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Böhm C, Inckemann R, Burgis M, Baumann J, Brinkmann CK, Lipinska KE, Gilles S, Freudigmann J, Seiler VN, Clark LG, Jewett MC, Voll LM, Niederholtmeyer H. Chloroplast Cell-Free Systems from Different Plant Species as a Rapid Prototyping Platform. ACS Synth Biol 2024; 13:2412-2424. [PMID: 39028299 PMCID: PMC11334176 DOI: 10.1021/acssynbio.4c00117] [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: 02/19/2024] [Revised: 04/30/2024] [Accepted: 05/01/2024] [Indexed: 07/20/2024]
Abstract
Climate change poses a significant threat to global agriculture, necessitating innovative solutions. Plant synthetic biology, particularly chloroplast engineering, holds promise as a viable approach to this challenge. Chloroplasts present a variety of advantageous traits for genetic engineering, but the development of genetic tools and genetic part characterization in these organelles is hindered by the lengthy time scales required to generate transplastomic organisms. To address these challenges, we have established a versatile protocol for generating highly active chloroplast-based cell-free gene expression (CFE) systems derived from a diverse range of plant species, including wheat (monocot), spinach, and poplar trees (dicots). We show that these systems work with conventionally used T7 RNA polymerase as well as the endogenous chloroplast polymerases, allowing for detailed characterization and prototyping of regulatory sequences at both transcription and translation levels. To demonstrate the platform for characterization of promoters and 5' and 3' untranslated regions (UTRs) in higher plant chloroplast gene expression, we analyze a collection of 23 5'UTRs, 10 3'UTRs, and 6 chloroplast promoters, assessed their expression in spinach and wheat extracts, and found consistency in expression patterns, suggesting cross-species compatibility. Looking forward, our chloroplast CFE systems open new avenues for plant synthetic biology, offering prototyping tools for both understanding gene expression and developing engineered plants, which could help meet the demands of a changing global climate.
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Affiliation(s)
- Clemens
V. Böhm
- Max-Planck
Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- Center
for Synthetic Microbiology, Philipps-Universität
Marburg, 35032 Marburg, Germany
| | - René Inckemann
- Max-Planck
Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- Center
for Synthetic Microbiology, Philipps-Universität
Marburg, 35032 Marburg, Germany
| | - Michael Burgis
- Center
for Synthetic Microbiology, Philipps-Universität
Marburg, 35032 Marburg, Germany
| | - Jessica Baumann
- Molecular
Plant Physiology, Philipps-Universität
Marburg, 35043 Marburg, Germany
| | | | - Katarzyna E. Lipinska
- Max-Planck
Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- Center
for Synthetic Microbiology, Philipps-Universität
Marburg, 35032 Marburg, Germany
| | - Sara Gilles
- Max-Planck
Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- Center
for Synthetic Microbiology, Philipps-Universität
Marburg, 35032 Marburg, Germany
| | - Jonas Freudigmann
- Molecular
Plant Physiology, Philipps-Universität
Marburg, 35043 Marburg, Germany
| | - Vinca N. Seiler
- Molecular
Plant Physiology, Philipps-Universität
Marburg, 35043 Marburg, Germany
| | - Lauren G. Clark
- Department
of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Michael C. Jewett
- Department
of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Lars M. Voll
- Center
for Synthetic Microbiology, Philipps-Universität
Marburg, 35032 Marburg, Germany
- Molecular
Plant Physiology, Philipps-Universität
Marburg, 35043 Marburg, Germany
| | - Henrike Niederholtmeyer
- Max-Planck
Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- Center
for Synthetic Microbiology, Philipps-Universität
Marburg, 35032 Marburg, Germany
- Technical
University of Munich, Campus Straubing for Biotechnology and Sustainability, 94315 Straubing, Germany
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2
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Goold HD, Moseley JL, Lauersen KJ. The synthetic future of algal genomes. CELL GENOMICS 2024; 4:100505. [PMID: 38395701 PMCID: PMC10943592 DOI: 10.1016/j.xgen.2024.100505] [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: 09/28/2023] [Revised: 12/18/2023] [Accepted: 01/24/2024] [Indexed: 02/25/2024]
Abstract
Algae are diverse organisms with significant biotechnological potential for resource circularity. Taking inspiration from fermentative microbes, engineering algal genomes holds promise to broadly expand their application ranges. Advances in genome sequencing with improvements in DNA synthesis and delivery techniques are enabling customized molecular tool development to confer advanced traits to algae. Efforts to redesign and rebuild entire genomes to create fit-for-purpose organisms currently being explored in heterotrophic prokaryotes and eukaryotic microbes could also be applied to photosynthetic algae. Future algal genome engineering will enhance yields of native products and permit the expression of complex biochemical pathways to produce novel metabolites from sustainable inputs. We present a historical perspective on advances in engineering algae, discuss the requisite genetic traits to enable algal genome optimization, take inspiration from whole-genome engineering efforts in other microbes for algal systems, and present candidate algal species in the context of these engineering goals.
