1
|
Patyi G, Hódi B, Mallick I, Maróti G, Kós PB, Vass I. Investigation of singlet-oxygen-responsive genes in the cyanobacterium Synechocystis PCC 6803. PHYSIOLOGIA PLANTARUM 2024; 176:e14468. [PMID: 39140254 DOI: 10.1111/ppl.14468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 07/08/2024] [Accepted: 07/23/2024] [Indexed: 08/15/2024]
Abstract
Singlet oxygen (1O2) is an important reactive oxygen species whose formation by the type-II, light-dependent, photodynamic reaction is inevitable during photosynthetic processes. In the last decades, the recognition that 1O2 is not only a damaging agent, but can also affect gene expression and participates in signal transduction pathways has received increasing attention. However, contrary to several other taxa, 1O2-responsive genes have not been identified in the important cyanobacterial model organism Synechocystis PCC 6803. By using global transcript analysis we have identified a large set of Synechocystis genes, whose transcript levels were either enhanced or repressed in the presence of 1O2. Characteristic 1O2 responses were observed in several light-inducible genes of Synechocystis, especially in the hli (or scp) family encoding HLIP/SCP proteins involved in photoprotection. Other important 1O2-induced genes include components of the Photosystem II repair machinery (psbA2 and ftsH2, ftsH3), iron homeostasis genes isiA and idiA, the group 2 sigma factor sigD, some components of the transcriptomes induced by salt-, hyperosmotic and cold-stress, as well as several genes of unknown function. The most pronounced 1O2-induced upregulation was observed for the hliB and the co-transcribed lilA genes, whose deletion induced enhanced sensitivity against 1O2-mediated light damage. A bioreporter Synechocystis strain was created by fusing the hliB promoter to the bacterial luciferase (lux), which showed its utility for continuous monitoring of 1O2 concentrations inside the cell.
Collapse
Affiliation(s)
- Gábor Patyi
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Hungary
- Faculty of Science and Informatics, Doctoral School in Biology, University of Szeged, Szeged, Hungary
| | - Barbara Hódi
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Hungary
- Faculty of Science and Informatics, Doctoral School in Biology, University of Szeged, Szeged, Hungary
| | - Ivy Mallick
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Hungary
| | - Gergely Maróti
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Hungary
| | - Péter B Kós
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Hungary
- Department of Biotechnology, Faculty of Science and Informatics, University of Szeged, Hungary
| | - Imre Vass
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Hungary
| |
Collapse
|
2
|
Cheng J, Zhang K, Hou Y. The current situations and limitations of genetic engineering in cyanobacteria: a mini review. Mol Biol Rep 2023; 50:5481-5487. [PMID: 37119415 DOI: 10.1007/s11033-023-08456-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 04/12/2023] [Indexed: 05/01/2023]
Abstract
Cyanobacteria are an ancient group of photoautotrophic prokaryotes, and play an essential role in the global carbon cycle. They are also model organisms for studying photosynthesis and circadian regulation, and metabolic engineering and synthetic biology strategies grants light-driven biotechnological applications to cyanobacteria, especially for engineering cyanobacteria cells to achieve an efficient light-driven system for synthesizing any product of interest from renewable feedstocks. However, lower yield limits the potential of industrial application of cyanobacterial synthetic biology, and some key limitations must be overcome to realize the full biotechnological potential of these versatile microorganisms. Although genetic engineering toolkits for cyanobacteria have made some progress, the tools available still lag behind conventional heterotrophic microorganism. Consequently, this study describes the current situations and limitations of genetic engineering in cyanobacteria, and further improvements are proposed to improve the output of targeted products. We believe that cyanobacteria-mediated light-driven platforms towards efficient synthesis of green chemicals could unlock a bright future by developing the tools for strain manipulation and novel chassis organisms with excellent performance for biotechnological applications, which could also accelerate the advancement of bio-manufacturing industries.
Collapse
Affiliation(s)
- Jie Cheng
- School of Life Sciences, Liaocheng University, Liaocheng, 252000, China
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China
| | - Kaidian Zhang
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan Aquaculture Breeding Engineering Research Center, Hainan University, Haikou, 570100, China.
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China.
| | - Yuyong Hou
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
| |
Collapse
|
3
|
Patel VK, Das A, Kumari R, Kajla S. Recent progress and challenges in CRISPR-Cas9 engineered algae and cyanobacteria. ALGAL RES 2023. [DOI: 10.1016/j.algal.2023.103068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
|
4
|
Satta A, Esquirol L, Ebert BE. Current Metabolic Engineering Strategies for Photosynthetic Bioproduction in Cyanobacteria. Microorganisms 2023; 11:455. [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.
