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Calzadilla PI, Song J, Gallois P, Johnson GN. Proximity to Photosystem II is necessary for activation of Plastid Terminal Oxidase (PTOX) for photoprotection. Nat Commun 2024; 15:287. [PMID: 38177155 PMCID: PMC10767095 DOI: 10.1038/s41467-023-44454-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 12/14/2023] [Indexed: 01/06/2024] Open
Abstract
The Plastid Terminal Oxidase (PTOX) is a chloroplast localized plastoquinone oxygen oxidoreductase suggested to have the potential to act as a photoprotective safety valve for photosynthesis. However, PTOX overexpression in plants has been unsuccessful at inducing photoprotection, and the factors that control its activity remain elusive. Here, we show that significant PTOX activity is induced in response to high light in the model species Eutrema salsugineum and Arabidopsis thaliana. This activation correlates with structural reorganization of the thylakoid membrane. Over-expression of PTOX in mutants of Arabidopsis thaliana perturbed in thylakoid stacking also results in such activity, in contrast to wild type plants with normal granal structure. Further, PTOX activation protects against photoinhibition of Photosystem II and reduces reactive oxygen production under stress conditions. We conclude that structural re-arrangements of the thylakoid membranes, bringing Photosystem II and PTOX into proximity, are both required and sufficient for PTOX to act as a Photosystem II sink and play a role in photoprotection.
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Affiliation(s)
- Pablo Ignacio Calzadilla
- Department of Earth and Environmental Sciences, Faculty of Science and Engineering, University of Manchester, Manchester, United Kingdom
| | - Junliang Song
- Department of Earth and Environmental Sciences, Faculty of Science and Engineering, University of Manchester, Manchester, United Kingdom
| | - Patrick Gallois
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Giles Nicholas Johnson
- Department of Earth and Environmental Sciences, Faculty of Science and Engineering, University of Manchester, Manchester, United Kingdom.
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2
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Kharabian-Masouleh A, Furtado A, Alsubaie B, Al-Dossary O, Wu A, Al-Mssalem I, Henry R. Loss of plastid ndh genes in an autotrophic desert plant. Comput Struct Biotechnol J 2023; 21:5016-5027. [PMID: 37867970 PMCID: PMC10589726 DOI: 10.1016/j.csbj.2023.10.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 10/12/2023] [Accepted: 10/13/2023] [Indexed: 10/24/2023] Open
Abstract
Plant plastid genomes are highly conserved with most flowering plants having the same complement of essential plastid genes. Here, we report the loss of five of the eleven NADH dehydrogenase subunit genes (ndh) in the plastid of a desert plant jojoba (Simmondsia chinensis). The plastid genome of jojoba was 156,496 bp with one large single copy region (LSC), a very small single copy region (SSC) and two expanded inverted repeats (IRA + IRB). The NADH dehydrogenase (NDH) complex is comprised of several protein subunits, encoded by the ndh genes of the plastome and the nucleus. The ndh genes are critical to the proper functioning of the photosynthetic electron transport chain and protection of plants from oxidative stress. Most plants are known to contain all eleven ndh genes. Plants with missing or defective ndh genes are often heterotrophs either due to their complete or holo- or myco- parasitic nature. Plants with a defective NDH complex, caused by the deletion/pseudogenisation of some or all the ndh genes, survive in milder climates suggesting the likely extinction of plant lineages lacking these genes under harsh climates. Interestingly, some autotrophic plants do exist without ndh gene/s and can cope with high or low light. This implies that these plants are protected from oxidative stress by mechanisms excluding ndh genes. Jojoba has evolved mechanisms to cope with a non-functioning NDH complex and survives in extreme desert conditions with abundant sunlight and limited water.
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Affiliation(s)
- Ardashir Kharabian-Masouleh
- Queensland Alliance for Innovation in Food and Agriculture (QAAFI), The University of Queensland, Carmody Rd, St Lucia, QLD 4072, Australia
- ARC Centre of Excellence for Plant Success in Nature and Agriculture, The University of Queensland, Carmody Rd, St Lucia, QLD 4072, Australia
| | - Agnelo Furtado
- Queensland Alliance for Innovation in Food and Agriculture (QAAFI), The University of Queensland, Carmody Rd, St Lucia, QLD 4072, Australia
| | - Bader Alsubaie
- Queensland Alliance for Innovation in Food and Agriculture (QAAFI), The University of Queensland, Carmody Rd, St Lucia, QLD 4072, Australia
- College of Agriculture and Food Sciences, King Faisal University (KFU), Al Hofuf, 36362 Saudi Arabia
| | - Othman Al-Dossary
- Queensland Alliance for Innovation in Food and Agriculture (QAAFI), The University of Queensland, Carmody Rd, St Lucia, QLD 4072, Australia
- College of Agriculture and Food Sciences, King Faisal University (KFU), Al Hofuf, 36362 Saudi Arabia
| | - Alex Wu
- Queensland Alliance for Innovation in Food and Agriculture (QAAFI), The University of Queensland, Carmody Rd, St Lucia, QLD 4072, Australia
| | - Ibrahim Al-Mssalem
- College of Agriculture and Food Sciences, King Faisal University (KFU), Al Hofuf, 36362 Saudi Arabia
| | - Robert Henry
- Queensland Alliance for Innovation in Food and Agriculture (QAAFI), The University of Queensland, Carmody Rd, St Lucia, QLD 4072, Australia
- ARC Centre of Excellence for Plant Success in Nature and Agriculture, The University of Queensland, Carmody Rd, St Lucia, QLD 4072, Australia
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3
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Tikhonov AN. Electron Transport in Chloroplasts: Regulation and Alternative Pathways of Electron Transfer. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1438-1454. [PMID: 38105016 DOI: 10.1134/s0006297923100036] [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: 06/21/2023] [Revised: 07/09/2023] [Accepted: 07/09/2023] [Indexed: 12/19/2023]
Abstract
This work represents an overview of electron transport regulation in chloroplasts as considered in the context of structure-function organization of photosynthetic apparatus in plants. Main focus of the article is on bifurcated oxidation of plastoquinol by the cytochrome b6f complex, which represents the rate-limiting step of electron transfer between photosystems II and I. Electron transport along the chains of non-cyclic, cyclic, and pseudocyclic electron flow, their relationships to generation of the trans-thylakoid difference in electrochemical potentials of protons in chloroplasts, and pH-dependent mechanisms of regulation of the cytochrome b6f complex are considered. Redox reactions with participation of molecular oxygen and ascorbate, alternative mediators of electron transport in chloroplasts, have also been discussed.
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4
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Saroussi S, Redekop P, Karns DAJ, Thomas DC, Wittkopp TM, Posewitz MC, Grossman AR. Restricting electron flow at cytochrome b6f when downstream electron acceptors are severely limited. PLANT PHYSIOLOGY 2023; 192:789-804. [PMID: 36960590 PMCID: PMC10231464 DOI: 10.1093/plphys/kiad185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 06/01/2023]
Abstract
Photosynthetic organisms frequently experience abiotic stress that restricts their growth and development. Under such circumstances, most absorbed solar energy cannot be used for CO2 fixation and can cause the photoproduction of reactive oxygen species (ROS) that can damage the photosynthetic reaction centers of PSI and PSII, resulting in a decline in primary productivity. This work describes a biological "switch" in the green alga Chlamydomonas reinhardtii that reversibly restricts photosynthetic electron transport (PET) at the cytochrome b6f (Cyt b6f) complex when the capacity for accepting electrons downstream of PSI is severely limited. We specifically show this restriction in STARCHLESS6 (sta6) mutant cells, which cannot synthesize starch when they are limited for nitrogen (growth inhibition) and subjected to a dark-to-light transition. This restriction represents a form of photosynthetic control that causes diminished electron flow to PSI and thereby prevents PSI photodamage but does not appear to rely on a ΔpH. Furthermore, when electron flow is restricted, the plastid alternative oxidase (PTOX) becomes active, functioning as an electron valve that dissipates some excitation energy absorbed by PSII and allows the formation of a proton motive force (PMF) that would drive some ATP production (potentially sustaining PSII repair and nonphotochemical quenching [NPQ]). The restriction at the Cyt b6f complex can be gradually relieved with continued illumination. This study provides insights into how PET responds to a marked reduction in availability of downstream electron acceptors and the protective mechanisms involved.
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Affiliation(s)
- Shai Saroussi
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Petra Redekop
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Devin A J Karns
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Dylan C Thomas
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Tyler M Wittkopp
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA 94305, USA
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Matthew C Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Arthur R Grossman
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA 94305, USA
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5
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Shimakawa G. Electron transport in cyanobacterial thylakoid membranes: Are cyanobacteria simple models for photosynthetic organisms? JOURNAL OF EXPERIMENTAL BOTANY 2023:erad118. [PMID: 37025010 DOI: 10.1093/jxb/erad118] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Indexed: 06/19/2023]
Abstract
Cyanobacteria are structurally the simplest oxygenic phototrophs, which makes it difficult to understand the regulation of photosynthesis because the photosynthetic and respiratory processes share the same thylakoid membranes and cytosolic space. This review aimed to summarise the molecular mechanisms and in vivo activities of electron transport in cyanobacterial thylakoid membranes based on the latest progress in photosynthesis research in cyanobacteria. Photosynthetic linear electron transport for CO2 assimilation has the dominant electron flux in the thylakoid membranes. The capacity of O2 photoreduction in cyanobacteria is comparable to the photosynthetic CO2 assimilation, which is mediated by flavodiiron proteins. Additionally, cyanobacterial thylakoid membranes harbour the significant electron flux of respiratory electron transport through a homologue of respiratory complex I, which is also recognized as the part of cyclic electron transport chain if it is coupled with photosystem I in the light. Further, O2-independent alternative electron transports through hydrogenase and nitrate reductase function with reduced ferredoxin as the electron donor. Whereas all these electron transports are recently being understood one by one, the complexity as the whole regulatory system remains to be uncovered in near future.
