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Vergara-Barros P, Alcorta J, Casanova-Katny A, Nürnberg DJ, Díez B. Compensatory Transcriptional Response of Fischerella thermalis to Thermal Damage of the Photosynthetic Electron Transfer Chain. Molecules 2022; 27:8515. [PMID: 36500606 PMCID: PMC9740203 DOI: 10.3390/molecules27238515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 11/29/2022] [Accepted: 11/29/2022] [Indexed: 12/11/2022] Open
Abstract
Key organisms in the environment, such as oxygenic photosynthetic primary producers (photosynthetic eukaryotes and cyanobacteria), are responsible for fixing most of the carbon globally. However, they are affected by environmental conditions, such as temperature, which in turn affect their distribution. Globally, the cyanobacterium Fischerella thermalis is one of the main primary producers in terrestrial hot springs with thermal gradients up to 60 °C, but the mechanisms by which F. thermalis maintains its photosynthetic activity at these high temperatures are not known. In this study, we used molecular approaches and bioinformatics, in addition to photophysiological analyses, to determine the genetic activity associated with the energy metabolism of F. thermalis both in situ and in high-temperature (40 °C to 65 °C) cultures. Our results show that photosynthesis of F. thermalis decays with temperature, while increased transcriptional activity of genes encoding photosystem II reaction center proteins, such as PsbA (D1), could help overcome thermal damage at up to 60 °C. We observed that F. thermalis tends to lose copies of the standard G4 D1 isoform while maintaining the recently described D1INT isoform, suggesting a preference for photoresistant isoforms in response to the thermal gradient. The transcriptional activity and metabolic characteristics of F. thermalis, as measured by metatranscriptomics, further suggest that carbon metabolism occurs in parallel with photosynthesis, thereby assisting in energy acquisition under high temperatures at which other photosynthetic organisms cannot survive. This study reveals that, to cope with the harsh conditions of hot springs, F. thermalis has several compensatory adaptations, and provides emerging evidence for mixotrophic metabolism as being potentially relevant to the thermotolerance of this species. Ultimately, this work increases our knowledge about thermal adaptation strategies of cyanobacteria.
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Affiliation(s)
- Pablo Vergara-Barros
- Department of Molecular Genetics and Microbiology, Biological Sciences Faculty, Pontifical Catholic University of Chile, Santiago 8331150, Chile
- Millennium Institute Center for Genome Regulation (CGR), Santiago 8370186, Chile
| | - Jaime Alcorta
- Department of Molecular Genetics and Microbiology, Biological Sciences Faculty, Pontifical Catholic University of Chile, Santiago 8331150, Chile
| | - Angélica Casanova-Katny
- Laboratory of Plant Ecophysiology, Faculty of Natural Resources, Campus Luis Rivas del Canto, Catholic University of Temuco, Temuco 4780000, Chile
| | - Dennis J. Nürnberg
- Institute of Experimental Physics, Freie Universität Berlin, 14195 Berlin, Germany
- Dahlem Centre of Plant Sciences, Freie Universität Berlin, 14195 Berlin, Germany
| | - Beatriz Díez
- Department of Molecular Genetics and Microbiology, Biological Sciences Faculty, Pontifical Catholic University of Chile, Santiago 8331150, Chile
- Millennium Institute Center for Genome Regulation (CGR), Santiago 8370186, Chile
- Center for Climate and Resilience Research (CR)2, Santiago 8370449, Chile
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Kim Tiam S, Comte K, Dalle C, Delagrange M, Djediat C, Ducos B, Duval C, Feilke K, Hamlaoui S, Le Manach S, Setif P, Yéprémian C, Marie B, Kirilovsky D, Gugger M, Bernard C. The success of the bloom-forming cyanobacteria Planktothrix: Genotypes variability supports variable responses to light and temperature stress. HARMFUL ALGAE 2022; 117:102285. [PMID: 35944963 DOI: 10.1016/j.hal.2022.102285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 05/05/2022] [Accepted: 06/28/2022] [Indexed: 06/15/2023]
Abstract
Cyanobacterial blooms can modify the dynamic of aquatic ecosystems and have harmful consequences for human activities. Moreover, cyanobacteria can produce a variety of cyanotoxins, including microcystins, but little is known about the role of environmental factors on the prevalence of microcystin producers in the cyanobacterial bloom dynamics. This study aimed to better understand the success of Planktothrix in various environments by unveiling the variety of strategies governing cell responses to sudden changes in light intensity and temperature. The cellular responses (photosynthesis, photoprotection, heat shock response and metabolites synthesis) of four Planktothrix strains to high-light or high-temperature were studied, focusing on how distinct ecotypes (red- or green-pigmented) and microcystin production capability affect cyanobacteria's ability to cope with such abiotic stimuli. Our results showed that high-light and high-temperature impact different cellular processes and that Planktothrix responses are heterogeneous, specific to each strain and thus, to genotype. The ability of cyanobacteria to cope with sudden increase in light intensity and temperature was not related to red- or green-pigmented ecotype or microcystin production capability. According to our results, microcystin producers do not cope better to high-light or high-temperature and microcystin content does not increase in response to such stresses.