Collapse
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
| |
Collapse
|
5
|
Malihan‐Yap L, Grimm HC, Kourist R. Recent Advances in Cyanobacterial Biotransformations. CHEM-ING-TECH 2022. [DOI: 10.1002/cite.202200077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Lenny Malihan‐Yap
- Graz University of Technology Institute of Molecular Biotechnology NAWI Graz 8010 Graz Austria
| | - Hanna C. Grimm
- Graz University of Technology Institute of Molecular Biotechnology NAWI Graz 8010 Graz Austria
| | - Robert Kourist
- Graz University of Technology Institute of Molecular Biotechnology NAWI Graz 8010 Graz Austria
- ACIB GmbH 8010 Graz Austria
| |
Collapse
|
6
|
The Molecular Toolset and Techniques Required to Build Cyanobacterial Cell Factories. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2022. [DOI: 10.1007/10_2022_210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
7
|
Patyi G, Hódi B, Solymosi D, Vass I, Kós PB. Increased sensitivity of heavy metal bioreporters in transporter deficient Synechocystis PCC6803 mutants. PLoS One 2021; 16:e0261135. [PMID: 34914753 PMCID: PMC8675649 DOI: 10.1371/journal.pone.0261135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 11/28/2021] [Indexed: 11/30/2022] Open
Abstract
The detection and identification of heavy metal contaminants are becoming increasingly important as environmental pollution causes an ever-increasing health hazard in the last decades. Bacterial heavy metal reporters, which constitute an environmentally friendly and cheap approach, offer great help in this process. Although their application has great potential in the detection of heavy metal contamination, their sensitivity still needs to be improved. In this study, we describe a simple molecular biology approach to improve the sensitivity of bacterial heavy metal biosensors. The constructs are luxAB marker genes regulated by the promoters of heavy metal exporter genes. We constructed a mutant strain lacking the cluster of genes responsible for heavy metal transport and hence achieved increased intracellular heavy metal content of the Synechocystis PCC6803 cyanobacterium. Taking advantage of this increased intracellular heavy metal concentration the Ni2+; Co2+ and Zn2+ detection limits of the constructs were three to tenfold decreased compared to the sensitivity of the same constructs in the wild-type cyanobacterium.
Collapse
Affiliation(s)
- Gábor Patyi
- Institute of Plant Biology, Biological Research Centre of the Eötvös Lóránd Research Network, Szeged, Hungary
- Faculty of Science and Informatics, Doctoral School in Biology, University of Szeged, Szeged, Hungary
| | - Barbara Hódi
- Institute of Plant Biology, Biological Research Centre of the Eötvös Lóránd Research Network, Szeged, Hungary
- Faculty of Science and Informatics, Doctoral School in Biology, University of Szeged, Szeged, Hungary
| | - Dániel Solymosi
- Institute of Plant Biology, Biological Research Centre of the Eötvös Lóránd Research Network, Szeged, Hungary
| | - Imre Vass
- Institute of Plant Biology, Biological Research Centre of the Eötvös Lóránd Research Network, Szeged, Hungary
| | - Péter B. Kós
- Institute of Plant Biology, Biological Research Centre of the Eötvös Lóránd Research Network, Szeged, Hungary
- Department of Biotechnology, Faculty of Science and Informatics, Szeged University, Szeged, Hungary
- * E-mail:
| |
Collapse
|
8
|
Sengupta S, Sahasrabuddhe D, Wangikar PP. Transporter engineering for the development of cyanobacteria as cell factories: A text analytics guided survey. Biotechnol Adv 2021; 54:107816. [PMID: 34411662 DOI: 10.1016/j.biotechadv.2021.107816] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 08/10/2021] [Accepted: 08/13/2021] [Indexed: 11/28/2022]
Abstract
Cyanobacteria are attractive candidates for photoautotrophic production of platform chemicals due to their inherent ability to utilize carbon dioxide as the sole carbon source. Metabolic pathways can be engineered more readily in cyanobacteria compared to higher photosynthetic organisms. Although significant progress has been made in pathway engineering, intracellular accumulation of the product is a potential bottleneck in large-scale production. Likewise, substrate uptake is known to limit growth and product formation. These limitations can potentially be addressed by targeted and controlled expression of transporter proteins in the metabolically engineered strains. This review focuses on the transporters that have been explored in cyanobacteria. To highlight the progress on characterization and application of cyanobacterial transporters, we applied text analytics to extract relevant information from over 1000 publications. We have categorized the transporters based on their source, their function and the solute they transport. Further, the review provides insights into the potential of transporters in the metabolic engineering of cyanobacteria for improved product titer.
