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Colpo A, Demaria S, Boldrini P, Baldisserotto C, Pancaldi S, Ferroni L. Ultrastructural organization of the thylakoid system during the afternoon relocation of the giant chloroplast in Selaginella martensii Spring (Lycopodiophyta). PROTOPLASMA 2024; 261:143-159. [PMID: 37612526 PMCID: PMC10784399 DOI: 10.1007/s00709-023-01888-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 07/30/2023] [Indexed: 08/25/2023]
Abstract
Within the ancient vascular plant lineage known as lycophytes, many Selaginella species contain only one giant chloroplast in the upper epidermal cells of the leaf. In deep-shade species, such as S. martensii, the chloroplast is cup-shaped and the thylakoid system differentiates into an upper lamellar region and a lower granal region (bizonoplast). In this report, we describe the ultrastructural changes occurring in the giant chloroplast hosted in the epidermal cells of S. martensii during the daily relocation of the organelle. The process occurs in up to ca. 40% of the microphylls without the plants being exposed to high-light flecks. The relocated chloroplast loses its cup shape: first, it flattens laterally toward the radial cell wall and then assumes a more globular shape. The loss of the conical cell shape, the side-by-side lateral positioning of vacuole and chloroplast, and the extensive rearrangement of the thylakoid system to only granal cooperate in limiting light absorption. While the cup-shaped chloroplast emphasizes the light-harvesting capacity in the morning, the relocated chloroplast is suggested to support the renewal of the thylakoid system during the afternoon, including the recovery of photosystem II (PSII) from photoinhibition. The giant chloroplast repositioning is part of a complex reversible reshaping of the whole epidermal cell.
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Affiliation(s)
- Andrea Colpo
- Department of Environmental and Prevention Sciences, University of Ferrara, Corso Ercole I d'Este 32, 44121, Ferrara, Italy
| | - Sara Demaria
- Department of Environmental and Prevention Sciences, University of Ferrara, Corso Ercole I d'Este 32, 44121, Ferrara, Italy
| | - Paola Boldrini
- Center of Electron Microscopy, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy
| | - Costanza Baldisserotto
- Department of Environmental and Prevention Sciences, University of Ferrara, Corso Ercole I d'Este 32, 44121, Ferrara, Italy
| | - Simonetta Pancaldi
- Department of Environmental and Prevention Sciences, University of Ferrara, Corso Ercole I d'Este 32, 44121, Ferrara, Italy.
| | - Lorenzo Ferroni
- Department of Environmental and Prevention Sciences, University of Ferrara, Corso Ercole I d'Este 32, 44121, Ferrara, Italy.
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2
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Aronsson H, Solymosi K. Diversification of Plastid Structure and Function in Land Plants. Methods Mol Biol 2024; 2776:63-88. [PMID: 38502498 DOI: 10.1007/978-1-0716-3726-5_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
Plastids represent a largely diverse group of organelles in plant and algal cells that have several common features but also a broad spectrum of morphological, ultrastructural, biochemical, and physiological differences. Plastids and their structural and metabolic diversity significantly contribute to the functionality and developmental flexibility of the plant body throughout its lifetime. In addition to the multiple roles of given plastid types, this diversity is accomplished in some cases by interconversions between different plastids as a consequence of developmental and environmental signals that regulate plastid differentiation and specialization. In addition to basic plastid structural features, the most important plastid types, the newly characterized peculiar plastids, and future perspectives in plastid biology are also provided in this chapter.
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Affiliation(s)
- Henrik Aronsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Katalin Solymosi
- Department of Plant Anatomy, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary.
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3
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Ounoki R, Sóti A, Ünnep R, Sipka G, Sárvári É, Garab G, Solymosi K. Etioplasts are more susceptible to salinity stress than chloroplasts and photosynthetically active etio-chloroplasts of wheat (Triticum aestivum L.). PHYSIOLOGIA PLANTARUM 2023; 175:e14100. [PMID: 38148250 DOI: 10.1111/ppl.14100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/05/2023] [Accepted: 11/06/2023] [Indexed: 12/28/2023]
Abstract
High soil salinity is a global problem in agriculture that directly affects seed germination and the development of the seedlings sown deep in the soil. To study how salinity affected plastid ultrastructure, leaf segments of 11-day-old light- and dark-grown (etiolated) wheat (Triticum aestivum L. cv. Mv Béres) seedlings were floated on Hoagland solution, 600 mM KCl:NaCl (1:1) salt or isosmotic polyethylene glycol solution for 4 h in the dark. Light-grown seedlings were also treated in the light. The same treatments were also performed on etio-chloroplasts of etiolated seedlings greened for different time periods. Salt stress induced slight to strong changes in the relative chlorophyll content, photosynthetic activity, and organization of thylakoid complexes. Measurements of malondialdehyde contents and high-temperature thermoluminescence indicated significantly increased oxidative stress and lipid peroxidation under salt treatment, except for light-grown leaves treated in the dark. In chloroplasts of leaf segments treated in the light, slight shrinkage of grana (determined by transmission electron microscopy and small-angle neutron scattering) was observed, while a swelling of the (pro)thylakoid lumen was observed in etioplasts. Salt-induced swelling disappeared after the onset of photosynthesis after 4 h of greening. Osmotic stress caused no significant alterations in plastid structure and only mild changes in their activities, indicating that the swelling of the (pro)thylakoid lumen and the physiological effects of salinity are rather associated with the ionic component of salt stress. Our data indicate that etioplasts of dark-germinated wheat seedlings are the most sensitive to salt stress, especially at the early stages of their greening.
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Affiliation(s)
- Roumaissa Ounoki
- Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Adél Sóti
- Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Renáta Ünnep
- Neutron Spectroscopy Department, HUN-REN Centre for Energy Research, Budapest, Hungary
| | - Gábor Sipka
- Institute of Plant Biology, HUN-REN Biological Research Center, Szeged, Hungary
| | - Éva Sárvári
- Department of Plant Physiology and Molecular Plant Biology, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Győző Garab
- Institute of Plant Biology, HUN-REN Biological Research Center, Szeged, Hungary
- Department of Physics, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Katalin Solymosi
- Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary
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4
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Sóti A, Ounoki R, Kósa A, Mysliwa-Kurdziel B, Sárvári É, Solymosi K. Ionic, not the osmotic component, is responsible for the salinity-induced inhibition of greening in etiolated wheat (Triticum aestivum L. cv. Mv Béres) leaves: a comparative study. PLANTA 2023; 258:102. [PMID: 37861810 PMCID: PMC10589150 DOI: 10.1007/s00425-023-04255-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 09/27/2023] [Indexed: 10/21/2023]
Abstract
MAIN CONCLUSION Greening was partially (in 300 mM NaCl, CaCl2, 600 mM KNO3 or KCl) or fully inhibited (in 600 mM NaCl, NaNO3 or NaCl:KCl) by the ionic and not the osmotic component of salinity. Although high soil salinity is an increasing global problem, not much is known about how direct exposure to salinity affects etiolated leaves of seedlings germinating in the soil and then reaching the surface. We investigated the effect of various salt treatments on the greening process of leaves in 8- to 11-day-old etiolated wheat (Triticum aestivum L. Mv. Béres) seedlings. Etiolated leaf segments pre-treated on different salt (600 mM NaCl:KCl 1:1, 600 mM NaCl, 600 mM KCl, 600 mM NaNO3, 600 mM KNO3, 300 mM KCl, 300 mM NaCl or 300 mM CaCl2) or isosmotic polyethylene glycol 6000 (PEG) solutions for 1.5 h in the dark and then greened for 16 h on the same solutions were studied. Leaf segments greened on PEG (osmotic stress) or on 300 mM KCl had similar chloroplasts compared to control samples greened on Hoagland solution. Slightly slower development of chloroplast structure and function (photosynthetic activity) was observed in segments greened on 300 mM NaCl or CaCl2, 600 mM KNO3 or KCl. However, etioplast-to-chloroplast transformation and chlorophyll accumulation were fully inhibited and peculiar prothylakoid swelling occurred in segments greened on 600 mM NaCl, NaNO3 or NaCl:KCl (1:1) solutions. The data indicate that not the high osmolarity of the used salt solution, but its ions, especially Na+, had the strongest negative impact on these processes.
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Affiliation(s)
- Adél Sóti
- Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Roumaissa Ounoki
- Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Annamária Kósa
- Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Beata Mysliwa-Kurdziel
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Éva Sárvári
- Department of Plant Physiology and Molecular Plant Biology, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Katalin Solymosi
- Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Budapest, Hungary.
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Impact of Salinity on the Energy Transfer between Pigment-Protein Complexes in Photosynthetic Apparatus, Functions of the Oxygen-Evolving Complex and Photochemical Activities of Photosystem II and Photosystem I in Two Paulownia Lines. Int J Mol Sci 2023; 24:ijms24043108. [PMID: 36834517 PMCID: PMC9967322 DOI: 10.3390/ijms24043108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/26/2023] [Accepted: 01/31/2023] [Indexed: 02/08/2023] Open
Abstract
The present study shows the effect of salinity on the functions of thylakoid membranes from two hybrid lines of Paulownia: Paulownia tomentosa x fortunei and Paulownia elongate x elongata, grown in a Hoagland solution with two NaCl concentrations (100 and 150 mM) and different exposure times (10 and 25 days). We observed inhibition of the photochemical activities of photosystem I (DCPIH2 → MV) and photosystem II (H2O → BQ) only after the short treatment (10 days) with the higher NaCl concentration. Data also revealed alterations in the energy transfer between pigment-protein complexes (fluorescence emission ratios F735/F685 and F695/F685), the kinetic parameters of the oxygen-evolving reactions (initial S0-S1 state distribution, misses (α), double hits (β) and blocked centers (SB)). Moreover, the experimental results showed that after prolonged treatment with NaCl Paulownia tomentosa x fortunei adapted to the higher concentration of NaCl (150 mM), while this concentration is lethal for Paulownia elongata x elongata. This study demonstrated the relationship between the salt-induced inhibition of the photochemistry of both photosystems and the salt-induced changes in the energy transfer between the pigment-protein complexes and the alterations in the Mn cluster of the oxygen-evolving complex under salt stress.