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Affiliation(s)
- Ginga Shimakawa
- Department of Bioscience, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan
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6
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Tilney CL, Hubbard KA. Expression of nuclear-encoded, haptophyte-derived ftsH genes support extremely rapid PSII repair and high-light photoacclimation in Karenia brevis (Dinophyceae). HARMFUL ALGAE 2022; 118:102295. [PMID: 36195421 DOI: 10.1016/j.hal.2022.102295] [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: 05/17/2022] [Revised: 07/28/2022] [Accepted: 08/01/2022] [Indexed: 06/16/2023]
Abstract
Karenia brevis, a neurotoxic dinoflagellate that produces brevetoxins, is endemic to the Gulf of Mexico and can grow at high irradiances typical of surface waters found there. To build upon a growing number of studies addressing high-light tolerance in K. brevis, specific photobiology and molecular mechanisms underlying this capacity were evaluated in culture. Since photosystem II (PSII) repair cycle activity can be crucial to high light tolerance in plants and algae, the present study assessed this capacity in K. brevis and characterized the ftsH-like genes which are fundamental to this process. Compared with cultures grown in low-light, cultures grown in high-light showed a 65-fold increase in PSII photoinactivation, a ∼50-fold increase in PSII repair, enhanced nonphotochemical quenching (NPQ), and depressed Fv/Fm. Repair rates were among the fastest reported in phytoplankton. Publicly available K. brevis transcriptomes (MMETSP) were queried for ftsH-like sequences and refined with additional sequencing from two K. brevis strains. The genes were phylogenetically related to haptophyte orthologs, implicating acquisition during tertiary endosymbiosis. RT-qPCR of three of the four ftsH-like homologs revealed that poly-A tails predominated in all homologs, and that the most highly expressed homolog had a 5' splice leader and amino-acid motifs characteristic of chloroplast targeting, indicating nuclear encoding for this plastid-targeted gene. High-light cultures showed a ∼1.5-fold upregulation in mRNA expression of the thylakoid-associated genes. Overall, in conjunction with NPQ mechanisms, rapid PSII repair mediated by a haptophyte-derived ftsH prevents chronic photoinhibition in K. brevis. Our findings continue to build the case that high-light photobiology-supported by the acquisition and maintenance of tertiary endosymbiotic genes-is critical to the success of K. brevis in the Gulf of Mexico.
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Affiliation(s)
- Charles L Tilney
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, St. Petersburg, FL, 33701, USA; Institut des Sciences de la Mer de Rimouski, Université du Québec à Rimouski, Rimouski, Québec, G5M 1L7, Canada.
| | - Katherine A Hubbard
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, St. Petersburg, FL, 33701, USA
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7
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Suslichenko IS, Trubitsin BV, Vershubskii AV, Tikhonov AN. The noninvasive monitoring of the redox status of photosynthetic electron transport chains in Hibiscus rosa-sinensis and Tradescantia leaves. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 185:233-243. [PMID: 35716433 DOI: 10.1016/j.plaphy.2022.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 05/13/2022] [Accepted: 06/01/2022] [Indexed: 06/15/2023]
Abstract
We present an approach to the noninvasive determination of the electron capacity of the intersystem pool of electron carriers in chloroplasts in situ. As apt experimental models, we used the leaves of Hibiscus rosa-sinensis and Tradescantia species. Electron paramagnetic resonance and optical response of P700 (the primary electron donor in Photosystem I) were applied to measuring electron transport in chloroplasts. Electron capacities of the intersystem electron transport chain (ETC) were determined from redox transients of P700 upon chromatic transitions (white light → far-red light). During the induction period, we observed the nonmonotonic changes in the number of electron equivalents in the intersystem ETC per P700 (parameter Q). In Hibiscus rosa-sinensis, the light-induced rise of Q from ≈2.5 (in the dark) to Q ≈ 12 was followed by its decrease to Q ≈ 6. The data obtained are discussed in the context of pH-dependent regulation of electron transport in chloroplasts, which provides the well-balanced operation of the intersystem ETC. The decay of Q is explained by the attenuation of Photosystem II activity due to the lumen acidification and the acceleration of plastoquinol re-oxidation as a result of the Calvin-Benson cycle activation. Our computer model of electron and proton transport coupled to ATP synthesis in chloroplasts was used to analyze the up and down feedbacks responsible for pH-dependent regulation of electron transport in chloroplasts. The procedures introduced here may be important for subsequent works aimed at defining the plastoquinone participation in regulation of photosynthetic processes in chloroplasts in situ.
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Affiliation(s)
- Igor S Suslichenko
- Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Boris V Trubitsin
- Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow, Russia
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8
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Porcar-Castell A, Malenovský Z, Magney T, Van Wittenberghe S, Fernández-Marín B, Maignan F, Zhang Y, Maseyk K, Atherton J, Albert LP, Robson TM, Zhao F, Garcia-Plazaola JI, Ensminger I, Rajewicz PA, Grebe S, Tikkanen M, Kellner JR, Ihalainen JA, Rascher U, Logan B. Chlorophyll a fluorescence illuminates a path connecting plant molecular biology to Earth-system science. NATURE PLANTS 2021; 7:998-1009. [PMID: 34373605 DOI: 10.1038/s41477-021-00980-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 06/28/2021] [Indexed: 05/27/2023]
Abstract
For decades, the dynamic nature of chlorophyll a fluorescence (ChlaF) has provided insight into the biophysics and ecophysiology of the light reactions of photosynthesis from the subcellular to leaf scales. Recent advances in remote sensing methods enable detection of ChlaF induced by sunlight across a range of larger scales, from using instruments mounted on towers above plant canopies to Earth-orbiting satellites. This signal is referred to as solar-induced fluorescence (SIF) and its application promises to overcome spatial constraints on studies of photosynthesis, opening new research directions and opportunities in ecology, ecophysiology, biogeochemistry, agriculture and forestry. However, to unleash the full potential of SIF, intensive cross-disciplinary work is required to harmonize these new advances with the rich history of biophysical and ecophysiological studies of ChlaF, fostering the development of next-generation plant physiological and Earth-system models. Here, we introduce the scale-dependent link between SIF and photosynthesis, with an emphasis on seven remaining scientific challenges, and present a roadmap to facilitate future collaborative research towards new applications of SIF.
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Affiliation(s)
- Albert Porcar-Castell
- Optics of Photosynthesis Laboratory, Institute for Atmospheric and Earth System Research (INAR)/Forest Sciences, Viikki Plant Science Center (ViPS), University of Helsinki, Helsinki, Finland.
| | - Zbyněk Malenovský
- School of Geography, Planning, and Spatial Sciences, College of Sciences Engineering and Technology, University of Tasmania, Hobart, Tasmania, Australia
| | - Troy Magney
- Department of Plant Sciences, University of California, Davis, Davis, CA, USA
| | - Shari Van Wittenberghe
- Optics of Photosynthesis Laboratory, Institute for Atmospheric and Earth System Research (INAR)/Forest Sciences, Viikki Plant Science Center (ViPS), University of Helsinki, Helsinki, Finland
- Laboratory of Earth Observation, University of Valencia, Paterna, Spain
| | - Beatriz Fernández-Marín
- Department of Botany, Ecology and Plant Physiology, University of La Laguna (ULL), Tenerife, Spain
| | - Fabienne Maignan
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Yongguang Zhang
- International Institute for Earth System Sciences, Nanjing University, Nanjing, China
| | - Kadmiel Maseyk
- School of Environment, Earth and Ecosystem Sciences, The Open University, Milton Keynes, UK
| | - Jon Atherton
- Optics of Photosynthesis Laboratory, Institute for Atmospheric and Earth System Research (INAR)/Forest Sciences, Viikki Plant Science Center (ViPS), University of Helsinki, Helsinki, Finland
| | - Loren P Albert
- Institute at Brown for Environment and Society, Brown University, Providence, RI, USA
- Biology Department, West Virginia University, Morgantown, WV, USA
| | - Thomas Matthew Robson
- Organismal and Evolutionary Biology, Viikki Plant Science Centre (ViPS), Faculty of Biological and Environmental Science, University of Helsinki, Helsinki, Finland
| | - Feng Zhao
- School of Instrumentation Science and Opto-Electronics Engineering, Beihang University, Beijing, China
| | | | - Ingo Ensminger
- Department of Biology, Graduate Programs in Cell & Systems Biology and Ecology & Evolutionary Biology, University of Toronto, Mississauga, Ontario, Canada
| | - Paulina A Rajewicz
- Optics of Photosynthesis Laboratory, Institute for Atmospheric and Earth System Research (INAR)/Forest Sciences, Viikki Plant Science Center (ViPS), University of Helsinki, Helsinki, Finland
| | - Steffen Grebe
- Molecular Plant Biology, University of Turku, Turku, Finland
| | - Mikko Tikkanen
- Molecular Plant Biology, University of Turku, Turku, Finland
| | - James R Kellner
- Institute at Brown for Environment and Society, Brown University, Providence, RI, USA
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA
| | - Janne A Ihalainen
- Nanoscience Center, Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Uwe Rascher
- Institute of Bio- and Geosciences, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Barry Logan
- Biology Department, Bowdoin College, Brunswick, ME, USA
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Tan Y, Zhang QS, Zhao W, Liu Z, Ma MY, Zhong MY, Wang MX, Xu B. Chlororespiration Serves as Photoprotection for the Photo-Inactivated Oxygen-Evolving Complex in Zostera marina, a Marine Angiosperm. PLANT & CELL PHYSIOLOGY 2020; 61:1517-1529. [PMID: 32492141 DOI: 10.1093/pcp/pcaa075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 05/28/2020] [Indexed: 06/11/2023]
Abstract
As an alternative electron sink, chlororespiration, comprising the NAD(P)H dehydrogenase complex and plastid terminal plastoquinone oxidase, may play a significant role in sustaining the redox equilibrium between stroma and thylakoid membrane. This study identified a distinct role for chlororespiration in the marine angiosperm Zostera marina, whose oxygen-evolving complex (OEC) is prone to photo-inactivation as a result of its inherent susceptibility to excess irradiation. The strong connectivity between OEC peripheral proteins and key chlororespiratory enzymes, as demonstrated in the interaction network of differentially expressed genes, suggested that the recovery of photo-inactivated OEC was connected with chlororespiration. Chlorophyll fluorescence, transcriptome and Western blot data verified a new physiological role for chlororespiration to function as photoprotection and generate a proton gradient across the thylakoid membrane for the recovery of photo-inactivated OEC. Chlororespiration was only activated in darkness following excess irradiation exposure, which might be related to electron deficiency in the electron transport chain because of the continuous impairment of the OEC. The activation of chlororespiration in Z. marina was prone to proactivity, which was also supported by the further activation of the oxidative pentose-phosphate pathway synthesizing NADPH to meet the demand of chlororespiration during darkness. This phenomenon is distinct from the common assumption that chlororespiration is prone to consuming redundant reducing power during the short transition phase from light to dark.
