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Kneip JS, Kniepkamp N, Jang J, Mortaro MG, Jin E, Kruse O, Baier T. CRISPR/Cas9-Mediated Knockout of the Lycopene ε-Cyclase for Efficient Astaxanthin Production in the Green Microalga Chlamydomonas reinhardtii. PLANTS (BASEL, SWITZERLAND) 2024; 13:1393. [PMID: 38794462 PMCID: PMC11125023 DOI: 10.3390/plants13101393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 05/09/2024] [Accepted: 05/09/2024] [Indexed: 05/26/2024]
Abstract
Carotenoids are valuable pigments naturally occurring in all photosynthetic plants and microalgae as well as in selected fungi, bacteria, and archaea. Green microalgae developed a complex carotenoid profile suitable for efficient light harvesting and light protection and harbor great capacity for carotenoid production through the substantial power of the endogenous 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway. Previous works established successful genome editing and induced significant changes in the cellular carotenoid content in Chlamydomonas reinhardtii. This study employs a tailored carotenoid pathway for engineered bioproduction of the valuable ketocarotenoid astaxanthin. Functional knockout of lycopene ε-cyclase (LCYE) and non-homologous end joining (NHEJ)-based integration of donor DNA at the target site inhibit the accumulation of α-carotene and consequently lutein and loroxanthin, abundant carotenoids in C. reinhardtii without changes in cellular fitness. PCR-based screening indicated that 4 of 96 regenerated candidate lines carried (partial) integrations of donor DNA and increased ß-carotene as well as derived carotenoid contents. Iterative overexpression of CrBKT, PacrtB, and CrCHYB resulted in a 2.3-fold increase in astaxanthin accumulation in mutant ΔLCYE#3 (1.8 mg/L) compared to the parental strain UVM4, which demonstrates the potential of genome editing for the design of a green cell factory for astaxanthin bioproduction.
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Affiliation(s)
- Jacob Sebastian Kneip
- Algae Biotechnology and Bioenergy, Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany
| | - Niklas Kniepkamp
- Algae Biotechnology and Bioenergy, Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany
| | - Junhwan Jang
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Maria Grazia Mortaro
- Algae Biotechnology and Bioenergy, Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany
| | - EonSeon Jin
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Olaf Kruse
- Algae Biotechnology and Bioenergy, Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany
| | - Thomas Baier
- Algae Biotechnology and Bioenergy, Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany
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2
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Chaux F, Jarrige D, Rodrigues-Azevedo M, Bujaldon S, Caspari OD, Ozawa SI, Drapier D, Vallon O, Choquet Y, de Vitry C. Chloroplast ATP synthase biogenesis requires peripheral stalk subunits AtpF and ATPG and stabilization of atpE mRNA by OPR protein MDE1. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 116:1582-1599. [PMID: 37824282 DOI: 10.1111/tpj.16448] [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: 05/17/2023] [Revised: 08/15/2023] [Accepted: 08/21/2023] [Indexed: 10/14/2023]
Abstract
Chloroplast ATP synthase contains subunits of plastid and nuclear genetic origin. To investigate the coordinated biogenesis of this complex, we isolated novel ATP synthase mutants in the green alga Chlamydomonas reinhardtii by screening for high light sensitivity. We report here the characterization of mutants affecting the two peripheral stalk subunits b and b', encoded respectively by the atpF and ATPG genes, and of three independent mutants which identify the nuclear factor MDE1, required to stabilize the chloroplast-encoded atpE mRNA. Whole-genome sequencing revealed a transposon insertion in the 3'UTR of ATPG while mass spectrometry shows a small accumulation of functional ATP synthase in this knock-down ATPG mutant. In contrast, knock-out ATPG mutants, obtained by CRISPR-Cas9 gene editing, fully prevent ATP synthase function and accumulation, as also observed in an atpF frame-shift mutant. Crossing ATP synthase mutants with the ftsh1-1 mutant of the major thylakoid protease identifies AtpH as an FTSH substrate, and shows that FTSH significantly contributes to the concerted accumulation of ATP synthase subunits. In mde1 mutants, the absence of atpE transcript fully prevents ATP synthase biogenesis and photosynthesis. Using chimeric atpE genes to rescue atpE transcript accumulation, we demonstrate that MDE1, a novel octotricopeptide repeat (OPR) protein, genetically targets the atpE 5'UTR. In the perspective of the primary endosymbiosis (~1.5 Gy), the recruitment of MDE1 to its atpE target exemplifies a nucleus/chloroplast interplay that evolved rather recently, in the ancestor of the CS clade of Chlorophyceae, ~300 My ago.