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Heller WT. Small-Angle Neutron Scattering for Studying Lipid Bilayer Membranes. Biomolecules 2022; 12:1591. [PMID: 36358941 PMCID: PMC9687511 DOI: 10.3390/biom12111591] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/18/2022] [Accepted: 10/26/2022] [Indexed: 09/23/2023] Open
Abstract
Small-angle neutron scattering (SANS) is a powerful tool for studying biological membranes and model lipid bilayer membranes. The length scales probed by SANS, being from 1 nm to over 100 nm, are well-matched to the relevant length scales of the bilayer, particularly when it is in the form of a vesicle. However, it is the ability of SANS to differentiate between isotopes of hydrogen as well as the availability of deuterium labeled lipids that truly enable SANS to reveal details of membranes that are not accessible with the use of other techniques, such as small-angle X-ray scattering. In this work, an overview of the use of SANS for studying unilamellar lipid bilayer vesicles is presented. The technique is briefly presented, and the power of selective deuteration and contrast variation methods is discussed. Approaches to modeling SANS data from unilamellar lipid bilayer vesicles are presented. Finally, recent examples are discussed. While the emphasis is on studies of unilamellar vesicles, examples of the use of SANS to study intact cells are also presented.
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Affiliation(s)
- William T Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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7
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Mihailova G, Christov NK, Sárvári É, Solti Á, Hembrom R, Solymosi K, Keresztes Á, Velitchkova M, Popova AV, Simova-Stoilova L, Todorovska E, Georgieva K. Reactivation of the Photosynthetic Apparatus of Resurrection Plant Haberlea rhodopensis during the Early Phase of Recovery from Drought- and Freezing-Induced Desiccation. PLANTS 2022; 11:plants11172185. [PMID: 36079568 PMCID: PMC9460447 DOI: 10.3390/plants11172185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/16/2022] [Accepted: 08/18/2022] [Indexed: 11/16/2022]
Abstract
Haberlea rhodopensis is a unique desiccation-tolerant angiosperm that also survives winter frost. As, upon freezing temperatures, H. rhodopensis desiccates, the taxon is proposed to survive low temperature stress using its desiccation tolerance mechanisms. To reveal the validity of this hypothesis, we analyzed the structural alterations and organization of photosynthetic apparatus during the first hours of recovery after drought- and freezing-induced desiccation. The dynamics of the ultrastructure remodeling in the mesophyll cells and the restoration of the thylakoid membranes shared similarities independent of the reason for desiccation. Among the most obvious changes in thylakoid complexes, the proportion of the PSI-LHCII complex strongly increased around 70% relative water content (RWC), whereas the proportion of Lhc monomers decreased from the beginning of rehydration. We identified enhanced levels of cyt b6f complex proteins that contributed to the enhanced electron flow. The high abundance of proteins related to excitation energy dissipation, PsbS, Lhcb5, Lhcb6 and ELIPs, together with the increased content of dehydrins contributed to the preservation of cellular integrity. ELIP expression was maintained at high levels up to 9 h into recovery. Although the recovery processes from drought- and freezing-induced desiccation were found to be similar in progress and time scale, slight variations indicate that they are not identical.
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Affiliation(s)
- Gergana Mihailova
- Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Academic Georgi Bonchev Str., Bilding 21, 1113 Sofia, Bulgaria
| | - Nikolai K. Christov
- AgroBioInstitute, Agricultural Academy, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria
| | - Éva Sárvári
- Department of Plant Physiology and Molecular Plant Biology, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Pázmány Péter Sétány 1/C, H-1117 Budapest, Hungary
| | - Ádám Solti
- Department of Plant Physiology and Molecular Plant Biology, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Pázmány Péter Sétány 1/C, H-1117 Budapest, Hungary
| | - Richard Hembrom
- Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Pázmány Péter Sétány 1/C, H-1117 Budapest, Hungary
| | - Katalin Solymosi
- Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Pázmány Péter Sétány 1/C, H-1117 Budapest, Hungary
| | - Áron Keresztes
- Department of Plant Anatomy, Institute of Biology, Faculty of Science, ELTE Eötvös Loránd University, Pázmány Péter Sétány 1/C, H-1117 Budapest, Hungary
| | - Maya Velitchkova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Academic Georgi Bonchev Str., Bilding 21, 1113 Sofia, Bulgaria
| | - Antoaneta V. Popova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Academic Georgi Bonchev Str., Bilding 21, 1113 Sofia, Bulgaria
| | - Lyudmila Simova-Stoilova
- Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Academic Georgi Bonchev Str., Bilding 21, 1113 Sofia, Bulgaria
| | - Elena Todorovska
- AgroBioInstitute, Agricultural Academy, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria
| | - Katya Georgieva
- Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Academic Georgi Bonchev Str., Bilding 21, 1113 Sofia, Bulgaria
- Correspondence: or ; Tel.: +359-2-979-2620
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8
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Martel A, Gabel F. Time-resolved small-angle neutron scattering (TR-SANS) for structural biology of dynamic systems: Principles, recent developments, and practical guidelines. Methods Enzymol 2022; 677:263-290. [DOI: 10.1016/bs.mie.2022.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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9
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Nagy G, Garab G. Neutron scattering in photosynthesis research: recent advances and perspectives for testing crop plants. PHOTOSYNTHESIS RESEARCH 2021; 150:41-49. [PMID: 32488447 PMCID: PMC8556207 DOI: 10.1007/s11120-020-00763-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 05/25/2020] [Indexed: 05/05/2023]
Abstract
The photosynthetic performance of crop plants under a variety of environmental factors and stress conditions, at the fundamental level, depends largely on the organization and structural flexibility of thylakoid membranes. These highly organized membranes accommodate virtually all protein complexes and additional compounds carrying out the light reactions of photosynthesis. Most regulatory mechanisms fine-tuning the photosynthetic functions affect the organization of thylakoid membranes at different levels of the structural complexity. In order to monitor these reorganizations, non-invasive techniques are of special value. On the mesoscopic scale, small-angle neutron scattering (SANS) has been shown to deliver statistically and spatially averaged information on the periodic organization of the thylakoid membranes in vivo and/or, in isolated thylakoids, under physiologically relevant conditions, without fixation or staining. More importantly, SANS investigations have revealed rapid reversible reorganizations on the timescale of several seconds and minutes. In this paper, we give a short introduction into the basics of SANS technique, advantages and limitations, and briefly overview recent advances and potential applications of this technique in the physiology and biotechnology of crop plants. We also discuss future perspectives of neutron crystallography and different neutron scattering techniques, which are anticipated to become more accessible and of more use in photosynthesis research at new facilities with higher fluxes and innovative instrumentation.
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Affiliation(s)
- Gergely Nagy
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA.
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, POB 49, 1525, Budapest, Hungary.
| | - Győző Garab
- Institute of Plant Biology, Biological Research Centre, POB 521, 6701, Szeged, Hungary.
- Department of Physics, Faculty of Science, Ostrava University, Chittussiho 10, Ostrava - Slezská, 710 0, Ostrava, Czech Republic.
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Kanna SD, Domonkos I, Kóbori TO, Dergez Á, Böde K, Nagyapáti S, Zsiros O, Ünnep R, Nagy G, Garab G, Szilák L, Solymosi K, Kovács L, Ughy B. Salt Stress Induces Paramylon Accumulation and Fine-Tuning of the Macro-Organization of Thylakoid Membranes in Euglena gracilis Cells. FRONTIERS IN PLANT SCIENCE 2021; 12:725699. [PMID: 34868111 PMCID: PMC8636990 DOI: 10.3389/fpls.2021.725699] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/28/2021] [Indexed: 05/13/2023]
Abstract
The effects of salt stress condition on the growth, morphology, photosynthetic performance, and paramylon content were examined in the mixotrophic, unicellular, flagellate Euglena gracilis. We found that salt stress negatively influenced cell growth, accompanied by a decrease in chlorophyll (Chl) content. Circular dichroism (CD) spectroscopy revealed the changes in the macro-organization of pigment-protein complexes due to salt treatment, while the small-angle neutron scattering (SANS) investigations suggested a reduction in the thylakoid stacking, an effect confirmed by the transmission electron microscopy (TEM). At the same time, the analysis of the thylakoid membrane complexes using native-polyacrylamide gel electrophoresis (PAGE) revealed no significant change in the composition of supercomplexes of the photosynthetic apparatus. Salt stress did not substantially affect the photosynthetic activity, as reflected by the fact that Chl fluorescence yield, electron transport rate (ETR), and energy transfer between the photosystems did not change considerably in the salt-grown cells. We have observed notable increases in the carotenoid-to-Chl ratio and the accumulation of paramylon in the salt-treated cells. We propose that the accumulation of storage polysaccharides and changes in the pigment composition and thylakoid membrane organization help the adaptation of E. gracilis cells to salt stress and contribute to the maintenance of cellular processes under stress conditions.
