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Milrad Y, Mosebach L, Buchert F. Regulation of Microalgal Photosynthetic Electron Transfer. PLANTS (BASEL, SWITZERLAND) 2024; 13:2103. [PMID: 39124221 PMCID: PMC11314055 DOI: 10.3390/plants13152103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 07/24/2024] [Accepted: 07/26/2024] [Indexed: 08/12/2024]
Abstract
The global ecosystem relies on the metabolism of photosynthetic organisms, featuring the ability to harness light as an energy source. The most successful type of photosynthesis utilizes a virtually inexhaustible electron pool from water, but the driver of this oxidation, sunlight, varies on time and intensity scales of several orders of magnitude. Such rapid and steep changes in energy availability are potentially devastating for biological systems. To enable a safe and efficient light-harnessing process, photosynthetic organisms tune their light capturing, the redox connections between core complexes and auxiliary electron mediators, ion passages across the membrane, and functional coupling of energy transducing organelles. Here, microalgal species are the most diverse group, featuring both unique environmental adjustment strategies and ubiquitous protective mechanisms. In this review, we explore a selection of regulatory processes of the microalgal photosynthetic apparatus supporting smooth electron flow in variable environments.
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Affiliation(s)
- Yuval Milrad
- Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 8, 48143 Münster, Germany
| | - Laura Mosebach
- Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 8, 48143 Münster, Germany
| | - Felix Buchert
- Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 8, 48143 Münster, Germany
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2
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Savoie M, Mattison A, Genge L, Nadeau J, Śliwińska-Wilczewska S, Berthold M, Omar NM, Prášil O, Cockshutt AM, Campbell DA. Prochlorococcus marinus responses to light and oxygen. PLoS One 2024; 19:e0307549. [PMID: 39038009 PMCID: PMC11262661 DOI: 10.1371/journal.pone.0307549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Accepted: 07/08/2024] [Indexed: 07/24/2024] Open
Abstract
Prochlorococcus marinus, the smallest picocyanobacterium, comprises multiple clades occupying distinct niches, currently across tropical and sub-tropical oligotrophic ocean regions, including Oxygen Minimum Zones. Ocean warming may open growth-permissive temperatures in new, poleward photic regimes, along with expanded Oxygen Minimum Zones. We used ocean metaproteomic data on current Prochlorococcus marinus niches, to guide testing of Prochlorococcus marinus growth across a matrix of peak irradiances, photoperiods, spectral bands and dissolved oxygen. MED4 from Clade HLI requires greater than 4 h photoperiod, grows at 25 μmol O2 L-1 and above, and exploits high cumulative diel photon doses. MED4, however, relies upon an alternative oxidase to balance electron transport, which may exclude it from growth under our lowest, 2.5 μmol O2 L-1, condition. SS120 from clade LLII/III is restricted to low light under full 250 μmol O2 L-1, shows expanded light exploitation under 25 μmol O2 L-1, but is excluded from growth under 2.5 μmol O2 L-1. Intermediate oxygen suppresses the cost of PSII photoinactivation, and possibly the enzymatic production of H2O2 in SS120, which has limitations on genomic capacity for PSII and DNA repair. MIT9313 from Clade LLIV is restricted to low blue irradiance under 250 μmol O2 L-1, but exploits much higher irradiance under red light, or under lower O2 concentrations, conditions which slow photoinactivation of PSII and production of reactive oxygen species. In warming oceans, range expansions and competition among clades will be governed not only by light levels. Short photoperiods governed by latitude, temperate winters, and depth attenuation of light, will exclude clade HLI (including MED4) from some habitats. In contrast, clade LLII/III (including SS120), and particularly clade LLIV (including MIT9313), may exploit higher light niches nearer the surface, under expanding OMZ conditions, where low O2 relieves the stresses of oxidation stress and PSII photoinhibition.
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Affiliation(s)
- Mireille Savoie
- Department of Biology, Mount Allison University, Sackville, New Brunswick, Canada
| | - Aurora Mattison
- Department of Chemistry and Biochemistry, Mount Allison University, Sackville, New Brunswick, Canada
- Department of Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Laurel Genge
- Department of Biology, Mount Allison University, Sackville, New Brunswick, Canada
- Fisheries and Oceans Canada, Ecosystems Management Branch, Dartmouth, Nova Scotia, Canada
| | - Julie Nadeau
- Department of Biology, Mount Allison University, Sackville, New Brunswick, Canada
| | - Sylwia Śliwińska-Wilczewska
- Department of Biology, Mount Allison University, Sackville, New Brunswick, Canada
- Institute of Oceanography, University of Gdansk, Gdynia, Poland
| | - Maximilian Berthold
- Department of Biology, Mount Allison University, Sackville, New Brunswick, Canada
| | - Naaman M. Omar
- Department of Biology, Mount Allison University, Sackville, New Brunswick, Canada
| | - Ondřej Prášil
- Department of Biology, Mount Allison University, Sackville, New Brunswick, Canada
- Laboratory of Photosynthesis, Institute of Microbiology, Center Algatech, Trebon, Czech Republic
| | - Amanda M. Cockshutt
- Department of Chemistry and Biochemistry, Mount Allison University, Sackville, New Brunswick, Canada
- Department of Chemistry, St. Frances Xavier University, Antigonish, Nova Scotia, Canada
| | - Douglas A. Campbell
- Department of Biology, Mount Allison University, Sackville, New Brunswick, Canada
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3
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Elanskaya IV, Bulychev AA, Lukashev EP, Muronets EM, Maksimov EG. Roles of ApcD and orange carotenoid protein in photoinduction of electron transport upon dark-light transition in the Synechocystis PCC 6803 mutant deficient in flavodiiron protein Flv1. PHOTOSYNTHESIS RESEARCH 2024; 159:97-114. [PMID: 37093504 DOI: 10.1007/s11120-023-01019-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 04/13/2023] [Indexed: 05/03/2023]
Abstract
Flavodiiron proteins Flv1/Flv3 accept electrons from photosystem (PS) I. In this work we investigated light adaptation mechanisms of Flv1-deficient mutant of Synechocystis PCC 6803, incapable to form the Flv1/Flv3 heterodimer. First seconds of dark-light transition were studied by parallel measurements of light-induced changes in chlorophyll fluorescence, P700 redox transformations, fluorescence emission at 77 K, and OCP-dependent fluorescence quenching. During the period of Calvin cycle activation upon dark-light transition, the linear electron transport (LET) in wild type is supported by the Flv1/Flv3 heterodimer, whereas in Δflv1 mutant activation of LET upon illumination is preceded by cyclic electron flow that maintains State 2. The State 2-State 1 transition and Orange Carotenoid Protein (OCP)-dependent non-photochemical quenching occur independently of each other, begin in about 10 s after the illumination of the cells and are accompanied by a short-term re-reduction of the PSI reaction center (P700+). ApcD is important for the State 2-State 1 transition in the Δflv1 mutant, but S-M rise in chlorophyll fluorescence was not completely inhibited in Δflv1/ΔapcD mutant. LET in Δflv1 mutant starts earlier than the S-M rise in chlorophyll fluorescence, and the oxidation of plastoquinol (PQH2) pool promotes the activation of PSII, transient re-reduction of P700+ and transition to State 1. An attempt to induce state transition in the wild type under high intensity light using methyl viologen, highly oxidizing P700 and PQH2, was unsuccessful, showing that oxidation of intersystem electron-transport carriers might be insufficient for the induction of State 2-State 1 transition in wild type of Synechocystis under high light.
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Affiliation(s)
- Irina V Elanskaya
- Department of Genetics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Alexander A Bulychev
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Evgeny P Lukashev
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Elena M Muronets
- Department of Genetics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Eugene G Maksimov
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
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Piel T, Sandrini G, Weenink EFJ, Qin H, Herk MJV, Morales-Grooters ML, Schuurmans JM, Slot PC, Wijn G, Arntz J, Zervou SK, Kaloudis T, Hiskia A, Huisman J, Visser PM. Shifts in phytoplankton and zooplankton communities in three cyanobacteria-dominated lakes after treatment with hydrogen peroxide. HARMFUL ALGAE 2024; 133:102585. [PMID: 38485435 DOI: 10.1016/j.hal.2024.102585] [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: 10/03/2023] [Revised: 12/22/2023] [Accepted: 01/18/2024] [Indexed: 03/19/2024]
Abstract
Cyanobacteria can reach high densities in eutrophic lakes, which may cause problems due to their potential toxin production. Several methods are in use to prevent, control or mitigate harmful cyanobacterial blooms. Treatment of blooms with low concentrations of hydrogen peroxide (H2O2) is a promising emergency method. However, effects of H2O2 on cyanobacteria, eukaryotic phytoplankton and zooplankton have mainly been studied in controlled cultures and mesocosm experiments, while much less is known about the effectiveness and potential side effects of H2O2 treatments on entire lake ecosystems. In this study, we report on three different lakes in the Netherlands that were treated with average H2O2 concentrations ranging from 2 to 5 mg L-1 to suppress cyanobacterial blooms. Effects on phytoplankton and zooplankton communities, on cyanotoxin concentrations, and on nutrient availability in the lakes were assessed. After every H2O2 treatment, cyanobacteria drastically declined, sometimes by more than 99%, although blooms of Dolichospermum sp., Aphanizomenon sp., and Planktothrix rubescens were more strongly suppressed than a Planktothrix agardhii bloom. Eukaryotic phytoplankton were not significantly affected by the H2O2 additions and had an initial advantage over cyanobacteria after the treatment, when ample nutrients and light were available. In all three lakes, a new cyanobacterial bloom developed within several weeks after the first H2O2 treatment, and in two lakes a second H2O2 treatment was therefore applied to again suppress the cyanobacterial population. Rotifers strongly declined after most H2O2 treatments except when the H2O2 concentration was ≤ 2 mg L-1, whereas cladocerans were only mildly affected and copepods were least impacted by the added H2O2. In response to the treatments, the cyanotoxins microcystins and anabaenopeptins were released from the cells into the water column, but disappeared after a few days. We conclude that lake treatments with low concentrations of H2O2 can be a successful tool to suppress harmful cyanobacterial blooms, but may negatively affect some of the zooplankton taxa in lakes. We advise pre-tests prior to the treatment of lakes to define optimal treatment concentrations that kill the majority of the cyanobacteria and to minimize potential side effects on non-target organisms. In some cases, the pre-tests may discourage treatment of the lake.
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Affiliation(s)
- Tim Piel
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240,1090 GE Amsterdam, The Netherlands; Agendia NV, 1043 NT Amsterdam, The Netherlands
| | - Giovanni Sandrini
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240,1090 GE Amsterdam, The Netherlands; Department of Technology & Sources, Evides Water Company, 3006 AL Rotterdam, The Netherlands
| | - Erik F J Weenink
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240,1090 GE Amsterdam, The Netherlands
| | - Hongjie Qin
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240,1090 GE Amsterdam, The Netherlands; Guangdong Provincial Key Lab of Ornamental Plant Germplasm Innovation and Utilization, Environmental Horticulture Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Maria J van Herk
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240,1090 GE Amsterdam, The Netherlands
| | - Mariël Léon Morales-Grooters
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240,1090 GE Amsterdam, The Netherlands; Department of Biomedical Engineering, Erasmus MC University Rotterdam, Office Ee2302, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands
| | - J Merijn Schuurmans
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240,1090 GE Amsterdam, The Netherlands
| | - Pieter C Slot
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240,1090 GE Amsterdam, The Netherlands
| | - Geert Wijn
- Arcadis Nederland B.V., P.O. Box 264, 6800 AG Arnhem, The Netherlands
| | - Jasper Arntz
- Arcadis Nederland B.V., P.O. Box 264, 6800 AG Arnhem, The Netherlands
| | - Sevasti-Kiriaki Zervou
- Photo-Catalytic Processes and Environmental Chemistry, Institute of Nanoscience and Nanotechnology, National Centre for Scientific Research, "Demokritos", Patriarchou Gregoriou E & 27 Neapoleos Str, 15341 Athens, Greece
| | - Triantafyllos Kaloudis
- Photo-Catalytic Processes and Environmental Chemistry, Institute of Nanoscience and Nanotechnology, National Centre for Scientific Research, "Demokritos", Patriarchou Gregoriou E & 27 Neapoleos Str, 15341 Athens, Greece; Laboratory of Organic Micropollutants, Water Quality Control Department, Athens Water Supply & Sewerage Company (EYDAP SA), Athens, Greece
| | - Anastasia Hiskia
- Photo-Catalytic Processes and Environmental Chemistry, Institute of Nanoscience and Nanotechnology, National Centre for Scientific Research, "Demokritos", Patriarchou Gregoriou E & 27 Neapoleos Str, 15341 Athens, Greece
| | - Jef Huisman
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240,1090 GE Amsterdam, The Netherlands
| | - Petra M Visser
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240,1090 GE Amsterdam, The Netherlands
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Qin H, Sandrini G, Piel T, Slot PC, Huisman J, Visser PM. The harmful cyanobacterium Microcystis aeruginosa PCC7806 is more resistant to hydrogen peroxide at elevated CO 2. HARMFUL ALGAE 2023; 128:102482. [PMID: 37714576 DOI: 10.1016/j.hal.2023.102482] [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: 03/01/2023] [Revised: 07/28/2023] [Accepted: 07/28/2023] [Indexed: 09/17/2023]
Abstract
Rising atmospheric CO2 can intensify harmful cyanobacterial blooms in eutrophic lakes. Worldwide, these blooms are an increasing environmental concern. Low concentrations of hydrogen peroxide (H2O2) have been proposed as a short-term but eco-friendly approach to selectively mitigate cyanobacterial blooms. However, sensitivity of cyanobacteria to H2O2 can vary depending on the available resources. To find out how cyanobacteria respond to H2O2 under elevated CO2, Microcystis aeruginosa PCC 7806 was cultured in chemostats with nutrient-replete medium under C-limiting and C-replete conditions (150 ppm and 1500 ppm CO2, respectively). Microcystis chemostats exposed to high CO2 showed higher cell densities, biovolumes, and microcystin contents, but a lower photosynthetic efficiency and pH compared to the cultures grown under low CO2. Subsamples of the chemostats were treated with different concentrations of H2O2 (0-10 mg·L-1 H2O2) in batch cultures under two different light intensities (15 and 100 μmol photons m-2·s-1) and the response in photosynthetic vitality was monitored during 24 h. Results showed that Microcystis was more resistant to H2O2 at elevated CO2 than under carbon-limited conditions. Both low and high CO2-adapted cells were more sensitive to H2O2 at high light than at low light. Microcystins (MCs) leaked out of the cells of cultures exposed to 2-10 mg·L-1 H2O2, while the sum of intra- and extracellular MCs decreased. Although both H2O2 and CO2 concentrations in lakes vary in response to many factors, these results imply that it may become more difficult to suppress cyanobacterial blooms in eutrophic lakes when atmospheric CO2 concentrations continue to rise.