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Affiliation(s)
- Frédéric Chaux
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Domitille Jarrige
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Marcio Rodrigues-Azevedo
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Sandrine Bujaldon
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Oliver D Caspari
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Shin-Ichiro Ozawa
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Dominique Drapier
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Olivier Vallon
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Yves Choquet
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Catherine de Vitry
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
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3
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Milito A, Aschern M, McQuillan JL, Yang JS. Challenges and advances towards the rational design of microalgal synthetic promoters in Chlamydomonas reinhardtii. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:3833-3850. [PMID: 37025006 DOI: 10.1093/jxb/erad100] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 03/24/2023] [Indexed: 06/19/2023]
Abstract
Microalgae hold enormous potential to provide a safe and sustainable source of high-value compounds, acting as carbon-fixing biofactories that could help to mitigate rapidly progressing climate change. Bioengineering microalgal strains will be key to optimizing and modifying their metabolic outputs, and to render them competitive with established industrial biotechnology hosts, such as bacteria or yeast. To achieve this, precise and tuneable control over transgene expression will be essential, which would require the development and rational design of synthetic promoters as a key strategy. Among green microalgae, Chlamydomonas reinhardtii represents the reference species for bioengineering and synthetic biology; however, the repertoire of functional synthetic promoters for this species, and for microalgae generally, is limited in comparison to other commercial chassis, emphasizing the need to expand the current microalgal gene expression toolbox. Here, we discuss state-of-the-art promoter analyses, and highlight areas of research required to advance synthetic promoter development in C. reinhardtii. In particular, we exemplify high-throughput studies performed in other model systems that could be applicable to microalgae, and propose novel approaches to interrogating algal promoters. We lastly outline the major limitations hindering microalgal promoter development, while providing novel suggestions and perspectives for how to overcome them.
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Affiliation(s)
- Alfonsina Milito
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus UAB, Bellaterra, Barcelona, Spain
| | - Moritz Aschern
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus UAB, Bellaterra, Barcelona, Spain
| | - Josie L McQuillan
- Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK
| | - Jae-Seong Yang
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus UAB, Bellaterra, Barcelona, Spain
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4
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Perozeni F, Baier T. Current Nuclear Engineering Strategies in the Green Microalga Chlamydomonas reinhardtii. Life (Basel) 2023; 13:1566. [PMID: 37511941 PMCID: PMC10381326 DOI: 10.3390/life13071566] [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: 06/20/2023] [Revised: 07/07/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
The green model microalga Chlamydomonas reinhardtii recently emerged as a sustainable production chassis for the efficient biosynthesis of recombinant proteins and high-value metabolites. Its capacity for scalable, rapid and light-driven growth in minimal salt solutions, its simplicity for genetic manipulation and its "Generally Recognized As Safe" (GRAS) status are key features for its application in industrial biotechnology. Although nuclear transformation has typically resulted in limited transgene expression levels, recent developments now allow the design of powerful and innovative bioproduction concepts. In this review, we summarize the main obstacles to genetic engineering in C. reinhardtii and describe all essential aspects in sequence adaption and vector design to enable sufficient transgene expression from the nuclear genome. Several biotechnological examples of successful engineering serve as blueprints for the future establishment of C. reinhardtii as a green cell factory.
