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Zhao J, Ge Y, Liu K, Yamaoka Y, Zhang D, Chi Z, Akkaya M, Kong F. Overexpression of a MYB1 Transcription Factor Enhances Triacylglycerol and Starch Accumulation and Biomass Production in the Green Microalga Chlamydomonas reinhardtii. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:17833-17841. [PMID: 37934701 DOI: 10.1021/acs.jafc.3c05290] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
Microalgae are promising platforms for biofuel production. Transcription factors (TFs) are emerging as key regulators of lipid metabolism for biofuel production in microalgae. We previously identified a novel TF MYB1, which mediates lipid accumulation in the green microalga Chlamydomonas under nitrogen depletion. However, the function of MYB1 on lipid metabolism in microalgae under standard growth conditions remains poorly understood. Here, we examined the effects of MYB1 overexpression (MYB1-OE) on lipid metabolism and physiological changes in Chlamydomonas. Under standard growth conditions, MYB1-OE transformants accumulated 1.9 to 3.2-fold more triacylglycerols (TAGs) than that in the parental line (PL), and total fatty acids (FAs) also significantly increased. Moreover, saturated FA (C16:0) was enriched in TAGs and total FAs in MYB1-OE transformants. Notably, starch and protein content and biomass production also significantly increased in MYB1-OE transformants compared with that in PL. Furthermore, RT-qPCR results showed that the expressions of key genes involved in TAG, FA, and starch biosynthesis were upregulated. In addition, MYB1-OE transformants showed higher biomass production without a compromised cell growth rate and photosynthetic activity. Overall, our results indicate that MYB1 overexpression not only enhanced lipid content but also improved starch and protein content and biomass production under standard growth conditions. TF MYB1 engineering is a promising genetic engineering tool for biofuel production in microalgae.
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Affiliation(s)
- Jilong Zhao
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China
| | - Yunlong Ge
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China
| | - Keqing Liu
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China
| | - Yasuyo Yamaoka
- Division of Biotechnology, The Catholic University of Korea, Bucheon 14662, Korea
| | - Di Zhang
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China
| | - Zhanyou Chi
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China
| | - Mahinur Akkaya
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China
| | - Fantao Kong
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China
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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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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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Pervaiz R, Khan MA, Raza FA, Ahmad S, Zafar AU, Ahmed N, Akram M. Expression of a mosquito larvicidal gene in chloroplast and nuclear compartments of Chlamydomonas reinhardtii. J Biotechnol 2022; 360:182-191. [PMID: 36368638 DOI: 10.1016/j.jbiotec.2022.11.004] [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: 05/19/2022] [Revised: 11/01/2022] [Accepted: 11/07/2022] [Indexed: 11/09/2022]
Abstract
As a part of the search for environment-friendly biocontrol of mosquito-borne diseases, mosquito larvicidal potential of Bacillus thuringiensis subsp. jegathesan (Btj) Cry toxins is explored for toxins with increased toxicity. Safe delivery of the Cry toxins to mosquito larvae in aquatic habitats is a major concern. This is because in water bodies Bacillus thuringiensis (Bt) protein formulations degrade by sunlight, can sink down and get adsorbed by the silt. So, because of its short persistence the toxin requires repeated applications at the given site. Therefore, an upcoming approach is incorporating the Bt toxins in Chlamydomonas reinhardtii (C. reinhardtii) because it is a food of mosquito larvae in water and its molecular toolkit is well investigated for foreign gene expression. The present work aimed to compare the feasibility of C. reinhardtii chloroplast and nuclear compartments for stable expression of Cry11Ba toxin as this is the most toxic Btj protein to date, lethal to different mosquito species. With chloroplast expression of cry11Ba gene we were able to generate marker-free C. reinhardtii strain stably expressing Cry11Ba protein and demonstrating mortality against Aedes aegypti larvae. Moreover, for nuclear expression linking the cry11Ba gene to zeocin via foot and mouth disease virus (FMDV) 2A peptide resulted in the selection of transformants with increased cry11Ba mRNA expression levels by semi-quantitative reverse transcriptase PCR. Obtained results lay a foundation for the C. reinhardtii chloroplast expression system to be used for genetic engineering with Bt toxins which possess enhanced toxicity.
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Affiliation(s)
- Rabbia Pervaiz
- Centre of Excellence in Molecular Biology, University of the Punjab, 87-West Canal Road, Thokar Niaz Baig Sector-1, Lahore 53700, Pakistan.
| | - Mohsin Ahmad Khan
- Centre of Excellence in Molecular Biology, University of the Punjab, 87-West Canal Road, Thokar Niaz Baig Sector-1, Lahore 53700, Pakistan
| | - Faiz Ahmed Raza
- Health Research Institute, National Institute of Health (HRI-NIH), Research Centre, King Edward Medical University, Lahore 54000, Pakistan
| | - Sohail Ahmad
- Centre of Excellence in Molecular Biology, University of the Punjab, 87-West Canal Road, Thokar Niaz Baig Sector-1, Lahore 53700, Pakistan
| | - Ahmad Usman Zafar
- Qarshi University, 8-Km Thokar Niaz Baig, Canal Bank Road, Opposite Izmir Town, Lahore 54000, Pakistan
| | - Nadeem Ahmed
- Centre of Excellence in Molecular Biology, University of the Punjab, 87-West Canal Road, Thokar Niaz Baig Sector-1, Lahore 53700, Pakistan
| | - Maham Akram
- Centre of Excellence in Molecular Biology, University of the Punjab, 87-West Canal Road, Thokar Niaz Baig Sector-1, Lahore 53700, Pakistan
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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: 4] [Impact Index Per Article: 2.0] [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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6
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Singh M, Mal N, Mohapatra R, Bagchi T, Parambath SD, Chavali M, Rao KM, Ramanaiah SV, Kadier A, Kumar G, Chandrasekhar K, Kim SH. Recent biotechnological developments in reshaping the microalgal genome: A signal for green recovery in biorefinery practices. CHEMOSPHERE 2022; 293:133513. [PMID: 34990720 DOI: 10.1016/j.chemosphere.2022.133513] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 12/13/2021] [Accepted: 12/31/2021] [Indexed: 06/14/2023]
Abstract
The use of renewable energy sources as a substitute for nonrenewable fossil fuels is urgently required. Algae biorefinery platform provides an excellent alternate to overcome future energy problems. However, to let this viable biomass be competent with existing feedstocks, it is necessary to exploit genetic manipulation and improvement in upstream and downstream platforms for optimal bio-product recovery. Furthermore, the techno-economic strategies further maximize metabolites production for biofuel, biohydrogen, and other industrial applications. The experimental methodologies in algal photobioreactor promote high biomass production, enriched in lipid and starch content in limited environmental conditions. This review presents an optimization framework combining genetic manipulation methods to simulate microalgal growth dynamics, understand the complexity of algal biorefinery to scale up, and identify green strategies for techno-economic feasibility of algae for biomass conversion. Overall, the algal biorefinery opens up new possibilities for the valorization of algae biomass and the synthesis of various novel products.