Collapse
Affiliation(s)
- Shinjinee Sengupta
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India; DBT-Pan IIT Center for Bioenergy, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Deepti Sahasrabuddhe
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India; DBT-Pan IIT Center for Bioenergy, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India; Wadhwani Research Center for Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Pramod P Wangikar
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India; DBT-Pan IIT Center for Bioenergy, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India; Wadhwani Research Center for Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| |
Collapse
|
9
|
Current knowledge and recent advances in understanding metabolism of the model cyanobacterium Synechocystis sp. PCC 6803. Biosci Rep 2021; 40:222317. [PMID: 32149336 PMCID: PMC7133116 DOI: 10.1042/bsr20193325] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/05/2020] [Accepted: 03/06/2020] [Indexed: 02/06/2023] Open
Abstract
Cyanobacteria are key organisms in the global ecosystem, useful models for studying metabolic and physiological processes conserved in photosynthetic organisms, and potential renewable platforms for production of chemicals. Characterizing cyanobacterial metabolism and physiology is key to understanding their role in the environment and unlocking their potential for biotechnology applications. Many aspects of cyanobacterial biology differ from heterotrophic bacteria. For example, most cyanobacteria incorporate a series of internal thylakoid membranes where both oxygenic photosynthesis and respiration occur, while CO2 fixation takes place in specialized compartments termed carboxysomes. In this review, we provide a comprehensive summary of our knowledge on cyanobacterial physiology and the pathways in Synechocystis sp. PCC 6803 (Synechocystis) involved in biosynthesis of sugar-based metabolites, amino acids, nucleotides, lipids, cofactors, vitamins, isoprenoids, pigments and cell wall components, in addition to the proteins involved in metabolite transport. While some pathways are conserved between model cyanobacteria, such as Synechocystis, and model heterotrophic bacteria like Escherichia coli, many enzymes and/or pathways involved in the biosynthesis of key metabolites in cyanobacteria have not been completely characterized. These include pathways required for biosynthesis of chorismate and membrane lipids, nucleotides, several amino acids, vitamins and cofactors, and isoprenoids such as plastoquinone, carotenoids, and tocopherols. Moreover, our understanding of photorespiration, lipopolysaccharide assembly and transport, and degradation of lipids, sucrose, most vitamins and amino acids, and haem, is incomplete. We discuss tools that may aid our understanding of cyanobacterial metabolism, notably CyanoSource, a barcoded library of targeted Synechocystis mutants, which will significantly accelerate characterization of individual proteins.
Collapse
|
10
|
Choi SY, Sim SJ, Ko SC, Son J, Lee JS, Lee HJ, Chang WS, Woo HM. Scalable Cultivation of Engineered Cyanobacteria for Squalene Production from Industrial Flue Gas in a Closed Photobioreactor. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:10050-10055. [PMID: 32851842 DOI: 10.1021/acs.jafc.0c03133] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Economically feasible photosynthetic cultivation of microalgal and cyanobacterial strains is crucial for the biological conversion of CO2 and potential CO2 mitigation to challenge global warming. To overcome the economic barriers, the production of value-added chemicals was desired by compensating for the overall processing cost. Here, we engineered cyanobacteria for photosynthetic squalene production and cultivated them in a scalable photobioreactor using industrial flue gas. First, an inducer-free gene expression system was developed for the cyanobacteria to lower production const. Then, the recombinant cyanobacteria were cultivated in a closed photobioreactor (100 L) using flue gas (5% CO2) as the sole carbon source under natural sunlight as the only energy source. Seasonal light intensities and temperatures were analyzed along with cyanobacterial cell growth and squalene production in August and October 2019. As a result, the effective irradiation hours were the most critical factor for the large-scale cultivation of cyanobacteria. Thus, an automated photobioprocess system will be developed based on the regional light sources.
Collapse
Affiliation(s)
- Sun Young Choi
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
- BioFoundry Research Center, Institute of Biotechnology and Bioengineering, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| | - Sang Jun Sim
- Department of Chemical and Biological Engineering, Korea University, Seoul 02841, South Korea
| | - Sung Cheon Ko
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| | - Jigyeong Son
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| | - Jeong Seop Lee
- Department of Chemical and Biological Engineering, Korea University, Seoul 02841, South Korea
| | - Hyun Jeong Lee
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
- BioFoundry Research Center, Institute of Biotechnology and Bioengineering, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| | - Won Seok Chang
- Research Institute, Korea District Heating Corporation, 186 Bundang-dong, Bundang-gu, Seongnam-si 13585, Gyeonggi-do, South Korea
| | - Han Min Woo
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
- BioFoundry Research Center, Institute of Biotechnology and Bioengineering, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| |
Collapse
|
11
|
Till P, Toepel J, Bühler B, Mach RL, Mach-Aigner AR. Regulatory systems for gene expression control in cyanobacteria. Appl Microbiol Biotechnol 2020; 104:1977-1991. [PMID: 31965222 PMCID: PMC7007895 DOI: 10.1007/s00253-019-10344-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/21/2019] [Accepted: 12/28/2019] [Indexed: 11/24/2022]
Abstract
As photosynthetic microbes, cyanobacteria are attractive hosts for the production of high-value molecules from CO2 and light. Strategies for genetic engineering and tightly controlled gene expression are essential for the biotechnological application of these organisms. Numerous heterologous or native promoter systems were used for constitutive and inducible expression, yet many of them suffer either from leakiness or from a low expression output. Anyway, in recent years, existing systems have been improved and new promoters have been discovered or engineered for cyanobacteria. Moreover, alternative tools and strategies for expression control such as riboswitches, riboregulators or genetic circuits have been developed. In this mini-review, we provide a broad overview on the different tools and approaches for the regulation of gene expression in cyanobacteria and explain their advantages and disadvantages.
Collapse
Affiliation(s)
- Petra Till
- Christian Doppler Laboratory for Optimized Expression of Carbohydrate-Active Enzymes, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Str. 1a, A-1060, Vienna, Austria
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Str. 1a, A-1060, Vienna, Austria
| | - Jörg Toepel
- Department of Solar Materials, Helmholtz-Centre for Environmental Research GmbH-UFZ, Permoserstrasse 15, 04318, Leipzig, Germany
| | - Bruno Bühler
- Department of Solar Materials, Helmholtz-Centre for Environmental Research GmbH-UFZ, Permoserstrasse 15, 04318, Leipzig, Germany
| | - Robert L Mach
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Str. 1a, A-1060, Vienna, Austria
| | - Astrid R Mach-Aigner
- Christian Doppler Laboratory for Optimized Expression of Carbohydrate-Active Enzymes, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Str. 1a, A-1060, Vienna, Austria.