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Affiliation(s)
- Federico Perozeni
- Department of Biotechnology, University of Verona, 37134 Verona, Italy
| | - Thomas Baier
- Algae Biotechnology and Bioenergy, Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany
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Chen H, Yang QL, Xu JX, Deng X, Zhang YJ, Liu T, Rots MG, Xu GL, Huang KY. Efficient methods for multiple types of precise gene-editing in Chlamydomonas. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023. [PMID: 37310200 DOI: 10.1111/tpj.16265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 04/20/2023] [Accepted: 04/26/2023] [Indexed: 06/14/2023]
Abstract
Precise gene-editing using CRISPR/Cas9 technology remains a long-standing challenge, especially for genes with low expression and no selectable phenotypes in Chlamydomonas reinhardtii, a classic model for photosynthesis and cilia research. Here, we developed a multi-type and precise genetic manipulation method in which a DNA break was generated by Cas9 nuclease and the repair was mediated using a homologous DNA template. The efficacy of this method was demonstrated for several types of gene editing, including inactivation of two low-expression genes (CrTET1 and CrKU80), the introduction of a FLAG-HA epitope tag into VIPP1, IFT46, CrTET1 and CrKU80 genes, and placing a YFP tag into VIPP1 and IFT46 for live-cell imaging. We also successfully performed a single amino acid substitution for the FLA3, FLA10 and FTSY genes, and documented the attainment of the anticipated phenotypes. Lastly, we demonstrated that precise fragment deletion from the 3'-UTR of MAA7 and VIPP1 resulted in a stable knock-down effect. Overall, our study has established efficient methods for multiple types of precise gene editing in Chlamydomonas, enabling substitution, insertion and deletion at the base resolution, thus improving the potential of this alga in both basic research and industrial applications.
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Affiliation(s)
- Hui Chen
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Qing-Lin Yang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Jia-Xi Xu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xuan Deng
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Yun-Jie Zhang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Ting Liu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Marianne G Rots
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, 9713 GZ, Groningen, The Netherlands
| | - Guo-Liang Xu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
- Shanghai Key Laboratory of Medical Epigenetics, Laboratory of Cancer Epigenetics, Institutes of Biomedical Sciences, Medical College of Fudan University, Chinese Academy of Medical Sciences (RU069), Shanghai, China
| | - Kai-Yao Huang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
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6
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Jeong BR, Jang J, Jin E. Genome engineering via gene editing technologies in microalgae. BIORESOURCE TECHNOLOGY 2023; 373:128701. [PMID: 36746216 DOI: 10.1016/j.biortech.2023.128701] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 01/27/2023] [Accepted: 02/01/2023] [Indexed: 06/18/2023]
Abstract
CRISPR-Cas has revolutionized genetic modification with its comparative simplicity and accuracy, and it can be used even at the genomic level. Microalgae are excellent feedstocks for biofuels and nutraceuticals because they contain high levels of fatty acids, carotenoids, and other metabolites; however, genome engineering for microalgae is not yet as developed as for other model organisms. Microalgal engineering at the genetic and metabolic levels is relatively well established, and a few genomic resources are available. Their genomic information was used for a "safe harbor" site for stable transgene expression in microalgae. This review proposes further genome engineering schemes including the construction of sgRNA libraries, pan-genomic and epigenomic resources, and mini-genomes, which can together be developed into synthetic biology for carbon-based engineering in microalgae. Acetyl-CoA is at the center of carbon metabolic pathways and is further reviewed for the production of molecules including terpenoids in microalgae.
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Affiliation(s)
- Byeong-Ryool Jeong
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - Junhwan Jang
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - EonSeon Jin
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea; Hanyang Institute of Bioscience and Biotechnology, Hanyang University, Seoul 04763, Korea.