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Affiliation(s)
- Meenakshi Singh
- Department of Botany, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara, 390002, Gujarat, India
| | - Navonil Mal
- Department of Botany, University of Calcutta, Kolkata, 700019, West Bengal, India
| | - Reecha Mohapatra
- Department of Life Sciences, NIT Rourkela, 769008, Odisha, India
| | - Trisha Bagchi
- Department of Botany, West Bengal State University, Barasat, 700126, West Bengal, India
| | | | - Murthy Chavali
- Office of the Dean (Research) & Division of Chemistry, Department of Science, Faculty of Science & Technology, Alliance University (Central Campus), Chandapura-Anekal Main Road, Bengaluru, 562106, Karnataka, India; NTRC-MCETRC and 109 Nano Composite Technologies Pvt. Ltd., Guntur District, 522201, Andhra Pradesh, India
| | - Kummara Madhusudana Rao
- School of Chemical Engineering, Yeungnam University, 280 Daehak-ro, Joyeong-dong, Gyeongsan-si, Gyeongsangbuk-do, 38541, South Korea; Department of Automotive Lighting Convergence Engineering, Yeungnam University, 280 Daehak-ro, Joyeong-dong, Gyeongsan-si, Gyeongsangbuk-do, 38541, South Korea
| | - S V Ramanaiah
- Food and Biotechnology Research Lab, South Ural State University (National Research University), 454080, Chelyabinsk, Russian Federation
| | - Abudukeremu Kadier
- Laboratory of Environmental Science and Technology, The Xinjiang Technical Institute of Physics and Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi, 830011, China; Center of Material and Opto-electronic Research, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Gopalakrishnan Kumar
- Institute of Chemistry, Bioscience and Environmental Engineering, Faculty of Science and Technology, University of Stavanger, 4036, Stavanger, Norway
| | - K Chandrasekhar
- School of Civil and Environmental Engineering, Yonsei University, Seoul, 03722, Republic of Korea.
| | - Sang-Hyoun Kim
- School of Civil and Environmental Engineering, Yonsei University, Seoul, 03722, Republic of Korea.
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Expression of Anti-Lipopolysaccharide Factor Isoform 3 in Chlamydomonas reinhardtii Showing High Antimicrobial Activity. Mar Drugs 2021; 19:md19050239. [PMID: 33922554 PMCID: PMC8146899 DOI: 10.3390/md19050239] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/20/2021] [Accepted: 04/20/2021] [Indexed: 01/10/2023] Open
Abstract
Antimicrobial peptides are a class of proteins with antibacterial functions. In this study, the anti-lipopolysaccharide factor isoform 3 gene (ALFPm3), encoding an antimicrobial peptide from Penaeus monodon with a super activity was expressed in Chlamydomonas reinhardtii, which would develop a microalga strain that can be used for the antimicrobial peptide production. To construct the expression cluster, namely pH2A-Pm3, the codon optimized ALFPm3 gene was fused with the ble reporter by 2A peptide and inserted into pH124 vector. The glass-bead method was performed to transform pH2A-Pm3 into C. reinhardtii CC-849. In addition to 8 μg/mL zeocin resistance selection, the C. reinhardtii transformants were further confirmed by genomic PCR and RT-PCR. Western blot analysis showed that the C. reinhardtii-derived ALFPm3 (cALFPm3) was successfully expressed in C. reinhardtii transformants and accounted for 0.35% of the total soluble protein (TSP). Furthermore, the results of antibacterial assay revealed that the cALFPm3 could significantly inhibit the growth of a variety of bacteria, including both Gram-negative bacteria and Gram-positive bacteria at a concentration of 0.77 μM. Especially, the inhibition could last longer than 24 h, which performed better than ampicillin. Hence, this study successfully developed a transgenic C. reinhardtii strain, which can produce the active ALFPm3 driven from P. monodon, providing a potential strategy to use C. reinhardtii as the cell factory to produce antimicrobial peptides.
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Benedetti M, Barera S, Longoni P, Guardini Z, Herrero Garcia N, Bolzonella D, Lopez‐Arredondo D, Herrera‐Estrella L, Goldschmidt‐Clermont M, Bassi R, Dall’Osto L. A microalgal-based preparation with synergistic cellulolytic and detoxifying action towards chemical-treated lignocellulose. PLANT BIOTECHNOLOGY JOURNAL 2021; 19:124-137. [PMID: 32649019 PMCID: PMC7769238 DOI: 10.1111/pbi.13447] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 06/19/2020] [Accepted: 06/28/2020] [Indexed: 05/28/2023]
Abstract
High-temperature bioconversion of lignocellulose into fermentable sugars has drawn attention for efficient production of renewable chemicals and biofuels, because competing microbial activities are inhibited at elevated temperatures and thermostable cell wall degrading enzymes are superior to mesophilic enzymes. Here, we report on the development of a platform to produce four different thermostable cell wall degrading enzymes in the chloroplast of Chlamydomonas reinhardtii. The enzyme blend was composed of the cellobiohydrolase CBM3GH5 from C. saccharolyticus, the β-glucosidase celB from P. furiosus, the endoglucanase B and the endoxylanase XynA from T. neapolitana. In addition, transplastomic microalgae were engineered for the expression of phosphite dehydrogenase D from Pseudomonas stutzeri, allowing for growth in non-axenic media by selective phosphite nutrition. The cellulolytic blend composed of the glycoside hydrolase (GH) domain GH12/GH5/GH1 allowed the conversion of alkaline-treated lignocellulose into glucose with efficiencies ranging from 14% to 17% upon 48h of reaction and an enzyme loading of 0.05% (w/w). Hydrolysates from treated cellulosic materials with extracts of transgenic microalgae boosted both the biogas production by methanogenic bacteria and the mixotrophic growth of the oleaginous microalga Chlorella vulgaris. Notably, microalgal treatment suppressed the detrimental effect of inhibitory by-products released from the alkaline treatment of biomass, thus allowing for efficient assimilation of lignocellulose-derived sugars by C. vulgaris under mixotrophic growth.
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Affiliation(s)
- Manuel Benedetti
- Dipartimento di BiotecnologieUniversità di VeronaVeronaItaly
- Present address:
Dipartimento MESVAUniversità dell'AquilaCoppitoAQItaly
| | - Simone Barera
- Dipartimento di BiotecnologieUniversità di VeronaVeronaItaly
| | - Paolo Longoni
- Faculty of ScienceInstitute of BiologyUniversity of NeuchâtelNeuchâtelSwitzerland
| | - Zeno Guardini
- Dipartimento di BiotecnologieUniversità di VeronaVeronaItaly
| | | | | | - Damar Lopez‐Arredondo
- StelaGenomics MexicoS de RL de CVIrapuato, GuanajuatoMexico
- Institute of Genomics for Crop Abiotic Stress ToleranceTexas Tech UniversityLubbockTXUSA
| | - Luis Herrera‐Estrella
- Laboratorio Nacional de Genómica para la BiodiversidadCentro de Investigación y de Estudios Avanzados del Instituto Politécnico NacionalIrapuato, GuanajuatoMexico
- Institute of Genomics for Crop Abiotic Stress ToleranceTexas Tech UniversityLubbockTXUSA
| | | | - Roberto Bassi
- Dipartimento di BiotecnologieUniversità di VeronaVeronaItaly
| | - Luca Dall’Osto
- Dipartimento di BiotecnologieUniversità di VeronaVeronaItaly
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Jackson HO, Taunt HN, Mordaka PM, Smith AG, Purton S. The Algal Chloroplast as a Testbed for Synthetic Biology Designs Aimed at Radically Rewiring Plant Metabolism. FRONTIERS IN PLANT SCIENCE 2021; 12:708370. [PMID: 34630459 PMCID: PMC8497815 DOI: 10.3389/fpls.2021.708370] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 08/10/2021] [Indexed: 05/04/2023]
Abstract
Sustainable and economically viable support for an ever-increasing global population requires a paradigm shift in agricultural productivity, including the application of biotechnology to generate future crop plants. Current genetic engineering approaches aimed at enhancing the photosynthetic efficiency or composition of the harvested tissues involve relatively simple manipulations of endogenous metabolism. However, radical rewiring of central metabolism using new-to-nature pathways, so-called "synthetic metabolism", may be needed to really bring about significant step changes. In many cases, this will require re-programming the metabolism of the chloroplast, or other plastids in non-green tissues, through a combination of chloroplast and nuclear engineering. However, current technologies for sophisticated chloroplast engineering ("transplastomics") of plants are limited to just a handful of species. Moreover, the testing of metabolic rewiring in the chloroplast of plant models is often impractical given their obligate phototrophy, the extended time needed to create stable non-chimeric transplastomic lines, and the technical challenges associated with regeneration of whole plants. In contrast, the unicellular green alga, Chlamydomonas reinhardtii is a facultative heterotroph that allows for extensive modification of chloroplast function, including non-photosynthetic designs. Moreover, chloroplast engineering in C. reinhardtii is facile, with the ability to generate novel lines in a matter of weeks, and a well-defined molecular toolbox allows for rapid iterations of the "Design-Build-Test-Learn" (DBTL) cycle of modern synthetic biology approaches. The recent development of combinatorial DNA assembly pipelines for designing and building transgene clusters, simple methods for marker-free delivery of these clusters into the chloroplast genome, and the pre-existing wealth of knowledge regarding chloroplast gene expression and regulation in C. reinhardtii further adds to the versatility of transplastomics using this organism. Herein, we review the inherent advantages of the algal chloroplast as a simple and tractable testbed for metabolic engineering designs, which could then be implemented in higher plants.