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Str. 1a, A-1060, Vienna, Austria.
| |
Collapse
|
12
|
Yunus IS, Palma A, Trudeau DL, Tawfik DS, Jones PR. Methanol-free biosynthesis of fatty acid methyl ester (FAME) in Synechocystis sp. PCC 6803. Metab Eng 2020; 57:217-227. [DOI: 10.1016/j.ymben.2019.12.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/01/2019] [Accepted: 12/04/2019] [Indexed: 12/11/2022]
|
13
|
Kobayashi S, Nakajima M, Asano R, Ferreira EA, Abe K, Tamagnini P, Atsumi S, Sode K. Application of an engineered chromatic acclimation sensor for red-light-regulated gene expression in cyanobacteria. ALGAL RES 2019. [DOI: 10.1016/j.algal.2019.101691] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
14
|
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.
Collapse
|
15
|
Jin H, Lindblad P, Bhaya D. Building an Inducible T7 RNA Polymerase/T7 Promoter Circuit in Synechocystis sp. PCC6803. ACS Synth Biol 2019; 8:655-660. [PMID: 30935196 DOI: 10.1021/acssynbio.8b00515] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To develop tightly regulated orthogonal gene expression circuits in the photoautotrophic cyanobacterium Synechocystis sp. PCC6803 (Syn6803), we designed a circuit in which a native inducible promoter drives the expression of phage T7 RNA polymerase (T7RNAP). T7RNAP, in turn, specifically recognizes the T7 promoter that is designed to drive GFP expression. In Syn6803, this T7RNAP/T7promoter-GFP circuit produces high GFP fluorescence, which was further enhanced by using mutant T7 promoters. We also tested two orthogonal inducible promoters, Trc1O and L03, but these promoters drive T7RNAP to levels that are toxic in E. coli. Introduction of a protein degradation tag alleviated this problem. However, in Syn6803, these circuits did not function successfully. This highlights the underappreciated fact that similar circuits work with varying efficiencies in different chassis organisms. This lays the groundwork for developing new orthogonally controlled phage RNA polymerase-dependent expression systems in Syn6803.
Collapse
Affiliation(s)
- Haojie Jin
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, United States
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Box 523, SE 75120, Uppsala, Sweden
| | - Devaki Bhaya
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, United States
| |
Collapse
|
16
|
Gordon GC, Pfleger BF. Regulatory Tools for Controlling Gene Expression in Cyanobacteria. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1080:281-315. [PMID: 30091100 PMCID: PMC6662922 DOI: 10.1007/978-981-13-0854-3_12] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cyanobacteria are attractive hosts for converting carbon dioxide and sunlight into desirable chemical products. To engineer these organisms and manipulate their metabolic pathways, the biotechnology community has developed genetic tools to control gene expression. Many native cyanobacterial promoters and related sequence elements have been used to regulate genes of interest, and heterologous tools that use non-native small molecules to induce gene expression have been demonstrated. Overall, IPTG-based induction systems seem to be leaky and initially demonstrate small dynamic ranges in cyanobacteria. Consequently, a variety of other induction systems have been optimized to enable tighter control of gene expression. Tools require significant optimization because they function quite differently in cyanobacteria when compared to analogous use in model heterotrophs. We hypothesize that these differences are due to fundamental differences in physiology between organisms. This review is not intended to summarize all known products made in cyanobacteria nor the performance (titer, rate, yield) of individual strains, but instead will focus on the genetic tools and the inherent aspects of cellular physiology that influence gene expression in cyanobacteria.
Collapse
Affiliation(s)
- Gina C Gordon
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Brian F Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA.
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA.
| |
Collapse
|
17
|
Synthetic Gene Regulation in Cyanobacteria. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1080:317-355. [DOI: 10.1007/978-981-13-0854-3_13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
|
18
|
Ferreira EA, Pacheco CC, Pinto F, Pereira J, Lamosa P, Oliveira P, Kirov B, Jaramillo A, Tamagnini P. Expanding the toolbox for Synechocystis sp. PCC 6803: validation of replicative vectors and characterization of a novel set of promoters. Synth Biol (Oxf) 2018; 3:ysy014. [PMID: 32995522 PMCID: PMC7445879 DOI: 10.1093/synbio/ysy014] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 07/27/2018] [Accepted: 07/30/2018] [Indexed: 11/14/2022] Open
Abstract
Cyanobacteria are promising 'low-cost' cell factories since they have minimal nutritional requirements, high metabolic plasticity and can use sunlight and CO2 as energy and carbon sources. The unicellular Synechocystis sp. PCC 6803, already considered the 'green' Escherichia coli, is the best studied cyanobacterium but to be used as an efficient and robust photoautotrophic chassis it requires a customized and well-characterized toolbox. In this context, we evaluated the possibility of using three self-replicative vectors from the Standard European Vector Architecture (SEVA) repository to transform Synechocystis. Our results demonstrated that the presence of the plasmid does not lead to an evident phenotype or hindered Synechocystis growth, being the vast majority of the cells able to retain the replicative plasmid even in the absence of selective pressure. In addition, a set of heterologous and redesigned promoters were characterized exhibiting a wide range of activities compared to the reference P rnpB , three of which could be efficiently repressed. As a proof-of-concept, from the expanded toolbox, one promoter was selected and assembled with the ggpS gene [encoding one of the proteins involved in the synthesis of the native compatible solute glucosylglycerol (GG)] and the synthetic device was introduced into Synechocystis using one of the SEVA plasmids. The presence of this device restored the production of the GG in a ggpS deficient mutant validating the functionality of the tools/device developed in this study.
