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Mantovani O, Haffner M, Walke P, Elshereef AA, Wagner B, Petras D, Forchhammer K, Selim KA, Hagemann M. The redox-sensitive R-loop of the carbon control protein SbtB contributes to the regulation of the cyanobacterial CCM. Sci Rep 2024; 14:7885. [PMID: 38570698 PMCID: PMC10991534 DOI: 10.1038/s41598-024-58354-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 03/28/2024] [Indexed: 04/05/2024] Open
Abstract
SbtB is a PII-like protein that regulates the carbon-concentrating mechanism (CCM) in cyanobacteria. SbtB proteins can bind many adenyl nucleotides and possess a characteristic C-terminal redox sensitive loop (R-loop) that forms a disulfide bridge in response to the diurnal state of the cell. SbtBs also possess an ATPase/ADPase activity that is modulated by the redox-state of the R-loop. To investigate the R-loop in the cyanobacterium Synechocystis sp. PCC 6803, site-specific mutants, unable to form the hairpin and permanently in the reduced state, and a R-loop truncation mutant, were characterized under different inorganic carbon (Ci) and light regimes. Growth under diurnal rhythm showed a role of the R-loop as sensor for acclimation to changing light conditions. The redox-state of the R-loop was found to impact the binding of the adenyl-nucleotides to SbtB, its membrane association and thereby the CCM regulation, while these phenotypes disappeared after truncation of the R-loop. Collectively, our data imply that the redox-sensitive R-loop provides an additional regulatory layer to SbtB, linking the CO2-related signaling activity of SbtB with the redox state of cells, mainly reporting the actual light conditions. This regulation not only coordinates CCM activity in the diurnal rhythm but also affects the primary carbon metabolism.
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Affiliation(s)
- Oliver Mantovani
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, A.-Einstein-Str. 3, 18059, Rostock, Germany
| | - Michael Haffner
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, Germany
| | - Peter Walke
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, A.-Einstein-Str. 3, 18059, Rostock, Germany
| | - Abdalla A Elshereef
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, Germany
- Chemistry of Natural and Microbial Products Department, Pharmaceutical and Drug Industries Research Institute, National Research Centre, Giza, Egypt
| | - Berenike Wagner
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, Germany
| | - Daniel Petras
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, Germany
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, Germany
| | - Khaled A Selim
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, Germany.
- Department of Protein Evolution, Max Planck Institute for Biology, Tübingen, Germany.
- Institute of Biology, Microbiology/Molecular Physiology of Prokaryotes, University of Freiburg, Schänzlestraße 1, 79104, Freiburg, Germany.
| | - Martin Hagemann
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, A.-Einstein-Str. 3, 18059, Rostock, Germany.
- Interdisciplinary Faculty, Department Life, Light and Matter, University of Rostock, Rostock, Germany.
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Timm S, Klaas N, Niemann J, Jahnke K, Alseekh S, Zhang Y, Souza PVL, Hou LY, Cosse M, Selinski J, Geigenberger P, Daloso DM, Fernie AR, Hagemann M. Thioredoxins o1 and h2 jointly adjust mitochondrial dihydrolipoamide dehydrogenase-dependent pathways towards changing environments. Plant Cell Environ 2024. [PMID: 38518065 DOI: 10.1111/pce.14899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 03/11/2024] [Accepted: 03/13/2024] [Indexed: 03/24/2024]
Abstract
Thioredoxins (TRXs) are central to redox regulation, modulating enzyme activities to adapt metabolism to environmental changes. Previous research emphasized mitochondrial and microsomal TRX o1 and h2 influence on mitochondrial metabolism, including photorespiration and the tricarboxylic acid (TCA) cycle. Our study aimed to compare TRX-based regulation circuits towards environmental cues mainly affecting photorespiration. Metabolite snapshots, phenotypes and CO2 assimilation were compared among single and multiple TRX mutants in the wild-type and the glycine decarboxylase T-protein knockdown (gldt1) background. Our analyses provided evidence for additive negative effects of combined TRX o1 and h2 deficiency on growth and photosynthesis. Especially metabolite accumulation patterns suggest a shared regulation mechanism mainly on mitochondrial dihydrolipoamide dehydrogenase (mtLPD1)-dependent pathways. Quantification of pyridine nucleotides, in conjunction with 13C-labelling approaches, and biochemical analysis of recombinant mtLPD1 supported this. It also revealed mtLPD1 inhibition by NADH, pointing at an additional measure to fine-tune it's activity. Collectively, we propose that lack of TRX o1 and h2 perturbs the mitochondrial redox state, which impacts on other pathways through shifts in the NADH/NAD+ ratio via mtLPD1. This regulation module might represent a node for simultaneous adjustments of photorespiration, the TCA cycle and branched chain amino acid degradation under fluctuating environmental conditions.
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Affiliation(s)
- Stefan Timm
- Plant Physiology Department, University of Rostock, Rostock, Germany
| | - Nicole Klaas
- Plant Physiology Department, University of Rostock, Rostock, Germany
| | - Janice Niemann
- Plant Physiology Department, University of Rostock, Rostock, Germany
| | - Kathrin Jahnke
- Plant Physiology Department, University of Rostock, Rostock, Germany
| | - Saleh Alseekh
- Max Planck Institute of Molecular Plant Physiology, Golm, Germany
| | - Youjun Zhang
- Max Planck Institute of Molecular Plant Physiology, Golm, Germany
- Center of Plant System Biology and Biotechnology, Plovdiv, Bulgaria
| | - Paulo V L Souza
- LabPlant, Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza, Brazil
| | - Liang-Yu Hou
- Department Biology I, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Maike Cosse
- Department of Plant Cell Biology, Botanical Institute, Christian-Albrechts University Kiel, Kiel, Germany
| | - Jennifer Selinski
- Department of Plant Cell Biology, Botanical Institute, Christian-Albrechts University Kiel, Kiel, Germany
| | - Peter Geigenberger
- Department Biology I, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
| | - Danilo M Daloso
- LabPlant, Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza, Brazil
| | - Alisdair R Fernie
- Max Planck Institute of Molecular Plant Physiology, Golm, Germany
- Center of Plant System Biology and Biotechnology, Plovdiv, Bulgaria
| | - Martin Hagemann
- Plant Physiology Department, University of Rostock, Rostock, Germany
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Heise CM, Hagemann M, Schubert H. Photosynthetic response of Chara braunii towards different bicarbonate concentrations. Physiol Plant 2024; 176:e14234. [PMID: 38439180 DOI: 10.1111/ppl.14234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 02/11/2024] [Accepted: 02/15/2024] [Indexed: 03/06/2024]
Abstract
A variety of inorganic carbon acquisition modes have been proposed in Characean algae, however, a broadly applicable inorganic carbon uptake mechanism is unknown for the genus Chara. In the present study, we analyzed if C. braunii can efficiently use HCO3 - as a carbon source for photosynthesis. For this purpose, C. braunii was exposed to different concentrations of NaHCO3 - at different time scales. The photosynthetic electron transport through photosystem I (PSI) and II (PSII), the maximum electron transport rate (ETRmax ), the efficiency of the electron transport rate (α, the initial slope of the ETR), and the light saturation point of photosynthesis (Ek ) were evaluated. Additionally, pigment contents (chlorophyll a, chlorophyll b, and carotenoids) were determined. Bicarbonate addition positively affected ETRmax , after direct HCO3 - application, of both PSII and PSI, but this effect seems to decrease after 1 h and 24 h. Similar trends were seen for Ek , but no significant effect was observed for α. Pigment contents showed no significant changes in relation to different HCO3 - concentrations. To evaluate if cyclic electron flow around PSI was involved in active HCO3 - uptake, the ratio of PSI ETRmax /PSII ETRmax was calculated but did not show a distinctive trend. These results suggest that C. braunii can utilize NaHCO3 - in short-term periods as a carbon source but could rely on other carbon acquisition mechanisms over prolonged time periods. These observations suggest that the minor role of HCO3 - as a carbon source for photosynthesis in this alga might differentiate C. braunii from other examined Chara spp.
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Affiliation(s)
- Carolin Magdalene Heise
- Institute of Biosciences, Department of Aquatic Ecology, University of Rostock, Rostock, Germany
- Institute of Biosciences, Department of Plant Physiology, University of Rostock, Rostock, Germany
| | - Martin Hagemann
- Institute of Biosciences, Department of Plant Physiology, University of Rostock, Rostock, Germany
| | - Hendrik Schubert
- Institute of Biosciences, Department of Aquatic Ecology, University of Rostock, Rostock, Germany
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Kraus A, Spät P, Timm S, Wilson A, Schumann R, Hagemann M, Maček B, Hess WR. Protein NirP1 regulates nitrite reductase and nitrite excretion in cyanobacteria. Nat Commun 2024; 15:1911. [PMID: 38429292 PMCID: PMC10907346 DOI: 10.1038/s41467-024-46253-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 02/19/2024] [Indexed: 03/03/2024] Open
Abstract
When the supply of inorganic carbon is limiting, photosynthetic cyanobacteria excrete nitrite, a toxic intermediate in the ammonia assimilation pathway from nitrate. It has been hypothesized that the excreted nitrite represents excess nitrogen that cannot be further assimilated due to the missing carbon, but the underlying molecular mechanisms are unclear. Here, we identified a protein that interacts with nitrite reductase, regulates nitrogen metabolism and promotes nitrite excretion. The protein, which we named NirP1, is encoded by an unannotated gene that is upregulated under low carbon conditions and controlled by transcription factor NtcA, a central regulator of nitrogen homeostasis. Ectopic overexpression of nirP1 in Synechocystis sp. PCC 6803 resulted in a chlorotic phenotype, delayed growth, severe changes in amino acid pools, and nitrite excretion. Coimmunoprecipitation experiments indicated that NirP1 interacts with nitrite reductase, a central enzyme in the assimilation of ammonia from nitrate/nitrite. Our results reveal that NirP1 is widely conserved in cyanobacteria and plays a crucial role in the coordination of C/N primary metabolism by targeting nitrite reductase.
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Affiliation(s)
- Alexander Kraus
- Genetics and Experimental Bioinformatics, Faculty of Biology, Freiburg University, D-79104, Freiburg, Germany
| | - Philipp Spät
- Department of Quantitative Proteomics, Interfaculty Institute for Cell Biology, University of Tübingen, D-72076, Tübingen, Germany
| | - Stefan Timm
- Plant Physiology Department, Institute of Biosciences, University of Rostock, D-18059, Rostock, Germany
| | - Amy Wilson
- Genetics and Experimental Bioinformatics, Faculty of Biology, Freiburg University, D-79104, Freiburg, Germany
| | - Rhena Schumann
- Biological Station Zingst, University of Rostock, D-18374, Zingst, Germany
| | - Martin Hagemann
- Plant Physiology Department, Institute of Biosciences, University of Rostock, D-18059, Rostock, Germany
| | - Boris Maček
- Department of Quantitative Proteomics, Interfaculty Institute for Cell Biology, University of Tübingen, D-72076, Tübingen, Germany
| | - Wolfgang R Hess
- Genetics and Experimental Bioinformatics, Faculty of Biology, Freiburg University, D-79104, Freiburg, Germany.
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Barske T, Spät P, Schubert H, Walke P, Maček B, Hagemann M. The Role of Serine/Threonine-Specific Protein Kinases in Cyanobacteria - SpkB Is Involved in Acclimation to Fluctuating Conditions in Synechocystis sp. PCC 6803. Mol Cell Proteomics 2023; 22:100656. [PMID: 37797745 PMCID: PMC10651672 DOI: 10.1016/j.mcpro.2023.100656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 08/31/2023] [Accepted: 10/01/2023] [Indexed: 10/07/2023] Open
Abstract
Protein phosphorylation via serine/threonine protein kinases (Spk) is a widespread mechanism to adjust cellular processes toward changing environmental conditions. To study their role(s) in cyanobacteria, we investigated a collection of 11 completely segregated spk mutants among the 12 annotated Spks in the model cyanobacterium Synechocystis sp. PCC 6803. Screening of the mutant collection revealed that especially the mutant defective in SpkB encoded by slr1697 showed clear deviations regarding carbon metabolism, that is, reduced growth rates at low CO2 or in the presence of glucose, and different glycogen accumulation patterns compared to WT. Alterations in the proteome of ΔspkB indicated changes of the cell surface but also metabolic functions. A phospho-proteome analysis revealed the absence of any phosphorylation in two proteins, while decreased phosphorylation of the carboxysome-associated protein CcmM and increased phosphorylation of the allophycocyanin alpha subunit ApcA was detected in ΔspkB. Furthermore, the regulatory PII protein appeared less phosphorylated in the mutant compared to WT, which was verified in Western blot experiments, indicating a clearly delayed PII phosphorylation in cells shifted from nitrate-containing to nitrate-free medium. Our results indicate that SpkB is an important regulator in Synechocystis that is involved in phosphorylation of the PII protein and additional proteins.
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Affiliation(s)
- Thomas Barske
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, Germany
| | - Philipp Spät
- Department of Organismic Interactions, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, Germany; Department of Quantitative Proteomics, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, Germany
| | - Hendrik Schubert
- Department of Aquatic Ecology, Institute of Biosciences, University of Rostock, Rostock, Germany
| | - Peter Walke
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, Germany
| | - Boris Maček
- Department of Quantitative Proteomics, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, Germany
| | - Martin Hagemann
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, Germany; Interdisciplinary Faculty, Department Life, Light and Matter, University of Rostock, Rostock, Germany.
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Heß D, Heise CM, Schubert H, Hess WR, Hagemann M. The impact of salt stress on the physiology and the transcriptome of the model streptophyte green alga Chara braunii. Physiol Plant 2023; 175:e14123. [PMID: 38148211 DOI: 10.1111/ppl.14123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/29/2023] [Accepted: 12/05/2023] [Indexed: 12/28/2023]
Abstract
Chara braunii is a model for early land plant evolution and terrestrialization. Salt stress has a profound effect on water and ion transport activities, thereby interacting with many other processes, including inorganic carbon acquisition for photosynthesis. In this study, we analyzed the impact of salt stress (5 practical salt units, PSU) on the physiology and gene expression in C. braunii. Photosynthesis was only slightly affected 6 h after salt addition and returned to control levels after 48 h. Several organic compounds such as proline, glutamate, sucrose, and 2-aminobutyrate accumulated in salt-treated thalli and might contribute to osmotic potential acclimation, whereas the amount of K+ decreased. We quantified transcript levels for 17,387 genes, of which 95 were up-regulated and 44 down-regulated after salt addition. Genes encoding proteins of the functional groups ion/solute transport and cell wall synthesis/modulation were enriched among the up-regulated genes 24-48 h after salt stress, indicating their role in osmotic acclimation. However, a homolog to land plant ERD4 osmosensors was transiently upregulated after 6 h, and phylogenetic analyses suggested that these sensors evolved in Charophyceae. Down-regulated genes were mainly related to photosynthesis and carbon metabolism/fixation, consistent with the observed lowered growth after extended cultivation. The changed expression of genes encoding proteins for inorganic carbon acquisition might be related to the impact of salt on ionic relations and inorganic carbon uptake. The results indicate that C. braunii can tolerate enhanced salt concentrations in a defined acclimation process, including distinct gene expression changes to achieve new metabolic homeostasis.