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Affiliation(s)
- Hongjie Qin
- Guangdong Provincial Key Lab of Ornamental Plant Germplasm Innovation and Utilization, Environmental Horticulture Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China; Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, The Netherlands; Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Giovanni Sandrini
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, The Netherlands; Department of Technology & Sources, Evides Water Company, Rotterdam, The Netherlands
| | - Tim Piel
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, The Netherlands
| | - Pieter C Slot
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, The Netherlands
| | - Jef Huisman
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, The Netherlands
| | - Petra M Visser
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, The Netherlands.
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6
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Bag P, Shutova T, Shevela D, Lihavainen J, Nanda S, Ivanov AG, Messinger J, Jansson S. Flavodiiron-mediated O 2 photoreduction at photosystem I acceptor-side provides photoprotection to conifer thylakoids in early spring. Nat Commun 2023; 14:3210. [PMID: 37270605 DOI: 10.1038/s41467-023-38938-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 05/23/2023] [Indexed: 06/05/2023] Open
Abstract
Green organisms evolve oxygen (O2) via photosynthesis and consume it by respiration. Generally, net O2 consumption only becomes dominant when photosynthesis is suppressed at night. Here, we show that green thylakoid membranes of Scots pine (Pinus sylvestris L) and Norway spruce (Picea abies) needles display strong O2 consumption even in the presence of light when extremely low temperatures coincide with high solar irradiation during early spring (ES). By employing different electron transport chain inhibitors, we show that this unusual light-induced O2 consumption occurs around photosystem (PS) I and correlates with higher abundance of flavodiiron (Flv) A protein in ES thylakoids. With P700 absorption changes, we demonstrate that electron scavenging from the acceptor-side of PSI via O2 photoreduction is a major alternative pathway in ES. This photoprotection mechanism in vascular plants indicates that conifers have developed an adaptative evolution trajectory for growing in harsh environments.
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Affiliation(s)
- Pushan Bag
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
- Section of Molecular Plant Biology, Department of Biology, University of Oxford, Oxford, UK
| | - Tatyana Shutova
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Dmitry Shevela
- Department of Chemistry, Chemical Biological Centre, Umeå University, Umeå, Sweden
| | - Jenna Lihavainen
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Sanchali Nanda
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Alexander G Ivanov
- Department of Biology, University of Western Ontario, London, ON, Canada
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Johannes Messinger
- Department of Chemistry, Chemical Biological Centre, Umeå University, Umeå, Sweden
- Department of Chemistry-Ångström laboratory, Uppsala University, Uppsala, Sweden
| | - Stefan Jansson
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden.
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Zhou Q, Yamamoto H, Shikanai T. Distinct contribution of two cyclic electron transport pathways to P700 oxidation. PLANT PHYSIOLOGY 2023; 192:326-341. [PMID: 36477622 PMCID: PMC10152692 DOI: 10.1093/plphys/kiac557] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 11/09/2022] [Accepted: 11/10/2022] [Indexed: 05/03/2023]
Abstract
Cyclic electron transport (CET) around Photosystem I (PSI) acidifies the thylakoid lumen and downregulates electron transport at the cytochrome b6f complex. This photosynthetic control is essential for oxidizing special pair chlorophylls (P700) of PSI for PSI photoprotection. In addition, CET depending on the PROTON GRADIENT REGULATION 5 (PGR5) protein oxidizes P700 by moving a pool of electrons from the acceptor side of PSI to the plastoquinone pool. This model of the acceptor-side regulation was proposed on the basis of the phenotype of the Arabidopsis (Arabidopsis thaliana) pgr5-1 mutant expressing Chlamydomonas (Chlamydomonas reinhardtii) plastid terminal oxidase (CrPTOX2). In this study, we extended the research including the Arabidopsis chlororespiratory reduction 2-2 (crr2-2) mutant defective in another CET pathway depending on the chloroplast NADH dehydrogenase-like (NDH) complex. Although the introduction of CrPTOX2 did not complement the defect in the acceptor-side regulation by PGR5, the function of the NDH complex was complemented except for its reverse reaction during the induction of photosynthesis. We evaluated the impact of CrPTOX2 under fluctuating light intensity in the wild-type, pgr5-1 and crr2-2 backgrounds. In the high-light period, both PGR5- and NDH-dependent CET were involved in the induction of photosynthetic control, whereas PGR5-dependent CET preferentially contributed to the acceptor-side regulation. On the contrary, the NDH complex probably contributed to the acceptor-side regulation in the low-light period but not in the high-light period. We evaluated the sensitivity of PSI to fluctuating light and clarified that acceptor-side regulation was necessary for PSI photoprotection by oxidizing P700 under high light.
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Affiliation(s)
- Qi Zhou
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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8
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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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9
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Santos-Merino M, Yun L, Ducat DC. Cyanobacteria as cell factories for the photosynthetic production of sucrose. Front Microbiol 2023; 14:1126032. [PMID: 36865782 PMCID: PMC9971976 DOI: 10.3389/fmicb.2023.1126032] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 01/24/2023] [Indexed: 02/16/2023] Open
Abstract
Biofuels and other biologically manufactured sustainable goods are growing in popularity and demand. Carbohydrate feedstocks required for industrial fermentation processes have traditionally been supplied by plant biomass, but the large quantities required to produce replacement commodity products may prevent the long-term feasibility of this approach without alternative strategies to produce sugar feedstocks. Cyanobacteria are under consideration as potential candidates for sustainable production of carbohydrate feedstocks, with potentially lower land and water requirements relative to plants. Several cyanobacterial strains have been genetically engineered to export significant quantities of sugars, especially sucrose. Sucrose is not only naturally synthesized and accumulated by cyanobacteria as a compatible solute to tolerate high salt environments, but also an easily fermentable disaccharide used by many heterotrophic bacteria as a carbon source. In this review, we provide a comprehensive summary of the current knowledge of the endogenous cyanobacterial sucrose synthesis and degradation pathways. We also summarize genetic modifications that have been found to increase sucrose production and secretion. Finally, we consider the current state of synthetic microbial consortia that rely on sugar-secreting cyanobacterial strains, which are co-cultivated alongside heterotrophic microbes able to directly convert the sugars into higher-value compounds (e.g., polyhydroxybutyrates, 3-hydroxypropionic acid, or dyes) in a single-pot reaction. We summarize recent advances reported in such cyanobacteria/heterotroph co-cultivation strategies and provide a perspective on future developments that are likely required to realize their bioindustrial potential.
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Affiliation(s)
- María Santos-Merino
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
| | - Lisa Yun
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
| | - Daniel C. Ducat
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
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10
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Burnap RL. Cyanobacterial Bioenergetics in Relation to Cellular Growth and Productivity. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2023; 183:25-64. [PMID: 36764956 DOI: 10.1007/10_2022_215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Cyanobacteria, the evolutionary originators of oxygenic photosynthesis, have the capability to convert CO2, water, and minerals into biomass using solar energy. This process is driven by intricate bioenergetic mechanisms that consist of interconnected photosynthetic and respiratory electron transport chains coupled. Over the last few decades, advances in physiochemical analysis, molecular genetics, and structural analysis have enabled us to gain a more comprehensive understanding of cyanobacterial bioenergetics. This includes the molecular understanding of the primary energy conversion mechanisms as well as photoprotective and other dissipative mechanisms that prevent photodamage when the rates of photosynthetic output, primarily in the form of ATP and NADPH, exceed the rates that cellular assimilatory processes consume these photosynthetic outputs. Despite this progress, there is still much to learn about the systems integration and the regulatory circuits that control expression levels for optimal cellular abundance and activity of the photosynthetic complexes and the cellular components that convert their products into biomass. With an improved understanding of these regulatory principles and mechanisms, it should be possible to optimally modify cyanobacteria for enhanced biotechnological purposes.
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Affiliation(s)
- Robert L Burnap
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA.
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11
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Santana‐Sánchez A, Nikkanen L, Werner E, Tóth G, Ermakova M, Kosourov S, Walter J, He M, Aro E, Allahverdiyeva Y. Flv3A facilitates O 2 photoreduction and affects H 2 photoproduction independently of Flv1A in diazotrophic Anabaena filaments. THE NEW PHYTOLOGIST 2023; 237:126-139. [PMID: 36128660 PMCID: PMC10092803 DOI: 10.1111/nph.18506] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 09/10/2022] [Indexed: 05/23/2023]
Abstract
The model heterocyst-forming filamentous cyanobacterium Anabaena sp. PCC 7120 (Anabaena) is a typical example of a multicellular organism capable of simultaneously performing oxygenic photosynthesis in vegetative cells and O2 -sensitive N2 -fixation inside heterocysts. The flavodiiron proteins have been shown to participate in photoprotection of photosynthesis by driving excess electrons to O2 (a Mehler-like reaction). Here, we performed a phenotypic and biophysical characterization of Anabaena mutants impaired in vegetative-specific Flv1A and Flv3A in order to address their physiological relevance in the bioenergetic processes occurring in diazotrophic Anabaena under variable CO2 conditions. We demonstrate that both Flv1A and Flv3A are required for proper induction of the Mehler-like reaction upon a sudden increase in light intensity, which is likely important for the activation of carbon-concentrating mechanisms and CO2 fixation. Under ambient CO2 diazotrophic conditions, Flv3A is responsible for moderate O2 photoreduction, independently of Flv1A, but only in the presence of Flv2 and Flv4. Strikingly, the lack of Flv3A resulted in strong downregulation of the heterocyst-specific uptake hydrogenase, which led to enhanced H2 photoproduction under both oxic and micro-oxic conditions. These results reveal a novel regulatory network between the Mehler-like reaction and the diazotrophic metabolism, which is of great interest for future biotechnological applications.
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Affiliation(s)
- Anita Santana‐Sánchez
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Lauri Nikkanen
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Elisa Werner
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Gábor Tóth
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Maria Ermakova
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Sergey Kosourov
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Julia Walter
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Meilin He
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Eva‐Mari Aro
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
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12
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Shaffique S, Khan MA, Wani SH, Pande A, Imran M, Kang SM, Rahim W, Khan SA, Bhatta D, Kwon EH, Lee IJ. A Review on the Role of Endophytes and Plant Growth Promoting Rhizobacteria in Mitigating Heat Stress in Plants. Microorganisms 2022; 10:microorganisms10071286. [PMID: 35889005 PMCID: PMC9319882 DOI: 10.3390/microorganisms10071286] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 02/04/2023] Open
Abstract
Among abiotic stresses, heat stress is described as one of the major limiting factors of crop growth worldwide, as high temperatures elicit a series of physiological, molecular, and biochemical cascade events that ultimately result in reduced crop yield. There is growing interest among researchers in the use of beneficial microorganisms. Intricate and highly complex interactions between plants and microbes result in the alleviation of heat stress. Plant–microbe interactions are mediated by the production of phytohormones, siderophores, gene expression, osmolytes, and volatile compounds in plants. Their interaction improves antioxidant activity and accumulation of compatible osmolytes such as proline, glycine betaine, soluble sugar, and trehalose, and enriches the nutrient status of stressed plants. Therefore, this review aims to discuss the heat response of plants and to understand the mechanisms of microbe-mediated stress alleviation on a physio-molecular basis. This review indicates that microbes have a great potential to enhance the protection of plants from heat stress and enhance plant growth and yield. Owing to the metabolic diversity of microorganisms, they can be useful in mitigating heat stress in crop plants. In this regard, microorganisms do not present new threats to ecological systems. Overall, it is expected that continued research on microbe-mediated heat stress tolerance in plants will enable this technology to be used as an ecofriendly tool for sustainable agronomy.
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Affiliation(s)
- Shifa Shaffique
- Department of Applied Biosciences, Kyungpook National University, Daegu 41566, Korea; (S.S.); (M.A.K.); (M.I.); (S.-M.K.); (D.B.); (E.-H.K.)
| | - Muhammad Aaqil Khan
- Department of Applied Biosciences, Kyungpook National University, Daegu 41566, Korea; (S.S.); (M.A.K.); (M.I.); (S.-M.K.); (D.B.); (E.-H.K.)
| | - Shabir Hussain Wani
- Mountain Research Center for Field Crops Khudwani, Shere-e-Kashmir University of Agriculture Sciences and Technology Srinagar, Anantnag 190025, Jammu and Kashmir, India;
| | - Anjali Pande
- Laboratory of Plant Molecular Pathology and Functional Genomics, Department of Plant Biosciences, School of Applied Biosciences, College of Agriculture and Life Science, Kyungpook National University, Daegu 41944, Korea; (A.P.); (W.R.)
| | - Muhammad Imran
- Department of Applied Biosciences, Kyungpook National University, Daegu 41566, Korea; (S.S.); (M.A.K.); (M.I.); (S.-M.K.); (D.B.); (E.-H.K.)
| | - Sang-Mo Kang
- Department of Applied Biosciences, Kyungpook National University, Daegu 41566, Korea; (S.S.); (M.A.K.); (M.I.); (S.-M.K.); (D.B.); (E.-H.K.)
| | - Waqas Rahim
- Laboratory of Plant Molecular Pathology and Functional Genomics, Department of Plant Biosciences, School of Applied Biosciences, College of Agriculture and Life Science, Kyungpook National University, Daegu 41944, Korea; (A.P.); (W.R.)
| | - Sumera Afzal Khan
- Centre of Biotechnology and Microbiology, University of Peshawar, Peshawar 45000, Pakistan;
| | - Dibya Bhatta
- Department of Applied Biosciences, Kyungpook National University, Daegu 41566, Korea; (S.S.); (M.A.K.); (M.I.); (S.-M.K.); (D.B.); (E.-H.K.)
| | - Eun-Hae Kwon
- Department of Applied Biosciences, Kyungpook National University, Daegu 41566, Korea; (S.S.); (M.A.K.); (M.I.); (S.-M.K.); (D.B.); (E.-H.K.)
| | - In-Jung Lee
- Department of Applied Biosciences, Kyungpook National University, Daegu 41566, Korea; (S.S.); (M.A.K.); (M.I.); (S.-M.K.); (D.B.); (E.-H.K.)
