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Patil PP, Mohammad Aslam S, Vass I, Szabó M. Characterization of the wave phenomenon of flash-induced chlorophyll fluorescence in Chlamydomonas reinhardtii. Photosynth Res 2022; 152:235-244. [PMID: 35166999 PMCID: PMC9424139 DOI: 10.1007/s11120-022-00900-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 01/25/2022] [Indexed: 06/01/2023]
Abstract
Flash-induced chlorophyll fluorescence relaxation is a powerful tool to monitor the reoxidation reactions of the reduced primary quinone acceptor, QA- by QB and the plastoquinone (PQ) pool, as well as the charge recombination reactions between the donor and acceptor side components of Photosystem II (PSII). Under certain conditions, when the PQ pool is highly reduced (e.g. in microaerobic conditions), a wave phenomenon appears in the fluorescence relaxation kinetics, which reflects the transient reoxidation and re-reduction of QA- by various electron transfer processes, which in cyanobacteria is mediated by NAD(P)H dehydrogenase (NDH-1). The wave phenomenon was also observed and assigned to the operation of type 2 NAD(P)H dehydrogenase (NDH-2) in the green alga Chlamydomonas reinhardtii under hydrogen-producing conditions, which required a long incubation of algae under sulphur deprivation (Krishna et al. J Exp Bot 70 (21):6321-6336, 2019). However, the conditions that induce the wave remained largely uncharacterized so far in microalgae. In this work, we investigated the wave phenomenon in Chlamydomonas reinhardtii under conditions that lead to a decrease of PSII activity by applying hydroxylamine treatment, which impacts the donor side of PSII in combination with a strongly reducing environment of the PQ pool (microaerobic conditions). A similar wave phenomenon could be induced by photoinhibitory conditions (illumination with strong light in the presence of the protein synthesis inhibitor lincomycin). These results indicate that the fluorescence wave phenomenon is activated in green algae when the PSII activity decreases relative to Photosystem I (PS I) activity and the PQ pool is strongly reduced. Therefore, the fluorescence wave could be used as a sensitive indicator of altered intersystem electron transfer processes, e.g. under stress conditions.
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Affiliation(s)
- Priyanka Pradeep Patil
- Biological Research Centre, Institute of Plant Biology, Eötvös Loránd Research Network (ELKH), Szeged, Hungary
| | - Sabit Mohammad Aslam
- Biological Research Centre, Institute of Plant Biology, Eötvös Loránd Research Network (ELKH), Szeged, Hungary
- Doctoral School of Biology, University of Szeged, Szeged, Hungary
| | - Imre Vass
- Biological Research Centre, Institute of Plant Biology, Eötvös Loránd Research Network (ELKH), Szeged, Hungary.
| | - Milán Szabó
- Biological Research Centre, Institute of Plant Biology, Eötvös Loránd Research Network (ELKH), Szeged, Hungary.
- Climate Change Cluster, University of Technology Sydney, Ultimo, Australia.
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Solymosi D, Shevela D, Allahverdiyeva Y. Nitric oxide represses photosystem II and NDH-1 in the cyanobacterium Synechocystis sp. PCC 6803. Biochim Biophys Acta Bioenerg 2022; 1863:148507. [PMID: 34728155 DOI: 10.1016/j.bbabio.2021.148507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 10/20/2021] [Accepted: 10/27/2021] [Indexed: 11/16/2022]
Abstract
Photosynthetic electron transfer comprises a series of light-induced redox reactions catalysed by multiprotein machinery in the thylakoid. These protein complexes possess cofactors susceptible to redox modifications by reactive small molecules. The gaseous radical nitric oxide (NO), a key signalling molecule in green algae and plants, has earlier been shown to bind to Photosystem (PS) II and obstruct electron transfer in plants. The effects of NO on cyanobacterial bioenergetics however, have long remained obscure. In this study, we exposed the model cyanobacterium Synechocystis sp. PCC 6803 to NO under anoxic conditions and followed changes in whole-cell fluorescence and oxidoreduction of P700 in vivo. Our results demonstrate that NO blocks photosynthetic electron transfer in cells by repressing PSII, PSI, and likely the NDH dehydrogenase-like complex 1 (NDH-1). We propose that iron‑sulfur clusters of NDH-1 complex may be affected by NO to such an extent that ferredoxin-derived electron injection to the plastoquinone pool, and thus cyclic electron transfer, may be inhibited. These findings reveal the profound effects of NO on Synechocystis cells and demonstrate the importance of controlled NO homeostasis in cyanobacteria.