Collapse
Affiliation(s)
- Eunice A Ferreira
- i3S - Instituto de Investigação e Inovação em Saúde Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular Universidade do Porto, Porto, Portugal.,ICBAS - Instituto de Ciências Biomédicas Abel Salazar Universidade do Porto, Porto, Portugal
| | - Catarina C Pacheco
- i3S - Instituto de Investigação e Inovação em Saúde Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular Universidade do Porto, Porto, Portugal
| | - Filipe Pinto
- i3S - Instituto de Investigação e Inovação em Saúde Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular Universidade do Porto, Porto, Portugal.,School of Biological Sciences, University of Edinburgh, Edinburgh, UK.,Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, UK
| | - José Pereira
- i3S - Instituto de Investigação e Inovação em Saúde Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular Universidade do Porto, Porto, Portugal
| | - Pedro Lamosa
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Oeiras, Portugal
| | - Paulo Oliveira
- i3S - Instituto de Investigação e Inovação em Saúde Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular Universidade do Porto, Porto, Portugal
| | - Boris Kirov
- CNRS-UMR8030 Laboratoire iSSB and Université Paris-Saclay and Université d'Évry and CEA DRF, IG, Genoscope, Évry, France.,ANP - Faculty of Automatics, TU - Sofia, Sofia, Bulgaria.,BioInfoTech Lab - RDIC, Sofia Tech Park, Sofia, Bulgaria
| | - Alfonso Jaramillo
- CNRS-UMR8030 Laboratoire iSSB and Université Paris-Saclay and Université d'Évry and CEA DRF, IG, Genoscope, Évry, France.,Warwick Integrative Synthetic Biology Centre and School of Life Sciences, University of Warwick, Coventry, UK.,Institute for Integrative Systems Biology (I2SysBio) University of Valencia-CSIC, Paterna, Spain
| | - Paula Tamagnini
- i3S - Instituto de Investigação e Inovação em Saúde Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular Universidade do Porto, Porto, Portugal.,Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Porto, Portugal
| |
Collapse
|
19
|
Liu D, Pakrasi HB. Exploring native genetic elements as plug-in tools for synthetic biology in the cyanobacterium Synechocystis sp. PCC 6803. Microb Cell Fact 2018; 17:48. [PMID: 29580240 PMCID: PMC5868059 DOI: 10.1186/s12934-018-0897-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 03/21/2018] [Indexed: 11/24/2022] Open
Abstract
Background The unicellular cyanobacterium Synechocystis sp. PCC 6803 has been widely used as a photoautotrophic host for synthetic biology studies. However, as a green chassis to capture CO2 for biotechnological applications, the genetic toolbox for Synechocystis 6803 is still a limited factor. Results We systematically characterized endogenous genetic elements of Synechocystis 6803, including promoters, ribosome binding sites, transcription terminators, and plasmids. Expression from twelve native promoters was compared by measuring fluorescence from the reporter protein EYFP in an identical setup, exhibiting an 8000-fold range of promoter activities. Moreover, we measured the strength of twenty native ribosome binding sites and eight native terminators, indicating their influence on the expression of the reporter genes. In addition, two shuttle vectors, pCA-UC118 and pCB-SC101, capable of replication in both Synechocystis 6803 and E. coli were constructed. Expression of reporter proteins were significantly enhanced in cells containing these new plasmids, thus providing superior gene expression platforms in this cyanobacterium. Conclusions The results of this study provide useful and well characterized native tools for bioengineering work in the model cyanobacterium Synechocystis 6803. Electronic supplementary material The online version of this article (10.1186/s12934-018-0897-8) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Deng Liu
- Department of Biology, Washington University, Campus Box 1137, One Brookings Drive, St. Louis, MO, 63130, USA
| | - Himadri B Pakrasi
- Department of Biology, Washington University, Campus Box 1137, One Brookings Drive, St. Louis, MO, 63130, USA.
