electron transport. In transgenic plants, the size of the pmf was complemented to the wild-type level but the contribution of ΔpH to the total pmf was lower than that in the wild type. In the pgr5 mutant, the size of the pmf was drastically lowered by the absence of PSI cyclic electron transport. In the mutant, ΔpH occupied the majority of pmf, suggesting the presence of a mechanism for the homeostasis of luminal pH in the light. To avoid damage to photosynthetic electron transport by periods of excess solar energy, plants employ an intricate regulatory network involving alternative electron transport pathways, ion transporters/channels, and pH-dependent mechanisms for downregulating photosynthetic electron transport.
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Affiliation(s)
- Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 Japan; CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076 Japan.
| | - Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 Japan; CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076 Japan
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Wang D, Fu A. The Plastid Terminal Oxidase is a Key Factor Balancing the Redox State of Thylakoid Membrane. Enzymes 2016; 40:143-171. [PMID: 27776780 DOI: 10.1016/bs.enz.2016.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
Mitochondria possess oxygen-consuming respiratory electron transfer chains (RETCs), and the oxygen-evolving photosynthetic electron transfer chain (PETC) resides in chloroplasts. Evolutionarily mitochondria and chloroplasts are derived from ancient α-proteobacteria and cyanobacteria, respectively. However, cyanobacteria harbor both RETC and PETC on their thylakoid membranes. It is proposed that chloroplasts could possess a RETC on the thylakoid membrane, in addition to PETC. Identification of a plastid terminal oxidase (PTOX) in the chloroplast from the Arabidopsis variegation mutant immutans (im) demonstrated the presence of a RETC in chloroplasts, and the PTOX is the committed oxidase. PTOX is distantly related to the mitochondrial alternative oxidase (AOX), which is responsible for the CN-insensitive alternative RETC. Similar to AOX, an ubiquinol (UQH2) oxidase, PTOX is a plastoquinol (PQH2) oxidase on the chloroplast thylakoid membrane. Lack of PTOX, Arabidopsis im showed a light-dependent variegation phenotype; and mutant plants will not survive the mediocre light intensity during its early development stage. PTOX is very important for carotenoid biosynthesis, since the phytoene desaturation, a key step in the carotenoid biosynthesis, is blocked in the white sectors of Arabidopsis im mutant. PTOX is found to be a stress-related protein in numerous research instances. It is generally believed that PTOX can protect plants from various environmental stresses, especially high light stress. PTOX also plays significant roles in chloroplast development and plant morphogenesis. Global physiological roles played by PTOX could be a direct or indirect consequence of its PQH2 oxidase activity to maintain the PQ pool redox state on the thylakoid membrane. The PTOX-dependent chloroplast RETC (so-called chlororespiration) does not contribute significantly when chloroplast PETC is normally developed and functions well. However, PTOX-mediated RETC could be the major force to regulate the PQ pool redox balance in the darkness, under conditions of stress, in nonphotosynthetic plastids, especially in the early development from proplastids to chloroplasts.
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Affiliation(s)
- D Wang
- The Key Laboratory of Western Resources Biology and Biological Technology, College of Life Sciences, Northwest University, Xian, China; Shaanxi Province Key Laboratory of Biotechnology, College of Life Sciences, Northwest University, Xian, China
| | - A Fu
- The Key Laboratory of Western Resources Biology and Biological Technology, College of Life Sciences, Northwest University, Xian, China; Shaanxi Province Key Laboratory of Biotechnology, College of Life Sciences, Northwest University, Xian, China.
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Fan DY, Fitzpatrick D, Oguchi R, Ma W, Kou J, Chow WS. Obstacles in the quantification of the cyclic electron flux around Photosystem I in leaves of C3 plants. PHOTOSYNTHESIS RESEARCH 2016; 129:239-51. [PMID: 26846653 DOI: 10.1007/s11120-016-0223-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/24/2016] [Indexed: 05/20/2023]
Abstract
Sixty years ago Arnon and co-workers discovered photophosphorylation driven by a cyclic electron flux (CEF) around Photosystem I. Since then understanding the physiological roles and the regulation of CEF has progressed, mainly via genetic approaches. One basic problem remains, however: quantifying CEF in the absence of a net product. Quantification of CEF under physiological conditions is a crucial prerequisite for investigating the physiological roles of CEF. Here we summarize current progress in methods of CEF quantification in leaves and, in some cases, in isolated thylakoids, of C3 plants. Evidently, all present methods have their own shortcomings. We conclude that to quantify CEF in vivo, the best way currently is to measure the electron flux through PS I (ETR1) and that through PS II and PS I in series (ETR2) for the whole leaf tissue under identical conditions. The difference between ETR1 and ETR2 is an upper estimate of CEF, mainly consisting, in C3 plants, of a major PGR5-PGRL1-dependent CEF component and a minor chloroplast NDH-dependent component, where PGR5 stands for Proton Gradient Regulation 5 protein, PGRL1 for PGR5-like photosynthesis phenotype 1, and NDH for Chloroplast NADH dehydrogenase-like complex. These two CEF components can be separated by the use of antimycin A to inhibit the former (major) component. Membrane inlet mass spectrometry utilizing stable oxygen isotopes provides a reliable estimation of ETR2, whilst ETR1 can be estimated from a method based on the photochemical yield of PS I, Y(I). However, some issues for the recommended method remain unresolved.