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Affiliation(s)
- Sai Divya Kanna
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
- Doctoral School of Biology, University of Szeged, Szeged, Hungary
| | - Ildikó Domonkos
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Tímea Ottília Kóbori
- Doctoral School of Biology, University of Szeged, Szeged, Hungary
- Division for Biotechnology, Bay Zoltán Nonprofit Ltd. for Applied Research, Szeged, Hungary
| | - Ágnes Dergez
- Division for Biotechnology, Bay Zoltán Nonprofit Ltd. for Applied Research, Szeged, Hungary
| | - Kinga Böde
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
- Doctoral School of Biology, University of Szeged, Szeged, Hungary
| | - Sarolta Nagyapáti
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
- Doctoral School of Biology, University of Szeged, Szeged, Hungary
| | - Ottó Zsiros
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Renáta Ünnep
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Eötvös Loránd Research Network, Budapest, Hungary
| | - Gergely Nagy
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Eötvös Loránd Research Network, Budapest, Hungary
- European Spallation Source ESS ERIC, Lund, Sweden
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen PSI, Villigen, Switzerland
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Gyözö Garab
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
- Faculty of Science, University of Ostrava, Ostrava, Czechia
| | | | - Katalin Solymosi
- Department of Plant Anatomy, ELTE Eötvös Loránd University, Budapest, Hungary
| | - László Kovács
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Bettina Ughy
- Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
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11
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Rondelli V, Koutsioubas A, Pršić J, Deboever E, Crowet JM, Lins L, Deleu M. Sitosterol and glucosylceramide cooperative transversal and lateral uneven distribution in plant membranes. Sci Rep 2021; 11:21618. [PMID: 34732753 PMCID: PMC8566578 DOI: 10.1038/s41598-021-00696-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 10/05/2021] [Indexed: 11/13/2022] Open
Abstract
The properties of biomembranes depend on the presence, local structure and relative distribution assumed by the thousands of components it is made of. As for animal cells, plant membranes have been demonstrated to be organized in subdomains with different persistence lengths and times. In plant cells, sitosterol has been demonstrated to confer to phospholipid membranes a more ordered structure while among lipids, glycosphingolipids are claimed to form rafts where they tightly pack with sterols. Glucosylceramides are glycosphingolipids involved in plant signalling and are essential for viability of cells and whole plant. The glucosylceramide-sitosterol structural coupling within PLPC membranes is here investigated by Langmuir films, in silico simulations and neutron reflectometry, unveiling that a strong direct interaction between the two molecules exists and governs their lateral and transversal distribution within membrane leaflets. The understanding of the driving forces governing specific molecules clustering and segregation in subdomains, such as glucosylceramide and sitosterol, have an impact on the mechanical properties of biomembranes and could reflect in the other membrane molecules partitioning and activity.
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Affiliation(s)
- V Rondelli
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milano, Italy.
| | - A Koutsioubas
- Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, Forschungszentrum Jülich GmbH, Garching, Germany.
| | - J Pršić
- Microbial Processes and Interactions Laboratory (MiPI), TERRA Research Center, Gembloux Agro-Bio Tech, Université de Liège, Gembloux, Belgium
| | - E Deboever
- Laboratoire de Biophysique Moléculaire aux Interfaces, Structure Fédérative de Recherche Condorcet, TERRA Research Center, Gembloux Agro-Bio Tech, Université de Liège, Gembloux, Belgium.,Laboratory of Natural Molecules Chemistry, Gembloux Agro-Bio Tech, University of Liège, 2, Passage des Déportés, 5030, Gembloux, Belgium.,FytoFend S.A., rue Georges Legrand, 6, 5032, Isnes, Belgium
| | - J M Crowet
- Université de Reims Champagne-Ardenne, UFR Sciences Exactes et Naturelles, Reims, France
| | - L Lins
- Laboratoire de Biophysique Moléculaire aux Interfaces, Structure Fédérative de Recherche Condorcet, TERRA Research Center, Gembloux Agro-Bio Tech, Université de Liège, Gembloux, Belgium
| | - M Deleu
- Laboratoire de Biophysique Moléculaire aux Interfaces, Structure Fédérative de Recherche Condorcet, TERRA Research Center, Gembloux Agro-Bio Tech, Université de Liège, Gembloux, Belgium.
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Ounoki R, Ágh F, Hembrom R, Ünnep R, Szögi-Tatár B, Böszörményi A, Solymosi K. Salt Stress Affects Plastid Ultrastructure and Photosynthetic Activity but Not the Essential Oil Composition in Spearmint ( Mentha spicata L. var. crispa "Moroccan"). FRONTIERS IN PLANT SCIENCE 2021; 12:739467. [PMID: 34777420 PMCID: PMC8586547 DOI: 10.3389/fpls.2021.739467] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
High levels of soil salinity affect plant growth, reproduction, water and ion uptake, and plant metabolism in a complex manner. In this work, the effect of salt stress on vegetative growth, photosynthetic activity, and chloroplast ultrastructure of spearmint (Mentha spicata L. var. crispa "Moroccan") was investigated. After 2 weeks of low concentration treatments (5, 25, and 50 mM NaCl) of freshly cut shoots, we observed that the stem-derived adventitious root formation, which is a major mean for vegetative reproduction among mints, was completely inhibited at 50 mM NaCl concentration. One-week-long, high concentration (150 mM NaCl) salt stress, and isosmotic polyethylene glycol (PEG) 6000 treatments were compared in intact (rooted) plants and freshly cut, i.e., rootless shoots. Our data showed that roots have an important role in mitigating the deleterious effects of both the osmotic (PEG treatment) and specific ionic components of high salinity stress. At 50 mM NaCl or above, the ionic component of salt stress caused strong and irreversible physiological alterations. The effects include a decrease in relative water content, the maximal and actual quantum efficiency of photosystem II, relative chlorophyll content, as well as disorganization of the native chlorophyll-protein complexes as revealed by 77 K fluorescence spectroscopy. In addition, important ultrastructural damage was observed by transmission electron microscopy such as the swelling of the thylakoid lumen at 50 mM NaCl treatment. Interestingly, in almost fully dry leaf regions and leaves, granum structure was relatively well retained, however, their disorganization occurred in leaf chloroplasts of rooted spearmint treated with 150 mM NaCl. This loss of granum regularity was also confirmed in the leaves of these plants using small-angle neutron scattering measurements of intact leaves of 150 mM NaCl-stressed rooted plants. At the same time, solid-phase microextraction of spearmint leaves followed by gas chromatography and mass spectrometry (GC/MS) analyses revealed that the essential oil composition of spearmint was unaffected by the treatments applied in this work. Taken together, the used spearmint cultivar tolerates low salinity levels. However, at 50 mM NaCl concentration and above, the ionic components of the stress strongly inhibit adventitious root formation and thus their clonal propagation, and severely damage the photosynthetic apparatus.
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Affiliation(s)
- Roumaissa Ounoki
- Department of Plant Anatomy, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Ferenc Ágh
- Department of Plant Anatomy, ELTE Eötvös Loránd University, Budapest, Hungary
- Department of Pharmacognosy, Semmelweis University, Budapest, Hungary
| | - Richard Hembrom
- Department of Plant Anatomy, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Renáta Ünnep
- Neutron Spectroscopy Department, Center for Energy Research, Budapest, Hungary
| | | | | | - Katalin Solymosi
- Department of Plant Anatomy, ELTE Eötvös Loránd University, Budapest, Hungary
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Stefanov MA, Rashkov GD, Yotsova EK, Borisova PB, Dobrikova AG, Apostolova EL. Different Sensitivity Levels of the Photosynthetic Apparatus in Zea mays L. and Sorghum bicolor L. under Salt Stress. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10071469. [PMID: 34371672 PMCID: PMC8309219 DOI: 10.3390/plants10071469] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 07/09/2021] [Accepted: 07/13/2021] [Indexed: 05/17/2023]
Abstract
The impacts of different NaCl concentrations (0-250 mM) on the photosynthesis of new hybrid lines of maize (Zea mays L. Kerala) and sorghum (Sorghum bicolor L. Shamal) were investigated. Salt-induced changes in the functions of photosynthetic apparatus were assessed using chlorophyll a fluorescence (PAM and OJIP test) and P700 photooxidation. Greater differences between the studied species in response to salinization were observed at 150 mM and 200 mM NaCl. The data revealed the stronger influence of maize in comparison to sorghum on the amount of closed PSII centers (1-qp) and their efficiency (Φexc), as well as on the effective quantum yield of the photochemical energy conversion of PSII (ΦPSII). Changes in the effective antenna size of PSII (ABS/RC), the electron flux per active reaction center (REo/RC) and the electron transport flux further QA (ETo/RC) were also registered. These changes in primary PSII photochemistry influenced the electron transport rate (ETR) and photosynthetic rate (parameter RFd), with the impacts being stronger in maize than sorghum. Moreover, the lowering of the electron transport rate from QA to the PSI end electron acceptors (REo/RC) and the probability of their reduction (φRo) altered the PSI photochemical activity, which influenced photooxidation of P700 and its decay kinetics. The pigment content and stress markers of oxidative damage were also determined. The data revealed a better salt tolerance of sorghum than maize, associated with the structural alterations in the photosynthetic membranes and the stimulation of the cyclic electron flow around PSI at higher NaCl concentrations. The relationships between the decreased pigment content, increased levels of stress markers and different inhibition levels of the function of both photosystems are discussed.
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14
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Jakubauskas D, Mortensen K, Jensen PE, Kirkensgaard JJK. Small-Angle X-Ray and Neutron Scattering on Photosynthetic Membranes. Front Chem 2021; 9:631370. [PMID: 33954157 PMCID: PMC8090863 DOI: 10.3389/fchem.2021.631370] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 02/01/2021] [Indexed: 11/26/2022] Open
Abstract
Ultrastructural membrane arrangements in living cells and their dynamic remodeling in response to environmental changes remain an area of active research but are also subject to large uncertainty. The use of noninvasive methods such as X-ray and neutron scattering provides an attractive complimentary source of information to direct imaging because in vivo systems can be probed in near-natural conditions. However, without solid underlying structural modeling to properly interpret the indirect information extracted, scattering provides at best qualitative information and at worst direct misinterpretations. Here we review the current state of small-angle scattering applied to photosynthetic membrane systems with particular focus on data interpretation and modeling.