| |
Collapse
|
20
|
Loeschcke A, Dienst D, Wewer V, Hage-Hülsmann J, Dietsch M, Kranz-Finger S, Hüren V, Metzger S, Urlacher VB, Gigolashvili T, Kopriva S, Axmann IM, Drepper T, Jaeger KE. The photosynthetic bacteria Rhodobacter capsulatus and Synechocystis sp. PCC 6803 as new hosts for cyclic plant triterpene biosynthesis. PLoS One 2017; 12:e0189816. [PMID: 29281679 PMCID: PMC5744966 DOI: 10.1371/journal.pone.0189816] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 12/01/2017] [Indexed: 11/18/2022] Open
Abstract
Cyclic triterpenes constitute one of the most diverse groups of plant natural products. Besides the intriguing biochemistry of their biosynthetic pathways, plant triterpenes exhibit versatile bioactivities, including antimicrobial effects against plant and human pathogens. While prokaryotes have been extensively used for the heterologous production of other classes of terpenes, the synthesis of cyclic triterpenes, which inherently includes the two-step catalytic formation of the universal linear precursor 2,3-oxidosqualene, is still a major challenge. We thus explored the suitability of the metabolically versatile photosynthetic α-proteobacterium Rhodobacter capsulatus SB1003 and cyanobacterium Synechocystis sp. PCC 6803 as alternative hosts for biosynthesis of cyclic plant triterpenes. Therefore, 2,3-oxidosqualene production was implemented and subsequently combined with different cyclization reactions catalyzed by the representative oxidosqualene cyclases CAS1 (cycloartenol synthase), LUP1 (lupeol synthase), THAS1 (thalianol synthase) and MRN1 (marneral synthase) derived from model plant Arabidopsis thaliana. While successful accumulation of 2,3-oxidosqualene could be detected by LC-MS analysis in both hosts, cyclase expression resulted in differential production profiles. CAS1 catalyzed conversion to only cycloartenol, but expression of LUP1 yielded lupeol and a triterpenoid matching an oxidation product of lupeol, in both hosts. In contrast, THAS1 expression did not lead to cyclic product formation in either host, whereas MRN1-dependent production of marnerol and hydroxymarnerol was observed in Synechocystis but not in R. capsulatus. Our findings thus indicate that 2,3-oxidosqualene cyclization in heterologous phototrophic bacteria is basically feasible but efficient conversion depends on both the respective cyclase enzyme and individual host properties. Therefore, photosynthetic α-proteo- and cyanobacteria are promising alternative candidates for providing new bacterial access to the broad class of triterpenes for biotechnological applications.
Collapse
Affiliation(s)
- Anita Loeschcke
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich, Jülich, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS)
| | - Dennis Dienst
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Vera Wewer
- Cluster of Excellence on Plant Sciences (CEPLAS)
- MS Platform, Department of Biology, University of Cologne, Cologne, Germany
| | - Jennifer Hage-Hülsmann
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich, Jülich, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS)
| | - Maximilian Dietsch
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sarah Kranz-Finger
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Institute of Biochemistry II, Department of Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Vanessa Hüren
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sabine Metzger
- Cluster of Excellence on Plant Sciences (CEPLAS)
- MS Platform, Department of Biology, University of Cologne, Cologne, Germany
| | - Vlada B. Urlacher
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Institute of Biochemistry II, Department of Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Tamara Gigolashvili
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Botanical Institute, University of Cologne, Cologne, Germany
| | - Stanislav Kopriva
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Botanical Institute, University of Cologne, Cologne, Germany
| | - Ilka M. Axmann
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Institute for Synthetic Microbiology, Department of Biology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- * E-mail: (IMA); (TD)
| | - Thomas Drepper
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich, Jülich, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS)
- * E-mail: (IMA); (TD)
| | - Karl-Erich Jaeger
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf, Forschungszentrum Jülich, Jülich, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS)
- Institute of Bio- and Geosciences (IBG-1), Forschungszentrum Jülich, Jülich, Germany
| |
Collapse
|
21
|
Ueno K, Sakai Y, Shono C, Sakamoto I, Tsukakoshi K, Hihara Y, Sode K, Ikebukuro K. Applying a riboregulator as a new chromosomal gene regulation tool for higher glycogen production in Synechocystis sp. PCC 6803. Appl Microbiol Biotechnol 2017; 101:8465-8474. [PMID: 29038975 DOI: 10.1007/s00253-017-8570-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 09/18/2017] [Accepted: 09/26/2017] [Indexed: 11/29/2022]
Abstract
Cyanobacteria are one of the most attractive hosts for biofuel production; however, genetic approaches to regulate specific chromosomal genes in cyanobacteria remain limited. With the aim of developing a novel method to regulate chromosomal gene expression in cyanobacteria, we focused on riboregulatory technology. Riboregulators are composed of two RNA fragments whose interaction leads to target gene regulation with high specificity. In this study, we inserted a riboregulator sequence upstream of the chromosomal gene encoding AbrB-like transcriptional regulator, cyAbrB2, to investigate the utility of this tool. The inserted riboregulator was able to regulate cyabrB2 gene expression, with a high ON-OFF ratio up to approximately 50-fold. The transcription levels of several genes for which cyAbrB2 acts as a transcriptional upregulator were also decreased. Further, the cyAbrB2 expression-repressed mutant showed high glycogen accumulation, equivalent to that in the cyabrB2 deletion mutant (ΔcyabrB2). Phenotypic similarities between the cyabrB2 expression-repressed mutant and the ΔcyabrB2 mutant suggest that the riboregulator can potentially be used as a new chromosomal gene regulation tool in cyanobacteria.