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Affiliation(s)
- Harry O. Jackson
- Department of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Henry N. Taunt
- Department of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Pawel M. Mordaka
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Alison G. Smith
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Saul Purton
- Department of Structural and Molecular Biology, University College London, London, United Kingdom
- *Correspondence: Saul Purton
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Larrea-Alvarez M, Purton S. Multigenic engineering of the chloroplast genome in the green alga Chlamydomonas reinhardtii. MICROBIOLOGY (READING, ENGLAND) 2020; 166:510-515. [PMID: 32250732 PMCID: PMC7376270 DOI: 10.1099/mic.0.000910] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 03/11/2020] [Indexed: 12/25/2022]
Abstract
The chloroplast of microalgae such as Chlamydomonas reinhardtii represents an attractive chassis for light-driven production of novel recombinant proteins and metabolites. Methods for the introduction and expression of transgenes in the chloroplast genome (=plastome) of C. reinhardtii are well-established and over 100 different proteins have been successfully produced. However, in almost all reported cases the complexity of the genetic engineering is low, and typically involves introduction into the plastome of just a single transgene together with a selectable marker. In order to exploit fully the potential of the algal chassis it is necessary to establish methods for multigenic engineering in which many transgenes can be stably incorporated into the plastome. This would allow the synthesis of multi-subunit proteins and the introduction into the chloroplast of whole new metabolic pathways. In this short communication we report a proof-of-concept study involving both a combinatorial and serial approach, with the goal of synthesizing five different test proteins in the C. reinhardtii chloroplast. Analysis of the various transgenic lines confirmed the successful integration of the transgenes and accumulation of the gene products. However, the work also highlights an issue of genetic instability when using the same untranslated region for each of the transgenes. Our findings therefore help to define appropriate strategies for robust multigenic engineering of the algal chloroplast.
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Affiliation(s)
- Marco Larrea-Alvarez
- Algal Research Group, Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK
- Present address: School of Biological Sciences and Engineering. Yachay-Tech University Hacienda San José, Urcuquí-Imbabura, Ecuador
| | - Saul Purton
- Algal Research Group, Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK
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Hsu SC, Browne DR, Tatli M, Devarenne TP, Stern DB. N-terminal sequences affect expression of triterpene biosynthesis enzymes in Chlamydomonas chloroplasts. ALGAL RES 2019. [DOI: 10.1016/j.algal.2019.101662] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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12
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Dineshbabu G, Goswami G, Kumar R, Sinha A, Das D. Microalgae–nutritious, sustainable aqua- and animal feed source. J Funct Foods 2019. [DOI: 10.1016/j.jff.2019.103545] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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13
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Kwon YM, Kim KW, Choi TY, Kim SY, Kim JYH. Manipulation of the microalgal chloroplast by genetic engineering for biotechnological utilization as a green biofactory. World J Microbiol Biotechnol 2018; 34:183. [PMID: 30478596 DOI: 10.1007/s11274-018-2567-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 11/23/2018] [Indexed: 12/16/2022]
Abstract
The chloroplast is an essential organelle in microalgae for conducting photosynthesis, thus enabling the photoautotrophic growth of microalgae. In addition to photosynthesis, the chloroplast is capable of various biochemical processes for the synthesis of proteins, lipids, carbohydrates, and terpenoids. Due to these attractive characteristics, there has been increasing interest in the biotechnological utilization of microalgal chloroplast as a sustainable alternative to the conventional production platforms used in industrial biotechnology. Since the first demonstration of microalgal chloroplast transformation, significant development has occurred over recent decades in the manipulation of microalgal chloroplasts through genetic engineering. In the present review, we describe the advantages of the microalgal chloroplast as a production platform for various bioproducts, including recombinant proteins and high-value metabolites, features of chloroplast genetic systems, and the development of transformation methods, which represent important factors for gene expression in the chloroplast. Furthermore, we address the expression of various recombinant proteins in the microalgal chloroplast through genetic engineering, including reporters, biopharmaceutical proteins, and industrial enzymes. Finally, we present many efforts and achievements in the production of high-value metabolites in the microalgal chloroplast through metabolic engineering. Based on these efforts and advances, the microalgal chloroplast represents an economically viable and sustainable platform for biotechnological applications in the near future.
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Affiliation(s)
- Yong Min Kwon
- Department of Applied Research, National Marine Biodiversity Institute of Korea, Jangsan-ro 101-75, Seocheon, Chungcheongnamdo, 33662, Republic of Korea
| | - Kyung Woo Kim
- Department of Applied Research, National Marine Biodiversity Institute of Korea, Jangsan-ro 101-75, Seocheon, Chungcheongnamdo, 33662, Republic of Korea
| | - Tae-Young Choi
- Department of Genetic Resources Research, National Marine Biodiversity Institute of Korea, Jangsan-ro 101-75, Seocheon, Chungcheongnamdo, 33662, Republic of Korea
| | - Sun Young Kim
- Department of Applied Research, National Marine Biodiversity Institute of Korea, Jangsan-ro 101-75, Seocheon, Chungcheongnamdo, 33662, Republic of Korea
| | - Jaoon Young Hwan Kim
- Department of Applied Research, National Marine Biodiversity Institute of Korea, Jangsan-ro 101-75, Seocheon, Chungcheongnamdo, 33662, Republic of Korea.
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14
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Esland L, Larrea-Alvarez M, Purton S. Selectable Markers and Reporter Genes for Engineering the Chloroplast of Chlamydomonas reinhardtii. BIOLOGY 2018; 7:E46. [PMID: 30309004 PMCID: PMC6315944 DOI: 10.3390/biology7040046] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/02/2018] [Accepted: 10/03/2018] [Indexed: 02/07/2023]
Abstract
Chlamydomonas reinhardtii is a model alga of increasing interest as a cell factory for the production of valuable compounds, including therapeutic proteins and bioactive metabolites. Expression of foreign genes in the chloroplast is particularly advantageous as: (i) accumulation of product in this sub-cellular compartment minimises potential toxicity to the rest of the cell; (ii) genes can integrate at specific loci of the chloroplast genome (plastome) by homologous recombination; (iii) the high ploidy of the plastome and the high-level expression of chloroplast genes can be exploited to achieve levels of recombinant protein as high as 5% total cell protein; (iv) the lack of any gene silencing mechanisms in the chloroplast ensures stable expression of transgenes. However, the generation of C. reinhardtii chloroplast transformants requires efficient methods of selection, and ideally methods for subsequent marker removal. Additionally, the use of reporter genes is critical to achieving a comprehensive understanding of gene expression, thereby informing experimental design for recombinant applications. This review discusses currently available selection and reporter systems for chloroplast engineering in C. reinhardtii, as well as those used for chloroplast engineering in higher plants and other microalgae, and looks to the future in terms of possible new markers and reporters that will further advance the C. reinhardtii chloroplast as an expression platform.
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Affiliation(s)
- Lola Esland
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
| | - Marco Larrea-Alvarez
- School of Biological Sciences and Engineering, Yachay-Tech University, Hacienda San José, Urcuquí-Imbabura 100650, Ecuador.
| | - Saul Purton
- Institute of Structural & Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK.