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Affiliation(s)
- Ying Tan
- Phycology Laboratory, Ocean School, Yantai University, Yantai 264005, PR China
| | - Quan Sheng Zhang
- Phycology Laboratory, Ocean School, Yantai University, Yantai 264005, PR China
| | - Wei Zhao
- Phycology Laboratory, Ocean School, Yantai University, Yantai 264005, PR China
| | - Zhe Liu
- Phycology Laboratory, Ocean School, Yantai University, Yantai 264005, PR China
| | - Ming Yu Ma
- Phycology Laboratory, Ocean School, Yantai University, Yantai 264005, PR China
| | - Ming Yu Zhong
- Phycology Laboratory, Ocean School, Yantai University, Yantai 264005, PR China
| | - Meng Xin Wang
- Phycology Laboratory, Ocean School, Yantai University, Yantai 264005, PR China
| | - Bin Xu
- Phycology Laboratory, Ocean School, Yantai University, Yantai 264005, PR China
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10
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Petrova EV, Kukarskikh GP, Krendeleva TE, Antal TK. The Mechanisms and Role of Photosynthetic Hydrogen Production by Green Microalgae. Microbiology (Reading) 2020. [DOI: 10.1134/s0026261720030169] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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11
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PGR5 and NDH-1 systems do not function as protective electron acceptors but mitigate the consequences of PSI inhibition. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148154. [PMID: 31935360 DOI: 10.1016/j.bbabio.2020.148154] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 12/06/2019] [Accepted: 01/08/2020] [Indexed: 11/21/2022]
Abstract
Avoidance of photoinhibition at photosystem (PS)I is based on synchronized function of PSII, PSI, Cytochrome b6f and stromal electron acceptors. Here, we used a special light regime, PSI photoinhibition treatment (PIT), in order to specifically inhibit PSI by accumulating excess electrons at the photosystem (Tikkanen and Grebe, 2018). In the analysis, Arabidopsis thaliana WT was compared to the pgr5 and ndho mutants, deficient in one of the two main cyclic electron transfer pathways described to function as protective alternative electron acceptors of PSI. The aim was to investigate whether the PGR5 (pgr5) and the type I NADH dehydrogenase (NDH-1) (ndho) systems protect PSI from excess electron stress and whether they help plants to cope with the consequences of PSI photoinhibition. First, our data reveals that neither PGR5 nor NDH-1 system protects PSI from a sudden burst of electrons. This strongly suggests that these systems in Arabidopsis thaliana do not function as direct acceptors of electrons delivered from PSII to PSI - contrasting with the flavodiiron proteins that were found to make Physcomitrella patens PSI resistant to the PIT. Second, it is demonstrated that under light-limiting conditions, the electron transfer rate at PSII is linearly dependent on the amount of functional PSI in all genotypes, while under excess light, the PGR5-dependent control of electron flow at the Cytochrome b6f complex overrides the effect of PSI inhibition. Finally, the PIT is shown to increase the amount of PGR5 and NDH-1 as well as of PTOX, suggesting that they mitigate further damage to PSI after photoinhibition rather than protect against it.
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12
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Laeseke P, Bartsch I, Bischof K. Effects of kelp canopy on underwater light climate and viability of brown algal spores in Kongsfjorden (Spitsbergen). Polar Biol 2019. [DOI: 10.1007/s00300-019-02537-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Kennedy F, Martin A, Bowman JP, Wilson R, McMinn A. Dark metabolism: a molecular insight into how the Antarctic sea-ice diatom Fragilariopsis cylindrus survives long-term darkness. THE NEW PHYTOLOGIST 2019; 223:675-691. [PMID: 30985935 PMCID: PMC6617727 DOI: 10.1111/nph.15843] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 04/02/2019] [Indexed: 05/27/2023]
Abstract
Light underneath Antarctic sea-ice is below detectable limits for up to 4 months of the year. The ability of Antarctic sea-ice diatoms to survive this prolonged darkness relies on their metabolic capability. This study is the first to examine the proteome of a prominent sea-ice diatom in response to extended darkness, focusing on the protein-level mechanisms of dark survival. The Antarctic diatom Fragilariopsis cylindrus was grown under continuous light or darkness for 120 d. The whole cell proteome was quantitatively analysed by nano-LC-MS/MS to investigate metabolic changes that occur during sustained darkness and during recovery under illumination. Enzymes of metabolic pathways, particularly those involved in respiratory processes, tricarboxylic acid cycle, glycolysis, the Entner-Doudoroff pathway, the urea cycle and the mitochondrial electron transport chain became more abundant in the dark. Within the plastid, carbon fixation halted while the upper sections of the glycolysis, gluconeogenesis and pentose phosphate pathways became less active. We have discovered how F. cylindrus utilises an ancient alternative metabolic mechanism that enables its capacity for long-term dark survival. By sustaining essential metabolic processes in the dark, F. cylindrus retains the functionality of the photosynthetic apparatus, ensuring rapid recovery upon re-illumination.
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Affiliation(s)
- Fraser Kennedy
- Institute for Marine and Antarctic StudiesUniversity of TasmaniaHobart7000TasmaniaAustralia
| | - Andrew Martin
- Institute for Marine and Antarctic StudiesUniversity of TasmaniaHobart7000TasmaniaAustralia
| | - John P. Bowman
- Centre for Food Safety and InnovationTasmanian Institute of AgricultureHobart7000TasmaniaAustralia
| | - Richard Wilson
- Central Science LaboratoryUniversity of TasmaniaHobart7000TasmaniaAustralia
| | - Andrew McMinn
- Institute for Marine and Antarctic StudiesUniversity of TasmaniaHobart7000TasmaniaAustralia
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Suslichenko IS, Tikhonov AN. Photo-reducible plastoquinone pools in chloroplasts of Tradescentia plants acclimated to high and low light. FEBS Lett 2019; 593:788-798. [PMID: 30896038 DOI: 10.1002/1873-3468.13366] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 02/28/2019] [Accepted: 03/19/2019] [Indexed: 11/09/2022]
Abstract
In photosynthetic systems of oxygenic type, plastoquinone (PQ) molecules are reduced by photosystem II (PSII). The turnover of PQ determines the rate of PSII operation. PQ molecules are present in surplus with respect to PSII. In this work, using the pulse amplitude modulation-fluorometry technique, we quantified photo-reducible PQ pools in chloroplasts of two contrasting ecotypes of Tradescantia, acclimated either to low light (~ 100 μmol photons·m-2 ·s-1 , LL) or to high light (~ 1000 μmol photons·m-2 ·s-1 , HL). The LL-grown plants are characterized by higher capacity of rapidly reducible PQ pool ([PQ]0 /[PSII] ≈ 8) as compared to HL-grown plants of both species ([PQ]0 /[PSII] ≈ 4). The elevated content of PQ in LL plants favours photosynthetic electron flow at low-solar irradiance.
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Affiliation(s)
| | - Alexander N Tikhonov
- Faculty of Physics, M.V.Lomonosov Moscow State University, Russia.,N.M.Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
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15
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Torrado A, Ramírez-Moncayo C, Navarro JA, Mariscal V, Molina-Heredia FP. Cytochrome c 6 is the main respiratory and photosynthetic soluble electron donor in heterocysts of the cyanobacterium Anabaena sp. PCC 7120. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1860:60-68. [PMID: 30414412 DOI: 10.1016/j.bbabio.2018.11.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 10/20/2018] [Accepted: 11/07/2018] [Indexed: 12/27/2022]
Abstract
Cytochrome c6 is a soluble electron carrier, present in all known cyanobacteria, that has been replaced by plastocyanin in plants. Despite their high structural differences, both proteins have been reported to be isofunctional in cyanobacteria and green algae, acting as alternative electron carriers from the cytochrome b6-f complex to photosystem I or terminal oxidases. We have investigated the subcellular localization of both cytochrome c6 and plastocyanin in the heterocyst-forming cyanobacterium Anabaena sp. PCC 7120 grown in the presence of combined nitrogen and under diazotrophic conditions. Our studies conclude that cytochrome c6 is expressed at significant levels in heterocysts, even in the presence of copper, condition in which it is strongly repressed in vegetative cells. However, the copper-dependent regulation of plastocyanin is not altered in heterocysts. In addition, in heterocysts, cytochrome c6 has shown to be the main soluble electron carrier to cytochrome c oxidase-2 in respiration. A cytochrome c6 deletion mutant is unable to grow under diazotrophic conditions in the presence of copper, suggesting that cytochrome c6 plays an essential role in the physiology of heterocysts that cannot be covered by plastocyanin.
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Affiliation(s)
- Alejandro Torrado
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Sevilla, Spain; Departamento de Bioquímica Vegetal y Biología Molecular, Universidad de Sevilla, Sevilla, Spain
| | - Carmen Ramírez-Moncayo
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Sevilla, Spain
| | - José A Navarro
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Sevilla, Spain
| | - Vicente Mariscal
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Sevilla, Spain.
| | - Fernando P Molina-Heredia
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Sevilla, Spain; Departamento de Bioquímica Vegetal y Biología Molecular, Universidad de Sevilla, Sevilla, Spain.
