1
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Hiyoshi T, Haga M, Sato N. Preferential phosphatidylglycerol synthesis via phosphorus supply through rRNA degradation in the cyanobacterium, Synechocystis sp. PCC 6803, under phosphate-starved conditions. FRONTIERS IN PLANT SCIENCE 2024; 15:1335085. [PMID: 38348270 PMCID: PMC10859501 DOI: 10.3389/fpls.2024.1335085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 01/08/2024] [Indexed: 02/15/2024]
Abstract
Photosynthetic organisms often encounter phosphorus (P) limitation in natural habitats. When faced with P limitation, seed plants degrade nucleic acids and extra-plastid phospholipids to remobilize P, thereby enhancing their internal-P utilization efficiency. Although prokaryotic and eukaryotic photosynthetic organisms decrease the content of phosphatidylglycerol (PG) under P-limited conditions, it remains unclear whether PG is degraded for P remobilization. Moreover, information is limited on internal-P remobilization in photosynthetic microbes. This study investigates internal-P remobilization under P-starvation (-P) conditions in a cyanobacterium, Synechocystis sp. PCC 6803, focusing on PG and nucleic acids. Our results reveal that the PG content increases by more than double in the -P culture, indicating preferential PG synthesis among cellular P compounds. Simultaneously, the faster increases of glycolipids counteract this PG increase, which decreases the PG proportion in total lipids. Two genes, glpD and plsX, contribute to the synthesis of diacylglycerol moieties in glycerolipids, with glpD also responsible for the polar head group synthesis in PG. The mRNA levels of both glpD and plsX are upregulated during -P, which would cause the preferential metabolic flow of their P-containing substrates toward glycerolipid synthesis, particularly PG synthesis. Meanwhile, we find that RNA accounts for 62% of cellular P, and that rRNA species, which makes up the majority of RNA, are degraded under -P conditions to less than 30% of their initial levels. These findings emphasize the importance of PG in -P-acclimating cell growth and the role of rRNA as a significant internal-P source for P remobilization, including preferential PG synthesis.
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Affiliation(s)
| | | | - Norihiro Sato
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Japan
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2
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Brück P, Wasser D, Soppa J. One Advantage of Being Polyploid: Prokaryotes of Various Phylogenetic Groups Can Grow in the Absence of an Environmental Phosphate Source at the Expense of Their High Genome Copy Numbers. Microorganisms 2023; 11:2267. [PMID: 37764113 PMCID: PMC10536925 DOI: 10.3390/microorganisms11092267] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 08/30/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
Genomic DNA has high phosphate content; therefore, monoploid prokaryotes need an external phosphate source or an internal phosphate storage polymer for replication and cell division. For two polyploid prokaryotic species, the halophilic archaeon Haloferax volcanii and the cyanobacterium Synechocystis PCC 6803, it has been reported that they can grow in the absence of an external phosphate source by reducing the genome copy number per cell. To unravel whether this feature might be widespread in and typical for polyploid prokaryotes, three additional polyploid prokaryotic species were analyzed in the present study, i.e., the alphaproteobacterium Zymomonas mobilis, the gammaproteobacterium Azotobacter vinelandii, and the haloarchaeon Halobacterium salinarum. Polyploid cultures were incubated in the presence and in the absence of external phosphate, growth was recorded, and genome copy numbers per cell were quantified. Limited growth in the absence of phosphate was observed for all three species. Phosphate was added to phosphate-starved cultures to verify that the cells were still viable and growth-competent. Remarkably, stationary-phase cells grown in the absence or presence of phosphate did not become monoploid but stayed oligoploid with about five genome copies per cell. As a negative control, it was shown that monoploid Escherichia coli cultures did not exhibit any growth in the absence of phosphate. Taken together, all five polyploid prokaryotic species that have been characterized until now can grow in the absence of environmental phosphate by reducing their genome copy numbers, indicating that cell proliferation outperforms other evolutionary advantages of polyploidy.
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Affiliation(s)
| | | | - Jörg Soppa
- Biocentre, Institute for Molecular Biosciences, Goethe University, Max-von-Laue-Str. 9, D-60438 Frankfurt, Germany (D.W.)
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3
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Ionescu D, Volland JM, Contarini PE, Gros O. Genomic Mysteries of Giant Bacteria: Insights and Implications. Genome Biol Evol 2023; 15:evad163. [PMID: 37708391 PMCID: PMC10519445 DOI: 10.1093/gbe/evad163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 08/18/2023] [Accepted: 09/01/2023] [Indexed: 09/16/2023] Open
Abstract
Bacteria and Archaea are traditionally regarded as organisms with a simple morphology constrained to a size of 2-3 µm. Nevertheless, the history of microbial research is rich in the description of giant bacteria exceeding tens and even hundreds of micrometers in length or diameter already from its early days, for example, Beggiatoa spp., to the present, for example, Candidatus Thiomargarita magnifica. While some of these giants are still being studied, some were lost to science, with merely drawings and photomicrographs as evidence for their existence. The physiology and biogeochemical role of giant bacteria have been studied, with a large focus on those involved in the sulfur cycle. With the onset of the genomic era, no special emphasis has been given to this group, in an attempt to gain a novel, evolutionary, and molecular understanding of the phenomenon of bacterial gigantism. The few existing genomic studies reveal a mysterious world of hyperpolyploid bacteria with hundreds to hundreds of thousands of chromosomes that are, in some cases, identical and in others, extremely different. These studies on giant bacteria reveal novel organelles, cellular compartmentalization, and novel mechanisms to combat the accumulation of deleterious mutations in polyploid bacteria. In this perspective paper, we provide a brief overview of what is known about the genomics of giant bacteria and build on that to highlight a few burning questions that await to be addressed.
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Affiliation(s)
- Danny Ionescu
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Neuglobsow, Germany
| | - Jean-Marie Volland
- Laboratory for Research in Complex Systems, Menlo Park, California, USA
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Paul-Emile Contarini
- Laboratory for Research in Complex Systems, Menlo Park, California, USA
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d’Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, Pointe-à-Pitre, France
| | - Olivier Gros
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d’Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, Pointe-à-Pitre, France
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4
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Spät P, Krauspe V, Hess WR, Maček B, Nalpas N. Deep Proteogenomics of a Photosynthetic Cyanobacterium. J Proteome Res 2023; 22:1969-1983. [PMID: 37146978 PMCID: PMC10243305 DOI: 10.1021/acs.jproteome.3c00065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Indexed: 05/07/2023]
Abstract
Cyanobacteria, the evolutionary ancestors of plant chloroplasts, contribute substantially to the Earth's biogeochemical cycles and are of great interest for a sustainable economy. Knowledge of protein expression is the key to understanding cyanobacterial metabolism; however, proteome studies in cyanobacteria are limited and cover only a fraction of the theoretical proteome. Here, we performed a comprehensive proteogenomic analysis of the model cyanobacterium Synechocystis sp. PCC 6803 to characterize the expressed (phospho)proteome, re-annotate known and discover novel open reading frames (ORFs). By mapping extensive shotgun mass spectrometry proteomics data onto a six-frame translation of the Synechocystis genome, we refined the genomic annotation of 64 ORFs, including eight completely novel ORFs. Our study presents the largest reported (phospho)proteome dataset for a unicellular cyanobacterium, covering the expression of about 80% of the theoretical proteome under various cultivation conditions, such as nitrogen or carbon limitation. We report 568 phosphorylated S/T/Y sites that are present on numerous regulatory proteins, including the transcriptional regulators cyAbrB1 and cyAbrB2. We also catalogue the proteins that have never been detected under laboratory conditions and found that a large portion of them is plasmid-encoded. This dataset will serve as a resource, providing dedicated information on growth condition-dependent protein expression and phosphorylation.
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Affiliation(s)
- Philipp Spät
- Quantitative
Proteomics, Interfaculty Institute of Cell Biology, University of Tuebingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Vanessa Krauspe
- Genetics
& Experimental Bioinformatics, Institute of Biology III, University of Freiburg, Schänzlestraße 1, 79104 Freiburg im Breisgau, Germany
| | - Wolfgang R. Hess
- Genetics
& Experimental Bioinformatics, Institute of Biology III, University of Freiburg, Schänzlestraße 1, 79104 Freiburg im Breisgau, Germany
| | - Boris Maček
- Quantitative
Proteomics, Interfaculty Institute of Cell Biology, University of Tuebingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Nicolas Nalpas
- Quantitative
Proteomics, Interfaculty Institute of Cell Biology, University of Tuebingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
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5
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Mathur S, Yadav SK, Yadav K, Bhatt S, Kundu S. A novel single sensor hemoglobin domain from the thermophilic cyanobacteria Thermosynechococcus elongatus BP-1 exhibits higher pH but lower thermal stability compared to globins from mesophilic organisms. Int J Biol Macromol 2023; 240:124471. [PMID: 37076076 DOI: 10.1016/j.ijbiomac.2023.124471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 04/11/2023] [Accepted: 04/12/2023] [Indexed: 04/21/2023]
Abstract
Thermosynechococcus elongatus-BP1 belongs to the class of photoautotrophic cyanobacterial organisms. The presence of chlorophyll a, carotenoids, and phycocyanobilin are the characteristics that categorize T. elongatus as a photosynthetic organism. Here, we report the structural and spectroscopic characteristics of novel hemoglobin (Hb) Synel Hb from T.elongatus, synonymous with Thermosynechococcus vestitus BP-1. The X-ray crystal structure (2.15 Å) of Synel Hb suggests the presence of a globin domain with a pre-A helix similar to the sensor domain (S) family of Hbs. The rich hydrophobic core accommodates heme in a penta-coordinated state and readily binds an extraneous ligand(imidazole). The absorption and circular dichroic spectral analysis of Synel Hb reiteratedthat the heme is in FeIII+ state with a predominantly α-helical structure similar to myoglobin. Synel Hb displays higher resistance to structural perturbations induced via external stresses like pH and guanidium hydrochloride, which is comparable to Synechocystis Hb. However, Synel Hb exhibited lower thermal stability compared to mesophilic hemoglobins. Overall, the data is suggestive of the structural sturdiness of Synel Hb, which probably corroborates its origin in extreme thermophilic conditions. The stable globin provides scope for further investigation and may lead to new insights with scope for engineering stability in hemoglobin-based oxygen carriers.
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Affiliation(s)
- Shruti Mathur
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India; Delhi School of Public Health, Institute of Eminence, University of Delhi, Delhi 110007, India
| | - Sanjeev Kumar Yadav
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | - Kajal Yadav
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | - Shruti Bhatt
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | - Suman Kundu
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India; Delhi School of Public Health, Institute of Eminence, University of Delhi, Delhi 110007, India; Birla Institute of Technology and Science Pilani, K.K.Birla Goa Campus, Goa 403726, India.
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6
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Tay JW, Cameron JC. Asymmetric survival in single-cell lineages of cyanobacteria in response to photodamage. PHOTOSYNTHESIS RESEARCH 2023; 155:289-297. [PMID: 36581718 DOI: 10.1007/s11120-022-00986-9] [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: 07/21/2022] [Accepted: 11/14/2022] [Indexed: 06/17/2023]
Abstract
Oxygenic photosynthesis is driven by the coupled action of the light-dependent pigment-protein complexes, photosystem I and II, located within the internal thylakoid membrane system. However, photosystem II is known to be prone to photooxidative damage. Thus, photosynthetic organisms have evolved a repair cycle to continuously replace the damaged proteins in photosystem II. However, it has remained difficult to deconvolute the damage and repair processes using traditional ensemble approaches. Here, we demonstrate an automated approach using time-lapse fluorescence microscopy and computational image analysis to study the dynamics and effects of photodamage in single cells at subcellular resolution in cyanobacteria. By growing cells in a two-dimensional layer, we avoid shading effects, thereby generating uniform and reproducible growth conditions. Using this platform, we analyzed the growth and physiology of multiple strains simultaneously under defined photoinhibitory conditions stimulated by UV-A light. Our results reveal an asymmetric cellular response to photodamage between sibling cells and the generation of an elusive subcellular structure, here named a 'photoendosome,' derived from the thylakoid which could indicate the presence of a previously unknown photoprotective mechanism. We anticipate these results to be a starting point for further studies to better understand photodamage and repair at the single-cell level.
