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Wilson S, Li DH, Ruban AV. The Structural and Spectral Features of Light-Harvesting Complex II Proteoliposomes Mimic Those of Native Thylakoid Membranes. J Phys Chem Lett 2022; 13:5683-5691. [PMID: 35709359 PMCID: PMC9237827 DOI: 10.1021/acs.jpclett.2c01019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
The major photosystem II light-harvesting antenna (LHCII) is the most abundant membrane protein in nature and plays an indispensable role in light harvesting and photoprotection in the plant thylakoid. Here, we show that "pseudothylakoid characteristics" can be observed in artificial LHCII membranes. In our proteoliposomal system, at high LHCII densities, the liposomes become stacked, mimicking the in vivo thylakoid grana membranes. Furthermore, an unexpected, unstructured emission peak at ∼730 nm appears, similar in appearance to photosystem I emission, but with a clear excimeric character that has never been previously reported. These states correlate with the increasing density of LHCII in the membrane and a decrease in its average fluorescence lifetime. The appearance of these low-energy states can also occur in natural plant membrane structures, which has unique consequences for the interpretation of the spectroscopic and physiological properties of the photosynthetic membrane.
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Combined dynamics of the 500-600 nm leaf absorption and chlorophyll fluorescence changes in vivo: Evidence for the multifunctional energy quenching role of xanthophylls. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148351. [PMID: 33285101 DOI: 10.1016/j.bbabio.2020.148351] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/23/2020] [Accepted: 11/30/2020] [Indexed: 11/21/2022]
Abstract
Carotenoids (Cars) regulate the energy flow towards the reaction centres in a versatile way whereby the switch between energy harvesting and dissipation is strongly modulated by the operation of the xanthophyll cycles. However, the cascade of molecular mechanisms during the change from light harvesting to energy dissipation remains spectrally poorly understood. By characterizing the in vivo absorbance changes (ΔA) of leaves from four species in the 500-600 nm range through a Gaussian decomposition, while measuring passively simultaneous Chla fluorescence (F) changes, we present a direct observation of the quick antenna adjustments during a 3-min dark-to-high-light induction. Underlying spectral behaviours of the 500-600 nm ΔA feature can be characterized by a minimum set of three Gaussians distinguishing very quick dynamics during the first minute. Our results show the parallel trend of two Gaussian components and the prompt Chla F quenching. Further, we observe similar quick kinetics between the relative behaviour of these components and the in vivo formations of antheraxanthin (Ant) and zeaxanthin (Zea), in parallel with the dynamic quenching of singlet excited chlorophyll a (1Chla*) states. After these simultaneous quick kinetical behaviours of ΔA and F during the first minute, the 500-600 nm feature continues to increase, indicating a further enhanced absorption driven by the centrally located Gaussian until 3 min after sudden light exposure. Observing these precise underlying kinetic trends of the spectral behaviour in the 500-600 nm region shows the large potential of in vivo leaf spectroscopy to bring new insights on the quick redistribution and relaxation of excitation energy, indicating a key role for both Ant and Zea.
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Stirbet A, Lazár D, Guo Y, Govindjee G. Photosynthesis: basics, history and modelling. ANNALS OF BOTANY 2020; 126:511-537. [PMID: 31641747 PMCID: PMC7489092 DOI: 10.1093/aob/mcz171] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/06/2019] [Accepted: 10/21/2019] [Indexed: 05/02/2023]
Abstract
BACKGROUND With limited agricultural land and increasing human population, it is essential to enhance overall photosynthesis and thus productivity. Oxygenic photosynthesis begins with light absorption, followed by excitation energy transfer to the reaction centres, primary photochemistry, electron and proton transport, NADPH and ATP synthesis, and then CO2 fixation (Calvin-Benson cycle, as well as Hatch-Slack cycle). Here we cover some of the discoveries related to this process, such as the existence of two light reactions and two photosystems connected by an electron transport 'chain' (the Z-scheme), chemiosmotic hypothesis for ATP synthesis, water oxidation clock for oxygen evolution, steps for carbon fixation, and finally the diverse mechanisms of regulatory processes, such as 'state transitions' and 'non-photochemical quenching' of the excited state of chlorophyll a. SCOPE In this review, we emphasize that mathematical modelling is a highly valuable tool in understanding and making predictions regarding photosynthesis. Different mathematical models have been used to examine current theories on diverse photosynthetic processes; these have been validated through simulation(s) of available experimental data, such as chlorophyll a fluorescence induction, measured with fluorometers using continuous (or modulated) exciting light, and absorbance changes at 820 nm (ΔA820) related to redox changes in P700, the reaction centre of photosystem I. CONCLUSIONS We highlight here the important role of modelling in deciphering and untangling complex photosynthesis processes taking place simultaneously, as well as in predicting possible ways to obtain higher biomass and productivity in plants, algae and cyanobacteria.
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Affiliation(s)
| | - Dušan Lazár
- Department of Biophysics, Center of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Ya Guo
- Key Laboratory of Advanced Process Control for Light Industry (Ministry of Education), Jiangnan University, Wuxi, China
- University of Missouri, Columbia, MO, USA
| | - Govindjee Govindjee
- Department of Biochemistry, Department of Plant Biology, and Center of Biophysics & Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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Silva FB, Costa AC, Müller C, Nascimento KT, Batista PF, Vital RG, Megguer CA, Jakelaitis A, Domingos M. Dipteryx alata, a tree native to the Brazilian Cerrado, is sensitive to the herbicide nicosulfuron. ECOTOXICOLOGY (LONDON, ENGLAND) 2020; 29:217-225. [PMID: 32030573 DOI: 10.1007/s10646-019-02154-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/13/2019] [Indexed: 06/10/2023]
Abstract
The expansion of land use for agricultural interests and the excessive use of herbicides are among the causes of biodiversity losses in the Brazilian Cerrado biome. Therefore, we aimed to test the hypothesis that Dipteryx alata Vogel, a common species in this biome, is sensitive to nicosulfuron because of its high phytotoxicity. We evaluated physiological, biochemical and morphological responses in D. alata plants exposed to increasing doses of the herbicide. Young plants were transplanted to 10 L pots containing substrate composed of soil and sand (2:1) after fertilization. After an acclimation period, the following doses of nicosulfuron were applied: 0 (control), 6, 12, 24, 48, and 60 g a.e. ha-1. The experiment was conducted in a randomized block design factorial scheme with six doses of nicosulfuron, three evaluation times, and five replicates per treatment. The effects of the herbicide were assessed by measuring gas exchange, chlorophyll a fluorescence, photosynthetic pigments, membrane permeability, antioxidant enzymes and acetolactate synthase. Nicosulfuron altered the photosynthetic machinery and enzymatic metabolism of D. alata. Reductions in physiological traits, increased catalase and ascorbate peroxidase activities, enhanced malondialdehyde concentrations rate of electrolyte leakage and decreased acetolactate synthase activity in response to nicosulfuron all suggest that D. alata is sensitive to this herbicide.
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Affiliation(s)
- Fábia Barbosa Silva
- Instituto Federal de Educação, Ciência e Tecnologia Goiano-Campus Rio Verde, Caixa Postal 66, Rio Verde, GO, 75901-9 70, Brazil
- Laboratório de Estudo de Plantas sob Estresse, Universidade de Sao Paulo, Escola Superior de Agricultura "Luiz de Queiroz", Caixa Postal 9, Piracicaba, SP, 13418-900, Brazil
| | - Alan Carlos Costa
- Instituto Federal de Educação, Ciência e Tecnologia Goiano-Campus Rio Verde, Caixa Postal 66, Rio Verde, GO, 75901-9 70, Brazil.
| | - Caroline Müller
- Instituto Federal de Educação, Ciência e Tecnologia Goiano-Campus Rio Verde, Caixa Postal 66, Rio Verde, GO, 75901-9 70, Brazil
| | - Kelly Telles Nascimento
- Instituto Federal de Educação, Ciência e Tecnologia Goiano-Campus Rio Verde, Caixa Postal 66, Rio Verde, GO, 75901-9 70, Brazil
| | - Priscila Ferreira Batista
- Instituto Federal de Educação, Ciência e Tecnologia Goiano-Campus Rio Verde, Caixa Postal 66, Rio Verde, GO, 75901-9 70, Brazil
| | - Roberto Gomes Vital
- Instituto Federal de Educação, Ciência e Tecnologia Goiano-Campus Rio Verde, Caixa Postal 66, Rio Verde, GO, 75901-9 70, Brazil
| | - Clarice Aparecida Megguer
- Instituto Federal de Educação, Ciência e Tecnologia Goiano-Campus Morrinhos, Caixa Postal 92, Morrinhos, GO, 75650-000, Brazil
| | - Adriano Jakelaitis
- Instituto Federal de Educação, Ciência e Tecnologia Goiano-Campus Rio Verde, Caixa Postal 66, Rio Verde, GO, 75901-9 70, Brazil
| | - Marisa Domingos
- Instituto de Botânica, Núcleo de Pesquisa em Ecologia, Caixa Postal 68041, São Paulo, SP, 04045-972, Brazil
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Hutfilz A, Sonntag SR, Lewke B, Theisen-Kunde D, Grisanti S, Brinkmann R, Miura Y. Fluorescence Lifetime Imaging Ophthalmoscopy of the Retinal Pigment Epithelium During Wound Healing After Laser Irradiation. Transl Vis Sci Technol 2019; 8:12. [PMID: 31588376 PMCID: PMC6748347 DOI: 10.1167/tvst.8.5.12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 06/19/2019] [Indexed: 12/22/2022] Open
Abstract
Purpose To investigate the change in fluorescence lifetime of retinal pigment epithelium (RPE) after laser irradiation by using an organ culture model. Methods Porcine RPE-choroid-sclera explants were irradiated with selective retina treatment laser (wavelength: 527 nm, beam diameter: 200 μm, energy: 80–150 μJ). At 24 and 72 hours after irradiation, the mean fluorescence lifetime (τm) was measured with fluorescence lifetime imaging ophthalmoscopy (FLIO) (excitation wavelength: 473 nm, emission: short spectral channel: 498-560 nm, long spectral channel: 560–720 nm). For every laser spot, central damaged zone (zone 1: 120 × 120 μm), area including wound rim (280 × 280 μm except zone 1), and environmental zone (440 × 440 μm except zone 1 and 2) were analyzed. Peripheral zone at a distance from laser spots longer than 2000 μm was examined for comparison. Cell viability was evaluated with calcein-acetoxymethyl ester and morphology with fluorescence microscopy for filamentous-actin. Results The RPE defect after selective retina treatment was mostly closed within 72 hours. FLIO clearly demarcated the irradiated region, with prolonged τm at the center of the defect decreasing with eccentricity. In short spectral channel, but not in long spectral channel, τm in the environmental zone after 72 hours was still significantly longer than in the peripheral zone. Conclusions FLIO may clearly demarcate the RPE defect, demonstrate its closure, and, moreover, indicate the induced metabolic changes of surrounding cells during wound healing. Translational Relevance This ex vivo study showed that FLIO may be used to evaluate the extent and quality of restoration of the damaged RPE and to detect its metabolic change in human fundus noninvasively.