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Affiliation(s)
- Hugh D Goold
- New South Wales Department of Primary Industries, Orange, NSW 2800, Australia; ARC Center of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW 2109, Australia; School of Natural Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Jeffrey L Moseley
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA; Division of Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Phycoil Biotechnology International, Inc., Fremont, CA 94538, USA
| | - Kyle J Lauersen
- Bioengineering Program, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia.
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3
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Tanwar N, Arya SS, Rookes JE, Cahill DM, Lenka SK, Bansal KC. Prospects of chloroplast metabolic engineering for developing nutrient-dense food crops. Crit Rev Biotechnol 2023; 43:1001-1018. [PMID: 35815847 DOI: 10.1080/07388551.2022.2092717] [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: 01/31/2022] [Accepted: 05/29/2022] [Indexed: 11/03/2022]
Abstract
Addressing nutritional deficiencies in food crops through biofortification is a sustainable approach to tackling malnutrition. Biofortification is continuously being attempted through conventional breeding as well as through various plant biotechnological interventions, ranging from molecular breeding to genetic engineering and genome editing for enriching crops with various health-promoting metabolites. Genetic engineering is used for the rational incorporation of desired nutritional traits in food crops and predominantly operates through nuclear and chloroplast genome engineering. In the recent past, chloroplast engineering has been deployed as a strategic tool to develop model plants with enhanced nutritional traits due to the various advantages it offers over nuclear genome engineering. However, this approach needs to be extended for the nutritional enhancement of major food crops. Further, this platform could be combined with strategies, such as synthetic biology, chloroplast editing, nanoparticle-mediated rapid chloroplast transformation, and horizontal gene transfer through grafting for targeting endogenous metabolic pathways for overproducing native nutraceuticals, production of biopharmaceuticals, and biosynthesis of designer nutritional compounds. This review focuses on exploring various features of chloroplast genome engineering for nutritional enhancement of food crops by enhancing the levels of existing metabolites, restoring the metabolites lost during crop domestication, and introducing novel metabolites and phytonutrients needed for a healthy daily diet.