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Affiliation(s)
- Jian Wei Tay
- BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, CO, 80309, USA
| | - Jeffrey C Cameron
- Department of Biochemistry, University of Colorado, Boulder, CO, 80309, USA.
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO, 80309, USA.
- National Renewable Energy Laboratory, Golden, CO, 80401, USA.
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7
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Satta A, Esquirol L, Ebert BE. Current Metabolic Engineering Strategies for Photosynthetic Bioproduction in Cyanobacteria. Microorganisms 2023; 11:microorganisms11020455. [PMID: 36838420 PMCID: PMC9964548 DOI: 10.3390/microorganisms11020455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 02/04/2023] [Accepted: 02/09/2023] [Indexed: 02/16/2023] Open
Abstract
Cyanobacteria are photosynthetic microorganisms capable of using solar energy to convert CO2 and H2O into O2 and energy-rich organic compounds, thus enabling sustainable production of a wide range of bio-products. More and more strains of cyanobacteria are identified that show great promise as cell platforms for the generation of bioproducts. However, strain development is still required to optimize their biosynthesis and increase titers for industrial applications. This review describes the most well-known, newest and most promising strains available to the community and gives an overview of current cyanobacterial biotechnology and the latest innovative strategies used for engineering cyanobacteria. We summarize advanced synthetic biology tools for modulating gene expression and their use in metabolic pathway engineering to increase the production of value-added compounds, such as terpenoids, fatty acids and sugars, to provide a go-to source for scientists starting research in cyanobacterial metabolic engineering.
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Affiliation(s)
- Alessandro Satta
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
- Department of Biology, University of Padua, 35100 Padua, Italy
| | - Lygie Esquirol
- Centre for Cell Factories and Biopolymers, Griffith Institute for Drug Discovery, Griffith University, Natha, QLD 4111, Australia
| | - Birgitta E. Ebert
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
- Correspondence:
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8
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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] [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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9
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Kaltenbrunner A, Reimann V, Hoffmann UA, Aoyagi T, Sakata M, Nimura-Matsune K, Watanabe S, Steglich C, Wilde A, Hess WR. Regulation of pSYSA defense plasmid copy number in Synechocystis through RNase E and a highly transcribed asRNA. Front Microbiol 2023; 14:1112307. [PMID: 36876071 PMCID: PMC9978351 DOI: 10.3389/fmicb.2023.1112307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 01/23/2023] [Indexed: 02/18/2023] Open
Abstract
Synthetic biology approaches toward the development of cyanobacterial producer strains require the availability of appropriate sets of plasmid vectors. A factor for the industrial usefulness of such strains is their robustness against pathogens, such as bacteriophages infecting cyanobacteria. Therefore, it is of great interest to understand the native plasmid replication systems and the CRISPR-Cas based defense mechanisms already present in cyanobacteria. In the model cyanobacterium Synechocystis sp. PCC 6803, four large and three smaller plasmids exist. The ~100 kb plasmid pSYSA is specialized in defense functions by encoding all three CRISPR-Cas systems and several toxin-antitoxin systems. The expression of genes located on pSYSA depends on the plasmid copy number in the cell. The pSYSA copy number is positively correlated with the expression level of the endoribonuclease E. As molecular basis for this correlation we identified the RNase E-mediated cleavage within the pSYSA-encoded ssr7036 transcript. Together with a cis-encoded abundant antisense RNA (asRNA1), this mechanism resembles the control of ColE1-type plasmid replication by two overlapping RNAs, RNA I and II. In the ColE1 mechanism, two non-coding RNAs interact, supported by the small protein Rop, which is encoded separately. In contrast, in pSYSA the similar-sized protein Ssr7036 is encoded within one of the interacting RNAs and it is this mRNA that likely primes pSYSA replication. Essential for plasmid replication is furthermore the downstream encoded protein Slr7037 featuring primase and helicase domains. Deletion of slr7037 led to the integration of pSYSA into the chromosome or the other large plasmid pSYSX. Moreover, the presence of slr7037 was required for successful replication of a pSYSA-derived vector in another model cyanobacterium, Synechococcus elongatus PCC 7942. Therefore, we annotated the protein encoded by slr7037 as Cyanobacterial Rep protein A1 (CyRepA1). Our findings open new perspectives on the development of shuttle vectors for genetic engineering of cyanobacteria and of modulating the activity of the entire CRISPR-Cas apparatus in Synechocystis sp. PCC 6803.
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Affiliation(s)
- Alena Kaltenbrunner
- Genetics and Experimental Bioinformatics Group, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Viktoria Reimann
- Genetics and Experimental Bioinformatics Group, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Ute A Hoffmann
- Molecular Genetics of Prokaryotes, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Tomohiro Aoyagi
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Minori Sakata
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | | | - Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Claudia Steglich
- Genetics and Experimental Bioinformatics Group, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Annegret Wilde
- Molecular Genetics of Prokaryotes, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Wolfgang R Hess
- Genetics and Experimental Bioinformatics Group, Faculty of Biology, University of Freiburg, Freiburg, Germany
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10
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Cengic I, Cañadas IC, Minton NP, Hudson EP. Inducible CRISPR/Cas9 Allows for Multiplexed and Rapidly Segregated Single-Target Genome Editing in Synechocystis Sp. PCC 6803. ACS Synth Biol 2022; 11:3100-3113. [PMID: 35969224 PMCID: PMC9486961 DOI: 10.1021/acssynbio.2c00375] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Establishing various synthetic biology tools is crucial for the development of cyanobacteria for biotechnology use, especially tools that allow for precise and markerless genome editing in a time-efficient manner. Here, we describe a riboswitch-inducible CRISPR/Cas9 system, contained on a single replicative vector, for the model cyanobacterium Synechocystis sp. PCC 6803. A theophylline-responsive riboswitch allowed tight control of Cas9 expression, which enabled reliable transformation of the CRISPR/Cas9 vector intoSynechocystis. Induction of the CRISPR/Cas9 mediated various types of genomic edits, specifically deletions and insertions of varying size. The editing efficiency varied depending on the target and intended edit; smaller edits performed better, reaching, e.g., 100% for insertion of a FLAG-tag onto rbcL. Importantly, the single-vector CRISPR/Cas9 system mediated multiplexed editing of up to three targets in parallel inSynechocystis. All single-target and several double-target mutants were also fully segregated after the first round of induction. Lastly, a vector curing system based on the nickel-inducible expression of the toxic mazF (from Escherichia coli) was added to the CRISPR/Cas9 vector. This inducible system allowed for curing of the vector in 25-75% of screened colonies, enabling edited mutants to become markerless.
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Affiliation(s)
- Ivana Cengic
- School
of Engineering Sciences in Chemistry, Biotechnology and Health, Science
for Life Laboratory, KTH Royal Institute
of Technology, Stockholm 17121, Sweden
| | - Inés C. Cañadas
- BBSRC/EPSRC
Synthetic Biology Research Centre (SBRC), School of Life Sciences, The University of Nottingham, Nottingham NG7 2RD, U.K.
| | - Nigel P. Minton
- BBSRC/EPSRC
Synthetic Biology Research Centre (SBRC), School of Life Sciences, The University of Nottingham, Nottingham NG7 2RD, U.K.
| | - Elton P. Hudson
- School
of Engineering Sciences in Chemistry, Biotechnology and Health, Science
for Life Laboratory, KTH Royal Institute
of Technology, Stockholm 17121, Sweden,
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11
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Riaz S, Jiang Y, Xiao M, You D, Klepacz-Smółka A, Rasul F, Daroch M. Generation of miniploid cells and improved natural transformation procedure for a model cyanobacterium Synechococcus elongatus PCC 7942. Front Microbiol 2022; 13:959043. [PMID: 35958137 PMCID: PMC9360974 DOI: 10.3389/fmicb.2022.959043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 07/01/2022] [Indexed: 11/13/2022] Open
Abstract
The biotechnologically important and naturally transformable cyanobacterium, Synechococcus elongatus PCC 7942, possesses multiple genome copies irrespective of its growth rate or condition. Hence, segregating mutations across all genome copies typically takes several weeks. In this study, Synechococcus 7942 cultivation on a solid growth medium was optimised using different concentrations of agar, the addition of antioxidants, and overexpression of the catalase gene to facilitate the rapid acquisition of colonies and fully segregated lines. Synechococcus 7942 was grown at different temperatures and nutritional conditions. The miniploid cells were identified using flow cytometry and fluorimetry. The natural transformation was carried out using miniploid cells and validated with PCR and high performance liquid chromatography (HPLC). We identified that 0.35% agar concentration and 200 IU of catalase could improve the growth of Synechococcus 7942 on a solid growth medium. Furthermore, overexpression of a catalase gene enhanced the growth rate and supported diluted culture to grow on a solid medium. Our results reveal that high temperature and phosphate-depleted cells contain the lowest genome copies (2.4 ± 0.3 and 1.9 ± 0.2) and showed the potential to rapidly produce fully segregated mutants. In addition, higher antibiotic concentrations improve the selection of homozygous transformants while maintaining similar genome copies at a constant temperature. Based on our observation, we have an improved cultivation and natural transformation protocol for Synechococcus 7942 by optimising solid media culturing, generating low-ploidy cells that ultimately reduced the time required for the complete segregation of engineered lines.
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Affiliation(s)
- Sadaf Riaz
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, United States
| | - Ying Jiang
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Meng Xiao
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Dawei You
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Anna Klepacz-Smółka
- Department of Bioprocess Engineering, Faculty of Process and Environmental Engineering, University of Technology, Łódź, Poland
| | - Faiz Rasul
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Maurycy Daroch
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
- *Correspondence: Maurycy Daroch,
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12
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Mills LA, Moreno-Cabezuelo JÁ, Włodarczyk A, Victoria AJ, Mejías R, Nenninger A, Moxon S, Bombelli P, Selão TT, McCormick AJ, Lea-Smith DJ. Development of a Biotechnology Platform for the Fast-Growing Cyanobacterium Synechococcus sp. PCC 11901. Biomolecules 2022; 12:biom12070872. [PMID: 35883428 PMCID: PMC9313322 DOI: 10.3390/biom12070872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/21/2022] [Accepted: 06/21/2022] [Indexed: 02/07/2023] Open
Abstract
Synechococcus sp. PCC 11901 reportedly demonstrates the highest, most sustained growth of any known cyanobacterium under optimized conditions. Due to its recent discovery, our knowledge of its biology, including the factors underlying sustained, fast growth, is limited. Furthermore, tools specific for genetic manipulation of PCC 11901 are not established. Here, we demonstrate that PCC 11901 shows faster growth than other model cyanobacteria, including the fast-growing species Synechococcuselongatus UTEX 2973, under optimal growth conditions for UTEX 2973. Comparative genomics between PCC 11901 and Synechocystis sp. PCC 6803 reveal conservation of most metabolic pathways but PCC 11901 has a simplified electron transport chain and reduced light harvesting complex. This may underlie its superior light use, reduced photoinhibition, and higher photosynthetic and respiratory rates. To aid biotechnology applications, we developed a vitamin B12 auxotrophic mutant but were unable to generate unmarked knockouts using two negative selectable markers, suggesting that recombinase- or CRISPR-based approaches may be required for repeated genetic manipulation. Overall, this study establishes PCC 11901 as one of the most promising species currently available for cyanobacterial biotechnology and provides a useful set of bioinformatics tools and strains for advancing this field, in addition to insights into the factors underlying its fast growth phenotype.