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Affiliation(s)
- Daniel Heß
- Genetics and Experimental Bioinformatics Group, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Carolin M Heise
- Plant Physiology Department, Faculty of Mathematics and Natural Sciences, University of Rostock, Rostock, Germany
- Aquatic Ecology Department, Faculty of Mathematics and Natural Sciences, University of Rostock, Rostock, Germany
| | - Hendrik Schubert
- Aquatic Ecology Department, Faculty of Mathematics and Natural Sciences, University of Rostock, Rostock, Germany
| | - Wolfgang R Hess
- Genetics and Experimental Bioinformatics Group, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Martin Hagemann
- Plant Physiology Department, Faculty of Mathematics and Natural Sciences, University of Rostock, Rostock, Germany
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Böhm J, Kauss K, Michl K, Engelhardt L, Brouwer EM, Hagemann M. Impact of the carbon flux regulator protein pirC on ethanol production in engineered cyanobacteria. Front Microbiol 2023; 14:1238737. [PMID: 37649635 PMCID: PMC10465007 DOI: 10.3389/fmicb.2023.1238737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 08/04/2023] [Indexed: 09/01/2023] Open
Abstract
Future sustainable energy production can be achieved using mass cultures of photoautotrophic microorganisms such as cyanobacteria, which are engineered to synthesize valuable products directly from CO2 and sunlight. For example, strains of the model organism Synechocystis sp. PCC 6803 have been generated to produce ethanol. Here, we performed a study to prove the hypothesis that carbon flux in the direction of pyruvate is one bottleneck to achieve high ethanol titers in cyanobacteria. Ethanol-producing strains of the cyanobacterium Synechocystis sp. PCC 6803 were generated that bear mutation in the gene pirC aiming to increase carbon flux towards pyruvate. The strains were cultivated at different nitrogen or carbon conditions and the ethanol production was analysed. Generally, a clear correlation between growth rate and ethanol production was found. The mutation of pirC, however, had only a positive impact on ethanol titers under nitrogen depletion. The increase in ethanol was accompanied by elevated pyruvate and lowered glycogen levels indicating that the absence of pirC indeed increased carbon partitioning towards lower glycolysis. Metabolome analysis revealed that this change in carbon flow had also a marked impact on the overall primary metabolism in Synechocystis sp. PCC 6803. Deletion of pirC improved ethanol production under specific conditions supporting the notion that a better understanding of regulatory mechanisms involved in cyanobacterial carbon partitioning is needed to engineer more productive cyanobacterial strains.
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Affiliation(s)
- Julien Böhm
- Department Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, Germany
- Department Aquatic Ecology, Institute of Biosciences, University of Rostock, Rostock, Germany
| | - Karsten Kauss
- Department Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, Germany
| | - Klaudia Michl
- Department Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, Germany
| | - Lisa Engelhardt
- Department Microbiology, Institute of Biosciences, University of Rostock, Rostock, Germany
| | - Eva-Maria Brouwer
- Department Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, Germany
| | - Martin Hagemann
- Department Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, Germany
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Lu X, Hagemann M, Liu J, Shukla P, Tan X. Editorial: Engineering microalgal chassis cells. Front Microbiol 2023; 14:1237999. [PMID: 37434705 PMCID: PMC10332849 DOI: 10.3389/fmicb.2023.1237999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Accepted: 06/16/2023] [Indexed: 07/13/2023] Open
Affiliation(s)
- Xuefeng Lu
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences (CAS), Qingdao, China
| | - Martin Hagemann
- Institute of Biosciences, Department of Plant Physiology, University of Rostock, Rostock, Germany
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, China
| | - Pratyoosh Shukla
- Enzyme Technology and Protein Bioinformatics Laboratory, School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Xiaoming Tan
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
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Alvarenga-Lucius L, Linhartová M, Schubert H, Maaß S, Becher D, Hess WR, Sobotka R, Hagemann M. The high-light-induced protein SliP4 binds to NDH1 and photosystems facilitating cyclic electron transport and state transition in Synechocystis sp. PCC 6803. New Phytol 2023. [PMID: 37282607 DOI: 10.1111/nph.18987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 05/01/2023] [Indexed: 06/08/2023]
Abstract
An increasing number of small proteins has been identified in the genomes of well-annotated organisms, including the model cyanobacterium Synechocystis sp. PCC 6803. We describe a newly assigned protein comprising 37 amino acids that is encoded upstream of the superoxide dismutase SodB encoding gene. To clarify the role of SliP4, we analyzed a Synechocystis sliP4 mutant and a strain containing a fully active, Flag-tagged variant of SliP4 (SliP4.f). The initial hypothesis that this small protein might be functionally related to SodB could not be supported. Instead, we provide evidence that it fulfills important functions related to the organization of photosynthetic complexes. Therefore, we named it a small light-induced protein of 4 kDa, SliP4. This protein is strongly induced under high-light conditions. The lack of SliP4 causes a light-sensitive phenotype due to impaired cyclic electron flow and state transitions. Interestingly, SliP4.f was co-isolated with NDH1 complex and both photosystems. The interaction between SliP4.f and all three types of complexes was further confirmed by additional pulldowns and 2D-electrophoreses. We propose that the dimeric SliP4 serves as a molecular glue promoting the aggregation of thylakoid complexes, which contributes to different electron transfer modes and energy dissipation under stress conditions.
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Affiliation(s)
- Luna Alvarenga-Lucius
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, D-18059, Rostock, Germany
| | - Markéta Linhartová
- Institute of Microbiology of the Czech Academy of Sciences, Opatovický mlýn, Třeboň, 379 01, Czech Republic
| | - Hendrik Schubert
- Department of Aquatic Ecology, Institute of Biosciences, University of Rostock, D-18059, Rostock, Germany
| | - Sandra Maaß
- Department of Microbial Proteomics, Institute of Microbiology, University of Greifswald, D-17489, Greifswald, Germany
| | - Dörte Becher
- Department of Microbial Proteomics, Institute of Microbiology, University of Greifswald, D-17489, Greifswald, Germany
| | - Wolfgang R Hess
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Schänzlestr. 1, D-79104, Freiburg, Germany
| | - Roman Sobotka
- Institute of Microbiology of the Czech Academy of Sciences, Opatovický mlýn, Třeboň, 379 01, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, 370 05, Czech Republic
| | - Martin Hagemann
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, D-18059, Rostock, Germany
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Mantovani O, Haffner M, Selim KA, Hagemann M, Forchhammer K. Roles of second messengers in the regulation of cyanobacterial physiology: the carbon-concentrating mechanism and beyond. Microlife 2023; 4:uqad008. [PMID: 37223741 PMCID: PMC10117731 DOI: 10.1093/femsml/uqad008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/09/2023] [Accepted: 02/22/2023] [Indexed: 05/25/2023]
Abstract
Second messengers are a fundamental category of small molecules and ions that are involved in the regulation of many processes in all domains of life. Here we focus on cyanobacteria, prokaryotes playing important roles as primary producers in the geochemical cycles due to their capability of oxygenic photosynthesis and carbon and nitrogen fixation. Of particular interest is the inorganic carbon-concentrating mechanism (CCM), which allows cyanobacteria to concentrate CO2 near RubisCO. This mechanism needs to acclimate toward fluctuating conditions, such as inorganic carbon availability, intracellular energy levels, diurnal light cycle, light intensity, nitrogen availability, and redox state of the cell. During acclimation to such changing conditions, second messengers play a crucial role, particularly important is their interaction with the carbon control protein SbtB, a member of the PII regulator protein superfamily. SbtB is capable of binding several second messengers, uniquely adenyl nucleotides, to interact with different partners in a variety of responses. The main identified interaction partner is the bicarbonate transporter SbtA, which is regulated via SbtB depending on the energy state of the cell, the light conditions, and different CO2 availability, including cAMP signaling. The interaction with the glycogen branching enzyme, GlgB, showed a role for SbtB in the c-di-AMP-dependent regulation of glycogen synthesis during the diurnal life cycle of cyanobacteria. SbtB has also been shown to impact gene expression and metabolism during acclimation to changing CO2 conditions. This review summarizes the current knowledge about the complex second messenger regulatory network in cyanobacteria, with emphasis on carbon metabolism.
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Affiliation(s)
- Oliver Mantovani
- Institute of Biosciences, Department of Plant Physiology, University of Rostock, D-18059 Rostock, Germany
| | - Michael Haffner
- Interfaculty Institute of Microbiology and Infection Medicine, Organismic Interactions Department, Cluster of Excellence ‘Controlling Microbes to Fight Infections’, Tübingen University, D-72076 Tübingen, Germany
| | - Khaled A Selim
- Interfaculty Institute for Microbiology and Infection Medicine, Organismic Interactions Department, Tübingen University, Auf der Morgenstelle 28, D-72076 Tübingen, Germany. E-mail:
| | - Martin Hagemann
- Institut für Biowissenschaften, Abteilung Pflanzenphysiologie, Universität Rostock, A.-Einstein-Str. 3, Rostock D-18059, Germany. E-mail:
| | - Karl Forchhammer
- Corresponding author. Interfaculty Institute for Microbiology and Infection Medicine, Organismic Interactions Department, Tübingen University, Auf der Morgenstelle 28, D-72076 Tübingen, Germany. E-mail:
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Selim KA, Haffner M, Mantovani O, Albrecht R, Zhu H, Hagemann M, Forchhammer K, Hartmann MD. Carbon signaling protein SbtB possesses atypical redox-regulated apyrase activity to facilitate regulation of bicarbonate transporter SbtA. Proc Natl Acad Sci U S A 2023; 120:e2205882120. [PMID: 36800386 PMCID: PMC9974498 DOI: 10.1073/pnas.2205882120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 12/15/2022] [Indexed: 02/18/2023] Open
Abstract
The PII superfamily consists of widespread signal transduction proteins found in all domains of life. In addition to canonical PII proteins involved in C/N sensing, structurally similar PII-like proteins evolved to fulfill diverse, yet poorly understood cellular functions. In cyanobacteria, the bicarbonate transporter SbtA is co-transcribed with the conserved PII-like protein, SbtB, to augment intracellular inorganic carbon levels for efficient CO2 fixation. We identified SbtB as a sensor of various adenine nucleotides including the second messenger nucleotides cyclic AMP (cAMP) and c-di-AMP. Moreover, many SbtB proteins possess a C-terminal extension with a disulfide bridge of potential redox-regulatory function, which we call R-loop. Here, we reveal an unusual ATP/ADP apyrase (diphosphohydrolase) activity of SbtB that is controlled by the R-loop. We followed the sequence of hydrolysis reactions from ATP over ADP to AMP in crystallographic snapshots and unravel the structural mechanism by which changes of the R-loop redox state modulate apyrase activity. We further gathered evidence that this redox state is controlled by thioredoxin, suggesting that it is generally linked to cellular metabolism, which is supported by physiological alterations in site-specific mutants of the SbtB protein. Finally, we present a refined model of how SbtB regulates SbtA activity, in which both the apyrase activity and its redox regulation play a central role. This highlights SbtB as a central switch point in cyanobacterial cell physiology, integrating not only signals from the energy state (adenyl-nucleotide binding) and the carbon supply via cAMP binding but also from the day/night status reported by the C-terminal redox switch.
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Affiliation(s)
- Khaled A. Selim
- Interfaculty Institute of Microbiology and Infection Medicine, Organismic Interactions Department, Cluster of Excellence 'Controlling Microbes to Fight Infections', Tübingen University, 72076Tübingen, Germany
- Department of Protein Evolution, Max Planck Institute for Biology, 72076Tübingen, Germany
| | - Michael Haffner
- Interfaculty Institute of Microbiology and Infection Medicine, Organismic Interactions Department, Cluster of Excellence 'Controlling Microbes to Fight Infections', Tübingen University, 72076Tübingen, Germany
| | - Oliver Mantovani
- Plant Physiology Department, Institute of Biological Sciences, Rostock University, 18059Rostock, Germany
| | - Reinhard Albrecht
- Department of Protein Evolution, Max Planck Institute for Biology, 72076Tübingen, Germany
| | - Hongbo Zhu
- Department of Protein Evolution, Max Planck Institute for Biology, 72076Tübingen, Germany
| | - Martin Hagemann
- Plant Physiology Department, Institute of Biological Sciences, Rostock University, 18059Rostock, Germany
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine, Organismic Interactions Department, Cluster of Excellence 'Controlling Microbes to Fight Infections', Tübingen University, 72076Tübingen, Germany
| | - Marcus D. Hartmann
- Department of Protein Evolution, Max Planck Institute for Biology, 72076Tübingen, Germany
- Interfaculty Institute of Biochemistry, Tübingen University, 72076Tübingen, Germany
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12
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Santoro M, Hassenrück C, Labrenz M, Hagemann M. Acclimation of Nodularia spumigena CCY9414 to inorganic phosphate limitation - Identification of the P-limitation stimulon via RNA-seq. Front Microbiol 2023; 13:1082763. [PMID: 36687591 PMCID: PMC9846622 DOI: 10.3389/fmicb.2022.1082763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 12/05/2022] [Indexed: 01/06/2023] Open
Abstract
Nodularia spumigena is a toxic, filamentous cyanobacterium capable of fixing atmospheric N2, which is often dominating cyanobacterial bloom events in the Baltic Sea and other brackish water systems worldwide. Increasing phosphate limitation has been considered as one environmental factor promoting cyanobacterial mass developments. In the present study, we analyzed the response of N. spumigena strain CCY9414 toward strong phosphate limitation. Growth of the strain was diminished under P-deplete conditions; however, filaments contained more polyphosphate under P-deplete compared to P-replete conditions. Using RNA-seq, gene expression was compared in N. spumigena CCY9414 after 7 and 14 days in P-deplete and P-replete conditions, respectively. After 7 days, 112 genes were significantly up-regulated in P-deplete filaments, among them was a high proportion of genes encoding proteins related to P-homeostasis such as transport systems for different P species. Many of these genes became also up-regulated after 14 days compared to 7 days in filaments grown under P-replete conditions, which was consistent with the almost complete consumption of dissolved P in these cultures after 14 days. In addition to genes directly related to P starvation, genes encoding proteins for bioactive compound synthesis, gas vesicles formation, or sugar catabolism were stimulated under P-deplete conditions. Collectively, our data describe an experimentally validated P-stimulon in N. spumigena CCY9414 and provide the indication that severe P limitation could indeed support bloom formation by this filamentous strain.
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Affiliation(s)
- Mariano Santoro
- Department of Biological Oceanography, Leibniz Institute for Baltic Sea Research, Warnemünde (IOW), Rostock, Germany,Department of Plant Physiology, Institute for Biosciences, University of Rostock, Rostock, Germany
| | - Christiane Hassenrück
- Department of Biological Oceanography, Leibniz Institute for Baltic Sea Research, Warnemünde (IOW), Rostock, Germany
| | - Matthias Labrenz
- Department of Biological Oceanography, Leibniz Institute for Baltic Sea Research, Warnemünde (IOW), Rostock, Germany
| | - Martin Hagemann
- Department of Plant Physiology, Institute for Biosciences, University of Rostock, Rostock, Germany,*Correspondence: Martin Hagemann,
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13
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Lucius S, Theune M, Arrivault S, Hildebrandt S, Mullineaux CW, Gutekunst K, Hagemann M. CP12 fine-tunes the Calvin-Benson cycle and carbohydrate metabolism in cyanobacteria. Front Plant Sci 2022; 13:1028794. [PMID: 36330266 PMCID: PMC9623430 DOI: 10.3389/fpls.2022.1028794] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 09/26/2022] [Indexed: 06/12/2023]
Abstract
The regulatory protein CP12 can bind glyceraldehyde 3-phosphate dehydrogenase (GapDH) and phosphoribulokinase (PRK) in oxygenic phototrophs, thereby switching on and off the flux through the Calvin-Benson cycle (CBC) under light and dark conditions, respectively. However, it can be assumed that CP12 is also regulating CBC flux under further conditions associated with redox changes. To prove this hypothesis, the mutant Δcp12 of the model cyanobacterium Synechocystis sp. PCC 6803 was compared to wild type and different complementation strains. Fluorescence microscopy showed for the first time the in vivo kinetics of assembly and disassembly of the CP12-GapDH-PRK complex, which was absent in the mutant Δcp12. Metabolome analysis revealed differences in the contents of ribulose 1,5-bisphosphate and dihydroxyacetone phosphate, the products of the CP12-regulated enzymes GapDH and PRK, between wild type and mutant Δcp12 under changing CO2 conditions. Growth of Δcp12 was not affected at constant light under different inorganic carbon conditions, however, the addition of glucose inhibited growth in darkness as well as under diurnal conditions. The growth defect in the presence of glucose is associated with the inability of Δcp12 to utilize external glucose. These phenotypes could be complemented by ectopic expression of the native CP12 protein, however, expression of CP12 variants with missing redox-sensitive cysteine pairs only partly restored the growth with glucose. These experiments indicated that the loss of GapDH-inhibition via CP12 is more critical than PRK association. Measurements of the NAD(P)H oxidation revealed an impairment of light intensity-dependent redox state regulation in Δcp12. Collectively, our results indicate that CP12-dependent regulation of the CBC is crucial for metabolic adjustment under conditions leading to redox changes such as diurnal conditions, glucose addition, and different CO2 conditions in cyanobacteria.