- Correspondence: ; Tel.: +82-53-950-5708
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13
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Smolinski SL, Lubner CE, Guo Z, Artz JH, Brown KA, Mulder DW, King PW. The influence of electron utilization pathways on photosystem I photochemistry in Synechocystis sp. PCC 6803. RSC Adv 2022; 12:14655-14664. [PMID: 35702219 PMCID: PMC9109680 DOI: 10.1039/d2ra01295b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 05/06/2022] [Indexed: 01/24/2023] Open
Abstract
The capacity of cyanobacteria to adapt to highly dynamic photon flux and nutrient availability conditions results from controlled management and use of reducing power, and is a major contributing factor to the efficiency of photosynthesis in aquatic environments. The response to changing conditions includes modulating gene expression and protein-protein interactions that serve to adjust the use of electron flux and mechanisms that control photosynthetic electron transport (PET). In this regard, the photochemical activity of photosystem I (PSI) reaction centers can support balancing of cyclic (CEF) and linear electron flow (LEF), and the coupling of redox carriers for use by electron utilization pathways. Therefore, changes in the utilization of reducing power might be expected to result in compensating changes at PSI as a means to support balance of electron flux. To understand this functional relationship, we investigated the properties of PSI and its photochemical activity in cells that lack flavodiiron 1 catalyzed oxygen reduction activity (ORR1). In the absence of ORR1, the oxygen evolution and consumption rates declined together with a shift in the oligomeric form of PSI towards monomers. The effect of these changes on PSI energy and electron transfer properties was examined in isolated trimer and monomer fractions of PSI reaction centers. Collectively, the results demonstrate that PSI photochemistry is modulated through coordination with the depletion of electron demand in the absence of ORR1.
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Affiliation(s)
- Sharon L. Smolinski
- National Renewable Energy Laboratory15013 Denver West ParkwayGoldenCO80401USA
| | - Carolyn E. Lubner
- National Renewable Energy Laboratory15013 Denver West ParkwayGoldenCO80401USA
| | - Zhanjun Guo
- National Renewable Energy Laboratory15013 Denver West ParkwayGoldenCO80401USA
| | - Jacob H. Artz
- National Renewable Energy Laboratory15013 Denver West ParkwayGoldenCO80401USA
| | - Katherine A. Brown
- National Renewable Energy Laboratory15013 Denver West ParkwayGoldenCO80401USA
| | - David W. Mulder
- National Renewable Energy Laboratory15013 Denver West ParkwayGoldenCO80401USA
| | - Paul W. King
- National Renewable Energy Laboratory15013 Denver West ParkwayGoldenCO80401USA
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14
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Basso L, Sakoda K, Kobayashi R, Yamori W, Shikanai T. Flavodiiron proteins enhance the rate of CO2 assimilation in Arabidopsis under fluctuating light intensity. PLANT PHYSIOLOGY 2022; 189:375-387. [PMID: 35171289 PMCID: PMC9070813 DOI: 10.1093/plphys/kiac064] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 01/24/2022] [Indexed: 05/19/2023]
Abstract
The proton concentration gradient (ΔpH) and membrane potential (Δψ) formed across the thylakoid membrane contribute to ATP synthesis in chloroplasts. Additionally, ΔpH downregulates photosynthetic electron transport via the acidification of the thylakoid lumen. K+ exchange antiporter 3 (KEA3) relaxes this downregulation by substituting ΔpH with Δψ in response to fluctuation of light intensity. In the Arabidopsis (Arabidopsis thaliana) line overexpressing KEA3 (KEA3ox), the rate of electron transport is elevated by accelerating the relaxation of ΔpH after a shift from high light (HL) to low light. However, the plant cannot control electron transport toward photosystem I (PSI), resulting in PSI photodamage. In this study, we crossed the KEA3ox line with the line (Flavodiiron [Flv]) expressing the Flv proteins of Physcomitrium patens. In the double transgenic line (Flv-KEA3ox), electrons overloading toward PSI were pumped out by Flv proteins. Consequently, photodamage of PSI was alleviated to the wild-type level. The rate of CO2 fixation was enhanced in Flv and Flv-KEA3ox lines during HL periods of fluctuating light, although CO2 fixation was unaffected in any transgenic lines in constant HL. Upregulation of CO2 fixation was accompanied by elevated stomatal conductance in fluctuating light. Consistent with the results of gas exchange experiments, the growth of Flv and Flv-KEA3ox plants was better than that of WT and KEA3ox plants under fluctuating light.
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Affiliation(s)
- Leonardo Basso
- Department of Botany, Graduate School of Science, Kyoto
University, Kyoto, 606-8502, Japan
| | - Kazuma Sakoda
- Institute for Sustainable Agro-Ecosystem Services, Graduate School of
Agriculture and Life Science, University of Tokyo, Tokyo, 188-0002,
Japan
- Japan Society for the Promotion of Science, Tokyo, Japan
| | - Ryouhei Kobayashi
- Department of Botany, Graduate School of Science, Kyoto
University, Kyoto, 606-8502, Japan
| | - Wataru Yamori
- Institute for Sustainable Agro-Ecosystem Services, Graduate School of
Agriculture and Life Science, University of Tokyo, Tokyo, 188-0002,
Japan
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15
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Suganami M, Konno S, Maruhashi R, Takagi D, Tazoe Y, Wada S, Yamamoto H, Shikanai T, Ishida H, Suzuki Y, Makino A. Expression of flavodiiron protein rescues defects in electron transport around PSI resulting from overproduction of Rubisco activase in rice. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2589-2600. [PMID: 35134146 DOI: 10.1093/jxb/erac035] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 02/01/2022] [Indexed: 06/14/2023]
Abstract
Fragility of photosystem I has been observed in transgenic rice plants that overproduce Rubisco activase (RCA). In this study, we examined the effects of RCA overproduction on the sensitivity of PSI to photoinhibition in three lines of plants overexpressing RCA (RCA-ox). In all the RCA-ox plants the quantum yield of PSI [Y(I)] decreased whilst in contrast the quantum yield of acceptor-side limitation of PSI [Y(NA)] increased, especially under low light conditions. In the transgenic line with the highest RCA content (RCA-ox 1), the quantum yield of PSII [Y(II)] and CO2 assimilation also decreased under low light. When leaves were exposed to high light (2000 μmol photon m-2 s-1) for 60 min, the maximal activity of PSI (Pm) drastically decreased in RCA-ox 1. These results suggested that overproduction of RCA disturbs PSI electron transport control, thus increasing the susceptibility of PSI to photoinhibition. When flavodiiron protein (FLV), which functions as a large electron sink downstream of PSI, was expressed in the RCA-ox 1 background (RCA-FLV), PSI and PSII parameters, and CO2 assimilation were recovered to wild-type levels. Thus, expression of FLV restored the robustness of PSI in RCA-ox plants.
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Affiliation(s)
- Mao Suganami
- Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai 980-8572, Japan
| | - So Konno
- Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai 980-8572, Japan
| | - Ryo Maruhashi
- Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai 980-8572, Japan
| | - Daisuke Takagi
- Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai 980-8572, Japan
| | - Youshi Tazoe
- Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai 980-8572, Japan
| | - Shinya Wada
- Graduate School of Agricultural Science, Kobe University, Nada-ku, Kobe 657-8501, Japan
| | - Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Hiroyuki Ishida
- Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai 980-8572, Japan
| | - Yuji Suzuki
- Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Amane Makino
- Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai 980-8572, Japan
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16
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Theodosiou E, Tüllinghoff A, Toepel J, Bühler B. Exploitation of Hetero- and Phototrophic Metabolic Modules for Redox-Intensive Whole-Cell Biocatalysis. Front Bioeng Biotechnol 2022; 10:855715. [PMID: 35497353 PMCID: PMC9043136 DOI: 10.3389/fbioe.2022.855715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 03/09/2022] [Indexed: 11/13/2022] Open
Abstract
The successful realization of a sustainable manufacturing bioprocess and the maximization of its production potential and capacity are the main concerns of a bioprocess engineer. A main step towards this endeavor is the development of an efficient biocatalyst. Isolated enzyme(s), microbial cells, or (immobilized) formulations thereof can serve as biocatalysts. Living cells feature, beside active enzymes, metabolic modules that can be exploited to support energy-dependent and multi-step enzyme-catalyzed reactions. Metabolism can sustainably supply necessary cofactors or cosubstrates at the expense of readily available and cheap resources, rendering external addition of costly cosubstrates unnecessary. However, for the development of an efficient whole-cell biocatalyst, in depth comprehension of metabolic modules and their interconnection with cell growth, maintenance, and product formation is indispensable. In order to maximize the flux through biosynthetic reactions and pathways to an industrially relevant product and respective key performance indices (i.e., titer, yield, and productivity), existing metabolic modules can be redesigned and/or novel artificial ones established. This review focuses on whole-cell bioconversions that are coupled to heterotrophic or phototrophic metabolism and discusses metabolic engineering efforts aiming at 1) increasing regeneration and supply of redox equivalents, such as NAD(P/H), 2) blocking competing fluxes, and 3) increasing the availability of metabolites serving as (co)substrates of desired biosynthetic routes.
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Affiliation(s)
- Eleni Theodosiou
- Institute of Applied Biosciences, Centre for Research and Technology Hellas, Thessaloniki, Greece
| | - Adrian Tüllinghoff
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH—UFZ, Leipzig, Germany
| | - Jörg Toepel
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH—UFZ, Leipzig, Germany
| | - Bruno Bühler
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH—UFZ, Leipzig, Germany
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17
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Heterologous Lactate Synthesis in Synechocystis sp. Strain PCC 6803 Causes a Growth Condition-Dependent Carbon Sink Effect. Appl Environ Microbiol 2022; 88:e0006322. [PMID: 35369703 PMCID: PMC9040622 DOI: 10.1128/aem.00063-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Cyanobacteria are considered promising hosts for product synthesis directly from CO2 via photosynthetic carbon assimilation. The introduction of heterologous carbon sinks in terms of product synthesis has been reported to induce the so-called “carbon sink effect,” described as the release of unused photosynthetic capacity by the introduction of additional carbon. This effect is thought to arise from a limitation of carbon metabolism that represents a bottleneck in carbon and electron flow, thus enforcing a downregulation of photosynthetic efficiency. It is not known so far how the cellular source/sink balance under different growth conditions influences the extent of the carbon sink effect and in turn product formation from CO2, constituting a heterologous carbon sink. We compared the Synechocystis sp. strain PCC 6803 wild type (WT) with an engineered lactate-producing strain (SAA023) in defined metabolic states. Unexpectedly, high-light conditions combined with carbon limitation enabled additional carbon assimilation for lactate production without affecting biomass formation. Thus, a strong carbon sink effect only was observed under carbon and thus sink limitation, but not under high-sink conditions. We show that the carbon sink effect was accompanied by an increased rate of alternative electron flow (AEF). Thus, AEF plays a crucial role in the equilibration of source/sink imbalances, presumably via ATP/NADPH balancing. This study emphasizes that the evaluation of the biotechnological potential of cyanobacteria profits from cultivation approaches enabling the establishment of defined metabolic states and respective quantitative analytics. Factors stimulating photosynthesis and carbon fixation are discussed. IMPORTANCE Previous studies reported various and differing effects of the heterologous production of carbon-based molecules on photosynthetic and growth efficiency of cyanobacteria. The typically applied cultivation in batch mode, with continuously changing growth conditions, however, precludes a clear differentiation between the impact of cultivation conditions on cell physiology and effects related to the specific nature of the product and its synthesis pathway. In this study, we employed a continuous cultivation system to maintain defined source/sink conditions and thus metabolic states. This allowed a systematic and quantitative analysis of the effect of NADPH-consuming lactate production on photosynthetic and growth efficiency. This approach enables a realistic evaluation of the biotechnological potential of engineered cyanobacterial strains. For example, the quantum requirement for carbon production was found to constitute an excellent indicator of the source/sink balance and thus a key parameter for photobioprocess optimization. Such knowledge is fundamental for rational and efficient strain and process development.
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18
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The Oxygen Paradigm—Quantitative Impact of High Concentrations of Dissolved Oxygen on Kinetics and Large-Scale Production of Arthrospira platensis. CHEMENGINEERING 2022. [DOI: 10.3390/chemengineering6010014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The cultivation of Arthrospira platensis in tubular photobioreactors (tPBRs) presents a promising approach for the commercial production of nutraceuticals and food products as it can achieve high productivity and effective process control. In closed photobioreactors, however, high amounts of photosynthetically produced oxygen can accumulate. So far, there has been a wide range of discussion on how dissolved oxygen concentrations (DOCs) affect bioprocess kinetics, and the subject has mainly been assessed empirically. In this study, we used photorespirometry to quantify the impact of DOCs on the growth kinetics and phycocyanin content of the widely cultivated cyanobacterium A. platensis. The photorespirometric routine revealed that the illumination intensity and cell dry weight concentration are important interconnected process parameters behind the impact that DOCs have on the bioprocess kinetics. Unfavorable process conditions such as low biomass concentrations or high illumination intensities yielded significant growth inhibition and reduced the phycocyanin content of A. platensis by up to 35%. In order to predict the biomass productivity of the large-scale cultivation of A. platensis in tPBRs, a simple process model was extended to include photoautotrophic oxygen production and accumulation in the tPBR to evaluate the performance of two configurations of a 5000 L tPBR.
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19
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Walter J, Kromdijk J. Here comes the sun: How optimization of photosynthetic light reactions can boost crop yields. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:564-591. [PMID: 34962073 PMCID: PMC9302994 DOI: 10.1111/jipb.13206] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/22/2021] [Indexed: 05/22/2023]
Abstract
Photosynthesis started to evolve some 3.5 billion years ago CO2 is the substrate for photosynthesis and in the past 200-250 years, atmospheric levels have approximately doubled due to human industrial activities. However, this time span is not sufficient for adaptation mechanisms of photosynthesis to be evolutionarily manifested. Steep increases in human population, shortage of arable land and food, and climate change call for actions, now. Thanks to substantial research efforts and advances in the last century, basic knowledge of photosynthetic and primary metabolic processes can now be translated into strategies to optimize photosynthesis to its full potential in order to improve crop yields and food supply for the future. Many different approaches have been proposed in recent years, some of which have already proven successful in different crop species. Here, we summarize recent advances on modifications of the complex network of photosynthetic light reactions. These are the starting point of all biomass production and supply the energy equivalents necessary for downstream processes as well as the oxygen we breathe.
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Affiliation(s)
- Julia Walter
- Department of Plant SciencesUniversity of CambridgeCambridgeCB2 3EAUK
| | - Johannes Kromdijk
- Department of Plant SciencesUniversity of CambridgeCambridgeCB2 3EAUK
- Carl R Woese Institute for Genomic BiologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinois61801USA
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20
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Shimakawa G, Shoguchi E, Burlacot A, Ifuku K, Che Y, Kumazawa M, Tanaka K, Nakanishi S. Coral symbionts evolved a functional polycistronic flavodiiron gene. PHOTOSYNTHESIS RESEARCH 2022; 151:113-124. [PMID: 34309771 DOI: 10.1007/s11120-021-00867-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 07/17/2021] [Indexed: 05/26/2023]
Abstract
Photosynthesis in cyanobacteria, green algae, and basal land plants is protected against excess reducing pressure on the photosynthetic chain by flavodiiron proteins (FLV) that dissipate photosynthetic electrons by reducing O2. In these organisms, the genes encoding FLV are always conserved in the form of a pair of two-type isozymes (FLVA and FLVB) that are believed to function in O2 photo-reduction as a heterodimer. While coral symbionts (dinoflagellates of the family Symbiodiniaceae) are the only algae to harbor FLV in photosynthetic red plastid lineage, only one gene is found in transcriptomes and its role and activity remain unknown. Here, we characterized the FLV genes in Symbiodiniaceae and found that its coding region is composed of tandemly repeated FLV sequences. By measuring the O2-dependent electron flow and P700 oxidation, we suggest that this atypical FLV is active in vivo. Based on the amino-acid sequence alignment and the phylogenetic analysis, we conclude that in coral symbionts, the gene pair for FLVA and FLVB have been fused to construct one coding region for a hybrid enzyme, which presumably occurred when or after both genes were inherited from basal green algae to the dinoflagellate. Immunodetection suggested the FLV polypeptide to be cleaved by a post-translational mechanism, adding it to the rare cases of polycistronic genes in eukaryotes. Our results demonstrate that FLV are active in coral symbionts with genomic arrangement that is unique to these species. The implication of these unique features on their symbiotic living environment is discussed.