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7
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Belshaw N, Grouneva I, Aram L, Gal A, Hopes A, Mock T. Efficient gene replacement by CRISPR/Cas-mediated homologous recombination in the model diatom Thalassiosira pseudonana. THE NEW PHYTOLOGIST 2023; 238:438-452. [PMID: 36307966 DOI: 10.1111/nph.18587] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
CRISPR/Cas enables targeted genome editing in many different plant and algal species including the model diatom Thalassiosira pseudonana. However, efficient gene targeting by homologous recombination (HR) to date is only reported for photosynthetic organisms in their haploid life-cycle phase. Here, a CRISPR/Cas construct, assembled using Golden Gate cloning, enabled highly efficient HR in a diploid photosynthetic organism. Homologous recombination was induced in T. pseudonana using sequence-specific CRISPR/Cas, paired with a dsDNA donor matrix, generating substitution of the silacidin, nitrate reductase and urease genes by a resistance cassette (FCP:NAT). Up to c. 85% of NAT-resistant T. pseudonana colonies screened positive for HR by nested PCR. Precise integration of FCP:NAT at each locus was confirmed using an inverse PCR approach. The knockout of the nitrate reductase and urease genes impacted growth on nitrate and urea, respectively, while the knockout of the silacidin gene in T. pseudonana caused a significant increase in cell size, confirming the role of this gene for cell-size regulation in centric diatoms. Highly efficient gene targeting by HR makes T. pseudonana as genetically tractable as Nannochloropsis and Physcomitrella, hence rapidly advancing functional diatom biology, bionanotechnology and biotechnological applications targeted on harnessing the metabolic potential of diatoms.
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Affiliation(s)
- Nigel Belshaw
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Irina Grouneva
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Lior Aram
- Department of Plant and Environmental Sciences, Faculty of Biochemistry, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Assaf Gal
- Department of Plant and Environmental Sciences, Faculty of Biochemistry, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Amanda Hopes
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Thomas Mock
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
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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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The Spermidine Synthase Gene SPD1: A Novel Auxotrophic Marker for Chlamydomonas reinhardtii Designed by Enhanced CRISPR/Cas9 Gene Editing. Cells 2022; 11:cells11050837. [PMID: 35269459 PMCID: PMC8909627 DOI: 10.3390/cells11050837] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/15/2022] [Accepted: 02/24/2022] [Indexed: 01/09/2023] Open
Abstract
Biotechnological application of the green microalga Chlamydomonas reinhardtii hinges on the availability of selectable markers for effective expression of multiple transgenes. However, biological safety concerns limit the establishment of new antibiotic resistance genes and until today, only a few auxotrophic markers exist for C. reinhardtii. The recent improvements in gene editing via CRISPR/Cas allow directed exploration of new endogenous selectable markers. Since editing frequencies remain comparably low, a Cas9-sgRNA ribonucleoprotein (RNP) delivery protocol was strategically optimized by applying nitrogen starvation to the pre-culture, which improved successful gene edits from 10% to 66% after pre-selection. Probing the essential polyamine biosynthesis pathway, the spermidine synthase gene (SPD1) is shown to be a potent selectable marker with versatile biotechnological applicability. Very low levels of spermidine (0.75 mg/L) were required to maintain normal mixotrophic and phototrophic growth in newly designed spermidine auxotrophic strains. Complementation of these strains with a synthetic SPD1 gene was achieved when the mature protein was expressed in the cytosol or targeted to the chloroplast. This work highlights the potential of new selectable markers for biotechnology as well as basic research and proposes an effective pipeline for the identification of new auxotrophies in C. reinhardtii.