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Affiliation(s)
- Neha Tanwar
- TERI-Deakin Nano-Biotechnology Centre, The Energy Resources Institute (TERI), New Delhi, India
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds Campus, Geelong, Australia
| | - Sagar S Arya
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds Campus, Geelong, Australia
| | - James E Rookes
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds Campus, Geelong, Australia
| | - David M Cahill
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds Campus, Geelong, Australia
| | - Sangram K Lenka
- TERI-Deakin Nano-Biotechnology Centre, The Energy Resources Institute (TERI), New Delhi, India
- Gujarat Biotechnology University, Gujarat, India
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4
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Taunt HN, Jackson HO, Gunnarsson ÍN, Pervaiz R, Purton S. Accelerating Chloroplast Engineering: A New System for Rapid Generation of Marker-Free Transplastomic Lines of Chlamydomonas reinhardtii. Microorganisms 2023; 11:1967. [PMID: 37630526 PMCID: PMC10457852 DOI: 10.3390/microorganisms11081967] [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: 06/08/2023] [Revised: 07/24/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023] Open
Abstract
'Marker-free' strategies for creating transgenic microorganisms avoid the issue of potential transmission of antibiotic resistance genes to other microorganisms. An already-established strategy for engineering the chloroplast genome (=plastome) of the green microalga Chlamydomonas reinhardtii involves the restoration of photosynthetic function using a recipient strain carrying a plastome mutation in a key photosynthesis gene. Selection for transformant colonies is carried out on minimal media, such that only those cells in which the mutated gene has been replaced with a wild-type copy carried on the transgenic DNA are capable of phototrophic growth. However, this approach can suffer from issues of efficiency due to the slow growth of C. reinhardtii on minimal media and the slow die-back of the untransformed lawn of cells when using mutant strains with a limited photosensitivity phenotype. Furthermore, such phototrophic rescue has tended to rely on existing mutants that are not necessarily ideal for transformation and targeted transgene insertion: Mutants carrying point mutations can easily revert, and those with deletions that do not extend to the intended transgene insertion site can give rise to a sub-population of rescued lines that lack the transgene. In order to improve and accelerate the transformation pipeline for C. reinhardtii, we have created a novel recipient line, HNT6, carrying an engineered deletion in exon 3 of psaA, which encodes one of the core subunits of photosystem I (PSI). Such PSI mutants are highly light-sensitive allowing faster recovery of transformant colonies by selecting for light-tolerance on acetate-containing media, rather than phototrophic growth on minimal media. The deletion extends to a site upstream of psaA-3 that serves as a neutral locus for transgene insertion, thereby ensuring that all of the recovered colonies are transformants containing the transgene. We demonstrate the application of HNT6 using a luciferase reporter.
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Affiliation(s)
- Henry N. Taunt
- Department of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Harry O. Jackson
- Department of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Ísarr N. Gunnarsson
- Department of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Rabbia Pervaiz
- Centre of Excellence in Molecular Biology, University of the Punjab, Lahore 53700, Pakistan
| | - Saul Purton
- Department of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
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5
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Charoonnart P, Taunt HN, Yang L, Webb C, Robinson C, Saksmerprome V, Purton S. Transgenic Microalgae Expressing Double-Stranded RNA as Potential Feed Supplements for Controlling White Spot Syndrome in Shrimp Aquaculture. Microorganisms 2023; 11:1893. [PMID: 37630453 PMCID: PMC10459155 DOI: 10.3390/microorganisms11081893] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 07/20/2023] [Accepted: 07/21/2023] [Indexed: 08/27/2023] Open
Abstract
Viral infection of farmed fish and shellfish represents a major issue within the aquaculture industry. One potential control strategy involves RNA interference of viral gene expression through the oral delivery of specific double-stranded RNA (dsRNA). In previous work, we have shown that recombinant dsRNA can be produced in the chloroplast of the edible microalga Chlamydomonas reinhardtii and used to control disease in shrimp. Here, we report a significant improvement in antiviral dsRNA production and its use to protect shrimp against white spot syndrome virus (WSSV). A new strategy for dsRNA synthesis was developed that uses two convergent copies of the endogenous rrnS promoter to drive high-level transcription of both strands of the WSSV gene element in the chloroplast. Quantitative RT-PCR indicated that ~119 ng dsRNA was produced per liter of culture of the transgenic microalga. This represents an ~10-fold increase in dsRNA relative to our previous report. The engineered alga was assessed for its ability to prevent WSSV infection when fed to shrimp larvae prior to a challenge with the virus. The survival of shrimp given feed supplemented with dried alga containing the dsRNA was significantly enhanced (~69% survival) relative to a negative control (<10% survival). The findings suggest that this new dsRNA production platform could be employed as a low-cost, low-tech control method for aquaculture.
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Affiliation(s)
- Patai Charoonnart
- Center of Excellence for Shrimp Molecular Biology and Biotechnology (Centex Shrimp), Faculty of Science, Mahidol University, Bangkok 10400, Thailand; (P.C.); (V.S.)