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16
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Frailey DC, Chaluvadi SR, Vaughn JN, Coatney CG, Bennetzen JL. Gene loss and genome rearrangement in the plastids of five Hemiparasites in the family Orobanchaceae. BMC PLANT BIOLOGY 2018; 18:30. [PMID: 29409454 PMCID: PMC5801802 DOI: 10.1186/s12870-018-1249-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 01/30/2018] [Indexed: 05/09/2023]
Abstract
BACKGROUND The chloroplast genomes (plastome) of most plants are highly conserved in structure, gene content, and gene order. Parasitic plants, including those that are fully photosynthetic, often contain plastome rearrangements. These most notably include gene deletions that result in a smaller plastome size. The nature of gene loss and genome structural rearrangement has been investigated in several parasitic plants, but their timing and contributions to the adaptation of these parasites requires further investigation, especially among the under-studied hemi-parasites. RESULTS De novo sequencing, assembly and annotation of the chloroplast genomes of five photosynthetic parasites from the family Orobanchaceae were employed to investigate plastome dynamics. Four had major structural rearrangements, including gene duplications and gene losses, that differentiated the taxa. The facultative parasite Aureolaria virginica had the most similar genome content to its close non-parasitic relative, Lindenbergia philippensis, with similar genome size and organization, and no differences in gene content. In contrast, the facultative parasite Buchnera americana and three obligate parasites in the genus Striga all had enlargements of their plastomes, primarily caused by expansion within the large inverted repeats (IRs) that are a standard plastome feature. Some of these IR increases were shared by multiple investigated species, but others were unique to particular lineages. Gene deletions and pseudogenization were also both shared and lineage-specific, with particularly frequent and independent loss of the ndh genes involved in electron recycling. CONCLUSIONS Five new plastid genomes were fully assembled and compared. The results indicate that plastome instability is common in parasitic plants, even those that retain the need to perform essential plastid functions like photosynthesis. Gene losses were slow and not identical across taxa, suggesting that different lineages had different uses or needs for some of their plastome gene content, including genes involved in some aspects of photosynthesis. Recent repeat region extensions, some unique to terminal species branches, were observed after the divergence of the Buchnera/Striga clade, suggesting that this otherwise rare event has some special value in this lineage.
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Affiliation(s)
| | | | - Justin N. Vaughn
- Department of Genetics, University of Georgia, Athens, GA 30677 USA
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17
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Huang W, Yang YJ, Zhang SB. Specific roles of cyclic electron flow around photosystem I in photosynthetic regulation in immature and mature leaves. JOURNAL OF PLANT PHYSIOLOGY 2017; 209:76-83. [PMID: 28013173 DOI: 10.1016/j.jplph.2016.11.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 11/07/2016] [Accepted: 11/16/2016] [Indexed: 05/07/2023]
Abstract
Cyclic electron flow (CEF) around photosystem I (PSI) is essential for photosynthesis in mature leaves. However, the physiological roles of CEF in immature leaves are little known. Here, we measured the PSI and PSII activities, light response changes in PSI and PSII energy quenching for immature and mature leaves of Erythrophleum guineense grown under full sunlight. Comparing with the maximum quantum yield of PSII (Fv/Fm), the immature leaves had much lower values of the maximum photo-oxidizable P700 (Pm) than the mature leaves, suggesting the unsynchronized development of PSI and PSII activities. Furthermore, the immature leaves displayed significantly lower capacities for the photosynthetic electron flow through PSII (ETRII) and CEF. However, when exposed to high light, the immature leaves displayed higher levels of non-photochemical quenching (NPQ) and P700 oxidation ration [Y(ND)] than mature leaves. Under high light, the similar NPQ values were accompanied with much lower CEF activity in the immature leaves. These results suggest that, in immature leaves, CEF primarily contributes to photoprotection for PSI and PSII via acidification of thylakoid lumen. By comparison, in mature leaves, a large fraction of CEF-dependent generation of ΔpH contributes to ATP synthesis and a relative small proportion favors photoprotection via lumen acidification. These findings highlight the specific roles of CEF in photosynthetic regulation in immature and mature leaves.
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Affiliation(s)
- Wei Huang
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China; Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - Ying-Jie Yang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - Shi-Bao Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China.
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18
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Wang D, Fu A. The Plastid Terminal Oxidase is a Key Factor Balancing the Redox State of Thylakoid Membrane. Enzymes 2016; 40:143-171. [PMID: 27776780 DOI: 10.1016/bs.enz.2016.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
Mitochondria possess oxygen-consuming respiratory electron transfer chains (RETCs), and the oxygen-evolving photosynthetic electron transfer chain (PETC) resides in chloroplasts. Evolutionarily mitochondria and chloroplasts are derived from ancient α-proteobacteria and cyanobacteria, respectively. However, cyanobacteria harbor both RETC and PETC on their thylakoid membranes. It is proposed that chloroplasts could possess a RETC on the thylakoid membrane, in addition to PETC. Identification of a plastid terminal oxidase (PTOX) in the chloroplast from the Arabidopsis variegation mutant immutans (im) demonstrated the presence of a RETC in chloroplasts, and the PTOX is the committed oxidase. PTOX is distantly related to the mitochondrial alternative oxidase (AOX), which is responsible for the CN-insensitive alternative RETC. Similar to AOX, an ubiquinol (UQH2) oxidase, PTOX is a plastoquinol (PQH2) oxidase on the chloroplast thylakoid membrane. Lack of PTOX, Arabidopsis im showed a light-dependent variegation phenotype; and mutant plants will not survive the mediocre light intensity during its early development stage. PTOX is very important for carotenoid biosynthesis, since the phytoene desaturation, a key step in the carotenoid biosynthesis, is blocked in the white sectors of Arabidopsis im mutant. PTOX is found to be a stress-related protein in numerous research instances. It is generally believed that PTOX can protect plants from various environmental stresses, especially high light stress. PTOX also plays significant roles in chloroplast development and plant morphogenesis. Global physiological roles played by PTOX could be a direct or indirect consequence of its PQH2 oxidase activity to maintain the PQ pool redox state on the thylakoid membrane. The PTOX-dependent chloroplast RETC (so-called chlororespiration) does not contribute significantly when chloroplast PETC is normally developed and functions well. However, PTOX-mediated RETC could be the major force to regulate the PQ pool redox balance in the darkness, under conditions of stress, in nonphotosynthetic plastids, especially in the early development from proplastids to chloroplasts.
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Affiliation(s)
- D Wang
- The Key Laboratory of Western Resources Biology and Biological Technology, College of Life Sciences, Northwest University, Xian, China; Shaanxi Province Key Laboratory of Biotechnology, College of Life Sciences, Northwest University, Xian, China
| | - A Fu
- The Key Laboratory of Western Resources Biology and Biological Technology, College of Life Sciences, Northwest University, Xian, China; Shaanxi Province Key Laboratory of Biotechnology, College of Life Sciences, Northwest University, Xian, China.
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19
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Peterson RB, Schultes NP, McHale NA, Zelitch I. Evidence for a Role for NAD(P)H Dehydrogenase in Concentration of CO2 in the Bundle Sheath Cell of Zea mays. PLANT PHYSIOLOGY 2016; 171:125-38. [PMID: 27002061 PMCID: PMC4854706 DOI: 10.1104/pp.16.00120] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 03/21/2016] [Indexed: 05/05/2023]
Abstract
Prior studies with Nicotiana and Arabidopsis described failed assembly of the chloroplastic NDH [NAD(P)H dehydrogenase] supercomplex by serial mutation of several subunit genes. We examined the properties of Zea mays leaves containing Mu and Ds insertions into nuclear gene exons encoding the critical o- and n-subunits of NDH, respectively. In vivo reduction of plastoquinone in the dark was sharply diminished in maize homozygous mutant compared to normal leaves but not to the extreme degree observed for the corresponding lesions in Arabidopsis. The net carbon assimilation rate (A) at high irradiance and saturating CO2 levels was reduced by one-half due to NDH mutation in maize although no genotypic effect was evident at very low CO2 levels. Simultaneous assessment of chlorophyll fluorescence and A in maize at low (2% by volume) and high (21%) O2 levels indicated the presence of a small, yet detectable, O2-dependent component of total linear photosynthetic electron transport in 21% O2 This O2-dependent component decreased with increasing CO2 level indicative of photorespiration. Photorespiration was generally elevated in maize mutant compared to normal leaves. Quantification of the proportion of total electron transport supporting photorespiration enabled estimation of the bundle sheath cell CO2 concentration (Cb) using a simple kinetic model of ribulose bisphosphate carboxylase/oxygenase function. The A versus Cb relationships overlapped for normal and mutant lines consistent with occurrence of strictly CO2-limited photosynthesis in the mutant bundle sheath cell. The results are discussed in terms of a previously reported CO2 concentration model [Laisk A, Edwards GE (2000) Photosynth Res 66: 199-224].
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Affiliation(s)
- Richard B Peterson
- Scientist Emeritus (R.B.P., N.A.M., I.Z.), Department of Plant Pathology and Ecology (N.P.S.), The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511
| | - Neil P Schultes
- Scientist Emeritus (R.B.P., N.A.M., I.Z.), Department of Plant Pathology and Ecology (N.P.S.), The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511
| | - Neil A McHale
- Scientist Emeritus (R.B.P., N.A.M., I.Z.), Department of Plant Pathology and Ecology (N.P.S.), The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511
| | - Israel Zelitch
- Scientist Emeritus (R.B.P., N.A.M., I.Z.), Department of Plant Pathology and Ecology (N.P.S.), The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511
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20
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Antal TK, Krendeleva TE, Tyystjärvi E. Multiple regulatory mechanisms in the chloroplast of green algae: relation to hydrogen production. PHOTOSYNTHESIS RESEARCH 2015; 125:357-81. [PMID: 25986411 DOI: 10.1007/s11120-015-0157-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Accepted: 05/11/2015] [Indexed: 05/10/2023]
Abstract
A complex regulatory network in the chloroplast of green algae provides an efficient tool for maintenance of energy and redox balance in the cell under aerobic and anaerobic conditions. In this review, we discuss the structural and functional organizations of electron transport pathways in the chloroplast, and regulation of photosynthesis in the green microalga Chlamydomonas reinhardtii. The focus is on the regulatory mechanisms induced in response to nutrient deficiency stress and anoxia and especially on the role of a hydrogenase-mediated reaction in adaptation to highly reducing conditions and ATP deficiency in the cell.