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15
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Over-accumulation of astaxanthin in Haematococcus pluvialis through chloroplast genetic engineering. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.02.024] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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16
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Dyo YM, Purton S. The algal chloroplast as a synthetic biology platform for production of therapeutic proteins. Microbiology (Reading) 2018; 164:113-121. [DOI: 10.1099/mic.0.000599] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Yuliya M. Dyo
- Molecular Research of Microalgae Laboratory, M. A. Ajtkhozhin Institute of Molecular Biology and Biochemistry, Almaty, Kazakhstan
- Department of Biotechnology, Kazakh National Research Technology University, Almaty, Kazakhstan
| | - Saul Purton
- Algal Research Group, Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK
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17
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Taunt HN, Stoffels L, Purton S. Green biologics: The algal chloroplast as a platform for making biopharmaceuticals. Bioengineered 2017; 9:48-54. [PMID: 28892417 PMCID: PMC5972929 DOI: 10.1080/21655979.2017.1377867] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Most commercial production of recombinant pharmaceutical proteins involves the use of mammalian cell lines, E. coli or yeast as the expression host. However, recent work has demonstrated the potential of eukaryotic microalgae as platforms for light-driven synthesis of such proteins. Expression in the algal chloroplast is particularly attractive since this organelle contains a minimal genome suitable for rapid engineering using synthetic biology approaches; with transgenes precisely targeted to specific genomic loci and amenable to high-level, regulated and stable expression. Furthermore, proteins can be tightly contained and bio-encapsulated in the chloroplast allowing accumulation of proteins otherwise toxic to the host, and opening up possibilities for low-cost, oral delivery of biologics. In this commentary we illustrate the technology with recent examples of hormones, protein antibiotics and immunotoxins successfully produced in the algal chloroplast, and highlight possible future applications.
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Affiliation(s)
- Henry N Taunt
- a Algenuity, Eden Laboratory , Stewartby , United Kingdom
| | - Laura Stoffels
- b Algal Research Group, Institute of Structural and Molecular Biology , University College London , Gower Street , London , United Kingdom
| | - Saul Purton
- b Algal Research Group, Institute of Structural and Molecular Biology , University College London , Gower Street , London , United Kingdom
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18
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Nielsen AZ, Mellor SB, Vavitsas K, Wlodarczyk AJ, Gnanasekaran T, Perestrello Ramos H de Jesus M, King BC, Bakowski K, Jensen PE. Extending the biosynthetic repertoires of cyanobacteria and chloroplasts. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 87:87-102. [PMID: 27005523 DOI: 10.1111/tpj.13173] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 03/16/2016] [Accepted: 03/18/2016] [Indexed: 05/20/2023]
Abstract
Chloroplasts in plants and algae and photosynthetic microorganisms such as cyanobacteria are emerging hosts for sustainable production of valuable biochemicals, using only inorganic nutrients, water, CO2 and light as inputs. In the past decade, many bioengineering efforts have focused on metabolic engineering and synthetic biology in the chloroplast or in cyanobacteria for the production of fuels, chemicals and complex, high-value bioactive molecules. Biosynthesis of all these compounds can be performed in photosynthetic organelles/organisms by heterologous expression of the appropriate pathways, but this requires optimization of carbon flux and reducing power, and a thorough understanding of regulatory pathways. Secretion or storage of the compounds produced can be exploited for the isolation or confinement of the desired compounds. In this review, we explore the use of chloroplasts and cyanobacteria as biosynthetic compartments and hosts, and we estimate the levels of production to be expected from photosynthetic hosts in light of the fraction of electrons and carbon that can potentially be diverted from photosynthesis. The supply of reducing power, in the form of electrons derived from the photosynthetic light reactions, appears to be non-limiting, but redirection of the fixed carbon via precursor molecules presents a challenge. We also discuss the available synthetic biology tools and the need to expand the molecular toolbox to facilitate cellular reprogramming for increased production yields in both cyanobacteria and chloroplasts.
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Affiliation(s)
- Agnieszka Zygadlo Nielsen
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Silas Busck Mellor
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Konstantinos Vavitsas
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Artur Jacek Wlodarczyk
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Thiyagarajan Gnanasekaran
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Maria Perestrello Ramos H de Jesus
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Brian Christopher King
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Kamil Bakowski
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Poul Erik Jensen
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
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19
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Wannathong T, Waterhouse JC, Young REB, Economou CK, Purton S. New tools for chloroplast genetic engineering allow the synthesis of human growth hormone in the green alga Chlamydomonas reinhardtii. Appl Microbiol Biotechnol 2016; 100:5467-77. [PMID: 26887319 PMCID: PMC4875957 DOI: 10.1007/s00253-016-7354-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 01/18/2016] [Accepted: 01/23/2016] [Indexed: 01/09/2023]
Abstract
In recent years, there has been an increasing interest in the exploitation of microalgae in industrial biotechnology. Potentially, these phototrophic eukaryotes could be used for the low-cost synthesis of valuable recombinant products such as bioactive metabolites and therapeutic proteins. The algal chloroplast in particular represents an attractive target for such genetic engineering, both because it houses major metabolic pathways and because foreign genes can be targeted to specific loci within the chloroplast genome, resulting in high-level, stable expression. However, routine methods for chloroplast genetic engineering are currently available only for one species-Chlamydomonas reinhardtii-and even here, there are limitations to the existing technology, including the need for an expensive biolistic device for DNA delivery, the lack of robust expression vectors, and the undesirable use of antibiotic resistance markers. Here, we describe a new strain and vectors for targeted insertion of transgenes into a neutral chloroplast locus that (i) allow scar-less fusion of a transgenic coding sequence to the promoter/5'UTR element of the highly expressed endogenous genes psaA or atpA, (ii) employ the endogenous gene psbH as an effective but benign selectable marker, and (iii) ensure the successful integration of the transgene construct in all transformant lines. Transformation is achieved by a simple and cheap method of agitation of a DNA/cell suspension with glass beads, with selection based on the phototrophic rescue of a cell wall-deficient ΔpsbH strain. We demonstrate the utility of these tools in the creation of a transgenic line that produces high levels of functional human growth hormone.
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Affiliation(s)
- Thanyanan Wannathong
- Department of Biology, Faculty of Science, Silpakorn University, Nakornpathom, 73000, Thailand
| | - Janet C Waterhouse
- Algal Research Group, Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Rosanna E B Young
- Algal Research Group, Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Chloe K Economou
- Algal Research Group, Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Saul Purton
- Algal Research Group, Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK.
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20
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Doron L, Segal N, Shapira M. Transgene Expression in Microalgae-From Tools to Applications. FRONTIERS IN PLANT SCIENCE 2016; 7:505. [PMID: 27148328 PMCID: PMC4840263 DOI: 10.3389/fpls.2016.00505] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 03/29/2016] [Indexed: 05/17/2023]
Abstract
Microalgae comprise a biodiverse group of photosynthetic organisms that reside in water sources and sediments. The green microalgae Chlamydomonas reinhardtii was adopted as a useful model organism for studying various physiological systems. Its ability to grow under both photosynthetic and heterotrophic conditions allows efficient growth of non-photosynthetic mutants, making Chlamydomonas a useful genetic tool to study photosynthesis. In addition, this green alga can grow as haploid or diploid cells, similar to yeast, providing a powerful genetic system. As a result, easy and efficient transformation systems have been developed for Chlamydomonas, targeting both the chloroplast and nuclear genomes. Since microalgae comprise a rich repertoire of species that offer variable advantages for biotech and biomed industries, gene transfer technologies were further developed for many microalgae to allow for the expression of foreign proteins of interest. Expressing foreign genes in the chloroplast enables the targeting of foreign DNA to specific sites by homologous recombination. Chloroplast transformation also allows for the introduction of genes encoding several enzymes from a complex pathway, possibly as an operon. Expressing foreign proteins in the chloroplast can also be achieved by introducing the target gene into the nuclear genome, with the protein product bearing a targeting signal that directs import of the transgene-product into the chloroplast, like other endogenous chloroplast proteins. Integration of foreign genes into the nuclear genome is mostly random, resulting in large variability between different clones, such that extensive screening is required. The use of different selection modalities is also described, with special emphasis on the use of herbicides and metabolic markers which are considered to be friendly to the environment, as compared to drug-resistance genes that are commonly used. Finally, despite the development of a wide range of transformation tools and approaches, expression of foreign genes in microalgae suffers from low efficiency. Thus, novel tools have appeared in recent years to deal with this problem. Finally, while C. reinhardtii was traditionally used as a model organism for the development of transformation systems and their subsequent improvement, similar technologies can be adapted for other microalgae that may have higher biotechnological value.