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Affiliation(s)
- Dainius Jakubauskas
- X-ray and Neutron Science, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Kell Mortensen
- X-ray and Neutron Science, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Poul Erik Jensen
- Department of Food Science, University of Copenhagen, Copenhagen, Denmark
| | - Jacob J. K. Kirkensgaard
- X-ray and Neutron Science, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
- Department of Food Science, University of Copenhagen, Copenhagen, Denmark
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15
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Li M, Mukhopadhyay R, Svoboda V, Oung HMO, Mullendore DL, Kirchhoff H. Measuring the dynamic response of the thylakoid architecture in plant leaves by electron microscopy. PLANT DIRECT 2020; 4:e00280. [PMID: 33195966 PMCID: PMC7644818 DOI: 10.1002/pld3.280] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 09/15/2020] [Accepted: 09/29/2020] [Indexed: 05/19/2023]
Abstract
UNLABELLED The performance of the photosynthesis machinery in plants, including light harvesting, electron transport, and protein repair, is controlled by structural changes in the thylakoid membrane system inside the chloroplasts. In particular, the structure of the stacked grana area of thylakoid membranes is highly dynamic, changing in response to different environmental cues such as light intensity. For example, the aqueous thylakoid lumen enclosed by thylakoid membranes in grana has been documented to swell in the presence of light. However, light-induced alteration of the stromal gap in the stacked grana (partition gap) and of the unstacked stroma lamellae has not been well characterized. Light-induced changes in the entire thylakoid membrane system, including the lumen in both stacked and unstacked domains as well as the partition gap, are presented here, and the functional implications are discussed. This structural analysis was made possible by development of a robust semi-automated image analysis method combined with optimized plant tissue fixation techniques for transmission electron microscopy generating quantitative structural results for the analysis of thylakoid ultrastructure. SIGNIFICANCE STATEMENT A methodical pipeline ranging from optimized leaf tissue preparation for electron microscopy to quantitative image analysis was established. This methodical development was employed to study details of light-induced changes in the plant thylakoid ultrastructure. It was found that the lumen of the entire thylakoid system (stacked and unstacked domains) undergoes light-induced swelling, whereas adjacent membranes on the stroma side in stacked grana thylakoid approach each other.
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Affiliation(s)
- Meng Li
- Institute of Biological ChemistryWashington State UniversityPullmanWAUSA
- Present address:
School of OceanographyUniversity of WashingtonSeattleWAUSA
| | - Roma Mukhopadhyay
- Institute of Biological ChemistryWashington State UniversityPullmanWAUSA
| | - Václav Svoboda
- Institute of Biological ChemistryWashington State UniversityPullmanWAUSA
| | | | | | - Helmut Kirchhoff
- Institute of Biological ChemistryWashington State UniversityPullmanWAUSA
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16
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Ünnep R, Paul S, Zsiros O, Kovács L, Székely NK, Steinbach G, Appavou MS, Porcar L, Holzwarth AR, Garab G, Nagy G. Thylakoid membrane reorganizations revealed by small-angle neutron scattering of Monstera deliciosa leaves associated with non-photochemical quenching. Open Biol 2020; 10:200144. [PMID: 32931722 PMCID: PMC7536078 DOI: 10.1098/rsob.200144] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/14/2020] [Indexed: 12/14/2022] Open
Abstract
Non-photochemical quenching (NPQ) is an important photoprotective mechanism in plants and algae. Although the process is extensively studied, little is known about its relationship with ultrastructural changes of the thylakoid membranes. In order to better understand this relationship, we studied the effects of illumination on the organization of thylakoid membranes in Monstera deliciosa leaves. This evergreen species is known to exhibit very large NPQ and to possess giant grana with dozens of stacked thylakoids. It is thus ideally suited for small-angle neutron scattering measurements (SANS)-a non-invasive technique, which is capable of providing spatially and statistically averaged information on the periodicity of the thylakoid membranes and their rapid reorganizations in vivo. We show that NPQ-inducing illumination causes a strong decrease in the periodic order of granum thylakoid membranes. Development of NPQ and light-induced ultrastructural changes, as well as the relaxation processes, follow similar kinetic patterns. Surprisingly, whereas NPQ is suppressed by diuron, it impedes only the relaxation of the structural changes and not its formation, suggesting that structural changes do not cause but enable NPQ. We also demonstrate that the diminishment of SANS peak does not originate from light-induced redistribution and reorientation of chloroplasts inside the cells.
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Affiliation(s)
- Renáta Ünnep
- Neutron Spectroscopy Department, Centre for Energy Research, H-1121 Budapest, Konkoly-Thege Miklós út 29-33, Hungary
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Suman Paul
- Max-Planck-Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim a.d. Ruhr, Germany
| | - Ottó Zsiros
- Biological Research Centre, Institute of Plant Biology, 6726 Szeged, Hungary
| | - László Kovács
- Biological Research Centre, Institute of Plant Biology, 6726 Szeged, Hungary
| | - Noémi K. Székely
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, 85748 Garching, Germany
| | - Gábor Steinbach
- Biological Research Centre, Institute of Biophysics, Temesvári körút 62, 6726 Szeged, Hungary
| | - Marie-Sousai Appavou
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, 85748 Garching, Germany
| | - Lionel Porcar
- Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9, France
| | - Alfred R. Holzwarth
- Max-Planck-Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim a.d. Ruhr, Germany
| | - Győző Garab
- Biological Research Centre, Institute of Plant Biology, 6726 Szeged, Hungary
- Department of Physics, Faculty of Science, Ostrava University, Chittussiho 10, 710 00 Ostrava, Czech Republic
| | - Gergely Nagy
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- European Spallation Source ESS ERIC, PO Box 176, 221 00 Lund, Sweden
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, 1121 Budapest, Hungary
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17
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Wilhelm C, Goss R, Garab G. The fluid-mosaic membrane theory in the context of photosynthetic membranes: Is the thylakoid membrane more like a mixed crystal or like a fluid? JOURNAL OF PLANT PHYSIOLOGY 2020; 252:153246. [PMID: 32777580 DOI: 10.1016/j.jplph.2020.153246] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/14/2020] [Accepted: 07/17/2020] [Indexed: 06/11/2023]
Abstract
Since the publication of the fluid-mosaic membrane theory by Singer and Nicolson in 1972 generations of scientists have adopted this fascinating concept for all biological membranes. Assuming the membrane as a fluid implies that the components embedded in the lipid bilayer can freely diffuse like swimmers in a water body. During the detailed biochemical analysis of the thylakoid protein components of chloroplasts from higher plants and algae, in the '80 s and '90 s it became clear that photosynthetic membranes are not homogeneous either in the vertical or the lateral directions. The lateral heterogeneity became obvious by the differentiation of grana and stroma thylakoids, but also the margins have been identified with a highly specific protein pattern. Further refinement of the fluid mosaic model was needed to take into account the presence of non-bilayer lipids, which are the most abundant lipids in all energy-converting membranes, and the polymorphism of lipid phases, which has also been documented in thylakoid membranes. These observations lead to the question, how mobile the components are in the lipid phase and how this ordering is made and maintained and how these features might be correlated with the non-bilayer propensity of the membrane lipids. Assuming instead of free diffusion, a "controlled neighborhood" replaced the model of fluidity by the model of a "mixed crystal structure". In this review we describe why basic photosynthetic regulation mechanisms depend on arrays of crystal-like lipid-protein macro-assemblies. The mechanisms which define the ordering in macrodomains are still not completely clear, but some recent experiments give an idea how this fascinating order is produced, adopted and maintained. We use the operation of the xanthophyll cycle as a rather well understood model challenging and complementing the standard Singer-Nicolson model via assigning special roles to non-bilayer lipids and non-lamellar lipid phases in the structure and function of thylakoid membranes.
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Affiliation(s)
- Christian Wilhelm
- Leipzig University, Institute of Biology, SenProf Algal Biotechnology, Permoserstr. 15, 04315, Leipzig, Germany; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, D-04103, Leipzig, Germany.
| | - Reimund Goss
- Leipzig University, Institute of Biology, Department of Plant Physiology, Johannisallee 21-23, D-04103, Leipzig, Germany
| | - Gyözö Garab
- Biological Research Centre, Institute of Plant Biology, Temesvári körút 62, H-6726, Szeged, Hungary; University of Ostrava, Department of Physics, Faculty of Science, Chittussiho 10, CZ-710 00, Ostrava, Slezská Ostrava, Czech Republic
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18
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19
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Ultrastructural modeling of small angle scattering from photosynthetic membranes. Sci Rep 2019; 9:19405. [PMID: 31852917 PMCID: PMC6920412 DOI: 10.1038/s41598-019-55423-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 10/04/2019] [Indexed: 11/08/2022] Open
Abstract
The last decade has seen a range of studies using non-invasive neutron and X-ray techniques to probe the ultrastructure of a variety of photosynthetic membrane systems. A common denominator in this work is the lack of an explicitly formulated underlying structural model, ultimately leading to ambiguity in the data interpretation. Here we formulate and implement a full mathematical model of the scattering from a stacked double bilayer membrane system taking instrumental resolution and polydispersity into account. We validate our model by direct simulation of scattering patterns from 3D structural models. Most importantly, we demonstrate that the full scattering curves from three structurally typical cyanobacterial thylakoid membrane systems measured in vivo can all be described within this framework. The model provides realistic estimates of key structural parameters in the thylakoid membrane, in particular the overall stacking distance and how this is divided between membranes, lumen and cytoplasmic liquid. Finally, from fitted scattering length densities it becomes clear that the protein content in the inner lumen has to be lower than in the outer cytoplasmic liquid and we extract the first quantitative measure of the luminal protein content in a living cyanobacteria.
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20
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Macroorganisation and flexibility of thylakoid membranes. Biochem J 2019; 476:2981-3018. [DOI: 10.1042/bcj20190080] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 09/19/2019] [Accepted: 10/03/2019] [Indexed: 02/07/2023]
Abstract
Abstract
The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.
