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Bernát G, Steinbach G, Kaňa R, Misra AN, Prašil O. On the origin of the slow M-T chlorophyll a fluorescence decline in cyanobacteria: interplay of short-term light-responses. PHOTOSYNTHESIS RESEARCH 2018; 136:183-198. [PMID: 29090427 DOI: 10.1007/s11120-017-0458-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 09/21/2017] [Indexed: 06/07/2023]
Abstract
The slow kinetic phases of the chlorophyll a fluorescence transient (induction) are valuable tools in studying dynamic regulation of light harvesting, light energy distribution between photosystems, and heat dissipation in photosynthetic organisms. However, the origin of these phases are not yet fully understood. This is especially true in the case of prokaryotic oxygenic photoautotrophs, the cyanobacteria. To understand the origin of the slowest (tens of minutes) kinetic phase, the M-T fluorescence decline, in the context of light acclimation of these globally important microorganisms, we have compared spectrally resolved fluorescence induction data from the wild type Synechocystis sp. PCC 6803 cells, using orange (λ = 593 nm) actinic light, with those of mutants, ΔapcD and ΔOCP, that are unable to perform either state transition or fluorescence quenching by orange carotenoid protein (OCP), respectively. Our results suggest a multiple origin of the M-T decline and reveal a complex interplay of various known regulatory processes in maintaining the redox homeostasis of a cyanobacterial cell. In addition, they lead us to suggest that a new type of regulatory process, operating on the timescale of minutes to hours, is involved in dissipating excess light energy in cyanobacteria.
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Affiliation(s)
- Gábor Bernát
- Laboratory of Photosynthesis, Institute of Microbiology, Academy of Sciences, Opatovicky mlyn, 379 81, Třeboň, Czech Republic.
| | - Gábor Steinbach
- Laboratory of Photosynthesis, Institute of Microbiology, Academy of Sciences, Opatovicky mlyn, 379 81, Třeboň, Czech Republic
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, Szeged, 6726, Hungary
| | - Radek Kaňa
- Laboratory of Photosynthesis, Institute of Microbiology, Academy of Sciences, Opatovicky mlyn, 379 81, Třeboň, Czech Republic
| | - Amarendra N Misra
- Centre for Life Sciences, Central University of Jharkand, Ranchi, 835205, Jharkand, India
- Khallikote Cluster University, Berhampur, 76001, Odisha, India
| | - Ondřej Prašil
- Laboratory of Photosynthesis, Institute of Microbiology, Academy of Sciences, Opatovicky mlyn, 379 81, Třeboň, Czech Republic
- Faculty of Sciences, University of South Bohemia in České Budějovice, 37005, Ceske Budejovice, Czech Republic
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Kodru S, Malavath T, Devadasu E, Nellaepalli S, Stirbet A, Subramanyam R. The slow S to M rise of chlorophyll a fluorescence reflects transition from state 2 to state 1 in the green alga Chlamydomonas reinhardtii. PHOTOSYNTHESIS RESEARCH 2015; 125:219-31. [PMID: 25663564 DOI: 10.1007/s11120-015-0084-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 01/08/2015] [Indexed: 05/03/2023]
Abstract
The green alga Chlamydomonas (C.) reinhardtii is a model organism for photosynthesis research. State transitions regulate redistribution of excitation energy between photosystem I (PS I) and photosystem II (PS II) to provide balanced photosynthesis. Chlorophyll (Chl) a fluorescence induction (the so-called OJIPSMT transient) is a signature of several photosynthetic reactions. Here, we show that the slow (seconds to minutes) S to M fluorescence rise is reduced or absent in the stt7 mutant (which is locked in state 1) in C. reinhardtii. This suggests that the SM rise in wild type C. reinhardtii may be due to state 2 (low fluorescence state; larger antenna in PS I) to state 1 (high fluorescence state; larger antenna in PS II) transition, and thus, it can be used as an efficient and quick method to monitor state transitions in algae, as has already been shown in cyanobacteria (Papageorgiou et al. 1999, 2007; Kaňa et al. 2012). We also discuss our results on the effects of (1) 3-(3,4-dichlorophenyl)-1,4-dimethyl urea, an inhibitor of electron transport; (2) n-propyl gallate, an inhibitor of alternative oxidase (AOX) in mitochondria and of plastid terminal oxidase in chloroplasts; (3) salicylhydroxamic acid, an inhibitor of AOX in mitochondria; and (4) carbonyl cyanide p-trifluoromethoxyphenylhydrazone, an uncoupler of phosphorylation, which dissipates proton gradient across membranes. Based on the data presented in this paper, we conclude that the slow PSMT fluorescence transient in C. reinhardtii is due to the superimposition of, at least, two phenomena: qE dependent non-photochemical quenching of the excited state of Chl, and state transitions.