Collapse
Affiliation(s)
- Kinuko Ueno
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Yuta Sakai
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Chika Shono
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Ippei Sakamoto
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Kaori Tsukakoshi
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Yukako Hihara
- Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570, Japan
| | - Koji Sode
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Kazunori Ikebukuro
- Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan.
| |
Collapse
|
22
|
Englund E, Liang F, Lindberg P. Evaluation of promoters and ribosome binding sites for biotechnological applications in the unicellular cyanobacterium Synechocystis sp. PCC 6803. Sci Rep 2016; 6:36640. [PMID: 27857166 PMCID: PMC5114575 DOI: 10.1038/srep36640] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 10/17/2016] [Indexed: 01/21/2023] Open
Abstract
For effective metabolic engineering, a toolbox of genetic components that enables predictable control of gene expression is needed. Here we present a systematic study of promoters and ribosome binding sites in the unicellular cyanobacterium Synechocystis sp. PCC 6803. A set of metal ion inducible promoters from Synechocystis were compared to commonly used constitutive promoters, by measuring fluorescence of a reporter protein in a standardized setting to allow for accurate comparisons of promoter activity. The most versatile and useful promoter was found to be PnrsB, which from a relatively silent expression could be induced almost 40-fold, nearly up to the activity of the strong psbA2 promoter. By varying the concentrations of the two metal ion inducers Ni2+ and Co2+, expression from the promoter was highly tunable, results that were reproduced with PnrsB driving ethanol production. The activities of several ribosomal binding sites were also measured, and tested in parallel in Synechocystis and Escherichia coli. The results of the study add useful information to the Synechocystis genetic toolbox for biotechnological applications.
Collapse
Affiliation(s)
- Elias Englund
- Department of Chemistry - Ångström, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden
| | - Feiyan Liang
- Department of Chemistry - Ångström, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden
| | - Pia Lindberg
- Department of Chemistry - Ångström, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden
| |
Collapse
|
23
|
Čelešnik H, Tanšek A, Tahirović A, Vižintin A, Mustar J, Vidmar V, Dolinar M. Biosafety of biotechnologically important microalgae: intrinsic suicide switch implementation in cyanobacterium Synechocystis sp. PCC 6803. Biol Open 2016; 5:519-28. [PMID: 27029902 PMCID: PMC4890671 DOI: 10.1242/bio.017129] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
In recent years, photosynthetic autotrophic cyanobacteria have attracted interest for biotechnological applications for sustainable production of valuable metabolites. Although biosafety issues can have a great impact on public acceptance of cyanobacterial biotechnology, biosafety of genetically modified cyanobacteria has remained largely unexplored. We set out to incorporate biocontainment systems in the model cyanobacterium Synechocystis sp. PCC 6803. Plasmid-encoded safeguards were constructed using the nonspecific nuclease NucA from Anabaena combined with different metal-ion inducible promoters. In this manner, conditional lethality was dependent on intracellular DNA degradation for regulated autokilling as well as preclusion of horizontal gene transfer. In cells carrying the suicide switch comprising the nucA gene fused to a variant of the copM promoter, efficient inducible autokilling was elicited. Parallel to nuclease-based safeguards, cyanobacterial toxin/antitoxin (TA) modules were examined in biosafety switches. Rewiring of Synechocystis TA pairs ssr1114/slr0664 and slr6101/slr6100 for conditional lethality using metal-ion responsive promoters resulted in reduced growth, rather than cell killing, suggesting cells could cope with elevated toxin levels. Overall, promoter properties and translation efficiency influenced the efficacy of biocontainment systems. Several metal-ion promoters were tested in the context of safeguards, and selected promoters, including a nrsB variant, were characterized by beta-galactosidase reporter assay. Summary: Biosafety of biotechnologically important microalgae was addressed by suicide switch implementation in cyanobacterium Synechocystis sp. PCC 6803. This is the first report of biocontainment safeguards in cyanobacteria.
Collapse
Affiliation(s)
- Helena Čelešnik
- Chair of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana 1000, Slovenia
| | - Anja Tanšek
- Chair of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana 1000, Slovenia
| | - Aneja Tahirović
- Chair of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana 1000, Slovenia
| | - Angelika Vižintin
- Chair of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana 1000, Slovenia
| | - Jernej Mustar
- Chair of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana 1000, Slovenia
| | - Vita Vidmar
- Chair of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana 1000, Slovenia
| | - Marko Dolinar
- Chair of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana 1000, Slovenia
| |
Collapse
|
24
|
Ohbayashi R, Akai H, Yoshikawa H, Hess WR, Watanabe S. A tightly inducible riboswitch system in Synechocystis sp. PCC 6803. J GEN APPL MICROBIOL 2016; 62:154-9. [DOI: 10.2323/jgam.2016.02.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Ryudo Ohbayashi
- Department of Bioscience, Tokyo University of Agriculture
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)
| | - Hideto Akai
- Department of Bioscience, Tokyo University of Agriculture
| | - Hirofumi Yoshikawa
- Department of Bioscience, Tokyo University of Agriculture
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)
| | - Wolfgang R. Hess
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg
| | | |
Collapse
|
25
|
Camsund D, Lindblad P. Engineered transcriptional systems for cyanobacterial biotechnology. Front Bioeng Biotechnol 2014; 2:40. [PMID: 25325057 PMCID: PMC4181335 DOI: 10.3389/fbioe.2014.00040] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 09/15/2014] [Indexed: 11/13/2022] Open
Abstract
Cyanobacteria can function as solar-driven biofactories thanks to their ability to perform photosynthesis and the ease with which they are genetically modified. In this review, we discuss transcriptional parts and promoters available for engineering cyanobacteria. First, we go through special cyanobacterial characteristics that may impact engineering, including the unusual cyanobacterial RNA polymerase, sigma factors and promoter types, mRNA stability, circadian rhythm, and gene dosage effects. Then, we continue with discussing component characteristics that are desirable for synthetic biology approaches, including decoupling, modularity, and orthogonality. We then summarize and discuss the latest promoters for use in cyanobacteria regarding characteristics such as regulation, strength, and dynamic range and suggest potential uses. Finally, we provide an outlook and suggest future developments that would advance the field and accelerate the use of cyanobacteria for renewable biotechnology.