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Taparia Y, Dolui AK, Boussiba S, Khozin-Goldberg I. Multiplexed Genome Editing via an RNA Polymerase II Promoter-Driven sgRNA Array in the Diatom Phaeodactylum tricornutum: Insights Into the Role of StLDP. FRONTIERS IN PLANT SCIENCE 2022; 12:784780. [PMID: 35058949 PMCID: PMC8763850 DOI: 10.3389/fpls.2021.784780] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/29/2021] [Indexed: 06/14/2023]
Abstract
CRISPR/Cas9-mediated genome editing has been demonstrated in the model diatom P. tricornutum, yet the currently available genetic tools do not combine the various advantageous features into a single, easy-to-assemble, modular construct that would allow the multiplexed targeting and creation of marker-free genome-edited lines. In this report, we describe the construction of the first modular two-component transcriptional unit system expressing SpCas9 from a diatom episome, assembled using the Universal Loop plasmid kit for Golden Gate assembly. We compared the editing efficiency of two constructs with orthogonal promoter-terminator combinations targeting the StLDP gene, encoding the major lipid droplet protein of P. tricornutum. Multiplexed targeting of the StLDP gene was confirmed via PCR screening, and lines with homozygous deletions were isolated from primary exconjugants. An editing efficiency ranging from 6.7 to 13.8% was observed in the better performing construct. Selected gene-edited lines displayed growth impairment, altered morphology, and the formation of lipid droplets during nutrient-replete growth. Under nitrogen deprivation, oversized lipid droplets were observed; the recovery of cell proliferation and degradation of lipid droplets were impaired after nitrogen replenishment. The results are consistent with the key role played by StLDP in the regulation of lipid droplet size and lipid homeostasis.
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Affiliation(s)
| | | | | | - Inna Khozin-Goldberg
- Microalgal Biotechnology Laboratory, French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Sede Boqer, Israel
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11
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Schroda M, Remacle C. Molecular Advancements Establishing Chlamydomonas as a Host for Biotechnological Exploitation. FRONTIERS IN PLANT SCIENCE 2022; 13:911483. [PMID: 35845675 PMCID: PMC9277225 DOI: 10.3389/fpls.2022.911483] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 06/07/2022] [Indexed: 05/13/2023]
Abstract
Chlamydomonas reinhardtii is emerging as a production platform for biotechnological purposes thanks to recent achievements, which we briefly summarize in this review. Firstly, robust nuclear transgene expression is now possible because several impressive improvements have been made in recent years. Strains allowing efficient and stable nuclear transgene expression are available and were recently made more amenable to rational biotechnological approaches by enabling genetic crosses and identifying their causative mutation. The MoClo synthetic biology strategy, based on Golden Gate cloning, was developed for Chlamydomonas and includes a growing toolkit of more than 100 genetic parts that can be robustly and rapidly assembled in a predefined order. This allows for rapid iterative cycles of transgene design, building, testing, and learning. Another major advancement came from various findings improving transgene design and expression such as the systematic addition of introns into codon-optimized coding sequences. Lastly, the CRISPR/Cas9 technology for genome editing has undergone several improvements since its first successful report in 2016, which opens the possibility of optimizing biosynthetic pathways by switching off competing ones. We provide a few examples demonstrating that all these recent developments firmly establish Chlamydomonas as a chassis for synthetic biology and allow the rewiring of its metabolism to new capabilities.