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21
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Kowalewska Ł, Bykowski M, Mostowska A. Spatial organization of thylakoid network in higher plants. BOTANY LETTERS 2019. [PMID: 0 DOI: 10.1080/23818107.2019.1619195] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Affiliation(s)
- Łucja Kowalewska
- Department of Plant Anatomy and Cytology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Michał Bykowski
- Department of Plant Anatomy and Cytology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Agnieszka Mostowska
- Department of Plant Anatomy and Cytology, Faculty of Biology, University of Warsaw, Warsaw, Poland
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22
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Johnson MP, Wientjes E. The relevance of dynamic thylakoid organisation to photosynthetic regulation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1861:148039. [PMID: 31228404 DOI: 10.1016/j.bbabio.2019.06.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 06/14/2019] [Accepted: 06/15/2019] [Indexed: 12/11/2022]
Abstract
The higher plant chloroplast thylakoid membrane system performs the light-dependent reactions of photosynthesis. These provide the ATP and NADPH required for the fixation of CO2 into biomass by the Calvin-Benson cycle and a range of other metabolic reactions in the stroma. Land plants are frequently challenged by fluctuations in their environment, such as light, nutrient and water availability, which can create a mismatch between the amounts of ATP and NADPH produced and the amounts required by the downstream metabolism. Left unchecked, such imbalances can lead to the production of reactive oxygen species that damage the plant and harm productivity. Fortunately, plants have evolved a complex range of regulatory processes to avoid or minimize such deleterious effects by controlling the efficiency of light harvesting and electron transfer in the thylakoid membrane. Generally the regulation of the light reactions has been studied and conceptualised at the microscopic level of protein-protein and protein-ligand interactions, however in recent years dynamic changes in the thylakoid macrostructure itself have been recognised to play a significant role in regulating light harvesting and electron transfer. Here we review the evidence for the involvement of macrostructural changes in photosynthetic regulation and review the techniques that brought this evidence to light.
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Affiliation(s)
- Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom.
| | - Emilie Wientjes
- Laboratory of Biophysics, Wageningen University, Stippeneng 4, 6708 WE Wageningen, the Netherlands
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23
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Ughy B, Karlický V, Dlouhý O, Javornik U, Materová Z, Zsiros O, Šket P, Plavec J, Špunda V, Garab G. Lipid-polymorphism of plant thylakoid membranes. Enhanced non-bilayer lipid phases associated with increased membrane permeability. PHYSIOLOGIA PLANTARUM 2019; 166:278-287. [PMID: 30666653 DOI: 10.1111/ppl.12929] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/17/2019] [Accepted: 01/17/2019] [Indexed: 06/09/2023]
Abstract
Earlier experiments, using 31 P-NMR and time-resolved merocyanine fluorescence spectroscopy, have shown that isolated intact, fully functional plant thylakoid membranes, in addition to the bilayer phase, contain three non-bilayer (or non-lamellar) lipid phases. It has also been shown that the lipid polymorphism of thylakoid membranes can be characterized by remarkable plasticity, i.e. by significant variations in 31 P-NMR signatures. However, changes in the lipid-phase behaviour of thylakoids could not be assigned to changes in the overall membrane organization and the photosynthetic activity, as tested by circular dichroism and 77 K fluorescence emission spectroscopy and the magnitude of the variable fluorescence of photosystem II, which all showed only marginal variations. In this work, we investigated in more detail the temporal stability of the different lipid phases by recording 31 P-NMR spectra on isolated thylakoid membranes that were suspended in sorbitol- or NaCl-based media. We observed, at 5°C during 8 h in the dark, substantial gradual enhancement of the isotropic lipid phases and diminishment of the bilayer phase in the sorbitol-based medium. These changes compared well with the gradually increasing membrane permeability, as testified by the gradual acceleration of the decay of flash-induced electrochromic absorption changes and characteristic changes in the kinetics of fast chlorophyll a-fluorescence transients; all variations were much less pronounced in the NaCl-based medium. These observations suggest that non-bilayer lipids and non-lamellar lipid phases play significant roles in the structural dynamics and functional plasticity of thylakoid membranes.
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Affiliation(s)
- Bettina Ughy
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Szeged H-6726, Hungary
| | - Václav Karlický
- Department of Physics, Faculty of Science, University of Ostrava, Ostrava CZ-710 00, Czech Republic
- Global Change Research Institute, Czech Academy of Sciences, Brno 603 00, Czech Republic
| | - Ondřej Dlouhý
- Department of Physics, Faculty of Science, University of Ostrava, Ostrava CZ-710 00, Czech Republic
| | - Uroš Javornik
- Slovenian NMR Center, National Institute of Chemistry, Ljubljana, Slovenia
| | - Zuzana Materová
- Department of Physics, Faculty of Science, University of Ostrava, Ostrava CZ-710 00, Czech Republic
| | - Ottó Zsiros
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Szeged H-6726, Hungary
| | - Primož Šket
- Slovenian NMR Center, National Institute of Chemistry, Ljubljana, Slovenia
- EN-FIST Center of Excellence, Ljubljana, Slovenia
| | - Janez Plavec
- Slovenian NMR Center, National Institute of Chemistry, Ljubljana, Slovenia
- EN-FIST Center of Excellence, Ljubljana, Slovenia
- Faculty of Chemistry and Chemical Technology, Ljubljana, Slovenia
| | - Vladimír Špunda
- Department of Physics, Faculty of Science, University of Ostrava, Ostrava CZ-710 00, Czech Republic
- Global Change Research Institute, Czech Academy of Sciences, Brno 603 00, Czech Republic
| | - Győző Garab
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Szeged H-6726, Hungary
- Department of Physics, Faculty of Science, University of Ostrava, Ostrava CZ-710 00, Czech Republic
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24
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Zsiros O, Nagy V, Párducz Á, Nagy G, Ünnep R, El-Ramady H, Prokisch J, Lisztes-Szabó Z, Fári M, Csajbók J, Tóth SZ, Garab G, Domokos-Szabolcsy É. Effects of selenate and red Se-nanoparticles on the photosynthetic apparatus of Nicotiana tabacum. PHOTOSYNTHESIS RESEARCH 2019; 139:449-460. [PMID: 30374728 DOI: 10.1007/s11120-018-0599-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 10/17/2018] [Indexed: 05/24/2023]
Abstract
Selenium (Se) is a natural trace element, which shifts its action in a relatively narrow concentration range from nutritional role to toxicity. Although it has been well established that in plants chloroplasts are among the primary targets, the mechanism of toxicity on photosynthesis is not well understood. Here, we compared selenate and red-allotrope elemental selenium nanoparticles (red nanoSe) in in vitro tobacco cultures to investigate their effects on the structure and functions of the photosynthetic machinery. Selenate at 10 mg/L concentration retarded plant growth; it also led to a decreased chlorophyll content, accompanied with an increase in the carotenoid-to-chlorophyll ratio. Structural examinations of the photosynthetic machinery, using electron microscopy, small-angle neutron scattering and circular dichroism spectroscopy, revealed significant perturbation in the macro-organization of the pigment-protein complexes and sizeable shrinkage in the repeat distance of granum thylakoid membranes. As shown by chlorophyll a fluorescence transient measurements, these changes in the ultrastructure were associated with a significantly diminished photosystem II activity and a reduced performance of the photosynthetic electron transport, and an enhanced capability of non-photochemical quenching. These changes in the structure and function of the photosynthetic apparatus explain, at least in part, the retarded growth of plantlets in the presence of 10 mg/L selenate. In contrast, red nanoSe, even at 100 mg/L and selenate at 1 mg/L, exerted no negative effect on the growth of plantlets and affected only marginally the thylakoid membrane ultrastructure and the photosynthetic functions.
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Affiliation(s)
- Ottó Zsiros
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, POB 521, Szeged, 6701, Hungary
| | - Valéria Nagy
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, POB 521, Szeged, 6701, Hungary
| | - Árpád Párducz
- Institute of Biophysics, Biological Research Center, Hungarian Academy of Sciences, POB 521, Szeged, 6701, Hungary
| | - Gergely Nagy
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, POB 521, Szeged, 6701, Hungary
- Laboratory for Neutron Scattering, Paul Scherrer Institute, 5232, Villigen PSI, Switzerland
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, POB 49, Budapest, 1525, Hungary
| | - Renáta Ünnep
- Laboratory for Neutron Scattering, Paul Scherrer Institute, 5232, Villigen PSI, Switzerland
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, POB 49, Budapest, 1525, Hungary
| | - Hassan El-Ramady
- Department of Soil and Water Sciences, Faculty of Agriculture, Kafrelsheikh Uni, 33516, Kafr El-Sheikh, Egypt
- Department of Agricultural Botany, Plant Physiology and Biotechnology, University of Debrecen, Egyetem ter 1, Debrecen, 4032, Hungary
| | - József Prokisch
- Bio- and Environmental Enegetics Inst., Nano Food Lab, Debrecen University, Boszormenyi 138, Debrecen, 4032, Hungary
| | - Zsuzsa Lisztes-Szabó
- Isotope Climatology and Environmental Research Centre, Institute for Nuclear Research, Hungarian Academy of Sciences, Debrecen, 4026, Hungary
| | - Miklós Fári
- Department of Agricultural Botany, Plant Physiology and Biotechnology, University of Debrecen, Egyetem ter 1, Debrecen, 4032, Hungary
| | - József Csajbók
- Department of Crop Production and Applied Ecology, University of Debrecen, Boszormenyi 138, Debrecen, 4032, Hungary
| | - Szilvia Zita Tóth
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, POB 521, Szeged, 6701, Hungary
| | - Győző Garab
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, POB 521, Szeged, 6701, Hungary
- Department of Physics, Faculty of Science, Ostrava University, Chittussiho 10, 710 0, Ostrava - Slezská Ostrava, Czech Republic
| | - Éva Domokos-Szabolcsy
- Department of Agricultural Botany, Plant Physiology and Biotechnology, University of Debrecen, Egyetem ter 1, Debrecen, 4032, Hungary.