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Affiliation(s)
- Alessa Hutfilz
- Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany.,Medical Laser Center Lübeck, Lübeck, Germany
| | - Svenja Rebecca Sonntag
- Department of Ophthalmology, University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Britta Lewke
- Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany.,Medical Laser Center Lübeck, Lübeck, Germany
| | | | - Salvatore Grisanti
- Department of Ophthalmology, University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Ralf Brinkmann
- Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany.,Medical Laser Center Lübeck, Lübeck, Germany
| | - Yoko Miura
- Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany.,Department of Ophthalmology, University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany.,Medical Laser Center Lübeck, Lübeck, Germany
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Espinoza-Corral R, Heinz S, Klingl A, Jahns P, Lehmann M, Meurer J, Nickelsen J, Soll J, Schwenkert S. Plastoglobular protein 18 is involved in chloroplast function and thylakoid formation. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3981-3993. [PMID: 30976809 PMCID: PMC6685665 DOI: 10.1093/jxb/erz177] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 04/02/2019] [Indexed: 05/05/2023]
Abstract
Plastoglobules are lipoprotein particles that are found in different types of plastids. They contain a very specific and specialized set of lipids and proteins. Plastoglobules are highly dynamic in size and shape, and are therefore thought to participate in adaptation processes during either abiotic or biotic stresses or transitions between developmental stages. They are suggested to function in thylakoid biogenesis, isoprenoid metabolism, and chlorophyll degradation. While several plastoglobular proteins contain identifiable domains, others provide no structural clues to their function. In this study, we investigate the role of plastoglobular protein 18 (PG18), which is conserved from cyanobacteria to higher plants. Analysis of a PG18 loss-of-function mutant in Arabidopsis thaliana demonstrated that PG18 plays an important role in thylakoid formation; the loss of PG18 results in impaired accumulation, assembly, and function of thylakoid membrane complexes. Interestingly, the mutant accumulated less chlorophyll and carotenoids, whereas xanthophyll cycle pigments were increased. Accumulation of photosynthetic complexes is similarly affected in both a Synechocystis and an Arabidopsis PG18 mutant. However, the ultrastructure of cyanobacterial thylakoids is not compromised by the lack of PG18, probably due to its less complex architecture.
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Affiliation(s)
- Roberto Espinoza-Corral
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Planegg-Martinsried, Germany
| | - Steffen Heinz
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Planegg-Martinsried, Germany
| | - Andreas Klingl
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Planegg-Martinsried, Germany
| | - Peter Jahns
- Plant Biochemistry, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Martin Lehmann
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Planegg-Martinsried, Germany
| | - Jörg Meurer
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Planegg-Martinsried, Germany
| | - Jörg Nickelsen
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Planegg-Martinsried, Germany
| | - Jürgen Soll
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Planegg-Martinsried, Germany
- Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Serena Schwenkert
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Planegg-Martinsried, Germany
- Correspondence:
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Pollastri S, Jorba I, Hawkins TJ, Llusià J, Michelozzi M, Navajas D, Peñuelas J, Hussey PJ, Knight MR, Loreto F. Leaves of isoprene-emitting tobacco plants maintain PSII stability at high temperatures. THE NEW PHYTOLOGIST 2019; 223:1307-1318. [PMID: 30980545 DOI: 10.1111/nph.15847] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 04/07/2019] [Indexed: 05/13/2023]
Abstract
At high temperatures, isoprene-emitting plants display a higher photosynthetic rate and a lower nonphotochemical quenching (NPQ) compared with nonemitting plants. The mechanism of this phenomenon, which may be very important under current climate warming, is still elusive. NPQ was dissected into its components, and chlorophyll fluorescence lifetime imaging microscopy (FLIM) was used to analyse the dynamics of excited chlorophyll relaxation in isoprene-emitting and nonemitting plants. Thylakoid membrane stiffness was also measured using atomic force microscope (AFM) to identify a possible mode of action of isoprene in improving photochemical efficiency and photosynthetic stability. We show that, when compared with nonemitters, isoprene-emitting tobacco plants exposed at high temperatures display a reduced increase of the NPQ energy-dependent component (qE) and stable (1) chlorophyll fluorescence lifetime; (2) amplitude of the fluorescence decay components; and (3) thylakoid membrane stiffness. Our study shows for the first time that isoprene maintains PSII stability at high temperatures by preventing the modifications of the surrounding environment, namely providing a more steady and homogeneous distribution of the light-absorbing centres and a stable thylakoid membrane stiffness. Isoprene photoprotects leaves with a mechanism alternative to NPQ, enabling plants to maintain a high photosynthetic rate at rising temperatures.
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Affiliation(s)
- Susanna Pollastri
- Institute for Sustainable Plant Protection, National Research Council of Italy, Via Madonna del Piano 10, Sesto Fiorentino, 50019, Florence, Italy
- Department of Biosciences, Durham University, South Road, DH1 3LE, Durham, UK
| | - Ignasi Jorba
- University of Barcelona and Institute for Bioengineering of Catalonia - The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Timothy J Hawkins
- Department of Biosciences, Durham University, South Road, DH1 3LE, Durham, UK
| | - Joan Llusià
- CSIC, Global Ecology Unit CREAF-CSIC-Universitat Autònoma de Barcelona, Bellaterra, 08193, Catalonia, Spain
- CREAF, Cerdanyola del Vallès, 08193, Catalonia, Spain
| | - Marco Michelozzi
- Institute of Biosciences and Bioresources, National Research Council of Italy, Via Madonna del Piano 10, Sesto Fiorentino, 50019, Florence, Italy
| | - Daniel Navajas
- University of Barcelona and Institute for Bioengineering of Catalonia - The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Josep Peñuelas
- CSIC, Global Ecology Unit CREAF-CSIC-Universitat Autònoma de Barcelona, Bellaterra, 08193, Catalonia, Spain
- CREAF, Cerdanyola del Vallès, 08193, Catalonia, Spain
| | - Patrick J Hussey
- Department of Biosciences, Durham University, South Road, DH1 3LE, Durham, UK
| | - Marc R Knight
- Department of Biosciences, Durham University, South Road, DH1 3LE, Durham, UK
| | - Francesco Loreto
- Department of Biology, Agriculture and Food Sciences, National Research Council of Italy, Piazzale Aldo Moro 7, 00185, Rome, Italy
- Department of Biology, University of Naples Federico II, via Cinthia, 80126, Naples, Italy
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Govindjee. A sixty-year tryst with photosynthesis and related processes: an informal personal perspective. PHOTOSYNTHESIS RESEARCH 2019; 139:15-43. [PMID: 30343396 DOI: 10.1007/s11120-018-0590-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 10/01/2018] [Indexed: 06/08/2023]
Abstract
After briefly describing my early collaborative work at the University of Allahabad, that had laid the foundation of my research life, I present here some of our research on photosynthesis at the University of Illinois at Urbana-Champaign, randomly selected from light absorption to NADP+ reduction in plants, algae, and cyanobacteria. These include the fact that (i) both the light reactions I and II are powered by light absorbed by chlorophyll (Chl) a of different spectral forms; (ii) light emission (fluorescence, delayed fluorescence, and thermoluminescence) by plants, algae, and cyanobacteria provides detailed information on these reactions and beyond; (iii) primary photochemistry in both the photosystems I (PS I) and II (PS II) occurs within a few picoseconds; and (iv) most importantly, bicarbonate plays a unique role on the electron acceptor side of PS II, specifically at the two-electron gate of PS II. Currently, the ongoing research around the world is, and should be, directed towards making photosynthesis better able to deal with the global issues (such as increasing population, dwindling resources, and rising temperature) particularly through genetic modification. However, basic research is necessary to continue to provide us with an understanding of the molecular mechanism of the process and to guide us in reaching our goals of increasing food production and other chemicals we need for our lives.
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Shibata Y, Mohamed A, Taniyama K, Kanatani K, Kosugi M, Fukumura H. Red shift in the spectrum of a chlorophyll species is essential for the drought-induced dissipation of excess light energy in a poikilohydric moss, Bryum argenteum. PHOTOSYNTHESIS RESEARCH 2018; 136:229-243. [PMID: 29124652 DOI: 10.1007/s11120-017-0461-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 10/27/2017] [Indexed: 06/07/2023]
Abstract
Some mosses are extremely tolerant of drought stress. Their high drought tolerance relies on their ability to effectively dissipate absorbed light energy to heat under dry conditions. The energy dissipation mechanism in a drought-tolerant moss, Bryum argenteum, has been investigated using low-temperature picosecond time-resolved fluorescence spectroscopy. The results are compared between moss thalli samples harvested in Antarctica and in Japan. Both samples show almost the same quenching properties, suggesting an identical drought tolerance mechanism for the same species with two completely different habitats. A global target analysis was applied to a large set of data on the fluorescence-quenching dynamics for the 430-nm (chlorophyll-a selective) and 460-nm (chlorophyll-b and carotenoid selective) excitations in the temperature region from 5 to 77 K. This analysis strongly suggested that the quencher is formed in the major peripheral antenna of photosystem II, whose emission spectrum is significantly broadened and red-shifted in its quenched form. Two emission components at around 717 and 725 nm were assigned to photosystem I (PS I). The former component at around 717 nm is mildly quenched and probably bound to the PS I core complex, while the latter at around 725 nm is probably bound to the light-harvesting complex. The dehydration treatment caused a blue shift of the PS I emission peak via reduction of the exciton energy flow to the pigment responsible for the 725 nm band.
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Affiliation(s)
- Yutaka Shibata
- Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki Aza Aoba, Aoba-Ku, Sendai, 980-8578, Japan.
| | - Ahmed Mohamed
- Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki Aza Aoba, Aoba-Ku, Sendai, 980-8578, Japan
- Institut national de la recherche scientifique (INRS-EMT), Varennes, QC, J3X 1S2, Canada
| | - Koichiro Taniyama
- Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki Aza Aoba, Aoba-Ku, Sendai, 980-8578, Japan
| | - Kentaro Kanatani
- Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki Aza Aoba, Aoba-Ku, Sendai, 980-8578, Japan
| | - Makiko Kosugi
- Department of Biological Science, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-Ku, Tokyo, 112-8551, Japan
| | - Hiroshi Fukumura
- Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki Aza Aoba, Aoba-Ku, Sendai, 980-8578, Japan
- National Institute of Technology, 4-16-1 Ayashi-chuo, Aoba-ku, Sendai, 989-3128, Japan
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Giovagnetti V, Ruban AV. Detachment of the fucoxanthin chlorophyll a/c binding protein (FCP) antenna is not involved in the acclimative regulation of photoprotection in the pennate diatom Phaeodactylum tricornutum. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1858:218-230. [PMID: 27989819 DOI: 10.1016/j.bbabio.2016.12.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 12/04/2016] [Accepted: 12/14/2016] [Indexed: 12/24/2022]
Abstract
When grown under intermittent light (IL), the pennate diatom Phaeodactylum tricornutum forms 'super' non-photochemical fluorescence quenching (NPQ) in response to excess light. The current model of diatom NPQ mechanism involves two quenching sites, one of which detaches from photosystem II reaction centres (RCIIs) and aggregates into oligomeric complexes. Here we addressed how antenna reorganisation controls NPQ kinetics in P. tricornutum cells grown under continuous light (CL) and IL. Overall, IL acclimation induced: (i) reorganisation of chloroplasts, containing greater pigment pools without a strongly enhanced operation of the xanthophyll cycle, and (ii) 'super NPQ' causing a remarkable reduction of the chlorophyll excited state lifetime at Fm'. Regardless of different levels of NPQ formed in both culture conditions, its dark recovery was rapid and similar fractions of their antenna uncoupled (~50%). Although antenna detachment relieved excitation pressure, it provided a minor protective contribution equivalent to NPQ~1, while the largest NPQ was 4.4±0.2 (CL) and 13±0.8 (IL). The PSII cross-section decrease took place only at relatively low NPQ values, beyond which the cross-section remained constant whilst NPQ continued to rise. This finding suggests that the energy trapping efficiency of diatom antenna quenchers cannot over-compete that of RCIIs, similarly to what has been observed on higher plants. We conclude that such 'economic photoprotection' operates to flexibly adjust the overall efficiency of diatom light harvesting.