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Affiliation(s)
- Sireesha Kodru
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, 500 046, India
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Stamatakis K, Tsimilli-Michael M, Papageorgiou GC. On the question of the light-harvesting role of β-carotene in photosystem II and photosystem I core complexes. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 81:121-7. [PMID: 24529497 DOI: 10.1016/j.plaphy.2014.01.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 01/22/2014] [Indexed: 05/24/2023]
Abstract
β-Carotene is the only carotenoid present in the core complexes of Photosystems I and II. Its proximity to chlorophyll a molecules enables intermolecular electronic interactions, including β-carotene to chlorophyll a electronic excitation transfers. However, it has been well documented that, compared to chlorophylls and to phycobilins, the light harvesting efficiency of β-carotenes for photosynthetic O2 evolution is poor. This is more evident in cyanobacteria than in plants and algae because they lack accessory light harvesting pigments with absorptions that overlap the β-carotene absorption. In the present work we investigated the light harvesting role of β-carotenes in the cyanobacterium Synechococcus sp. PCC 7942 using selective β-carotene excitation and selective Photosystem detection of photo-induced electron transport to and from the intersystem plastoquinones (the plastoquinone pool). We report that, although selectively excited β-carotenes transfer electronic excitation to the chlorophyll a of both photosystems, they enable only the oxidation of the plastoquinone pool by Photosystem I but not its reduction by Photosystem II. This may suggest a light harvesting role for the β-carotenes of the Photosystem I core complex but not for those of the Photosystem II core complex. According to the present investigation, performed with whole cyanobacterial cells, the lower photosynthesis yields measured with β-Car-absorbed light can be attributed to the different excitation trapping efficiencies in the reaction centers of PSI and PSII.
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Affiliation(s)
- Kostas Stamatakis
- Institute of Biosciences and Applications, National Center for Scentific Research Demokritos, Aghia Paraskevi, Attikis 15310, Greece.
| | | | - George C Papageorgiou
- Institute of Biosciences and Applications, National Center for Scentific Research Demokritos, Aghia Paraskevi, Attikis 15310, Greece
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Stamatakis K, Papageorgiou GC. ΔpH-dependent non-photochemical quenching (qE) of excited chlorophylls in the photosystem II core complex of the freshwater cyanobacterium Synechococcus sp PCC 7942. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 81:184-189. [PMID: 24793104 DOI: 10.1016/j.plaphy.2014.04.004] [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: 12/16/2013] [Accepted: 04/08/2014] [Indexed: 06/03/2023]
Abstract
Light-induced and lumen acidity-dependent quenching (qE) of excited chlorophylls (Chl) in vivo has been amply documented in plants and algae, but not in cyanobacteria, using primarily the saturation pulse method of quenching analysis which is applied to continuously illuminated samples. This method is unsuitable for cyanobacteria because the background illumination elicits in them a very large Chl a fluorescence signal, due to a state 2 to state 1 transition, which masks fluorescence changes due to other causes. We investigated the qE problem in the cyanobacterium Synechococcus sp. PCC 7942 using a kinetic method (Chl a fluorescence induction) with which qE can be examined before the onset of the state 2 to state 1 transition and the attendant rise of Chl a fluorescence. Our results confirm the existence of a qE mechanism that operates on excited Chls a in Photosystem II core complexes of cyanobacteria.