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Niewiadomska E, Brückner K, Mulisch M, Kruk J, Orzechowska A, Pilarska M, Luchowski R, Gruszecki WI, Krupinska K. Lack of tocopherols influences the PSII antenna and the functioning of photosystems under low light. JOURNAL OF PLANT PHYSIOLOGY 2018; 223:57-64. [PMID: 29499454 DOI: 10.1016/j.jplph.2018.02.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 02/02/2018] [Accepted: 02/04/2018] [Indexed: 06/08/2023]
Abstract
As tocopherols are expected to protect PSII against toxic singlet oxygen it is surprising that the null tocopherol mutant vte1 has been reported to show only a weak enhancement of photosystem II photoinhibition under high irradiance. Based on the view that singlet oxygen is formed also in unstressed conditions, such as low light (LL), we hypothesized that some defense strategies are activated in vte1 in these light conditions. In support for that we noted several symptoms of stress at PSII in the mutant under LL, by means of parameters of fast and slow kinetics of chlorophyll fluorescence and of changes in the relative contribution of PSII antenna in comparison to those of PSI. This was associated with a lower extent of phosphorylation of PSII core proteins (D1 and CP43). PSII RCs do not totally recover from stress in vte1 even after the nocturnal phase. As a clear compensation for the impeded performance of PSII in the vte1 we noted an increased quantum efficiency of PSI. A pronounced changes between WT and the vte1 mutant were also related to conformation of LHCII at the beginning of photoperiod, suggesting the absence of LHCII trimers in the mutant. The thylakoids thickness was similar in WT and vte1 under LL, but a pronounced unstacking of thylakoids was evoked by HL only in vte1. In conclusion, we postulate that action of 1O2 on PSII in vte1 leads to some permanent damage at PSII core and at LHCII already under LL.
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Affiliation(s)
- Ewa Niewiadomska
- The F. Górski Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239 Kraków, Poland
| | - Kathleen Brückner
- Leibniz Institute of Plant Biochemistry, Department of Cell and Metabolic Biology, Weinberg 3, 06120 Halle, Germany.
| | - Maria Mulisch
- Institute of Botany, Christian-Albrechts-University of Kiel, Olshausenstr, 40, 24098 Kiel, Germany.
| | - Jerzy Kruk
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland.
| | - Aleksandra Orzechowska
- Department of Medical Physics and Biophysics, Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Reymonta 19, 30-059 Krakow, Poland.
| | - Maria Pilarska
- The F. Górski Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239 Kraków, Poland.
| | - Rafał Luchowski
- Department of Biophysics, Institute of Physics, Maria Curie-Sklodowska University, 20-031 Lublin, Poland.
| | - Wiesław I Gruszecki
- Department of Biophysics, Institute of Physics, Maria Curie-Sklodowska University, 20-031 Lublin, Poland.
| | - Karin Krupinska
- Institute of Botany, Christian-Albrechts-University of Kiel, Olshausenstr, 40, 24098 Kiel, Germany.
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26
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Lipid polymorphism in chloroplast thylakoid membranes - as revealed by 31P-NMR and time-resolved merocyanine fluorescence spectroscopy. Sci Rep 2017; 7:13343. [PMID: 29042649 PMCID: PMC5645462 DOI: 10.1038/s41598-017-13574-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 09/25/2017] [Indexed: 01/22/2023] Open
Abstract
Chloroplast thylakoid membranes contain virtually all components of the energy-converting photosynthetic machinery. Their energized state, driving ATP synthesis, is enabled by the bilayer organization of the membrane. However, their most abundant lipid species is a non-bilayer-forming lipid, monogalactosyl-diacylglycerol; the role of lipid polymorphism in these membranes is poorly understood. Earlier 31P-NMR experiments revealed the coexistence of a bilayer and a non-bilayer, isotropic lipid phase in spinach thylakoids. Packing of lipid molecules, tested by fluorescence spectroscopy of the lipophilic dye, merocyanine-540 (MC540), also displayed heterogeneity. Now, our 31P-NMR experiments on spinach thylakoids uncover the presence of a bilayer and three non-bilayer lipid phases; time-resolved fluorescence spectroscopy of MC540 also reveals the presence of multiple lipidic environments. It is also shown by 31P-NMR that: (i) some lipid phases are sensitive to the osmolarity and ionic strength of the medium, (ii) a lipid phase can be modulated by catalytic hydrogenation of fatty acids and (iii) a marked increase of one of the non-bilayer phases upon lowering the pH of the medium is observed. These data provide additional experimental evidence for the polymorphism of lipid phases in thylakoids and suggest that non-bilayer phases play an active role in the structural dynamics of thylakoid membranes.
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27
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Bar Eyal L, Ranjbar Choubeh R, Cohen E, Eisenberg I, Tamburu C, Dorogi M, Ünnep R, Appavou MS, Nevo R, Raviv U, Reich Z, Garab G, van Amerongen H, Paltiel Y, Keren N. Changes in aggregation states of light-harvesting complexes as a mechanism for modulating energy transfer in desert crust cyanobacteria. Proc Natl Acad Sci U S A 2017; 114:9481-9486. [PMID: 28808031 PMCID: PMC5584450 DOI: 10.1073/pnas.1708206114] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In this paper we propose an energy dissipation mechanism that is completely reliant on changes in the aggregation state of the phycobilisome light-harvesting antenna components. All photosynthetic organisms regulate the efficiency of excitation energy transfer (EET) to fit light energy supply to biochemical demands. Not many do this to the extent required of desert crust cyanobacteria. Following predawn dew deposition, they harvest light energy with maximum efficiency until desiccating in the early morning hours. In the desiccated state, absorbed energy is completely quenched. Time and spectrally resolved fluorescence emission measurements of the desiccated desert crust Leptolyngbya ohadii strain identified (i) reduced EET between phycobilisome components, (ii) shorter fluorescence lifetimes, and (iii) red shift in the emission spectra, compared with the hydrated state. These changes coincide with a loss of the ordered phycobilisome structure, evident from small-angle neutron and X-ray scattering and cryo-transmission electron microscopy data. Based on these observations we propose a model where in the hydrated state the organized rod structure of the phycobilisome supports directional EET to reaction centers with minimal losses due to thermal dissipation. In the desiccated state this structure is lost, giving way to more random aggregates. The resulting EET path will exhibit increased coupling to the environment and enhanced quenching.
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Affiliation(s)
- Leeat Bar Eyal
- Department of Plant & Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Reza Ranjbar Choubeh
- Laboratory of Biophysics, Wageningen University, 6700 ET Wageningen, The Netherlands
| | - Eyal Cohen
- Applied Physics Department, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Ido Eisenberg
- Applied Physics Department, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Carmen Tamburu
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Márta Dorogi
- Biological Research Centre, Hungarian Academy of Sciences, Szeged 6726, Hungary
| | - Renata Ünnep
- Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1525 Budapest 114, Hungary
| | - Marie-Sousai Appavou
- Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, Forschungszentrum Jülich GmbH, 85748 Garching, Germany
| | - Reinat Nevo
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7600, Israel
| | - Uri Raviv
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Ziv Reich
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7600, Israel
| | - Győző Garab
- Biological Research Centre, Hungarian Academy of Sciences, Szeged 6726, Hungary
| | - Herbert van Amerongen
- Laboratory of Biophysics, Wageningen University, 6700 ET Wageningen, The Netherlands
| | - Yossi Paltiel
- Applied Physics Department, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Nir Keren
- Department of Plant & Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel;
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28
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Ünnep R, Zsiros O, Hörcsik Z, Markó M, Jajoo A, Kohlbrecher J, Garab G, Nagy G. Low-pH induced reversible reorganizations of chloroplast thylakoid membranes - As revealed by small-angle neutron scattering. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2017; 1858:360-365. [PMID: 28237493 DOI: 10.1016/j.bbabio.2017.02.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 02/13/2017] [Accepted: 02/15/2017] [Indexed: 12/20/2022]
Abstract
Energization of thylakoid membranes brings about the acidification of the lumenal aqueous phase, which activates important regulatory mechanisms. Earlier Jajoo and coworkers (2014 FEBS Lett. 588:970) have shown that low pH in isolated plant thylakoid membranes induces changes in the excitation energy distribution between the two photosystems. In order to elucidate the structural background of these changes, we used small-angle neutron scattering on thylakoid membranes exposed to low p2H (pD) and show that gradually lowering the p2H from 8.0 to 5.0 causes small but well discernible reversible diminishment of the periodic order and the lamellar repeat distance and an increased mosaicity - similar to the effects elicited by light-induced acidification of the lumen. Our data strongly suggest that thylakoids dynamically respond to the membrane energization and actively participate in different regulatory mechanisms.
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Affiliation(s)
- Renáta Ünnep
- Wigner Research Centre for Physics, Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, H-1121 Budapest, Hungary; Paul Scherrer Institute, Laboratory for Neutron Scattering and Imaging, 5232 Villigen PSI, Switzerland
| | - Ottó Zsiros
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, POB 521, H-6701 Szeged, Hungary
| | - Zsolt Hörcsik
- College of Nyíregyháza, Institute of Environmental Science, H-4400 Nyíregyháza, Hungary
| | - Márton Markó
- Wigner Research Centre for Physics, Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, H-1121 Budapest, Hungary
| | - Anjana Jajoo
- School of Life Science, Devi Ahilya University, Khandwa Road, Indore 452 001, India
| | - Joachim Kohlbrecher
- Paul Scherrer Institute, Laboratory for Neutron Scattering and Imaging, 5232 Villigen PSI, Switzerland
| | - Győző Garab
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, POB 521, H-6701 Szeged, Hungary; Department of Physics, Faculty of Science, Ostrava University, Chittussiho 10, CZ-710 0 Ostrava - Slezská Ostrava, Czech Republic.
| | - Gergely Nagy
- Paul Scherrer Institute, Laboratory for Neutron Scattering and Imaging, 5232 Villigen PSI, Switzerland; Wigner Research Centre for Physics, Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, H-1121 Budapest, Hungary.