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Affiliation(s)
- Vasco Giovagnetti
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London, E1 4NS, UK
| | - Alexander V Ruban
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London, E1 4NS, UK.
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11
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Kaňa R, Govindjee. Role of Ions in the Regulation of Light-Harvesting. FRONTIERS IN PLANT SCIENCE 2016; 7:1849. [PMID: 28018387 PMCID: PMC5160696 DOI: 10.3389/fpls.2016.01849] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 11/23/2016] [Indexed: 03/03/2024]
Abstract
Regulation of photosynthetic light harvesting in the thylakoids is one of the major key factors affecting the efficiency of photosynthesis. Thylakoid membrane is negatively charged and influences both the structure and the function of the primarily photosynthetic reactions through its electrical double layer (EDL). Further, there is a heterogeneous organization of soluble ions (K+, Mg2+, Cl-) attached to the thylakoid membrane that, together with fixed charges (negatively charged amino acids, lipids), provides an electrical field. The EDL is affected by the valence of the ions and interferes with the regulation of "state transitions," protein interactions, and excitation energy "spillover" from Photosystem II to Photosystem I. These effects are reflected in changes in the intensity of chlorophyll a fluorescence, which is also a measure of photoprotective non-photochemical quenching (NPQ) of the excited state of chlorophyll a. A triggering of NPQ proceeds via lumen acidification that is coupled to the export of positive counter-ions (Mg2+, K+) to the stroma or/and negative ions (e.g., Cl-) into the lumen. The effect of protons and anions in the lumen and of the cations (Mg2+, K+) in the stroma are, thus, functionally tightly interconnected. In this review, we discuss the consequences of the model of EDL, proposed by Barber (1980b) Biochim Biophys Acta 594:253-308) in light of light-harvesting regulation. Further, we explain differences between electrostatic screening and neutralization, and we emphasize the opposite effect of monovalent (K+) and divalent (Mg2+) ions on light-harvesting and on "screening" of the negative charges on the thylakoid membrane; this effect needs to be incorporated in all future models of photosynthetic regulation by ion channels and transporters.
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Affiliation(s)
- Radek Kaňa
- Institute of Microbiology, Academy of Sciences of the CzechiaTřeboň, Czechia
- Faculty of Science, Institute of Chemistry and Biochemistry, University of South BohemiaČeské Budějovice, Czechia
| | - Govindjee
- Center of Biophysics and Quantitative Biology, Department of Biochemistry, Department of Plant Biology, University of Illinois at Urbana-ChampaignUrbana, IL, USA
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Liguori N, Natali A, Croce R. Engineering a pH-Regulated Switch in the Major Light-Harvesting Complex of Plants (LHCII): Proof of Principle. J Phys Chem B 2016; 120:12531-12535. [PMID: 27973840 DOI: 10.1021/acs.jpcb.6b11541] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Under excess light, photosynthetic organisms employ feedback mechanisms to avoid photodamage. Photoprotection is triggered by acidification of the lumen of the photosynthetic membrane following saturation of the metabolic activity. A low pH triggers thermal dissipation of excess absorbed energy by the light-harvesting complexes (LHCs). LHCs are not able to sense pH variations, and their switch to a dissipative mode depends on stress-related proteins and allosteric cofactors. In green algae the trigger is the pigment-protein complex LHCSR3. Its C-terminus is responsible for a pH-driven conformational change from a light-harvesting to a quenched state. Here, we show that by replacing the C-terminus of the main LHC of plants with that of LHCSR3, it is possible to regulate its excited-state lifetime solely via protonation, demonstrating that the protein template of LHCs can be modified to activate reversible quenching mechanisms independent of external cofactors and triggers.
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Affiliation(s)
- Nicoletta Liguori
- Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics, Faculty of Sciences, VU University Amsterdam , De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Alberto Natali
- Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics, Faculty of Sciences, VU University Amsterdam , De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Roberta Croce
- Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics, Faculty of Sciences, VU University Amsterdam , De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
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LHCSR1 induces a fast and reversible pH-dependent fluorescence quenching in LHCII in Chlamydomonas reinhardtii cells. Proc Natl Acad Sci U S A 2016; 113:7673-8. [PMID: 27335457 DOI: 10.1073/pnas.1605380113] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To avoid photodamage, photosynthetic organisms are able to thermally dissipate the energy absorbed in excess in a process known as nonphotochemical quenching (NPQ). Although NPQ has been studied extensively, the major players and the mechanism of quenching remain debated. This is a result of the difficulty in extracting molecular information from in vivo experiments and the absence of a validation system for in vitro experiments. Here, we have created a minimal cell of the green alga Chlamydomonas reinhardtii that is able to undergo NPQ. We show that LHCII, the main light harvesting complex of algae, cannot switch to a quenched conformation in response to pH changes by itself. Instead, a small amount of the protein LHCSR1 (light-harvesting complex stress related 1) is able to induce a large, fast, and reversible pH-dependent quenching in an LHCII-containing membrane. These results strongly suggest that LHCSR1 acts as pH sensor and that it modulates the excited state lifetimes of a large array of LHCII, also explaining the NPQ observed in the LHCSR3-less mutant. The possible quenching mechanisms are discussed.
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Possible role of interference, protein noise, and sink effects in nonphotochemical quenching in photosynthetic complexes. J Math Biol 2016; 74:43-76. [DOI: 10.1007/s00285-016-1016-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 04/08/2016] [Indexed: 10/21/2022]
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Kristoffersen AS, Hamre B, Frette Ø, Erga SR. Chlorophyll a fluorescence lifetime reveals reversible UV-induced photosynthetic activity in the green algae Tetraselmis. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2015; 45:259-68. [PMID: 26538330 PMCID: PMC4796335 DOI: 10.1007/s00249-015-1092-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 10/07/2015] [Accepted: 10/13/2015] [Indexed: 11/30/2022]
Abstract
The fluorescence lifetime is a very useful parameter for investigating biological materials on the molecular level as it is mostly independent of the fluorophore concentration. The green alga Tetraselmis blooms in summer, and therefore its response to UV irradiation is of particular interest. In vivo fluorescence lifetimes of chlorophyll a were measured under both normal and UV-stressed conditions of Tetraselmis. Fluorescence was induced by two-photon excitation using a femtosecond laser and laser scanning microscope. The lifetimes were measured in the time domain by time-correlated single-photon counting. Under normal conditions, the fluorescence lifetime was 262 ps, while after 2 h of exposure to UV radiation the lifetime increased to 389 ps, indicating decreased photochemical quenching, likely caused by a damaged and down-regulated photosynthetic apparatus. This was supported by a similar increase in the lifetime to 425 ps when inhibiting photosynthesis chemically using DCMU. Furthermore, the UV-stressed sample was dark-adapted overnight, resulting in a return of the lifetime to 280 ps, revealing that the damage caused by UV radiation is repairable on a relatively short time scale. This reversal of photosynthetic activity was also confirmed by [Formula: see text] measurements.
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Affiliation(s)
- Arne S Kristoffersen
- Department of Physics and Technology, University of Bergen, P.O. Box 7803, 5020, Bergen, Norway.
| | - Børge Hamre
- Department of Physics and Technology, University of Bergen, P.O. Box 7803, 5020, Bergen, Norway
| | - Øyvind Frette
- Department of Physics and Technology, University of Bergen, P.O. Box 7803, 5020, Bergen, Norway
| | - Svein R Erga
- Department of Biology, University of Bergen, P.O. Box 7803, 5020, Bergen, Norway
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Candotto Carniel F, Zanelli D, Bertuzzi S, Tretiach M. Desiccation tolerance and lichenization: a case study with the aeroterrestrial microalga Trebouxia sp. (Chlorophyta). PLANTA 2015; 242:493-505. [PMID: 25998523 DOI: 10.1007/s00425-015-2319-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 05/04/2015] [Indexed: 06/04/2023]
Abstract
A comparative study of isolated vs. lichenized Trebouxia sp. showed that lichenization does not influence the survival capability of the alga to the photo-oxidative stress derived from prolonged desiccation. Coccoid algae in the Trebouxia genus are the most common photobionts of chlorolichens but are only sporadically found in soil or bark outside of a lichen. They all appear to be desiccation tolerant, i.e. they can survive drying to water contents of below 10%. However, little is known about their longevity in the dry state and to which extent lichenization can influence it. Here, we studied the longevity in the dry state of the lichenized alga (LT) Trebouxia sp. in the lichen Parmotrema perlatum, in comparison with axenically grown cultures (CT) isolated from the same lichen. We report on chlorophyll fluorescence emission and reactive oxygen species (ROS) production before desiccation, after 15-45 days in the dry state under different combinations of light and air humidity and after recovery for 1 or 3 days in fully hydrated conditions. Both the CT and the LT were able to withstand desiccation under high light (120 µmol photons m(-2) s(-1) for 14 h per day), but upon recovery after 45 days in the dry state the performance of the CT was better than that of the LT. By contrast, the quenching of excess light energy was more efficient in the LT, at high relative humidities especially. ROS production in the LT was influenced mostly by light exposure, whereas the CT showed an oxidative burst independent of the light conditions. Although lichenization provides benefits that are essential for the survival of the photobiont in high-light habitats, Trebouxia sp. can withstand protracted periods of photo-oxidative stress even outside of a lichen thallus.
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Affiliation(s)
- Fabio Candotto Carniel
- Dipartimento di Scienze della Vita, Università degli Studi di Trieste, Via L. Giorgieri, 10, 34127, Trieste, Italy,
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Stirbet A, Riznichenko GY, Rubin AB, Govindjee. Modeling chlorophyll a fluorescence transient: relation to photosynthesis. BIOCHEMISTRY (MOSCOW) 2015; 79:291-323. [PMID: 24910205 DOI: 10.1134/s0006297914040014] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
To honor Academician Alexander Abramovitch Krasnovsky, we present here an educational review on the relation of chlorophyll a fluorescence transient to various processes in photosynthesis. The initial event in oxygenic photosynthesis is light absorption by chlorophylls (Chls), carotenoids, and, in some cases, phycobilins; these pigments form the antenna. Most of the energy is transferred to reaction centers where it is used for charge separation. The small part of energy that is not used in photochemistry is dissipated as heat or re-emitted as fluorescence. When a photosynthetic sample is transferred from dark to light, Chl a fluorescence (ChlF) intensity shows characteristic changes in time called fluorescence transient, the OJIPSMT transient, where O (the origin) is for the first measured minimum fluorescence level; J and I for intermediate inflections; P for peak; S for semi-steady state level; M for maximum; and T for terminal steady state level. This transient is a real signature of photosynthesis, since diverse events can be related to it, such as: changes in redox states of components of the linear electron transport flow, involvement of alternative electron routes, the build-up of a transmembrane pH gradient and membrane potential, activation of different nonphotochemical quenching processes, activation of the Calvin-Benson cycle, and other processes. In this review, we present our views on how different segments of the OJIPSMT transient are influenced by various photosynthetic processes, and discuss a number of studies involving mathematical modeling and simulation of the ChlF transient. A special emphasis is given to the slower PSMT phase, for which many studies have been recently published, but they are less known than on the faster OJIP phase.