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Affiliation(s)
- Lauren A. Mills
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK; (L.A.M.); (J.Á.M.-C.); (R.M.); (S.M.)
| | - José Ángel Moreno-Cabezuelo
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK; (L.A.M.); (J.Á.M.-C.); (R.M.); (S.M.)
| | - Artur Włodarczyk
- Bondi Bio Pty Ltd., c/o Climate Change Cluster, University of Technology Sydney, 745 Harris Street, Ultimo, NSW 2007, Australia;
| | - Angelo J. Victoria
- SynthSys and Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK; (A.J.V.); (A.N.); (A.J.M.)
| | - Rebeca Mejías
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK; (L.A.M.); (J.Á.M.-C.); (R.M.); (S.M.)
| | - Anja Nenninger
- SynthSys and Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK; (A.J.V.); (A.N.); (A.J.M.)
| | - Simon Moxon
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK; (L.A.M.); (J.Á.M.-C.); (R.M.); (S.M.)
| | - Paolo Bombelli
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK;
| | - Tiago T. Selão
- Department of Chemical and Environmental Engineering, University of Nottingham, Nottingham NG7 2RD, UK;
| | - Alistair J. McCormick
- SynthSys and Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK; (A.J.V.); (A.N.); (A.J.M.)
| | - David J. Lea-Smith
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK; (L.A.M.); (J.Á.M.-C.); (R.M.); (S.M.)
- Correspondence:
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13
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Juteršek M, Dolinar M. A chimeric vector for dual use in cyanobacteria and Escherichia coli, tested with cystatin, a nonfluorescent reporter protein. PeerJ 2021; 9:e12199. [PMID: 34760347 PMCID: PMC8571960 DOI: 10.7717/peerj.12199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 09/01/2021] [Indexed: 11/23/2022] Open
Abstract
Background Developing sustainable autotrophic cell factories depends heavily on the availability of robust and well-characterized biological parts. For cyanobacteria, these still lag behind the more advanced E. coli toolkit. In the course of previous protein expression experiments with cyanobacteria, we encountered inconveniences in working with currently available RSF1010-based shuttle plasmids, particularly due to their low biosafety and low yields of recombinant proteins. We also recognized some drawbacks of the commonly used fluorescent reporters, as quantification can be affected by the intrinsic fluorescence of cyanobacteria. To overcome these drawbacks, we envisioned a new chimeric vector and an alternative reporter that could be used in cyanobacterial synthetic biology and tested them in the model cyanobacterium Synechocystis sp. PCC 6803. Methods We designed the pMJc01 shuttle plasmid based on the broad host range RSFmob-I replicon. Standard cloning techniques were used for vector construction following the RFC10 synthetic biology standard. The behavior of pMJC01 was tested with selected regulatory elements in E. coli and Synechocystis sp. PCC 6803 for the biosynthesis of the established GFP reporter and of a new reporter protein, cystatin. Cystatin activity was assayed using papain as a cognate target. Results With the new vector we observed a significantly higher GFP expression in E. coli and Synechocystis sp. PCC 6803 compared to the commonly used RSF1010-based pPMQAK1. Cystatin, a cysteine protease inhibitor, was successfully expressed with the new vector in both E. coli and Synechocystis sp. PCC 6803. Its expression levels allowed quantification comparable to the standardly used fluorescent reporter GFPmut3b. An important advantage of the new vector is its improved biosafety due to the absence of plasmid regions encoding conjugative transfer components. The broadhost range vector pMJc01 could find application in synthetic biology and biotechnology of cyanobacteria due to its relatively small size, stability and ease of use. In addition, cystatin could be a useful reporter in all cell systems that do not contain papain-type proteases and inhibitors, such as cyanobacteria, and provides an alternative to fluorescent reporters or complements them.
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Affiliation(s)
- Mojca Juteršek
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia.,Current Affiliation: National Institute of Biology, Ljubljana, Slovenia
| | - Marko Dolinar
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
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14
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Santos M, Pacheco CC, Yao L, Hudson EP, Tamagnini P. CRISPRi as a Tool to Repress Multiple Copies of Extracellular Polymeric Substances (EPS)-Related Genes in the Cyanobacterium Synechocystis sp. PCC 6803. Life (Basel) 2021; 11:life11111198. [PMID: 34833074 PMCID: PMC8620461 DOI: 10.3390/life11111198] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 10/28/2021] [Accepted: 11/03/2021] [Indexed: 12/03/2022] Open
Abstract
The use of the versatile cyanobacterial extracellular polymeric substances (EPS) for biotechnological/biomedical applications implies an extensive knowledge of their biosynthetic pathways to improve/control polymer production yields and characteristics. The multiple copies of EPS-related genes, scattered throughout cyanobacterial genomes, adds another layer of complexity, making these studies challenging and time-consuming. Usually, this issue would be tackled by generating deletion mutants, a process that in cyanobacteria is also hindered by the polyploidy. Thus, the use of the CRISPRi multiplex system constitutes an efficient approach to addressing this redundancy. Here, three putative Synechocystis sp. PCC 6803 kpsM homologues (slr0977, slr2107, and sll0574) were repressed using this methodology. The characterization of the 3-sgRNA mutant in terms of fitness/growth and total carbohydrates, released and capsular polysaccharides, and its comparison with previously generated single knockout mutants pointed towards Slr0977 being the key KpsM player in Synechocystis EPS production. This work validates CRISPRi as a powerful tool to unravel cyanobacterial complex EPS biosynthetic pathways expediting this type of studies.
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Affiliation(s)
- Marina Santos
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4000-008 Porto, Portugal; (M.S.); (C.C.P.)
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4000-008 Porto, Portugal
- Programa Doutoral em Biologia Molecular e Celular (MCbiology), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, 4000-008 Porto, Portugal
| | - Catarina C. Pacheco
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4000-008 Porto, Portugal; (M.S.); (C.C.P.)
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4000-008 Porto, Portugal
| | - Lun Yao
- Science for Life Laboratory, KTH Royal Institute of Technology, 10004 Stockholm, Sweden; (L.Y.); (E.P.H.)
- Department of Protein Science, KTH Royal Institute of Technology, 10004 Stockholm, Sweden
| | - Elton P. Hudson
- Science for Life Laboratory, KTH Royal Institute of Technology, 10004 Stockholm, Sweden; (L.Y.); (E.P.H.)
- Department of Protein Science, KTH Royal Institute of Technology, 10004 Stockholm, Sweden
| | - Paula Tamagnini
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4000-008 Porto, Portugal; (M.S.); (C.C.P.)
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4000-008 Porto, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4000-008 Porto, Portugal
- Correspondence: ; Tel.: +351-226074957
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Yadav I, Rautela A, Kumar S. Approaches in the photosynthetic production of sustainable fuels by cyanobacteria using tools of synthetic biology. World J Microbiol Biotechnol 2021; 37:201. [PMID: 34664124 DOI: 10.1007/s11274-021-03157-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 09/29/2021] [Indexed: 10/20/2022]
Abstract
Cyanobacteria, photosynthetic prokaryotic microorganisms having a simple genetic composition are the prospective photoautotrophic cell factories for the production of a wide range of biofuel molecules. The simple genetic composition of cyanobacteria allows effortless genetic manipulation which leads to increased research endeavors from the synthetic biology approach. Various unicellular model cyanobacterial strains like Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942 have been successfully engineered for biofuels generation. Improved development of synthetic biology tools, genetic modification methods and advancement in transformation techniques to construct a strain that can contain multiple foreign genes in a single operon have vastly expanded the functions that can be used for engineering photosynthetic cyanobacteria for the generation of various biofuel molecules. In this review, recent advancements and approaches in synthetic biology tools used for cyanobacterial genome editing have been discussed. Apart from this, cyanobacterial productions of various fuel molecules like isoprene, limonene, α-farnesene, squalene, alkanes, butanol, and fatty acids, which can be a substitute for petroleum and fossil fuels in the future, have been elaborated.
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Affiliation(s)
- Indrajeet Yadav
- School of Biochemical Engineering, IIT (BHU) Varanasi, Varanasi, Uttar Pradesh, 221005, India
| | - Akhil Rautela
- School of Biochemical Engineering, IIT (BHU) Varanasi, Varanasi, Uttar Pradesh, 221005, India
| | - Sanjay Kumar
- School of Biochemical Engineering, IIT (BHU) Varanasi, Varanasi, Uttar Pradesh, 221005, India.
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Fuchino K, Wasser D, Soppa J. Genome Copy Number Quantification Revealed That the Ethanologenic Alpha-Proteobacterium Zymomonas mobilis Is Polyploid. Front Microbiol 2021; 12:705895. [PMID: 34408736 PMCID: PMC8365228 DOI: 10.3389/fmicb.2021.705895] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 07/07/2021] [Indexed: 11/20/2022] Open
Abstract
The alpha-proteobacterium Zymomonas mobilis is a promising biofuel producer, based on its native metabolism that efficiently converts sugars to ethanol. Therefore, it has a high potential for industrial-scale biofuel production. Two previous studies suggested that Z. mobilis strain Zm4 might not be monoploid. However, a systematic analysis of the genome copy number is still missing, in spite of the high potential importance of Z. mobilis. To get a deep insight into the ploidy level of Z. mobilis and its regulation, the genome copy numbers of three strains were quantified. The analyses revealed that, during anaerobic growth, the lab strain Zm6, the Zm6 type strain obtained from DSMZ (German Collection of Microorganisms), and the lab strain Zm4, have copy numbers of 18.9, 22.3 and 16.2, respectively, of an origin-adjacent region. The copy numbers of a terminus-adjacent region were somewhat lower with 9.3, 15.8, and 12.9, respectively. The values were similar throughout the growth curves, and they were only slightly downregulated in late stationary phase. During aerobic growth, the copy numbers of the lab strain Zm6 were much higher with around 40 origin-adjacent copies and 17 terminus-adjacent copies. However, the cells were larger during aerobic growth, and the copy numbers per μm3 cell volume were rather similar. Taken together, this first systematic analysis revealed that Z. mobilis is polyploid under regular laboratory growth conditions. The copy number is constant during growth, in contrast to many other polyploid bacteria. This knowledge should be considered in further engineering of the strain for industrial applications.