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Affiliation(s)
- Da-Yong Fan
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, The Chinese Academy of Sciences, Beijing, 100093, China
- Division of Plant Sciences, Research School of Biology, The Australian National University, 46 Sullivans Creek Road, Acton, ACT, 2601, Australia
| | - Duncan Fitzpatrick
- Division of Plant Sciences, Research School of Biology, The Australian National University, 46 Sullivans Creek Road, Acton, ACT, 2601, Australia
| | - Riichi Oguchi
- Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, 980-8578, Japan
- Division of Plant Sciences, Research School of Biology, The Australian National University, 46 Sullivans Creek Road, Acton, ACT, 2601, Australia
| | - Weimin Ma
- College of Life & Environment Sciences, Shanghai Normal University, Guilin Road 100, Shanghai, 200234, China
- Division of Plant Sciences, Research School of Biology, The Australian National University, 46 Sullivans Creek Road, Acton, ACT, 2601, Australia
| | - Jiancun Kou
- College of Animal Science and Technology, Northwest A&F University, Yangling, 712100, China
- Division of Plant Sciences, Research School of Biology, The Australian National University, 46 Sullivans Creek Road, Acton, ACT, 2601, Australia
| | - Wah Soon Chow
- Division of Plant Sciences, Research School of Biology, The Australian National University, 46 Sullivans Creek Road, Acton, ACT, 2601, Australia.
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46
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Buapet P, Björk M. The role of O2 as an electron acceptor alternative to CO2 in photosynthesis of the common marine angiosperm Zostera marina L. PHOTOSYNTHESIS RESEARCH 2016; 129:59-69. [PMID: 27125819 DOI: 10.1007/s11120-016-0268-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Accepted: 04/19/2016] [Indexed: 06/05/2023]
Abstract
This study investigates the role of O2 as an electron acceptor alternative to CO2 in photosynthesis of the common marine angiosperm Zostera marina L. Electron transport rates (ETRs) and non-photochemical quenching (NPQ) of Z. marina were measured under saturating irradiance in synthetic seawater containing 2.2 mM DIC and no DIC with different O2 levels (air-equilibrated levels, 3 % of air equilibrium and restored air-equilibrated levels). Lowering O2 did not affect ETR when DIC was provided, while it caused a decrease in ETR and an increase in NPQ in DIC-free media, indicating that O2 acted as an alternative electron acceptor under low DIC. The ETR and NPQ as a function of irradiance were subsequently assessed in synthetic seawater containing (1) 2.2 mM DIC, air-equilibrated O2; (2) saturating CO2, no O2; and (3) no DIC, air-equilibrated O2. These treatments were combined with glycolaldehyde pre-incubation. Glycolaldehyde caused a marked decrease in ETR in DIC-free medium, indicating significant electron flow supported by photorespiration. Combining glycolaldehyde with O2 depletion completely suppressed ETR suggesting the operation of the Mehler reaction, a possibility supported by the photosynthesis-dependent superoxide production. However, no notable effect of suppressing the Mehler reaction on NPQ was observed. It is concluded that during DIC-limiting conditions, such as those frequently occurring in the habitats of Z. marina, captured light energy exceeds what is utilised for the assimilation of available carbon, and photorespiration is a major alternative electron acceptor, while the contribution of the Mehler reaction is minor.
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Affiliation(s)
- Pimchanok Buapet
- Department of Biology, Faculty of Science, Prince of Songkla University, Hat Yai, 90112, Songkhla, Thailand.
| | - Mats Björk
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, SE-106 91, Sweden
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47
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Johnson GN, Stepien P. Plastid Terminal Oxidase as a Route to Improving Plant Stress Tolerance: Known Knowns and Known Unknowns. PLANT & CELL PHYSIOLOGY 2016; 57:1387-1396. [PMID: 26936791 DOI: 10.1093/pcp/pcw042] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 02/21/2016] [Indexed: 05/24/2023]
Abstract
A plastid-localized terminal oxidase, PTox, was first described due to its role in chloroplast development, with plants lacking PTox producing white sectors on their leaves. This phenotype is explained as being due to PTox playing a role in carotenoid biosynthesis, as a cofactor of phytoene desaturase. Co-occurrence of PTox with a chloroplast-localized NADPH dehydrogenase (NDH) has suggested the possibility of a functional respiratory pathway in plastids. Evidence has also been found that, in certain stress-tolerant plant species, PTox can act as an electron acceptor from PSII, making it a candidate for engineering stress-tolerant crops. However, attempts to induce such a pathway via overexpression of the PTox protein have failed to date. Here we review the current understanding of PTox function in higher plants and discuss possible barriers to inducing PTox activity to improve stress tolerance.