Collapse
Affiliation(s)
- Daniel Camsund
- Science for Life Laboratory, Microbial Chemistry, Department of Chemistry - Ångström, Uppsala University , Uppsala , Sweden
| | - Peter Lindblad
- Science for Life Laboratory, Microbial Chemistry, Department of Chemistry - Ångström, Uppsala University , Uppsala , Sweden
| |
Collapse
|
26
|
Coregulated genes link sulfide:quinone oxidoreductase and arsenic metabolism in Synechocystis sp. strain PCC6803. J Bacteriol 2014; 196:3430-40. [PMID: 25022856 DOI: 10.1128/jb.01864-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although the biogeochemistry of the two environmentally hazardous compounds arsenic and sulfide has been extensively investigated, the biological interference of these two toxic but potentially energy-rich compounds has only been hypothesized and indirectly proven. Here we provide direct evidence for the first time that in the photosynthetic model organism Synechocystis sp. strain PCC6803 the two metabolic pathways are linked by coregulated genes that are involved in arsenic transport, sulfide oxidation, and probably in sulfide-based alternative photosynthesis. Although Synechocystis sp. strain PCC6803 is an obligate photoautotrophic cyanobacterium that grows via oxygenic photosynthesis, we discovered that specific genes are activated in the presence of sulfide or arsenite to exploit the energy potentials of these chemicals. These genes form an operon that we termed suoRSCT, located on a transposable element of type IS4 on the plasmid pSYSM of the cyanobacterium. suoS (sll5036) encodes a light-dependent, type I sulfide:quinone oxidoreductase. The suoR (sll5035) gene downstream of suoS encodes a regulatory protein that belongs to the ArsR-type repressors that are normally involved in arsenic resistance. We found that this repressor has dual specificity, resulting in 200-fold induction of the operon upon either arsenite or sulfide exposure. The suoT gene encodes a transmembrane protein similar to chromate transporters but in fact functioning as an arsenite importer at permissive concentrations. We propose that the proteins encoded by the suoRSCT operon might have played an important role under anaerobic, reducing conditions on primordial Earth and that the operon was acquired by the cyanobacterium via horizontal gene transfer.
Collapse
|
27
|
Berla BM, Saha R, Immethun CM, Maranas CD, Moon TS, Pakrasi HB. Synthetic biology of cyanobacteria: unique challenges and opportunities. Front Microbiol 2013; 4:246. [PMID: 24009604 PMCID: PMC3755261 DOI: 10.3389/fmicb.2013.00246] [Citation(s) in RCA: 176] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 08/05/2013] [Indexed: 12/31/2022] Open
Abstract
Photosynthetic organisms, and especially cyanobacteria, hold great promise as sources of renewably-produced fuels, bulk and specialty chemicals, and nutritional products. Synthetic biology tools can help unlock cyanobacteria's potential for these functions, but unfortunately tool development for these organisms has lagged behind that for S. cerevisiae and E. coli. While these organisms may in many cases be more difficult to work with as “chassis” strains for synthetic biology than certain heterotrophs, the unique advantages of autotrophs in biotechnology applications as well as the scientific importance of improved understanding of photosynthesis warrant the development of these systems into something akin to a “green E. coli.” In this review, we highlight unique challenges and opportunities for development of synthetic biology approaches in cyanobacteria. We review classical and recently developed methods for constructing targeted mutants in various cyanobacterial strains, and offer perspective on what genetic tools might most greatly expand the ability to engineer new functions in such strains. Similarly, we review what genetic parts are most needed for the development of cyanobacterial synthetic biology. Finally, we highlight recent methods to construct genome-scale models of cyanobacterial metabolism and to use those models to measure properties of autotrophic metabolism. Throughout this paper, we discuss some of the unique challenges of a diurnal, autotrophic lifestyle along with how the development of synthetic biology and biotechnology in cyanobacteria must fit within those constraints.
Collapse
Affiliation(s)
- Bertram M Berla
- Department of Energy, Environmental, and Chemical Engineering, Washington University St. Louis, MO, USA
| | | | | | | | | | | |
Collapse
|