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29
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Tong Z, Yang D, Li Z, Nan Y, Ding F, Shen Y, Jiang Z. Thylakoid-Inspired Multishell g-C 3N 4 Nanocapsules with Enhanced Visible-Light Harvesting and Electron Transfer Properties for High-Efficiency Photocatalysis. ACS NANO 2017; 11:1103-1112. [PMID: 28032986 DOI: 10.1021/acsnano.6b08251] [Citation(s) in RCA: 169] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Inspired by the orderly stacked nanostructure and highly integrated function of thylakoids in a natural photosynthesis system, multishell g-C3N4 (MSCN) nanocapsule photocatalysts have been prepared by SiO2 hard template with different shell layers. The resultant triple-shell g-C3N4 (TSCN) nanocapsules display superior photocatalysis performance to single-shell and double-shell counterparts owing to excellent visible-light harvesting and electron transfer properties. Specially, with the increase of the shell layer number, light harvesting is greatly enhanced. There is an increase of the entire visible range absorption arising from the multiple scattering and reflection of the incident light within multishell nanoarchitectures as well as the light transmission within the porous thin shells, and an increase of absorption edge arising from the decreased quantum size effect. The electron transfer is greatly accelerated by the mesopores in the thin shells as nanoconduits and the high specific surface area of TSCN (310.7 m2 g-1). With the tailored hierarchical nanostructure features, TSCN exhibits a superior visible-light H2-generation activity of 630 μmol h-1 g-1 (λ > 420 nm), which is among one of the most efficient metal-free g-C3N4 photocatalysts. This study demonstrates a bioinspired approach to the rational design of high-performance nanostructured visible-light photocatalysts.
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Affiliation(s)
- Zhenwei Tong
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Tianjin 300072, China
| | | | - Zhen Li
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Tianjin 300072, China
| | - Yanhu Nan
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Tianjin 300072, China
| | - Fei Ding
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Tianjin 300072, China
| | - Yichun Shen
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Tianjin 300072, China
| | - Zhongyi Jiang
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Tianjin 300072, China
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30
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Lindquist E, Solymosi K, Aronsson H. Vesicles Are Persistent Features of Different Plastids. Traffic 2016; 17:1125-38. [PMID: 27405297 DOI: 10.1111/tra.12427] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 07/08/2016] [Accepted: 07/08/2016] [Indexed: 02/06/2023]
Abstract
Peripheral vesicles in plastids have been observed repeatedly, primarily in proplastids and developing chloroplasts, in which they are suggested to function in thylakoid biogenesis. Previous observations of vesicles in mature chloroplasts have mainly concerned low temperature pretreated plants occasionally treated with inhibitors blocking vesicle fusion. Here, we show that such vesicle-like structures occur not only in chloroplasts and proplastids, but also in etioplasts, etio-chloroplasts, leucoplasts, chromoplasts and even transforming desiccoplasts without any specific pretreatment. Observations are made both in C3 and C4 species, in different cell types (meristematic, epidermis, mesophyll, bundle sheath and secretory cells) and different organs (roots, stems, leaves, floral parts and fruits). Until recently not much focus has been given to the idea that vesicle transport in chloroplasts could be mediated by proteins, but recent data suggest that the vesicle system of chloroplasts has similarities with the cytosolic coat protein complex II system. All current data taken together support the idea of an ongoing, active and protein-mediated vesicle transport not only in chloroplasts but also in other plastids, obviously occurring regardless of chemical modifications, temperature and plastid developmental stage.
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Affiliation(s)
- Emelie Lindquist
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, SE-405 30, Gothenburg, Sweden
| | - Katalin Solymosi
- Department of Plant Anatomy, Institute of Biology, Eötvös Loránd University, Pázmány P. s. 1/c, H-1117, Budapest, Hungary
| | - Henrik Aronsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, SE-405 30, Gothenburg, Sweden.
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31
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Yoshioka-Nishimura M. Close Relationships Between the PSII Repair Cycle and Thylakoid Membrane Dynamics. PLANT & CELL PHYSIOLOGY 2016; 57:1115-22. [PMID: 27017619 DOI: 10.1093/pcp/pcw050] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 02/26/2016] [Indexed: 05/10/2023]
Abstract
In chloroplasts, a three-dimensional network of thylakoid membranes is formed by stacked grana and interconnecting stroma thylakoids. The grana are crowded with photosynthetic proteins, where PSII-light harvesting complex II (LHCII) supercomplexes often show semi-crystalline arrays for efficient energy trapping, transfer and use. Although light is essential for photosynthesis, PSII is damaged by reactive oxygen species that are generated from primary photochemical reactions when plants are exposed to excess light. Because PSII complexes are embedded in the lipid bilayers of thylakoid membranes, their functions are affected by the conditions of the lipids. Electron paramagnetic resonance (EPR) spin trapping measurements showed that singlet oxygen was formed through peroxidation of thylakoid lipids, suggesting that lipid peroxidation can damage proteins, including the D1 protein. After photodamage, PSII is restored by a specific repair system in thylakoid membranes. In the PSII repair cycle, phosphorylation and dephosphorylation of the PSII proteins control the timing of PSII disassembly and subsequent degradation of the D1 protein. Under light stress, stacked grana turn into unstacked thylakoids with bent grana margins. These structural changes may be closely linked to the mechanisms of the PSII repair cycle because PSII can move more easily from the grana core to the stroma thylakoids through an expanded stromal gap between each thylakoid. Thus, plants modulate the structure of thylakoid membranes under high light to carry out efficient PSII repair. This review focuses on the behavior of the PSII complex and the active role of structural changes to thylakoid membranes under light stress.
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Affiliation(s)
- Miho Yoshioka-Nishimura
- Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530 Japan
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32
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Herdean A, Teardo E, Nilsson AK, Pfeil BE, Johansson ON, Ünnep R, Nagy G, Zsiros O, Dana S, Solymosi K, Garab G, Szabó I, Spetea C, Lundin B. A voltage-dependent chloride channel fine-tunes photosynthesis in plants. Nat Commun 2016; 7:11654. [PMID: 27216227 PMCID: PMC4890181 DOI: 10.1038/ncomms11654] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 04/16/2016] [Indexed: 11/17/2022] Open
Abstract
In natural habitats, plants frequently experience rapid changes in the intensity of sunlight. To cope with these changes and maximize growth, plants adjust photosynthetic light utilization in electron transport and photoprotective mechanisms. This involves a proton motive force (PMF) across the thylakoid membrane, postulated to be affected by unknown anion (Cl(-)) channels. Here we report that a bestrophin-like protein from Arabidopsis thaliana functions as a voltage-dependent Cl(-) channel in electrophysiological experiments. AtVCCN1 localizes to the thylakoid membrane, and fine-tunes PMF by anion influx into the lumen during illumination, adjusting electron transport and the photoprotective mechanisms. The activity of AtVCCN1 accelerates the activation of photoprotective mechanisms on sudden shifts to high light. Our results reveal that AtVCCN1, a member of a conserved anion channel family, acts as an early component in the rapid adjustment of photosynthesis in variable light environments.
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Affiliation(s)
- Andrei Herdean
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Enrico Teardo
- Department of Biology, University of Padova, Padova 35121, Italy
| | - Anders K. Nilsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Bernard E. Pfeil
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Oskar N. Johansson
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Renáta Ünnep
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen 5232, Switzerland
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest 1121, Hungary
| | - Gergely Nagy
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen 5232, Switzerland
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest 1121, Hungary
| | - Ottó Zsiros
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Szeged 6701, Hungary
| | - Somnath Dana
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Katalin Solymosi
- Department of Plant Anatomy, Eötvös Loránd University, Budapest 1117, Hungary
| | - Győző Garab
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Szeged 6701, Hungary
| | - Ildikó Szabó
- Department of Biology, University of Padova, Padova 35121, Italy
- CNR Neuroscience Institute, Padova 35121, Italy
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Björn Lundin
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg 40530, Sweden
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33
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Fingerprinting the macro-organisation of pigment-protein complexes in plant thylakoid membranes in vivo by circular-dichroism spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1479-1489. [PMID: 27154055 DOI: 10.1016/j.bbabio.2016.04.287] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 04/30/2016] [Indexed: 11/24/2022]
Abstract
Macro-organisation of the protein complexes in plant thylakoid membranes plays important roles in the regulation and fine-tuning of photosynthetic activity. These delicate structures might, however, undergo substantial changes during isolating the thylakoid membranes or during sample preparations, e.g., for electron microscopy. Circular-dichroism (CD) spectroscopy is a non-invasive technique which can thus be used on intact samples. Via excitonic and psi-type CD bands, respectively, it carries information on short-range excitonic pigment-pigment interactions and the macro-organisation (chiral macrodomains) of pigment-protein complexes (psi, polymer or salt-induced). In order to obtain more specific information on the origin of the major psi-type CD bands, at around (+)506, (-)674 and (+)690nm, we fingerprinted detached leaves and isolated thylakoid membranes of wild-type and mutant plants and also tested the effects of different environmental conditions in vivo. We show that (i) the chiral macrodomains disassemble upon mild detergent treatments, but not after crosslinking the protein complexes; (ii) in different wild-type leaves of dicotyledonous and monocotyledonous angiosperms the CD features are quite robust, displaying very similar excitonic and psi-type bands, suggesting similar protein composition and (macro-) organisation of photosystem II (PSII) supercomplexes in the grana; (iii) the main positive psi-type bands depend on light-harvesting protein II contents of the membranes; (iv) the (+)506nm band appears only in the presence of PSII-LHCII supercomplexes and does not depend on the xanthophyll composition of the membranes. Hence, CD spectroscopy can be used to detect different macro-domains in the thylakoid membranes with different outer antenna compositions in vivo.