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Affiliation(s)
- Sandra Kim Tiam
- UMR 7245 Molécules de Communication et Adaptations des Microorganismes (MCAM), Muséum National d'Histoire Naturelle, CNRS, CP 39, 57 rue Cuvier, Paris, 75005, France.
| | - Katia Comte
- UMR 7245 Molécules de Communication et Adaptations des Microorganismes (MCAM), Muséum National d'Histoire Naturelle, CNRS, CP 39, 57 rue Cuvier, Paris, 75005, France
| | - Caroline Dalle
- Institut Pasteur, Université Paris Cité, Collection of Cyanobacteria, Paris, F-75015, France
| | - Marine Delagrange
- Laboratoire de Physique Statistique, École Normale Supérieure, PSL Research University, Université Paris Diderot Sorbonne Paris-Cité, Sorbonne Université UPMC Paris 06, CNRS, High Throughput qPCR Core Facility of the ENS, IBENS, 46 rue d'Ulm, Paris,, 75005 France
| | - Chakib Djediat
- UMR 7245 Molécules de Communication et Adaptations des Microorganismes (MCAM), Muséum National d'Histoire Naturelle, CNRS, CP 39, 57 rue Cuvier, Paris, 75005, France
| | - Bertrand Ducos
- Laboratoire de Physique Statistique, École Normale Supérieure, PSL Research University, Université Paris Diderot Sorbonne Paris-Cité, Sorbonne Université UPMC Paris 06, CNRS, High Throughput qPCR Core Facility of the ENS, IBENS, 46 rue d'Ulm, Paris,, 75005 France
| | - Charlotte Duval
- UMR 7245 Molécules de Communication et Adaptations des Microorganismes (MCAM), Muséum National d'Histoire Naturelle, CNRS, CP 39, 57 rue Cuvier, Paris, 75005, France
| | - Kathleen Feilke
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Université Paris-Sud, Université Paris-Saclay, Gif sur Yvette, 91198, France
| | - Sahima Hamlaoui
- UMR 7245 Molécules de Communication et Adaptations des Microorganismes (MCAM), Muséum National d'Histoire Naturelle, CNRS, CP 39, 57 rue Cuvier, Paris, 75005, France
| | - Séverine Le Manach
- UMR 7245 Molécules de Communication et Adaptations des Microorganismes (MCAM), Muséum National d'Histoire Naturelle, CNRS, CP 39, 57 rue Cuvier, Paris, 75005, France
| | - Pierre Setif
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Université Paris-Sud, Université Paris-Saclay, Gif sur Yvette, 91198, France
| | - Claude Yéprémian
- UMR 7245 Molécules de Communication et Adaptations des Microorganismes (MCAM), Muséum National d'Histoire Naturelle, CNRS, CP 39, 57 rue Cuvier, Paris, 75005, France
| | - Benjamin Marie
- UMR 7245 Molécules de Communication et Adaptations des Microorganismes (MCAM), Muséum National d'Histoire Naturelle, CNRS, CP 39, 57 rue Cuvier, Paris, 75005, France
| | - Diana Kirilovsky
- Institute for Integrative Biology of the Cell (I2BC), CNRS, CEA, Université Paris-Sud, Université Paris-Saclay, Gif sur Yvette, 91198, France
| | - Muriel Gugger
- Institut Pasteur, Université Paris Cité, Collection of Cyanobacteria, Paris, F-75015, France.
| | - Cécile Bernard
- UMR 7245 Molécules de Communication et Adaptations des Microorganismes (MCAM), Muséum National d'Histoire Naturelle, CNRS, CP 39, 57 rue Cuvier, Paris, 75005, France.