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Affiliation(s)
- Taras K Antal
- Faculty of Biology, Moscow State University, Vorobyevi Gory, Moscow, 119992, Russia,
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21
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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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22
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Photoinduction of cyclosis-mediated interactions between distant chloroplasts. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:379-389. [PMID: 25615586 DOI: 10.1016/j.bbabio.2015.01.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 01/10/2015] [Accepted: 01/13/2015] [Indexed: 11/24/2022]
Abstract
Communications between chloroplasts and other organelles based on the exchange of metabolites, including redox active substances, are recognized as a part of intracellular regulation, chlororespiration, and defense against oxidative stress. Similar communications may operate between spatially distant chloroplasts in large cells where photosynthetic and respiratory activities are distributed unevenly under fluctuating patterned illumination. Microfluorometry of chlorophyll fluorescence in vivo in internodal cells of the alga Chara corallina revealed that a 30-s pulse of localized light induces a transient increase (~25%) in F' fluorescence of remote cell parts exposed to dim background light at a 1.5-mm distance on the downstream side from the illuminated spot in the plane of unilateral cytoplasmic streaming but has no effect on F' at equal distance on the upstream side. An abrupt arrest of cytoplasmic streaming for about 30s by triggering the action potential extended either the ascending or descending fronts of the F' fluorescence response, depending on the exact moment of streaming cessation. The response of F' fluorescence to localized illumination of a distant cell region was absent in dark-adapted internodes, when the localized light was applied within the first minute after switching on continuous background illumination of the whole cell, but it appeared in full after longer exposures to continuous background light. These results and the elimination of the F' response by methyl viologen known to redirect electron transport pathways beyond photosystem I indicate the importance of photosynthetic induction and the stromal redox state for long-distance communications of chloroplasts in vivo.
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23
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Abstract
In the last few years, advances in algal research have identified the participation of haemoglobins in nitrogen metabolism and the management of reactive nitrogen and oxygen species. This chapter summarises the state of knowledge concerning algal haemoglobins with a focus on the most widely used model system, namely, Chlamydomonas reinhardtii. Genetic, physiologic, structural, and chemical information is compiled to provide a framework for further studies.
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Affiliation(s)
- Eric A Johnson
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA
| | - Juliette T J Lecomte
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA.
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24
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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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25
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Mullineaux CW. Co-existence of photosynthetic and respiratory activities in cyanobacterial thylakoid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:503-11. [PMID: 24316145 DOI: 10.1016/j.bbabio.2013.11.017] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 11/15/2013] [Accepted: 11/24/2013] [Indexed: 01/10/2023]
Abstract
The thylakoid membranes of cyanobacteria are the major sites of respiratory electron transport as well as photosynthetic light reactions. The photosynthetic and respiratory electron transport chains share some components, and their presence in the same membrane opens up the possibility for a variety of "unorthodox" electron transport routes. Many of the theoretically possible electron transport pathways have indeed been detected in particular species and circumstances. Electron transport has a crucial impact on the redox balance of the cell and therefore the pathways of electron flow in the cyanobacterial thylakoid membrane must be tightly regulated. This review summarises what is known of cyanobacterial electron transport components, their interactions and their sub-cellular location. The role of thylakoid membrane organisation in controlling electron transport pathways is discussed with respect to recent evidence that the larger-scale distribution of complexes in the membrane is important for controlling electron exchange between the photosynthetic and respiratory complexes. The distribution of complexes on scales of 100nm or more is under physiological control, showing that larger-scale thylakoid membrane re-arrangement is a key factor in controlling the crosstalk between photosynthetic and respiratory electron transport. This article is part of a Special Issue entitled: Dynamic and ultrastructure of bioenergetic membranes and their components.
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Affiliation(s)
- Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
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26
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Silva J, Barrote I, Costa MM, Albano S, Santos R. Physiological responses of Zostera marina and Cymodocea nodosa to light-limitation stress. PLoS One 2013; 8:e81058. [PMID: 24312260 PMCID: PMC3842938 DOI: 10.1371/journal.pone.0081058] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Accepted: 10/18/2013] [Indexed: 11/29/2022] Open
Abstract
The effects of light-limitation stress were investigated in natural stands of the seagrasses Zostera marina and Cymodocea nodosa in Ria Formosa coastal lagoon, southern Portugal. Three levels of light attenuation were imposed for 3 weeks in two adjacent meadows (2-3 m depth), each dominated by one species. The response of photosynthesis to light was determined with oxygen electrodes. Chlorophylls and carotenoids were determined by high-pressure liquid chromatography (HPLC). Soluble protein, carbohydrates, malondialdehyde and phenol contents were also analysed. Both species showed evident signs of photoacclimation. Their maximum photosynthetic rates were significantly reduced with shading. Ratios between specific light harvesting carotenoids and the epoxidation state of xanthophyll cycle carotenoids revealed significantly higher light harvesting efficiency of C. nodosa, a competitive advantage in a low light environment. The contents of both soluble sugars and starch were considerably lower in Z. marina plants, particularly in the rhizomes, decreasing even further with shading. The different carbohydrate energy storage strategies found between the two species clearly favour C. nodosa's resilience to light deprivation, a condition enhanced by its intrinsic arrangement of the pigment pool. On the other hand, Z. marina revealed a lower tolerance to light reduction, mostly due to a less plastic arrangement of the pigment pool and lower carbohydrate storage. Our findings indicate that Z. marina is close to a light-mediated ecophysiological threshold in Ria Formosa.
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Affiliation(s)
- João Silva
- CCMAR - Centro de Ciências do Mar, Faro, Portugal
| | - Isabel Barrote
- CECTA - Centro de Estudos em Ciências e Tecnologias Agrárias, Universidade do Algarve, Faro, Portugal
| | | | | | - Rui Santos
- CCMAR - Centro de Ciências do Mar, Faro, Portugal
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27
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Xie X, Gu W, Gao S, Lu S, Li J, Pan G, Wang G, Shen S. Alternative electron transports participate in the maintenance of violaxanthin De-epoxidase activity of Ulva sp. under low irradiance. PLoS One 2013; 8:e78211. [PMID: 24250793 PMCID: PMC3826755 DOI: 10.1371/journal.pone.0078211] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 09/19/2013] [Indexed: 11/18/2022] Open
Abstract
The xanthophyll cycle (Xc), which involves violaxanthin de-epoxidase (VDE) and the zeaxanthin epoxidase (ZEP), is one of the most rapid and efficient responses of plant and algae to high irradiance. High light intensity can activate VDE to convert violaxanthin (Vx) to zeaxanthin (Zx) via antheraxanthin (Ax). However, it remains unclear whether VDE remains active under low light or dark conditions when there is no significant accumulation of Ax and Zx, and if so, how the ΔpH required for activation of VDE is built. In this study, we used salicylaldoxime (SA) to inhibit ZEP activity in the intertidal macro-algae Ulva sp. (Ulvales, Chlorophyta) and then characterized VDE under low light and dark conditions with various metabolic inhibitors. With inhibition of ZEP by SA, VDE remained active under low light and dark conditions, as indicated by large accumulations of Ax and Zx at the expense of Vx. When PSII-mediated linear electron transport systems were completely inhibited by SA and DCMU, alternative electron transport systems (i.e., cyclic electron transport and chlororespiration) could maintain VDE activity. Furthermore, accumulations of Ax and Zx decreased significantly when SA, DCMU, or DBMIB together with an inhibitor of chlororespiration (i.e., propyl gallate (PG)) were applied to Ulva sp. This result suggests that chlororespiration not only participates in the build-up of the necessary ΔpH, but that it also possibly influences VDE activity indirectly by diminishing the oxygen level in the chloroplast.
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Affiliation(s)
- Xiujun Xie
- Tianjin Key Laboratory of Marine Resources and Chemistry, College of Marine Science and Engineering, Tianjin University of Science and Technology, Tianjin, China
| | - Wenhui Gu
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Graduate School, Chinese Academy of Sciences, Beijing, China
| | - Shan Gao
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Graduate School, Chinese Academy of Sciences, Beijing, China
| | - Shan Lu
- School of Life Science, Nanjing University, Nanjing, China
| | - Jian Li
- Earth and Life Institute, Catholic University of Louvain, Louvain la Neuve, Belgium
| | - Guanghua Pan
- Tianjin Key Laboratory of Marine Resources and Chemistry, College of Marine Science and Engineering, Tianjin University of Science and Technology, Tianjin, China
| | - Guangce Wang
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Songdong Shen
- College of Life Sciences, Soochow University, Suzhou, China
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Bulychev AA, Alova AV, Bibikova TN. Strong alkalinization of Chara cell surface in the area of cell wall incision as an early event in mechanoperception. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2359-69. [DOI: 10.1016/j.bbamem.2013.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 06/21/2013] [Accepted: 07/01/2013] [Indexed: 12/20/2022]
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Antal TK, Kukarskikh GP, Bulychev AA, Tyystjärvi E, Krendeleva T. Antimycin A effect on the electron transport in chloroplasts of two Chlamydomonas reinhardtii strains. PLANTA 2013; 237:1241-1250. [PMID: 23354456 DOI: 10.1007/s00425-013-1843-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 01/07/2013] [Indexed: 06/01/2023]
Abstract
The effects of antimycin A on the redox state of plastoquinone and on electron donation to photosystem I (PS I) were studied in sulfur-deprived Chlamydomonas reinhardtii cells of the strains cc406 and 137c. We found that this reagent suppresses cyclic electron flow around PS I in the cc406 strain, whereas this inhibitory effect was completely absent in the 137c strain. In the latter strain, antimycin A induced rapid reduction of plastoquinone in the dark and considerably enhanced the rate of electron donation to P700 (+) in the dark. Importantly, neither myxothiazol, an inhibitor of mitochondrial respiration, FCCP, a protonophore, nor propyl gallate, an inhibitor of the plastid terminal oxidase, induced such a strong effect like antimycin A. The results indicate that in the chloroplast of the 137c strain, antimycin A has a site of action outside of the machinery of cyclic electron flow.