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34
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Garab G. Self-assembly and structural-functional flexibility of oxygenic photosynthetic machineries: personal perspectives. PHOTOSYNTHESIS RESEARCH 2016; 127:131-50. [PMID: 26494196 DOI: 10.1007/s11120-015-0192-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 09/02/2015] [Indexed: 05/24/2023]
Abstract
This short review, with a bit of historical aspect and a strong personal bias and emphases on open questions, is focusing on the (macro-)organization and structural-functional flexibilities of the photosynthetic apparatus of oxygenic photosynthetic organisms at different levels of the structural complexity-selected problems that have attracted most my attention in the past years and decades. These include (i) the anisotropic organization of the pigment-protein complexes and photosynthetic membranes-a basic organizing principle of living matter, which can, and probably should be adopted to intelligent materials; (ii) the organization of protein complexes into chiral macrodomains, large self-assembling highly organized but structurally flexible entities with unique spectroscopic fingerprints-structures, where, important, high-level regulatory functions appear to 'reside'; (iii) a novel, dissipation-assisted mechanism of structural changes, based on a thermo-optic effect: ultrafast thermal transients in the close vicinity of dissipation of unused excitation energy, which is capable of inducing elementary structural changes; it makes plants capable of responding to excess excitation with reaction rates proportional to the overexcitation above the light-saturation of photosynthesis; (iv) the 3D ultrastructure of the granum-stroma thylakoid membrane assembly and other multilamellar membrane systems, and their remodelings-associated with regulatory mechanisms; (v) the molecular organization and structural-functional plasticity of the main light-harvesting complex of plants, in relation to their crystal structure and different in vivo and in vitro states; and (vi) the enigmatic role of non-bilayer lipids and lipid phases in the bilayer thylakoid membrane-warranting its high protein content and contributing to its structural flexibility.
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35
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Karlsson PM, Herdean A, Adolfsson L, Beebo A, Nziengui H, Irigoyen S, Ünnep R, Zsiros O, Nagy G, Garab G, Aronsson H, Versaw WK, Spetea C. The Arabidopsis thylakoid transporter PHT4;1 influences phosphate availability for ATP synthesis and plant growth. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 84:99-110. [PMID: 26255788 DOI: 10.1111/tpj.12962] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 07/14/2015] [Accepted: 08/03/2015] [Indexed: 05/24/2023]
Abstract
The Arabidopsis phosphate transporter PHT4;1 was previously localized to the chloroplast thylakoid membrane. Here we investigated the physiological consequences of the absence of PHT4;1 for photosynthesis and plant growth. In standard growth conditions, two independent Arabidopsis knockout mutant lines displayed significantly reduced leaf size and biomass but normal phosphorus content. When mutants were grown in high-phosphate conditions, the leaf phosphorus levels increased and the growth phenotype was suppressed. Photosynthetic measurements indicated that in the absence of PHT4;1 stromal phosphate was reduced to levels that limited ATP synthase activity. This resulted in reduced CO2 fixation and accumulation of soluble sugars, limiting plant growth. The mutants also displayed faster induction of non-photochemical quenching than the wild type, in line with the increased contribution of ΔpH to the proton-motive force across thylakoids. Small-angle neutron scattering showed a smaller lamellar repeat distance, whereas circular dichroism spectroscopy indicated a perturbed long-range order of photosystem II (PSII) complexes in the mutant thylakoids. The absence of PHT4;1 did not alter the PSII repair cycle, as indicated by wild-type levels of phosphorylation of PSII proteins, inactivation and D1 protein degradation. Interestingly, the expression of genes for several thylakoid proteins was downregulated in the mutants, but the relative levels of the corresponding proteins were either not affected or could not be discerned. Based on these data, we propose that PHT4;1 plays an important role in chloroplast phosphate compartmentation and ATP synthesis, which affect plant growth. It also maintains the ionic environment of thylakoids, which affects the macro-organization of complexes and induction of photoprotective mechanisms.
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Affiliation(s)
- Patrik M Karlsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, Gothenburg, 405 30, Sweden
| | - Andrei Herdean
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, Gothenburg, 405 30, Sweden
| | - Lisa Adolfsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, Gothenburg, 405 30, Sweden
| | - Azeez Beebo
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, Gothenburg, 405 30, Sweden
| | - Hugues Nziengui
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, Gothenburg, 405 30, Sweden
| | - Sonia Irigoyen
- Department of Biology, Texas A&M University, 3258, TAMU College Station, TX, 77843, USA
| | - Renáta Ünnep
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen PSI, 5232, Switzerland
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Box 49, Budapest, H-1525, Hungary
| | - Ottó Zsiros
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Box 521, Szeged, H-6701, Hungary
| | - Gergely Nagy
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen PSI, 5232, Switzerland
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Box 49, Budapest, H-1525, Hungary
| | - Győző Garab
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Box 521, Szeged, H-6701, Hungary
| | - Henrik Aronsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, Gothenburg, 405 30, Sweden
| | - Wayne K Versaw
- Department of Biology, Texas A&M University, 3258, TAMU College Station, TX, 77843, USA
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, Gothenburg, 405 30, Sweden
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Stoichev S, Krumova SB, Andreeva T, Busto JV, Todinova S, Balashev K, Busheva M, Goñi FM, Taneva SG. Low pH modulates the macroorganization and thermal stability of PSII supercomplexes in grana membranes. Biophys J 2015; 108:844-853. [PMID: 25692589 PMCID: PMC4336371 DOI: 10.1016/j.bpj.2014.12.042] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 12/08/2014] [Accepted: 12/22/2014] [Indexed: 11/25/2022] Open
Abstract
Protonation of the lumen-exposed residues of some photosynthetic complexes in the grana membranes occurs under conditions of high light intensity and triggers a major photoprotection mechanism known as energy dependent nonphotochemical quenching. We have studied the role of protonation in the structural reorganization and thermal stability of isolated grana membranes. The macroorganization of granal membrane fragments in protonated and partly deprotonated state has been mapped by means of atomic force microscopy. The protonation of the photosynthetic complexes has been found to induce large-scale structural remodeling of grana membranes-formation of extensive domains of the major light-harvesting complex of photosystem II and clustering of trimmed photosystem II supercomplexes, thinning of the membrane, and reduction of its size. These events are accompanied by pronounced thermal destabilization of the photosynthetic complexes, as evidenced by circular dichroism spectroscopy and differential scanning calorimetry. Our data reveal a detailed nanoscopic picture of the initial steps of nonphotochemical quenching.
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Affiliation(s)
- Svetozar Stoichev
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Sashka B Krumova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Tonya Andreeva
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Jon V Busto
- Unidad de Biofísica (CSIC, UPV-EHU) and Departamento de Bioquímica, Universidad del País Vasco, Leioa, Spain
| | - Svetla Todinova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Konstantin Balashev
- Department of Physical Chemistry, Faculty of Chemistry and Pharmacy, Sofia University "St. Kliment Ohridski," Sofia, Bulgaria
| | - Mira Busheva
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Félix M Goñi
- Unidad de Biofísica (CSIC, UPV-EHU) and Departamento de Bioquímica, Universidad del País Vasco, Leioa, Spain
| | - Stefka G Taneva
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria; Unidad de Biofísica (CSIC, UPV-EHU) and Departamento de Bioquímica, Universidad del País Vasco, Leioa, Spain.
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37
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Unnep R, Nagy G, Markó M, Garab G. Monitoring thylakoid ultrastructural changes in vivo using small-angle neutron scattering. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 81:197-207. [PMID: 24629664 DOI: 10.1016/j.plaphy.2014.02.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 02/08/2014] [Indexed: 05/01/2023]
Abstract
The light reactions of oxygenic photosynthesis take place in the thylakoid membranes, flattened vesicles, which contain the two photosystems and also embed the cytochrome b6f complex and the ATP synthase. In general, the thylakoid membranes are assembled into multilamellar membrane systems, which warrant an optimal light capturing efficiency. In nature, they show astounding variations, primarily due to large variations in their protein composition, which is controlled by multilevel regulatory mechanisms during long-term acclimation and short-term adaptation processes and also influenced by biotic or abiotic stresses - indicating a substantial degree of flexibility in the membrane ultrastructure. The better understanding of the dynamic features of this membrane system requires the use of non-invasive techniques, such as small angle neutron scattering (SANS), which is capable of providing accurate, statistically and spatially averaged information on the repeat distances of periodically organized thylakoid membranes under physiologically relevant conditions with time resolutions of seconds and minutes. In this review, after a short section on the basic properties of neutrons, we outline the fundamental principles of SANS measurements, its strengths and weaknesses in comparison to complementary structure investigation techniques. Then we overview recent results on isolated plant thylakoid membranes, and on living cyanobacterial and algal cells as well as on whole leaves. Special attention is paid to light-induced reversible ultrastructural changes in vivo, which, in cyanobacterial and diatom cells, were uncovered with the aid of SANS measurements; we also discuss the role of membrane reorganizations in light adaptation and photoprotection mechanisms.
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Affiliation(s)
- Renáta Unnep
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, POB 49, H-1525 Budapest, Hungary
| | - Gergely Nagy
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, POB 49, H-1525 Budapest, Hungary; Laboratory for Neutron Scattering, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Márton Markó
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, POB 49, H-1525 Budapest, Hungary; Laboratory for Neutron Scattering, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Győző Garab
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, POB 521, H-6701 Szeged, Hungary.
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