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Affiliation(s)
- Stefan Lucius
- Department Plant Physiology, University Rostock, Rostock, Germany
| | - Marius Theune
- Molecular Plant Physiology, Bioenergetics in Photoautotrophs, University Kassel, Kassel, Germany
- Botanical Institute, University Kiel, Kiel, Germany
| | - Stéphanie Arrivault
- Max Planck Institute of Molecular Plant Physiology, Emeritus Group System Regulation, Potsdam, Germany
| | | | - Conrad W. Mullineaux
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
| | - Kirstin Gutekunst
- Molecular Plant Physiology, Bioenergetics in Photoautotrophs, University Kassel, Kassel, Germany
- Botanical Institute, University Kiel, Kiel, Germany
| | - Martin Hagemann
- Department Plant Physiology, University Rostock, Rostock, Germany
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14
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Song K, Hagemann M, Georg J, Maaß S, Becher D, Hess WR. Expression of the Cyanobacterial F oF 1 ATP Synthase Regulator AtpΘ Depends on Small DNA-Binding Proteins and Differential mRNA Stability. Microbiol Spectr 2022; 10:e0256221. [PMID: 35446123 PMCID: PMC9241938 DOI: 10.1128/spectrum.02562-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 03/19/2022] [Indexed: 11/20/2022] Open
Abstract
FoF1 ATP synthases produce ATP, the universal biological energy source. ATP synthase complexes on cyanobacterial thylakoid membranes use proton gradients generated either by photosynthesis or respiration. AtpΘ is an ATP synthase regulator in cyanobacteria which is encoded by the gene atpT. AtpΘ prevents the hydrolysis of ATP (reverse reaction) that otherwise would occur under unfavorable conditions. In the cyanobacterium Synechocystis sp. PCC 6803, AtpΘ is expressed maximum in darkness but at very low levels under optimum phototrophic growth conditions or in the presence of glucose. DNA coimmunoprecipitation experiments followed by mass spectrometry identified the binding of the two transcriptional regulators cyAbrB1 and cyAbrB2 to the promoter and the histone-like protein HU to the 5'UTR of atpT. Analyses of nucleotide substitutions in the promoter and GFP reporter assays identified a functionally relevant sequence motif resembling the HLR1 element bound by the RpaB transcription factor. Electrophoretic mobility shift assays confirmed interaction of cyAbrB1, cyAbrB2, and RpaB with the promoter DNA. However, overall the effect of transcriptional regulation was comparatively low. In contrast, atpT transcript stabilities differed dramatically, half-lives were 1.6 min in the light, 33 min in the dark and substantial changes were observed if glucose or DCMU were added. These findings show that transcriptional control of atpT involves nucleoid-associated DNA-binding proteins, positive regulation through RpaB, while the major effect on the condition-dependent regulation of atpT expression is mediated by controlling mRNA stability, which is related to the cellular redox and energy status. IMPORTANCE FoF1 ATP synthases produce ATP, the universal biological energy source. Under unfavorable conditions, ATP synthases can operate in a futile reverse reaction, pumping protons while ATP is used up. Cyanobacteria perform plant-like photosynthesis, but they cannot use the same mechanism as plant chloroplasts to inhibit ATP synthases during the night because respiratory and photosynthetic complexes are both located in the same membrane system. AtpΘ is a small protein encoded by the gene atpT in cyanobacteria that can prevent the ATP synthase reverse reaction (ATPase activity). Here we found that three transcription factors contribute to the regulation of atpT expression. However, the control of mRNA stability was identified as the major regulatory process governing atpT expression. Thus, it is the interplay between transcriptional and posttranscriptional regulation that position the AtpΘ-based regulatory mechanism within the context of the cellular redox and energy balance.
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Affiliation(s)
- Kuo Song
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Martin Hagemann
- Plant Physiology Department, Institute of Biological Sciences, University of Rostock, Rostock, Germany
| | - Jens Georg
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Sandra Maaß
- Department of Microbial Proteomics, Institute of Microbiology, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Dörte Becher
- Department of Microbial Proteomics, Institute of Microbiology, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Wolfgang R. Hess
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Freiburg, Germany
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15
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Mantovani O, Reimann V, Haffner M, Herrmann FP, Selim KA, Forchhammer K, Hess WR, Hagemann M. The impact of the cyanobacterial carbon-regulator protein SbtB and of the second messengers cAMP and c-di-AMP on CO 2 -dependent gene expression. New Phytol 2022; 234:1801-1816. [PMID: 35285042 DOI: 10.1111/nph.18094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
The amount of inorganic carbon (Ci ) fluctuates in aquatic environments. Cyanobacteria evolved a Ci -concentrating mechanism (CCM) that is regulated at different levels. The regulator SbtB binds to the second messengers cAMP or c-di-AMP and is involved in acclimation to low Ci (LC) in Synechocystis sp. PCC 6803. Here, we investigated the role of SbtB and of associated second messengers at different Ci conditions. The transcriptome of wild-type (WT) Synechocystis and the ΔsbtB mutant were compared with Δcya1, a mutant defective in cAMP production, and ΔdacA, a mutant defective in generating c-di-AMP. A defined subset of LC-regulated genes in the WT was already changed in ΔsbtB under high Ci (HC) conditions. This response of ΔsbtB correlated with a diminished induction of many CCM-associated genes after LC shift in this mutant. The Δcya1 mutant showed less deviation from WT, whereas ΔdacA induced CCM-associated genes under HC. Metabolome analysis also revealed differences between the strains, whereby ΔsbtB showed slower accumulation of 2-phosphoglycolate and ΔdacA differences among amino acids compared to WT. Collectively, these results indicate that SbtB regulates a subset of LC acclimation genes while c-di-AMP and especially cAMP appear to have a lesser impact on gene expression under different Ci availabilities.
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Affiliation(s)
- Oliver Mantovani
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, D-18059, Germany
| | - Viktoria Reimann
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Freiburg, D-79104, Germany
| | - Michael Haffner
- Department of Organismic Interactions, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, D-72076, Germany
| | - Felix Philipp Herrmann
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, D-18059, Germany
| | - Khaled A Selim
- Department of Organismic Interactions, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, D-72076, Germany
| | - Karl Forchhammer
- Department of Organismic Interactions, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, D-72076, Germany
| | - Wolfgang R Hess
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Freiburg, D-79104, Germany
| | - Martin Hagemann
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, D-18059, Germany
- Department Life, Light and Matter, Interdisciplinary Faculty, University of Rostock, Rostock, D-18059, Germany
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16
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Bantu L, Chauhan S, Srikumar A, Hirakawa Y, Suzuki I, Hagemann M, Prakash JSS. A membrane-bound cAMP receptor protein, SyCRP1 mediates inorganic carbon response in Synechocystis sp. PCC 6803. Biochim Biophys Acta Gene Regul Mech 2022; 1865:194803. [PMID: 35272049 DOI: 10.1016/j.bbagrm.2022.194803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 02/24/2022] [Accepted: 02/27/2022] [Indexed: 06/14/2023]
Abstract
The availability of inorganic carbon (Ci) as the source for photosynthesis is fluctuating in aquatic environments. Despite the involvement of transcriptional regulators CmpR and NdhR in regulating genes encoding Ci transporters at limiting CO2, the Ci-sensing mechanism is largely unknown among cyanobacteria. Here we report that a cAMP-dependent transcription factor SyCRP1 mediates Ci response in Synechocystis. The mutant ∆sycrp1 exhibited a slow-growth phenotype and reduced maximum rate of bicarbonate-dependent photosynthetic electron transport (Vmax) compared to wild-type at the scarcity of CO2. The number of carboxysomes was decreased significantly in the ∆sycrp1 at low CO2 consistent with its reduced Vmax. The DNA microarray analysis revealed the upregulation of genes encoding Ci transporters in ∆sycrp1. The membrane-localized SyCRP1 was released into the cytosol in wild-type cells shifted from low to high CO2 or upon cAMP treatment. Soluble His-tagged SyCRP1 was shown to target DNA-binding sites upstream of the Ci-regulated genes sbtA and ccmK3. In addition, cAMP enhanced the binding of SyCRP1 to its target sites. Our data collectively suggest that the Ci is sensed through the second messenger cAMP releasing membrane-bound SyCRP1 into cytoplasm under sufficient CO2 conditions. Hence, SyCRP1 is a possible regulator of carbon concentrating mechanism, and such a regulation might be mediated via sensing Ci levels through cAMP in Synechocystis.
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Affiliation(s)
- Lingaswamy Bantu
- From the Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Suraj Chauhan
- From the Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Afshan Srikumar
- From the Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Yoshihisa Hirakawa
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba 305-8572, Japan
| | - Iwane Suzuki
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba 305-8572, Japan
| | - Martin Hagemann
- Plant Physiology Department, Institute of Biological Sciences, University of Rostock, Albert-Einstein-Str. 3, D-18059 Rostock, Germany
| | - Jogadhenu S S Prakash
- From the Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
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17
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Wang Y, Chen X, Spengler K, Terberger K, Boehm M, Appel J, Barske T, Timm S, Battchikova N, Hagemann M, Gutekunst K. Pyruvate:ferredoxin oxidoreductase and low abundant ferredoxins support aerobic photomixotrophic growth in cyanobacteria. eLife 2022; 11:71339. [PMID: 35138247 PMCID: PMC8887894 DOI: 10.7554/elife.71339] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 02/06/2022] [Indexed: 11/24/2022] Open
Abstract
The decarboxylation of pyruvate is a central reaction in the carbon metabolism of all organisms. It is catalyzed by the pyruvate:ferredoxin oxidoreductase (PFOR) and the pyruvate dehydrogenase (PDH) complex. Whereas PFOR reduces ferredoxin, the PDH complex utilizes NAD+. Anaerobes rely on PFOR, which was replaced during evolution by the PDH complex found in aerobes. Cyanobacteria possess both enzyme systems. Our data challenge the view that PFOR is exclusively utilized for fermentation. Instead, we show, that the cyanobacterial PFOR is stable in the presence of oxygen in vitro and is required for optimal photomixotrophic growth under aerobic and highly reducing conditions while the PDH complex is inactivated. We found that cells rely on a general shift from utilizing NAD(H)- to ferredoxin-dependent enzymes under these conditions. The utilization of ferredoxins instead of NAD(H) saves a greater share of the Gibbs-free energy, instead of wasting it as heat. This obviously simultaneously decelerates metabolic reactions as they operate closer to their thermodynamic equilibrium. It is common thought that during evolution, ferredoxins were replaced by NAD(P)H due to their higher stability in an oxidizing atmosphere. However, the utilization of NAD(P)H could also have been favored due to a higher competitiveness because of an accelerated metabolism.
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Affiliation(s)
- Yingying Wang
- Department of Biology, Christian-Albrechts University, Kiel, Germany
| | - Xi Chen
- Department of Biology, Christian-Albrechts University, Kiel, Germany
| | | | | | - Marko Boehm
- Department of Molecular Plant Physiology, University of Kassel, Kassel, Germany
| | - Jens Appel
- Department of Molecular Plant Physiology, University of Kassel, Kassel, Germany
| | - Thomas Barske
- Plant Physiology Department, University of Rostock, Rostock, Germany
| | - Stefan Timm
- Plant Physiology Department, University of Rostock, Rostock, Germany
| | | | - Martin Hagemann
- Plant Physiology Department, University of Rostock, Rostock, Germany
| | - Kirstin Gutekunst
- Department of Molecular Plant Physiology, University of Kassel, Kassel, Germany
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18
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Klähn S, Mikkat S, Riediger M, Georg J, Hess WR, Hagemann M. Integrative analysis of the salt stress response in cyanobacteria. Biol Direct 2021; 16:26. [PMID: 34906211 PMCID: PMC8670252 DOI: 10.1186/s13062-021-00316-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 11/29/2021] [Indexed: 12/24/2022] Open
Abstract
Microorganisms evolved specific acclimation strategies to thrive in environments of high or fluctuating salinities. Here, salt acclimation in the model cyanobacterium Synechocystis sp. PCC 6803 was analyzed by integrating transcriptomic, proteomic and metabolomic data. A dynamic reorganization of the transcriptome occurred during the first hours after salt shock, e.g. involving the upregulation of genes to activate compatible solute biochemistry balancing osmotic pressure. The massive accumulation of glucosylglycerol then had a measurable impact on the overall carbon and nitrogen metabolism. In addition, we observed the coordinated induction of putative regulatory RNAs and of several proteins known for their involvement in other stress responses. Overall, salt-induced changes in the proteome and transcriptome showed good correlations, especially among the stably up-regulated proteins and their transcripts. We define an extended salt stimulon comprising proteins directly or indirectly related to compatible solute metabolism, ion and water movements, and a distinct set of regulatory RNAs involved in post-transcriptional regulation. Our comprehensive data set provides the basis for engineering cyanobacterial salt tolerance and to further understand its regulation.
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Affiliation(s)
- Stephan Klähn
- Department of Solar Materials, Helmholtz-Centre for Environmental Research - UFZ, Leipzig, Germany.,Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Stefan Mikkat
- Core Facility Proteome Analysis, Rostock University Medical Center, Rostock, Germany
| | - Matthias Riediger
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Jens Georg
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Wolfgang R Hess
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Martin Hagemann
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, A.-Einstein-Str. 3, 18059, Rostock, Germany. .,Department Life, Light and Matter, University of Rostock, Rostock, Germany.