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Affiliation(s)
- A Stirbet
- 204 Anne Burras Lane, Newport News, VA 23606, USA.
| | | | | | - Govindjee
- Department of Plant Biology, Department of Biochemistry and Center of Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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Zulfugarov IS, Tovuu A, Lee CH. Acceleration of cyclic electron flow in rice plants (Oryza sativa L.) deficient in the PsbS protein of Photosystem II. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 84:233-239. [PMID: 25306526 DOI: 10.1016/j.plaphy.2014.10.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 10/01/2014] [Indexed: 05/08/2023]
Abstract
When compared with Photosystem I (PSI) in wild-type (WT) rice plants, PSI in PsbS-knockout (KO) plants that lack the energy-dependent component of nonphotochemical quenching (NPQ) was less sensitive to photoinhibition. Therefore, we investigated the relationship between NPQ and cyclic electron flow (CEF) around PSI as a photoprotective mechanism. Activities of two CEF routes (PGR5-dependent or NDH-dependent) were compared between those genotypes by using both dark-adapted plants and pre-illuminated plants, i.e., those in which the Calvin-Benson cycle is de-activated and activated, respectively. In dark-adapted leaves activity of the PGR5-dependent route was determined as the rate of P700 photooxidation. Activity was higher in the mutants than in the WT. However, no difference was noted when plants of either genotype were pre-illuminated. When the electron transport pathway was switched to the cyclic mode by infiltrating leaf segments with 150 mM sorbitol, 40 μM DCMU, and 2 mM hydroxylamine, the rate of P700 oxidation was faster in the mutant. That difference disappeared when leaves were infiltrated with antimycin A to inhibit the PGR5-dependent route. Chlorophyll fluorescence (Fo) was also evaluated. To achieve an Fo level comparable to that of the WT, activation of the NDH-dependent route in the mutant required pre-illumination at a certain dose. Therefore, we propose that, as an alternate pathway for the photoprotection of photosystems in the absence of energy-dependent quenching, this PGR5-dependent route is more highly activated in the PsbS-KO mutants than in the WT. Moreover, that stronger activity is probably responsible for slower activation of the NDH-dependent route in the mutant.
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Affiliation(s)
- Ismayil S Zulfugarov
- Department of Integrated Biological Science, Department of Molecular Biology, Pusan National University, Jangjeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea; Department of Biology, North-Eastern Federal University, 58 Belinsky Str., Yakutsk 677-027 Republic of Sakha (Yakutia), Russian Federation; Institute of Botany, Azerbaijan National Academy of Sciences, Patamdar Shosse 40, Baku, AZ 1073, Azerbaijan.
| | - Altanzaya Tovuu
- Department of Integrated Biological Science, Department of Molecular Biology, Pusan National University, Jangjeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea; Department of Biology, Mongolian State University of Agriculture, Zaisan, 17024 Ulaanbaatar, Mongolia.
| | - Choon-Hwan Lee
- Department of Integrated Biological Science, Department of Molecular Biology, Pusan National University, Jangjeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea.
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Zulfugarov IS, Tovuu A, Eu YJ, Dogsom B, Poudyal RS, Nath K, Hall M, Banerjee M, Yoon UC, Moon YH, An G, Jansson S, Lee CH. Production of superoxide from Photosystem II in a rice (Oryza sativa L.) mutant lacking PsbS. BMC PLANT BIOLOGY 2014; 14:242. [PMID: 25342550 PMCID: PMC4219129 DOI: 10.1186/s12870-014-0242-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 09/08/2014] [Indexed: 05/05/2023]
Abstract
BACKGROUND PsbS is a 22-kDa Photosystem (PS) II protein involved in non-photochemical quenching (NPQ) of chlorophyll fluorescence. Rice (Oryza sativa L.) has two PsbS genes, PsbS1 and PsbS2. However, only inactivation of PsbS1, through a knockout (PsbS1-KO) or in RNAi transgenic plants, results in plants deficient in qE, the energy-dependent component of NPQ. RESULTS In studies presented here, under fluctuating high light, growth of young seedlings lacking PsbS is retarded, and PSII in detached leaves of the mutants is more sensitive to photoinhibitory illumination compared with the wild type. Using both histochemical and fluorescent probes, we determined the levels of reactive oxygen species, including singlet oxygen, superoxide, and hydrogen peroxide, in leaves and thylakoids. The PsbS-deficient plants generated more superoxide and hydrogen peroxide in their chloroplasts. PSII complexes isolated from them produced more superoxide compared with the wild type, and PSII-driven superoxide production was higher in the mutants. However, we could not observe such differences either in isolated PSI complexes or through PSI-driven electron transport. Time-course experiments using isolated thylakoids showed that superoxide production was the initial event, and that production of hydrogen peroxide proceeded from that. CONCLUSION These results indicate that at least some of the photoprotection provided by PsbS and qE is mediated by preventing production of superoxide released from PSII under conditions of excess excitation energy.
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Affiliation(s)
- Ismayil S Zulfugarov
- />Department of Integrated Biological Science and Department of Molecular Biology, Pusan National University, Busan, 609-735 Korea
- />Department of Biology, North-Eastern Federal University, 58 Belinsky Str, Yakutsk, 677-027 Republic of Sakha (Yakutia) Russian Federation
- />Institute of Botany, Azerbaijan National Academy of Sciences, Patamdar Shosse 40, Baku, AZ 1073 Azerbaijan
| | - Altanzaya Tovuu
- />Department of Integrated Biological Science and Department of Molecular Biology, Pusan National University, Busan, 609-735 Korea
- />Department of Biology, Mongolian State University of Agriculture, Zaisan, Ulaanbaatar, 17024 Mongolia
| | - Young-Jae Eu
- />Department of Integrated Biological Science and Department of Molecular Biology, Pusan National University, Busan, 609-735 Korea
| | - Bolormaa Dogsom
- />Department of Integrated Biological Science and Department of Molecular Biology, Pusan National University, Busan, 609-735 Korea
| | - Roshan Sharma Poudyal
- />Department of Integrated Biological Science and Department of Molecular Biology, Pusan National University, Busan, 609-735 Korea
| | - Krishna Nath
- />Department of Integrated Biological Science and Department of Molecular Biology, Pusan National University, Busan, 609-735 Korea
| | - Michael Hall
- />Umeå Plant Science Center, Department of Plant Physiology, Umeå University, Umeå, SE-901 87 Sweden
| | - Mainak Banerjee
- />Department of Chemistry, Pusan National University, Jangjeon-dong, Keumjung-gu, Busan, 609-735 Korea
| | - Ung Chan Yoon
- />Department of Chemistry, Pusan National University, Jangjeon-dong, Keumjung-gu, Busan, 609-735 Korea
| | - Yong-Hwan Moon
- />Department of Integrated Biological Science and Department of Molecular Biology, Pusan National University, Busan, 609-735 Korea
| | - Gynheung An
- />Crop Biotech Institute, Kyung Hee University, Yongin, 446-701 Korea
| | - Stefan Jansson
- />Umeå Plant Science Center, Department of Plant Physiology, Umeå University, Umeå, SE-901 87 Sweden
| | - Choon-Hwan Lee
- />Department of Integrated Biological Science and Department of Molecular Biology, Pusan National University, Busan, 609-735 Korea
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Correia RF, Viseu MI, Andrade SM. Aggregation/disaggregation of chlorophyll a in model phospholipid-detergent vesicles and micelles. Photochem Photobiol Sci 2014; 13:907-16. [PMID: 24715103 DOI: 10.1039/c3pp50419k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The photosynthetic pigments of higher plants exist in complex oligomeric states, which are difficult to study in vivo. To investigate aggregation processes of chlorophyll a (Chl a), we used an in vitro reconstitution procedure, with this pigment incorporated into liposomes of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), micelles and pre-micelle media of the detergent n-dodecyltrimethylammonium chloride (DTAC), and mixed, spontaneous, DMPC-DTAC vesicles and micelles. Chl a oligomers were characterized by UV-visible absorption, steady-state and time-resolved fluorescence, and fluorescence lifetime imaging microscopy. Equivalent diameters of the colloidal structures were obtained by fluorescence correlation spectroscopy. In DMPC liposomes and DMPC-DTAC vesicles and micelles, three fluorescence lifetimes indicated the coexistence of Chl a monomers (≈5 ns) and oligomers (≈1-2 to ≈0.1 ns). The increase in DTAC amount, in the mixed system, induces a progressive solubilization of DMPC liposomes (from vesicles to micelles) and simultaneous disruption of Chl a aggregates; in pure DTAC micelles, mostly monomers were found. The present work aims for a better understanding of chlorophyll-chlorophyll (Chl-Chl), Chl-lipid, and Chl-detergent interactions in spontaneous colloidal micro- and nanostructures.
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Affiliation(s)
- Raquel F Correia
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal.
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21
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Subashchandrabose S, Krishnan K, Gratton E, Megharaj M, Naidu R. Potential of fluorescence imaging techniques to monitor mutagenic PAH uptake by microalga. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:9152-9160. [PMID: 25020149 PMCID: PMC4140530 DOI: 10.1021/es500387v] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 07/14/2014] [Accepted: 07/14/2014] [Indexed: 05/30/2023]
Abstract
Benzo[a]pyrene (BaP), a polycyclic aromatic hydrocarbon (PAH), is one of the major environmental pollutants that causes mutagenesis and cancer. BaP has been shown to accumulate in phytoplankton and zooplankton. We have studied the localization and aggregation of BaP in Chlorella sp., a microalga that is one of the primary producers in the food chain, using fluorescence confocal microscopy and fluorescence lifetime imaging microscopy with the phasor approach to characterize the location and the aggregation of BaP in the cell. Our results show that BaP accumulates in the lipid bodies of Chlorella sp. and that there is Förster resonance energy transfer between BaP and photosystems of Chlorella sp., indicating the close proximity of the two molecular systems. The lifetime of BaP fluorescence was measured to be 14 ns in N,N-dimethylformamide, an average of 7 ns in Bold's basal medium, and 8 ns in Chlorella cells. Number and brightness analysis suggests that BaP does not aggregate inside Chlorella sp. (average brightness = 5.330), while it aggregates in the supernatant. In Chlorella grown in sediments spiked with BaP, in 12 h the BaP uptake could be visualized using fluorescence microscopy.
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Affiliation(s)
- Suresh
Ramraj Subashchandrabose
- Centre
for Environmental Risk Assessment and Remediation, University of South Australia and CRC CARE, Mawson Lakes, Adelaide, South Australia 5095, Australia
| | - Kannan Krishnan
- Centre
for Environmental Risk Assessment and Remediation, University of South Australia and CRC CARE, Mawson Lakes, Adelaide, South Australia 5095, Australia
| | - Enrico Gratton
- Laboratory
for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, California 92697, United States
| | - Mallavarapu Megharaj
- Centre
for Environmental Risk Assessment and Remediation, University of South Australia and CRC CARE, Mawson Lakes, Adelaide, South Australia 5095, Australia
| | - Ravi Naidu
- Centre
for Environmental Risk Assessment and Remediation, University of South Australia and CRC CARE, Mawson Lakes, Adelaide, South Australia 5095, Australia
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Porcar-Castell A, Tyystjärvi E, Atherton J, van der Tol C, Flexas J, Pfündel EE, Moreno J, Frankenberg C, Berry JA. Linking chlorophyll a fluorescence to photosynthesis for remote sensing applications: mechanisms and challenges. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:4065-95. [PMID: 24868038 DOI: 10.1093/jxb/eru191] [Citation(s) in RCA: 283] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Chlorophyll a fluorescence (ChlF) has been used for decades to study the organization, functioning, and physiology of photosynthesis at the leaf and subcellular levels. ChlF is now measurable from remote sensing platforms. This provides a new optical means to track photosynthesis and gross primary productivity of terrestrial ecosystems. Importantly, the spatiotemporal and methodological context of the new applications is dramatically different compared with most of the available ChlF literature, which raises a number of important considerations. Although we have a good mechanistic understanding of the processes that control the ChlF signal over the short term, the seasonal link between ChlF and photosynthesis remains obscure. Additionally, while the current understanding of in vivo ChlF is based on pulse amplitude-modulated (PAM) measurements, remote sensing applications are based on the measurement of the passive solar-induced chlorophyll fluorescence (SIF), which entails important differences and new challenges that remain to be solved. In this review we introduce and revisit the physical, physiological, and methodological factors that control the leaf-level ChlF signal in the context of the new remote sensing applications. Specifically, we present the basis of photosynthetic acclimation and its optical signals, we introduce the physical and physiological basis of ChlF from the molecular to the leaf level and beyond, and we introduce and compare PAM and SIF methodology. Finally, we evaluate and identify the challenges that still remain to be answered in order to consolidate our mechanistic understanding of the remotely sensed SIF signal.