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Affiliation(s)
- Daniel Solymosi
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, FI 20014, Finland
| | - Dmitry Shevela
- Chemical Biological Centre, Department of Chemistry, Umeå University, 90187 Umeå, Sweden
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, FI 20014, Finland.
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Theune ML, Hildebrandt S, Steffen-Heins A, Bilger W, Gutekunst K, Appel J. In-vivo quantification of electron flow through photosystem I - Cyclic electron transport makes up about 35% in a cyanobacterium. Biochim Biophys Acta Bioenerg 2020; 1862:148353. [PMID: 33346012 DOI: 10.1016/j.bbabio.2020.148353] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/23/2020] [Accepted: 12/08/2020] [Indexed: 12/15/2022]
Abstract
Photosynthetic electron flow, driven by photosystem I and II, provides chemical energy for carbon fixation. In addition to a linear mode a second cyclic route exists, which only involves photosystem I. The exact contributions of linear and cyclic transport are still a matter of debate. Here, we describe the development of a method that allows quantification of electron flow in absolute terms through photosystem I in a photosynthetic organism for the first time. Specific in-vivo protocols allowed to discern the redox states of plastocyanin, P700 and the FeS-clusters including ferredoxin at the acceptor site of PSI in the cyanobacterium Synechocystis sp. PCC 6803 with the near-infrared spectrometer Dual-KLAS/NIR. P700 absorbance changes determined with the Dual-KLAS/NIR correlated linearly with direct determinations of PSI concentrations using EPR. Dark-interval relaxation kinetics measurements (DIRKPSI) were applied to determine electron flow through PSI. Counting electrons from hydrogen oxidation as electron donor to photosystem I in parallel to DIRKPSI measurements confirmed the validity of the method. Electron flow determination by classical PSI yield measurements overestimates electron flow at low light intensities and saturates earlier compared to DIRKPSI. Combination of DIRKPSI with oxygen evolution measurements yielded a proportion of 35% of surplus electrons passing PSI compared to PSII. We attribute these electrons to cyclic electron transport, which is twice as high as assumed for plants. Counting electrons flowing through the photosystems allowed determination of the number of quanta required for photosynthesis to 11 per oxygen produced, which is close to published values.
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Affiliation(s)
- Marius L Theune
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Sarah Hildebrandt
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Anja Steffen-Heins
- Division of Food Technology, Institute of Human Nutrition and Food Science, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Wolfgang Bilger
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Kirstin Gutekunst
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Jens Appel
- Department of Biology, Botanical Institute, Christian-Albrechts-University, 24118 Kiel, Germany.
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Zhang MM, Fan DY, Murakami K, Badger MR, Sun GY, Chow WS. Partially Dissecting Electron Fluxes in Both Photosystems in Spinach Leaf Disks during Photosynthetic Induction. Plant Cell Physiol 2019; 60:2206-2219. [PMID: 31271439 DOI: 10.1093/pcp/pcz114] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Accepted: 05/29/2019] [Indexed: 06/09/2023]
Abstract
Photosynthetic induction, a gradual increase in photosynthetic rate on a transition from darkness or low light to high light, has ecological significance, impact on biomass accumulation in fluctuating light and relevance to photoprotection in strong light. However, the experimental quantification of the component electron fluxes in and around both photosystems during induction has been rare. Combining optimized chlorophyll fluorescence, the redox kinetics of P700 [primary electron donor in Photosystem I (PSI)] and membrane inlet mass spectrometry in the absence/presence of inhibitors/mediator, we partially estimated the components of electron fluxes in spinach leaf disks on transition from darkness to 1,000 �mol photons�m-2�s-1 for up to 10 min, obtaining the following findings: (i) the partitioning of energy between both photosystems did not change noticeably; (ii) in Photosystem II (PSII), the combined cyclic electron flow (CEF2) and charge recombination (CR2) to the ground state decreased gradually toward 0 in steady state; (iii) oxygen reduction by electrons from PSII, partly bypassing PSI, was small but measurable; (iv) cyclic electron flow around PSI (CEF1) peaked before becoming somewhat steady; (v) peak magnitudes of some of the electron fluxes, all probably photoprotective, were in the descending order: CEF1 > CEF2 + CR2 > chloroplast O2 uptake; and (vi) the chloroplast NADH dehydrogenase-like complex appeared to aid the antimycin A-sensitive CEF1. The results are important for fine-tuning in silico simulation of in vivo photosynthetic electron transport processes; such simulation is, in turn, necessary to probe partial processes in a complex network of interactions in response to environmental changes.