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Affiliation(s)
- Katsuya Fuchino
- Institute for Molecular Biosciences, Goethe-University, Frankfurt, Germany.,Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Daniel Wasser
- Institute for Molecular Biosciences, Goethe-University, Frankfurt, Germany
| | - Jörg Soppa
- Institute for Molecular Biosciences, Goethe-University, Frankfurt, Germany
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17
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Nagy C, Thiel K, Mulaku E, Mustila H, Tamagnini P, Aro EM, Pacheco CC, Kallio P. Comparison of alternative integration sites in the chromosome and the native plasmids of the cyanobacterium Synechocystis sp. PCC 6803 in respect to expression efficiency and copy number. Microb Cell Fact 2021; 20:130. [PMID: 34246263 PMCID: PMC8272380 DOI: 10.1186/s12934-021-01622-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 06/29/2021] [Indexed: 11/10/2022] Open
Abstract
Background Synechocystis sp. PCC 6803 provides a well-established reference point to cyanobacterial metabolic engineering as part of basic photosynthesis research, as well as in the development of next-generation biotechnological production systems. This study focused on expanding the current knowledge on genomic integration of expression constructs in Synechocystis, targeting a range of novel sites in the chromosome and in the native plasmids, together with established loci used in literature. The key objective was to obtain quantitative information on site-specific expression in reference to replicon copy numbers, which has been speculated but never compared side by side in this host. Results An optimized sYFP2 expression cassette was successfully integrated in two novel sites in Synechocystis chromosome (slr0944; sll0058) and in all four endogenous megaplasmids (pSYSM/slr5037-slr5038; pSYSX/slr6037; pSYSA/slr7023; pSYSG/slr8030) that have not been previously evaluated for the purpose. Fluorescent analysis of the segregated strains revealed that the expression levels between the megaplasmids and chromosomal constructs were very similar, and reinforced the view that highest expression in Synechocystis can be obtained using RSF1010-derived replicative vectors or the native small plasmid pCA2.4 evaluated in comparison. Parallel replicon copy number analysis by RT-qPCR showed that the expression from the alternative loci is largely determined by the gene dosage in Synechocystis, thereby confirming the dependence formerly proposed based on literature. Conclusions This study brings together nine different integrative loci in the genome of Synechocystis to demonstrate quantitative differences between target sites in the chromosome, the native plasmids, and a RSF1010-based replicative expression vector. To date, this is the most comprehensive comparison of alternative integrative sites in Synechocystis, and provides the first direct reference between expression efficiency and replicon gene dosage in the context. In the light of existing literature, the findings support the view that the small native plasmids can be notably more difficult to target than the chromosome or the megaplasmids, and that the RSF1010-derived vectors may be surprisingly well maintained under non-selective culture conditions in this cyanobacterial host. Altogether, the work broadens our views on genomic integration and the rational use of different integrative loci versus replicative plasmids, when aiming at expressing heterologous genes in Synechocystis. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-021-01622-2.
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Affiliation(s)
- Csaba Nagy
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Itäinen Pitkäkatu 4 C, 20520, Turku, Finland
| | - Kati Thiel
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Itäinen Pitkäkatu 4 C, 20520, Turku, Finland
| | - Edita Mulaku
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Itäinen Pitkäkatu 4 C, 20520, Turku, Finland
| | - Henna Mustila
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Itäinen Pitkäkatu 4 C, 20520, Turku, Finland
| | - Paula Tamagnini
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal.,IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal.,Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, Edifício FC4, 4169-007, Porto, Portugal
| | - Eva-Mari Aro
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Itäinen Pitkäkatu 4 C, 20520, Turku, Finland
| | - Catarina C Pacheco
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal.,IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal
| | - Pauli Kallio
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Itäinen Pitkäkatu 4 C, 20520, Turku, Finland.
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MacCready JS, Tran L, Basalla JL, Hakim P, Vecchiarelli AG. The McdAB system positions α-carboxysomes in proteobacteria. Mol Microbiol 2021; 116:277-297. [PMID: 33638215 PMCID: PMC8359340 DOI: 10.1111/mmi.14708] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/23/2021] [Accepted: 02/24/2021] [Indexed: 02/06/2023]
Abstract
Carboxysomes are protein-based organelles essential for carbon fixation in cyanobacteria and proteobacteria. Previously, we showed that the cyanobacterial nucleoid is used to equally space out β-carboxysomes across cell lengths by a two-component system (McdAB) in the model cyanobacterium Synechococcus elongatus PCC 7942. More recently, we found that McdAB systems are widespread among β-cyanobacteria, which possess β-carboxysomes, but are absent in α-cyanobacteria, which possess structurally and phyletically distinct α-carboxysomes. Cyanobacterial α-carboxysomes are thought to have arisen in proteobacteria and then horizontally transferred into cyanobacteria, which suggests that α-carboxysomes in proteobacteria may also lack the McdAB system. Here, using the model chemoautotrophic proteobacterium Halothiobacillus neapolitanus, we show that a McdAB system distinct from that of β-cyanobacteria operates to position α-carboxysomes across cell lengths. We further show that this system is widespread among α-carboxysome-containing proteobacteria and that cyanobacteria likely inherited an α-carboxysome operon from a proteobacterium lacking the mcdAB locus. These results demonstrate that McdAB is a cross-phylum two-component system necessary for positioning both α- and β-carboxysomes. The findings have further implications for understanding the positioning of other protein-based bacterial organelles involved in diverse metabolic processes. PLAIN LANGUAGE SUMMARY: Cyanobacteria are well known to fix atmospheric CO2 into sugars using the enzyme Rubisco. Less appreciated are the carbon-fixing abilities of proteobacteria with diverse metabolisms. Bacterial Rubisco is housed within organelles called carboxysomes that increase enzymatic efficiency. Here we show that proteobacterial carboxysomes are distributed in the cell by two proteins, McdA and McdB. McdA on the nucleoid interacts with McdB on carboxysomes to equidistantly space carboxysomes from one another, ensuring metabolic homeostasis and a proper inheritance of carboxysomes following cell division. This study illuminates how widespread carboxysome positioning systems are among diverse bacteria. Carboxysomes significantly contribute to global carbon fixation; therefore, understanding the spatial organization mechanism shared across the bacterial world is of great interest.
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Affiliation(s)
- Joshua S. MacCready
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborMIUSA
| | - Lisa Tran
- Department of Microbiology and ImmunologyUniversity of MichiganAnn ArborMIUSA
| | - Joseph L. Basalla
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborMIUSA
| | - Pusparanee Hakim
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborMIUSA
| | - Anthony G. Vecchiarelli
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborMIUSA
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Choi YN, Shin YR, Park JM, Lee JW. Cell-Free Transcription-Coupled CRISPR/Cas12a Assay for Prototyping Cyanobacterial Promoters. ACS Synth Biol 2021; 10:1300-1307. [PMID: 34015913 DOI: 10.1021/acssynbio.1c00148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cyanobacteria are promising microbial hosts for the production of diverse biofuels and biochemicals. However, compared to other model microbial hosts such as Escherichia coli and yeast, it takes a long time to genetically modify cyanobacteria. One way to efficiently engineer cyanobacteria while minimizing genetic engineering would be to develop a fast, high-throughput prototyping tool for cyanobacteria. In this study, we developed a CRISPR/Cas12a-based assay coupled with cyanobacteria cell-free systems to rapidly prototype promoter characteristics. Using this newly developed assay, we demonstrated cyanobacteria cell-free transcription for the first time and confirmed a positive correlation between the in vitro and in vivo transcription performance. Furthermore, we generated a synthetic promoter library and evaluated the characteristics of promoter subregions by using the assay. Varied promoter strength derived from random mutations were rapidly and effectively measured in a high-throughput way. We believe that this study offers an easily applicable and rapid prototyping platform to characterize promoters for cyanobacterial engineering.
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Affiliation(s)
- Yun-Nam Choi
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Korea
| | - Ye Rim Shin
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Korea
| | - Jong Moon Park
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Korea
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Korea
- School of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Korea
- Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Korea
- School of Integrated Technology, Yonsei University (POSTECH-Yonsei Open Campus), 77 Cheongam-Ro, Nam-Gu, Pohang, Gyungbuk, 37673, Korea
| | - Jeong Wook Lee
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Korea
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Korea
- School of Integrated Technology, Yonsei University (POSTECH-Yonsei Open Campus), 77 Cheongam-Ro, Nam-Gu, Pohang, Gyungbuk, 37673, Korea
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The Genome Copy Number of the Thermophilic Cyanobacterium Thermosynechococcus elongatus E542 Is Controlled by Growth Phase and Nutrient Availability. Appl Environ Microbiol 2021; 87:AEM.02993-20. [PMID: 33608293 PMCID: PMC8091003 DOI: 10.1128/aem.02993-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 02/13/2021] [Indexed: 12/20/2022] Open
Abstract
The present study revealed that the genome copy number (ploidy) status in the thermophilic cyanobacterium Thermosynechococcus E542 is regulated by growth phase and various environmental parameters to give us a window into understanding the role of polyploidy. An increased ploidy level is found to be associated with higher metabolic activity and increased vigor by acting as backup genetic information to compensate for damage to the other chromosomal copies. The recently isolated thermophilic cyanobacterium Thermosynechococcus elongatus PKUAC-SCTE542 (here Thermosynechococcus E542) is a promising strain for fundamental and applied research. Here, we used several improved ploidy estimation approaches, which include quantitative PCR (qPCR), spectrofluorometry, and flow cytometry, to precisely determine the ploidy level in Thermosynechococcus E542 across different growth stages and nutritional and stress conditions. The distribution of genome copies per cell among the populations of Thermosynechococcus E542 was also analyzed. The strain tends to maintain 3 or 4 genome copies per cell in lag phase, early growth phase, or stationary phase under standard conditions. Increased ploidy (5.5 ± 0.3) was observed in exponential phase; hence, the ploidy level is growth phase regulated. Nearly no monoploid cells were detected in all growth phases, and prolonged stationary phase could not yield ploidy levels lower than 3 under standard conditions. During the late growth phase, a significantly higher ploidy level was observed in the presence of bicarbonate (7.6 ± 0.7) and high phosphate (6.9 ± 0.2) at the expense of reduced percentages of di- and triploid cells. Meanwhile, the reduction in phosphates decreased the average ploidy level by increasing the percentages of mono- and diploid cells. In contrast, temperature and antibiotic stresses reduced the percentages of mono-, di-, and triploid cells yet maintained average ploidy. The results indicate a possible causality between growth rate, stress, and genome copy number across the conditions tested, but the exact mechanism is yet to be elucidated. Furthermore, the spectrofluorometric approach presented here is a quick and straightforward ploidy estimation method with reasonable accuracy. IMPORTANCE The present study revealed that the genome copy number (ploidy) status in the thermophilic cyanobacterium Thermosynechococcus E542 is regulated by growth phase and various environmental parameters to give us a window into understanding the role of polyploidy. An increased ploidy level is found to be associated with higher metabolic activity and increased vigor by acting as backup genetic information to compensate for damage to the other chromosomal copies. Several improved ploidy estimation approaches that may upgrade the ploidy estimation procedure for cyanobacteria in the future are presented in this work. Furthermore, the new spectrofluorometric method presented here is a rapid and straightforward method of ploidy estimation with reasonable accuracy compared to other laborious methods.
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21
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Genetic, Genomics, and Responses to Stresses in Cyanobacteria: Biotechnological Implications. Genes (Basel) 2021; 12:genes12040500. [PMID: 33805386 PMCID: PMC8066212 DOI: 10.3390/genes12040500] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/25/2021] [Accepted: 03/25/2021] [Indexed: 02/07/2023] Open
Abstract
Cyanobacteria are widely-diverse, environmentally crucial photosynthetic prokaryotes of great interests for basic and applied science. Work to date has focused mostly on the three non-nitrogen fixing unicellular species Synechocystis PCC 6803, Synechococcus PCC 7942, and Synechococcus PCC 7002, which have been selected for their genetic and physiological interests summarized in this review. Extensive "omics" data sets have been generated, and genome-scale models (GSM) have been developed for the rational engineering of these cyanobacteria for biotechnological purposes. We presently discuss what should be done to improve our understanding of the genotype-phenotype relationships of these models and generate robust and predictive models of their metabolism. Furthermore, we also emphasize that because Synechocystis PCC 6803, Synechococcus PCC 7942, and Synechococcus PCC 7002 represent only a limited part of the wide biodiversity of cyanobacteria, other species distantly related to these three models, should be studied. Finally, we highlight the need to strengthen the communication between academic researchers, who know well cyanobacteria and can engineer them for biotechnological purposes, but have a limited access to large photobioreactors, and industrial partners who attempt to use natural or engineered cyanobacteria to produce interesting chemicals at reasonable costs, but may lack knowledge on cyanobacterial physiology and metabolism.