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Affiliation(s)
- Albert Porcar-Castell
- Department of Forest Sciences, University of Helsinki, PO Box 27, 00014 Helsinki, Finland
| | - Esa Tyystjärvi
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Jon Atherton
- Department of Forest Sciences, University of Helsinki, PO Box 27, 00014 Helsinki, Finland
| | | | - Jaume Flexas
- Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Ctra. de Valldemossa Km. 7.5, 07122 Palma, Spain
| | | | - Jose Moreno
- Department of Earth Physics and Thermodynamics, Faculty of Physics, University of Valencia, C/ Dr. Moliner, 50, 46100 Burjassot, Valencia, Spain
| | - Christian Frankenberg
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Joseph A Berry
- Department of Global Ecology, Carnegie Institution of Washington, Stanford, CA 94305, USA
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Adams WW, Demmig-Adams B. Lessons from Nature: A Personal Perspective. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2014. [DOI: 10.1007/978-94-017-9032-1_2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Non-Photochemical Quenching Mechanisms in Intact Organisms as Derived from Ultrafast-Fluorescence Kinetic Studies. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2014. [DOI: 10.1007/978-94-017-9032-1_5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Ostroumov EE, Khan YR, Scholes GD, Govindjee. Photophysics of Photosynthetic Pigment-Protein Complexes. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2014. [DOI: 10.1007/978-94-017-9032-1_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Magdaong NM, Enriquez MM, LaFountain AM, Rafka L, Frank HA. Effect of protein aggregation on the spectroscopic properties and excited state kinetics of the LHCII pigment–protein complex from green plants. PHOTOSYNTHESIS RESEARCH 2013; 118:259-76. [PMID: 24077891 DOI: 10.1007/s11120-013-9924-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 09/09/2013] [Indexed: 05/15/2023]
Abstract
Steady-state and time-resolved absorption and fluorescence spectroscopic experiments have been carried out at room and cryogenic temperatures on aggregated and unaggregated monomeric and trimeric LHCII complexes isolated from spinach chloroplasts. Protein aggregation has been hypothesized to be one of the mechanistic factors controlling the dissipation of excess photo-excited state energy of chlorophyll during the process known as nonphotochemical quenching. The data obtained from the present experiments reveal the role of protein aggregation on the spectroscopic properties and dynamics of energy transfer and excited state deactivation of the protein-bound chlorophyll and carotenoid pigments.
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Eaton-Rye JJ. Govindjee at 80: more than 50 years of free energy for photosynthesis. PHOTOSYNTHESIS RESEARCH 2013; 116:111-44. [PMID: 24113923 DOI: 10.1007/s11120-013-9921-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 08/26/2013] [Indexed: 05/23/2023]
Abstract
We provide here a glimpse of Govindjee and his pioneering contributions on the two light reactions and the two pigment systems, particularly on the water-plastoquinone oxido-reductase, Photosystem II. His focus has been on excitation energy transfer; primary photochemistry, and the role of bicarbonate in electron and proton transfer. His major tools have been kinetics and spectroscopy (absorption and fluorescence), and he has provided an understanding of both thermoluminescence and delayed light emission in plants and algae. He pioneered the use of lifetime of fluorescence measurements to study the phenomenon of photoprotection in plants and algae. He, however, is both a generalist and a specialist all at the same time. He communicates very effectively his passion for photosynthesis to the novice as well as professionals. He has been a prolific author, outstanding lecturer and an editor par excellence. He is the founder not only of the Historical Corner of Photosynthesis Research, but of the highly valued Series Advances in Photosynthesis and Respiration Including Bioenergy and Related Processes. He reaches out to young people by distributing Z-scheme posters, presenting Awards of books, and through tri-annual articles on "Photosynthesis Web Resources". At home, at the University of Illinois at Urbana-Champaign, he has established student Awards for Excellence in Biological Sciences. On behalf of all his former graduate students and associates, I wish him a Happy 80th birthday. I have included here several tributes to Govindjee by his well-wishers. These write-ups express the high regard the photosynthesis community holds for "Gov" and illuminate the different facets of his life and associations.
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Affiliation(s)
- Julian J Eaton-Rye
- Department of Biochemistry, University of Otago, P.O. Box 56, Dunedin, 9054, New Zealand,
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Zaks J, Amarnath K, Sylak-Glassman EJ, Fleming GR. Models and measurements of energy-dependent quenching. PHOTOSYNTHESIS RESEARCH 2013; 116:389-409. [PMID: 23793348 PMCID: PMC3824227 DOI: 10.1007/s11120-013-9857-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 05/21/2013] [Indexed: 05/18/2023]
Abstract
Energy-dependent quenching (qE) in photosystem II (PSII) is a pH-dependent response that enables plants to regulate light harvesting in response to rapid fluctuations in light intensity. In this review, we aim to provide a physical picture for understanding the interplay between the triggering of qE by a pH gradient across the thylakoid membrane and subsequent changes in PSII. We discuss how these changes alter the energy transfer network of chlorophyll in the grana membrane and allow it to switch between an unquenched and quenched state. Within this conceptual framework, we describe the biochemical and spectroscopic measurements and models that have been used to understand the mechanism of qE in plants with a focus on measurements of samples that perform qE in response to light. In addition, we address the outstanding questions and challenges in the field. One of the current challenges in gaining a full understanding of qE is the difficulty in simultaneously measuring both the photophysical mechanism of quenching and the physiological state of the thylakoid membrane. We suggest that new experimental and modeling efforts that can monitor the many processes that occur on multiple timescales and length scales will be important for elucidating the quantitative details of the mechanism of qE.
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Affiliation(s)
- Julia Zaks
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 USA
- Graduate Group in Applied Science and Technology, University of California, Berkeley, CA 94720 USA
| | - Kapil Amarnath
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 USA
- Department of Chemistry, University of California at Berkeley, Berkeley, CA 94720 USA
| | - Emily J. Sylak-Glassman
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 USA
- Department of Chemistry, University of California at Berkeley, Berkeley, CA 94720 USA
| | - Graham R. Fleming
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 USA
- Graduate Group in Applied Science and Technology, University of California, Berkeley, CA 94720 USA
- Department of Chemistry, University of California at Berkeley, Berkeley, CA 94720 USA
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Slavov C, Reus M, Holzwarth AR. Two different mechanisms cooperate in the desiccation-induced excited state quenching in Parmelia lichen. J Phys Chem B 2013; 117:11326-36. [PMID: 23841476 DOI: 10.1021/jp402881f] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The highly efficient desiccation-induced quenching in the poikilohydric lichen Parmelia sulcata has been studied by ultrafast fluorescence spectroscopy at room temperature (r.t.) and cryogenic temperatures in order to elucidate the quenching mechanism(s) and kinetic reaction models. Analysis of the r.t. data by kinetic target analysis reveals that two different quenching mechanisms contribute to the protection of photosystem II (PS II). The first mechanism is a direct quenching of the PS II antenna and is related to the characteristic F740 nm fluorescence band. Based on the temperature dependence of its spectra and the kinetics, this mechanism is proposed to reflect the formation of a fluorescent (F740) chlorophyll-chlorophyll charge-transfer state. It is discussed in relation to a similar fluorescence band and quenching mechanism observed in light-induced nonphotochemical quenching in higher plants. The second and more efficient quenching process (providing more than 70% of the total PS II quenching) is shown to involve an efficient spillover (energy transfer) from PS II to PS I which can be prevented by a short glutaraldehyde treatment. Desiccation causes a thylakoid-membrane rearrangement which brings into direct contact the PS II and PS I units. The energy transferred to PS I in the spillover process is then quenched highly efficiently in PS I due to the formation of a long-lived P700(+) state in the dried state in the light. As a consequence, both PS II and PS I are protected very efficiently against photodestruction. This dual quenching mechanism is supported by the low temperature kinetics data.
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Affiliation(s)
- Chavdar Slavov
- Max Planck Institute for Chemical Energy Conversion , D-45470 Mülheim a.d. Ruhr, Germany
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Chen L, Huang L, Li X, You S, Yang S, Zhang Y, Wang W. Water and nutrient relationships between a mistletoe and its mangrove host under saline conditions. FUNCTIONAL PLANT BIOLOGY : FPB 2013; 40:475-483. [PMID: 32481124 DOI: 10.1071/fp12218] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 12/18/2012] [Indexed: 06/11/2023]
Abstract
Xylem-tapping mistletoes are known to have generally higher transpiration rate (Tr), lower CO2 assimilation rate (A) and therefore lower water-use efficiency (WUE) than their hosts. There are long-standing contradictions in water relations and nitrogen use in photosynthesis. Gas exchange, chlorophyll fluorescence and nutrition components were investigated in a special mistletoe-host pair, Viscum ovalifolium-Sonneratia caseolaris, as the host was a mangrove growing in a saline environment. Our results show that both plants had high foliar N content, therefore it was consistent with the N-parasitism hypothesis, although the mistletoe had a lower Tr than its mangrove host. It was suggested that the mistletoe reduces its Tr under salt stress with N sufficient conditions. The mistletoe had a fundamental limitation of photosynthesis, and was photoinhibited with regard to high salinity, but it developed more photoprotection to thermal radiation. Additionally, both stomatal conductance (gs) and mesophyll conductance (gm) limitations on photosynthesis dominated in the mistletoe under salt stress even though it had a high foliar N content similar to the host.