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21
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Gangl D, Zedler JAZ, Rajakumar PD, Martinez EMR, Riseley A, Włodarczyk A, Purton S, Sakuragi Y, Howe CJ, Jensen PE, Robinson C. Biotechnological exploitation of microalgae. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:6975-90. [PMID: 26400987 DOI: 10.1093/jxb/erv426] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Microalgae are a diverse group of single-cell photosynthetic organisms that include cyanobacteria and a wide range of eukaryotic algae. A number of microalgae contain high-value compounds such as oils, colorants, and polysaccharides, which are used by the food additive, oil, and cosmetic industries, among others. They offer the potential for rapid growth under photoautotrophic conditions, and they can grow in a wide range of habitats. More recently, the development of genetic tools means that a number of species can be transformed and hence used as cell factories for the production of high-value chemicals or recombinant proteins. In this article, we review exploitation use of microalgae with a special emphasis on genetic engineering approaches to develop cell factories, and the use of synthetic ecology approaches to maximize productivity. We discuss the success stories in these areas, the hurdles that need to be overcome, and the potential for expanding the industry in general.
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Affiliation(s)
- Doris Gangl
- Centre for Molecular Processing, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Julie A Z Zedler
- Centre for Molecular Processing, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Priscilla D Rajakumar
- Institute of Structural & Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Erick M Ramos Martinez
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark
| | - Anthony Riseley
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Artur Włodarczyk
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark
| | - Saul Purton
- Institute of Structural & Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Yumiko Sakuragi
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark
| | - Christopher J Howe
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Poul Erik Jensen
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark
| | - Colin Robinson
- Centre for Molecular Processing, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
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22
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Zhan Y, Dhaliwal JS, Adjibade P, Uniacke J, Mazroui R, Zerges W. Localized control of oxidized RNA. J Cell Sci 2015; 128:4210-9. [PMID: 26449969 DOI: 10.1242/jcs.175232] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 09/23/2015] [Indexed: 12/23/2022] Open
Abstract
The oxidation of biological molecules by reactive oxygen species (ROS) can render them inactive or toxic. This includes the oxidation of RNA, which appears to underlie the detrimental effects of oxidative stress, aging and certain neurodegenerative diseases. Here, we investigate the management of oxidized RNA in the chloroplast of the green alga Chlamydomonas reinhardtii. Our immunofluorescence microscopy results reveal that oxidized RNA (with 8-hydroxyguanine) is localized in the pyrenoid, a chloroplast microcompartment where CO2 is assimilated by the Calvin cycle enzyme Rubisco. Results of genetic analyses support a requirement for the Rubisco large subunit (RBCL), but not Rubisco, in the management of oxidized RNA. An RBCL pool that can carry out such a 'moonlighting' function is revealed by results of biochemical fractionation experiments. We also show that human (HeLa) cells localize oxidized RNA to cytoplasmic foci that are distinct from stress granules, processing bodies and mitochondria. Our results suggest that the compartmentalization of oxidized RNA management is a general phenomenon and therefore has some fundamental significance.
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Affiliation(s)
- Yu Zhan
- Biology Department & Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke W, Montreal, Quebec, Canada H4B 1R6
| | - James S Dhaliwal
- Biology Department & Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke W, Montreal, Quebec, Canada H4B 1R6
| | - Pauline Adjibade
- Department of Molecular Biology, Medical Biochemistry, and Pathology, Laval University, Centre de Recherche le CHU de Quebec, Quebec, Canada G1V 4G2
| | - James Uniacke
- Biology Department & Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke W, Montreal, Quebec, Canada H4B 1R6
| | - Rachid Mazroui
- Department of Molecular Biology, Medical Biochemistry, and Pathology, Laval University, Centre de Recherche le CHU de Quebec, Quebec, Canada G1V 4G2
| | - William Zerges
- Biology Department & Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke W, Montreal, Quebec, Canada H4B 1R6
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23
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Varela JC, Pereira H, Vila M, León R. Production of carotenoids by microalgae: achievements and challenges. PHOTOSYNTHESIS RESEARCH 2015; 125:423-36. [PMID: 25921207 DOI: 10.1007/s11120-015-0149-2] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 04/21/2015] [Indexed: 05/26/2023]
Abstract
Carotenoids are a wide group of lipophylic isoprenoids synthesized by all photosynthetic organisms and also by some non-photosynthetic bacteria and fungi. Animals, which cannot synthesize carotenoids de novo, must include them in their diet to fulfil essential provitamin, antioxidant, or colouring requirements. Carotenoids are indispensable in light harvesting and energy transfer during photosynthesis and in the protection of the photosynthetic apparatus against photooxidative damage. In this review, we outline the factors inducing carotenoid accumulation in microalgae, the knowledge acquired on the metabolic pathways responsible for their biosynthesis, and the recent achievements in the genetic engineering of this pathway. Despite the considerable progress achieved in understanding and engineering algal carotenogenesis, many aspects remain to be elucidated. The increasing number of sequenced microalgal genomes and the data generated by high-throughput technologies will enable a better understanding of carotenoid biosynthesis in microalgae. Moreover, the growing number of industrial microalgal species genetically modified will allow the production of novel strains with enhanced carotenoid contents.
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Affiliation(s)
- João C Varela
- Centre of Marine Science, University of Algarve, Campus de Gambelas, Faro, Portugal
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24
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Braun-Galleani S, Baganz F, Purton S. Improving recombinant protein production in the Chlamydomonas reinhardtii chloroplast using vivid Verde Fluorescent Protein as a reporter. Biotechnol J 2015; 10:1289-97. [PMID: 26098300 PMCID: PMC4985702 DOI: 10.1002/biot.201400566] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Revised: 05/15/2015] [Accepted: 06/18/2015] [Indexed: 11/10/2022]
Abstract
Microalgae have potential as platforms for the synthesis of high-value recombinant proteins due to their many beneficial attributes including ease of cultivation, lack of pathogenic agents, and low-cost downstream processing. However, current recombinant protein levels are low compared to other microbial platforms and stable insertion of transgenes is available in only a few microalgal species. We have explored different strategies aimed at increasing growth rate and recombinant protein production in the Chlamydomonas reinhardtii chloroplast. A novel fluorescent protein (vivid Verde Fluorescent Protein, VFP) was expressed under the control of the native atpA promoter/5'UTR element. VFP levels were detected by western blotting, with increased protein levels observed when co-expressed with a gene encoding the Escherichia coli Spy chaperone. We used these transformant lines to study the effect of temperature, light and media on recombinant protein production and cell growth. VFP levels and fluorescence, assessed by flow cytometry, allowed a determination of improved cultivation conditions as 30°C under mixotrophic mode. These conditions were tested for the accumulation of an antimicrobial endolysin (Cpl-1) of potential commercial interest, observing that the outcome obtained for VFP could not be easily replicated for Cpl-1. This study suggests that recombinant protein expression is product-specific and needs to be optimized individually.
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Affiliation(s)
| | - Frank Baganz
- Department of Biochemical Engineering, University College London, United Kingdom
| | - Saul Purton
- Institute of Structural and Molecular Biology, University College London, United Kingdom
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25
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Yang W, Catalanotti C, Wittkopp TM, Posewitz MC, Grossman AR. Algae after dark: mechanisms to cope with anoxic/hypoxic conditions. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 82:481-503. [PMID: 25752440 DOI: 10.1111/tpj.12823] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 02/28/2015] [Accepted: 03/03/2015] [Indexed: 06/04/2023]
Abstract
Chlamydomonas reinhardtii is a unicellular, soil-dwelling (and aquatic) green alga that has significant metabolic flexibility for balancing redox equivalents and generating ATP when it experiences hypoxic/anoxic conditions. The diversity of pathways available to ferment sugars is often revealed in mutants in which the activities of specific branches of fermentative metabolism have been eliminated; compensatory pathways that have little activity in parental strains under standard laboratory fermentative conditions are often activated. The ways in which these pathways are regulated and integrated have not been extensively explored. In this review, we primarily discuss the intricacies of dark anoxic metabolism in Chlamydomonas, but also discuss aspects of dark oxic metabolism, the utilization of acetate, and the relatively uncharacterized but critical interactions that link chloroplastic and mitochondrial metabolic networks.