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathum Thani 12120, Thailand
| | - Henry Nicholas Taunt
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, UK
| | - Luyao Yang
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, UK
| | - Conner Webb
- Centre for Molecular Processing, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Colin Robinson
- Centre for Molecular Processing, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Vanvimon Saksmerprome
- Center of Excellence for Shrimp Molecular Biology and Biotechnology (Centex Shrimp), Faculty of Science, Mahidol University, Bangkok 10400, Thailand; (P.C.); (V.S.)
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathum Thani 12120, Thailand
| | - Saul Purton
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, UK
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6
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Di Rocco G, Taunt HN, Berto M, Jackson HO, Piccinini D, Carletti A, Scurani G, Braidi N, Purton S. A PETase enzyme synthesised in the chloroplast of the microalga Chlamydomonas reinhardtii is active against post-consumer plastics. Sci Rep 2023; 13:10028. [PMID: 37340047 DOI: 10.1038/s41598-023-37227-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 06/18/2023] [Indexed: 06/22/2023] Open
Abstract
Polyethylene terephthalate hydrolases (PETases) are a newly discovered and industrially important class of enzymes that catalyze the enzymatic degradation of polyethylene terephatalate (PET), one of the most abundant plastics in the world. The greater enzymatic efficiencies of PETases compared to close relatives from the cutinase and lipase families have resulted in increasing research interest. Despite this, further characterization of PETases is essential, particularly regarding their possible activity against other kinds of plastic. In this study, we exploited for the first time the use of the microalgal chloroplast for more sustainable synthesis of a PETase enzyme. A photosynthetic-restoration strategy was used to generate a marker-free transformant line of the green microalga Chlamydomonas reinhardtii in which the PETase from Ideonella sakaiensis was constitutively expressed in the chloroplast. Subsequently, the activity of the PETase against both PET and post-consumer plastics was investigated via atomic force microscopy, revealing evidence of degradation of the plastics.
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Affiliation(s)
- Giulia Di Rocco
- Department of Life Sciences, University of Modena and Reggio Emilia, 41125, Modena, Italy.
| | - Henry N Taunt
- Algal Research Group, Department of Structural and Molecular Biology, University College London, Gower Street, London, UK
| | - Marcello Berto
- Department of Life Sciences, University of Modena and Reggio Emilia, 41125, Modena, Italy
| | - Harry O Jackson
- Algal Research Group, Department of Structural and Molecular Biology, University College London, Gower Street, London, UK
| | - Daniele Piccinini
- Department of Life Sciences, University of Modena and Reggio Emilia, 41125, Modena, Italy
| | - Alan Carletti
- Department of Life Sciences, University of Modena and Reggio Emilia, 41125, Modena, Italy
| | - Giulia Scurani
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, 41125, Modena, Italy
| | - Niccolò Braidi
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, 41125, Modena, Italy
| | - Saul Purton
- Algal Research Group, Department of Structural and Molecular Biology, University College London, Gower Street, London, UK
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7
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Miró-Vinyals B, Artigues M, Wostrikoff K, Monte E, Broto-Puig F, Leivar P, Planas A. Chloroplast engineering of the green microalgae Chlamydomonas reinhardtii for the production of HAA, the lipid moiety of rhamnolipid biosurfactants. N Biotechnol 2023; 76:1-12. [PMID: 37004923 DOI: 10.1016/j.nbt.2023.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 02/25/2023] [Accepted: 03/30/2023] [Indexed: 04/03/2023]
Abstract
Hydroxyalkanoyloxyalkanoates (HAA) are lipidic surfactants with a number of potential applications, but more remarkably, they are the biosynthetic precursors of rhamnolipids (RL), which are preferred biosurfactants thanks to their excellent physicochemical properties, biological activities, and environmental biodegradability. Because the natural highest producer of RLs is the pathogenic bacterium Pseudomonas aeruginosa, important efforts have been dedicated to transfer production to heterologous non-pathogenic microorganisms. Unicellular photosynthetic microalgae are emerging as important hosts for sustainable industrial biotechnology due to their ability to transform CO2 efficiently into biomass and bioproducts of interest. Here, we have explored the potential of the eukaryotic green microalgae Chlamydomonas reinhardtii as a chassis to produce RLs. Chloroplast genome engineering allowed the stable functional expression of the gene encoding RhlA acyltransferase from P. aeruginosa, an enzyme catalyzing the condensation of two 3-hydroxyacyl acid intermediaries in the fatty acid synthase cycle, to produce HAA. Four congeners of varying chain lengths were identified and quantified by UHPLC-QTOF mass spectrometry and gas chromatography, including C10-C10 and C10-C8, and the less abundant C10-C12 and C10-C6 congeners. HAA was present in the intracellular fraction, but also showed increased accumulation in the extracellular medium. Moreover, HAA production was also observed under photoautotrophic conditions based on atmospheric CO2. These results establish that RhlA is active in the chloroplast and is able to produce a new pool of HAA in a eukaryotic host. Subsequent engineering of microalgal strains should contribute to the development of an alternative clean, safe and cost-effective platform for the sustainable production of RLs. DATA AVAILABILITY: The data that support the findings of this study are available from the corresponding authors upon reasonable request.