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Affiliation(s)
- Ginga Shimakawa
- Research Center for Solar Energy Chemistry, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531, Japan.
| | - Eiichi Shoguchi
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, 904-0495, Japan
| | - Adrien Burlacot
- Aix Marseille University, CEA, CNRS, Institut de Biosciences Et Biotechnologies Aix-Marseille, CEA Cadarache, 13108, Saint Paul-Lez-Durance, France
- Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, 111 Koshland Hall, Berkeley, CA, 94720-3102, USA
| | - Kentaro Ifuku
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
| | - Yufen Che
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
| | - Minoru Kumazawa
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Sakyo, Kyoto, 606-8502, Japan
| | - Kenya Tanaka
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8631, Japan
| | - Shuji Nakanishi
- Research Center for Solar Energy Chemistry, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531, Japan
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8631, Japan
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21
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Ilíková I, Ilík P, Opatíková M, Arshad R, Nosek L, Karlický V, Kučerová Z, Roudnický P, Pospíšil P, Lazár D, Bartoš J, Kouřil R. Towards spruce-type photosystem II: consequences of the loss of light-harvesting proteins LHCB3 and LHCB6 in Arabidopsis. PLANT PHYSIOLOGY 2021; 187:2691-2715. [PMID: 34618099 PMCID: PMC8644234 DOI: 10.1093/plphys/kiab396] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 07/26/2021] [Indexed: 05/28/2023]
Abstract
The largest stable photosystem II (PSII) supercomplex in land plants (C2S2M2) consists of a core complex dimer (C2), two strongly (S2) and two moderately (M2) bound light-harvesting protein (LHCB) trimers attached to C2 via monomeric antenna proteins LHCB4-6. Recently, we have shown that LHCB3 and LHCB6, presumably essential for land plants, are missing in Norway spruce (Picea abies), which results in a unique structure of its C2S2M2 supercomplex. Here, we performed structure-function characterization of PSII supercomplexes in Arabidopsis (Arabidopsis thaliana) mutants lhcb3, lhcb6, and lhcb3 lhcb6 to examine the possibility of the formation of the "spruce-type" PSII supercomplex in angiosperms. Unlike in spruce, in Arabidopsis both LHCB3 and LHCB6 are necessary for stable binding of the M trimer to PSII core. The "spruce-type" PSII supercomplex was observed with low abundance only in the lhcb3 plants and its formation did not require the presence of LHCB4.3, the only LHCB4-type protein in spruce. Electron microscopy analysis of grana membranes revealed that the majority of PSII in lhcb6 and namely in lhcb3 lhcb6 mutants were arranged into C2S2 semi-crystalline arrays, some of which appeared to structurally restrict plastoquinone diffusion. Mutants without LHCB6 were characterized by fast induction of non-photochemical quenching and, on the contrary to the previous lhcb6 study, by only transient slowdown of electron transport between PSII and PSI. We hypothesize that these functional changes, associated with the arrangement of PSII into C2S2 arrays in thylakoids, may be important for the photoprotection of both PSI and PSII upon abrupt high-light exposure.
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Affiliation(s)
- Iva Ilíková
- Institute of Experimental Botany of the Czech Academy of Sciences, Centre of
the Region Haná for Biotechnological and Agricultural Research, 783 71
Olomouc, Czech Republic
| | - Petr Ilík
- Department of Biophysics, Centre of the Region Haná for Biotechnological and
Agricultural Research, Palacký University, 783 71 Olomouc, Czech Republic
| | - Monika Opatíková
- Department of Biophysics, Centre of the Region Haná for Biotechnological and
Agricultural Research, Palacký University, 783 71 Olomouc, Czech Republic
| | - Rameez Arshad
- Department of Biophysics, Centre of the Region Haná for Biotechnological and
Agricultural Research, Palacký University, 783 71 Olomouc, Czech Republic
- Electron Microscopy Group, Groningen Biomolecular Sciences and Biotechnology
Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen,
The Netherlands
| | - Lukáš Nosek
- Department of Biophysics, Centre of the Region Haná for Biotechnological and
Agricultural Research, Palacký University, 783 71 Olomouc, Czech Republic
| | - Václav Karlický
- Department of Physics, Faculty of Science, University of Ostrava,
710 00 Ostrava, Czech Republic
- Global Change Research Institute of the Czech Academy of
Sciences, 603 00 Brno, Czech Republic
| | - Zuzana Kučerová
- Department of Biophysics, Centre of the Region Haná for Biotechnological and
Agricultural Research, Palacký University, 783 71 Olomouc, Czech Republic
| | - Pavel Roudnický
- Central European Institute of Technology, Masaryk University, 625
00 Brno, Czech Republic
| | - Pavel Pospíšil
- Department of Biophysics, Centre of the Region Haná for Biotechnological and
Agricultural Research, Palacký University, 783 71 Olomouc, Czech Republic
| | - Dušan Lazár
- Department of Biophysics, Centre of the Region Haná for Biotechnological and
Agricultural Research, Palacký University, 783 71 Olomouc, Czech Republic
| | - Jan Bartoš
- Institute of Experimental Botany of the Czech Academy of Sciences, Centre of
the Region Haná for Biotechnological and Agricultural Research, 783 71
Olomouc, Czech Republic
| | - Roman Kouřil
- Department of Biophysics, Centre of the Region Haná for Biotechnological and
Agricultural Research, Palacký University, 783 71 Olomouc, Czech Republic
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Improved photosynthetic capacity and photosystem I oxidation via heterologous metabolism engineering in cyanobacteria. Proc Natl Acad Sci U S A 2021; 118:2021523118. [PMID: 33836593 PMCID: PMC7980454 DOI: 10.1073/pnas.2021523118] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Cyanobacteria have been increasingly explored as a biotechnological platform, although their economic feasibility relies in part on the capacity to maximize their photosynthetic, solar-to-biomass energy conversion efficiency. Here we show that cyanobacterial photosynthetic capacity can be increased by diverting cellular resources toward heterologous, energy-storing metabolic pathways and by reducing electron flow to photoprotective, but energy-dissipating, oxygen reduction reactions. We further show that these heterologous sinks can partially contribute to photosystem I (PSI) oxidation, suggesting an engineering strategy to improve both energy storage capacity and robustness by selective diversion of excess photosynthetic capacity to productive processes. Cyanobacteria must prevent imbalances between absorbed light energy (source) and the metabolic capacity (sink) to utilize it to protect their photosynthetic apparatus against damage. A number of photoprotective mechanisms assist in dissipating excess absorbed energy, including respiratory terminal oxidases and flavodiiron proteins, but inherently reduce photosynthetic efficiency. Recently, it has been hypothesized that some engineered metabolic pathways may improve photosynthetic performance by correcting source/sink imbalances. In the context of this subject, we explored the interconnectivity between endogenous electron valves, and the activation of one or more heterologous metabolic sinks. We coexpressed two heterologous metabolic pathways that have been previously shown to positively impact photosynthetic activity in cyanobacteria, a sucrose production pathway (consuming ATP and reductant) and a reductant-only consuming cytochrome P450. Sucrose export was associated with improved quantum yield of phtotosystem II (PSII) and enhanced electron transport chain flux, especially at lower illumination levels, while cytochrome P450 activity led to photosynthetic enhancements primarily observed under high light. Moreover, coexpression of these two heterologous sinks showed additive impacts on photosynthesis, indicating that neither sink alone was capable of utilizing the full “overcapacity” of the electron transport chain. We find that heterologous sinks may partially compensate for the loss of photosystem I (PSI) oxidizing mechanisms even under rapid illumination changes, although this compensation is incomplete. Our results provide support for the theory that heterologous metabolism can act as a photosynthetic sink and exhibit some overlapping functionality with photoprotective mechanisms, while potentially conserving energy within useful metabolic products that might otherwise be “lost.”
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Havurinne V, Handrich M, Antinluoma M, Khorobrykh S, Gould SB, Tyystjärvi E. Genetic autonomy and low singlet oxygen yield support kleptoplast functionality in photosynthetic sea slugs. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:5553-5568. [PMID: 33989402 PMCID: PMC8318255 DOI: 10.1093/jxb/erab216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 05/12/2021] [Indexed: 05/04/2023]
Abstract
The kleptoplastic sea slug Elysia chlorotica consumes Vaucheria litorea, stealing its plastids, which then photosynthesize inside the animal cells for months. We investigated the properties of V. litorea plastids to understand how they withstand the rigors of photosynthesis in isolation. Transcription of specific genes in laboratory-isolated V. litorea plastids was monitored for 7 days. The involvement of plastid-encoded FtsH, a key plastid maintenance protease, in recovery from photoinhibition in V. litorea was estimated in cycloheximide-treated cells. In vitro comparison of V. litorea and spinach thylakoids was applied to investigate reactive oxygen species formation in V. litorea. In comparison to other tested genes, the transcripts of ftsH and translation elongation factor EF-Tu (tufA) decreased slowly in isolated V. litorea plastids. Higher levels of FtsH were also evident in cycloheximide-treated cells during recovery from photoinhibition. Charge recombination in PSII of V. litorea was found to be fine-tuned to produce only small quantities of singlet oxygen, and the plastids also contained reactive oxygen species-protective compounds. Our results support the view that the genetic characteristics of the plastids are crucial in creating a photosynthetic sea slug. The plastid's autonomous repair machinery is likely enhanced by low singlet oxygen production and elevated expression of FtsH.
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Affiliation(s)
- Vesa Havurinne
- Department of Biotechnology/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Maria Handrich
- Department of Biology, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Mikko Antinluoma
- Department of Biotechnology/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Sergey Khorobrykh
- Department of Biotechnology/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Sven B Gould
- Department of Biology, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Esa Tyystjärvi
- Department of Biotechnology/Molecular Plant Biology, University of Turku, Turku, Finland
- Correspondence:
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24
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Havurinne V, Handrich M, Antinluoma M, Khorobrykh S, Gould SB, Tyystjärvi E. Genetic autonomy and low singlet oxygen yield support kleptoplast functionality in photosynthetic sea slugs. JOURNAL OF EXPERIMENTAL BOTANY 2021. [PMID: 33989402 DOI: 10.17632/535dcxjt2d.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The kleptoplastic sea slug Elysia chlorotica consumes Vaucheria litorea, stealing its plastids, which then photosynthesize inside the animal cells for months. We investigated the properties of V. litorea plastids to understand how they withstand the rigors of photosynthesis in isolation. Transcription of specific genes in laboratory-isolated V. litorea plastids was monitored for 7 days. The involvement of plastid-encoded FtsH, a key plastid maintenance protease, in recovery from photoinhibition in V. litorea was estimated in cycloheximide-treated cells. In vitro comparison of V. litorea and spinach thylakoids was applied to investigate reactive oxygen species formation in V. litorea. In comparison to other tested genes, the transcripts of ftsH and translation elongation factor EF-Tu (tufA) decreased slowly in isolated V. litorea plastids. Higher levels of FtsH were also evident in cycloheximide-treated cells during recovery from photoinhibition. Charge recombination in PSII of V. litorea was found to be fine-tuned to produce only small quantities of singlet oxygen, and the plastids also contained reactive oxygen species-protective compounds. Our results support the view that the genetic characteristics of the plastids are crucial in creating a photosynthetic sea slug. The plastid's autonomous repair machinery is likely enhanced by low singlet oxygen production and elevated expression of FtsH.
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Affiliation(s)
- Vesa Havurinne
- Department of Biotechnology/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Maria Handrich
- Department of Biology, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Mikko Antinluoma
- Department of Biotechnology/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Sergey Khorobrykh
- Department of Biotechnology/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Sven B Gould
- Department of Biology, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Esa Tyystjärvi
- Department of Biotechnology/Molecular Plant Biology, University of Turku, Turku, Finland
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Piel T, Sandrini G, Muyzer G, Brussaard CPD, Slot PC, van Herk MJ, Huisman J, Visser PM. Resilience of Microbial Communities after Hydrogen Peroxide Treatment of a Eutrophic Lake to Suppress Harmful Cyanobacterial Blooms. Microorganisms 2021; 9:microorganisms9071495. [PMID: 34361929 PMCID: PMC8304526 DOI: 10.3390/microorganisms9071495] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 07/09/2021] [Accepted: 07/09/2021] [Indexed: 12/23/2022] Open
Abstract
Applying low concentrations of hydrogen peroxide (H2O2) to lakes is an emerging method to mitigate harmful cyanobacterial blooms. While cyanobacteria are very sensitive to H2O2, little is known about the impacts of these H2O2 treatments on other members of the microbial community. In this study, we investigated changes in microbial community composition during two lake treatments with low H2O2 concentrations (target: 2.5 mg L−1) and in two series of controlled lake incubations. The results show that the H2O2 treatments effectively suppressed the dominant cyanobacteria Aphanizomenon klebahnii, Dolichospermum sp. and, to a lesser extent, Planktothrix agardhii. Microbial community analysis revealed that several Proteobacteria (e.g., Alteromonadales, Pseudomonadales, Rhodobacterales) profited from the treatments, whereas some bacterial taxa declined (e.g., Verrucomicrobia). In particular, the taxa known to be resistant to oxidative stress (e.g., Rheinheimera) strongly increased in relative abundance during the first 24 h after H2O2 addition, but subsequently declined again. Alpha and beta diversity showed a temporary decline but recovered within a few days, demonstrating resilience of the microbial community. The predicted functionality of the microbial community revealed a temporary increase of anti-ROS defenses and glycoside hydrolases but otherwise remained stable throughout the treatments. We conclude that the use of low concentrations of H2O2 to suppress cyanobacterial blooms provides a short-term pulse disturbance but is not detrimental to lake microbial communities and their ecosystem functioning.