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19
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Selim KA, Haffner M, Burkhardt M, Mantovani O, Neumann N, Albrecht R, Seifert R, Krüger L, Stülke J, Hartmann MD, Hagemann M, Forchhammer K. Diurnal metabolic control in cyanobacteria requires perception of second messenger signaling molecule c-di-AMP by the carbon control protein SbtB. Sci Adv 2021; 7:eabk0568. [PMID: 34878830 PMCID: PMC8654305 DOI: 10.1126/sciadv.abk0568] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Because of their photosynthesis-dependent lifestyle, cyanobacteria evolved sophisticated regulatory mechanisms to adapt to oscillating day-night metabolic changes. How they coordinate the metabolic switch between autotrophic and glycogen-catabolic metabolism in light and darkness is poorly understood. Recently, c-di-AMP has been implicated in diurnal regulation, but its mode of action remains elusive. To unravel the signaling functions of c-di-AMP in cyanobacteria, we isolated c-di-AMP receptor proteins. Thereby, the carbon-sensor protein SbtB was identified as a major c-di-AMP receptor, which we confirmed biochemically and by x-ray crystallography. In search for the c-di-AMP signaling function of SbtB, we found that both SbtB and c-di-AMP cyclase–deficient mutants showed reduced diurnal growth and that c-di-AMP–bound SbtB interacts specifically with the glycogen-branching enzyme GlgB. Accordingly, both mutants displayed impaired glycogen synthesis during the day and impaired nighttime survival. Thus, the pivotal role of c-di-AMP in day-night acclimation can be attributed to SbtB-mediated regulation of glycogen metabolism.
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Affiliation(s)
- Khaled A. Selim
- Organismic Interactions Department, Interfaculty Institute for Microbiology and Infection Medicine, Cluster of Excellence ‘Controlling Microbes to Fight Infections’, Tübingen University, Auf der Morgenstelle 28, 72076 Tübingen, Germany
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
- Corresponding author. (K.A.S.); (K.F.)
| | - Michael Haffner
- Organismic Interactions Department, Interfaculty Institute for Microbiology and Infection Medicine, Cluster of Excellence ‘Controlling Microbes to Fight Infections’, Tübingen University, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Markus Burkhardt
- Organismic Interactions Department, Interfaculty Institute for Microbiology and Infection Medicine, Cluster of Excellence ‘Controlling Microbes to Fight Infections’, Tübingen University, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Oliver Mantovani
- Plant Physiology Department, Institute of Biological Sciences, Rostock University, Rostock, Germany
| | - Niels Neumann
- Organismic Interactions Department, Interfaculty Institute for Microbiology and Infection Medicine, Cluster of Excellence ‘Controlling Microbes to Fight Infections’, Tübingen University, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Reinhard Albrecht
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Roland Seifert
- Institute of Pharmacology, Hannover Medical School, Hannover, Germany
| | - Larissa Krüger
- Department of General Microbiology, Göttingen Center for Molecular Biosciences (GZMB), Göttingen University, Göttingen, Germany
| | - Jörg Stülke
- Department of General Microbiology, Göttingen Center for Molecular Biosciences (GZMB), Göttingen University, Göttingen, Germany
| | - Marcus D. Hartmann
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Martin Hagemann
- Plant Physiology Department, Institute of Biological Sciences, Rostock University, Rostock, Germany
| | - Karl Forchhammer
- Organismic Interactions Department, Interfaculty Institute for Microbiology and Infection Medicine, Cluster of Excellence ‘Controlling Microbes to Fight Infections’, Tübingen University, Auf der Morgenstelle 28, 72076 Tübingen, Germany
- Corresponding author. (K.A.S.); (K.F.)
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Lucius S, Makowka A, Michl K, Gutekunst K, Hagemann M. The Entner-Doudoroff Pathway Contributes to Glycogen Breakdown During High to Low CO 2 Shifts in the Cyanobacterium Synechocystis sp. PCC 6803. Front Plant Sci 2021; 12:787943. [PMID: 34956285 PMCID: PMC8698341 DOI: 10.3389/fpls.2021.787943] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/12/2021] [Indexed: 06/12/2023]
Abstract
Cyanobacteria perform plant-like oxygenic photosynthesis to convert inorganic carbon into organic compounds and can also use internal carbohydrate reserves under specific conditions. A mutant collection with defects in different routes for sugar catabolism was studied to analyze which of them is preferentially used to degrade glycogen reserves in light-exposed cells of Synechocystis sp. PCC 6803 shifted from high to low CO2 conditions. Mutants defective in the glycolytic Embden-Meyerhof-Parnas pathway or in the oxidative pentose-phosphate (OPP) pathway showed glycogen levels similar to wild type under high CO2 (HC) conditions and were able to degrade it similarly after shifts to low CO2 (LC) conditions. In contrast, the mutant Δeda, which is defective in the glycolytic Entner-Doudoroff (ED) pathway, accumulated elevated glycogen levels under HC that were more slowly consumed during the LC shift. In consequence, the mutant Δeda showed a lowered ability to respond to the inorganic carbon shifts, displayed a pronounced lack in the reactivation of growth when brought back to HC, and differed significantly in its metabolite composition. Particularly, Δeda accumulated enhanced levels of proline, which is a well-known metabolite to maintain redox balances via NADPH levels in many organisms under stress conditions. We suggest that deletion of eda might promote the utilization of the OPP shunt that dramatically enhance NADPH levels. Collectively, the results point at a major regulatory contribution of the ED pathway for the mobilization of glycogen reserves during rapid acclimation to fluctuating CO2 conditions.
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Affiliation(s)
- Stefan Lucius
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, Germany
| | - Alexander Makowka
- Department of Biology, Botanical Institute, Christian-Albrechts-University, Kiel, Germany
| | - Klaudia Michl
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, Germany
| | - Kirstin Gutekunst
- Department of Biology, Botanical Institute, Christian-Albrechts-University, Kiel, Germany
- Department of Molecular Plant Physiology, Bioenergetics in Photoautotrophs, University of Kassel, Kassel, Germany
| | - Martin Hagemann
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, Germany
- Interdisciplinary Faculty, Department Life, Light and Matter, University of Rostock, Rostock, Germany
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21
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Song K, Baumgartner D, Hagemann M, Muro-Pastor AM, Maaß S, Becher D, Hess WR. AtpΘ is an inhibitor of F 0F 1 ATP synthase to arrest ATP hydrolysis during low-energy conditions in cyanobacteria. Curr Biol 2021; 32:136-148.e5. [PMID: 34762820 DOI: 10.1016/j.cub.2021.10.051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/14/2021] [Accepted: 10/22/2021] [Indexed: 10/19/2022]
Abstract
Biological processes in all living cells are powered by ATP, a nearly universal molecule of energy transfer. ATP synthases produce ATP utilizing proton gradients that are usually generated by either respiration or photosynthesis. However, cyanobacteria are unique in combining photosynthetic and respiratory electron transport chains in the same membrane system, the thylakoids. How cyanobacteria prevent the futile reverse operation of ATP synthase under unfavorable conditions pumping protons while hydrolyzing ATP is mostly unclear. Here, we provide evidence that the small protein AtpΘ, which is widely conserved in cyanobacteria, is mainly fulfilling this task. The expression of AtpΘ becomes induced under conditions such as darkness or heat shock, which can lead to a weakening of the proton gradient. Translational fusions of AtpΘ to the green fluorescent protein revealed targeting to the thylakoid membrane. Immunoprecipitation assays followed by mass spectrometry and far western blots identified subunits of ATP synthase as interacting partners of AtpΘ. ATP hydrolysis assays with isolated membrane fractions, as well as purified ATP synthase complexes, demonstrated that AtpΘ inhibits ATPase activity in a dose-dependent manner similar to the F0F1-ATP synthase inhibitor N,N-dicyclohexylcarbodimide. The results show that, even in a well-investigated process, crucial new players can be discovered if small proteins are taken into consideration and indicate that ATP synthase activity can be controlled in surprisingly different ways.
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Affiliation(s)
- Kuo Song
- University of Freiburg, Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, 79104 Freiburg, Germany
| | - Desirée Baumgartner
- University of Freiburg, Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, 79104 Freiburg, Germany
| | - Martin Hagemann
- University of Rostock, Institute of Biosciences, Plant Physiology Department, Albert-Einstein-Str. 3, 18059 Rostock, Germany
| | - Alicia M Muro-Pastor
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, 41092 Sevilla, Spain
| | - Sandra Maaß
- University of Greifswald, Department of Microbial Proteomics, Institute of Microbiology, 17489 Greifswald, Germany
| | - Dörte Becher
- University of Greifswald, Department of Microbial Proteomics, Institute of Microbiology, 17489 Greifswald, Germany
| | - Wolfgang R Hess
- University of Freiburg, Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, 79104 Freiburg, Germany.
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22
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Oren N, Timm S, Frank M, Mantovani O, Murik O, Hagemann M. Red/far-red light signals regulate the activity of the carbon-concentrating mechanism in cyanobacteria. Sci Adv 2021; 7:7/34/eabg0435. [PMID: 34407941 PMCID: PMC8373116 DOI: 10.1126/sciadv.abg0435] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 06/28/2021] [Indexed: 05/11/2023]
Abstract
Desiccation-tolerant cyanobacteria can survive frequent hydration/dehydration cycles likely affecting inorganic carbon (Ci) levels. It was recently shown that red/far-red light serves as signal-preparing cells toward dehydration. Here, the effects of desiccation on Ci assimilation by Leptolyngbya ohadii isolated from Israel's Negev desert were investigated. Metabolomic investigations indicated a decline in ribulose-1,5-bisphosphate carboxylase/oxygenase carboxylation activity, and this was accelerated by far-red light. Far-red light negatively affected the Ci affinity of L. ohadii during desiccation and in liquid cultures. Similar effects were evident in the non-desiccation-tolerant cyanobacterium Synechocystis The Synechocystis Δcph1 mutant lacking the major phytochrome exhibited reduced photosynthetic Ci affinity when exposed to far-red light, whereas the mutant ΔsbtB lacking a Ci uptake inhibitory protein lost the far-red light inhibition. Collectively, these results suggest that red/far-red light perception likely via phytochromes regulates Ci uptake by cyanobacteria and that this mechanism contributes to desiccation tolerance in strains such as L. ohadii.
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Affiliation(s)
- Nadav Oren
- Plant Physiology Department, University of Rostock, Albert-Einstein-Str. 3, D-18059 Rostock, Germany.
| | - Stefan Timm
- Plant Physiology Department, University of Rostock, Albert-Einstein-Str. 3, D-18059 Rostock, Germany
| | - Marcus Frank
- Medical Biology and Electron Microscopy Centre, Medical Faculty, University of Rostock, Strempelstr. 14, 18057 Rostock, Germany
- Department of Life, Light, and Matter, University of Rostock, Albert-Einstein-Str. 25, 18059 Rostock, Germany
| | - Oliver Mantovani
- Plant Physiology Department, University of Rostock, Albert-Einstein-Str. 3, D-18059 Rostock, Germany
| | - Omer Murik
- Medical Genetics Institute, Shaare Zedek Medical Center, 9103102 Jerusalem, Israel
| | - Martin Hagemann
- Plant Physiology Department, University of Rostock, Albert-Einstein-Str. 3, D-18059 Rostock, Germany
- Department of Life, Light, and Matter, University of Rostock, Albert-Einstein-Str. 25, 18059 Rostock, Germany
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23
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Spät P, Barske T, Maček B, Hagemann M. Alterations in the CO 2 availability induce alterations in the phosphoproteome of the cyanobacterium Synechocystis sp. PCC 6803. New Phytol 2021; 231:1123-1137. [PMID: 34058021 DOI: 10.1111/nph.17423] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 04/16/2021] [Indexed: 06/12/2023]
Abstract
Cyanobacteria are the only prokaryotes that perform plant-like oxygenic photosynthesis. They evolved an inorganic carbon-concentrating mechanism to adapt to low CO2 conditions. Quantitative phosphoproteomics was applied to analyze regulatory features during the acclimation to low CO2 conditions in the model cyanobacterium Synechocystis sp. PCC 6803. Overall, more than 2500 proteins were quantified, equivalent to c. 70% of the Synechocystis theoretical proteome. Proteins with changing abundances correlated largely with mRNA expression levels. Functional annotation of the noncorrelating proteins revealed an enrichment of key metabolic processes fundamental for maintaining cellular homeostasis. Furthermore, 105 phosphoproteins harboring over 200 site-specific phosphorylation events were identified. Subunits of the bicarbonate transporter BCT1 and the redox switch protein CP12 were among phosphoproteins with reduced phosphorylation levels at lower CO2 , whereas the serine/threonine protein kinase SpkC revealed increased phosphorylation levels. The corresponding ΔspkC mutant was characterized and showed decreased ability to acclimate to low CO2 conditions. Possible phosphorylation targets of SpkC including a BCT1 subunit were identified by phosphoproteomics. Collectively, our study highlights the importance of posttranscriptional regulation of protein abundances as well as posttranslational regulation by protein phosphorylation for the successful acclimation towards low CO2 conditions in Synechocystis and possibly among cyanobacteria.
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Affiliation(s)
- Philipp Spät
- Department of Organismic Interactions, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, D-72076, Germany
- Department of Quantitative Proteomics, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, D-72076, Germany
| | - Thomas Barske
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, D-18059, Germany
| | - Boris Maček
- Department of Quantitative Proteomics, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, D-72076, Germany
| | - Martin Hagemann
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, D-18059, Germany
- Department Life, Light and Matter, Interdisciplinary Faculty, University of Rostock, Rostock, D-18059, Germany
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Bolay P, Rozbeh R, Muro-Pastor MI, Timm S, Hagemann M, Florencio FJ, Forchhammer K, Klähn S. The Novel P II-Interacting Protein PirA Controls Flux into the Cyanobacterial Ornithine-Ammonia Cycle. mBio 2021; 12:e00229-21. [PMID: 33758091 PMCID: PMC8092223 DOI: 10.1128/mbio.00229-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 02/16/2021] [Indexed: 12/11/2022] Open
Abstract
Among prokaryotes, cyanobacteria have an exclusive position as they perform oxygenic photosynthesis. Cyanobacteria substantially differ from other bacteria in further aspects, e.g., they evolved a plethora of unique regulatory mechanisms to control primary metabolism. This is exemplified by the regulation of glutamine synthetase (GS) via small proteins termed inactivating factors (IFs). Here, we reveal another small protein, encoded by the ssr0692 gene in the model strain Synechocystis sp. PCC 6803, that regulates flux into the ornithine-ammonia cycle (OAC), the key hub of cyanobacterial nitrogen stockpiling and remobilization. This regulation is achieved by the interaction with the central carbon/nitrogen control protein PII, which commonly controls entry into the OAC by activating the key enzyme of arginine synthesis, N-acetyl-l-glutamate kinase (NAGK). In particular, the Ssr0692 protein competes with NAGK for PII binding and thereby prevents NAGK activation, which in turn lowers arginine synthesis. Accordingly, we termed it PII-interacting regulator of arginine synthesis (PirA). Similar to the GS IFs, PirA accumulates in response to ammonium upshift due to relief from repression by the global nitrogen control transcription factor NtcA. Consistent with this, the deletion of pirA affects the balance of metabolite pools of the OAC in response to ammonium shocks. Moreover, the PirA-PII interaction requires ADP and is prevented by PII mutations affecting the T-loop conformation, the major protein interaction surface of this signal processing protein. Thus, we propose that PirA is an integrator determining flux into N storage compounds not only depending on the N availability but also the energy state of the cell.IMPORTANCE Cyanobacteria contribute a significant portion to the annual oxygen yield and play important roles in biogeochemical cycles, e.g., as major primary producers. Due to their photosynthetic lifestyle, cyanobacteria also arouse interest as hosts for the sustainable production of fuel components and high-value chemicals. However, their broad application as microbial cell factories is hampered by limited knowledge about the regulation of metabolic fluxes in these organisms. Our research identified a novel regulatory protein that controls nitrogen flux, in particular arginine synthesis. Besides its role as a proteinogenic amino acid, arginine is a precursor for the cyanobacterial storage compound cyanophycin, which is of potential interest to biotechnology. Therefore, the obtained results will not only enhance our understanding of flux control in these organisms but also help to provide a scientific basis for targeted metabolic engineering and, hence, the design of photosynthesis-driven biotechnological applications.