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Affiliation(s)
- Michael Schroda
- Molecular Biotechnology and Systems Biology, TU Kaiserslautern, Kaiserslautern, Germany
| | - Claire Remacle
- Genetics and Physiology of Microalgae, InBios/Phytosystems Research Unit, University of Liege, Liege, Belgium
- *Correspondence: Claire Remacle,
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12
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Akella S, Ma X, Bacova R, Harmer ZP, Kolackova M, Wen X, Wright DA, Spalding MH, Weeks DP, Cerutti H. Co-targeting strategy for precise, scarless gene editing with CRISPR/Cas9 and donor ssODNs in Chlamydomonas. PLANT PHYSIOLOGY 2021; 187:2637-2655. [PMID: 34618092 PMCID: PMC8644747 DOI: 10.1093/plphys/kiab418] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/30/2021] [Indexed: 05/20/2023]
Abstract
Programmable site-specific nucleases, such as the clustered regularly interspaced short palindromic repeat (CRISPR)/ CRISPR-associated protein 9 (Cas9) ribonucleoproteins (RNPs), have allowed creation of valuable knockout mutations and targeted gene modifications in Chlamydomonas (Chlamydomonas reinhardtii). However, in walled strains, present methods for editing genes lacking a selectable phenotype involve co-transfection of RNPs and exogenous double-stranded DNA (dsDNA) encoding a selectable marker gene. Repair of the dsDNA breaks induced by the RNPs is usually accompanied by genomic insertion of exogenous dsDNA fragments, hindering the recovery of precise, scarless mutations in target genes of interest. Here, we tested whether co-targeting two genes by electroporation of pairs of CRISPR/Cas9 RNPs and single-stranded oligodeoxynucleotides (ssODNs) would facilitate the recovery of precise edits in a gene of interest (lacking a selectable phenotype) by selection for precise editing of another gene (creating a selectable marker)-in a process completely lacking exogenous dsDNA. We used PPX1 (encoding protoporphyrinogen IX oxidase) as the generated selectable marker, conferring resistance to oxyfluorfen, and identified precise edits in the homolog of bacterial ftsY or the WD and TetratriCopeptide repeats protein 1 genes in ∼1% of the oxyfluorfen resistant colonies. Analysis of the target site sequences in edited mutants suggested that ssODNs were used as templates for DNA synthesis during homology directed repair, a process prone to replicative errors. The Chlamydomonas acetolactate synthase gene could also be efficiently edited to serve as an alternative selectable marker. This transgene-free strategy may allow creation of individual strains containing precise mutations in multiple target genes, to study complex cellular processes, pathways, or structures.
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Affiliation(s)
- Soujanya Akella
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska–Lincoln, Lincoln, Nebraska 68588, USA
| | - Xinrong Ma
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska–Lincoln, Lincoln, Nebraska 68588, USA
| | - Romana Bacova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, CZ-613 00, Brno, Czech Republic
| | - Zachary P Harmer
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska–Lincoln, Lincoln, Nebraska 68588, USA
| | - Martina Kolackova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, CZ-613 00, Brno, Czech Republic
| | - Xiaoxue Wen
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska–Lincoln, Lincoln, Nebraska 68588, USA
| | - David A Wright
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011, USA
| | - Martin H Spalding
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011, USA
| | - Donald P Weeks
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Heriberto Cerutti
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska–Lincoln, Lincoln, Nebraska 68588, USA
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13
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Ferenczi A, Chew YP, Kroll E, von Koppenfels C, Hudson A, Molnar A. Mechanistic and genetic basis of single-strand templated repair at Cas12a-induced DNA breaks in Chlamydomonas reinhardtii. Nat Commun 2021; 12:6751. [PMID: 34799578 PMCID: PMC8604939 DOI: 10.1038/s41467-021-27004-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 10/26/2021] [Indexed: 12/12/2022] Open
Abstract
Single-stranded oligodeoxynucleotides (ssODNs) are widely used as DNA repair templates in CRISPR/Cas precision genome editing. However, the underlying mechanisms of single-strand templated DNA repair (SSTR) are inadequately understood, constraining rational improvements to precision editing. Here we study SSTR at CRISPR/Cas12a-induced DNA double-strand breaks (DSBs) in the eukaryotic model green microalga Chlamydomonas reinhardtii. We demonstrate that ssODNs physically incorporate into the genome during SSTR at Cas12a-induced DSBs. This process is genetically independent of the Rad51-dependent homologous recombination and Fanconi anemia pathways, is strongly antagonized by non-homologous end-joining, and is mediated almost entirely by the alternative end-joining enzyme polymerase θ. These findings suggest differences in SSTR between C. reinhardtii and animals. Our work illustrates the promising potentially of C. reinhardtii as a model organism for studying nuclear DNA repair.