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Affiliation(s)
- Taras K Antal
- Biological Faculty, Moscow State University, Vorobyevi Gory, 119992, Moscow, Russia.
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Propagation of photoinduced signals with the cytoplasmic flow along Characean internodes: evidence from changes in chloroplast fluorescence and surface pH. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2013; 42:441-53. [DOI: 10.1007/s00249-013-0895-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 12/03/2012] [Accepted: 02/19/2013] [Indexed: 10/27/2022]
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Trouillard M, Shahbazi M, Moyet L, Rappaport F, Joliot P, Kuntz M, Finazzi G. Kinetic properties and physiological role of the plastoquinone terminal oxidase (PTOX) in a vascular plant. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:2140-8. [DOI: 10.1016/j.bbabio.2012.08.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 08/24/2012] [Accepted: 08/29/2012] [Indexed: 10/27/2022]
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Papazi A, Andronis E, Ioannidis NE, Chaniotakis N, Kotzabasis K. High yields of hydrogen production induced by meta-substituted dichlorophenols biodegradation from the green alga Scenedesmus obliquus. PLoS One 2012; 7:e49037. [PMID: 23145057 PMCID: PMC3492192 DOI: 10.1371/journal.pone.0049037] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Accepted: 10/03/2012] [Indexed: 01/16/2023] Open
Abstract
Hydrogen is a highly promising energy source with important social and economic implications. The ability of green algae to produce photosynthetic hydrogen under anaerobic conditions has been known for years. However, until today the yield of production has been very low, limiting an industrial scale use. In the present paper, 73 years after the first report on H(2)-production from green algae, we present a combinational biological system where the biodegradation procedure of one meta-substituted dichlorophenol (m-dcp) is the key element for maintaining continuous and high rate H(2)-production (>100 times higher than previously reported) in chloroplasts and mitochondria of the green alga Scenedesmus obliquus. In particular, we report that reduced m-dcps (biodegradation intermediates) mimic endogenous electron and proton carriers in chloroplasts and mitochondria, inhibit Photosystem II (PSII) activity (and therefore O(2) production) and enhance Photosystem I (PSI) and hydrogenase activity. In addition, we show that there are some indications for hydrogen production from sources other than chloroplasts in Scenedesmus obliquus. The regulation of these multistage and highly evolved redox pathways leads to high yields of hydrogen production and paves the way for an efficient application to industrial scale use, utilizing simple energy sources and one meta-substituted dichlorophenol as regulating elements.
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Affiliation(s)
- Aikaterini Papazi
- Department of Biology, University of Crete, Voutes University Campus, Heraklion, Crete, Greece
| | - Efthimios Andronis
- Department of Biology, University of Crete, Voutes University Campus, Heraklion, Crete, Greece
| | - Nikolaos E. Ioannidis
- Department of Biology, University of Crete, Voutes University Campus, Heraklion, Crete, Greece
| | - Nikolaos Chaniotakis
- Department of Chemistry, University of Crete, Voutes University Campus, Heraklion, Crete, Greece
| | - Kiriakos Kotzabasis
- Department of Biology, University of Crete, Voutes University Campus, Heraklion, Crete, Greece
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Bharati A, Kar M, Sabat SC. Artemisinin inhibits chloroplast electron transport activity: mode of action. PLoS One 2012; 7:e38942. [PMID: 22719995 PMCID: PMC3374801 DOI: 10.1371/journal.pone.0038942] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 05/14/2012] [Indexed: 11/18/2022] Open
Abstract
Artemisinin, a secondary metabolite produced in Artemisia plant species, besides having antimalarial properties is also phytotoxic. Although, the phytotoxic activity of the compound has been long recognized, no information is available on the mechanism of action of the compound on photosynthetic activity of the plant. In this report, we have evaluated the effect of artemisinin on photoelectron transport activity of chloroplast thylakoid membrane. The inhibitory effect of the compound, under in vitro condition, was pronounced in loosely and fully coupled thylakoids; being strong in the former. The extent of inhibition was drastically reduced in the presence of uncouplers like ammonium chloride or gramicidin; a characteristic feature described for energy transfer inhibitors. The compound, on the other hand, when applied to plants (in vivo), behaved as a potent inhibitor of photosynthetic electron transport. The major site of its action was identified to be the Q(B); the secondary quinone moiety of photosystemII complex. Analysis of photoreduction kinetics of para-benzoquinone and duroquinone suggest that the inhibition leads to formation of low pool of plastoquinol, which becomes limiting for electron flow through photosystemI. Further it was ascertained that the in vivo inhibitory effect appeared as a consequence of the formation of an unidentified artemisinin-metabolite rather than by the interaction of the compound per se. The putative metabolite of artemisinin is highly reactive in instituting the inhibition of photosynthetic electron flow eventually reducing the plant growth.
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Affiliation(s)
- Adyasha Bharati
- Gene Function and Regulation, Stress Biology Laboratory, Institute of Life Sciences, Bhubaneswar, Odisha, India
| | - Monaranjan Kar
- Department of Botany, Utkal University, Vani Vihar, Bhubaneswar, Odisha, India
| | - Surendra Chandra Sabat
- Gene Function and Regulation, Stress Biology Laboratory, Institute of Life Sciences, Bhubaneswar, Odisha, India
- * E-mail:
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Abstract
Reactive oxygen species (ROS) are astonishingly versatile molecular species and radicals that are poised at the core of a sophisticated network of signaling pathways of plants and act as core regulator of cell physiology and cellular responses to environment. ROS are continuously generated in plants as an inevitable consequence of redox cascades of aerobic metabolism. In one hand, plants are surfeited with the mechanism to combat reactive oxygen species, in other circumstances, plants appear to purposefully generate (oxidative burst) and exploit ROS or ROS-induced secondary breakdown products for the regulation of almost every aspect of plant biology, from perception of environmental cues to gene expression. The molecular language associated with ROS-mediated signal transduction, leading to modulation in gene expression to be one of the specific early stress response in the acclamatory performance of the plant. They may even act as “second messenger” modulating the activities of specific proteins or expression of genes by changing redox balance of the cell. The network of redox signals orchestrates metabolism for regulating energy production to utilization, interfering with primary signaling agents (hormones) to respond to changing environmental cues at every stage of plant development. The oxidative lipid peroxidation products and the resulting generated products thereof (associated with stress and senescence) also represent “biological signals,” which do not require preceding activation of genes. Unlike ROS-induced expression of genes, these lipid peroxidation products produce nonspecific response to a large variety of environmental stresses. The present review explores the specific and nonspecific signaling language of reactive oxygen species in plant acclamatory defense processes, controlled cell death, and development. Special emphasis is given to ROS and redox-regulated gene expression and the role of redox-sensitive proteins in signal transduction event. It also describes the emerging complexity of apparently contradictory roles that ROS play in cellular physiology to ascertain their position in the life of the plant.
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Kallas T. Cytochrome b 6 f Complex at the Heart of Energy Transduction and Redox Signaling. PHOTOSYNTHESIS 2012. [DOI: 10.1007/978-94-007-1579-0_21] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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36
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Cornic G, Baker NR. Electron Transport in Leaves: A Physiological Perspective. PHOTOSYNTHESIS 2012. [DOI: 10.1007/978-94-007-1579-0_23] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Wicke S, Schneeweiss GM, dePamphilis CW, Müller KF, Quandt D. The evolution of the plastid chromosome in land plants: gene content, gene order, gene function. PLANT MOLECULAR BIOLOGY 2011; 76:273-97. [PMID: 21424877 PMCID: PMC3104136 DOI: 10.1007/s11103-011-9762-4] [Citation(s) in RCA: 825] [Impact Index Per Article: 63.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2010] [Accepted: 02/19/2011] [Indexed: 05/18/2023]
Abstract
This review bridges functional and evolutionary aspects of plastid chromosome architecture in land plants and their putative ancestors. We provide an overview on the structure and composition of the plastid genome of land plants as well as the functions of its genes in an explicit phylogenetic and evolutionary context. We will discuss the architecture of land plant plastid chromosomes, including gene content and synteny across land plants. Moreover, we will explore the functions and roles of plastid encoded genes in metabolism and their evolutionary importance regarding gene retention and conservation. We suggest that the slow mode at which the plastome typically evolves is likely to be influenced by a combination of different molecular mechanisms. These include the organization of plastid genes in operons, the usually uniparental mode of plastid inheritance, the activity of highly effective repair mechanisms as well as the rarity of plastid fusion. Nevertheless, structurally rearranged plastomes can be found in several unrelated lineages (e.g. ferns, Pinaceae, multiple angiosperm families). Rearrangements and gene losses seem to correlate with an unusual mode of plastid transmission, abundance of repeats, or a heterotrophic lifestyle (parasites or myco-heterotrophs). While only a few functional gene gains and more frequent gene losses have been inferred for land plants, the plastid Ndh complex is one example of multiple independent gene losses and will be discussed in detail. Patterns of ndh-gene loss and functional analyses indicate that these losses are usually found in plant groups with a certain degree of heterotrophy, might rendering plastid encoded Ndh1 subunits dispensable.
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Affiliation(s)
- Susann Wicke
- Department of Biogeography and Botanical Garden, University of Vienna, Rennweg 14, 1030 Vienna, Austria.