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Zupančič M, Kogovšek P, Šter T, Remec Rekar Š, Cerasino L, Baebler Š, Krivograd Klemenčič A, Eleršek T. Potentially Toxic Planktic and Benthic Cyanobacteria in Slovenian Freshwater Bodies: Detection by Quantitative PCR. Toxins (Basel) 2021; 13:toxins13020133. [PMID: 33670338 PMCID: PMC7917684 DOI: 10.3390/toxins13020133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/03/2021] [Accepted: 02/09/2021] [Indexed: 11/16/2022] Open
Abstract
Due to increased frequency of cyanobacterial blooms and emerging evidence of cyanotoxicity in biofilm, reliable methods for early cyanotoxin threat detection are of major importance for protection of human, animal and environmental health. To complement the current methods of risk assessment, this study aimed to evaluate selected qPCR assays for detection of potentially toxic cyanobacteria in environmental samples. In the course of one year, 25 plankton and 23 biofilm samples were collected from 15 water bodies in Slovenia. Three different analyses were performed and compared to each other; qPCR targeting mcyE, cyrJ and sxtA genes involved in cyanotoxin production, LC-MS/MS quantifying microcystin, cylindrospermopsin and saxitoxin concentration, and microscopic analyses identifying potentially toxic cyanobacterial taxa. qPCR analyses detected potentially toxic Microcystis in 10 lake plankton samples, and potentially toxic Planktothrix cells in 12 lake plankton and one lake biofilm sample. A positive correlation was observed between numbers of mcyE gene copies and microcystin concentrations. Potential cylindrospermopsin- and saxitoxin-producers were detected in three and seven lake biofilm samples, respectively. The study demonstrated a potential for cyanotoxin production that was left undetected by traditional methods in both plankton and biofilm samples. Thus, the qPCR method could be useful in regular monitoring of water bodies to improve risk assessment and enable timely measures.
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Affiliation(s)
- Maša Zupančič
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, 1000 Ljubljana, Slovenia;
- Jozef Stefan International Postgraduate School, 1000 Ljubljana, Slovenia
- Correspondence:
| | - Polona Kogovšek
- Department of Biotechnology and Systems Biology, National Institute of Biology, 1000 Ljubljana, Slovenia; (P.K.); (Š.B.)
| | - Tadeja Šter
- Slovenian Environment Agency, 1000 Ljubljana, Slovenia; (T.Š.); (Š.R.R.); (A.K.K.)
| | - Špela Remec Rekar
- Slovenian Environment Agency, 1000 Ljubljana, Slovenia; (T.Š.); (Š.R.R.); (A.K.K.)
| | - Leonardo Cerasino
- Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre, Fondazione Edmund Mach, 38010 San Michele all’Adige, Italy;
| | - Špela Baebler
- Department of Biotechnology and Systems Biology, National Institute of Biology, 1000 Ljubljana, Slovenia; (P.K.); (Š.B.)
| | | | - Tina Eleršek
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, 1000 Ljubljana, Slovenia;
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Battaglino B, Arduino A, Pagliano C. Mathematical modeling for the design of evolution experiments to study the genetic instability of metabolically engineered photosynthetic microorganisms. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.102093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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24
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Schirmacher AM, Hanamghar SS, Zedler JAZ. Function and Benefits of Natural Competence in Cyanobacteria: From Ecology to Targeted Manipulation. Life (Basel) 2020; 10:E249. [PMID: 33105681 PMCID: PMC7690421 DOI: 10.3390/life10110249] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 10/18/2020] [Accepted: 10/20/2020] [Indexed: 02/03/2023] Open
Abstract
Natural competence is the ability of a cell to actively take up and incorporate foreign DNA in its own genome. This trait is widespread and ecologically significant within the prokaryotic kingdom. Here we look at natural competence in cyanobacteria, a group of globally distributed oxygenic photosynthetic bacteria. Many cyanobacterial species appear to have the genetic potential to be naturally competent, however, this ability has only been demonstrated in a few species. Reasons for this might be due to a high variety of largely uncharacterised competence inducers and a lack of understanding the ecological context of natural competence in cyanobacteria. To shed light on these questions, we describe what is known about the molecular mechanisms of natural competence in cyanobacteria and analyse how widespread this trait might be based on available genomic datasets. Potential regulators of natural competence and what benefits or drawbacks may derive from taking up foreign DNA are discussed. Overall, many unknowns about natural competence in cyanobacteria remain to be unravelled. A better understanding of underlying mechanisms and how to manipulate these, can aid the implementation of cyanobacteria as sustainable production chassis.
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Affiliation(s)
| | | | - Julie A. Z. Zedler
- Matthias Schleiden Institute for Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, 07743 Jena, Germany; (A.M.S.); (S.S.H.)
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25
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Caicedo-Burbano P, Smit T, Pineda Hernández H, Du W, Branco dos Santos F. Construction of Fully Segregated Genomic Libraries in Polyploid Organisms Such as Synechocystis sp. PCC 6803. ACS Synth Biol 2020; 9:2632-2638. [PMID: 33017143 PMCID: PMC7573980 DOI: 10.1021/acssynbio.0c00353] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Indexed: 12/11/2022]
Abstract
Several microbes are polyploid, meaning they contain several copies of their chromosome. Cyanobacteria, while holding great potential as photosynthetic cell factories of various products, are found among them. In these clades the diversity of genetic elements that serve within the basic molecular toolbox is often limiting. To assist mining for the latter, we present here a method for the generation of fully segregated genomic libraries, specifically designed for polyploids. We provide proof-of-principle for this method by generating a fully segregated genomic promoter library in the cyanobacterium Synechocystis sp. PCC 6803. This new tool was first analyzed through fluorescence activated cell sorting (FACS) and then a fraction was further characterized regarding promoter sequence. The location of libraries on the chromosome provides a better reflection of the behavior of its elements. Our work presents the first method for constructing fully segregated genomic libraries in polyploids, which may facilitate their usage in synthetic biology applications.
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Affiliation(s)
- Patricia Caicedo-Burbano
- Molecular
Microbial Physiology Group, Swammerdam Institute for Life Sciences,
Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH,The Netherlands
| | - Tycho Smit
- Molecular
Microbial Physiology Group, Swammerdam Institute for Life Sciences,
Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH,The Netherlands
| | - Hugo Pineda Hernández
- Molecular
Microbial Physiology Group, Swammerdam Institute for Life Sciences,
Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH,The Netherlands
| | - Wei Du
- Molecular
Microbial Physiology Group, Swammerdam Institute for Life Sciences,
Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH,The Netherlands
| | - Filipe Branco dos Santos
- Molecular
Microbial Physiology Group, Swammerdam Institute for Life Sciences,
Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH,The Netherlands
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26
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Nies F, Mielke M, Pochert J, Lamparter T. Natural transformation of the filamentous cyanobacterium Phormidium lacuna. PLoS One 2020; 15:e0234440. [PMID: 32530971 PMCID: PMC7292380 DOI: 10.1371/journal.pone.0234440] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 05/25/2020] [Indexed: 02/06/2023] Open
Abstract
Research for biotechnological applications of cyanobacteria focuses on synthetic pathways and bioreactor design, while little effort is devoted to introduce new, promising organisms in the field. Applications are most often based on recombinant work, and the establishment of transformation can be a risky, time-consuming procedure. In this work we demonstrate the natural transformation of the filamentous cyanobacterium Phormidium lacuna and insertion of a selection marker into the genome by homologous recombination. This is the first example for natural transformation filamentous non-heterocystous cyanobacterium. We found that Phormidium lacuna is polyploid, each cell has about 20-90 chromosomes. Transformed filaments were resistant against up to 14 mg/ml of kanamycin. Formerly, natural transformation in cyanobacteria has been considered a rare and exclusive feature of a few unicellular species. Our finding suggests that natural competence is more distributed among cyanobacteria than previously thought. This is supported by bioinformatic analyses which show that all protein factors for natural transformation are present in the majority of the analyzed cyanobacteria.
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Affiliation(s)
- Fabian Nies
- Botanical Institute, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Marion Mielke
- Botanical Institute, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Janko Pochert
- Botanical Institute, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Tilman Lamparter
- Botanical Institute, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
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27
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Cavaiuolo M, Chagneau C, Laalami S, Putzer H. Impact of RNase E and RNase J on Global mRNA Metabolism in the Cyanobacterium Synechocystis PCC6803. Front Microbiol 2020; 11:1055. [PMID: 32582060 PMCID: PMC7283877 DOI: 10.3389/fmicb.2020.01055] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 04/29/2020] [Indexed: 01/18/2023] Open
Abstract
mRNA levels result from an equilibrium between transcription and degradation. Ribonucleases (RNases) facilitate the turnover of mRNA, which is an important way of controlling gene expression, allowing the cells to adjust transcript levels to a changing environment. In contrast to the heterotrophic model bacteria Escherichia coli and Bacillus subtilis, RNA decay has not been studied in detail in cyanobacteria. Synechocystis sp. PCC6803 encodes orthologs of both E. coli and B. subtilis RNases, including RNase E and RNase J, respectively. We show that in vitro Sy RNases E and J have an endonucleolytic cleavage specificity that is very similar between them and also compared to orthologous enzymes from E. coli, B. subtilis, and Chlamydomonas. Moreover, Sy RNase J displays a robust 5′-exoribonuclease activity similar to B. subtilis RNase J1, but unlike the evolutionarily related RNase J in chloroplasts. Both nucleases are essential and gene deletions could not be fully segregated in Synechocystis. We generated partially disrupted strains of Sy RNase E and J that were stable enough to allow for their growth and characterization. A transcriptome analysis of these strains partially depleted for RNases E and J, respectively, allowed to observe effects on specific transcripts. RNase E altered the expression of a larger number of chromosomal genes and antisense RNAs compared to RNase J, which rather affects endogenous plasmid encoded transcripts. Our results provide the first description of the main transcriptomic changes induced by the partial depletion of two essential ribonucleases in cyanobacteria.
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Affiliation(s)
- Marina Cavaiuolo
- UMR 8261, CNRS, Institut de Biologie Physico-Chimique, Université de Paris, Paris, France
| | - Carine Chagneau
- UMR 8261, CNRS, Institut de Biologie Physico-Chimique, Université de Paris, Paris, France
| | - Soumaya Laalami
- UMR 8261, CNRS, Institut de Biologie Physico-Chimique, Université de Paris, Paris, France
| | - Harald Putzer
- UMR 8261, CNRS, Institut de Biologie Physico-Chimique, Université de Paris, Paris, France
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28
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Ohbayashi R, Hirooka S, Onuma R, Kanesaki Y, Hirose Y, Kobayashi Y, Fujiwara T, Furusawa C, Miyagishima SY. Evolutionary Changes in DnaA-Dependent Chromosomal Replication in Cyanobacteria. Front Microbiol 2020; 11:786. [PMID: 32411117 PMCID: PMC7198777 DOI: 10.3389/fmicb.2020.00786] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/02/2020] [Indexed: 12/02/2022] Open
Abstract
Replication of the circular bacterial chromosome is initiated at a unique origin (oriC) in a DnaA-dependent manner in which replication proceeds bidirectionally from oriC to ter. The nucleotide compositions of most bacteria differ between the leading and lagging DNA strands. Thus, the chromosomal DNA sequence typically exhibits an asymmetric GC skew profile. Further, free-living bacteria without genomes encoding dnaA were unknown. Thus, a DnaA-oriC-dependent replication initiation mechanism may be essential for most bacteria. However, most cyanobacterial genomes exhibit irregular GC skew profiles. We previously found that the Synechococcus elongatus chromosome, which exhibits a regular GC skew profile, is replicated in a DnaA-oriC-dependent manner, whereas chromosomes of Synechocystis sp. PCC 6803 and Nostoc sp. PCC 7120, which exhibit an irregular GC skew profile, are replicated from multiple origins in a DnaA-independent manner. Here we investigate the variation in the mechanisms of cyanobacterial chromosome replication. We found that the genomes of certain free-living species do not encode dnaA and such species, including Cyanobacterium aponinum PCC 10605 and Geminocystis sp. NIES-3708, replicate their chromosomes from multiple origins. Synechococcus sp. PCC 7002, which is phylogenetically closely related to dnaA-lacking free-living species as well as to dnaA-encoding but DnaA-oriC-independent Synechocystis sp. PCC 6803, possesses dnaA. In Synechococcus sp. PCC 7002, dnaA was not essential and its chromosomes were replicated from a unique origin in a DnaA-oriC independent manner. Our results also suggest that loss of DnaA-oriC-dependency independently occurred multiple times during cyanobacterial evolution and raises a possibility that the loss of dnaA or loss of DnaA-oriC dependency correlated with an increase in ploidy level.