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8
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Jackson HO, Taunt HN, Mordaka PM, Kumari S, Smith AG, Purton S. CpPosNeg: A positive-negative selection strategy allowing multiple cycles of marker-free engineering of the Chlamydomonas plastome. Biotechnol J 2022; 17:e2200088. [PMID: 35509114 DOI: 10.1002/biot.202200088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/19/2022] [Accepted: 04/23/2022] [Indexed: 02/02/2023]
Abstract
The chloroplast represents an attractive compartment for light-driven biosynthesis of recombinant products, and advanced synthetic biology tools are available for engineering the chloroplast genome ( = plastome) of several algal and plant species. However, producing commercial lines will likely require several plastome manipulations. This presents issues with respect to selectable markers, since there are a limited number available, they can be used only once in a serial engineering strategy, and it is undesirable to retain marker genes for antibiotic resistance in the final transplastome. To address these problems, we have designed a rapid iterative selection system, known as CpPosNeg, for the green microalga Chlamydomonas reinhardtii that allows creation of marker-free transformants starting from wild-type strains. The system employs a dual marker encoding a fusion protein of E. coli aminoglycoside adenyltransferase (AadA: conferring spectinomycin resistance) and a variant of E. coli cytosine deaminase (CodA: conferring sensitivity to 5-fluorocytosine). Initial selection on spectinomycin allows stable transformants to be established and driven to homoplasmy. Subsequent selection on 5-fluorocytosine results in rapid loss of the dual marker through intramolecular recombination between the 3'UTR of the marker and the 3'UTR of the introduced transgene. We demonstrate the versatility of the CpPosNeg system by serial introduction of reporter genes into the plastome.
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Affiliation(s)
- Harry O Jackson
- Department of Structural and Molecular Biology, University College London, London, UK
| | - Henry N Taunt
- Department of Structural and Molecular Biology, University College London, London, UK
| | - Paweł M Mordaka
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Sujata Kumari
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, India
| | - Alison G Smith
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Saul Purton
- Department of Structural and Molecular Biology, University College London, London, UK
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9
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Suarez JV, Mudd EA, Day A. A Chloroplast-Localised Fluorescent Protein Enhances the Photosynthetic Action Spectrum in Green Algae. Microorganisms 2022; 10:microorganisms10091770. [PMID: 36144372 PMCID: PMC9504678 DOI: 10.3390/microorganisms10091770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/27/2022] [Accepted: 08/27/2022] [Indexed: 10/29/2022] Open
Abstract
Green microalgae are important sources of natural products and are attractive cell factories for manufacturing high-value products such as recombinant proteins. Increasing scales of production must address the bottleneck of providing sufficient light energy for photosynthesis. Enhancing the photosynthetic action spectrum of green algae to improve the utilisation of yellow light would provide additional light energy for photosynthesis. Here, we evaluated the Katushka fluorescent protein, which converts yellow photons to red photons, to drive photosynthesis and growth when expressed in Chlamydomonas reinhardtii chloroplasts. Transplastomic algae expressing a codon-optimised Katushka gene accumulated the active Katushka protein, which was detected by excitation with yellow light. Removal of chlorophyll from cells, which captures red photons, led to increased Katushka fluorescence. In yellow light, emission of red photons by fluorescent Katushka increased oxygen evolution and photosynthetic growth. Utilisation of yellow photons increased photosynthetic growth of transplastomic cells expressing Katushka in light deficient in red photons. These results showed that Katushka was a simple and effective yellow light-capturing device that enhanced the photosynthetic action spectrum of C. reinhardtii.