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Affiliation(s)
- Paul Bolay
- Helmholtz Centre for Environmental Research, Department of Solar Materials, Leipzig, Germany
| | - Rokhsareh Rozbeh
- Interfaculty Institute for Microbiology and Infection Medicine, Organismic Interactions Department, Tübingen University, Tübingen, Germany
| | - M Isabel Muro-Pastor
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Sevilla, Spain
| | - Stefan Timm
- Department of Plant Physiology, University of Rostock, Rostock, Germany
| | - Martin Hagemann
- Department of Plant Physiology, University of Rostock, Rostock, Germany
| | - Francisco J Florencio
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Sevilla, Spain
| | - Karl Forchhammer
- Interfaculty Institute for Microbiology and Infection Medicine, Organismic Interactions Department, Tübingen University, Tübingen, Germany
| | - Stephan Klähn
- Helmholtz Centre for Environmental Research, Department of Solar Materials, Leipzig, Germany
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Scheurer NM, Rajarathinam Y, Timm S, Köbler C, Kopka J, Hagemann M, Wilde A. Homologs of Circadian Clock Proteins Impact the Metabolic Switch Between Light and Dark Growth in the Cyanobacterium Synechocystis sp. PCC 6803. Front Plant Sci 2021; 12:675227. [PMID: 34239525 PMCID: PMC8258377 DOI: 10.3389/fpls.2021.675227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 05/26/2021] [Indexed: 05/06/2023]
Abstract
The putative circadian clock system of the facultative heterotrophic cyanobacterial strain Synechocystis sp. PCC 6803 comprises the following three Kai-based systems: a KaiABC-based potential oscillator that is linked to the SasA-RpaA two-component output pathway and two additional KaiBC systems without a cognate KaiA component. Mutants lacking the genes encoding the KaiAB1C1 components or the response regulator RpaA show reduced growth in light/dark cycles and do not show heterotrophic growth in the dark. In the present study, the effect of these mutations on central metabolism was analyzed by targeted and non-targeted metabolite profiling. The strongest metabolic changes were observed in the dark in ΔrpaA and, to a lesser extent, in the ΔkaiAB1C1 mutant. These observations included the overaccumulation of 2-phosphoglycolate, which correlated with the overaccumulation of the RbcL subunit in the mutants, and taken together, these data suggest enhanced RubisCO activity in the dark. The imbalanced carbon metabolism in the ΔrpaA mutant extended to the pyruvate family of amino acids, which showed increased accumulation in the dark. Hence, the deletion of the response regulator rpaA had a more pronounced effect on metabolism than the deletion of the kai genes. The larger impact of the rpaA mutation is in agreement with previous transcriptomic analyses and likely relates to a KaiAB1C1-independent function as a transcription factor. Collectively, our data demonstrate an important role of homologs of clock proteins in Synechocystis for balanced carbon and nitrogen metabolism during light-to-dark transitions.
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Affiliation(s)
- Nina M. Scheurer
- Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Yogeswari Rajarathinam
- Applied Metabolome Analysis, Department of Molecular Physiology, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Stefan Timm
- Department of Plant Physiology, University of Rostock, Rostock, Germany
| | - Christin Köbler
- Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Joachim Kopka
- Applied Metabolome Analysis, Department of Molecular Physiology, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Martin Hagemann
- Department of Plant Physiology, University of Rostock, Rostock, Germany
| | - Annegret Wilde
- Institute of Biology III, University of Freiburg, Freiburg, Germany
- *Correspondence: Annegret Wilde
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26
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Song S, Timm S, Lindner SN, Reimann V, Hess WR, Hagemann M, Brouwer EM. Expression of Formate-Tetrahydrofolate Ligase Did Not Improve Growth but Interferes With Nitrogen and Carbon Metabolism of Synechocystis sp. PCC 6803. Front Microbiol 2020; 11:1650. [PMID: 32760387 PMCID: PMC7372957 DOI: 10.3389/fmicb.2020.01650] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 06/25/2020] [Indexed: 12/16/2022] Open
Abstract
The introduction of alternative CO2-fixing pathways in photoautotrophic organism may improve the efficiency of biological carbon fixation such as minimizing the carbon loss due to photorespiration. Here, we analyzed the effects of creating a formate entry point into the primary metabolism of the cyanobacterium Synechocystis sp. PCC 6803. The formate-tetrahydrofolate ligase (FTL) from Methylobacterium extorquens AM1 was expressed in Synechocystis to enable formate assimilation and reducing the loss of fixed carbon in the photorespiratory pathway. Transgenic strains accumulated serine and 3-phosphoglycerate, and consumed more 2-phosphoglycolate and glycine, which seemed to reflect an efficient utilization of formate. However, labeling experiments showed that the serine accumulation was not due to the expected incorporation of formate. Subsequent DNA-microarray analysis revealed profound changes in transcript abundance due to ftl expression. Transcriptome changes were observed in relation to serine and glycine metabolism, C1-metabolism and particularly nitrogen assimilation. The data implied that ftl expression interfered with the signaling the carbon/nitrogen ratio in Synechocystis. Our results indicate that the expression of new enzymes could have a severe impact on the cellular regulatory network, which potentially hinders the establishment of newly designed pathways.
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Affiliation(s)
- Shanshan Song
- Plant Physiology Department, Institute of Biosciences, University of Rostock, Rostock, Germany
| | - Stefan Timm
- Plant Physiology Department, Institute of Biosciences, University of Rostock, Rostock, Germany
| | - Steffen N. Lindner
- Max Planck Institute of Molekular Plant Physiology, Potsdam-Golm, Germany
| | - Viktoria Reimann
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg im Breisgau, Germany
| | - Wolfgang R. Hess
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg im Breisgau, Germany
| | - Martin Hagemann
- Plant Physiology Department, Institute of Biosciences, University of Rostock, Rostock, Germany
| | - Eva-Maria Brouwer
- Plant Physiology Department, Institute of Biosciences, University of Rostock, Rostock, Germany
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Timm S, Hagemann M. Photorespiration-how is it regulated and how does it regulate overall plant metabolism? J Exp Bot 2020; 71:3955-3965. [PMID: 32274517 DOI: 10.1093/jxb/eraa183] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 04/08/2020] [Indexed: 05/03/2023]
Abstract
Under the current atmospheric conditions, oxygenic photosynthesis requires photorespiration to operate. In the presence of low CO2/O2 ratios, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) performs an oxygenase side reaction, leading to the formation of high amounts of 2-phosphoglycolate during illumination. Given that 2-phosphoglycolate is a potent inhibitor of photosynthetic carbon fixation, it must be immediately removed through photorespiration. The core photorespiratory cycle is orchestrated across three interacting subcellular compartments, namely chloroplasts, peroxisomes, and mitochondria, and thus cross-talks with a multitude of other cellular processes. Over the past years, the metabolic interaction of photorespiration and photosynthetic CO2 fixation has attracted major interest because research has demonstrated the enhancement of C3 photosynthesis and growth through the genetic manipulation of photorespiration. However, to optimize future engineering approaches, it is also essential to improve our current understanding of the regulatory mechanisms of photorespiration. Here, we summarize recent progress regarding the steps that control carbon flux in photorespiration, eventually involving regulatory proteins and metabolites. In this regard, both genetic engineering and the identification of various layers of regulation point to glycine decarboxylase as the key enzyme to regulate and adjust the photorespiratory carbon flow. Potential implications of the regulation of photorespiration for acclimation to environmental changes along with open questions are also discussed.
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Affiliation(s)
- Stefan Timm
- University of Rostock, Plant Physiology Department, Rostock, Germany
| | - Martin Hagemann
- University of Rostock, Plant Physiology Department, Rostock, Germany
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28
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Wittmiß M, Mikkat S, Hagemann M, Bauwe H. Stoichiometry of two plant glycine decarboxylase complexes and comparison with a cyanobacterial glycine cleavage system. Plant J 2020; 103:801-813. [PMID: 32311173 DOI: 10.1111/tpj.14773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 04/01/2020] [Accepted: 04/07/2020] [Indexed: 06/11/2023]
Abstract
The multienzyme glycine cleavage system (GCS) converts glycine and tetrahydrofolate to the one-carbon compound 5,10-methylenetetrahydrofolate, which is of vital importance for most if not all organisms. Photorespiring plant mitochondria contain very high levels of GCS proteins organised as a fragile glycine decarboxylase complex (GDC). The aim of this study is to provide mass spectrometry-based stoichiometric data for the plant leaf GDC and examine whether complex formation could be a general property of the GCS in photosynthesizing organisms. The molar ratios of the leaf GDC component proteins are 1L2 -4P2 -8T-26H and 1L2 -4P2 -8T-20H for pea and Arabidopsis, respectively, as determined by mass spectrometry. The minimum mass of the plant leaf GDC ranges from 1550 to 1650 kDa, which is larger than previously assumed. The Arabidopsis GDC contains four times more of the isoforms GCS-P1 and GCS-L1 in comparison with GCS-P2 and GCS-L2, respectively, whereas the H-isoproteins GCS-H1 and GCS-H3 are fully redundant as indicated by their about equal amounts. Isoform GCS-H2 is not present in leaf mitochondria. In the cyanobacterium Synechocystis sp. PCC 6803, GCS proteins concentrations are low but above the complex formation threshold reported for pea leaf GDC. Indeed, formation of a cyanobacterial GDC from the individual recombinant GCS proteins in vitro could be demonstrated. Presence and metabolic significance of a Synechocystis GDC in vivo remain to be examined but could involve multimers of the GCS H-protein that dynamically crosslink the three GCS enzyme proteins, facilitating glycine metabolism by the formation of multienzyme metabolic complexes. Data are available via ProteomeXchange with identifier PXD018211.
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Affiliation(s)
- Maria Wittmiß
- Department of Plant Physiology, University of Rostock, Albert-Einstein-Straße 3, D-18059, Rostock, Germany
| | - Stefan Mikkat
- Core Facility Proteome Analysis, Rostock University Medical Center, Schilling-Allee 69, D-18057, Rostock, Germany
| | - Martin Hagemann
- Department of Plant Physiology, University of Rostock, Albert-Einstein-Straße 3, D-18059, Rostock, Germany
| | - Hermann Bauwe
- Department of Plant Physiology, University of Rostock, Albert-Einstein-Straße 3, D-18059, Rostock, Germany
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29
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de Alvarenga LV, Hess WR, Hagemann M. AcnSP - A Novel Small Protein Regulator of Aconitase Activity in the Cyanobacterium Synechocystis sp. PCC 6803. Front Microbiol 2020; 11:1445. [PMID: 32695088 PMCID: PMC7336809 DOI: 10.3389/fmicb.2020.01445] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 06/04/2020] [Indexed: 12/28/2022] Open
Abstract
Synechocystis sp. PCC 6803 is a widely used model cyanobacterium whose genome has been well annotated. However, several additional small protein coding sequences (sORFs) have been recently identified, which might play important roles, for example in the regulation of cellular metabolism. Here, we analyzed the function of a sORF encoding a 44 amino acid peptide showing high similarity to the N-terminal part of aconitase (AcnB). The expression of the gene, which probably originated from a partial gene duplication of chromosomal acnB into the plasmid pSYSA, was verified and it was designated as acnSP. The protein-coding part of acnSP was inactivated by interposon mutagenesis. The obtained mutant displayed slower growth under photoautotrophic conditions with light exceeding 100 μmol photons m–2 s–1 and showed significant changes in the metabolome compared to wild type, including alterations in many metabolites associated to the tricarboxylic acid (TCA) cycle. To analyze a possible direct impact of AcnSP on aconitase, the recombinant Synechocystis enzyme was generated and biochemically characterized. Biochemical analysis revealed that addition of equimolar amounts of AcnSP resulted in an improved substrate affinity (lower Km) and lowered Vmax of aconitase. These results imply that AcnSP can regulate aconitase activity, thereby impacting the carbon flow into the oxidative branch of the cyanobacterial TCA cycle, which is mainly responsible for the synthesis of carbon skeletons needed for ammonia assimilation.
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Affiliation(s)
- Luna V de Alvarenga
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, Germany
| | - Wolfgang R Hess
- Genetics & Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Freiburg im Breisgau, Germany
| | - Martin Hagemann
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, Germany.,Department Life, Light and Matter, University of Rostock, Rostock, Germany
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30
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Hagemann M, Kaplan A. Is the Structure of the CO 2-Hydrating Complex I Compatible with the Cyanobacterial CO 2-Concentrating Mechanism? Plant Physiol 2020; 183:460-463. [PMID: 32213538 PMCID: PMC7271811 DOI: 10.1104/pp.20.00220] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 03/20/2020] [Indexed: 05/28/2023]
Abstract
The structure of CO2 hydration complex I is not compatible with the view on how this complex is embedded and functions in the cyanobacterial carbon-concentrating mechanism.
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Affiliation(s)
- Martin Hagemann
- Department Plant Physiology, University of Rostock, D18059 Rostock, Germany
| | - Aaron Kaplan
- Plants and Environmental Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel
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Mahmoud A, Hagemann M. CONCURRENT INSERTION AND INTERNAL FIXATION OF SELF-EXPANDABLE METALLIC STENT (SEMS) IN PROXIMAL TRACHEAL STENOSIS IN HIGH-RISK PATIENTS. Chest 2020. [DOI: 10.1016/j.chest.2020.05.256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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de Alvarenga LV, Lucius S, Vaz MGMV, Araújo WL, Hagemann M. The novel strain Desmonostoc salinum CCM-UFV059 shows higher salt and desiccation resistance compared to the model strain Nostoc sp. PCC7120. J Phycol 2020; 56:496-506. [PMID: 31925964 DOI: 10.1111/jpy.12968] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 12/04/2019] [Indexed: 06/10/2023]
Abstract
Desmonostoc salinum CCM-UFV059 (Desmonostoc) is a novel cyanobacterial strain of the order Nostocales isolated from a saline-alkaline lake. The acclimation towards salt and desiccation stress of Desmonostoc was compared to the related and well-characterized model strain Nostoc sp. PCC7120 (Nostoc). Salt-stressed cells of Desmonostoc maintained low cellular Na+ concentrations and accumulated high amounts of compatible solutes, mainly sucrose and to a lower extent trehalose. These features permitted Desmonostoc to grow and maintain photosynthesis at 2-fold higher salinities than Nostoc. Moreover, Desmonostoc also induced sucrose over-accumulation under desiccation, which allowed this strain to recover from this stress in contrast to Nostoc. Additional mechanisms such as the presence of highly unsaturated lipids in the membrane and an efficient ion transport system could also explain, at least partially, how Desmonostoc is able to acclimate to high salinities and to resist longer desiccation periods. Collectively, our results provide first insights into the physiological and metabolic adaptations explaining the remarkable high salt and desiccation tolerance, which qualify Desmonostoc as an attractive model for further analysis of stress acclimation among heterocystous N2 -fixing cyanobacteria.