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Affiliation(s)
- Wenqiang Yang
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| | - Claudia Catalanotti
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| | - Tyler M Wittkopp
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
| | - Matthew C Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO, 80401, USA
| | - Arthur R Grossman
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
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26
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Buck A, Moore LR, Lane CD, Kumar A, Stroff C, White N, Xue W, Chalmers JJ, Zborowski M. Magnetic separation of algae genetically modified for increased intracellular iron uptake. JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS 2015; 380:201-204. [PMID: 29353957 PMCID: PMC5774641 DOI: 10.1016/j.jmmm.2014.09.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Algae were investigated in the past as a potential source of biofuel and other useful chemical derivatives. Magnetic separation of algae by iron oxide nanoparticle binding to cells has been proposed by others for dewatering of cellular mass prior to lipid extraction. We have investigated feasibility of magnetic separation based on the presence of natural iron stores in the cell, such as the ferritin in Auxenochlorella protothecoides (A. p.) strains. The A. p. cell constructs were tested for inserted genes and for increased intracellular iron concentration by inductively coupled plasma atomic absorption (ICP-AA). They were grown in Sueoka's modified high salt media with added vitamin B1 and increasing concentration of soluble iron compound (FeCl3 EDTA, from 1× to 8× compared to baseline). The cell magnetic separation conditions were tested using a thin rectangular flow channel pressed against interpolar gaps of a permanent magnet forming a separation system of a well-defined fluid flow and magnetic fringing field geometry (up to 2.2 T and 1,000 T/m) dubbed "magnetic deposition microscopy", or MDM. The presence of magnetic cells in suspension was detected by formation of characteristic deposition bands at the edges of the magnet interpolar gaps, amenable to optical scanning and microscopic examination. The results demonstrated increasing cellular Fe uptake with increasing Fe concentration in the culture media in wild type strain and in selected genetically-modified constructs, leading to magnetic separation without magnetic particle binding. The throughput in this study is not sufficient for an economical scale harvest.
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Affiliation(s)
- Amy Buck
- Case Western Reserve University, Cleveland, Ohio, U.S.A
- Cleveland Clinic, Cleveland, Ohio, U.S.A
| | | | | | | | | | | | - Wei Xue
- The Ohio State University, Columbus, OH
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Young REB, Purton S. Cytosine deaminase as a negative selectable marker for the microalgal chloroplast: a strategy for the isolation of nuclear mutations that affect chloroplast gene expression. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 80:915-25. [PMID: 25234691 PMCID: PMC4282525 DOI: 10.1111/tpj.12675] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 09/04/2014] [Accepted: 09/16/2014] [Indexed: 05/09/2023]
Abstract
Negative selectable markers are useful tools for forward-genetic screens aimed at identifying trans-acting factors that are required for expression of specific genes. Transgenic lines harbouring the marker fused to a gene element, such as a promoter, may be mutagenized to isolate loss-of-function mutants able to survive under selection. Such a strategy allows the molecular dissection of factors that are essential for expression of the gene. Expression of individual chloroplast genes in plants and algae typically requires one or more nuclear-encoded factors that act at the post-transcriptional level, often through interaction with the 5' UTR of the mRNA. To study such nuclear control further, we have developed the Escherichia coli cytosine deaminase gene codA as a conditional negative selectable marker for use in the model green alga Chlamydomonas reinhardtii. We show that a codon-optimized variant of codA with three amino acid substitutions confers sensitivity to 5-fluorocytosine (5-FC) when expressed in the chloroplast under the control of endogenous promoter/5' UTR elements from the photosynthetic genes psaA or petA. UV mutagenesis of the psaA transgenic line allowed recovery of 5-FC-resistant, photosynthetically deficient lines harbouring mutations in the nuclear gene for the factor TAA1 that is required for psaA translation. Similarly, the petA line was used to isolate mutants of the petA mRNA stability factor MCA1 and the translation factor TCA1. The codA marker may be used to identify critical residues in known nuclear factors and to aid the discovery of additional factors required for expression of chloroplast genes.
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Affiliation(s)
- Rosanna E B Young
- Algal Research Group, Institute of Structural and Molecular Biology, University College LondonGower Street, London, WC1E 6BT, UK
| | - Saul Purton
- Algal Research Group, Institute of Structural and Molecular Biology, University College LondonGower Street, London, WC1E 6BT, UK
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28
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Economou C, Wannathong T, Szaub J, Purton S. A simple, low-cost method for chloroplast transformation of the green alga Chlamydomonas reinhardtii. Methods Mol Biol 2014; 1132:401-11. [PMID: 24599870 DOI: 10.1007/978-1-62703-995-6_27] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The availability of routine techniques for the genetic manipulation of the chloroplast genome of Chlamydomonas reinhardtii has allowed a plethora of reverse-genetic studies of chloroplast biology using this alga as a model organism. These studies range from fundamental investigations of chloroplast gene function and regulation to sophisticated metabolic engineering programs and to the development of the algal chloroplast as a platform for producing high-value recombinant proteins. The established method for delivering transforming DNA into the Chlamydomonas chloroplast involves microparticle bombardment, with the selection of transformant lines most commonly involving the use of antibiotic resistance markers. In this chapter we describe a simpler and cheaper delivery method in which cell/DNA suspensions are agitated with glass beads: a method that is more commonly used for nuclear transformation of Chlamydomonas. Furthermore, we highlight the use of an expression vector (pASapI) that employs an endogenous gene as a selectable marker, thereby avoiding the contentious issue of antibiotic resistance determinants in transgenic lines.
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Affiliation(s)
- Chloe Economou
- Institute for Structural and Molecular Biology, University College London, London, UK
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Chen HC, Melis A. Marker-free genetic engineering of the chloroplast in the green microalga Chlamydomonas reinhardtii. PLANT BIOTECHNOLOGY JOURNAL 2013; 11:818-28. [PMID: 23647698 DOI: 10.1111/pbi.12073] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 03/05/2013] [Accepted: 03/20/2013] [Indexed: 05/11/2023]
Abstract
The work applied a transgene expression method based on the replacement of an inactive rbcL gene as the selection marker in Chlamydomonas reinhardtii chloroplasts. The native rbcL gene in strain CC2653 has a point mutation that causes early translation termination, thus resulting in a photosynthesis mutant. Recovery of rbcL function for selection is offered along with the heterologous expression of the alcohol dehydrogenase ADH1 gene from Saccharomyces cerevisiae in the Chlamydomonas chloroplast. The CrCpADH1 gene was inserted via double homologous recombination in the psaB-rbcL chloroplast intergenic region of recipient strain CC2653, using the psaB and rbcL gene sequences for the double homologous recombination. This transformation conferred a functional rbcL gene and expression of the CrCpADH1 transgene in the recipient strain. This method alleviated the need to use antibiotics for selection, resulting in a negligible number of false positives during screening, and attaining a transformation efficiency greater than 90%. The approach also ensured segregation of chloroplast DNA copies, so as to achieve homoplasmy of the transformant chloroplast DNA, with a concomitant elimination of recipient strain Cp DNA. High levels of steady-state CrCpADH1 transcripts were detected in the homoplasmic transformants. However, CrCpADH1 protein levels were attenuated under continuous illumination growth conditions due to oxygen accumulation in the cells. Under conditions of low oxygen partial pressure, or anoxia, accumulation of CrCpADH1 protein in the cells and ethanol in the growth medium was observed. A metabolic pathway for ethanol production is proposed in Chlamydomonas, mediated by the chloroplast-localized CrCpADH1 transgenic enzyme.