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Affiliation(s)
- Tim Piel
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090 GE Amsterdam, The Netherlands; (T.P.); (G.S.); (G.M.); (C.P.D.B.); (P.C.S.); (M.J.v.H.); (J.H.)
| | - Giovanni Sandrini
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090 GE Amsterdam, The Netherlands; (T.P.); (G.S.); (G.M.); (C.P.D.B.); (P.C.S.); (M.J.v.H.); (J.H.)
| | - Gerard Muyzer
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090 GE Amsterdam, The Netherlands; (T.P.); (G.S.); (G.M.); (C.P.D.B.); (P.C.S.); (M.J.v.H.); (J.H.)
| | - Corina P. D. Brussaard
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090 GE Amsterdam, The Netherlands; (T.P.); (G.S.); (G.M.); (C.P.D.B.); (P.C.S.); (M.J.v.H.); (J.H.)
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherland Institute for Sea Research, 1790 AB Den Burg, The Netherlands
| | - Pieter C. Slot
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090 GE Amsterdam, The Netherlands; (T.P.); (G.S.); (G.M.); (C.P.D.B.); (P.C.S.); (M.J.v.H.); (J.H.)
| | - Maria J. van Herk
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090 GE Amsterdam, The Netherlands; (T.P.); (G.S.); (G.M.); (C.P.D.B.); (P.C.S.); (M.J.v.H.); (J.H.)
| | - Jef Huisman
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090 GE Amsterdam, The Netherlands; (T.P.); (G.S.); (G.M.); (C.P.D.B.); (P.C.S.); (M.J.v.H.); (J.H.)
| | - Petra M. Visser
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090 GE Amsterdam, The Netherlands; (T.P.); (G.S.); (G.M.); (C.P.D.B.); (P.C.S.); (M.J.v.H.); (J.H.)
- Correspondence: ; Tel.: +31-20-5257073
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26
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CP12 Is Involved in Protection against High Light Intensity by Suppressing the ROS Generation in Synechococcus elongatus PCC7942. PLANTS 2021; 10:plants10071275. [PMID: 34201575 PMCID: PMC8309167 DOI: 10.3390/plants10071275] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/18/2021] [Accepted: 06/21/2021] [Indexed: 11/17/2022]
Abstract
We previously reported that CP12 formed a complex with GAPDH and PRK and regulated the activities of these enzymes and the Calvin-Benson cycle under dark conditions as the principal regulatory system in cyanobacteria. More interestingly, we found that the cyanobacterial CP12 gene-disrupted strain was more sensitive to photo-oxidative stresses such as under high light conditions and paraquat treatment. When a mutant strain that grew normally under low light was subjected to high light conditions, decreases in chlorophyll and photosynthetic activity were observed. Furthermore, a large amount of ROS was accumulated in the cells of the CP12 gene-disrupted strain. These data suggest that CP12 also functions under light conditions and may be involved in protection against oxidative stress by controlling the flow of electrons from Photosystem I to NADPH.
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27
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Kedem I, Milrad Y, Kaplan A, Yacoby I. Juggling Lightning: How Chlorella ohadii handles extreme energy inputs without damage. PHOTOSYNTHESIS RESEARCH 2021; 147:329-344. [PMID: 33389446 DOI: 10.1007/s11120-020-00809-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 12/03/2020] [Indexed: 06/12/2023]
Abstract
The green alga Chlorella ohadii was isolated from a desert biological soil crust, one of the harshest environments on Earth. When grown under optimal laboratory settings it shows the fastest growth rate ever reported for a photosynthetic eukaryote and a complete resistance to photodamage even under unnaturally high light intensities. Here we examined the energy distribution along the photosynthetic pathway under four light and carbon regimes. This was performed using various methodologies such as membrane inlet mass spectrometer with stable O2 isotopes, variable fluorescence, electrochromic shift and fluorescence assessment of NADPH level, as well as the use of specific inhibitors. We show that the preceding illumination and CO2 level during growth strongly affect the energy dissipation strategies employed by the cell. For example, plastid terminal oxidase (PTOX) plays an important role in energy dissipation, particularly in high light- and low-CO2-grown cells. Of particular note is the reliance on PSII cyclic electron flow as an effective and flexible dissipation mechanism in all conditions tested. The energy management observed here may be unique to C. ohadii, as it is the only known organism to cope with such conditions. However, the strategies demonstrated may provide an insight into the processes necessary for photosynthesis under high-light conditions.
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Affiliation(s)
- Isaac Kedem
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, 9190401, Jerusalem, Israel
| | - Yuval Milrad
- School of Plant Sciences and Food Security, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Aaron Kaplan
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, 9190401, Jerusalem, Israel.
| | - Iftach Yacoby
- School of Plant Sciences and Food Security, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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28
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Weenink EFJ, Matthijs HCP, Schuurmans JM, Piel T, van Herk MJ, Sigon CAM, Visser PM, Huisman J. Interspecific protection against oxidative stress: green algae protect harmful cyanobacteria against hydrogen peroxide. Environ Microbiol 2021; 23:2404-2419. [PMID: 33587811 PMCID: PMC8248038 DOI: 10.1111/1462-2920.15429] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 02/08/2021] [Indexed: 11/27/2022]
Abstract
Oceanographic studies have shown that heterotrophic bacteria can protect marine cyanobacteria against oxidative stress caused by hydrogen peroxide (H2O2). Could a similar interspecific protection play a role in freshwater ecosystems? In a series of laboratory experiments and two lake treatments, we demonstrate that freshwater cyanobacteria are sensitive to H2O2 but can be protected by less‐sensitive species such as green algae. Our laboratory results show that green algae degrade H2O2 much faster than cyanobacteria. Consequently, the cyanobacterium Microcystis was able to survive at higher H2O2 concentrations in mixtures with the green alga Chlorella than in monoculture. Interestingly, even the lysate of destructed Chlorella was capable to protect Microcystis, indicating a two‐component H2O2 degradation system in which Chlorella provided antioxidant enzymes and Microcystis the reductants. The level of interspecific protection provided to Microcystis depended on the density of Chlorella. These findings have implications for the mitigation of toxic cyanobacterial blooms, which threaten the water quality of many eutrophic lakes and reservoirs worldwide. In several lakes, H2O2 has been successfully applied to suppress cyanobacterial blooms. Our results demonstrate that high densities of green algae can interfere with these lake treatments, as they may rapidly degrade the added H2O2 and thereby protect the bloom‐forming cyanobacteria.
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Affiliation(s)
- Erik F J Weenink
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, Amsterdam, GE, 1090, The Netherlands
| | - Hans C P Matthijs
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, Amsterdam, GE, 1090, The Netherlands
| | - J Merijn Schuurmans
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, Amsterdam, GE, 1090, The Netherlands
| | - Tim Piel
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, Amsterdam, GE, 1090, The Netherlands
| | - Maria J van Herk
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, Amsterdam, GE, 1090, The Netherlands
| | - Corrien A M Sigon
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, Amsterdam, GE, 1090, The Netherlands
| | - Petra M Visser
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, Amsterdam, GE, 1090, The Netherlands
| | - Jef Huisman
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, Amsterdam, GE, 1090, The Netherlands
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29
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Vicino P, Carrillo J, Gómez R, Shahinnia F, Tula S, Melzer M, Rutten T, Carrillo N, Hajirezaei MR, Lodeyro AF. Expression of Flavodiiron Proteins Flv2-Flv4 in Chloroplasts of Arabidopsis and Tobacco Plants Provides Multiple Stress Tolerance. Int J Mol Sci 2021; 22:1178. [PMID: 33503994 PMCID: PMC7865949 DOI: 10.3390/ijms22031178] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/03/2021] [Accepted: 01/04/2021] [Indexed: 12/14/2022] Open
Abstract
With the notable exception of angiosperms, all phototrophs contain different sets of flavodiiron proteins that help to relieve the excess of excitation energy on the photosynthetic electron transport chain during adverse environmental conditions, presumably by reducing oxygen directly to water. Among them, the Flv2-Flv4 dimer is only found in β-cyanobacteria and induced by high light, supporting a role in stress protection. The possibility of a similar protective function in plants was assayed by expressing Synechocystis Flv2-Flv4 in chloroplasts of tobacco and Arabidopsis. Flv-expressing plants exhibited increased tolerance toward high irradiation, salinity, oxidants, and drought. Stress tolerance was reflected by better growth, preservation of photosynthetic activity, and membrane integrity. Metabolic profiling under drought showed enhanced accumulation of soluble sugars and amino acids in transgenic Arabidopsis and a remarkable shift of sucrose into starch, in line with metabolic responses of drought-tolerant genotypes. Our results indicate that the Flv2-Flv4 complex retains its stress protection activities when expressed in chloroplasts of angiosperm species by acting as an additional electron sink. The flv2-flv4 genes constitute a novel biotechnological tool to generate plants with increased tolerance to agronomically relevant stress conditions that represent a significant productivity constraint.
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Affiliation(s)
- Paula Vicino
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario 2000, Argentina; (P.V.); (J.C.); (R.G.); (N.C.)
| | - Julieta Carrillo
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario 2000, Argentina; (P.V.); (J.C.); (R.G.); (N.C.)
| | - Rodrigo Gómez
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario 2000, Argentina; (P.V.); (J.C.); (R.G.); (N.C.)
| | - Fahimeh Shahinnia
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse, D-06466 Stadt Seeland, Germany; (F.S.); (S.T.); (M.M.); (T.R.)
| | - Suresh Tula
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse, D-06466 Stadt Seeland, Germany; (F.S.); (S.T.); (M.M.); (T.R.)
| | - Michael Melzer
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse, D-06466 Stadt Seeland, Germany; (F.S.); (S.T.); (M.M.); (T.R.)
| | - Twan Rutten
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse, D-06466 Stadt Seeland, Germany; (F.S.); (S.T.); (M.M.); (T.R.)
| | - Néstor Carrillo
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario 2000, Argentina; (P.V.); (J.C.); (R.G.); (N.C.)
| | - Mohammad-Reza Hajirezaei
- Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, Corrensstrasse, D-06466 Stadt Seeland, Germany; (F.S.); (S.T.); (M.M.); (T.R.)
| | - Anabella F. Lodeyro
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario 2000, Argentina; (P.V.); (J.C.); (R.G.); (N.C.)
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Camargo S, Leshkowitz D, Dassa B, Mariscal V, Flores E, Stavans J, Arbel-Goren R. Impaired cell-cell communication in the multicellular cyanobacterium Anabaena affects carbon uptake, photosynthesis, and the cell wall. iScience 2021; 24:101977. [PMID: 33458622 PMCID: PMC7797909 DOI: 10.1016/j.isci.2020.101977] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 11/08/2020] [Accepted: 12/17/2020] [Indexed: 12/23/2022] Open
Abstract
Cell-cell communication is an essential attribute of multicellular organisms. The effects of perturbed communication were studied in septal protein mutants of the heterocyst-forming filamentous cyanobacterium Anabaena sp. PCC 7120 model organism. Strains bearing sepJ and sepJ/fraC/fraD deletions showed differences in growth, pigment absorption spectra, and spatial patterns of expression of the hetR gene encoding a heterocyst differentiation master regulator. Global changes in gene expression resulting from deletion of those genes were mapped by RNA sequencing analysis of wild-type and mutant strains, both under nitrogen-replete and nitrogen-poor conditions. The effects of sepJ and fraC/fraD deletions were non-additive, and perturbed cell-cell communication led to significant changes in global gene expression. Most significant effects, related to carbon metabolism, included increased expression of genes encoding carbon uptake systems and components of the photosynthetic apparatus, as well as decreased expression of genes encoding cell wall components related to heterocyst differentiation and to polysaccharide export.
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Affiliation(s)
- Sergio Camargo
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Dena Leshkowitz
- Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Bareket Dassa
- Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Vicente Mariscal
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Américo Vespucio 49, 41092 Sevilla, Spain
| | - Enrique Flores
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Américo Vespucio 49, 41092 Sevilla, Spain
| | - Joel Stavans
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Rinat Arbel-Goren
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
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Shahinnia F, Tula S, Hensel G, Reiahisamani N, Nasr N, Kumlehn J, Gómez R, Lodeyro AF, Carrillo N, Hajirezaei MR. Plastid-Targeted Cyanobacterial Flavodiiron Proteins Maintain Carbohydrate Turnover and Enhance Drought Stress Tolerance in Barley. FRONTIERS IN PLANT SCIENCE 2021; 11:613731. [PMID: 33519872 PMCID: PMC7838373 DOI: 10.3389/fpls.2020.613731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 12/18/2020] [Indexed: 05/10/2023]
Abstract
Chloroplasts, the sites of photosynthesis in higher plants, have evolved several means to tolerate short episodes of drought stress through biosynthesis of diverse metabolites essential for plant function, but these become ineffective when the duration of the stress is prolonged. Cyanobacteria are the closest bacterial homologs of plastids with two photosystems to perform photosynthesis and to evolve oxygen as a byproduct. The presence of Flv genes encoding flavodiiron proteins has been shown to enhance stress tolerance in cyanobacteria. In an attempt to support the growth of plants exposed to drought, the Synechocystis genes Flv1 and Flv3 were expressed in barley with their products being targeted to the chloroplasts. The heterologous expression of both Flv1 and Flv3 accelerated days to heading, increased biomass, promoted the number of spikes and grains per plant, and improved the total grain weight per plant of transgenic lines exposed to drought. Improved growth correlated with enhanced availability of soluble sugars, a higher turnover of amino acids and the accumulation of lower levels of proline in the leaf. Flv1 and Flv3 maintained the energy status of the leaves in the stressed plants by converting sucrose to glucose and fructose, immediate precursors for energy production to support plant growth under drought. The results suggest that sugars and amino acids play a fundamental role in the maintenance of the energy status and metabolic activity to ensure growth and survival under stress conditions, that is, water limitation in this particular case. Engineering chloroplasts by Flv genes into the plant genome, therefore, has the potential to improve plant productivity wherever drought stress represents a significant production constraint.