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Affiliation(s)
- Luna Viggiano de Alvarenga
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
- Max-Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
- Institut für Biowissenschaften, Abteilung Pflanzenphysiologie, Universität Rostock, A.-Einstein-Str. 3, Rostock, D-18059, Germany
| | - Stefan Lucius
- Institut für Biowissenschaften, Abteilung Pflanzenphysiologie, Universität Rostock, A.-Einstein-Str. 3, Rostock, D-18059, Germany
| | - Marcelo Gomes Marçal Vieira Vaz
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
- Max-Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
| | - Wagner L Araújo
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
- Max-Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil
| | - Martin Hagemann
- Institut für Biowissenschaften, Abteilung Pflanzenphysiologie, Universität Rostock, A.-Einstein-Str. 3, Rostock, D-18059, Germany
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Timm S, Woitschach F, Heise C, Hagemann M, Bauwe H. Faster Removal of 2-Phosphoglycolate through Photorespiration Improves Abiotic Stress Tolerance of Arabidopsis. Plants (Basel) 2019; 8:plants8120563. [PMID: 31810232 PMCID: PMC6963629 DOI: 10.3390/plants8120563] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 11/27/2019] [Accepted: 11/29/2019] [Indexed: 02/06/2023]
Abstract
Photorespiration metabolizes 2-phosphoglyolate (2-PG) to avoid inhibition of carbon assimilation and allocation. In addition to 2-PG removal, photorespiration has been shown to play a role in stress protection. Here, we studied the impact of faster 2-PG degradation through overexpression of 2-PG phosphatase (PGLP) on the abiotic stress-response of Arabidopsis thaliana (Arabidopsis). Two transgenic lines and the wild type were subjected to short-time high light and elevated temperature stress during gas exchange measurements. Furthermore, the same lines were exposed to long-term water shortage and elevated temperature stresses. Faster 2-PG degradation allowed maintenance of photosynthesis at combined light and temperatures stress and under water-limiting conditions. The PGLP-overexpressing lines also showed higher photosynthesis compared to the wild type if grown in high temperatures, which also led to increased starch accumulation and shifts in soluble sugar contents. However, only minor effects were detected on amino and organic acid levels. The wild type responded to elevated temperatures with elevated mRNA and protein levels of photorespiratory enzymes, while the transgenic lines displayed only minor changes. Collectively, these results strengthen our previous hypothesis that a faster photorespiratory metabolism improves tolerance against unfavorable environmental conditions, such as high light intensity and temperature as well as drought. In case of PGLP, the likely mechanism is alleviation of inhibitory feedback of 2-PG onto the Calvin–Benson cycle, facilitating carbon assimilation and accumulation of transitory starch.
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Affiliation(s)
- Stefan Timm
- Plant Physiology Department, University of Rostock, Albert-Einstein-Straße 3, D-18051 Rostock, Germany; (F.W.); (C.H.); (M.H.); (H.B.)
- Correspondence: ; Tel.: +49-(0)381-4986115; Fax: +49-(0)381-4986112
| | - Franziska Woitschach
- Plant Physiology Department, University of Rostock, Albert-Einstein-Straße 3, D-18051 Rostock, Germany; (F.W.); (C.H.); (M.H.); (H.B.)
- Division of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University Medical Center Rostock, Ernst-Heydemann-Str.6, D-18057 Rostock, Germany
| | - Carolin Heise
- Plant Physiology Department, University of Rostock, Albert-Einstein-Straße 3, D-18051 Rostock, Germany; (F.W.); (C.H.); (M.H.); (H.B.)
| | - Martin Hagemann
- Plant Physiology Department, University of Rostock, Albert-Einstein-Straße 3, D-18051 Rostock, Germany; (F.W.); (C.H.); (M.H.); (H.B.)
| | - Hermann Bauwe
- Plant Physiology Department, University of Rostock, Albert-Einstein-Straße 3, D-18051 Rostock, Germany; (F.W.); (C.H.); (M.H.); (H.B.)
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Barchewitz T, Guljamow A, Meissner S, Timm S, Henneberg M, Baumann O, Hagemann M, Dittmann E. Non-canonical localization of RubisCO under high-light conditions in the toxic cyanobacterium Microcystis aeruginosa PCC7806. Environ Microbiol 2019; 21:4836-4851. [PMID: 31637830 DOI: 10.1111/1462-2920.14837] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/11/2019] [Accepted: 10/18/2019] [Indexed: 01/25/2023]
Abstract
The frequent production of the hepatotoxin microcystin (MC) and its impact on the lifestyle of bloom-forming cyanobacteria are poorly understood. Here, we report that MC interferes with the assembly and the subcellular localization of RubisCO, in Microcystis aeruginosa PCC7806. Immunofluorescence, electron microscopic and cellular fractionation studies revealed a pronounced heterogeneity in the subcellular localization of RubisCO. At high cell density, RubisCO particles are largely separate from carboxysomes in M. aeruginosa and relocate to the cytoplasmic membrane under high-light conditions. We hypothesize that the binding of MC to RubisCO promotes its membrane association and enables an extreme versatility of the enzyme. Steady-state levels of the RubisCO CO2 fixation product 3-phosphoglycerate are significantly higher in the MC-producing wild type. We also detected noticeable amounts of the RubisCO oxygenase reaction product secreted into the medium that may support the mutual interaction of M. aeruginosa with its heterotrophic microbial community.
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Affiliation(s)
- Tino Barchewitz
- Department of Microbiology, Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam-Golm, Germany
| | - Arthur Guljamow
- Department of Microbiology, Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam-Golm, Germany
| | - Sven Meissner
- Department of Microbiology, Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam-Golm, Germany
| | - Stefan Timm
- Department of Plant Physiology, Institute Biological Sciences, University of Rostock, Albert-Einstein-Str. 3, 18059 Rostock, Germany
| | - Manja Henneberg
- Department of Plant Physiology, Institute Biological Sciences, University of Rostock, Albert-Einstein-Str. 3, 18059 Rostock, Germany
| | - Otto Baumann
- Department of Zoophysiology, Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam-Golm, Germany
| | - Martin Hagemann
- Department of Plant Physiology, Institute Biological Sciences, University of Rostock, Albert-Einstein-Str. 3, 18059 Rostock, Germany
| | - Elke Dittmann
- Department of Microbiology, Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam-Golm, Germany
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Reinholdt O, Schwab S, Zhang Y, Reichheld JP, Fernie AR, Hagemann M, Timm S. Redox-Regulation of Photorespiration through Mitochondrial Thioredoxin o1. Plant Physiol 2019; 181:442-457. [PMID: 31413204 PMCID: PMC6776843 DOI: 10.1104/pp.19.00559] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 07/30/2019] [Indexed: 05/02/2023]
Abstract
Photorespiration sustains photosynthesis in the presence of oxygen due to rapid metabolization of 2-phosphoglycolate, the major side-product of the oxygenase activity of Rubisco that also directly impedes carbon assimilation and allocation. Despite the fact that both the biochemical reactions and the underlying genetics are well characterized, information concerning the regulatory mechanisms that adjust photorespiratory flux is rare. Here, we studied the impact of mitochondrial-localized thioredoxin o1 (TRXo1) on photorespiratory metabolism. The characterization of an Arabidopsis (Arabidopsis thaliana) transfer DNA insertional line (trxo1-1) revealed an increase in the stoichiometry of photorespiratory CO2 release and impaired Gly-to-Ser turnover after a shift from high-to-low CO2 without changes in Gly decarboxylase (GDC) gene or protein expression. These effects were distinctly pronounced in a double mutant, where the TRXo1 mutation was combined with strongly reduced GDC T-protein expression. The double mutant (TxGT) showed reduced growth in air but not in high CO2, decreased photosynthesis, and up to 54-fold more Gly alongside several redox-stress-related metabolites. Given that GDC proteins are potential targets for redox-regulation, we also examined the in vitro properties of recombinant GDC l-proteins (lipoamide dehydrogenase) from plants and the cyanobacterium Synechocystis species strain PCC6803 and observed a redox-dependent inhibition by either artificial reducing agents or TRXo1 itself. Collectively, our results demonstrate that TRXo1 potentially adjusts photorespiration via redox-regulation of GDC in response to environmental changes.
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Affiliation(s)
- Ole Reinholdt
- University of Rostock, Plant Physiology Department, Albert-Einstein-Straße 3, D-18059 Rostock, Germany
| | - Saskia Schwab
- University of Rostock, Plant Physiology Department, Albert-Einstein-Straße 3, D-18059 Rostock, Germany
| | - Youjun Zhang
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Golm, Germany
- Center of Plant System Biology and Biotechnology, 4000 Plovdiv, Bulgaria
| | - Jean-Philippe Reichheld
- Laboratoire Génome et Développement des Plantes, CNRS, F-66860 Perpignan, France
- Laboratoire Génome et Développement des Plantes, Université Perpignan Via Domitia, F-66860 Perpignan, France
| | - Alisdair R Fernie
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Golm, Germany
- Center of Plant System Biology and Biotechnology, 4000 Plovdiv, Bulgaria
| | - Martin Hagemann
- University of Rostock, Plant Physiology Department, Albert-Einstein-Straße 3, D-18059 Rostock, Germany
| | - Stefan Timm
- University of Rostock, Plant Physiology Department, Albert-Einstein-Straße 3, D-18059 Rostock, Germany
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Kirsch F, Klähn S, Hagemann M. Salt-Regulated Accumulation of the Compatible Solutes Sucrose and Glucosylglycerol in Cyanobacteria and Its Biotechnological Potential. Front Microbiol 2019; 10:2139. [PMID: 31572343 PMCID: PMC6753628 DOI: 10.3389/fmicb.2019.02139] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 08/30/2019] [Indexed: 12/11/2022] Open
Abstract
Cyanobacteria are prokaryotes that can assimilate inorganic carbon via oxygenic photosynthesis, which results in the formation of organic compounds essentially from CO2, water, and light. Increasing concerns regarding the increase in atmospheric CO2 due to fossil energy usage fueled the idea of a photosynthesis-driven and CO2-neutral, i.e., cyanobacteria-based biotechnology. The ability of various cyanobacteria to tolerate high and/or fluctuating salinities attenuates the requirement of freshwater for their cultivation, which makes these organisms even more interesting regarding a sustainable utilization of natural resources. However, those applications require a detailed knowledge of the processes involved in salt acclimation. Here, we review the current state of our knowledge on the regulation of compatible solute accumulation in cyanobacteria. The model organism Synechocystis sp. PCC 6803 responds to increasing salinities mainly by the accumulation of glucosylglycerol (GG) and sucrose. After exposure toward increased salt concentrations, the accumulation of the main compatible solute GG is achieved by de novo synthesis. The key target of regulation is the enzyme GG-phosphate synthase (GgpS) and involves transcriptional, posttranscriptional, and biochemical mechanisms. Recently, the GG-degrading enzyme GG hydrolase A (GghA) was identified, which is particularly important for GG degradation during exposure to decreasing salinities. The inversely ion-regulated activities of GgpS and GghA could represent the main model for effectively tuning GG steady state levels according to external salinities. Similar to GG, the intracellular amount of sucrose is also salt-regulated and seems to be determined by the balance of sucrose synthesis via sucrose-phosphate synthase (Sps) and its degradation via invertase (Inv). In addition to their role as stress protectants, both compatible solutes also represent promising targets for biotechnology. Hence, the increasing knowledge on the regulation of compatible solute accumulation not only improves our understanding of the stress physiology of cyanobacteria but will also support their future biotechnological applications.
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Affiliation(s)
- Friedrich Kirsch
- Department of Plant Physiology, Institute for Biosciences, University of Rostock, Rostock, Germany
| | - Stephan Klähn
- Department of Solar Materials, Helmholtz-Centre for Environmental Research-UFZ, Leipzig, Germany
| | - Martin Hagemann
- Department of Plant Physiology, Institute for Biosciences, University of Rostock, Rostock, Germany
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Scholz I, Lott SC, Behler J, Gärtner K, Hagemann M, Hess WR. Divergent methylation of CRISPR repeats and cas genes in a subtype I-D CRISPR-Cas-system. BMC Microbiol 2019; 19:147. [PMID: 31262257 PMCID: PMC6604393 DOI: 10.1186/s12866-019-1526-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 06/20/2019] [Indexed: 02/07/2023] Open
Abstract
Background The presence and activity of CRISPR-Cas defense systems is a hallmark of many prokaryotic microorganisms. Here, the distribution of sequences related to the highly iterated palindrome 1 (HIP1) element and the DNA methylation of CGATCG motifs embedded within HIP1 as a vital part of the CRISPR1 repeat sequence was analyzed in the cyanobacterium Synechocystis sp. PCC 6803. Previously suggested functions of HIP1 include organization of chromosomal structure, DNA recombination or gene regulation, all of which could be relevant in CRISPR-Cas functionality. Results The CRISPR1 repeat-spacer array contains more than 50 CGATCG elements that are double-methylated (5mCG6mATCG) by the enzymes M.Ssp6803I and M.Ssp6803III. Hence, more than 200 possible methylation events cluster over a stretch of 3600 bp of double-stranded DNA. Bisulfite sequencing showed that these motifs were highly methylated at the m5CGATCG positions whereas specific motifs within the CRISPR1 cas genes were hypomethylated suggesting a lowered accessibility for the DNA methylase to these regions. Assays for conjugation and CRISPR1-mediated DNA interference revealed a 50% drop in conjugation efficiency in the mutant lacking the 5mC methylation of CGATCG motifs, while the highly efficient DNA interference activity was not affected by the lack of m5CGATCG DNA-methylation, nor was the capability to differentiate between self and non-self targets based on the protospacer adjacent motifs (PAMs) GTA and GTC versus the non-PAM AGC. A third DNA methylation mediated by M.Ssp6803II modifies the first cytosine in the motif GGCC yielding GGm4CC. We found a remarkable absence of GGCC motifs and hence the corresponding methylation over an 11 kb stretch encompassing all the cas genes involved in interference and crRNA maturation but not adaptation of the CRISPR1 system. Conclusions The lack of GGCC tetranucleotides along the CRISPR1 interference and maturation genes supports the reported hybrid character of subtype I-D CRISPR-Cas systems. We report tight and very high 5mC methylation of the CRISPR1 repeat sequences. Nevertheless, cells lacking the 5mC methylation activity were unaffected in their CRISPR1-mediated interference response but the efficiency of conjugation was reduced by 50%. These results point to an unknown role of m5CGATCG DNA-methylation marks in conjugation and DNA transformation.
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Affiliation(s)
- Ingeborg Scholz
- Faculty of Biology, Genetics an Experimental Bioinformatics, University of Freiburg, Schänzlestr. 1, D-79104, Freiburg, Germany
| | - Steffen C Lott
- Faculty of Biology, Genetics an Experimental Bioinformatics, University of Freiburg, Schänzlestr. 1, D-79104, Freiburg, Germany
| | - Juliane Behler
- Faculty of Biology, Genetics an Experimental Bioinformatics, University of Freiburg, Schänzlestr. 1, D-79104, Freiburg, Germany
| | - Katrin Gärtner
- University of Rostock, Institute of Biosciences, Plant Physiology, A.-Einstein-Str. 3, D-18059, Rostock, Germany
| | - Martin Hagemann
- University of Rostock, Institute of Biosciences, Plant Physiology, A.-Einstein-Str. 3, D-18059, Rostock, Germany
| | - Wolfgang R Hess
- Faculty of Biology, Genetics an Experimental Bioinformatics, University of Freiburg, Schänzlestr. 1, D-79104, Freiburg, Germany. .,University of Freiburg, Freiburg Institute for Advanced Studies, Albertstr. 19, D-79104, Freiburg, Germany.