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Affiliation(s)
- Hsu-Ching Chen
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
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Banti V, Giuntoli B, Gonzali S, Loreti E, Magneschi L, Novi G, Paparelli E, Parlanti S, Pucciariello C, Santaniello A, Perata P. Low oxygen response mechanisms in green organisms. Int J Mol Sci 2013; 14:4734-61. [PMID: 23446868 PMCID: PMC3634410 DOI: 10.3390/ijms14034734] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 02/20/2013] [Accepted: 02/21/2013] [Indexed: 01/04/2023] Open
Abstract
Low oxygen stress often occurs during the life of green organisms, mostly due to the environmental conditions affecting oxygen availability. Both plants and algae respond to low oxygen by resetting their metabolism. The shift from mitochondrial respiration to fermentation is the hallmark of anaerobic metabolism in most organisms. This involves a modified carbohydrate metabolism coupled with glycolysis and fermentation. For a coordinated response to low oxygen, plants exploit various molecular mechanisms to sense when oxygen is either absent or in limited amounts. In Arabidopsis thaliana, a direct oxygen sensing system has recently been discovered, where a conserved N-terminal motif on some ethylene responsive factors (ERFs), targets the fate of the protein under normoxia/hypoxia. In Oryza sativa, this same group of ERFs drives physiological and anatomical modifications that vary in relation to the genotype studied. The microalga Chlamydomonas reinhardtii responses to low oxygen seem to have evolved independently of higher plants, posing questions on how the fermentative metabolism is modulated. In this review, we summarize the most recent findings related to these topics, highlighting promising developments for the future.
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Affiliation(s)
- Valeria Banti
- PlantLab, Institute of Life Sciences, Scuola Superiore Sant’Anna, Via Mariscoglio 34, Pisa 56124, Italy; E-Mails: (V.B.); (B.G.); (S.G.); (G.N.); (E.P.); (S.P.); (C.P.); (A.S.)
| | - Beatrice Giuntoli
- PlantLab, Institute of Life Sciences, Scuola Superiore Sant’Anna, Via Mariscoglio 34, Pisa 56124, Italy; E-Mails: (V.B.); (B.G.); (S.G.); (G.N.); (E.P.); (S.P.); (C.P.); (A.S.)
| | - Silvia Gonzali
- PlantLab, Institute of Life Sciences, Scuola Superiore Sant’Anna, Via Mariscoglio 34, Pisa 56124, Italy; E-Mails: (V.B.); (B.G.); (S.G.); (G.N.); (E.P.); (S.P.); (C.P.); (A.S.)
| | - Elena Loreti
- Institute of Agricultural Biology and Biotechnology, National Research Council, Via Moruzzi 1, Pisa 56100, Italy; E-Mail:
| | - Leonardo Magneschi
- Institute of Plant Biochemistry and Biotechnology, University of Münster, Schlossplatz 8, Münster 48143, Germany; E-Mail:
| | - Giacomo Novi
- PlantLab, Institute of Life Sciences, Scuola Superiore Sant’Anna, Via Mariscoglio 34, Pisa 56124, Italy; E-Mails: (V.B.); (B.G.); (S.G.); (G.N.); (E.P.); (S.P.); (C.P.); (A.S.)
| | - Eleonora Paparelli
- PlantLab, Institute of Life Sciences, Scuola Superiore Sant’Anna, Via Mariscoglio 34, Pisa 56124, Italy; E-Mails: (V.B.); (B.G.); (S.G.); (G.N.); (E.P.); (S.P.); (C.P.); (A.S.)
| | - Sandro Parlanti
- PlantLab, Institute of Life Sciences, Scuola Superiore Sant’Anna, Via Mariscoglio 34, Pisa 56124, Italy; E-Mails: (V.B.); (B.G.); (S.G.); (G.N.); (E.P.); (S.P.); (C.P.); (A.S.)
| | - Chiara Pucciariello
- PlantLab, Institute of Life Sciences, Scuola Superiore Sant’Anna, Via Mariscoglio 34, Pisa 56124, Italy; E-Mails: (V.B.); (B.G.); (S.G.); (G.N.); (E.P.); (S.P.); (C.P.); (A.S.)
| | - Antonietta Santaniello
- PlantLab, Institute of Life Sciences, Scuola Superiore Sant’Anna, Via Mariscoglio 34, Pisa 56124, Italy; E-Mails: (V.B.); (B.G.); (S.G.); (G.N.); (E.P.); (S.P.); (C.P.); (A.S.)
| | - Pierdomenico Perata
- PlantLab, Institute of Life Sciences, Scuola Superiore Sant’Anna, Via Mariscoglio 34, Pisa 56124, Italy; E-Mails: (V.B.); (B.G.); (S.G.); (G.N.); (E.P.); (S.P.); (C.P.); (A.S.)
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Pourmir A, Johannes TW. Directed evolution: selection of the host organism. Comput Struct Biotechnol J 2012; 2:e201209012. [PMID: 24688653 PMCID: PMC3962113 DOI: 10.5936/csbj.201209012] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 10/06/2012] [Accepted: 10/12/2012] [Indexed: 11/29/2022] Open
Abstract
Directed evolution has become a well-established tool for improving proteins and biological systems. A critical aspect of directed evolution is the selection of a suitable host organism for achieving functional expression of the target gene. To date, most directed evolution studies have used either Escherichia coli or Saccharomyces cerevisiae as a host; however, other bacterial and yeast species, as well as mammalian and insect cell lines, have also been successfully used. Recent advances in synthetic biology and genomics have opened the possibility of expanding the use of directed evolution to new host organisms such as microalgae. This review focuses on the different host organisms used in directed evolution and highlights some of the recent directed evolution strategies used in these organisms.
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Affiliation(s)
- Azadeh Pourmir
- Department of Chemical Engineering, The University of Tulsa, 800 S. Tucker Dr, Tulsa, OK 74104, United States
| | - Tyler W Johannes
- Department of Chemical Engineering, The University of Tulsa, 800 S. Tucker Dr, Tulsa, OK 74104, United States
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Gutiérrez CL, Gimpel J, Escobar C, Marshall SH, Henríquez V. CHLOROPLAST GENETIC TOOL FOR THE GREEN MICROALGAE HAEMATOCOCCUS PLUVIALIS (CHLOROPHYCEAE, VOLVOCALES)(1). JOURNAL OF PHYCOLOGY 2012; 48:976-83. [PMID: 27009007 DOI: 10.1111/j.1529-8817.2012.01178.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
At present, there is strong commercial demand for recombinant proteins, such as antigens, antibodies, biopharmaceuticals, and industrial enzymes, which cannot be fulfilled by existing procedures. Thus, an intensive search for alternative models that may provide efficiency, safety, and quality control is being undertaken by a number of laboratories around the world. The chloroplast of the eukaryotic microalgae Haematococcus pluvialis Flotow has arisen as a candidate for a novel expression platform for recombinant protein production. However, there are important drawbacks that need to be resolved before it can become such a system. The most significant of these are chloroplast genome characterizations, and the development of chloroplast transformation vectors based upon specific endogenous promoters and on homologous targeting regions. In this study, we report the identification and characterization of endogenous chloroplast sequences for use as genetic tools for the construction of H. pluvialis specific expression vectors to efficiently transform the chloroplast of this microalga via microprojectile bombardment. As a consequence, H. pluvialis shows promise as a platform for expressing recombinant proteins for biotechnological applications, for instance, the development of oral vaccines for aquaculture.