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Affiliation(s)
- Fahimeh Shahinnia
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany
| | - Suresh Tula
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany
| | - Goetz Hensel
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany
- Division of Molecular Biology, Centre of the Region Hana for Biotechnological and Agriculture Research, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Narges Reiahisamani
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany
| | - Nasrin Nasr
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany
- Department of Biology, Payame Noor University, Teheran, Iran
| | - Jochen Kumlehn
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany
| | - Rodrigo Gómez
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Anabella F. Lodeyro
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Néstor Carrillo
- Instituto de Biología Molecular y Celular de Rosario (IBR-UNR/CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Mohammad R. Hajirezaei
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany
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Shimakawa G, Hanawa H, Wada S, Hanke GT, Matsuda Y, Miyake C. Physiological Roles of Flavodiiron Proteins and Photorespiration in the Liverwort Marchantia polymorpha. FRONTIERS IN PLANT SCIENCE 2021; 12:668805. [PMID: 34489990 PMCID: PMC8418088 DOI: 10.3389/fpls.2021.668805] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 07/30/2021] [Indexed: 05/19/2023]
Abstract
Against the potential risk in oxygenic photosynthesis, that is, the generation of reactive oxygen species, photosynthetic electron transport needs to be regulated in response to environmental fluctuations. One of the most important regulations is keeping the reaction center chlorophyll (P700) of photosystem I in its oxidized form in excess light conditions. The oxidation of P700 is supported by dissipating excess electrons safely to O2, and we previously found that the molecular mechanism of the alternative electron sink is changed from flavodiiron proteins (FLV) to photorespiration in the evolutionary history from cyanobacteria to plants. However, the overall picture of the regulation of photosynthetic electron transport is still not clear in bryophytes, the evolutionary intermediates. Here, we investigated the physiological roles of FLV and photorespiration for P700 oxidation in the liverwort Marchantia polymorpha by using the mutants deficient in FLV (flv1) at different O2 partial pressures. The effective quantum yield of photosystem II significantly decreased at 2kPa O2 in flv1, indicating that photorespiration functions as the electron sink. Nevertheless, it was clear from the phenotype of flv1 that FLV was dominant for P700 oxidation in M. polymorpha. These data suggested that photorespiration has yet not replaced FLV in functioning for P700 oxidation in the basal land plant probably because of the lower contribution to lumen acidification, compared with FLV, as reflected in the results of electrochromic shift analysis.
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Affiliation(s)
- Ginga Shimakawa
- Graduate School of Agricultural Science, Kobe University, Kobe, Japan
- Research Center for Solar Energy Chemistry, Osaka University, Suita, Japan
- Department of Biosciences, School of Biological and Environmental Sciences, Kwansei-Gakuin University, Nishinomiya, Japan
- Core Research for Environmental Science and Technology, Japan Science and Technology Agency, Chiyoda, Japan
| | - Hitomi Hanawa
- Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Shinya Wada
- Graduate School of Agricultural Science, Kobe University, Kobe, Japan
- Core Research for Environmental Science and Technology, Japan Science and Technology Agency, Chiyoda, Japan
| | - Guy T. Hanke
- School of Biochemistry and Chemistry, Queen Mary University of London, London, United Kingdom
| | - Yusuke Matsuda
- Department of Biosciences, School of Biological and Environmental Sciences, Kwansei-Gakuin University, Nishinomiya, Japan
| | - Chikahiro Miyake
- Graduate School of Agricultural Science, Kobe University, Kobe, Japan
- Core Research for Environmental Science and Technology, Japan Science and Technology Agency, Chiyoda, Japan
- *Correspondence: Chikahiro Miyake,
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33
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Basso L, Yamori W, Szabo I, Shikanai T. Collaboration between NDH and KEA3 Allows Maximally Efficient Photosynthesis after a Long Dark Adaptation. PLANT PHYSIOLOGY 2020; 184:2078-2090. [PMID: 32978277 PMCID: PMC7723091 DOI: 10.1104/pp.20.01069] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 09/16/2020] [Indexed: 05/10/2023]
Abstract
In angiosperms, the NADH dehydrogenase-like (NDH) complex mediates cyclic electron transport around PSI (CET). K+ Efflux Antiporter3 (KEA3) is a putative thylakoid H+/K+ antiporter and allows an increase in membrane potential at the expense of the ∆pH component of the proton motive force. In this study, we discovered that the chlororespiratory reduction2-1 (crr2-1) mutation, which abolished NDH-dependent CET, enhanced the kea3-1 mutant phenotypes in Arabidopsis (Arabidopsis thaliana). The NDH complex pumps protons during CET, further enhancing ∆pH, but its physiological function has not been fully clarified. The observed effect only took place upon exposure to light of 110 µmol photons m-2 s-1 after overnight dark adaptation. We propose two distinct modes of NDH action. In the initial phase, within 1 min after the onset of actinic light, the NDH-dependent CET engages with KEA3 to enhance electron transport efficiency. In the subsequent phase, in which the ∆pH-dependent down-regulation of the electron transport is relaxed, the NDH complex engages with KEA3 to relax the large ∆pH formed during the initial phase. We observed a similar impact of the crr2-1 mutation in the genetic background of the PROTON GRADIENT REGULATION5 overexpression line, in which the size of ∆pH was enhanced. When photosynthesis was induced at 300 µmol photons m-2 s-1, the contribution of KEA3 was negligible in the initial phase and the ∆pH-dependent down-regulation was not relaxed in the second phase. In the crr2-1 kea3-1 double mutant, the induction of CO2 fixation was delayed after overnight dark adaptation.
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Affiliation(s)
- Leonardo Basso
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502 Japan
| | - Wataru Yamori
- Institute for Sustainable Agro-Ecosystem Services, Graduate School of Agriculture and Life Science, University of Tokyo, Tokyo 188-0002 Japan
| | - Ildiko Szabo
- Department of Biology, University of Padova, 606-8502 Padova, Italy
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502 Japan
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Sandrini G, Piel T, Xu T, White E, Qin H, Slot PC, Huisman J, Visser PM. Sensitivity to hydrogen peroxide of the bloom-forming cyanobacterium Microcystis PCC 7806 depends on nutrient availability. HARMFUL ALGAE 2020; 99:101916. [PMID: 33218441 DOI: 10.1016/j.hal.2020.101916] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 10/02/2020] [Accepted: 10/07/2020] [Indexed: 06/11/2023]
Abstract
Application of low concentrations of hydrogen peroxide (H2O2) is a relatively new and promising method to selectively suppress harmful cyanobacterial blooms, while minimizing effects on eukaryotic organisms. However, it is still unknown how nutrient limitation affects the sensitivity of cyanobacteria to H2O2. In this study, we compare effects of H2O2 on the microcystin-producing cyanobacterium Microcystis PCC 7806 under light-limited but nutrient-replete conditions, nitrogen (N) limitation and phosphorus (P) limitation. Microcystis was first grown in chemostats to acclimate to these different experimental conditions, and subsequently transferred to batch cultures where they were treated with a range of H2O2 concentrations (0-10 mg L-1) while exposed to high light (100 µmol photons m-2 s-1) or low light (15 µmol photons m-2 s-1). Our results show that, at low light, N- and P-limited Microcystis were less sensitive to H2O2 than light-limited but nutrient-replete Microcystis. A significantly higher expression of the genes encoding for anti-oxidative stress enzymes (2-cys-peroxiredoxin, thioredoxin A and type II peroxiredoxin) was observed prior to and after the H2O2 treatment for both N- and P-limited Microcystis, which may explain their increased resistance against H2O2. At high light, Microcystis was more sensitive to H2O2 than at low light, and differences in the decline of the photosynthetic yield between nutrient-replete and nutrient-limited Microcystis exposed to H2O2 were less pronounced. Leakage of microcystin was stronger and faster from nutrient-replete than from N- and P-limited Microcystis. Overall, this study provides insight in the sensitivity of harmful cyanobacteria to H2O2 under various environmental conditions.
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Affiliation(s)
- Giovanni Sandrini
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - Tim Piel
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - Tianshuo Xu
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - Emily White
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - Hongjie Qin
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands; Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Pieter C Slot
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - Jef Huisman
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - Petra M Visser
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands.
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35
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Foo SC, Chapman IJ, Hartnell DM, Turner AD, Franklin DJ. Effects of H 2O 2 on growth, metabolic activity and membrane integrity in three strains of Microcystis aeruginosa. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:38916-38927. [PMID: 32638304 DOI: 10.1007/s11356-020-09729-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 06/12/2020] [Indexed: 06/11/2023]
Abstract
The application of hydrogen peroxide (H2O2) as a management tool to control Microcystis blooms has become increasingly popular due to its short lifetime and targeted action. H2O2 increases intracellular reactive oxygen species resulting in oxidative stress and subsequently cell death. H2O2 is naturally produced in freshwater bodies as a result of photocatalytic reactions between dissolved organic carbon and sunlight. Previously, some studies have suggested that this environmental source of H2O2 selectively targets for toxigenic cyanobacteria strains in the genus Microcystis. Also, past studies only focused on the morphological and biochemical changes of H2O2-induced cell death in Microcystis with little information available on the effects of different H2O2 concentrations on growth, esterase activity and membrane integrity. Therefore, this study investigated the effects of non-lethal (40-4000 nM) concentrations on percentage cell death; with a focus on sub-lethal (50 μM) and lethal (275 μM; 500 μM) doses of H2O2 on growth, cells showing esterase activity and membrane integrity. The non-lethal dose experiment was part of a preliminary study. Results showed a dose- and time-dependent relationship in all three Microcystis strains post H2O2 treatment. H2O2 resulted in a significant increase in intracellular reactive oxygen species, decreased chlorophyll a content, decreased growth rate and esterase activity. Interestingly, at sub-lethal (50 μM H2O2 treatment), percentage of dead cells in microcystin-producing strains was significantly higher (p < 0.05) than that in non-microcystin-producing strains at 72 h. These findings further cement our understanding of the influence of H2O2 on different strains of Microcystis and its impact on membrane integrity and metabolic physiology: important to future toxic bloom control programmes.
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Affiliation(s)
- Su Chern Foo
- Department of Life & Environmental Sciences, Faculty of Science & Technology, Bournemouth University, Talbot Campus, Fern Barrow, Poole, Dorset, BH12 5BB, UK.
- School of Science, Monash University Malaysia, Jalan Lagoon Selatan, 47500, Bandar Sunway, Selangor Darul Ehsan, Malaysia.
| | - Ian J Chapman
- Department of Life & Environmental Sciences, Faculty of Science & Technology, Bournemouth University, Talbot Campus, Fern Barrow, Poole, Dorset, BH12 5BB, UK
- New South Wales Shellfish Program, NSW Food Authority, Taree, NSW, 2430, Australia
| | - David M Hartnell
- Department of Life & Environmental Sciences, Faculty of Science & Technology, Bournemouth University, Talbot Campus, Fern Barrow, Poole, Dorset, BH12 5BB, UK
- Centre for Environment, Fisheries and Aquaculture Science (CEFAS), The Nothe, Barrack Road, Weymouth, Dorset, DT4 8UB, UK
| | - Andrew D Turner
- Centre for Environment, Fisheries and Aquaculture Science (CEFAS), The Nothe, Barrack Road, Weymouth, Dorset, DT4 8UB, UK
| | - Daniel J Franklin
- Department of Life & Environmental Sciences, Faculty of Science & Technology, Bournemouth University, Talbot Campus, Fern Barrow, Poole, Dorset, BH12 5BB, UK
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Storti M, Segalla A, Mellon M, Alboresi A, Morosinotto T. Regulation of electron transport is essential for photosystem I stability and plant growth. THE NEW PHYTOLOGIST 2020; 228:1316-1326. [PMID: 32367526 DOI: 10.1111/nph.16643] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 04/27/2020] [Indexed: 06/11/2023]
Abstract
Photosynthetic electron transport is regulated by cyclic and pseudocyclic electron flow (CEF and PCEF) to maintain the balance between light availability and metabolic demands. CEF transfers electrons from photosystem I to the plastoquinone pool with two mechanisms, dependent either on PGR5/PGRL1 or on the type I NADH dehydrogenase-like (NDH) complex. PCEF uses electrons from photosystem I to reduce oxygen and in many groups of photosynthetic organisms, but remarkably not in angiosperms, it is catalyzed by flavodiiron proteins (FLVs). In this study, Physcomitrella patens plants depleted in PGRL1, NDH and FLVs in different combinations were generated and characterized, showing that all these mechanisms are active in this moss. Surprisingly, in contrast to flowering plants, Physcomitrella patens can cope with the simultaneous inactivation of PGR5- and NDH-dependent CEF but, when FLVs are also depleted, plants show strong growth reduction and photosynthetic activity is drastically reduced. The results demonstrate that mechanisms for modulation of photosynthetic electron transport have large functional overlap but are together indispensable to protect photosystem I from damage and they are an essential component for photosynthesis in any light regime.
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Affiliation(s)
- Mattia Storti
- Department of Biology, University of Padova, Padova, 35121, Italy
| | - Anna Segalla
- Department of Biology, University of Padova, Padova, 35121, Italy
| | - Marco Mellon
- Department of Biology, University of Padova, Padova, 35121, Italy
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Havurinne V, Tyystjärvi E. Photosynthetic sea slugs induce protective changes to the light reactions of the chloroplasts they steal from algae. eLife 2020; 9:57389. [PMID: 33077025 PMCID: PMC7679141 DOI: 10.7554/elife.57389] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 10/07/2020] [Indexed: 12/13/2022] Open
Abstract
Sacoglossan sea slugs are able to maintain functional chloroplasts inside their own cells, and mechanisms that allow preservation of the chloroplasts are unknown. We found that the slug Elysia timida induces changes to the photosynthetic light reactions of the chloroplasts it steals from the alga Acetabularia acetabulum. Working with a large continuous laboratory culture of both the slugs (>500 individuals) and their prey algae, we show that the plastoquinone pool of slug chloroplasts remains oxidized, which can suppress reactive oxygen species formation. Slug chloroplasts also rapidly build up a strong proton-motive force upon a dark-to-light transition, which helps them to rapidly switch on photoprotective non-photochemical quenching of excitation energy. Finally, our results suggest that chloroplasts inside E. timida rely on oxygen-dependent electron sinks during rapid changes in light intensity. These photoprotective mechanisms are expected to contribute to the long-term functionality of the chloroplasts inside the slugs. Plants, algae and a few other organisms rely on a process known as photosynthesis to fuel themselves, as they can harness cellular structures called chloroplasts to convert light into usable energy. Animals typically lack chloroplasts, making them unable to use photosynthesis to power themselves. The sea slug Elysia timida, however, can steal whole chloroplasts from the cells of the algae it consumes: the stolen structures then become part of the cells in the gut of the slug, allowing the animal to gain energy from sunlight. Once they are in the digestive system of the slug, the chloroplasts survive and keep working for longer than expected. Indeed, these structures are often harmed as a side effect of photosynthesis, but the sea slug does not have the right genes to help repair this damage. In addition, conditions inside animal cells are widely different to the ones found inside algae and plants. It is not clear then how the sea slug extends the lifespan of its chloroplasts by preventing damage caused by sunlight. To investigate this question, Havurinne and Tyystjärvi compared photosynthesis in sea slugs and the algae they eat. A range of methods, including measuring fluorescence from the chloroplasts, was used: this revealed that the slug changes the inside of the stolen chloroplasts, making them more resistant to damage. First, when exposed to light the stolen chloroplasts can quickly switch on a mechanism that dissipates light energy to heat, which is less damaging. Second, a molecule that serves as an intermediate during photosynthesis is kept in a ‘safe’ state which prevents it from creating harmful compounds. And finally, additional safeguard molecules ‘deactivate’ compounds that could otherwise mediate damaging reactions. Overall, these measures may reduce the efficiency of the chloroplasts but allow them to keep working for much longer. Early chloroplasts were probably independent bacteria that were captured and ‘domesticated’ by other cells for their ability to extract energy from the sun. Photosynthesizing sea slugs therefore provide an interesting way to understand some of the challenges of early life. The work by Havurinne and Tyystjärvi may also reveal new ways to harness biological processes such as photosynthesis for energy production in other contexts.