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Affiliation(s)
- Luzhen Chen
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen 361005, Fujian, PR China
| | - Li Huang
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen 361005, Fujian, PR China
| | - Xiaofei Li
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen 361005, Fujian, PR China
| | - Siyang You
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen 361005, Fujian, PR China
| | - Shengchang Yang
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen 361005, Fujian, PR China
| | - Yihui Zhang
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen 361005, Fujian, PR China
| | - Wenqing Wang
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen 361005, Fujian, PR China
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Ocampo-Alvarez H, García-Mendoza E, Govindjee. Antagonist effect between violaxanthin and de-epoxidated pigments in nonphotochemical quenching induction in the qE deficient brown alga Macrocystis pyrifera. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1827:427-37. [PMID: 23287384 DOI: 10.1016/j.bbabio.2012.12.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 12/13/2012] [Accepted: 12/14/2012] [Indexed: 01/24/2023]
Abstract
Nonphotochemical quenching (NPQ) of Photosystem II fluorescence is one of the most important photoprotection responses of phototropic organisms. NPQ in Macrocystis pyrifera is unique since the fast induction of this response, the energy dependent quenching (qE), is not present in this alga. In contrast to higher plants, NPQ in this organism is much more strongly related to xanthophyll cycle (XC) pigment interconversion. Characterization of how NPQ is controlled when qE is not present is important as this might represent an ancient response to light stress. Here, we describe the influence of the XC pigment pool (ΣXC) size on NPQ induction in M. pyrifera. The sum of violaxanthin (Vx) plus antheraxanthin and zeaxanthin (Zx) represents the ΣXC. This pool was three-fold larger in blades collected at the surface of the water column (19molmol(-1) Chl a×100) than in blades collected at 6m depth. Maximum NPQ was not different in samples with a ΣXC higher than 12molmol(-1) Chl a×100; however, NPQ induction was faster in blades with a large ΣXC. The increase in the NPQ induction rate was associated with a faster Vx to Zx conversion. Further, we found that NPQ depends on the de-epoxidation state of the ΣXC, not on the absolute concentration of Zx and antheraxanthin. Thus, there was an antagonist effect between Vx and de-epoxidated xanthophylls for NPQ. These results indicate that in the absence of qE, a large ΣXC is needed in M. pyrifera to respond faster to light stress conditions.
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Affiliation(s)
- Héctor Ocampo-Alvarez
- Departamento de Oceanografía Biológica, Centro de Investigación Científica y de Educación Superior de Ensenada, Baja California, México.
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Zeng Y, Wu Y, Li D, Zheng W, Wang WX, Qu JY. Two-photon excitation chlorophyll fluorescence lifetime imaging: a rapid and noninvasive method for in vivo assessment of cadmium toxicity in a marine diatom Thalassiosira weissflogii. PLANTA 2012; 236:1653-1663. [PMID: 22806228 DOI: 10.1007/s00425-012-1703-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2012] [Accepted: 06/24/2012] [Indexed: 06/01/2023]
Abstract
We demonstrate that a two-photon excitation fluorescence lifetime imaging technology can rapidly and noninvasively assess the cadmium (Cd)-induced toxic effects in a marine diatom Thalassiosira weissflogii. The chlorophyll, an intrinsic fluorophore, was used as a contrast agent for imaging of cellular structures and for assessment of cell toxicity. The assessment is based on an imaging-guided statistical analysis of chlorophyll fluorescence decay. This novel label-free imaging method is physically based and free of tedious preparation and preprocessing of algal samples. We first studied the chlorophyll fluorescence quenching induced by the infrared two-photon excitation laser and found that the quenching effects on the assessment of Cd toxicity could be well controlled and calibrated. In the toxicity study, chlorophyll fluorescence lifetime images were collected from the diatom samples after exposure to different concentrations of Cd. The alteration of chloroplast structure at higher Cd concentration was clearly identified. The decay of chlorophyll fluorescence extracted from recorded pixels of high signal-to-noise ratio in the fluorescence lifetime image was analyzed. The increase of average chlorophyll fluorescence lifetime following Cd treatment was observed, indicating the Cd inhibition effect on the electron transport chain in photosynthesis system. The findings of this study show that the temporal characteristics of chlorophyll fluorescence can potentially be utilized as a biomarker for indicating Cd toxicity noninvasively in algal cells.
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Affiliation(s)
- Yan Zeng
- Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People's Republic of China.
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Belgio E, Johnson M, Jurić S, Ruban A. Higher plant photosystem II light-harvesting antenna, not the reaction center, determines the excited-state lifetime-both the maximum and the nonphotochemically quenched. Biophys J 2012; 102:2761-71. [PMID: 22735526 PMCID: PMC3379028 DOI: 10.1016/j.bpj.2012.05.004] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 05/02/2012] [Accepted: 05/07/2012] [Indexed: 11/28/2022] Open
Abstract
The maximum chlorophyll fluorescence lifetime in isolated photosystem II (PSII) light-harvesting complex (LHCII) antenna is 4 ns; however, it is quenched to 2 ns in intact thylakoid membranes when PSII reaction centers (RCIIs) are closed (Fm). It has been proposed that the closed state of RCIIs is responsible for the quenching. We investigated this proposal using a new, to our knowledge, model system in which the concentration of RCIIs was highly reduced within the thylakoid membrane. The system was developed in Arabidopsis thaliana plants under long-term treatment with lincomycin, a chloroplast protein synthesis inhibitor. The treatment led to 1), a decreased concentration of RCIIs to 10% of the control level and, interestingly, an increased antenna component; 2), an average reduction in the yield of photochemistry to 0.2; and 3), an increased nonphotochemical chlorophyll fluorescence quenching (NPQ). Despite these changes, the average fluorescence lifetimes measured in Fm and Fm' (with NPQ) states were nearly identical to those obtained from the control. A 77 K fluorescence spectrum analysis of treated PSII membranes showed the typical features of preaggregation of LHCII, indicating that the state of LHCII antenna in the dark-adapted photosynthetic membrane is sufficient to determine the 2 ns Fm lifetime. Therefore, we conclude that the closed RCs do not cause quenching of excitation in the PSII antenna, and play no role in the formation of NPQ.
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Affiliation(s)
- Erica Belgio
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Matthew P. Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Snježana Jurić
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Alexander V. Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
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Fluorescence lifetime snapshots reveal two rapidly reversible mechanisms of photoprotection in live cells of Chlamydomonas reinhardtii. Proc Natl Acad Sci U S A 2012; 109:8405-10. [PMID: 22586081 DOI: 10.1073/pnas.1205303109] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Photosynthetic organisms avoid photodamage to photosystem II (PSII) in variable light conditions via a suite of photoprotective mechanisms called nonphotochemical quenching (NPQ), in which excess absorbed light is dissipated harmlessly. To quantify the contributions of different quenching mechanisms to NPQ, we have devised a technique to measure the changes in chlorophyll fluorescence lifetime as photosynthetic organisms adapt to varying light conditions. We applied this technique to measure the fluorescence lifetimes responsible for the predominant, rapidly reversible component of NPQ, qE, in living cells of Chlamydomonas reinhardtii. Application of high light to dark-adapted cells of C. reinhardtii led to an increase in the amplitudes of 65 ps and 305 ps chlorophyll fluorescence lifetime components that was reversed after the high light was turned off. Removal of the pH gradient across the thylakoid membrane linked the changes in the amplitudes of the two components to qE quenching. The rise times of the amplitudes of the two components were significantly different, suggesting that the changes are due to two different qE mechanisms. We tentatively suggest that the changes in the 65 ps component are due to charge-transfer quenching in the minor light-harvesting complexes and that the changes in the 305 ps component are due to aggregated light-harvesting complex II trimers that have detached from PSII. We anticipate that this technique will be useful for resolving the various mechanisms of NPQ and for quantifying the timescales associated with these mechanisms.
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Tsiavos T, Ioannidis NE, Kotzabasis K. Polyamines induce aggregation of LHC II and quenching of fluorescence in vitro. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1817:735-43. [PMID: 22285699 DOI: 10.1016/j.bbabio.2012.01.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 12/25/2011] [Accepted: 01/13/2012] [Indexed: 10/14/2022]
Abstract
Dissipation of excess excitation energy within the light-harvesting complex of Photosystem II (LHC II) is a main process in plants, which is measured as the non-photochemical quenching of chlorophyll fluorescence or qE. We showed in previous works that polyamines stimulate qE in higher plants in vivo and in eukaryotic algae in vitro. In the present contribution we have tested whether polyamines can stimulate quenching in trimeric LHC II and monomeric light-harvesting complex b proteins from higher plants. The tetramine spermine was the most potent quencher and induced aggregation of LHC II trimers, due to its highly cationic character. Two transients are evident at 100 μM and 350 μM for the fluorescence and absorbance signals of LHC II respectively. On the basis of observations within this work, some links between polyamines and the activation of qE in vivo is discussed.
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Affiliation(s)
- Theodoros Tsiavos
- Department of Biology, University of Crete, P.O. Box 2208, GR-71409 Heraklion, Crete, Greece
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Schmitz J, Schöttler MA, Krueger S, Geimer S, Schneider A, Kleine T, Leister D, Bell K, Flügge UI, Häusler RE. Defects in leaf carbohydrate metabolism compromise acclimation to high light and lead to a high chlorophyll fluorescence phenotype in Arabidopsis thaliana. BMC PLANT BIOLOGY 2012; 12:8. [PMID: 22248311 PMCID: PMC3353854 DOI: 10.1186/1471-2229-12-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 01/16/2012] [Indexed: 05/18/2023]
Abstract
BACKGROUND We have studied the impact of carbohydrate-starvation on the acclimation response to high light using Arabidopsis thaliana double mutants strongly impaired in the day- and night path of photoassimilate export from the chloroplast. A complete knock-out mutant of the triose phosphate/phosphate translocator (TPT; tpt-2 mutant) was crossed to mutants defective in (i) starch biosynthesis (adg1-1, pgm1 and pgi1-1; knock-outs of ADP-glucose pyrophosphorylase, plastidial phosphoglucomutase and phosphoglucose isomerase) or (ii) starch mobilization (sex1-3, knock-out of glucan water dikinase) as well as in (iii) maltose export from the chloroplast (mex1-2). RESULTS All double mutants were viable and indistinguishable from the wild type when grown under low light conditions, but--except for sex1-3/tpt-2--developed a high chlorophyll fluorescence (HCF) phenotype and growth retardation when grown in high light. Immunoblots of thylakoid proteins, Blue-Native gel electrophoresis and chlorophyll fluorescence emission analyses at 77 Kelvin with the adg1-1/tpt-2 double mutant revealed that HCF was linked to a specific decrease in plastome-encoded core proteins of both photosystems (with the exception of the PSII component cytochrome b559), whereas nuclear-encoded antennae (LHCs) accumulated normally, but were predominantly not attached to their photosystems. Uncoupled antennae are the major cause for HCF of dark-adapted plants. Feeding of sucrose or glucose to high light-grown adg1-1/tpt-2 plants rescued the HCF- and growth phenotypes. Elevated sugar levels induce the expression of the glucose-6-phosphate/phosphate translocator2 (GPT2), which in principle could compensate for the deficiency in the TPT. A triple mutant with an additional defect in GPT2 (adg1-1/tpt-2/gpt2-1) exhibited an identical rescue of the HCF- and growth phenotype in response to sugar feeding as the adg1-1/tpt-2 double mutant, indicating that this rescue is independent from the sugar-triggered induction of GPT2. CONCLUSIONS We propose that cytosolic carbohydrate availability modulates acclimation to high light in A. thaliana. It is conceivable that the strong relationship between the chloroplast and nucleus with respect to a co-ordinated expression of photosynthesis genes is modified in carbohydrate-starved plants. Hence carbohydrates may be considered as a novel component involved in chloroplast-to-nucleus retrograde signaling, an aspect that will be addressed in future studies.