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Affiliation(s)
- Aron Ferenczi
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Yen Peng Chew
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Erika Kroll
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
- Department of Biointeractions and Crop Protection, Rothamsted Research, Harpenden, AL5 2JQ, UK
| | | | - Andrew Hudson
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Attila Molnar
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK.
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14
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Sizova I, Kelterborn S, Verbenko V, Kateriya S, Hegemann P. Chlamydomonas POLQ is necessary for CRISPR/Cas9-mediated gene targeting. G3 (BETHESDA, MD.) 2021; 11:jkab114. [PMID: 33836052 PMCID: PMC8495919 DOI: 10.1093/g3journal/jkab114] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 03/18/2021] [Indexed: 02/06/2023]
Abstract
The use of CRISPR/Cas endonucleases has revolutionized gene editing techniques for research on Chlamydomonas reinhardtii. To better utilize the CRISPR/Cas system, it is essential to develop a more comprehensive understanding of the DNA repair pathways involved in genome editing. In this study, we have analyzed contributions from canonical KU80/KU70-dependent nonhomologous end-joining (cNHEJ) and DNA polymerase theta (POLQ)-mediated end joining on SpCas9-mediated untemplated mutagenesis and homology-directed repair (HDR)/gene inactivation in Chlamydomonas. Using CRISPR/SpCas9 technology, we generated DNA repair-defective mutants ku80, ku70, polQ for gene targeting experiments. Our results show that untemplated repair of SpCas9-induced double strand breaks results in mutation spectra consistent with an involvement of both KU80/KU70 and POLQ. In addition, the inactivation of POLQ was found to negatively affect HDR of the inactivated paromomycin-resistant mut-aphVIII gene when donor single-stranded oligos were used. Nevertheless, mut-aphVIII was still repaired by homologous recombination in these mutants. POLQ inactivation suppressed random integration of transgenes co-transformed with the donor ssDNA. KU80 deficiency did not affect these events but instead was surprisingly found to stimulate HDR/gene inactivation. Our data suggest that in Chlamydomonas, POLQ is the main contributor to CRISPR/Cas-induced HDR and random integration of transgenes, whereas KU80/KU70 potentially plays a secondary role. We expect our results will lead to improvement of genome editing in C. reinhardtii and can be used for future development of algal biotechnology.
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Affiliation(s)
- Irina Sizova
- Experimental Biophysics, Institute of Biology, Humboldt University of Berlin, Berlin D-10099, Germany
- Petersburg Nuclear Physics Institute named by B.P. Konstantinov of National Research Centre “Kurchatov Institute”, Gatchina 188300, Russia
- Kurchatov Genome Center - PNPI, Gatchina 188300, Russia
| | - Simon Kelterborn
- Experimental Biophysics, Institute of Biology, Humboldt University of Berlin, Berlin D-10099, Germany
| | - Valeriy Verbenko
- Petersburg Nuclear Physics Institute named by B.P. Konstantinov of National Research Centre “Kurchatov Institute”, Gatchina 188300, Russia
- Kurchatov Genome Center - PNPI, Gatchina 188300, Russia
| | - Suneel Kateriya
- Laboratory of Optobiology School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Peter Hegemann
- Experimental Biophysics, Institute of Biology, Humboldt University of Berlin, Berlin D-10099, Germany
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15
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Abu-Ghosh S, Dubinsky Z, Verdelho V, Iluz D. Unconventional high-value products from microalgae: A review. BIORESOURCE TECHNOLOGY 2021; 329:124895. [PMID: 33713898 DOI: 10.1016/j.biortech.2021.124895] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/18/2021] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
Microalgae have gained significant importance in biotechnology development, providing valuable goods and services in multiple applications. Although there is a rising market for most of these applications, the incorporation and introduction of microalgae into new venues will extend in the near future. These advances are due to the vast biodiversity of microalgal species, recent genetic engineering tools, and culture techniques. There are three main possible approaches for novel algal compounds from: (1) recently isolated yet less known microalgae; (2) selectively stressed conditions; and (3) enzymatically adjusted compounds from conventional molecules. All these approaches can be combined in a specific manner. This review discusses the opportunities, potential and limitations of introducing novel microalgae-based products, and how the recent technologies can be deployed to make these products financially viable. To give an outlook to the future, an analysis of the developments and predicted future market that further enlarge the promise of cultivating microalgae for commercial purposes are considered.