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Affiliation(s)
- Kostas Stamatakis
- Institute of Biosciences and Applications, National Center for Scientific Research Demokritos, Aghia Paraskevi Attikis 15310, Greece.
| | - George C Papageorgiou
- Institute of Biosciences and Applications, National Center for Scientific Research Demokritos, Aghia Paraskevi Attikis 15310, Greece
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Summerfield TC, Crawford TS, Young RD, Chua JPS, Macdonald RL, Sherman LA, Eaton-Rye JJ. Environmental pH affects photoautotrophic growth of Synechocystis sp. PCC 6803 strains carrying mutations in the lumenal proteins of PSII. PLANT & CELL PHYSIOLOGY 2013; 54:859-74. [PMID: 23444302 DOI: 10.1093/pcp/pct036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Synechocystis sp. strain PCC 6803 grows photoautotrophically across a broad pH range, but wild-type cultures reach a higher density at elevated pH; however, photoheterotrophic growth is similar at high and neutral pH. A number of PSII mutants each lacking at least one lumenal extrinsic protein, and carrying a second PSII lumenal mutation, are able to grow photoautotrophically in BG-11 medium at pH 10.0, but not pH 7.5. We investigated the basis of this pH effect and observed no pH-specific change in variable fluorescence yield from PSII centers of the wild type or the pH-dependent ΔPsbO:ΔPsbU and ΔPsbV:ΔCyanoQ strains; however, 77 K fluorescence emission spectra indicated increased coupling of the phycobilisome (PBS) antenna at pH 10.0 in all mutants. DNA microarray data showed a cell-wide response to transfer from pH 10.0 to pH 7.5, including decreased mRNA levels of a number of oxidative stress-responsive transcripts. We hypothesize that this transcriptional response led to increased tolerance against reactive oxygen species and in particular singlet oxygen. This response enabled photoautotrophic growth of the PSII mutants at pH 10.0. This hypothesis was supported by increased resistance of all strains to rose bengal at pH 10.0 compared with pH 7.5.
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Affiliation(s)
- Tina C Summerfield
- Department of Botany, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.
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Kaňa R, Kotabová E, Komárek O, Sedivá B, Papageorgiou GC, Govindjee, Prášil O. The slow S to M fluorescence rise in cyanobacteria is due to a state 2 to state 1 transition. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1237-47. [PMID: 22402228 DOI: 10.1016/j.bbabio.2012.02.024] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 02/13/2012] [Accepted: 02/20/2012] [Indexed: 11/17/2022]
Abstract
In dark-adapted plants and algae, chlorophyll a fluorescence induction peaks within 1s after irradiation due to well documented photochemical and non-photochemical processes. Here we show that the much slower fluorescence rise in cyanobacteria (the so-called "S to M rise" in tens of seconds) is due to state 2 to state 1 transition. This has been demonstrated in particular for Synechocystis PCC6803, using its RpaC(-) mutant (locked in state 1) and its wild-type cells kept in hyperosmotic suspension (locked in state 2). In both cases, the inhibition of state changes correlates with the disappearance of the S to M fluorescence rise, confirming its assignment to the state 2 to state 1 transition. The general physiological relevance of the SM rise is supported by its occurrence in several cyanobacterial strains: Synechococcus (PCC 7942, WH 5701) and diazotrophic single cell cyanobacterium (Cyanothece sp. ATCC 51142). We also show here that the SM fluorescence rise, and also the state transition changes are less prominent in filamentous diazotrophic cyanobacterium Nostoc sp. (PCC 7120) and absent in phycobilisome-less cyanobacterium Prochlorococcus marinus PCC 9511. Surprisingly, it is also absent in the phycobiliprotein rod containing Acaryochloris marina (MBIC 11017). All these results show that the S to M fluorescence rise reflects state 2 to state 1 transition in cyanobacteria with phycobilisomes formed by rods and core parts. We show that the pronounced SM fluorescence rise may reflect a protective mechanism for excess energy dissipation in those cyanobacteria (e.g. in Synechococcus PCC 7942) that are less efficient in other protective mechanisms, such as blue light induced non-photochemical quenching. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
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Affiliation(s)
- Radek Kaňa
- Institute of Microbiology, Academy of Sciences, Třeboň, Czech Republic.