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Affiliation(s)
- Jessica Schmitz
- University of Cologne, Botanical Institute, Biocenter Cologne, Zülpicher Str. 47B, D-50674 Cologne, Germany
| | - Mark Aurel Schöttler
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Stephan Krueger
- University of Cologne, Botanical Institute, Biocenter Cologne, Zülpicher Str. 47B, D-50674 Cologne, Germany
| | - Stefan Geimer
- Universität Bayreuth, Zellbiologie/Elektronenmikroskopie NW I/B1, Universitätsstrasse 30, D-95447 Bayreuth, Germany
| | - Anja Schneider
- Biozentrum der Ludwig-Maximilians-Universität München, Department Biologie I - Botanik Großhaderner Str. 2-4, D-82152 Planegg-Martinsried, Germany
| | - Tatjana Kleine
- Biozentrum der Ludwig-Maximilians-Universität München, Department Biologie I - Botanik Großhaderner Str. 2-4, D-82152 Planegg-Martinsried, Germany
| | - Dario Leister
- Biozentrum der Ludwig-Maximilians-Universität München, Department Biologie I - Botanik Großhaderner Str. 2-4, D-82152 Planegg-Martinsried, Germany
| | - Kirsten Bell
- University of Cologne, Botanical Institute, Biocenter Cologne, Zülpicher Str. 47B, D-50674 Cologne, Germany
| | - Ulf-Ingo Flügge
- University of Cologne, Botanical Institute, Biocenter Cologne, Zülpicher Str. 47B, D-50674 Cologne, Germany
| | - Rainer E Häusler
- University of Cologne, Botanical Institute, Biocenter Cologne, Zülpicher Str. 47B, D-50674 Cologne, Germany
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Jajoo A, Szabó M, Zsiros O, Garab G. Low pH induced structural reorganization in thylakoid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1388-91. [PMID: 22248669 DOI: 10.1016/j.bbabio.2012.01.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 12/22/2011] [Accepted: 01/02/2012] [Indexed: 11/19/2022]
Abstract
By using low temperature fluorescence spectroscopy, it has been shown that exposing chloroplast thylakoid membranes to acidic pH reversibly decreases the fluorescence of photosystem II while the fluorescence of photosystem I increases [P. Singh-Rawal et al. (2010) Evidence that pH can drive state transitions in isolated thylakoid membranes from spinach, Photochem Photobiol Sci, 9 830-837]. In order to shed light on the origin of these changes, we performed circular dichroism (CD) spectroscopy on freshly isolated pea thylakoid membranes. We show that the magnitude of the psi-type CD, which is associated with the presence of chirally ordered macroarrays of the chromophores in intact thylakoid membranes, decreases gradually and reversibly upon gradually lowering the pH of the medium from 7.5 to 4.5 (psi, polymer or salt induced). The same treatment, as shown on thylakoid membranes washed in hypotonic low salt medium possessing no psi-type bands, induces no discernible change in the excitonic CD. These data show that while no change in the pigment-pigment interactions and thus in the molecular organization of the bulk protein complexes can be held responsible for the observed changes in the fluorescence, acidification of the medium significantly alters the macro-organization of the complexes, hence providing an explanation for the pH-induced redistribution of the excitation energy between the two photosystems. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
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Affiliation(s)
- Anjana Jajoo
- School of Life Science, Devi Ahilya University, Indore, India.
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Pandit A, Shirzad-Wasei N, Wlodarczyk LM, van Roon H, Boekema EJ, Dekker JP, de Grip WJ. Assembly of the major light-harvesting complex II in lipid nanodiscs. Biophys J 2011; 101:2507-15. [PMID: 22098750 DOI: 10.1016/j.bpj.2011.09.055] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 09/20/2011] [Accepted: 09/27/2011] [Indexed: 11/15/2022] Open
Abstract
Self-aggregation of isolated plant light-harvesting complexes (LHCs) upon detergent extraction is associated with fluorescence quenching and is used as an in vitro model to study the photophysical processes of nonphotochemical quenching (NPQ). In the NPQ state, in vivo induced under excess solar light conditions, harmful excitation energy is safely dissipated as heat. To prevent self-aggregation and probe the conformations of LHCs in a lipid environment devoid from detergent interactions, we assembled LHCII trimer complexes into lipid nanodiscs consisting of a bilayer lipid matrix surrounded by a membrane scaffold protein (MSP). The LHCII nanodiscs were characterized by fluorescence spectroscopy and found to be in an unquenched, fluorescent state. Remarkably, the absorbance spectra of LHCII in lipid nanodiscs show fine structure in the carotenoid and Q(y) region that is different from unquenched, detergent-solubilized LHCII but similar to that of self-aggregated, quenched LHCII in low-detergent buffer without magnesium ions. The nanodisc data presented here suggest that 1), LHCII pigment-protein complexes undergo conformational changes upon assembly in nanodiscs that are not correlated with downregulation of its light-harvesting function; and 2), these effects can be separated from quenching and aggregation-related phenomena. This will expand our present view of the conformational flexibility of LHCII in different microenvironments.
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Affiliation(s)
- Anjali Pandit
- Section of Biophysics, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands.
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Porcar-Castell A. A high-resolution portrait of the annual dynamics of photochemical and non-photochemical quenching in needles of Pinus sylvestris. PHYSIOLOGIA PLANTARUM 2011; 143:139-53. [PMID: 21615415 DOI: 10.1111/j.1399-3054.2011.01488.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Partitioning of excitation energy between photochemical quenching (PQ) and non-photochemical quenching (NPQ) processes is constantly adjusted in the leaf in order to preserve the photosynthetic energy balance. Adjustments in PQ and NPQ often result from a combination of different temporal components that can be simplified into reversible and sustained components. While reversible PQ and NPQ are relatively well understood, the controls behind the sustained components of PQ and NPQ, or the interaction between sustained and reversible NPQ, remain elusive. In this study, I used a full year of high-resolution chlorophyll fluorescence (ChlF) data obtained with a Monitoring-PAM fluorometer (Walz, Effeltrich, Germany) in needles of boreal Pinus sylvestris in situ to quantitatively analyse the dynamics and interaction between temporal components of NPQ and PQ and their control by the environment. To enable the estimation of sustained and reversible components of PQ and NPQ, a number of key ChlF parameters were reviewed and adapted to the analysis of long-term monitoring data. Overall, NPQ was drastically enhanced during winter via the accumulation of sustained NPQ in a process regulated by air temperature. Reversible NPQ retained some functionality even at temperatures well below zero and was not inhibited by the presence of sustained NPQ per se but by low temperatures alone. This suggests that temporal NPQ components co-operate in an additive rather than complementary fashion, conferring additional flexibility to the photoprotective role of NPQ. Finally, the potential of the sustained photochemical quenching parameter (qL(s) ) to track photoinhibition in situ was discussed.
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Affiliation(s)
- Albert Porcar-Castell
- Department of Forest Sciences, University of Helsinki, PO Box 27, 00014 Helsinki, Finland.
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van Oort B, Maréchal A, Ruban AV, Robert B, Pascal AA, de Ruijter NCA, van Grondelle R, van Amerongen H. Different crystal morphologies lead to slightly different conformations of light-harvesting complex II as monitored by variations of the intrinsic fluorescence lifetime. Phys Chem Chem Phys 2011; 13:12614-22. [PMID: 21670839 DOI: 10.1039/c1cp20331b] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In 2005, it was found that the fluorescence of crystals of the major light-harvesting complex LHCII of green plants is significantly quenched when compared to the fluorescence of isolated LHCII (A. A. Pascal et al., Nature, 2005, 436, 134-137). The Raman spectrum of crystallized LHCII was also found to be different from that of isolated LHCII but very similar to that of aggregated LHCII, which has often been considered a good model system for studying nonphotochemical quenching (NPQ), the major protection mechanism of plants against photodamage in high light. It was proposed that in the crystal LHCII adopts a similar (quenching) conformation as during NPQ and indeed similar changes in the Raman spectrum were observed during NPQ in vivo (A. V. Ruban et al., Nature, 2007, 450, 575-579). We now compared the fluorescence of various types of crystals, differing in morphology and age. Each type gave rise to its own characteristic mono-exponential fluorescence lifetime, which was 5 to 10 times shorter than that of isolated LHCII. This indicates that fluorescence is not quenched by random impurities and packing defects (as proposed recently by T. Barros et al., EMBO Journal, 2009, 28, 298-306), but that LHCII adopts a particular structure in each crystal type, that leads to fluorescence quenching. Most interestingly, the extent of quenching appears to depend on the crystal morphology, indicating that also the crystal structure depends on this crystal morphology but at the moment no data are available to correlate the crystals' structural changes to changes in fluorescence lifetime.
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Affiliation(s)
- Bart van Oort
- VU University Amsterdam, Faculty of Sciences, Department of Physics and Astronomy, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
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Zia A, Johnson MP, Ruban AV. Acclimation- and mutation-induced enhancement of PsbS levels affects the kinetics of non-photochemical quenching in Arabidopsis thaliana. PLANTA 2011; 233:1253-1264. [PMID: 21340700 DOI: 10.1007/s00425-011-1380-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Accepted: 02/07/2011] [Indexed: 05/30/2023]
Abstract
The efficiency of photosystem II antenna complexes (LHCs) in higher plants must be regulated to avoid potentially damaging overexcitation of the reaction centre in excess light. Regulation is achieved via a feedback mechanism known as non-photochemical quenching (NPQ), triggered the proton gradient (ΔpH) causing heat dissipation within the LHC antenna. ΔpH causes protonation of the LHCs, the PsbS protein and triggers the enzymatic de-epoxidation of the xanthophyll, violaxanthin, to zeaxanthin. A key step in understanding the mechanism is to decipher whether PsbS and zeaxanthin cooperate to promote NPQ. To obtain clues about their respective functions we studied the effects of PsbS and zeaxanthin on the rates of NPQ formation and relaxation in wild-type Arabidopsis leaves and those overexpressing PsbS (L17) or lacking zeaxanthin (npq1). Overexpression of PsbS was found to increase the rate of NPQ formation, as previously reported for zeaxanthin. However, PsbS overexpression also increased the rate of NPQ relaxation, unlike zeaxanthin, which is known decrease the rate. The enhancement of PsbS levels in plants lacking zeaxanthin (npq1) by either acclimation to high light or crossing with L17 plants showed that the effect of PsbS was independent of zeaxanthin. PsbS levels also affected the kinetics of the 535 nm absorption change (ΔA535), which monitors the formation of the conformational state of the LHC antenna associated with NPQ, in an identical way. The antagonistic action of PsbS and zeaxanthin with respect to NPQ and ΔA535 relaxation kinetics suggests that the two molecules have distinct regulatory functions.
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Affiliation(s)
- Ahmad Zia
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End, Bancroft Road, Fogg Building, London E14NS, UK
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Ruban AV, Johnson MP, Duffy CDP. The photoprotective molecular switch in the photosystem II antenna. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1817:167-81. [PMID: 21569757 DOI: 10.1016/j.bbabio.2011.04.007] [Citation(s) in RCA: 493] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 03/28/2011] [Accepted: 04/01/2011] [Indexed: 10/18/2022]
Abstract
We have reviewed the current state of multidisciplinary knowledge of the photoprotective mechanism in the photosystem II antenna underlying non-photochemical chlorophyll fluorescence quenching (NPQ). The physiological need for photoprotection of photosystem II and the concept of feed-back control of excess light energy are described. The outline of the major component of nonphotochemical quenching, qE, is suggested to comprise four key elements: trigger (ΔpH), site (antenna), mechanics (antenna dynamics) and quencher(s). The current understanding of the identity and role of these qE components is presented. Existing opinions on the involvement of protons, different LHCII antenna complexes, the PsbS protein and different xanthophylls are reviewed. The evidence for LHCII aggregation and macrostructural reorganization of photosystem II and their role in qE are also discussed. The models describing the qE locus in LHCII complexes, the pigments involved and the evidence for structural dynamics within single monomeric antenna complexes are reviewed. We suggest how PsbS and xanthophylls may exert control over qE by controlling the affinity of LHCII complexes for protons with reference to the concepts of hydrophobicity, allostery and hysteresis. Finally, the physics of the proposed chlorophyll-chlorophyll and chlorophyll-xanthophyll mechanisms of energy quenching is explained and discussed. This article is part of a Special Issue entitled: Photosystem II.