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Affiliation(s)
- Ryudo Ohbayashi
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan
| | - Shunsuke Hirooka
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan
| | - Ryo Onuma
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan
| | - Yu Kanesaki
- Research Institute of Green Science and Technology, Shizuoka University, Shizuoka, Japan
| | - Yuu Hirose
- Department of Applied Chemistry and Life Science, Toyohashi University of Technology, Toyohashi, Japan
| | - Yusuke Kobayashi
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan
| | - Takayuki Fujiwara
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan.,Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Shizuoka, Japan
| | - Chikara Furusawa
- Center for Biosystems Dynamics Research, RIKEN, Osaka, Japan.,Universal Biology Institute, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Shin-Ya Miyagishima
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan.,Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Shizuoka, Japan
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29
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Combining Random Mutagenesis and Metabolic Engineering for Enhanced Tryptophan Production in Synechocystis sp. Strain PCC 6803. Appl Environ Microbiol 2020; 86:AEM.02816-19. [PMID: 32144109 DOI: 10.1128/aem.02816-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 02/27/2020] [Indexed: 01/08/2023] Open
Abstract
Tryptophan (Trp) is an essential aromatic amino acid that has value as an animal feed supplement, as the amount found in plant-based sources is insufficient. An alternative to production by engineered microbial fermentation is to have tryptophan biosynthesized by a photosynthetic microorganism that could replace or supplement both the plant and industrially used microbes. We selected Synechocystis sp. strain PCC 6803, a model cyanobacterium, as the host and studied metabolic engineering and random mutagenesis approaches. Previous work on engineering heterotrophic microbes for improved Trp titers has targeted allosteric feedback regulation in enzymes 3-deoxy-d-arabinoheptulosonate 7-phosphate synthase (DAHPS) and anthranilate synthase (AS) as major bottlenecks in the shikimate pathway. In this work, the genes encoding feedback-resistant enzymes from Escherichia coli, aroGfbr and trpEfbr , were overexpressed in the host wild-type (WT) strain. Separately, the WT strain was subjected to random mutagenesis and selection using an amino acid analog to isolate tryptophan-overproducing strains. The randomly mutagenized strains were sequenced in order to identify the mutations that resulted in the desirable phenotypes. Interestingly, the tryptophan overproducers had mutations in the gene encoding chorismate mutase (CM), which catalyzes the conversion of chorismate to prephenate. The best tryptophan overproducer from random mutagenesis was selected as a host for metabolic engineering where aroGfbr and trpEfbr were overexpressed. The best strain developed produced 212 ± 23 mg/liter of tryptophan after 10 days of photoautotrophic growth under 3% (vol/vol) CO2 We demonstrated that a combination of random mutagenesis and metabolic engineering was superior to either individual approach.IMPORTANCE Aromatic amino acids such as tryptophan are primarily used as additives in the animal feed industry and are typically produced using genetically engineered heterotrophic organisms such as Escherichia coli This involves a two-step process, where the substrate such as molasses is first obtained from plants followed by fermentation by heterotrophic organisms. We have engineered photoautotrophic cyanobacterial strains by a combination of random mutagenesis and metabolic engineering. These strains grow on CO2 as the sole carbon source and utilize light as the sole energy source to produce tryptophan, thus converting the two-step process into a single step. Our results show that combining random mutagenesis and metabolic engineering was superior to either approach alone. This study also builds a foundation for further engineering of cyanobacteria for industrial tryptophan production.
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Pope MA, Hodge JA, Nixon PJ. An Improved Natural Transformation Protocol for the Cyanobacterium Synechocystis sp. PCC 6803. FRONTIERS IN PLANT SCIENCE 2020; 11:372. [PMID: 32351517 PMCID: PMC7174562 DOI: 10.3389/fpls.2020.00372] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 03/16/2020] [Indexed: 06/11/2023]
Abstract
The naturally transformable cyanobacterium Synechocystis sp. PCC 6803 is a widely used chassis strain for the photosynthetic production of chemicals. However, Synechocystis possesses multiple genome copies per cell which means that segregating mutations across all genome copies can be time-consuming. Here we use flow cytometry in combination with DNA staining to investigate the effect of phosphate deprivation on the genome copy number of the glucose-tolerant GT-P sub-strain of Synechocystis 6803. Like the PCC 6803 wild type strain, the ploidy of GT-P cells grown in BG-11 medium is growth phase dependent with an average genome copy number of 6.05 ± 0.27 in early growth (OD740 = 0.1) decreasing to 2.49 ± 0.11 in late stationary phase (OD740 = 7). We show that a 10-fold reduction in the initial phosphate concentration of the BG-11 growth medium reduces the average genome copy number of GT-P cells from 4.51 ± 0.20 to 2.94 ± 0.13 and increases the proportion of monoploid cells from 0 to 6% after 7 days of growth. In addition, we also show that the DnaA protein, which unusually for bacteria is not required for DNA replication in Synechocystis, plays a role in restoring polyploidy upon subsequent phosphate supplementation. Based on these observations, we have developed an alternative natural transformation protocol involving phosphate depletion that decreases the time required to obtain fully segregated mutants.
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Valev D, Kurkela J, Tyystjärvi E, Tyystjärvi T. Testing the Potential of Regulatory Sigma Factor Mutants for Wastewater Purification or Bioreactor Run in High Light. Curr Microbiol 2020; 77:1590-1599. [PMID: 32266454 PMCID: PMC7334282 DOI: 10.1007/s00284-020-01973-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Accepted: 03/27/2020] [Indexed: 11/25/2022]
Abstract
It is shown that a freshly inoculated culture of the model cyanobacterium Synechocystis sp. PCC 6803 consumed almost all phosphate and 50% of nitrate within 6 days from the nutrient-rich BG-11 growth medium, indicating potential of cyanobacteria to purify wastewaters. Synechocystis sp. PCC 6803 control strain also collected nutrients efficiently from a landfill leachate wastewater KA2 (5.9-6.9 mM ammonium and 0.073-0.077 mM phosphate). Wastewaters might induce oxidative stress to microalgae, which prompted us to test growth of sigma factor inactivation strains, as ΔsigBCE and ΔsigCDE strains show superior growth in chemically induced oxidative stress. All cyanobacterial strains, including a stress-sensitive strain ΔsigBCDE, grew well in KA2 for four days, indicating that KA2 did not cause immediate oxidative stress. Completely arrested growth and bleaching of ΔsigBCDE cells after one week in KA2 wastewater point to the importance of group 2 sigma factor-mediated changes in gene expression during wastewater treatment. The growth of ΔsigBCD was arrested early in un-buffered and Hepes buffered (pH 7.5) KA2. In ΔsigBCD, all phosphate transporter genes are upregulated in standard conditions, and ΔsigBCD cells showed growth defects in low-phosphate BG-11 medium. ΔsigBCD cells removed phosphate slower from KA2 than the control strain, but phosphate supplementation of KA2 did not improve growth of ΔsigBCD. The ΔsigBCE strain showed superior growth in a laboratory-scale bioreactor in bright light and removed phosphate even slightly more efficiently than the control strain if KA2 was Hepes buffered although ΔsigBCE grew slowly in un-buffered KA2 and in low-phosphate BG-11 medium. The results indicate that engineering expression of regulatory group 2 sigma factor(s) might be useful for practical applications.
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Affiliation(s)
- Dimitar Valev
- Department of Biochemistry/Molecular Plant Biology, University of Turku, 20014, Turku, Finland
| | - Juha Kurkela
- Department of Biochemistry/Molecular Plant Biology, University of Turku, 20014, Turku, Finland
| | - Esa Tyystjärvi
- Department of Biochemistry/Molecular Plant Biology, University of Turku, 20014, Turku, Finland
| | - Taina Tyystjärvi
- Department of Biochemistry/Molecular Plant Biology, University of Turku, 20014, Turku, Finland.
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32
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Abstract
While the model bacteria Escherichia coli and Bacillus subtilis harbor single chromosomes, which is known as monoploidy, some freshwater cyanobacteria contain multiple chromosome copies per cell throughout their cell cycle, which is known as polyploidy. In the model cyanobacteria Synechococcus elongatus PCC 7942 and Synechocystis sp. PCC 6803, chromosome copy number (ploidy) is regulated in response to growth phase and environmental factors. In S. elongatus 7942, chromosome replication is asynchronous both among cells and chromosomes. Comparative analysis of S. elongatus 7942 and S. sp. 6803 revealed a variety of DNA replication mechanisms. In this review, the current knowledge of ploidy and DNA replication mechanisms in cyanobacteria is summarized together with information on the features common with plant chloroplasts. It is worth noting that the occurrence of polyploidy and its regulation are correlated with certain cyanobacterial lifestyles and are shared between some cyanobacteria and chloroplasts. ABBREVIATIONS NGS: next-generation sequencing; Repli-seq: replication sequencing; BrdU: 5-bromo-2'-deoxyuridine; TK: thymidine kinase; GCSI: GC skew index; PET: photosynthetic electron transport; RET: respiration electron transport; Cyt b6f complex: cytochrome b6f complex; PQ: plastoquinone; PC: plastocyanin.
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Affiliation(s)
- Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture , Tokyo, Japan
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33
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Fourier transform infrared and mass spectrometry analyses of a site-directed mutant of D1-Asp170 as a ligand to the water-oxidizing Mn4CaO5 cluster in photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148086. [DOI: 10.1016/j.bbabio.2019.148086] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 09/09/2019] [Accepted: 09/15/2019] [Indexed: 01/02/2023]
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34
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Kirtania P, Hódi B, Mallick I, Vass IZ, Fehér T, Vass I, Kós PB. A single plasmid based CRISPR interference in Synechocystis 6803 - A proof of concept. PLoS One 2019; 14:e0225375. [PMID: 31770415 PMCID: PMC6879144 DOI: 10.1371/journal.pone.0225375] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 11/02/2019] [Indexed: 11/20/2022] Open
Abstract
We developed a simple method to apply CRISPR interference by modifying an existing plasmid pCRISPathBrick containing the native S. pyogenes CRISPR assembly for Synechocystis PCC6803 and named it pCRPB1010. The technique presented here using deadCas9 is easier to implement for gene silencing in Synechocystis PCC6803 than other existing techniques as it circumvents the genome integration and segregation steps thereby significantly shortens the construction of the mutant strains. We executed CRISPR interference against well characterized photosynthetic genes to get a clear phenotype to validate the potential of pCRPB1010 and presented the work as a “proof of concept”. Targeting the non-template strand of psbO gene resulted in decreased amount of PsbO and 50% decrease in oxygen evolution rate. Targeting the template strand of psbA2 and psbA3 genes encoding the D1 subunit of photosystem II (PSII) using a single spacer against the common sequence span of the two genes, resulted in full inhibition of both genes, complete abolition of D1 protein synthesis, complete loss of oxygen evolution as well as photoautotrophic growth arrest. This is the first report of a single plasmid based, completely lesion free and episomal expression and execution of CRISPR interference in Synechocystis PCC6803.