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Papageorgiou GC, Govindjee. Photosystem II fluorescence: slow changes--scaling from the past. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2011; 104:258-70. [PMID: 21530301 DOI: 10.1016/j.jphotobiol.2011.03.008] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 03/14/2011] [Accepted: 03/14/2011] [Indexed: 11/25/2022]
Abstract
With the advent of photoelectric devices (photocells, photomultipliers) in the 1930s, fluorometry of chlorophyll (Chl) a in vivo emerged as a major method in the science of photosynthesis. Early researchers employed fluorometry primarily for two tasks: to elucidate the role in photosynthesis, if any, of other plant pigments, such as Chl b, Chl c, carotenoids and phycobilins; and to use it as a convenient inverse measure of photosynthetic activity. In pursuing the latter task, it became apparent that Chl a fluorescence emission is influenced (i) by redox active Chl a molecules in the reaction center of photosystem (PS) II (photochemical quenching); (ii) by an electrochemical imbalance across the thylakoid membrane (high energy quenching); and (iii) by the size of the peripheral antennae of weakly fluorescent PSI and strongly fluorescent PSII in response to changes in the ambient light (state transitions). In this perspective we trace the historical evolution of our awareness of these concepts, particularly of the so-called 'State Transitions'.
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Affiliation(s)
- George C Papageorgiou
- National Center of Scientific Research Demokritos, Institute of Biology, Athens 15310, Greece.
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Spectral characteristic of fluorescence induction in a model cyanobacterium, Synechococcus sp. (PCC 7942). BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1170-8. [PMID: 19410552 DOI: 10.1016/j.bbabio.2009.04.013] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Revised: 03/24/2009] [Accepted: 04/15/2009] [Indexed: 11/24/2022]
Abstract
We present here three-dimensional time-wavelength-intensity displays of changes in variable fluorescence, during the O(JI)PSMT transient, observed in cyanobacterium at room temperature. We were able to measure contributions of individual chromophores to fluorescence spectra at various times of fluorescence induction (FI). The method was applied to a freshwater cyanobacterium, Synechococcus sp. (PCC 7942). Analysis of our experimental results provides the following new conclusions: (i) the main chlorophyll (Chl) a emission band at approximately 685 nm that originates in Photosystem (PS) II exhibits typical fast (OPS) and slow (SMT) FI kinetics with both orange (622 nm) and blue (464 nm) excitation. (ii) Similar kinetics are exhibited for its far-red emission satellite band centered at approximately 745 nm, where the PS II contribution predominates. (iii) A significant OPS-SMT-type kinetics of C-phycocyanin emission at approximately 650 nm are observed with the blue light excitation, but not with orange light excitation where the signal rose only slightly to a maximum. The induction of F650 was not caused by an admixture of the F685 fluorescence and thus our data show light-inducible and dark-reversible changes of phycobilin fluorescence in vivo. We discuss possible interpretations of this new observation.