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Affiliation(s)
- Alexander V Ruban
- Queen Mary Universityof London, School of Biological & Chemical Sciences, Mile Enf Road, London E1 4TN, UK.
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Johnson MP, Goral TK, Duffy CD, Brain AP, Mullineaux CW, Ruban AV. Photoprotective energy dissipation involves the reorganization of photosystem II light-harvesting complexes in the grana membranes of spinach chloroplasts. THE PLANT CELL 2011; 23:1468-79. [PMID: 21498680 PMCID: PMC3101555 DOI: 10.1105/tpc.110.081646] [Citation(s) in RCA: 253] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 03/08/2011] [Accepted: 03/28/2011] [Indexed: 05/18/2023]
Abstract
Plants must regulate their use of absorbed light energy on a minute-by-minute basis to maximize the efficiency of photosynthesis and to protect photosystem II (PSII) reaction centers from photooxidative damage. The regulation of light harvesting involves the photoprotective dissipation of excess absorbed light energy in the light-harvesting antenna complexes (LHCs) as heat. Here, we report an investigation into the structural basis of light-harvesting regulation in intact spinach (Spinacia oleracea) chloroplasts using freeze-fracture electron microscopy, combined with laser confocal microscopy employing the fluorescence recovery after photobleaching technique. The results demonstrate that formation of the photoprotective state requires a structural reorganization of the photosynthetic membrane involving dissociation of LHCII from PSII and its aggregation. The structural changes are manifested by a reduced mobility of LHC antenna chlorophyll proteins. It is demonstrated that these changes occur rapidly and reversibly within 5 min of illumination and dark relaxation, are dependent on ΔpH, and are enhanced by the deepoxidation of violaxanthin to zeaxanthin.
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Affiliation(s)
- Matthew P. Johnson
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Tomasz K. Goral
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Christopher D.P. Duffy
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Anthony P.R. Brain
- Centre for Ultrastructural Imaging, Kings College University of London, London SE1 1UL, United Kingdom
| | - Conrad W. Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Alexander V. Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
- Address correspondence to
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Vladkova R, Dobrikova AG, Singh R, Misra AN, Apostolova E. Photoelectron transport ability of chloroplast thylakoid membranes treated with NO donor SNP: changes in flash oxygen evolution and chlorophyll fluorescence. Nitric Oxide 2011; 24:84-90. [PMID: 21167290 DOI: 10.1016/j.niox.2010.12.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Revised: 11/11/2010] [Accepted: 12/12/2010] [Indexed: 01/06/2023]
Abstract
The nitric oxide (NO) donor sodium nitroprusside (SNP) is frequently used in plant science in vivo. The present in vitro study reveals its effects on the photosynthetic oxygen evolution and the chlorophyll fluorescence directly on isolated pea thylakoid membranes. It was found that even at very low amounts of SNP (chlorophyll/SNP molar ratio∼67:1), the SNP-donated NO stimulates with more than 50% the overall photosystem II electron transport rate and diminishes the evolution of molecular oxygen. It was also found that the target site for SNP-donated NO is the donor side of photosystem II. Compared with other NO-donors used in plant science, SNP seems to be the only one exhibiting stimulation of electron transport through photosystem II.
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Affiliation(s)
- Radka Vladkova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Science, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria
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Wright AH, DeLong JM, Gunawardena AHLAN, Prange RK. The interrelationship between the lower oxygen limit, chlorophyll fluorescence and the xanthophyll cycle in plants. PHOTOSYNTHESIS RESEARCH 2011; 107:223-35. [PMID: 21290261 DOI: 10.1007/s11120-011-9621-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Accepted: 01/03/2011] [Indexed: 05/07/2023]
Abstract
The lower oxygen limit (LOL) in plants may be identified through the measure of respiratory gases [i.e. the anaerobic compensation point (ACP) or the respiratory quotient breakpoint (RQB)], but recent work shows it may also be identified by a sudden rise in dark minimum fluorescence (F(o)). The interrelationship between aerobic respiration and fermentative metabolism, which occur in the mitochondria and cytosol, respectively, and fluorescence, which emanates from the chloroplasts, is not well documented in the literature. Using spinach (Spinacia oleracea), this study showed that F(o) and photochemical quenching (q(P)) remained relatively unchanged until O(2) levels dropped below the LOL. An over-reduction of the plastoquinone (PQ) pool is believed to increase F(o) under dark + anoxic conditions. It is proposed that excess cytosolic reductant due to inhibition of the mitochondria's cytochrome oxidase under low-O(2), may be the primary reductant source. The maximum fluorescence (F(m)) is largely unaffected by low-O(2) in the dark, but was severely quenched, mirroring changes to the xanthophyll de-epoxidation state (DEPS), under even low-intensity light (≈4 μmol m(-2) s(-1)). In low light, the low-O(2)-induced increase in F(o) was also quenched, likely by non-photochemical and photochemical means. The degree of quenching in the light was negatively correlated with the level of ethanol fermentation in the dark. A discussion detailing the possible roles of cyclic electron flow, the xanthophyll cycle, chlororespiration and a pathway we termed 'chlorofermentation' were used to interpret fluorescence phenomena of both spinach and apple (Malus domestica) over a range of atmospheric conditions under both dark and low-light.
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Affiliation(s)
- A Harrison Wright
- Atlantic Food and Horticulture Research Centre, Agriculture and Agri-Food Canada, Kentville, NS, Canada.
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Photosystem II fluorescence lifetime imaging in avocado leaves: contributions of the lutein-epoxide and violaxanthin cycles to fluorescence quenching. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2011; 104:271-84. [PMID: 21356597 DOI: 10.1016/j.jphotobiol.2011.01.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 01/03/2011] [Accepted: 01/05/2011] [Indexed: 11/23/2022]
Abstract
Lifetime-resolved imaging measurements of chlorophyll a fluorescence were made on leaves of avocado plants to study whether rapidly reversible ΔpH-dependent (transthylakoid H(+) concentration gradient) thermal energy dissipation (qE) and slowly reversible ΔpH-independent fluorescence quenching (qI) are modulated by lutein-epoxide and violaxanthin cycles operating in parallel. Under normal conditions (without inhibitors), analysis of the chlorophyll a fluorescence lifetime data revealed two major lifetime pools (1.5 and 0.5 ns) for photosystem II during the ΔpH build-up under illumination. Formation of the 0.5-ns pool upon illumination was correlated with dark-retention of antheraxanthin and photo-converted lutein in leaves. Interconversion between the 1.5- and 0.5-ns lifetime pools took place during the slow part of the chlorophyll a fluorescence transient: first from 1.5 ns to 0.5 ns in the P-to-S phase, then back from 0.5 ns to 1.5 ns in the S-to-M phase. When linear electron transport and the resulting ΔpH build-up were inhibited by treatment with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), the major fluorescence intensity was due to a 2.2-ns lifetime pool with a minor faster contribution of approximately 0.7 ns. In the presence of DCMU, neither the intensity nor the lifetimes of fluorescence were affected by antheraxanthin and photo-converted lutein. Thus, we conclude that both antheraxanthin and photo-converted lutein are able to enhance ΔpH-dependent qE processes that are associated with the 0.5-ns lifetime pool. However, unlike zeaxanthin, retention of antheraxanthin and photo-converted lutein may not by itself stabilize quenching or cause qI.
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Ilioaia C, Johnson MP, Duffy CDP, Pascal AA, van Grondelle R, Robert B, Ruban AV. Origin of absorption changes associated with photoprotective energy dissipation in the absence of zeaxanthin. J Biol Chem 2010; 286:91-8. [PMID: 21036900 DOI: 10.1074/jbc.m110.184887] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To prevent photo-oxidative damage to the photosynthetic membrane in strong light, plants dissipate excess absorbed light energy as heat in a mechanism known as non-photochemical quenching (NPQ). NPQ is triggered by the trans-membrane proton gradient (ΔpH), which causes the protonation of the photosystem II light-harvesting antenna (LHCII) and the PsbS protein, as well as the de-epoxidation of the xanthophyll violaxanthin to zeaxanthin. The combination of these factors brings about formation of dissipative pigment interactions that quench the excess energy. The formation of NPQ is associated with certain absorption changes that have been suggested to reflect a conformational change in LHCII brought about by its protonation. The light-minus-dark recovery absorption difference spectrum is characterized by a series of positive and negative bands, the best known of which is ΔA(535). Light-minus-dark recovery resonance Raman difference spectra performed at the wavelength of the absorption change of interest allows identification of the pigment responsible from its unique vibrational signature. Using this technique, the origin of ΔA(535) was previously shown to be a subpopulation of red-shifted zeaxanthin molecules. In the absence of zeaxanthin (and antheraxanthin), a proportion of NPQ remains, and the ΔA(535) change is blue-shifted to 525 nm (ΔA(525)). Using resonance Raman spectroscopy, it is shown that the ΔA(525) absorption change in Arabidopsis leaves lacking zeaxanthin belongs to a red-shifted subpopulation of violaxanthin molecules formed during NPQ. The presence of the same ΔA(535) and ΔA(525) Raman signatures in vitro in aggregated LHCII, containing zeaxanthin and violaxanthin, respectively, leads to a new proposal for the origin of the xanthophyll red shifts associated with NPQ.
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Affiliation(s)
- Cristian Ilioaia
- Commisariat à l'Energie Atomique, Institut de Biologie et Technologies de Saclay (iBiTecS), CNRS Unité de Recherche Associée 2096, Gif sur Yvette, F-91191 France.
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Niedzwiedzki DM, Enriquez MM, LaFountain AM, Frank HA. Ultrafast Time-resolved Absorption Spectroscopy of Geometric Isomers of Xanthophylls. Chem Phys 2010; 373:80-89. [PMID: 20689726 PMCID: PMC2913875 DOI: 10.1016/j.chemphys.2010.01.019] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This paper presents an ultrafast optical spectroscopic investigation of the excited state energies, lifetimes and spectra of specific geometric isomers of neoxanthin, violaxanthin, lutein, and zeaxanthin. All-trans- and 15,15'-cis-beta-carotene were also examined. The spectroscopy was done on molecules purified by HPLC frozen immediately to inhibit isomerization. The spectra were taken at 77 K to maintain the configurations and to provide better spectral resolution than seen at room temperature. The kinetics reveal that for all of the molecules except neoxanthin, the S(1) state lifetime of the cis-isomers is shorter than that of the all-trans isomers. The S(1) excited state energies of all the isomers were determined by recording S(1) --> S(2) transient absorption spectra. The results obtained in this manner at cryogenic temperatures provide an unprecedented level of precision in the measurement of the S(1) energies of these xanthophylls, which are critical components in light-harvesting pigment-protein complexes of green plants.
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Affiliation(s)
| | - Miriam M. Enriquez
- Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060, USA
| | - Amy M. LaFountain
- Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060, USA
| | - Harry A. Frank
- Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060, USA
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Effect of xanthophyll composition on the chlorophyll excited state lifetime in plant leaves and isolated LHCII. Chem Phys 2010. [DOI: 10.1016/j.chemphys.2009.12.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Liao PN, Bode S, Wilk L, Hafi N, Walla PJ. Correlation of electronic carotenoid–chlorophyll interactions and fluorescence quenching with the aggregation of native LHC II and chlorophyll deficient mutants. Chem Phys 2010. [DOI: 10.1016/j.chemphys.2010.01.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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