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Rasulov B, Hüve K, Laisk A, Niinemets Ü. Induction of a longer term component of isoprene release in darkened aspen leaves: origin and regulation under different environmental conditions. PLANT PHYSIOLOGY 2011; 156:816-31. [PMID: 21502186 PMCID: PMC3177278 DOI: 10.1104/pp.111.176222] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 04/12/2011] [Indexed: 05/19/2023]
Abstract
After darkening, isoprene emission continues for 20 to 30 min following biphasic kinetics. The initial dark release of isoprene (postillumination emission), for 200 to 300 s, occurs mainly at the expense of its immediate substrate, dimethylallyldiphosphate (DMADP), but the origin and controls of the secondary burst of isoprene release (dark-induced emission) between approximately 300 and 1,500 s, are not entirely understood. We used a fast-response gas-exchange system to characterize the controls of dark-induced isoprene emission by light, temperature, and CO(2) and oxygen concentrations preceding leaf darkening and the effects of short light pulses and changing gas concentrations during dark-induced isoprene release in hybrid aspen (Populus tremula × Populus tremuloides). The effect of the 2-C-methyl-D-erythritol-4-phosphate pathway inhibitor fosmidomycin was also investigated. The integral of postillumination isoprene release was considered to constitute the DMADP pool size, while the integral of dark-induced emission was defined as the "dark" pool. Overall, the steady-state emission rate in light and the maximum dark-induced emission rate responded similarly to variations in preceding environmental drivers and atmospheric composition, increasing with increasing light, having maxima at approximately 40 °C and close to the CO(2) compensation point, and were suppressed by lack of oxygen. The DMADP and dark pool sizes were also similar through their environmental dependencies, except for high temperatures, where the dark pool significantly exceeded the DMADP pool. Isoprene release could be enhanced by short lightflecks early during dark-induced isoprene release, but not at later stages. Fosmidomycin strongly suppressed both the isoprene emission rates in light and in the dark, but the dark pool was only moderately affected. These results demonstrate a strong correspondence between the steady-state isoprene emission in light and the dark-induced emission and suggest that the dark pool reflects the total pool size of 2-C-methyl-d-erythritol-4-phosphate pathway metabolites upstream of DMADP. These metabolites are converted to isoprene as soon as ATP and NADPH become available, likely by dark activation of chloroplastic glycolysis and chlororespiration.
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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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Cruz S, Goss R, Wilhelm C, Leegood R, Horton P, Jakob T. Impact of chlororespiration on non-photochemical quenching of chlorophyll fluorescence and on the regulation of the diadinoxanthin cycle in the diatom Thalassiosira pseudonana. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:509-19. [PMID: 20876335 PMCID: PMC3003802 DOI: 10.1093/jxb/erq284] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 08/23/2010] [Accepted: 08/23/2010] [Indexed: 05/20/2023]
Abstract
In diatoms, metabolic activity during long dark periods leads to a chlororespiratory electron flow, which is accompanied by the build-up of a proton gradient strong enough to activate the diadinoxanthin (Ddx) de-epoxidation reaction of the Ddx cycle. In the present study, the impact of chlororespiration on non-photochemical quenching (NPQ) of chlorophyll fluorescence and the regulation of the Ddx cycle in the diatom Thalassiosira pseudonana was investigated by manipulation of the redox state of the photosynthetic electron transport chain during darkness. The response of a transfer of T. pseudonana cells from growth light conditions to 60 min darkness was found to depend on oxygen: in its presence there was no significant reduction of the PQ pool and no de-epoxidation of Ddx to diatoxanthin (Dtx). Under anaerobic conditions a high reduction state of the electron transport chain and a slow but steady de-epoxidation of Ddx was observed, which resulted in a significant accumulation of Dtx after 60 min of anaerobiosis. Unexpectedly, this high concentration of Dtx did not induce a correspondingly high NPQ as it would have been observed with Dtx formed under high light conditions. However, the sensitivity of NPQ to Dtx in cells kept under dark anaerobic conditions increased during reoxygenation and far-red (FR) light illumination. The results are discussed with respect to the activation of the de-epoxidation reaction and the formation of NPQ and their dependence on the extent of the proton gradient across the thylakoid membrane.
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Affiliation(s)
- Sonia Cruz
- Animal and Plant Sciences Department, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Reimund Goss
- Institute of Biology I, Plant Physiology, University of Leipzig, Johannisallee 21-23, D-04103 Leipzig, Germany
| | - Christian Wilhelm
- Institute of Biology I, Plant Physiology, University of Leipzig, Johannisallee 21-23, D-04103 Leipzig, Germany
| | - Richard Leegood
- Animal and Plant Sciences Department, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Peter Horton
- Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Torsten Jakob
- Institute of Biology I, Plant Physiology, University of Leipzig, Johannisallee 21-23, D-04103 Leipzig, Germany
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Membrane potential is involved in regulation of photosynthetic reactions in the marine diatom Thalassiosira weissflogii. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2010; 102:169-73. [PMID: 21131210 DOI: 10.1016/j.jphotobiol.2010.11.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Revised: 11/10/2010] [Accepted: 11/11/2010] [Indexed: 10/18/2022]
Abstract
High-intensity Chl fluorescence transients (OJIP transients) and light-induced kinetics of the delayed light emission were measured in diatom microalga Thalassiosira weissflogii in the presence of various uncouplers and photosynthetic inhibitors. The I step in the OJIP transients in T. weissflogii was essentially reduced or completely absent but was restored in the presence of uncouplers valinomycin, FCCP, and nigericin. Moreover, valinomycin enhanced ΔpH-dependent non-photochemical fluorescence quenching following the OJIP rise. In the presence of valinomycin, the transthylakoid membrane potential was significantly inhibited as evaluated by measurements of the delayed light emission. The results suggest a membrane potential control of the fluorescence yield in T. weissflogii. Possible mechanisms underlying the observed effects of uncouplers are discussed.
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42
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Antal TK, Krendeleva TE, Rubin AB. Acclimation of green algae to sulfur deficiency: underlying mechanisms and application for hydrogen production. Appl Microbiol Biotechnol 2010; 89:3-15. [DOI: 10.1007/s00253-010-2879-6] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Revised: 09/02/2010] [Accepted: 09/07/2010] [Indexed: 11/29/2022]
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Antal T, Mattila H, Hakala-Yatkin M, Tyystjärvi T, Tyystjärvi E. Acclimation of photosynthesis to nitrogen deficiency in Phaseolus vulgaris. PLANTA 2010; 232:887-98. [PMID: 20632184 DOI: 10.1007/s00425-010-1227-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 07/06/2010] [Indexed: 05/22/2023]
Abstract
Nitrogen deficiency diminishes consumption of photosynthates in anabolic metabolism. We studied adjustments of the photosynthetic machinery in nitrogen-deficient bean plants and found four phenomena. First, the number of chloroplasts per cell decreased. Chloroplasts of nitrogen starved leaves contained less pigments than those of control leaves, but the in vitro activities of light reactions did not change when measured on chlorophyll basis. Second, nitrogen deficiency induced cyclic electron transfer. The amounts of Rubisco and ferredoxin-NADP(+) reductase decreased in nitrogen starved plants. Low activities of these enzymes are expected to lead to increase in reduction of oxygen by photosystem I. However, diaminobenzidine staining did not reveal hydrogen peroxide production in nitrogen starved plants. Measurements of far-red-light-induced redox changes of the primary donor of photosystem I suggested that instead of producing oxygen radicals, nitrogen starved plants develop a high activity of cyclic electron transport that competes with oxygen for electrons. Nitrogen starvation led to decrease in photochemical quenching and increase in non-photochemical quenching, indicating that cyclic electron transport reduces the plastoquinone pool and acidifies the lumen. A third effect is redistribution of excitation energy between the photosystems in favor of photosystem I. Thus, thylakoids of nitrogen starved plants appeared to be locked in state 2, which further protects photosystem II by decreasing its absorption cross-section. As a fourth response, the proportion of non-Q(B)-reducing photosystem II reaction centers increased and the redox potential of the Q(B)/Q(B)(-) pair decreased by 25 mV in a fraction of photosystem II centers of nitrogen starved plants.
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Affiliation(s)
- Taras Antal
- Molecular Plant Biology, Department of Biochemistry and Food Chemistry, University of Turku, Turku, Finland
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Nashilevitz S, Melamed-Bessudo C, Izkovich Y, Rogachev I, Osorio S, Itkin M, Adato A, Pankratov I, Hirschberg J, Fernie AR, Wolf S, Usadel B, Levy AA, Rumeau D, Aharoni A. An orange ripening mutant links plastid NAD(P)H dehydrogenase complex activity to central and specialized metabolism during tomato fruit maturation. THE PLANT CELL 2010; 22:1977-97. [PMID: 20571113 PMCID: PMC2910969 DOI: 10.1105/tpc.110.074716] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2010] [Revised: 05/14/2010] [Accepted: 06/07/2010] [Indexed: 05/18/2023]
Abstract
In higher plants, the plastidial NADH dehydrogenase (Ndh) complex supports nonphotochemical electron fluxes from stromal electron donors to plastoquinones. Ndh functions in chloroplasts are not clearly established; however, its activity was linked to the prevention of the overreduction of stroma, especially under stress conditions. Here, we show by the characterization of Orr(Ds), a dominant transposon-tagged tomato (Solanum lycopersicum) mutant deficient in the NDH-M subunit, that this complex is also essential for the fruit ripening process. Alteration to the NDH complex in fruit changed the climacteric, ripening-associated metabolites and transcripts as well as fruit shelf life. Metabolic processes in chromoplasts of ripening tomato fruit were affected in Orr(Ds), as mutant fruit were yellow-orange and accumulated substantially less total carotenoids, mainly beta-carotene and lutein. The changes in carotenoids were largely influenced by environmental conditions and accompanied by modifications in levels of other fruit antioxidants, namely, flavonoids and tocopherols. In contrast with the pigmentation phenotype in mature mutant fruit, Orr(Ds) leaves and green fruits did not display a visible phenotype but exhibited reduced Ndh complex quantity and activity. This study therefore paves the way for further studies on the role of electron transport and redox reactions in the regulation of fruit ripening and its associated metabolism.