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Affiliation(s)
- Prithwiraj Kirtania
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.,Doctoral School of Biology, University of Szeged, Szeged, Hungary
| | - Barbara Hódi
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.,Doctoral School of Biology, University of Szeged, Szeged, Hungary
| | - Ivy Mallick
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - István Zoltan Vass
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Tamás Fehér
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Imre Vass
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Peter B Kós
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.,Department of Biotechnology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
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Gale GAR, Schiavon Osorio AA, Mills LA, Wang B, Lea-Smith DJ, McCormick AJ. Emerging Species and Genome Editing Tools: Future Prospects in Cyanobacterial Synthetic Biology. Microorganisms 2019; 7:E409. [PMID: 31569579 PMCID: PMC6843473 DOI: 10.3390/microorganisms7100409] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 09/22/2019] [Accepted: 09/24/2019] [Indexed: 12/19/2022] Open
Abstract
Recent advances in synthetic biology and an emerging algal biotechnology market have spurred a prolific increase in the availability of molecular tools for cyanobacterial research. Nevertheless, work to date has focused primarily on only a small subset of model species, which arguably limits fundamental discovery and applied research towards wider commercialisation. Here, we review the requirements for uptake of new strains, including several recently characterised fast-growing species and promising non-model species. Furthermore, we discuss the potential applications of new techniques available for transformation, genetic engineering and regulation, including an up-to-date appraisal of current Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR associated protein (CRISPR/Cas) and CRISPR interference (CRISPRi) research in cyanobacteria. We also provide an overview of several exciting molecular tools that could be ported to cyanobacteria for more advanced metabolic engineering approaches (e.g., genetic circuit design). Lastly, we introduce a forthcoming mutant library for the model species Synechocystis sp. PCC 6803 that promises to provide a further powerful resource for the cyanobacterial research community.
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Affiliation(s)
- Grant A R Gale
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK.
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3BF, UK.
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FF, UK.
| | - Alejandra A Schiavon Osorio
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK.
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3BF, UK.
| | - Lauren A Mills
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Baojun Wang
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3BF, UK.
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FF, UK.
| | - David J Lea-Smith
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Alistair J McCormick
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK.
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3BF, UK.
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36
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Evaluation of New Genetic Toolkits and Their Role for Ethanol Production in Cyanobacteria. ENERGIES 2019. [DOI: 10.3390/en12183515] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Since the public awareness for climate change has risen, increasing scientific effort has been made to find and develop alternative resources and production processes to reduce the dependency on petrol-based fuels and chemicals of our society. Among others, the biotechnological fuel production, as for example fermenting sugar-rich crops to ethanol, is one of the main strategies. For this purpose, various classical production systems like Escherichia coli or Saccharomyces cerevisiae are used and have been optimized via genetic modifications. Despite the progress made, this strategy competes for nutritional resources and agricultural land. To overcome this problem, various attempts were made for direct photosynthetic driven ethanol synthesis with different microalgal species including cyanobacteria. However, compared to existing platforms, the development of cyanobacteria as photoautotrophic cell factories has just started, and accordingly, the ethanol yield of established production systems is still unreached. This is mainly attributed to low ethanol tolerance levels of cyanobacteria and there is still potential for optimizing the cyanobacteria towards alternative gene expression systems. Meanwhile, several improvements were made by establishing new toolboxes for synthetic biology offering new possibilities for advanced genetic modifications of cyanobacteria. Here, current achievements and innovations of those new molecular tools are discussed.
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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] [Abstract] [Key Words] [MESH Headings] [Grants] [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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38
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Polyploidy in halophilic archaea: regulation, evolutionary advantages, and gene conversion. Biochem Soc Trans 2019; 47:933-944. [PMID: 31189733 DOI: 10.1042/bst20190256] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/10/2019] [Accepted: 05/13/2019] [Indexed: 12/20/2022]
Abstract
All analyzed haloarachea are polyploid. In addition, haloarchaea contain more than one type of chromosome, and thus the gene dosage can be regulated independently on different replicons. Haloarchaea and several additional archaea have more than one replication origin on their major chromosome, in stark contrast with bacteria, which have a single replication origin. Two of these replication origins of Haloferax volcanii have been studied in detail and turned out to have very different properties. The chromosome copy number appears to be regulated in response to growth phases and environmental factors. Archaea typically contain about two Origin Recognition Complex (ORC) proteins, which are homologous to eukaryotic ORC proteins. However, haloarchaea are the only archaeal group that contains a multitude of ORC proteins. All 16 ORC protein paralogs from H. volcanii are involved in chromosome copy number regulation. Polyploidy has many evolutionary advantages for haloarchaea, e.g. a high resistance to desiccation, survival over geological times, and the relaxation of cell cycle-specific replication control. A further advantage is the ability to grow in the absence of external phosphate while using the many genome copies as internal phosphate storage polymers. Very efficient gene conversion operates in haloarchaea and results in the unification of genome copies. Taken together, haloarchaea are excellent models to study many aspects of genome biology in prokaryotes, exhibiting properties that have not been found in bacteria.
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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] [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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40
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Shalygin S, Huang IS, Allen EH, Burkholder JM, Zimba PV. Odorella benthonica gen. & sp. nov. (Pleurocapsales, Cyanobacteria): an odor and prolific toxin producer isolated from a California aqueduct. JOURNAL OF PHYCOLOGY 2019; 55:509-520. [PMID: 30637743 DOI: 10.1111/jpy.12834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 11/28/2018] [Indexed: 06/09/2023]
Abstract
Pleurocapsales are one of the least understood groups of cyanobacteria in terms of molecular systematics and biochemistry. Considering the high number of cryptic taxa within the Synechococcales and Oscillatoriales, it is likely that such taxa also occur in the Pleurocapsales. The new genus described in our research is the first known pleurocapsalean cryptic taxon. It produces off-flavor and a large number of bioactive metabolites (n = 38) some of which can be toxic including four known microcystins. Using a polyphasic approach, we propose the establishment of the genus Odorella with the new species O. benthonica from material originally isolated from the California Aqueduct near Los Angeles.
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Affiliation(s)
- Sergei Shalygin
- Center for Coastal Studies, Texas A&M University Corpus Christi, 6300 Ocean Drive, Corpus Christi, Texas, 78412, USA
| | - I-Shuo Huang
- Center for Coastal Studies, Texas A&M University Corpus Christi, 6300 Ocean Drive, Corpus Christi, Texas, 78412, USA
| | - Elle H Allen
- Center for Applied Aquatic Ecology, North Carolina State University, 620 Hutton Street Suite 104, Raleigh, North Carolina, 27606, USA
| | - JoAnn M Burkholder
- Center for Applied Aquatic Ecology, North Carolina State University, 620 Hutton Street Suite 104, Raleigh, North Carolina, 27606, USA
| | - Paul V Zimba
- Center for Coastal Studies, Texas A&M University Corpus Christi, 6300 Ocean Drive, Corpus Christi, Texas, 78412, USA
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Xia P, Ling H, Foo JL, Chang MW. Synthetic Biology Toolkits for Metabolic Engineering of Cyanobacteria. Biotechnol J 2019; 14:e1800496. [DOI: 10.1002/biot.201800496] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 02/19/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Peng‐Fei Xia
- Department of Biochemistry Yong Loo Lin School of MedicineNational University of Singapore8 Medical Drive Singapore 117597 Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI)National University of Singapore28 Medical Drive Singapore 117456 Singapore
| | - Hua Ling
- Department of Biochemistry Yong Loo Lin School of MedicineNational University of Singapore8 Medical Drive Singapore 117597 Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI)National University of Singapore28 Medical Drive Singapore 117456 Singapore
| | - Jee Loon Foo
- Department of Biochemistry Yong Loo Lin School of MedicineNational University of Singapore8 Medical Drive Singapore 117597 Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI)National University of Singapore28 Medical Drive Singapore 117456 Singapore
| | - Matthew Wook Chang
- Department of Biochemistry Yong Loo Lin School of MedicineNational University of Singapore8 Medical Drive Singapore 117597 Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI)National University of Singapore28 Medical Drive Singapore 117456 Singapore
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Abstract
Polyploidy has evolved many times across the kingdom of life. The relationship between cell growth and chromosome replication in bacteria has been studied extensively in monoploid model organisms such as Escherichia coli but not in polyploid organisms. Our study of the polyploid cyanobacterium Synechococcus elongatus demonstrates that replicating chromosome number is restricted and regulated by DnaA to maintain a relatively stable gene copy number/cell volume ratio during cell growth. In addition, our results suggest that polyploidy confers resistance to UV, which damages DNA. This compensatory polyploidy is likely necessitated by photosynthesis, which requires sunlight and generates damaging reactive oxygen species, and may also explain how polyploid bacteria can adapt to extreme environments with high risk of DNA damage. Homologous chromosome number (ploidy) has diversified among bacteria, archaea, and eukaryotes over evolution. In bacteria, model organisms such as Escherichia coli possess a single chromosome encoding the entire genome during slow growth. In contrast, other bacteria, including cyanobacteria, maintain multiple copies of individual chromosomes (polyploid). Although a correlation between ploidy level and cell size has been observed in bacteria and eukaryotes, it is poorly understood how replication of multicopy chromosomes is regulated and how ploidy level is adjusted to cell size. In addition, the advantages conferred by polyploidy are largely unknown. Here we show that only one or a few multicopy chromosomes are replicated at once in the cyanobacterium Synechococcus elongatus and that this restriction depends on regulation of DnaA activity. Inhibiting the DnaA intrinsic ATPase activity in S. elongatus increased the number of replicating chromosomes and chromosome number per cell but did not affect cell growth. In contrast, when cell growth rate was increased or decreased, DnaA level, DnaA activity, and the number of replicating chromosomes also increased or decreased in parallel, resulting in nearly constant chromosome copy number per unit of cell volume at constant temperature. When chromosome copy number was increased by inhibition of DnaA ATPase activity or reduced culture temperature, cells exhibited greater resistance to UV light. Thus, it is suggested that the stepwise replication of the genome enables cyanobacteria to maintain nearly constant gene copy number per unit of cell volume and that multicopy chromosomes function as backup genetic information to compensate for genomic damage.
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43
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Random Chromosome Partitioning in the Polyploid Bacterium Thermus thermophilus HB27. G3-GENES GENOMES GENETICS 2019; 9:1249-1261. [PMID: 30792193 PMCID: PMC6469415 DOI: 10.1534/g3.119.400086] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Little is known about chromosome segregation in polyploid prokaryotes. In this study, whether stringent or variable chromosome segregation occurs in polyploid thermophilic bacterium Thermus thermophilus was analyzed. A stable heterozygous strain (HL01) containing two antibiotic resistance markers at one gene locus was generated. The inheritance of the two alleles in the progeny of the heterozygous strain was then followed. During incubation without selection pressure, the fraction of heterozygous cells decreased and that of homozygous cells increased, while the relative abundance of each allele in the whole population remained constant, suggesting chromosome segregation had experienced random event. Consistently, in comparison with Bacillus subtilis in which the sister chromosomes were segregated equally, the ratios of DNA content in two daughter cells of T. thermophilus had a broader distribution and a larger standard deviation, indicating that the DNA content in the two daughter cells was not always identical. Further, the protein homologs (i.e., ParA and MreB) which have been suggested to be involved in bacterial chromosome partitioning did not actively participate in the chromosome segregation in T. thermophilus. Therefore, it seems that protein-based chromosome segregation machineries are less critical for the polyploid T. thermophilus, and chromosome segregation in this bacterium are not stringently controlled but tend to be variable, and random segregation can occur.