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Kim Tiam S, Comte K, Dalle C, Duval C, Pancrace C, Gugger M, Marie B, Yéprémian C, Bernard C. Development of a new extraction method based on high-intensity ultra-sonication to study RNA regulation of the filamentous cyanobacteria Planktothrix. PLoS One 2019; 14:e0222029. [PMID: 31490972 PMCID: PMC6730872 DOI: 10.1371/journal.pone.0222029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 08/20/2019] [Indexed: 11/24/2022] Open
Abstract
Efficient RNA extraction methods are needed to study transcript regulation. Such methods must lyse the cell without degrading the genetic material. For cyanobacteria this can be particularly challenging because of the presence of the cyanobacteria cell envelope. The great breath of cyanobacterial shape and size (unicellular, colonial, or filamentous multicellular) created a variety of cell lysis methods. However, there is still a lack of reliable techniques for nucleic acid extraction for several types of cyanobacteria. Here we designed and tested 15 extraction methods using physical, thermic or chemical stress on the filamentous cyanobacteria Planktothrix agardhii. Techniques based on the use of beads, sonication, and heat shock appeared to be too soft to break the Planktothrix agardhii cell envelope, whereas techniques based on the use of detergents degraded the cell envelope but also the RNA. Two protocols allowed to successfully obtain good-quality RNA. The first protocol consisted to manually crush the frozen cell pellet with a pestle and the second was based on the use of high-intensity ultra-sonication. When comparing these two, the high-intensity ultra-sonication protocol was less laborious, faster and allowed to extract 3.5 times more RNA compared to the liquid nitrogen pestle protocol. The high-intensity ultra-sonication protocol was then tested on five Planktothrix strains, this protocol allowed to obtain >8.5 μg of RNA for approximatively 3.5 × 108 cells. The extracted RNA were characterized by 260/280 and 260/230 ratio > to 2, indicating that the samples were devoid of contaminant, and RNA Quality Number > to 7, meaning that the integrity of RNA was preserved with this extraction method. In conclusion, the method we developed based on high-intensity ultra-sonication proved its efficacy in the extraction of Planktothrix RNA and could be helpful for other types of samples.
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Affiliation(s)
- Sandra Kim Tiam
- UMR 7245 Molécules de Communication et Adaptations des Microorganismes, Muséum National d’Histoire Naturelle, Paris, France
- * E-mail: (SKT); (CB)
| | - Katia Comte
- UMR 7245 Molécules de Communication et Adaptations des Microorganismes, Muséum National d’Histoire Naturelle, Paris, France
| | - Caroline Dalle
- Collection des Cyanobactéries, Institut Pasteur, Paris, France
| | - Charlotte Duval
- UMR 7245 Molécules de Communication et Adaptations des Microorganismes, Muséum National d’Histoire Naturelle, Paris, France
| | - Claire Pancrace
- Collection des Cyanobactéries, Institut Pasteur, Paris, France
| | - Muriel Gugger
- Collection des Cyanobactéries, Institut Pasteur, Paris, France
| | - Benjamin Marie
- UMR 7245 Molécules de Communication et Adaptations des Microorganismes, Muséum National d’Histoire Naturelle, Paris, France
| | - Claude Yéprémian
- UMR 7245 Molécules de Communication et Adaptations des Microorganismes, Muséum National d’Histoire Naturelle, Paris, France
| | - Cécile Bernard
- UMR 7245 Molécules de Communication et Adaptations des Microorganismes, Muséum National d’Histoire Naturelle, Paris, France
- * E-mail: (SKT); (CB)
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Transcriptomic Responses in the Bloom-Forming Cyanobacterium Microcystis Induced during Exposure to Zooplankton. Appl Environ Microbiol 2017; 83:AEM.02832-16. [PMID: 28003198 PMCID: PMC5311399 DOI: 10.1128/aem.02832-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 12/12/2016] [Indexed: 11/29/2022] Open
Abstract