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Klähn S, Bolay P, Wright PR, Atilho RM, Brewer KI, Hagemann M, Breaker RR, Hess WR. A glutamine riboswitch is a key element for the regulation of glutamine synthetase in cyanobacteria. Nucleic Acids Res 2019; 46:10082-10094. [PMID: 30085248 PMCID: PMC6212724 DOI: 10.1093/nar/gky709] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 07/25/2018] [Indexed: 12/19/2022] Open
Abstract
As the key enzyme of bacterial nitrogen assimilation, glutamine synthetase (GS) is tightly regulated. In cyanobacteria, GS activity is controlled by the interaction with inactivating protein factors IF7 and IF17 encoded by the genes gifA and gifB, respectively. We show that a glutamine-binding aptamer within the gifB 5′ UTR of Synechocystis sp. PCC 6803 is critical for the expression of IF17. Binding of glutamine induced structural re-arrangements in this RNA element leading to enhanced protein synthesis in vivo and characterizing it as a riboswitch. Mutagenesis showed the riboswitch mechanism to contribute at least as much to the control of gene expression as the promoter-mediated transcriptional regulation. We suggest this and a structurally related but distinct element, to be designated type 1 and type 2 glutamine riboswitches. Extended biocomputational searches revealed that glutamine riboswitches are exclusively but frequently found in cyanobacterial genomes, where they are primarily associated with gifB homologs. Hence, this RNA-based sensing mechanism is common in cyanobacteria and establishes a regulatory feedback loop that couples the IF17-mediated GS inactivation to the intracellular glutamine levels. Together with the previously described sRNA NsiR4, these results show that non-coding RNA is an indispensable component in the control of nitrogen assimilation in cyanobacteria.
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Affiliation(s)
- Stephan Klähn
- Genetics & Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Freiburg, Germany.,Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA.,Department of Solar Materials, Helmholtz-Centre for Environmental Research, Leipzig, Germany
| | - Paul Bolay
- Genetics & Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Patrick R Wright
- Bioinformatics, Technical Faculty, University of Freiburg, Freiburg, Germany
| | - Ruben M Atilho
- Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Kenneth I Brewer
- Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Martin Hagemann
- Department of Plant Physiology, Institute of Biological Sciences, University of Rostock, Rostock, Germany
| | - Ronald R Breaker
- Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA.,Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University, New Haven, CT, USA
| | - Wolfgang R Hess
- Genetics & Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Freiburg, Germany.,Freiburg Institute for Advanced Studies, University of Freiburg, Germany
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Gärtner K, Klähn S, Watanabe S, Mikkat S, Scholz I, Hess WR, Hagemann M. Cytosine N4-Methylation via M.Ssp6803II Is Involved in the Regulation of Transcription, Fine- Tuning of DNA Replication and DNA Repair in the Cyanobacterium Synechocystis sp. PCC 6803. Front Microbiol 2019; 10:1233. [PMID: 31231331 PMCID: PMC6560206 DOI: 10.3389/fmicb.2019.01233] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 05/17/2019] [Indexed: 12/15/2022] Open
Abstract
DNA methylation plays a crucial role for gene regulation among eukaryotes, but its regulatory function is less documented in bacteria. In the cyanobacterium Synechocystis sp. PCC 6803 five DNA methyltransferases have been identified. Among them, M.Ssp6803II is responsible for the specific methylation of the first cytosine in the frequently occurring motif GGCC, leading to N4-methylcytosine (GGm4CC). The mutation of the corresponding gene sll0729 led to lowered chlorophyll/phycocyanin ratio and slower growth. Transcriptomics only showed altered expression of sll0470 and sll1526, two genes encoding hypothetical proteins. Moreover, prolonged cultivation revealed instability of the initially obtained phenotype. Colonies with normal pigmentation and wild-type-like growth regularly appeared on agar plates. These colonies represent suppressor mutants, because the sll0729 gene was still completely inactivated and the GGCC sites remained unmethylated. The suppressor strains showed smaller cell size, lowered DNA content per cell, and decreased tolerance against UV compared to wild type. Promoter assays revealed that the transcription of the sll0470 gene was still stimulated in the suppressor clones. Proteomics identified decreased levels of DNA topoisomerase 4 subunit A in suppressor cells. Collectively, these results indicate that GGm4CC methylation is involved in the regulation of gene expression, in the fine-tuning of DNA replication, and DNA repair mechanisms.
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Affiliation(s)
- Katrin Gärtner
- Department of Plant Physiology, University of Rostock, Rostock, Germany
| | - Stephan Klähn
- Faculty of Biology, Genetics & Experimental Bioinformatics, University of Freiburg, Freiburg im Breisgau, Germany
- Department of Solar Materials, Helmholtz-Centre for Environmental Research, Leipzig, Germany
| | - Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Stefan Mikkat
- Core Facility Proteome Analysis, University Medicine Rostock, Rostock, Germany
| | - Ingeborg Scholz
- Faculty of Biology, Genetics & Experimental Bioinformatics, University of Freiburg, Freiburg im Breisgau, Germany
| | - Wolfgang R. Hess
- Faculty of Biology, Genetics & Experimental Bioinformatics, University of Freiburg, Freiburg im Breisgau, Germany
- Freiburg Institute for Advanced Studies, University of Freiburg, Freiburg im Breisgau, Germany
| | - Martin Hagemann
- Department of Plant Physiology, University of Rostock, Rostock, Germany
- Department Life, Light and Matter, University of Rostock, Rostock, Germany
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Hagemann M, Henneberg M, Felde VJMNL, Berkowicz SM, Raanan H, Pade N, Felix-Henningsen P, Kaplan A. Cyanobacterial populations in biological soil crusts of the northwest Negev Desert, Israel-effects of local conditions and disturbance. FEMS Microbiol Ecol 2019; 93:2617556. [PMID: 27810874 DOI: 10.1093/femsec/fiw228] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 11/02/2016] [Indexed: 11/14/2022] Open
Abstract
Biological soil crusts (BSCs) fulfil numerous ecological functions in arid and semiarid areas. Cyanobacteria are important BSC organisms, which are responsible for carbon fixation, N2 fixation and binding of soil via extracellular polysaccharides. The cyanobacterial populations were characterised in different sampling plots established in three experimental stations along a rainfall gradient within NW Negev Desert, Israel. Cyanobacterial crust thickness and osmolyte accumulation therein decreased in plots with lower moisture. The cyanobacterial population structure also changed in different plots. We observed an increase of subsection III cyanobacteria such as Microcoleus spp. and Leptolyngbya spp. and a decreasing proportion of strains belonging to subsections I and IV in drier areas on the rainfall gradient. This population shift was also observed in the sampling plots, which were situated at various relief positions within the sand dune experimental sites. We also characterised the cyanobacterial populations within mechanically disturbed plots. After 4 years, they reached between 80% and 50% of the control populations in the northernmost and southern stations, respectively. Our results suggest that the cyanobacterial population is sensitive not only to macroscale factors but may also be subject to local climate variations and that 4 years was insufficient for complete recovery of the cyanobacterial population.
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Affiliation(s)
- Martin Hagemann
- Institut für Biowissenschaften, Abteilung Pflanzenphysiologie, Universität Rostock, A.-Einstein-Str. 3, D-18059 Rostock, Germany
| | - Manja Henneberg
- Institut für Biowissenschaften, Abteilung Pflanzenphysiologie, Universität Rostock, A.-Einstein-Str. 3, D-18059 Rostock, Germany
| | - Vincent J M N L Felde
- Institute for Soil Science and Soil Conservation, IFZ-Research Centre for BioSystems, Land Use and Nutrition, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 26, D-35392 Gießen, Germany.,Department of Soil Science, Faculty of Organic Agricultural Sciences, University of Kassel, Nordbahnhofstr. 1A, D-37213 Witzenhausen, Germany
| | - Simon M Berkowicz
- Department of Plant and Environmental Sciences, Edmond J. Safra Campus - Givat Ram, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.,Arid Ecosystems Research Center, Edmond J. Safra Campus- Givat Ram, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Hagai Raanan
- Institute of Marine and Coastal Sciences, Rutgers University, 71 Dudley Road, New Brunswick, NJ 08901, USA
| | - Nadin Pade
- Institut für Biowissenschaften, Abteilung Pflanzenphysiologie, Universität Rostock, A.-Einstein-Str. 3, D-18059 Rostock, Germany
| | - Peter Felix-Henningsen
- Institute for Soil Science and Soil Conservation, IFZ-Research Centre for BioSystems, Land Use and Nutrition, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 26, D-35392 Gießen, Germany
| | - Aaron Kaplan
- Department of Plant and Environmental Sciences, Edmond J. Safra Campus - Givat Ram, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.,Arid Ecosystems Research Center, Edmond J. Safra Campus- Givat Ram, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
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Reinholdt O, Bauwe H, Hagemann M, Timm S. Redox-regulation of mitochondrial metabolism through thioredoxin o1 facilitates light induction of photosynthesis. Plant Signal Behav 2019; 14:1674607. [PMID: 31589099 PMCID: PMC6866678 DOI: 10.1080/15592324.2019.1674607] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Despite the well-known biochemistry of the major pathways involved in central carbon and amino acid metabolism, there are still gaps regarding their regulation or regulatory interactions. Recent research demonstrated the physiological significance of the mitochondrial redox machinery, particularly thioredoxin o1 (TRXo1), for proper regulation of the tricarboxylic acid cycle, components of the mitochondrial electron transport chain and photorespiration. These findings imply that TRXo1 regulation contributes to the metabolic acclimation toward changes in the prevailing environmental conditions. Here, we analyzed if TRXo1 is involved in the light induction of photosynthesis. Our results show that the trxo1 mutant activates CO2 assimilation rates to a significantly lower extend than wild type in response to short-term light/dark changes. Metabolite analysis suggests that activation of glycine-to-serine conversion catalyzed through glycine decarboxylase in conjunction with serine hydroxymethyltransferase in trxo1 is slowed down at onset of illumination. We propose that redox regulation via TRXo1 is necessary to allow the rapid induction of mitochondrial steps of the photorespiratory cycle and, in turn, to facilitate light-induction of photosynthesis.
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Affiliation(s)
- Ole Reinholdt
- Plant Physiology Department, University of Rostock, Rostock, Germany
| | - Hermann Bauwe
- Plant Physiology Department, University of Rostock, Rostock, Germany
| | - Martin Hagemann
- Plant Physiology Department, University of Rostock, Rostock, Germany
| | - Stefan Timm
- Plant Physiology Department, University of Rostock, Rostock, Germany
- CONTACT Stefan Timm Plant Physiology Department, University of Rostock, Rostock, Germany
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Haider F, Sokolov EP, Timm S, Hagemann M, Blanco Rayón E, Marigómez I, Izagirre U, Sokolova IM. Interactive effects of osmotic stress and burrowing activity on protein metabolism and muscle capacity in the soft shell clam Mya arenaria. Comp Biochem Physiol A Mol Integr Physiol 2018; 228:81-93. [PMID: 30445227 DOI: 10.1016/j.cbpa.2018.10.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 10/28/2018] [Accepted: 10/29/2018] [Indexed: 01/28/2023]
Abstract
Bioturbators such as sediment-dwelling marine bivalves are ecosystem engineers that enhance sediment-water exchange and benthic-pelagic coupling. In shallow coastal areas, bivalves are exposed to frequent disturbance and salinity stress that might negatively affect their activity and physiological performance; however, the mechanisms underlying these effects are not fully understood. We investigated the effects of osmotic stress (low and fluctuating salinity) and repeated burrowing on aerobic and contractile capacity of the foot muscle (assessed by the activity of succinate dehydrogenase and myosin ATPase) as well as the levels of organic osmolytes (free amino acids) and biochemical markers of protein synthesis and proteolysis in key osmoregulatory and energy storing tissues (gills and hepatopancreas, respectively) in a common bioturbator, the soft shell clam Mya arenaria. Osmotic stress and exhaustive exercise altered the foot muscle capacity of soft shell clams and had a strong impact on protein and amino acid homeostasis in tissues not directly involved in locomotion. Acclimation to constant low salinity (5 practical salinity units) depleted the whole-body free amino acid pool and affected protein synthesis but not protein breakdown in the gill. In contrast, fluctuating (5-15) salinity increased protein breakdown rate, suppressed protein synthesis, caused oxidative damage to proteins in the gill and selectively depleted whole-body glycine pool. Clams acclimated to normal salinity (15) increased the aerobic capacity of the foot muscle upon repeated burrowing, whereas acclimation to low and fluctuating salinity reduced this adaptive muscle plasticity. Under the normal and low salinity conditions, exhaustive exercise induced protein conservation pathways (indicated by suppression of protein synthesis and catabolism), but this effect was disrupted by fluctuating salinity. These findings indicate that exhaustive exercise and osmotic stress interactively affect whole-body protein homeostasis and functional capacity of the foot muscle in soft shell clams which might contribute to reduced burrowing activity of bivalve bioturbators in osmotically challenging environments such as estuaries and shallow coastal zones.
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Affiliation(s)
- Fouzia Haider
- Department of Marine Biology, University of Rostock, Rostock, Germany
| | - Eugene P Sokolov
- Leibniz Institute for Baltic Sea Research, Leibniz ScienceCampus Phosphorus Research Rostock, Warnemünde, Germany; Department of Applied Ecology, University of Rostock, Rostock, Germany
| | - Stefan Timm
- Department of Plant Physiology, University of Rostock, Rostock, Germany
| | - Martin Hagemann
- Department of Plant Physiology, University of Rostock, Rostock, Germany
| | - Esther Blanco Rayón
- Research Centre for Experimental Marine Biology and Biotechnology, University of the Basque Country, Plentzia, Bizkaia, Spain
| | - Ionan Marigómez
- Research Centre for Experimental Marine Biology and Biotechnology, University of the Basque Country, Plentzia, Bizkaia, Spain
| | - Urtzi Izagirre
- Research Centre for Experimental Marine Biology and Biotechnology, University of the Basque Country, Plentzia, Bizkaia, Spain
| | - Inna M Sokolova
- Department of Marine Biology, University of Rostock, Rostock, Germany; Department of Maritime Systems, Interdisciplinary Faculty, University of Rostock, Rostock, Germany.
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Kirsch F, Luo Q, Lu X, Hagemann M. Inactivation of invertase enhances sucrose production in the cyanobacterium Synechocystis sp. PCC 6803. Microbiology (Reading) 2018; 164:1220-1228. [PMID: 30113304 DOI: 10.1099/mic.0.000708] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Sucrose is naturally synthesized by many cyanobacteria under high salt conditions, which can be applied to produce this widely used feedstock. To improve sucrose production with the moderate halo-tolerant cyanobacterium Synechocystis sp. PCC 6803, we identified and biochemically characterized the sucrose-degrading invertase. Inactivating the invertase encoding gene sll0626 (inv) significantly increased cellular sucrose levels; interestingly sucrose over-accumulation was also observed under NaCl-free conditions. The subsequent inactivation of inv in the mutant ΔggpS, which cannot synthesize the major compatible solute glucosylglycerol, resulted in further enhanced sucrose accumulation in the presence of 1.5 % NaCl. Then, inv mutation was introduced into the previously obtained sucrose-producing strain WD25 (Du W, Liang F, Duan Y, Tan X, Lu X. Metab Eng 2013;19:17-25), which resulted in almost 40 % higher sucrose accumulation. These findings show that invertase is an interesting target in obtaining efficient sucrose production in cyanobacterial host cells.