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44
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Zavřel T, Faizi M, Loureiro C, Poschmann G, Stühler K, Sinetova M, Zorina A, Steuer R, Červený J. Quantitative insights into the cyanobacterial cell economy. eLife 2019; 8:42508. [PMID: 30714903 PMCID: PMC6391073 DOI: 10.7554/elife.42508] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 02/01/2019] [Indexed: 01/27/2023] Open
Abstract
Phototrophic microorganisms are promising resources for green biotechnology. Compared to heterotrophic microorganisms, however, the cellular economy of phototrophic growth is still insufficiently understood. We provide a quantitative analysis of light-limited, light-saturated, and light-inhibited growth of the cyanobacterium Synechocystis sp. PCC 6803 using a reproducible cultivation setup. We report key physiological parameters, including growth rate, cell size, and photosynthetic activity over a wide range of light intensities. Intracellular proteins were quantified to monitor proteome allocation as a function of growth rate. Among other physiological acclimations, we identify an upregulation of the translational machinery and downregulation of light harvesting components with increasing light intensity and growth rate. The resulting growth laws are discussed in the context of a coarse-grained model of phototrophic growth and available data obtained by a comprehensive literature search. Our insights into quantitative aspects of cyanobacterial acclimations to different growth rates have implications to understand and optimize photosynthetic productivity.
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Affiliation(s)
- Tomáš Zavřel
- Laboratory of Adaptive BiotechnologiesGlobal Change Research Institute CASBrnoCzech Republic
| | - Marjan Faizi
- Institut für Biologie, Fachinstitut für Theoretische BiologieHumboldt-Universität zu BerlinBerlinGermany
| | - Cristina Loureiro
- Department of Applied PhysicsPolytechnic University of ValenciaValenciaSpain
| | - Gereon Poschmann
- Molecular Proteomics Laboratory, BMFZHeinrich-Heine-Universität DüsseldorfDüsseldorfGermany
| | - Kai Stühler
- Molecular Proteomics Laboratory, BMFZHeinrich-Heine-Universität DüsseldorfDüsseldorfGermany
| | - Maria Sinetova
- Timiryazev Institute of Plant PhysiologyRussian Academy of SciencesMoscowRussian Federation
| | - Anna Zorina
- Timiryazev Institute of Plant PhysiologyRussian Academy of SciencesMoscowRussian Federation
| | - Ralf Steuer
- Institut für Biologie, Fachinstitut für Theoretische BiologieHumboldt-Universität zu BerlinBerlinGermany
| | - Jan Červený
- Laboratory of Adaptive BiotechnologiesGlobal Change Research Institute CASBrnoCzech Republic
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45
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Behler J, Vijay D, Hess WR, Akhtar MK. CRISPR-Based Technologies for Metabolic Engineering in Cyanobacteria. Trends Biotechnol 2018; 36:996-1010. [DOI: 10.1016/j.tibtech.2018.05.011] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/24/2018] [Accepted: 05/29/2018] [Indexed: 12/16/2022]
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46
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Hu Y, Jiao J, Liu LX, Sun YW, Chen WF, Sui XH, Chen WX, Tian CF. Evidence for Phosphate Starvation of Rhizobia without Terminal Differentiation in Legume Nodules. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:1060-1068. [PMID: 29663866 DOI: 10.1094/mpmi-02-18-0031-r] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Phosphate homeostasis is tightly modulated in all organisms, including bacteria, which harbor both high- and low-affinity transporters acting under conditions of fluctuating phosphate levels. It was thought that nitrogen-fixing rhizobia, named bacteroids, inhabiting root nodules of legumes are not phosphate limited. Here, we show that the high-affinity phosphate transporter PstSCAB, rather than the low-affinity phosphate transporter Pit, is essential for effective nitrogen fixation of Sinorhizobium fredii in soybean nodules. Symbiotic and growth defects of the pst mutant can be effectively restored by knocking out PhoB, the transcriptional repressor of pit. The pst homologs of representative rhizobia were actively transcribed in bacteroids without terminal differentiation in nodules of diverse legumes (soybean, pigeonpea, cowpea, common bean, and Sophora flavescens) but exhibited a basal expression level in terminally differentiated bacteroids (alfalfa, pea, and peanut). Rhizobium leguminosarum bv. viciae Rlv3841 undergoes characteristic nonterminal and terminal differentiations in nodules of S. flavescens and pea, respectively. The pst mutant of Rlv3841 showed impaired adaptation to the nodule environment of S. flavescens but was indistinguishable from the wild-type strain in pea nodules. Taken together, root nodule rhizobia can be either phosphate limited or nonlimited regarding the rhizobial differentiation fate, which is a host-dependent feature.
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Affiliation(s)
- Yue Hu
- State Key Laboratory of Agrobiotechnology, MOA Key Laboratory of Soil Microbiology, Rhizobium Research Center, and College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Jian Jiao
- State Key Laboratory of Agrobiotechnology, MOA Key Laboratory of Soil Microbiology, Rhizobium Research Center, and College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Li Xue Liu
- State Key Laboratory of Agrobiotechnology, MOA Key Laboratory of Soil Microbiology, Rhizobium Research Center, and College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Yan Wei Sun
- State Key Laboratory of Agrobiotechnology, MOA Key Laboratory of Soil Microbiology, Rhizobium Research Center, and College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Wen Feng Chen
- State Key Laboratory of Agrobiotechnology, MOA Key Laboratory of Soil Microbiology, Rhizobium Research Center, and College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Xin Hua Sui
- State Key Laboratory of Agrobiotechnology, MOA Key Laboratory of Soil Microbiology, Rhizobium Research Center, and College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Wen Xin Chen
- State Key Laboratory of Agrobiotechnology, MOA Key Laboratory of Soil Microbiology, Rhizobium Research Center, and College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Chang Fu Tian
- State Key Laboratory of Agrobiotechnology, MOA Key Laboratory of Soil Microbiology, Rhizobium Research Center, and College of Biological Sciences, China Agricultural University, 100193, Beijing, China
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Perez-Sepulveda B, Pitt F, N'Guyen AN, Ratin M, Garczarek L, Millard A, Scanlan DJ. Relative stability of ploidy in a marine Synechococcus across various growth conditions. ENVIRONMENTAL MICROBIOLOGY REPORTS 2018; 10:428-432. [PMID: 29327508 DOI: 10.1111/1758-2229.12614] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 01/06/2018] [Indexed: 06/07/2023]
Abstract
Marine picocyanobacteria of the genus Synechococcus are ubiquitous phototrophs in oceanic systems. Consistent with these organisms occupying vast tracts of the nutrient impoverished ocean, most marine Synechococcus so far studied are monoploid, i.e., contain a single chromosome copy. The exception is the oligoploid strain Synechococcus sp. WH7803, which on average possesses around 4 chromosome copies. Here, we set out to understand the role of resource availability (through nutrient deplete growth) and physical stressors (UV, exposure to low and high temperature) in regulating ploidy level in this strain. Using qPCR to assay ploidy status we demonstrate the relative stability of chromosome copy number in Synechococcus sp. WH7803. Such robustness in maintaining an oligoploid status even under nutrient and physical stress is indicative of a fundamental role, perhaps facilitating recombination of damaged DNA regions as a result of prolonged exposure to oxidative stress, or allowing added flexibility in gene expression via possessing multiple alleles.
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Affiliation(s)
| | - Frances Pitt
- School of Life Sciences, University of Warwick, Coventry, UK
| | - An N N'Guyen
- Sorbonne Universités, UPMC-Université Paris 06, CNRS UMR 7144, Station Biologique, Roscoff, France
| | - Morgane Ratin
- Sorbonne Universités, UPMC-Université Paris 06, CNRS UMR 7144, Station Biologique, Roscoff, France
| | - Laurence Garczarek
- Sorbonne Universités, UPMC-Université Paris 06, CNRS UMR 7144, Station Biologique, Roscoff, France
| | - Andrew Millard
- Department of Infection Immunity and Inflammation, University of Leicester, Leicester, UK
| | - David J Scanlan
- School of Life Sciences, University of Warwick, Coventry, UK
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48
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Sun T, Li S, Song X, Diao J, Chen L, Zhang W. Toolboxes for cyanobacteria: Recent advances and future direction. Biotechnol Adv 2018; 36:1293-1307. [DOI: 10.1016/j.biotechadv.2018.04.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 04/09/2018] [Accepted: 04/26/2018] [Indexed: 12/20/2022]
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Paranjape SS, Shashidhar R. The ploidy of Vibrio cholerae is variable and is influenced by growth phase and nutrient levels. FEMS Microbiol Lett 2018; 364:4107777. [PMID: 28961807 DOI: 10.1093/femsle/fnx190] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 09/06/2017] [Indexed: 11/12/2022] Open
Abstract
The ploidy of Vibrio cholerae was quantified under different growth conditions. The V. cholerae was found to be (mero-) oligoploid or polyploid. The ploidy levels per cell were found to be growth phase regulated. The ploidy is highest during the early stationary phase (56-72 per cell) and lowest in the long-term starved state. In addition to growth phase, an external parameter such as nutrient level influences the ploidy, i.e. ploidy reduces rapidly at the onset of the starvation. The reduction is significant with P-value < 0.05 within 2 h of starvation. Even after prolonged starvation of 10 days, the ploidy number remained above 2 per cell. Failure to obtain a monoploid V. cholerae indicates that during starvation the genome is not distributed equally to daughter cells. The activity of DNase enzyme increased during starvation that decreased the ploidy. The ploidy was restored to the pre-starvation levels with nutrient supplementation.
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Affiliation(s)
- Shridhar S Paranjape
- Food Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, India and Life Sciences, Homi Bhabha National Institute (DAE-Deemed University), Trombay, Mumbai 400094, India
| | - Ravindranath Shashidhar
- Food Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, India and Life Sciences, Homi Bhabha National Institute (DAE-Deemed University), Trombay, Mumbai 400094, India
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Kelly CL, Taylor GM, Hitchcock A, Torres-Méndez A, Heap JT. A Rhamnose-Inducible System for Precise and Temporal Control of Gene Expression in Cyanobacteria. ACS Synth Biol 2018; 7:1056-1066. [PMID: 29544054 DOI: 10.1021/acssynbio.7b00435] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cyanobacteria are important for fundamental studies of photosynthesis and have great biotechnological potential. In order to better study and fully exploit these organisms, the limited repertoire of genetic tools and parts must be expanded. A small number of inducible promoters have been used in cyanobacteria, allowing dynamic external control of gene expression through the addition of specific inducer molecules. However, the inducible promoters used to date suffer from various drawbacks including toxicity of inducers, leaky expression in the absence of inducer and inducer photolability, the latter being particularly relevant to cyanobacteria, which, as photoautotrophs, are grown under light. Here we introduce the rhamnose-inducible rhaBAD promoter of Escherichia coli into the model freshwater cyanobacterium Synechocystis sp. PCC 6803 and demonstrate it has superior properties to previously reported cyanobacterial inducible promoter systems, such as a non-toxic, photostable, non-metabolizable inducer, a linear response to inducer concentration and crucially no basal transcription in the absence of inducer.
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Affiliation(s)
- Ciarán L. Kelly
- Imperial College Centre for Synthetic Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW7 2AZ, U.K
| | - George M. Taylor
- Imperial College Centre for Synthetic Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW7 2AZ, U.K
| | - Andrew Hitchcock
- Imperial College Centre for Synthetic Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW7 2AZ, U.K
| | - Antonio Torres-Méndez
- Imperial College Centre for Synthetic Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW7 2AZ, U.K
| | - John T. Heap
- Imperial College Centre for Synthetic Biology, Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW7 2AZ, U.K
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