The bloom-forming, toxic cyanobacterium Microcystis synthesizes multiple secondary metabolites and has been shown to deter zooplankton grazing. However, the biochemical and/or molecular basis by which Microcystis deters zooplankton remains unclear. This global transcriptomic study explored the response of Microcystis to direct and indirect exposures to multiple densities of two cladoceran grazers, Daphnia pulex and D. magna. Higher densities of both daphnids significantly reduced Microcystis cell densities and elicited a stronger transcriptional response in Microcystis. While many putative grazer deterrence genes (encoding microcystin, aeruginosin, cyanopeptolin, and microviridin) were largely unaffected by zooplankton, transcripts for heat shock proteins (hsp) increased in abundance. Beyond metabolites and hsp, large increases in the abundances of transcripts from photosynthetic processes were observed, evidencing energy acquisition pathways were stimulated by grazing. In addition, transcripts of genes associated with the production of extracellular polysaccharides and gas vesicles significantly increased in abundance. These genes have been associated with colony formation and may have been invoked to deter grazers. Collectively, this study demonstrates that daphnid grazers induce a significant transcriptomic response in Microcystis, suggesting this cyanobacterium upregulates specific biochemical pathways to adapt to predation. IMPORTANCE This work explores the transcriptomic responses of Microcystis aeruginosa following exposure to grazing by two cladocerans, Daphnia magna and D. pulex. Contrary to previous hypotheses, Microcystis did not employ putative grazing deterrent secondary metabolites in response to the cladocerans, suggesting they may have other roles within the cell, such as oxidative stress protection. The transcriptional metabolic signature during intense grazing was largely reflective of a growth and stress response, although increasing abundances of transcripts encoding extracellular polysaccharides and gas vesicles were potentially related to predator avoidance.
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Scherer PI, Raeder U, Geist J, Zwirglmaier K. Influence of temperature, mixing, and addition of microcystin-LR on microcystin gene expression in Microcystis aeruginosa. Microbiologyopen 2017; 6:e00393. [PMID: 27411372 PMCID: PMC5300888 DOI: 10.1002/mbo3.393] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 06/22/2016] [Accepted: 06/23/2016] [Indexed: 01/01/2023] Open
Abstract
Cyanobacteria, such as the toxin producer Microcystis aeruginosa, are predicted to be favored by global warming both directly, through elevated water temperatures, and indirectly, through factors such as prolonged stratification of waterbodies. M. aeruginosa is able to produce the hepatotoxin microcystin, which causes great concern in freshwater management worldwide. However, little is known about the expression of microcystin synthesis genes in response to climate change-related factors. In this study, a new RT-qPCR assay employing four reference genes (GAPDH, gltA, rpoC1, and rpoD) was developed to assess the expression of two target genes (the microcystin synthesis genes mcyB and mcyD). This assay was used to investigate changes in mcyB and mcyD expression in response to selected environmental factors associated with global warming. A 10°C rise in temperature significantly increased mcyB expression, but not mcyD expression. Neither mixing nor the addition of microcystin-LR (10 μg L-1 or 60 μg L-1 ) significantly altered mcyB and mcyD expression. The expression levels of mcyB and mcyD were correlated but not identical.
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Affiliation(s)
- Pia I. Scherer
- Aquatic Systems Biology UnitLimnological Research Station IffeldorfDepartment of Ecology and Ecosystem ManagementTechnical University of MunichMunichGermany
| | - Uta Raeder
- Aquatic Systems Biology UnitLimnological Research Station IffeldorfDepartment of Ecology and Ecosystem ManagementTechnical University of MunichMunichGermany
| | - Juergen Geist
- Aquatic Systems Biology UnitLimnological Research Station IffeldorfDepartment of Ecology and Ecosystem ManagementTechnical University of MunichMunichGermany
| | - Katrin Zwirglmaier
- Aquatic Systems Biology UnitLimnological Research Station IffeldorfDepartment of Ecology and Ecosystem ManagementTechnical University of MunichMunichGermany
- Present address: Bundeswehr Institute of MicrobiologyMunichGermany
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