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Affiliation(s)
- Friedrich Kirsch
- 1Department of Plant Physiology, Institute of Biological Sciences, University of Rostock, Albert-Einstein-Str. 3, 18059 Rostock, Germany
| | - Quan Luo
- 2Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101, PR China
| | - Xuefeng Lu
- 2Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101, PR China.,3Marine biology and Biotechnology Laboratory, Qingdao National Laboratory for Marine Science and Technology, Wenhai Rd 1, Aoshanwei, Qingdao, PR China
| | - Martin Hagemann
- 4Department Life, Light & Matter, University of Rostock, 18051 Rostock, Germany.,1Department of Plant Physiology, Institute of Biological Sciences, University of Rostock, Albert-Einstein-Str. 3, 18059 Rostock, Germany
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Hagemann M, Gärtner K, Scharnagl M, Bolay P, Lott SC, Fuss J, Huettel B, Reinhardt R, Klähn S, Hess WR. Identification of the DNA methyltransferases establishing the methylome of the cyanobacterium Synechocystis sp. PCC 6803. DNA Res 2018; 25:343-352. [PMID: 29444255 PMCID: PMC6105098 DOI: 10.1093/dnares/dsy006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 01/24/2018] [Indexed: 11/12/2022] Open
Abstract
DNA methylation in bacteria is important for defense against foreign DNA, but is also involved in DNA repair, replication, chromosome partitioning, and regulatory processes. Thus, characterization of the underlying DNA methyltransferases in genetically tractable bacteria is of paramount importance. Here, we characterized the methylome and orphan methyltransferases in the model cyanobacterium Synechocystis sp. PCC 6803. Single molecule real-time (SMRT) sequencing revealed four DNA methylation recognition sequences in addition to the previously known motif m5CGATCG, which is recognized by M.Ssp6803I. For three of the new recognition sequences, we identified the responsible methyltransferases. M.Ssp6803II, encoded by the sll0729 gene, modifies GGm4CC, M.Ssp6803III, encoded by slr1803, represents the cyanobacterial dam-like methyltransferase modifying Gm6ATC, and M.Ssp6803V, encoded by slr6095 on plasmid pSYSX, transfers methyl groups to the bipartite motif GGm6AN7TTGG/CCAm6AN7TCC. The remaining methylation recognition sequence GAm6AGGC is probably recognized by methyltransferase M.Ssp6803IV encoded by slr6050. M.Ssp6803III and M.Ssp6803IV were essential for the viability of Synechocystis, while the strains lacking M.Ssp6803I and M.Ssp6803V showed growth similar to the wild type. In contrast, growth was strongly diminished of the Δsll0729 mutant lacking M.Ssp6803II. These data provide the basis for systematic studies on the molecular mechanisms impacted by these methyltransferases.
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Affiliation(s)
- Martin Hagemann
- Institute of Biosciences, Plant Physiology, University of Rostock, Rostock, Germany
| | - Katrin Gärtner
- Institute of Biosciences, Plant Physiology, University of Rostock, Rostock, Germany
| | - Matthias Scharnagl
- Institute of Biosciences, Plant Physiology, University of Rostock, Rostock, Germany
| | - Paul Bolay
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Steffen C Lott
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Janina Fuss
- Max Planck-Genome-Centre Cologne, Max Planck Institute for Plant Breeding Research, Köln, Germany
| | - Bruno Huettel
- Max Planck-Genome-Centre Cologne, Max Planck Institute for Plant Breeding Research, Köln, Germany
| | - Richard Reinhardt
- Max Planck-Genome-Centre Cologne, Max Planck Institute for Plant Breeding Research, Köln, Germany
| | - Stephan Klähn
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Wolfgang R Hess
- Faculty of Biology, University of Freiburg, Freiburg, Germany
- Freiburg Institute for Advanced Studies, University of Freiburg, Germany
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Nishiyama T, Sakayama H, de Vries J, Buschmann H, Saint-Marcoux D, Ullrich KK, Haas FB, Vanderstraeten L, Becker D, Lang D, Vosolsobě S, Rombauts S, Wilhelmsson PK, Janitza P, Kern R, Heyl A, Rümpler F, Villalobos LIAC, Clay JM, Skokan R, Toyoda A, Suzuki Y, Kagoshima H, Schijlen E, Tajeshwar N, Catarino B, Hetherington AJ, Saltykova A, Bonnot C, Breuninger H, Symeonidi A, Radhakrishnan GV, Van Nieuwerburgh F, Deforce D, Chang C, Karol KG, Hedrich R, Ulvskov P, Glöckner G, Delwiche CF, Petrášek J, Van de Peer Y, Friml J, Beilby M, Dolan L, Kohara Y, Sugano S, Fujiyama A, Delaux PM, Quint M, Theißen G, Hagemann M, Harholt J, Dunand C, Zachgo S, Langdale J, Maumus F, Van Der Straeten D, Gould SB, Rensing SA. The Chara Genome: Secondary Complexity and Implications for Plant Terrestrialization. Cell 2018; 174:448-464.e24. [DOI: 10.1016/j.cell.2018.06.033] [Citation(s) in RCA: 271] [Impact Index Per Article: 45.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 03/27/2018] [Accepted: 06/14/2018] [Indexed: 01/11/2023]
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Rübsam H, Kirsch F, Reimann V, Erban A, Kopka J, Hagemann M, Hess WR, Klähn S. The iron-stress activated RNA 1 (IsaR1) coordinates osmotic acclimation and iron starvation responses in the cyanobacterium Synechocystis sp. PCC 6803. Environ Microbiol 2018; 20:2757-2768. [PMID: 29468839 DOI: 10.1111/1462-2920.14079] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 02/18/2018] [Indexed: 11/28/2022]
Abstract
In nature, microorganisms are exposed to multiple stress factors in parallel. Here, we investigated the response of the model cyanobacterium Synechocystis sp. PCC 6803 to simultaneous iron limitation and osmotic stresses. Iron is a major limiting factor for bacterial and phytoplankton growth in most environments. Thus, bacterial iron homeostasis is tightly regulated. In Synechocystis, it is mediated mainly by the transcriptional regulator FurA and the iron-stress activated RNA 1 (IsaR1). IsaR1 is an important riboregulator that affects the acclimation of the photosynthetic apparatus to iron starvation in multiple ways. Upon increases in salinity, Synechocystis responds by accumulating the compatible solute glucosylglycerol (GG). We show that IsaR1 overexpression causes a reduction in the de novo GG synthesis rate upon salt shock. We verified the direct interaction between IsaR1 and the 5'UTR of the ggpS mRNA, which in turn drastically reduced the de novo synthesis of the key enzyme for GG synthesis, glucosylglycerol phosphate synthase (GgpS). Thus, IsaR1 specifically interferes with the salt acclimation process in Synechocystis, in addition to its primary regulatory function. Moreover, the salt-stimulated GgpS production became reduced under parallel iron limitation in WT - an effect which is, however, attenuated in an isaR1 deletion strain. Hence, IsaR1 is involved in the integration of the responses to different environmental perturbations and slows the osmotic adaptation process in cells suffering from parallel iron starvation.
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Affiliation(s)
- Henriette Rübsam
- Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, University of Freiburg, D-79104 Freiburg, Germany
| | - Friedrich Kirsch
- Plant Physiology department, A.-Einstein-Str. 3, University of Rostock, Institute of Biological Sciences, D-18059 Rostock, Germany
| | - Viktoria Reimann
- Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, University of Freiburg, D-79104 Freiburg, Germany
| | - Alexander Erban
- Department of Molecular Physiology: Applied Metabolome Analysis, Am Mühlenberg 1, Max-Planck-Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany
| | - Joachim Kopka
- Department of Molecular Physiology: Applied Metabolome Analysis, Am Mühlenberg 1, Max-Planck-Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany
| | - Martin Hagemann
- Plant Physiology department, A.-Einstein-Str. 3, University of Rostock, Institute of Biological Sciences, D-18059 Rostock, Germany
| | - Wolfgang R Hess
- Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, University of Freiburg, D-79104 Freiburg, Germany
| | - Stephan Klähn
- Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, University of Freiburg, D-79104 Freiburg, Germany
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Rai S, Lucius S, Kern R, Bauwe H, Kaplan A, Kopka J, Hagemann M. The Synechocystis sp. PCC 6803 Genome Encodes Up to Four 2-Phosphoglycolate Phosphatases. Front Plant Sci 2018; 9:1718. [PMID: 30542360 PMCID: PMC6278635 DOI: 10.3389/fpls.2018.01718] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 11/05/2018] [Indexed: 05/07/2023]
Abstract
Photorespiratory phosphoglycolate (2PG) metabolism is essential for cyanobacteria, algae, and plants. The first enzyme of the pathway, 2PG phosphatase (PGPase), is known from plants and algae but was scarcely investigated in cyanobacteria. In silico analysis revealed four candidate genes (slr0458, slr0586, sll1349, and slr1762) in the genome of the model cyanobacterium Synechocystis sp. PCC 6803 that all belong to the 2-haloacid dehalogenase (HAD) superfamily and could possibly encode PGPase proteins. However, in contrast to known algal and plant PGPases, the putative cyanobacterial PGPases belong to another HAD subfamily implying that PGPases in eukaryotic phototrophs did not originate from cyanobacterial PGPases. To verify their function, these four genes were inactivated both individually and in combination. A mild high-CO2-requiring (HCR) growth phenotype typical for photorespiratory mutants was observed only in Δsll1349. Combinatorial inactivation enhanced the HCR phenotype in specific double and triple mutants. Heterologous expression of the putative cyanobacterial PGPases in E. coli led to higher PGPase activities in crude cell extracts, but only the purified Slr0458 protein showed PGPase activity. Hence, we propose that a consortium of up to four photorespiratory PGPases may initiate photorespiratory 2PG metabolism in Synechocystis. We suggest that redundancy of this essential enzyme activity could be related to the highly adaptive lifestyle of cyanobacteria such as Synechocystis sp. PCC 6803, which allows them to grow under very diverse conditions.
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Affiliation(s)
- Snigdha Rai
- Department of Plant Physiology, University of Rostock, Rostock, Germany
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, India
| | - Stefan Lucius
- Department of Plant Physiology, University of Rostock, Rostock, Germany
| | - Ramona Kern
- Department of Plant Physiology, University of Rostock, Rostock, Germany
| | - Hermann Bauwe
- Department of Plant Physiology, University of Rostock, Rostock, Germany
| | - Aaron Kaplan
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Joachim Kopka
- Applied Metabolome Analysis, Department of Molecular Physiology, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Martin Hagemann
- Department of Plant Physiology, University of Rostock, Rostock, Germany
- Department Life, Light and Matter, University of Rostock, Rostock, Germany
- *Correspondence: Martin Hagemann,
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Kirsch F, Pade N, Klähn S, Hess WR, Hagemann M. The glucosylglycerol-degrading enzyme GghA is involved in acclimation to fluctuating salinities by the cyanobacterium Synechocystis sp. strain PCC 6803. Microbiology (Reading) 2017; 163:1319-1328. [PMID: 28857041 DOI: 10.1099/mic.0.000518] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The ggpS gene, which encodes the key enzyme for the synthesis of the compatible solute glucosylglycerol (GG), has a promoter region that overlaps with the upstream-located gene slr1670 in the cyanobacterium Synechocystissp. PCC 6803. Like ggpS, the slr1670 gene is salt-induced and encodes a putative glucosylhydrolase. A mutant strain with a slr1670 deletion was generated and found to be unable to adapt the internal GG concentrations in response to changes in external salinities. Whereas cells of the wild-type reduced the internal pool of GG when exposed to gradual and abrupt hypo-osmotic treatments, or when the compatible solute trehalose was added to the growth medium, the internal GG pool of ∆slr1670 mutant cells remained unchanged. These findings indicated that the protein Slr1670 is involved in GG breakdown. The biochemical activity of this GG-hydrolase enzyme was verified using recombinant Slr1670 protein, which split GG into glucose and glycerol. These results validate that Slr1670, which was named GghA, acts as a GG hydrolase. GghA is involved in GG turnover in fluctuating salinities, and similar proteins are found in the genomes of other GG-synthesizing cyanobacteria.
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Affiliation(s)
- Friedrich Kirsch
- University of Rostock, Institute for Biowissenschaften, Abt. Pflanzenphysiologie, A.-Einstein-Str. 3, D-18059 Rostock, Germany
| | - Nadin Pade
- University of Rostock, Institute for Biowissenschaften, Abt. Pflanzenphysiologie, A.-Einstein-Str. 3, D-18059 Rostock, Germany
| | - Stephan Klähn
- Genetics and Experimental Bioinformatics, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Wolfgang R Hess
- Genetics and Experimental Bioinformatics, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Martin Hagemann
- University of Rostock, Institute for Biowissenschaften, Abt. Pflanzenphysiologie, A.-Einstein-Str. 3, D-18059 Rostock, Germany
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Hagemann M, Hess WR. Systems and synthetic biology for the biotechnological application of cyanobacteria. Curr Opin Biotechnol 2017; 49:94-99. [PMID: 28843192 DOI: 10.1016/j.copbio.2017.07.008] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 07/13/2017] [Accepted: 07/17/2017] [Indexed: 10/19/2022]
Abstract
Cyanobacteria are the only prokaryotes that perform oxygenic photosynthesis. Their evolutionary relation to plastids in eukaryotic phototrophs and their increasing utilization as green cell factories initiated the use of systems biology approaches early on. For select model strains, extensive 'omics' data sets have been generated, and genome-wide models have been elucidated. Moreover, the results obtained may be used for the optimization of cyanobacterial metabolism, which can direct the biotechnological production of biofuels or chemical feedstock. Synthetic biology approaches permit the rational construction of novel metabolic pathways that are based on the combination of multiple enzymatic activities of different origins. In addition, the manipulation of whole metabolic networks by CRISPR-based and sRNA-based technologies with multiple parallel targets will further stimulate the use of cyanobacteria for diverse applications in basic research and biotechnology.
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Affiliation(s)
- Martin Hagemann
- University of Rostock, Institute of Biological Sciences, Plant Physiology, A.-Einstein-Str. 3, D-18059 Rostock, Germany.
| | - Wolfgang R Hess
- University of Freiburg, Faculty of Biology, Schänzlestr. 1, D-79104 Freiburg, Germany
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50
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Song K, Hagemann M, Tan X, Lu X. The Response Regulator Slr1588 Regulates spsA But Is Not Crucial for Salt Acclimation of Synechocystis sp. PCC 6803. Front Microbiol 2017; 8:1176. [PMID: 28694802 PMCID: PMC5483463 DOI: 10.3389/fmicb.2017.01176] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 06/09/2017] [Indexed: 11/13/2022] Open
Abstract
Cyanobacterial sucrose biosynthesis is stimulated under salt stress, which could be used for biotechnological sugar production. It has been shown that the response regulator Slr1588 negatively regulates the spsA gene encoding sucrose-phosphate synthase and mutation of the slr1588 gene also affected the salt tolerance of Synechocystis (Chen et al., 2014). The latter finding is contrary to earlier observations (Hagemann et al., 1997b). Here, we observed that ectopic expression of slr1588 did not restore the salt tolerance of the slr1588 mutant, making the essential function of this response regulator for salt tolerance questionable. Subsequent experiments showed that deletion of the entire coding sequence of slr1588 compromised the expression of the downstream situated ggpP gene, which encodes glucosylglycerol-phosphate phosphatase for synthesis of the primary osmolyte glucosylglycerol. Mutation of slr1588 by deleting the N-terminal part of this protein (Δslr1588-F976) did not affect ggpP expression, glucosylglycerol accumulation as well as salt tolerance, while the mutation of ggpP resulted in the previously reported salt-sensitive phenotype. In the Δslr1588-F976 mutant spsA was up-regulated but sucrose content was lowered due to increased invertase activity. Our results reveal that Slr1588 is acting as a repressor for spsA as previously suggested but it is not crucial for the overall salt acclimation of Synechocystis.
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Affiliation(s)
- Kuo Song
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdao, China
| | - Martin Hagemann
- Department of Plant Physiology, Institute of Biological Sciences, University of RostockRostock, Germany
| | - Xiaoming Tan
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdao, China
| | - Xuefeng Lu
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and TechnologyQingdao, China
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