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Affiliation(s)
- Shai Nashilevitz
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
- Faculty of Agricultural, Food, and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | | | - Yinon Izkovich
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ilana Rogachev
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Sonia Osorio
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Maxim Itkin
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Avital Adato
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ilya Pankratov
- Department of Genetics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Joseph Hirschberg
- Department of Genetics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Alisdair R. Fernie
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Shmuel Wolf
- Faculty of Agricultural, Food, and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Björn Usadel
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Avraham A. Levy
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Dominique Rumeau
- Commissariat à l'Energie Atomique Cadarache, Direction des Sciences du Vivant, Institut de Biologie Environnementale et Biotechnologie, Service de Biologie Végétale et de Microbiologie Environnementale, Laboratoire d'Ecophysiologie Moléculaire des Plantes, Unité Mixte de Recherche 6191, Centre National de la Recherche Scientifique/Commissariat à l'Energie Atomique/Université de la Méditerranée, F-13108 Saint-Paul-lez-Durance, France
| | - Asaph Aharoni
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
- Address correspondence to
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Agarwal R, Matros A, Melzer M, Mock HP, Sainis JK. Heterogeneity in thylakoid membrane proteome of Synechocystis 6803. J Proteomics 2010; 73:976-91. [DOI: 10.1016/j.jprot.2009.12.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 11/25/2009] [Accepted: 12/19/2009] [Indexed: 10/20/2022]
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Hohmann-Marriott MF, Takizawa K, Eaton-Rye JJ, Mets L, Minagawa J. The redox state of the plastoquinone pool directly modulates minimum chlorophyll fluorescence yield in Chlamydomonas reinhardtii. FEBS Lett 2010; 584:1021-6. [PMID: 20122933 DOI: 10.1016/j.febslet.2010.01.052] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 01/14/2010] [Accepted: 01/25/2010] [Indexed: 11/26/2022]
Abstract
The effect of the plastoquionone (PQ) pool oxidation state on minimum chlorophyll fluorescence was studied in the green alga Chlamydomonas reinhardtii. In wild type and a mutant strain that lacks both photosystems but retains light harvesting complexes, oxygen depletion induced a rise in minimum chlorophyll fluorescence. An increase in minimum fluorescence yield is also observed when the PQ pool becomes reduced in the presence of oxygen and after application of an ionophore that collapses the transmembrane proton gradient. Together these results indicate that minimum chlorophyll fluorescence is modulated by the PQ oxidation state.
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Livingston AK, Cruz JA, Kohzuma K, Dhingra A, Kramer DM. An Arabidopsis mutant with high cyclic electron flow around photosystem I (hcef) involving the NADPH dehydrogenase complex. THE PLANT CELL 2010; 22:221-33. [PMID: 20081115 PMCID: PMC2828696 DOI: 10.1105/tpc.109.071084] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 12/02/2009] [Accepted: 12/23/2009] [Indexed: 05/18/2023]
Abstract
Cyclic electron flow (CEFI) has been proposed to balance the chloroplast energy budget, but the pathway, mechanism, and physiological role remain unclear. We isolated a new class of mutant in Arabidopsis thaliana, hcef for high CEF1, which shows constitutively elevated CEF1. The first of these, hcef1, was mapped to chloroplast fructose-1,6-bisphosphatase. Crossing hcef1 with pgr5, which is deficient in the antimycin A-sensitive pathway for plastoquinone reduction, resulted in a double mutant that maintained the high CEF1 phenotype, implying that the PGR5-dependent pathway is not involved. By contrast, crossing hcef1 with crr2-2, deficient in thylakoid NADPH dehydrogenase (NDH) complex, results in a double mutant that is highly light sensitive and lacks elevated CEF1, suggesting that NDH plays a direct role in catalyzing or regulating CEF1. Additionally, the NdhI component of the NDH complex was highly expressed in hcef1, whereas other photosynthetic complexes, as well as PGR5, decreased. We propose that (1) NDH is specifically upregulated in hcef1, allowing for increased CEF1; (2) the hcef1 mutation imposes an elevated ATP demand that may trigger CEF1; and (3) alternative mechanisms for augmenting ATP cannot compensate for the loss of CEF1 through NDH.
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Affiliation(s)
- Aaron K. Livingston
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340
| | - Jeffrey A. Cruz
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340
| | - Kaori Kohzuma
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340
| | - Amit Dhingra
- Horticulture and Landscape Architecture, Washington State University, Pullman, Washington 99164-6340
| | - David M. Kramer
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340
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Ishida S, Takabayashi A, Ishikawa N, Hano Y, Endo T, Sato F. A novel nuclear-encoded protein, NDH-dependent cyclic electron flow 5, is essential for the accumulation of chloroplast NAD(P)H dehydrogenase complexes. PLANT & CELL PHYSIOLOGY 2009; 50:383-393. [PMID: 19122188 DOI: 10.1093/pcp/pcn205] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The chloroplast NAD(P)H dehydrogenase (NDH) complex, which reduces plastoquinones in thylakoid membranes, is involved in PSI cyclic electron flow and chlororespiration. In addition to land plants, the NDH complex is conserved in cyanobacteria. In this study, we identified a novel NDH-related gene of Arabidopsis, NDH-dependent cyclic electron flow 5 (NDF5, At1g55370). Post-illumination increases in chlorophyll fluorescence were absent in ndf5 mutant plants, which indicated that NDF5 is essential for NDH activity. Sequence analysis did not reveal any known functional motifs in NDF5, but there was some homology in amino acid sequence between NDF5 and NDF2, a known NDH subunit. NDF5 and NDF2 homologs were present in higher plants, but not cyanobacteria. A single homolog, which had similarity to both NDF5 and NDF2, was identified in the moss Physcomitrella patens. Immunoblot analysis showed that NDF5 localizes to membrane fractions of chloroplasts. The stability of NdhH, a subunit of the NDH complex, as well as NDF5 and NDF2, was decreased in ndf5, ndf2 and double ndf2/ndf5 mutants, resulting in a loss of NDH activity in these mutants. These results indicated that both NDF5 and NDF2 have essential functions in the stabilization of the NDH complex. We propose that NDF5 and NDF2 were acquired by land plants during evolution, and that in higher plants both NDF5 and NDF2 are critical to regulate NDH activity and each other's protein stability, as well as the stability of additional NDH subunits.
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Häusler RE, Geimer S, Kunz HH, Schmitz J, Dörmann P, Bell K, Hetfeld S, Guballa A, Flügge UI. Chlororespiration and grana hyperstacking: how an Arabidopsis double mutant can survive despite defects in starch biosynthesis and daily carbon export from chloroplasts. PLANT PHYSIOLOGY 2009; 149:515-33. [PMID: 18978072 PMCID: PMC2613729 DOI: 10.1104/pp.108.128124] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Accepted: 10/26/2008] [Indexed: 05/20/2023]
Abstract
An Arabidopsis (Arabidopsis thaliana) double mutant impaired in starch biosynthesis and the triose phosphate/phosphate translocator (adg1-1/tpt-1) is characterized by a diminished utilization of photoassimilates and the concomitant consumption of reducing power and energy produced in the photosynthetic light reaction. In order to guarantee survival, the double mutant responds to this metabolic challenge with growth retardation, an 80% decline in photosynthetic electron transport, diminished chlorophyll contents, an enhanced reduction state of plastoquinone in the dark (up to 50%), a perturbation of the redox poise in leaves (increased NADPH/NADP ratios and decreased ascorbate/dehydroascorbate ratios), hyperstacking of grana thylakoids, and an increased number of plastoglobules. Enhanced oxygen consumption and applications of inhibitors of alternative mitochondrial and chloroplast oxidases (AOX and PTOX) suggest that chlororespiration as well as mitochondrial respiration are involved in the enhanced plastoquinone reduction state in the dark. Transcript amounts of PTOX and AOX were diminished and nucleus-encoded components related to plastidic NADH reductase (NDH1) were increased in adg1-1/tpt-1 compared with the wild type. Cytochrome b559, proposed to be involved in the reoxidation of photosystem II, was not regulated at the transcriptional level. The hyperstacking of grana thylakoids mimics adaptation to low light, and increased plastoglobule numbers suggest a response to enhanced oxidative stress. Altered chloroplast organization combined with perturbations in the redox poise suggests that adg1-1/tpt-1 could be a tool for the in vivo study of retrograde signaling mechanisms controlling the coordinated expression of nucleus- and plastome-encoded photosynthetic genes.
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Affiliation(s)
- Rainer E Häusler
- Universität zu Köln, Botanisches Institut, D-50931 Cologne, Germany.
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Ishikawa N, Endo T, Sato F. Electron transport activities of Arabidopsis thaliana mutants with impaired chloroplastic NAD(P)H dehydrogenase. JOURNAL OF PLANT RESEARCH 2008; 121:521-526. [PMID: 18683022 DOI: 10.1007/s10265-008-0180-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Accepted: 06/16/2008] [Indexed: 05/26/2023]
Abstract
The activities of electron transport are compared between wild-type Arabidopsis and two Arabidopsis mutants deficient for the chloroplastic NAD(P)H dehydrogenase (NDH) which catalyzes cyclic electron transport around photosystem I. The quantum yield of photosystem II and the degree of non-photochemical quenching of chlorophyll fluorescence were of similar levels in the two NDH-deficient mutants and the wild type under non-stressed standard growth conditions. Stromal over-reduction was induced in Arabidopsis NDH mutants with high light treatment, as is the case in tobacco NDH mutants. However, unlike tobacco mutants, photoinhibition was not observed in the Arabidopsis NDH mutants.
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Affiliation(s)
- Noriko Ishikawa
- Department of Plant Genes and Totipotency, Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan
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