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Tsimilli-Michael M, Stamatakis K, Papageorgiou GC. Dark-to-light transition in Synechococcus sp. PCC 7942 cells studied by fluorescence kinetics assesses plastoquinone redox poise in the dark and photosystem II fluorescence component and dynamics during state 2 to state 1 transition. PHOTOSYNTHESIS RESEARCH 2009; 99:243-55. [PMID: 19205920 DOI: 10.1007/s11120-009-9405-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2008] [Accepted: 01/12/2009] [Indexed: 05/08/2023]
Abstract
We investigated the dark-to-light transition in Synechococcus sp. PCC 7942 cells by a detailed analysis of fluorescence transients induced by strong red light. The transients, recorded with high data-acquisition, revealed all the steps of the fast (OJIP; 10(-5)-1 s) and slow phase (PSM(T); 1-10(3) s), kinetically distinguished with precision. Focusing on the OJIP-rise, we show, for the first time, how the variable to initial fluorescence ratio and the relative height of J-level can serve as indexes of the plastoquinone redox poise and the established state in the dark; hence, differences among cyanobacteria can be recognised in a simple way. Applying intermittent illumination (20-s light pulses separated by 10-s dark intervals) to induce dark-to-light transition and analysing the individual transients, we establish a method by which we determine the fluorescence component not originating from photosystem (PS) II and we assess PSII dynamics during state 2 to state 1 transition. The development of photochemical and non-photochemical quenching is also discussed, as well as evidences favouring the mobile antenna model.
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Role of phosphatidylglycerol in the function and assembly of Photosystem II reaction center, studied in a cdsA-inactivated PAL mutant strain of Synechocystis sp. PCC6803 that lacks phycobilisomes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1777:1184-94. [DOI: 10.1016/j.bbabio.2008.06.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 06/04/2008] [Accepted: 06/04/2008] [Indexed: 11/24/2022]
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Papageorgiou GC, Tsimilli-Michael M, Stamatakis K. The fast and slow kinetics of chlorophyll a fluorescence induction in plants, algae and cyanobacteria: a viewpoint. PHOTOSYNTHESIS RESEARCH 2007; 94:275-90. [PMID: 17665151 DOI: 10.1007/s11120-007-9193-x] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Accepted: 05/03/2007] [Indexed: 05/16/2023]
Abstract
The light-induced/dark-reversible changes in the chlorophyll (Chl) a fluorescence of photosynthetic cells and membranes in the mus-to-several min time window (fluorescence induction, FI; or Kautsky transient) reflect quantum yield changes (quenching/de-quenching) as well as changes in the number of Chls a in photosystem II (PS II; state transitions). Both relate to excitation trapping in PS II and the ensuing photosynthetic electron transport (PSET), and to secondary PSET effects, such as ion translocation across thylakoid membranes and filling or depletion of post-PS II and post-PS I pools of metabolites. In addition, high actinic light doses may depress Chl a fluorescence irreversibly (photoinhibitory lowering; q(I)). FI has been studied quite extensively in plants an algae (less so in cyanobacteria) as it affords a low resolution panoramic view of the photosynthesis process. Total FI comprises two transients, a fast initial (OPS; for Origin, Peak, Steady state) and a second slower transient (SMT; for Steady state, Maximum, Terminal state), whose details are characteristically different in eukaryotic (plants and algae) and prokaryotic (cyanobacteria) oxygenic photosynthetic organisms. In the former, maximal fluorescence output occurs at peak P, with peak M lying much lower or being absent, in which case the PSMT phases are replaced by a monotonous PT fluorescence decay. In contrast, in phycobilisome (PBS)-containing cyanobacteria maximal fluorescence occurs at M which lies much higher than peak P. It will be argued that this difference is caused by a fluorescence lowering trend (state 1 --> 2 transition) that dominates the FI pattern of plants and algae, and correspondingly by a fluorescence increasing trend (state 2 --> 1 transition) that dominates the FI of PBS-containing cyanobacteria. Characteristically, however, the FI pattern of the PBS-minus cyanobacterium Acaryochloris marina resembles the FI patterns of algae and plants and not of the PBS-containing cyanobacteria.
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Affiliation(s)
- George C Papageorgiou
- National Center for Scientific Research Demokritos, Institute of Biology, Athens, 153 10, Greece.
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