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Affiliation(s)
- Giles N Johnson
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Piotr Stepien
- Department of Plant Nutrition, Wroclaw University of Environmental and Life Sciences, ul. Grunwaldzka 53, 50-357 Wroclaw, Poland
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48
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Light-induced gradual activation of photosystem II in dark-grown Norway spruce seedlings. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:799-809. [DOI: 10.1016/j.bbabio.2016.02.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 02/12/2016] [Accepted: 02/17/2016] [Indexed: 11/19/2022]
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49
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Stefanov M, Yotsova E, Rashkov G, Ivanova K, Markovska Y, Apostolova EL. Effects of salinity on the photosynthetic apparatus of two Paulownia lines. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2016; 101:54-59. [PMID: 26854407 DOI: 10.1016/j.plaphy.2016.01.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 01/19/2016] [Accepted: 01/21/2016] [Indexed: 05/25/2023]
Abstract
The effects of soil salinity on the functional activity of photosynthetic apparatus and pigment composition of two Paulownia lines (Paulownia tomentosa x fortunei and Paulownia elongata x elongata) were investigated. PAM chlorophyll fluorescence measurements revealed that salinity leads to: (i) an increase of the photochemical quenching coefficient (qP) and the linear electron transport rate (ETR) in both lines of Paulownia, while the maximum quantum yield of the primary photochemistry of PSII in the dark adapted state (Fv/Fm) was unaffected; (ii) improved the efficiency of the photochemical energy conversion (ФPSII); (iii) an impact on the chlorophyll fluorescence decrease ratio (RFd), which correlates to the net CO2 assimilation rate; (iv) an impact on [Formula: see text] reoxidation. The analysis of the kinetics of P700(+) reduction upon turning off far-red irradiation revealed that salinization lead to a delay of the cyclic electron transport around PSI in both studied lines as the effect on this process is more pronounced in P. tomentosa x fortunei than in (in comparison with) P. elongata x elongata. The present experimental results suggested high salt tolerance of the studied lines Paulownia, but P. tomentosa x fortunei is more tolerant to salinity than P. elongata x elongata. Molecular mechanisms involved in the Paulownia response to the soil salinity are discussed.
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Affiliation(s)
- Martin Stefanov
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad.G. Bonchev Str. 21, Sofia 1113, Bulgaria
| | - Ekaterina Yotsova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad.G. Bonchev Str. 21, Sofia 1113, Bulgaria
| | - Georgi Rashkov
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad.G. Bonchev Str. 21, Sofia 1113, Bulgaria
| | - Katya Ivanova
- Faculty of Biology, University of Sofia, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria
| | - Yuliana Markovska
- Faculty of Biology, University of Sofia, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria
| | - Emilia L Apostolova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad.G. Bonchev Str. 21, Sofia 1113, Bulgaria.
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Yamamoto H, Takahashi S, Badger MR, Shikanai T. Artificial remodelling of alternative electron flow by flavodiiron proteins in Arabidopsis. NATURE PLANTS 2016; 2:16012. [PMID: 27249347 DOI: 10.1038/nplants.2016.12] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 01/20/2016] [Indexed: 05/19/2023]
Abstract
In photosynthesis, linear electron transport from water to nicotinamide adenine dinucleotide phosphate (NADP(+)) cannot satisfy the ATP/NADPH production stoichiometry required by the Calvin-Benson cycle. Cyclic electron transport (CET) around photosystem I (PSI) and pseudocyclic electron transport (pseudoCET) can produce ATP without the accumulation of NADPH. Flavodiiron proteins (Flv) are the main mediator of pseudoCET in photosynthetic organisms, spanning cyanobacteria to gymnosperms. However, their genes are not conserved in angiosperms. Here we explore the possibility of complementing CET with Flv-dependent pseudoCET in the angiosperm Arabidopsis thaliana. We introduced FlvA and FlvB genes from the moss Physcomitrella patens into both wild-type (WT) Arabidopsis and the proton gradient regulation 5 (pgr5) mutant, which is defective in the main pathway of CET. We measured rates of pseudoCET using membrane inlet mass spectrometry, along with several photosynthetic parameters. Flv expression significantly increased rates of pseudoCET in the mutant plants, particularly at high light intensities, and partially restored the photosynthetic phenotype. In WT plants, Flv did not compete with PGR5-dependent CET during steady-state photosynthesis, but did form a large electron sink in fluctuating light. We conclude that flavodiiron proteins can help to protect the photosystems in Arabidopsis under fluctuating light, even in the presence of CET.
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Affiliation(s)
- Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan
- CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076, Japan
| | - Shunichi Takahashi
- Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Murray R Badger
- Australian Research Council Center of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan
- CREST, Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076, Japan
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