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Affiliation(s)
- Julio V. Suarez
- School of Biological Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
- Facultad de Ciencias, Universidad Autónoma de Baja California, Carr. Transpeninsular 3917, Ensenada 22860, Mexico
- Correspondence: (J.V.S.); (A.D.); Tel.: +44-161-275-3913 (A.D.)
| | - Elisabeth A. Mudd
- School of Biological Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Anil Day
- School of Biological Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
- Correspondence: (J.V.S.); (A.D.); Tel.: +44-161-275-3913 (A.D.)
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10
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Ma K, Deng L, Wu H, Fan J. Towards green biomanufacturing of high-value recombinant proteins using promising cell factory: Chlamydomonas reinhardtii chloroplast. BIORESOUR BIOPROCESS 2022; 9:83. [PMID: 38647750 PMCID: PMC10992328 DOI: 10.1186/s40643-022-00568-6] [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: 06/09/2022] [Accepted: 07/29/2022] [Indexed: 11/10/2022] Open
Abstract
Microalgae are cosmopolitan organisms in nature with short life cycles, playing a tremendous role in reducing the pressure of industrial carbon emissions. Besides, microalgae have the unique advantages of being photoautotrophic and harboring both prokaryotic and eukaryotic expression systems, becoming a popular host for recombinant proteins. Currently, numerous advanced molecular tools related to microalgal transgenesis have been explored and established, especially for the model species Chlamydomonas reinhardtii (C. reinhardtii hereafter). The development of genetic tools and the emergence of new strategies further increase the feasibility of developing C. reinhardtii chloroplasts as green factories, and the strong genetic operability of C. reinhardtii endows it with enormous potential as a synthetic biology platform. At present, C. reinhardtii chloroplasts could successfully produce plenty of recombinant proteins, including antigens, antibodies, antimicrobial peptides, protein hormones and enzymes. However, additional techniques and toolkits for chloroplasts need to be developed to achieve efficient and markerless editing of plastid genomes. Mining novel genetic elements and selectable markers will be more intensively studied in the future, and more factors affecting protein expression are urged to be explored. This review focuses on the latest technological progress of selectable markers for Chlamydomonas chloroplast genetic engineering and the factors that affect the efficiency of chloroplast protein expression. Furthermore, urgent challenges and prospects for future development are pointed out.
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Affiliation(s)
- Ke Ma
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China
| | - Lei Deng
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China
| | - Haizhen Wu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China.
- Department of Applied Biology, East China University of Science and Technology, Shanghai, 200237, People's Republic of China.
| | - Jianhua Fan
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China.
- Department of Applied Biology, East China University of Science and Technology, Shanghai, 200237, People's Republic of China.
- School of Chemistry and Chemical Engineering, Shihezi University, Shihezi, 832003, People's Republic of China.