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Affiliation(s)
- Vesa Havurinne
- University of Turku, Department of Biochemistry / Molecular Plant Biology, Turku, Finland
| | - Esa Tyystjärvi
- University of Turku, Department of Biochemistry / Molecular Plant Biology, Turku, Finland
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Assil-Companioni L, Büchsenschütz HC, Solymosi D, Dyczmons-Nowaczyk NG, Bauer KKF, Wallner S, Macheroux P, Allahverdiyeva Y, Nowaczyk MM, Kourist R. Engineering of NADPH Supply Boosts Photosynthesis-Driven Biotransformations. ACS Catal 2020; 10:11864-11877. [PMID: 33101760 PMCID: PMC7574619 DOI: 10.1021/acscatal.0c02601] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 09/04/2020] [Indexed: 02/08/2023]
Abstract
![]()
Light-driven biocatalysis
in recombinant cyanobacteria provides
highly atom-efficient cofactor regeneration via photosynthesis,
thereby remediating constraints associated with sacrificial cosubstrates.
However, despite the remarkable specific activities of photobiocatalysts,
self-shading at moderate-high cell densities limits efficient space-time-yields
of heterologous enzymatic reactions. Moreover, efficient integration
of an artificial electron sink into the tightly regulated network
of cyanobacterial electron pathways can be highly challenging. Here,
we used C=C bond reduction of 2-methylmaleimide by the NADPH-dependent
ene-reductase YqjM as a model reaction for light-dependent biotransformations.
Time-resolved NADPH fluorescence spectroscopy allowed direct monitoring
of in-cell YqjM activity and revealed differences in NADPH steady-state
levels and oxidation kinetics between different genetic constructs.
This effect correlates with specific activities of whole-cells, which
demonstrated conversions of >99%. Further channelling of electrons
toward heterologous YqjM by inactivation of the flavodiiron proteins
(Flv1/Flv3) led to a 2-fold improvement in specific activity at moderate
cell densities, thereby elucidating the possibility of accelerating
light-driven biotransformations by the removal of natural competing
electron sinks. In the best case, an initial product formation rate
of 18.3 mmol h–1 L–1 was reached,
allowing the complete conversion of a 60 mM substrate solution within
4 h.
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Affiliation(s)
- Leen Assil-Companioni
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
- ACIB GmbH, Petersgasse 14, 8010 Graz, Austria
| | - Hanna C. Büchsenschütz
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
| | - Dániel Solymosi
- Molecular Plant Biology unit, Department of Biochemistry, Faculty of Science and Engineering, University of Turku, Turku 20014, Finland
| | - Nina G. Dyczmons-Nowaczyk
- Department of Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - Kristin K. F. Bauer
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
| | - Silvia Wallner
- Institute of Biochemistry, Graz University of Technology, Petersgasse 10, 8010 Graz, Austria
| | - Peter Macheroux
- Institute of Biochemistry, Graz University of Technology, Petersgasse 10, 8010 Graz, Austria
| | - Yagut Allahverdiyeva
- Molecular Plant Biology unit, Department of Biochemistry, Faculty of Science and Engineering, University of Turku, Turku 20014, Finland
| | - Marc M. Nowaczyk
- Department of Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - Robert Kourist
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
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Kashimoto T, Miyake K, Sato M, Maeda K, Matsumoto C, Ikeuchi M, Toyooka K, Watanabe S, Kanesaki Y, Narikawa R. Acclimation process of the chlorophyll d-bearing cyanobacterium Acaryochloris marina to an orange light environment revealed by transcriptomic analysis and electron microscopic observation. J GEN APPL MICROBIOL 2020; 66:106-115. [PMID: 32147625 DOI: 10.2323/jgam.2019.11.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The cyanobacterium Acaryochloris marina MBIC 11017 (A. marina 11017) possesses chlorophyll d (Chl. d) peaking at 698 nm as photosystem reaction center pigments, instead of chlorophyll a (Chl. a) peaking at 665 nm. About 95% of the total chlorophylls is Chl. d in A. marina 11017. In addition, A. marina 11017 possesses phycobilisome (PBS) supercomplex to harvest orange light and to transfer the absorbing energy to the photosystems. In this context, A. marina 11017 utilizes both far-red and orange light as the photosynthetic energy source. In the present study, we incubated A. marina 11017 cells under monochromatic orange and far-red light conditions and performed transcriptional and morphological studies by RNA-seq analysis and electron microscopy. Cellular absorption spectra, transcriptomic profiles, and microscopic observations demonstrated that PBS was highly accumulated under an orange light condition relative to a far-red light condition. Notably, transcription of one cpcBA operon encoding the phycobiliprotein of the phycocyanin was up-regulated under the orange light condition, but another operon was constitutively expressed under both conditions, indicating functional diversification of these two operons for light harvesting. Taking the other observations into consideration, we could illustrate the photoacclimation processes of A. marina 11017 in response to orange and far-red light conditions in detail.
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Affiliation(s)
- Tomonori Kashimoto
- Department of Biological Science, Faculty of Science, Shizuoka University
| | - Keita Miyake
- Department of Biological Science, Faculty of Science, Shizuoka University
| | - Mayuko Sato
- RIKEN Center for Sustainable Resource Science
| | - Kaisei Maeda
- Department of Life Sciences (Biology), Graduate School of Arts and Sciences, The University of Tokyo.,Department of Bioscience, Tokyo University of Agriculture
| | | | - Masahiko Ikeuchi
- Department of Life Sciences (Biology), Graduate School of Arts and Sciences, The University of Tokyo.,Core Research for Evolutional Science and Technology, Japan Science and Technology Agency
| | | | | | - Yu Kanesaki
- Research Institute of Green Science and Technology, Shizuoka University.,NODAI Genome Research Center, Tokyo University of Agriculture
| | - Rei Narikawa
- Department of Biological Science, Faculty of Science, Shizuoka University.,Core Research for Evolutional Science and Technology, Japan Science and Technology Agency.,Research Institute of Green Science and Technology, Shizuoka University
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40
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Ueno Y, Shimakawa G, Aikawa S, Miyake C, Akimoto S. Photoprotection mechanisms under different CO 2 regimes during photosynthesis in a green alga Chlorella variabilis. PHOTOSYNTHESIS RESEARCH 2020; 144:397-407. [PMID: 32377933 DOI: 10.1007/s11120-020-00757-4] [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: 12/27/2019] [Accepted: 04/23/2020] [Indexed: 05/28/2023]
Abstract
Oxygenic photosynthesis converts light energy into chemical energy via electron transport and assimilates CO2 in the Calvin-Benson cycle with the chemical energy. Thus, high light and low CO2 conditions induce the accumulation of electrons in the photosynthetic electron transport system, resulting in the formation of reactive oxygen species. To prevent the accumulation of electrons, oxygenic photosynthetic organisms have developed photoprotection mechanisms, including non-photochemical quenching (NPQ) and alternative electron flow (AEF). There are diverse molecular mechanisms underlying NPQ and AEF, and the corresponding molecular actors have been identified and characterized using a model green alga Chlamydomonas reinhardtii. In contrast, detailed information about the photoprotection mechanisms is lacking for other green algal species. In the current study, we examined the photoprotection mechanisms responsive to CO2 in the green alga Chlorella variabilis by combining the analyses of pulse-amplitude-modulated fluorescence, O2 evolution, and the steady-state and time-resolved fluorescence spectra. Under the CO2-limited condition, ΔpH-dependent NPQ occurred in photosystems I and II. Moreover, O2-dependent AEF was also induced. Under the CO2-limited condition with carbon supplementation, NPQ was relaxed and light-harvesting chlorophyll-protein complex II was isolated from both photosystems. In C. variabilis, the O2-dependent AEF and the mechanisms that instantly convert the light-harvesting functions of both photosystems may be important for maintaining efficient photosynthetic activities under various CO2 conditions.
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Affiliation(s)
- Yoshifumi Ueno
- Graduate School of Science, Kobe University, Kobe, 657-8501, Japan.
| | - Ginga Shimakawa
- Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
- Institute for Integrative Biology of the Cell, CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Shimpei Aikawa
- Japan International Research Center for Agricultural Sciences, Tsukuba, 305-8686, Japan
| | - Chikahiro Miyake
- Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
| | - Seiji Akimoto
- Graduate School of Science, Kobe University, Kobe, 657-8501, Japan.
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Solymosi D, Nikkanen L, Muth-Pawlak D, Fitzpatrick D, Vasudevan R, Howe CJ, Lea-Smith DJ, Allahverdiyeva Y. Cytochrome c M Decreases Photosynthesis under Photomixotrophy in Synechocystis sp. PCC 6803. PLANT PHYSIOLOGY 2020; 183:700-716. [PMID: 32317358 PMCID: PMC7271781 DOI: 10.1104/pp.20.00284] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 03/23/2020] [Indexed: 05/26/2023]
Abstract
Photomixotrophy is a metabolic state that enables photosynthetic microorganisms to simultaneously perform photosynthesis and metabolism of imported organic carbon substrates. This process is complicated in cyanobacteria, since many, including Synechocystis sp. PCC 6803, conduct photosynthesis and respiration in an interlinked thylakoid membrane electron transport chain. Under photomixotrophy, the cell must therefore tightly regulate electron fluxes from photosynthetic and respiratory complexes. In this study, we demonstrate, via characterization of photosynthetic apparatus and the proteome, that photomixotrophic growth results in a gradual inhibition of QA - reoxidation in wild-type Synechocystis, which largely decreases photosynthesis over 3 d of growth. This process is circumvented by deleting the gene encoding cytochrome c M (CytM), a cryptic c-type heme protein widespread in cyanobacteria. The ΔCytM strain maintained active photosynthesis over the 3-d period, demonstrated by high photosynthetic O2 and CO2 fluxes and effective yields of PSI and PSII. Overall, this resulted in a higher growth rate compared to that of the wild type, which was maintained by accumulation of proteins involved in phosphate and metal uptake, and cofactor biosynthetic enzymes. While the exact role of CytM has not been determined, a mutant deficient in the thylakoid-localized respiratory terminal oxidases and CytM (ΔCox/Cyd/CytM) displayed a phenotype similar to that of ΔCytM under photomixotrophy. This, in combination with other physiological data, and in contrast to a previous hypothesis, suggests that CytM does not transfer electrons to these complexes. In summary, our data suggest that CytM may have a regulatory role in photomixotrophy by modulating the photosynthetic capacity of cells.
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Affiliation(s)
- Daniel Solymosi
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland
| | - Lauri Nikkanen
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland
| | - Dorota Muth-Pawlak
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland
| | - Duncan Fitzpatrick
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland
| | - Ravendran Vasudevan
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | - Christopher J Howe
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | - David J Lea-Smith
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Yagut Allahverdiyeva
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku FI-20014, Finland
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42
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Kannchen D, Zabret J, Oworah-Nkruma R, Dyczmons-Nowaczyk N, Wiegand K, Löbbert P, Frank A, Nowaczyk MM, Rexroth S, Rögner M. Remodeling of photosynthetic electron transport in Synechocystis sp. PCC 6803 for future hydrogen production from water. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148208. [PMID: 32339488 DOI: 10.1016/j.bbabio.2020.148208] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 03/16/2020] [Accepted: 04/14/2020] [Indexed: 02/06/2023]
Abstract
Photosynthetic microorganisms such as the cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis) can be exploited for the light-driven synthesis of valuable compounds. Thermodynamically, it is most beneficial to branch-off photosynthetic electrons at ferredoxin (Fd), which provides electrons for a variety of fundamental metabolic pathways in the cell, with the ferredoxin-NADP+ Oxido-Reductase (FNR, PetH) being the main target. In order to re-direct electrons from Fd to another consumer, the high electron transport rate between Fd and FNR has to be reduced. Based on our previous in vitro experiments, corresponding FNR-mutants at position FNR_K190 (Wiegand, K., et al.: "Rational redesign of the ferredoxin-NADP-oxido-reductase/ferredoxin-interaction for photosynthesis-dependent H2-production". Biochim Biophys Acta, 2018) have been generated in Synechocystis cells to study their impact on the cellular metabolism and their potential for a future hydrogen-producing design cell. Out of two promising candidates, mutation FNR_K190D proved to be lethal due to oxidative stress, while FNR_K190A was successfully generated and characterized: The light induced NADPH formation is clearly impaired in this mutant and it shows also major metabolic adaptations like a higher glucose metabolism as evidenced by quantitative mass spectrometric analysis. These results indicate a high potential for the future use of photosynthetic electrons in engineered design cells - for instance for hydrogen production. They also show substantial differences of interacting proteins in an in vitro environment vs. physiological conditions in whole cells.
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Affiliation(s)
- Daniela Kannchen
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Jure Zabret
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Regina Oworah-Nkruma
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Nina Dyczmons-Nowaczyk
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Katrin Wiegand
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Pia Löbbert
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Anna Frank
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Marc Michael Nowaczyk
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Sascha Rexroth
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Matthias Rögner
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University Bochum, 44780 Bochum, Germany.
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Kłodawska K, Kovács L, Vladkova R, Rzaska A, Gombos Z, Laczkó-Dobos H, Malec P. Trimeric organization of photosystem I is required to maintain the balanced photosynthetic electron flow in cyanobacterium Synechocystis sp. PCC 6803. PHOTOSYNTHESIS RESEARCH 2020; 143:251-262. [PMID: 31848802 DOI: 10.1007/s11120-019-00696-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 12/02/2019] [Indexed: 06/10/2023]
Abstract
In Synechocystis sp. PCC 6803 and some other cyanobacteria photosystem I reaction centres exist predominantly as trimers, with minor contribution of monomeric form, when cultivated at standard optimized conditions. In contrast, in plant chloroplasts photosystem I complex is exclusively monomeric. The functional significance of trimeric organization of cyanobacterial photosystem I remains not fully understood. In this study, we compared the photosynthetic characteristics of PSI in wild type and psaL knockout mutant. The results show that relative to photosystem I trimer in wild-type cells, photosystem I monomer in psaL- mutant has a smaller P700+ pool size under low and moderate light, slower P700 oxidation upon dark-to-light transition, and slower P700+ reduction upon light-to-dark transition. The mutant also shows strongly diminished photosystem I donor side limitations [quantum yield Y(ND)] at low, moderate and high light, but enhanced photosystem I acceptor side limitations [quantum yield Y(NA)], especially at low light (22 µmol photons m-2 s-1). In line with these functional characteristics are the determined differences in the relative expression genes encoding of selected electron transporters. The psaL- mutant showed significant (ca fivefold) upregulation of the photosystem I donor cytochrome c6, and downregulation of photosystem I acceptors (ferredoxin, flavodoxin) and proteins of alternative electron flows originating in photosystem I acceptor side. Taken together, our results suggest that photosystem I trimerization in wild-type Synechocystis cells plays a role in the protection of photosystem I from photoinhibition via maintaining enhanced donor side electron transport limitations and minimal acceptor side electron transport limitations at various light intensities.