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Affiliation(s)
- Meng-Meng Zhang
- Department of Plant Physiology, College of Life Science, Northeast Forestry University, Harbin, Heilongjiang, China
- Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - Da-Yong Fan
- Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, Australia
- College of Forestry, Beijing Forestry University, Beijing, China
| | - Keach Murakami
- Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, Australia
- National Agriculture and Food Research Organization (NARO), Hokkaido Agricultural Research Center (HARC), Hitsujigaoka 1, Toyohira, Sapporo, Japan
| | - Murray R Badger
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - Guang-Yu Sun
- Department of Plant Physiology, College of Life Science, Northeast Forestry University, Harbin, Heilongjiang, China
| | - Wah Soon Chow
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Acton, ACT, Australia
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Deák Z, Sass L, Kiss E, Vass I. Characterization of wave phenomena in the relaxation of flash-induced chlorophyll fluorescence yield in cyanobacteria. Biochim Biophys Acta 2014; 1837:1522-32. [PMID: 24434028 DOI: 10.1016/j.bbabio.2014.01.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 12/30/2013] [Accepted: 01/07/2014] [Indexed: 12/25/2022]
Abstract
Fluorescence yield relaxation following a light pulse was studied in various cyanobacteria under aerobic and microaerobic conditions. In Synechocystis PCC 6803 fluorescence yield decays in a monotonous fashion under aerobic conditions. However, under microaerobic conditions the decay exhibits a wave feature showing a dip at 30-50 ms after the flash followed by a transient rise, reaching maximum at ~1s, before decaying back to the initial level. The wave phenomenon can also be observed under aerobic conditions in cells preilluminated with continuous light. Illumination preconditions cells for the wave phenomenon transiently: for few seconds in Synechocystis PCC 6803, but up to one hour in Thermosynechocystis elongatus BP-1. The wave is eliminated by inhibition of plastoquinone binding either to the QB site of Photosystem-II or the Qo site of cytochrome b6f complex by 3-(3',4'-dichlorophenyl)-1,1-dimethylurea or 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone, respectively. The wave is also absent in mutants, which lack either Photosystem-I or the NAD(P)H-quinone oxidoreductase (NDH-1) complex. Monitoring the redox state of the plastoquinone pool revealed that the dip of the fluorescence wave corresponds to transient oxidation, whereas the following rise to re-reduction of the plastoquinone pool. It is concluded that the unusual wave feature of fluorescence yield relaxation reflects transient oxidation of highly reduced plastoquinone pool by Photosystem-I followed by its re-reduction from stromal components via the NDH-1 complex, which is transmitted back to the fluorescence yield modulator primary quinone electron acceptor via charge equilibria. Potential applications of the wave phenomenon in studying photosynthetic and respiratory electron transport are discussed. This article is part of a special issue entitled: photosynthesis research for sustainability: keys to produce clean energy.
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Affiliation(s)
- Zsuzsanna Deák
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, Temesvari krt. 62, 6726 Szeged, Hungary
| | - László Sass
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, Temesvari krt. 62, 6726 Szeged, Hungary
| | - Eva Kiss
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, Temesvari krt. 62, 6726 Szeged, Hungary
| | - Imre Vass
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, Temesvari krt. 62, 6726 Szeged, Hungary.
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