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11
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Abstract
Multiple proof-of-principle experiments and successful field trials have demonstrated that engineering photosynthesis is a viable strategy for improving crop yields. Advances to engineering technologies have accelerated efforts to improve photosynthesis, generating a large volume of published literature: this Review therefore aims to highlight the most promising results from the period February 2021 to January 2022. Recent research has demonstrated the importance of understanding the impact of changing climates on photosynthesis to ensure that proposed engineering strategies are resilient to climate change. Encouragingly, there have been several reports of strategies that have benefits at temperatures higher than current ambient conditions. There has also been success in engineering synthetic bypass pathways, providing support for the feasibility of a synthetic biology approach. Continued developments in all areas of engineering photosynthesis will be necessary for sustainably securing sufficient crop yields for the future. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Sophie L Johnson
- Department of Plant Sciences, University of Oxford,Oxford, OX1 3RB,UK
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12
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Harnessing the Algal Chloroplast for Heterologous Protein Production. Microorganisms 2022; 10:microorganisms10040743. [PMID: 35456794 PMCID: PMC9025058 DOI: 10.3390/microorganisms10040743] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 03/24/2022] [Accepted: 03/28/2022] [Indexed: 02/04/2023] Open
Abstract
Photosynthetic microbes are gaining increasing attention as heterologous hosts for the light-driven, low-cost production of high-value recombinant proteins. Recent advances in the manipulation of unicellular algal genomes offer the opportunity to establish engineered strains as safe and viable alternatives to conventional heterotrophic expression systems, including for their use in the feed, food, and biopharmaceutical industries. Due to the relatively small size of their genomes, algal chloroplasts are excellent targets for synthetic biology approaches, and are convenient subcellular sites for the compartmentalized accumulation and storage of products. Different classes of recombinant proteins, including enzymes and peptides with therapeutical applications, have been successfully expressed in the plastid of the model organism Chlamydomonas reinhardtii, and of a few other species, highlighting the emerging potential of transplastomic algal biotechnology. In this review, we provide a unified view on the state-of-the-art tools that are available to introduce protein-encoding transgenes in microalgal plastids, and discuss the main (bio)technological bottlenecks that still need to be addressed to develop robust and sustainable green cell biofactories.
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Mapstone LJ, Leite MN, Purton S, Crawford IA, Dartnell L. Cyanobacteria and microalgae in supporting human habitation on Mars. Biotechnol Adv 2022; 59:107946. [DOI: 10.1016/j.biotechadv.2022.107946] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 02/21/2022] [Accepted: 03/15/2022] [Indexed: 12/16/2022]
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Larrea-Álvarez M, Purton S. The Chloroplast of Chlamydomonas reinhardtii as a Testbed for Engineering Nitrogen Fixation into Plants. Int J Mol Sci 2021; 22:8806. [PMID: 34445505 PMCID: PMC8395883 DOI: 10.3390/ijms22168806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 08/05/2021] [Accepted: 08/10/2021] [Indexed: 12/27/2022] Open
Abstract
Eukaryotic organisms such as plants are unable to utilise nitrogen gas (N2) directly as a source of this essential element and are dependent either on its biological conversion to ammonium by diazotrophic prokaryotes, or its supply as chemically synthesised nitrate fertiliser. The idea of genetically engineering crops with the capacity to fix N2 by introduction of the bacterial nitrogenase enzyme has long been discussed. However, the expression of an active nitrogenase must overcome several major challenges: the coordinated expression of multiple genes to assemble an enzyme complex containing several different metal cluster co-factors; the supply of sufficient ATP and reductant to the enzyme; the enzyme's sensitivity to oxygen; and the intracellular accumulation of ammonium. The chloroplast of plant cells represents an attractive location for nitrogenase expression, but engineering the organelle's genome is not yet feasible in most crop species. However, the unicellular green alga Chlamydomonas reinhardtii represents a simple model for photosynthetic eukaryotes with a genetically tractable chloroplast. In this review, we discuss the main advantages, and limitations, of this microalga as a testbed for producing such a complex multi-subunit enzyme. Furthermore, we suggest that a minimal set of six transgenes are necessary for chloroplast-localised synthesis of an 'Fe-only' nitrogenase, and from this set we demonstrate the stable expression and accumulation of the homocitrate synthase, NifV, under aerobic conditions. Arguably, further studies in C. reinhardtii aimed at testing expression and function of the full gene set would provide the groundwork for a concerted future effort to create nitrogen-fixing crops.
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Affiliation(s)
- Marco Larrea-Álvarez
- School of Biological Sciences and Engineering, Yachay-Tech University Hacienda San José, Urcuquí-Imbabura 100650, Ecuador;
- Algal Research Group, Department of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Saul Purton
- Algal Research Group, Department of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
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