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Affiliation(s)
- Said Abu-Ghosh
- The Mina and Everard Goodman, Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
| | - Zvy Dubinsky
- The Mina and Everard Goodman, Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Vitor Verdelho
- General Manager of the European Algae Biomass Association (EABA), Portugal
| | - David Iluz
- The Mina and Everard Goodman, Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel; Department of Environmental Sciences and Agriculture, Beit Berl Academic College, Israel; Talpiot academic College, Holon, Israel
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16
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Guardini Z, Dall’Osto L, Barera S, Jaberi M, Cazzaniga S, Vitulo N, Bassi R. High Carotenoid Mutants of Chlorella vulgaris Show Enhanced Biomass Yield under High Irradiance. PLANTS 2021; 10:plants10050911. [PMID: 34062906 PMCID: PMC8147269 DOI: 10.3390/plants10050911] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 12/30/2022]
Abstract
Microalgae represent a carbon-neutral source of bulk biomass, for extraction of high-value compounds and production of renewable fuels. Due to their high metabolic activity and reproduction rates, species of the genus Chlorella are highly productive when cultivated in photobioreactors. However, wild-type strains show biological limitations making algal bioproducts expensive compared to those extracted from other feedstocks. Such constraints include inhomogeneous light distribution due to high optical density of the culture, and photoinhibition of the surface-exposed cells. Thus, the domestication of algal strains for industry makes it increasingly important to select traits aimed at enhancing light-use efficiency while withstanding excess light stress. Carotenoids have a crucial role in protecting against photooxidative damage and, thus, represent a promising target for algal domestication. We applied chemical mutagenesis to Chlorella vulgaris and selected for enhanced tolerance to the carotenoid biosynthesis inhibitor norflurazon. The NFR (norflurazon-resistant) strains showed an increased carotenoid pool size and enhanced tolerance towards photooxidative stress. Growth under excess light revealed an improved carbon assimilation rate of NFR strains with respect to WT. We conclude that domestication of Chlorella vulgaris, by optimizing both carotenoid/chlorophyll ratio and resistance to photooxidative stress, boosted light-to-biomass conversion efficiency under high light conditions typical of photobioreactors. Comparison with strains previously reported for enhanced tolerance to singlet oxygen, reveals that ROS resistance in Chlorella is promoted by at least two independent mechanisms, only one of which is carotenoid-dependent.
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17
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Gutiérrez S, Lauersen KJ. Gene Delivery Technologies with Applications in Microalgal Genetic Engineering. BIOLOGY 2021; 10:265. [PMID: 33810286 PMCID: PMC8067306 DOI: 10.3390/biology10040265] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/18/2021] [Accepted: 03/24/2021] [Indexed: 12/28/2022]
Abstract
Microalgae and cyanobacteria are photosynthetic microbes that can be grown with the simple inputs of water, carbon dioxide, (sun)light, and trace elements. Their engineering holds the promise of tailored bio-molecule production using sustainable, environmentally friendly waste carbon inputs. Although algal engineering examples are beginning to show maturity, severe limitations remain in the transformation of multigene expression cassettes into model species and DNA delivery into non-model hosts. This review highlights common and emerging DNA delivery methods used for other organisms that may find future applications in algal engineering.
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Affiliation(s)
| | - Kyle J. Lauersen
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia;
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