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Affiliation(s)
- Kinga Kłodawska
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387, Kraków, Poland.
| | - László Kovács
- Biological Research Centre, Hungarian Academy of Sciences, Szeged, 6726, Hungary
| | - Radka Vladkova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria
| | - Agnieszka Rzaska
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387, Kraków, Poland
| | - Zoltán Gombos
- Biological Research Centre, Hungarian Academy of Sciences, Szeged, 6726, Hungary
| | | | - Przemysław Malec
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387, Kraków, Poland
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44
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Yang Q, Blanco NE, Hermida-Carrera C, Lehotai N, Hurry V, Strand Å. Two dominant boreal conifers use contrasting mechanisms to reactivate photosynthesis in the spring. Nat Commun 2020; 11:128. [PMID: 31913273 PMCID: PMC6949249 DOI: 10.1038/s41467-019-13954-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 12/05/2019] [Indexed: 01/25/2023] Open
Abstract
Boreal forests are dominated by evergreen conifers that show strongly regulated seasonal photosynthetic activity. Understanding the mechanisms behind seasonal modulation of photosynthesis is crucial for predicting how these forests will respond to changes in seasonal patterns and how this will affect their role in the terrestrial carbon cycle. We demonstrate that the two co-occurring dominant boreal conifers, Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies), use contrasting mechanisms to reactivate photosynthesis in the spring. Scots pine downregulates its capacity for CO2 assimilation during winter and activates alternative electron sinks through accumulation of PGR5 and PGRL1 during early spring until the capacity for CO2 assimilation is recovered. In contrast, Norway spruce lacks this ability to actively switch between different electron sinks over the year and as a consequence suffers severe photooxidative damage during the critical spring period.
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Affiliation(s)
- Qi Yang
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE 901 87, Umeå, Sweden
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, 100091, China
| | - Nicolás E Blanco
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE 901 87, Umeå, Sweden.
- Centre of Photosynthetic and Biochemical Studies (CEFOBI-CONICET), Faculty of Biochemical Science and Pharmacy, Rosario National University, S2002LRK, Rosario, Argentina.
| | - Carmen Hermida-Carrera
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE 901 87, Umeå, Sweden
| | - Nóra Lehotai
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE 901 87, Umeå, Sweden
| | - Vaughan Hurry
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE 901 83, Umeå, Sweden.
| | - Åsa Strand
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE 901 87, Umeå, Sweden.
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Raven JA, Beardall J, Quigg A. Light-Driven Oxygen Consumption in the Water-Water Cycles and Photorespiration, and Light Stimulated Mitochondrial Respiration. PHOTOSYNTHESIS IN ALGAE: BIOCHEMICAL AND PHYSIOLOGICAL MECHANISMS 2020. [DOI: 10.1007/978-3-030-33397-3_8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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46
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Piel T, Sandrini G, White E, Xu T, Schuurmans JM, Huisman J, Visser PM. Suppressing Cyanobacteria with Hydrogen Peroxide Is More Effective at High Light Intensities. Toxins (Basel) 2019; 12:toxins12010018. [PMID: 31906135 PMCID: PMC7020451 DOI: 10.3390/toxins12010018] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/18/2019] [Accepted: 12/20/2019] [Indexed: 12/01/2022] Open
Abstract
Hydrogen peroxide (H2O2) can be used as an emergency method to selectively suppress cyanobacterial blooms in lakes and drinking water reservoirs. However, it is largely unknown how environmental parameters alter the effectiveness of H2O2 treatments. In this study, the toxic cyanobacterial strain Microcystis aeruginosa PCC 7806 was treated with a range of H2O2 concentrations (0 to 10 mg/L), while being exposed to different light intensities and light colors. H2O2 treatments caused a stronger decline of the photosynthetic yield in high light than in low light or in the dark, and also a stronger decline in orange than in blue light. Our results are consistent with the hypothesis that H2O2 causes major damage at photosystem II (PSII) and interferes with PSII repair, which makes cells more sensitive to photoinhibition. Furthermore, H2O2 treatments caused a decrease in cell size and an increase in extracellular microcystin concentrations, indicative of leakage from disrupted cells. Our findings imply that even low H2O2 concentrations of 1–2 mg/L can be highly effective, if cyanobacteria are exposed to high light intensities. We therefore recommend performing lake treatments during sunny days, when a low H2O2 dosage is sufficient to suppress cyanobacteria, and may help to minimize impacts on non-target organisms.
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Sagun JV, Badger MR, Chow WS, Ghannoum O. Cyclic electron flow and light partitioning between the two photosystems in leaves of plants with different functional types. PHOTOSYNTHESIS RESEARCH 2019; 142:321-334. [PMID: 31520186 PMCID: PMC6874625 DOI: 10.1007/s11120-019-00666-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 08/26/2019] [Indexed: 05/05/2023]
Abstract
Cyclic electron flow (CEF) around photosystem I (PSI) is essential for generating additional ATP and enhancing efficient photosynthesis. Accurate estimation of CEF requires knowledge of the fractions of absorbed light by PSI (fI) and PSII (fII), which are only known for a few model species such as spinach. No measures of fI are available for C4 grasses under different irradiances. We developed a new method to estimate (1) fII in vivo by concurrently measuring linear electron flux through both photosystems [Formula: see text] in leaf using membrane inlet mass spectrometry (MIMS) and total electron flux through PSII (ETR2) using chlorophyll fluorescence by a Dual-PAM at low light and (2) CEF as ETR1-[Formula: see text]. For a C3 grass, fI was 0.5 and 0.4 under control (high light) and shade conditions, respectively. C4 species belonging to NADP-ME and NAD-ME subtypes had fI of 0.6 and PCK subtype had 0.5 under control. All shade-grown C4 species had fI of 0.6 except for NADP-ME grass which had 0.7. It was also observed that fI ranged between 0.3 and 0.5 for gymnosperm, liverwort and fern species. CEF increased with irradiance and was induced at lower irradiances in C4 grasses and fern relative to other species. CEF was greater in shade-grown plants relative to control plants except for C4 NADP-ME species. Our study reveals a range of CEF and fI values in different plant functional groups. This variation must be taken into account for improved photosynthetic calculations and modelling.
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Affiliation(s)
- Julius Ver Sagun
- ARC Centre of Excellence for Translational Photosynthesis, Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, Locked Bag 1797, Penrith, NSW 2751 Australia
| | - Murray R. Badger
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, ACT 2601 Australia
| | - Wah Soon Chow
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, ACT 2601 Australia
| | - Oula Ghannoum
- ARC Centre of Excellence for Translational Photosynthesis, Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, Locked Bag 1797, Penrith, NSW 2751 Australia
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Thiel K, Patrikainen P, Nagy C, Fitzpatrick D, Pope N, Aro EM, Kallio P. Redirecting photosynthetic electron flux in the cyanobacterium Synechocystis sp. PCC 6803 by the deletion of flavodiiron protein Flv3. Microb Cell Fact 2019; 18:189. [PMID: 31690310 PMCID: PMC6833302 DOI: 10.1186/s12934-019-1238-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 10/23/2019] [Indexed: 01/20/2023] Open
Abstract
Background Oxygen-evolving photoautotrophic organisms, like cyanobacteria, protect their photosynthetic machinery by a number of regulatory mechanisms, including alternative electron transfer pathways. Despite the importance in modulating the electron flux distribution between the photosystems, alternative electron transfer routes may compete with the solar-driven production of CO2-derived target chemicals in biotechnological systems under development. This work focused on engineered cyanobacterial Synechocystis sp. PCC 6803 strains, to explore possibilities to rescue excited electrons that would normally be lost to molecular oxygen by an alternative acceptor flavodiiron protein Flv1/3—an enzyme that is natively associated with transfer of electrons from PSI to O2, as part of an acclimation strategy towards varying environmental conditions. Results The effects of Flv1/3 inactivation by flv3 deletion were studied in respect to three alternative end-products, sucrose, polyhydroxybutyrate and glycogen, while the photosynthetic gas fluxes were monitored by Membrane Inlet Mass Spectrometry (MIMS) to acquire information on cellular carbon uptake, and the production and consumption of O2. The results demonstrated that a significant proportion of the excited electrons derived from photosynthetic water cleavage was lost to molecular oxygen via Flv1/3 in cells grown under high CO2, especially under high light intensities. In flv3 deletion strains these electrons could be re-routed to increase the relative metabolic flux towards the monitored target products, but the carbon distribution and the overall efficiency were determined by the light conditions and the genetic composition of the respective pathways. At the same time, the total photosynthetic capacity of the Δflv3 strains was systematically reduced, and accompanied by upregulation of oxidative glycolytic metabolism in respect to controls with the native Flv1/3 background. Conclusions The observed metabolic changes and respective production profiles were proposedly linked with the lack of Flv1/3-mediated electron transfer, and the associated decrease in the intracellular ATP/NADPH ratio, which is bound to affect the metabolic carbon partitioning in the flv3-deficient cells. While the deletion of flv3 could offer a strategy for enhancing the photosynthetic production of desired chemicals in cyanobacteria under specified conditions, the engineered target pathways have to be carefully selected to align with the intracellular redox balance of the cells.
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Affiliation(s)
- Kati Thiel
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turun Yliopisto, Finland
| | - Pekka Patrikainen
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turun Yliopisto, Finland
| | - Csaba Nagy
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turun Yliopisto, Finland
| | - Duncan Fitzpatrick
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turun Yliopisto, Finland
| | - Nicolas Pope
- Department of Future Technologies, University of Turku, 20014, Turun Yliopisto, Finland
| | - Eva-Mari Aro
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turun Yliopisto, Finland
| | - Pauli Kallio
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turun Yliopisto, Finland. .,, Itäinen Pitkäkatu 4 C, 20520, Turku, Finland.
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Pi K, Markelova E, Zhang P, Van Cappellen P. Arsenic Oxidation by Flavin-Derived Reactive Species under Oxic and Anoxic Conditions: Oxidant Formation and pH Dependence. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:10897-10905. [PMID: 31419125 DOI: 10.1021/acs.est.9b03188] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Flavins are ubiquitous redox-active compounds capable of producing reactive oxygen (O2•-, •OH, and H2O2) and flavin radical species in natural environments, yet their roles in the redox transformations of environmental contaminants, such as arsenic (As), remain to be investigated. Here, we show that reduced flavins can be a source of effective oxidants for As(III) under both oxic and anoxic conditions. For instance, in the presence of 15 μM reduced riboflavin (RBFH2), 22% of 30 μM As(III) is oxidized in aerated solution at pH 7.0. The co-oxidation of As(III) with RBFH2 is pH-dependent, with a faster reaction rate under mildly acidic relative to alkaline conditions. Quencher tests with 2-propanol (for •OH) and catalase (for H2O2) indicate that As(III) oxidation under oxic conditions is likely controlled by flavin-derived •OH at pH 5.2 and 7.0, and by H2O2 at pH 9.0. Kinetic modeling further implies that flavin-derived reactive oxygen species are mainly responsible for As(III) oxidation under oxic conditions, whereas oxidation of As(III) under anoxic conditions at pH 9.0 is attributed to riboflavin radicals (RBFH•) generated from co-existing oxidized and reduced riboflavin. The demonstrated ability of flavins to catalyze As(III) oxidation has potential implications for As redox cycling in the environment.
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Affiliation(s)
- Kunfu Pi
- Ecohydrology Research Group, Department of Earth and Environmental Sciences & Water Institute , University of Waterloo , N2L 3G1 Waterloo , Canada
| | | | - Peng Zhang
- State Key Laboratory of Biogeology and Environmental Geology , China University of Geosciences , 430074 Wuhan , China
| | - Philippe Van Cappellen
- Ecohydrology Research Group, Department of Earth and Environmental Sciences & Water Institute , University of Waterloo , N2L 3G1 Waterloo , Canada
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Hamilton TL. The trouble with oxygen: The ecophysiology of extant phototrophs and implications for the evolution of oxygenic photosynthesis. Free Radic Biol Med 2019; 140:233-249. [PMID: 31078729 DOI: 10.1016/j.freeradbiomed.2019.05.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 04/03/2019] [Accepted: 05/02/2019] [Indexed: 12/11/2022]
Abstract
The ability to harvest light to drive chemical reactions and gain energy provided microbes access to high energy electron donors which fueled primary productivity, biogeochemical cycles, and microbial evolution. Oxygenic photosynthesis is often cited as the most important microbial innovation-the emergence of oxygen-evolving photosynthesis, aided by geologic events, is credited with tipping the scale from a reducing early Earth to an oxygenated world that eventually lead to complex life. Anoxygenic photosynthesis predates oxygen-evolving photosynthesis and played a key role in developing and fine-tuning the photosystem architecture of modern oxygenic phototrophs. The release of oxygen as a by-product of metabolic activity would have caused oxidative damage to anaerobic microbiota that evolved under the anoxic, reducing conditions of early Earth. Photosynthetic machinery is particularly susceptible to the adverse effects of oxygen and reactive oxygen species and these effects are compounded by light. As a result, phototrophs employ additional detoxification mechanisms to mitigate oxidative stress and have evolved alternative oxygen-dependent enzymes for chlorophyll biosynthesis. Phylogenetic reconstruction studies and biochemical characterization suggest photosynthetic reactions centers, particularly in Cyanobacteria, evolved to both increase efficiency of electron transfer and avoid photodamage caused by chlorophyll radicals that is acute in the presence of oxygen. Here we review the oxygen and reactive oxygen species detoxification mechanisms observed in extant anoxygenic and oxygenic photosynthetic bacteria as well as the emergence of these mechanisms over evolutionary time. We examine the distribution of phototrophs in modern systems and phylogenetic reconstructions to evaluate the emergence of mechanisms to mediate oxidative damage and highlight changes in photosystems and reaction centers, chlorophyll biosynthesis, and niche space in response to oxygen production. This synthesis supports an emergence of H2S-driven anoxygenic photosynthesis in Cyanobacteria prior to the evolution of oxygenic photosynthesis and underscores a role for the former metabolism in fueling fine-tuning of the oxygen evolving complex and mechanisms to repair oxidative damage. In contrast, we note the lack of elaborate mechanisms to deal with oxygen in non-cyanobacterial anoxygenic phototrophs suggesting these microbes have occupied similar niche space throughout Earth's history.
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Affiliation(s)
- Trinity L Hamilton
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN, 55108, USA; Biotechnology Institute, University of Minnesota, St. Paul, MN, 55108, USA.
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