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Affiliation(s)
- Carla L Gutiérrez
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma. Valparaíso, Chile CREAS, Centro Regional de Alimentos Saludables, Valparaíso, Chile NBC, Núcleo de Biotecnología Curauma, Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma. Valparaíso, Chile CREAS, Centro Regional de Alimentos Saludables, Valparaíso, Chile NBC, Núcleo de Biotecnología Curauma, Curauma, Valparaíso, Chile
| | - Javier Gimpel
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma. Valparaíso, Chile CREAS, Centro Regional de Alimentos Saludables, Valparaíso, Chile NBC, Núcleo de Biotecnología Curauma, Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma. Valparaíso, Chile CREAS, Centro Regional de Alimentos Saludables, Valparaíso, Chile NBC, Núcleo de Biotecnología Curauma, Curauma, Valparaíso, Chile
| | - Carolina Escobar
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma. Valparaíso, Chile CREAS, Centro Regional de Alimentos Saludables, Valparaíso, Chile NBC, Núcleo de Biotecnología Curauma, Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma. Valparaíso, Chile CREAS, Centro Regional de Alimentos Saludables, Valparaíso, Chile NBC, Núcleo de Biotecnología Curauma, Curauma, Valparaíso, Chile
| | - Sergio H Marshall
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma. Valparaíso, Chile CREAS, Centro Regional de Alimentos Saludables, Valparaíso, Chile NBC, Núcleo de Biotecnología Curauma, Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma. Valparaíso, Chile CREAS, Centro Regional de Alimentos Saludables, Valparaíso, Chile NBC, Núcleo de Biotecnología Curauma, Curauma, Valparaíso, Chile
| | - Vitalia Henríquez
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma. Valparaíso, Chile CREAS, Centro Regional de Alimentos Saludables, Valparaíso, Chile NBC, Núcleo de Biotecnología Curauma, Curauma, Valparaíso, ChileLaboratorio de Genética e Inmunología Molecular, Instituto de Biología, Facultad de Ciencias. Pontificia Universidad Católica de Valparaíso. Avenida Universidad 330, Campus Curauma. Valparaíso, Chile CREAS, Centro Regional de Alimentos Saludables, Valparaíso, Chile NBC, Núcleo de Biotecnología Curauma, Curauma, Valparaíso, Chile
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Noor-Mohammadi S, Pourmir A, Johannes TW. Method to assemble and integrate biochemical pathways into the chloroplast genome ofChlamydomonas reinhardtii. Biotechnol Bioeng 2012; 109:2896-903. [DOI: 10.1002/bit.24569] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 05/14/2012] [Accepted: 05/21/2012] [Indexed: 11/08/2022]
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Abstract
Volvocine algae are a group of chlorophytes that together comprise a unique model for evolutionary and developmental biology. The species Chlamydomonas reinhardtii and Volvox carteri represent extremes in morphological diversity within the Volvocine clade. Chlamydomonas is unicellular and reflects the ancestral state of the group, while Volvox is multicellular and has evolved numerous innovations including germ-soma differentiation, sexual dimorphism, and complex morphogenetic patterning. The Chlamydomonas genome sequence has shed light on several areas of eukaryotic cell biology, metabolism and evolution, while the Volvox genome sequence has enabled a comparison with Chlamydomonas that reveals some of the underlying changes that enabled its transition to multicellularity, but also underscores the subtlety of this transition. Many of the tools and resources are in place to further develop Volvocine algae as a model for evolutionary genomics.
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Affiliation(s)
- James G Umen
- Donald Danforth Plant Science Center, 975 North Warson Rd., St. Louis, MO 63132 USA
| | - Bradley J S C Olson
- Molecular Cellular and Developmental Biology, Ecological Genomics Institute, Division of Biology, Kansas State University, Manhattan, KS 66506 USA
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Grossman AR, Catalanotti C, Yang W, Dubini A, Magneschi L, Subramanian V, Posewitz MC, Seibert M. Multiple facets of anoxic metabolism and hydrogen production in the unicellular green alga Chlamydomonas reinhardtii. THE NEW PHYTOLOGIST 2011; 190:279-88. [PMID: 21563367 DOI: 10.1111/j.1469-8137.2010.03534.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Many microbes in the soil environment experience micro-oxic or anoxic conditions for much of the late afternoon and night, which inhibit or prevent respiratory metabolism. To sustain the production of energy and maintain vital cellular processes during the night, organisms have developed numerous pathways for fermentative metabolism. This review discusses fermentation pathways identified for the soil-dwelling model alga Chlamydomonas reinhardtii, its ability to produce molecular hydrogen under anoxic conditions through the activity of hydrogenases, and the molecular flexibility associated with fermentative metabolism that has only recently been revealed through the analysis of specific mutant strains.
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Affiliation(s)
- Arthur R Grossman
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA.
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Hannon M, Gimpel J, Tran M, Rasala B, Mayfield S. Biofuels from algae: challenges and potential. BIOFUELS 2010; 1:763-784. [PMID: 21833344 PMCID: PMC3152439 DOI: 10.4155/bfs.10.44] [Citation(s) in RCA: 277] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Algae biofuels may provide a viable alternative to fossil fuels; however, this technology must overcome a number of hurdles before it can compete in the fuel market and be broadly deployed. These challenges include strain identification and improvement, both in terms of oil productivity and crop protection, nutrient and resource allocation and use, and the production of co-products to improve the economics of the entire system. Although there is much excitement about the potential of algae biofuels, much work is still required in the field. In this article, we attempt to elucidate the major challenges to economic algal biofuels at scale, and improve the focus of the scientific community to address these challenges and move algal biofuels from promise to reality.
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Affiliation(s)
- Michael Hannon
- San Diego Center for Algal Biotechnology, University of California San Diego, Division of Biology, La Jolla, CA, USA
| | - Javier Gimpel
- San Diego Center for Algal Biotechnology, University of California San Diego, Division of Biology, La Jolla, CA, USA
| | - Miller Tran
- San Diego Center for Algal Biotechnology, University of California San Diego, Division of Biology, La Jolla, CA, USA
| | - Beth Rasala
- San Diego Center for Algal Biotechnology, University of California San Diego, Division of Biology, La Jolla, CA, USA
| | - Stephen Mayfield
- San Diego Center for Algal Biotechnology, University of California San Diego, Division of Biology, La Jolla, CA, USA
- Author for correspondence: Tel.: +1 858 822 7745;
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Lapidot M, Shrestha RP, Weinstein Y, Arad S. Red Microalgae: From Basic Know-How to Biotechnology. CELLULAR ORIGIN, LIFE IN EXTREME HABITATS AND ASTROBIOLOGY 2010. [DOI: 10.1007/978-90-481-3795-4_11] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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The ARG9 gene encodes the plastid-resident N-acetyl ornithine aminotransferase in the green alga Chlamydomonas reinhardtii. EUKARYOTIC CELL 2009; 8:1460-3. [PMID: 19617392 DOI: 10.1128/ec.00108-09] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Here we report the characterization of the Chlamydomonas reinhardtii gene ARG9, encoding the plastid resident N-acetyl ornithine aminotransferase, which is involved in arginine synthesis. Integration of an engineered ARG9 cassette in the plastid chromosome of the nuclear arg9 mutant restores arginine prototrophy. This suggests that ARG9 could be used as a new selectable marker for plastid transformation.
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Langner U, Jakob T, Stehfest K, Wilhelm C. An energy balance from absorbed photons to new biomass for Chlamydomonas reinhardtii and Chlamydomonas acidophila under neutral and extremely acidic growth conditions. PLANT, CELL & ENVIRONMENT 2009; 32:250-258. [PMID: 19054351 DOI: 10.1111/j.1365-3040.2008.01917.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Chlamydomonas is one of the most well-studied photosynthetic organisms that had important biotechnological potential for future bioproductions of biofuels. However, an energy balance from incident photons to the energy stored in the new biomass is still lacking. In this study, we applied a recently developed system to measure the energy balance for steady state growth of Chlamydomonas reinhardtii grown at pH 6.5, and C. acidophila that was grown at pH 6.5 and 2.6. Energy use efficiency was quantified on the basis of light absorption, photosynthetic quantum yield, photosynthetic and respiratory quotient, and electron partitioning into proteins, carbohydrates and lipids. The results showed that lower growth rates of C. acidophila under both pH conditions were not caused by the differences in the photosynthetic quantum yield or in alternative electron cycling, but rather by differences in the efficiency of light absorption and increased dark respiration. Analysis of the macromolecular composition of the cells during the light phase showed that C. acidophila uses biosynthetic electrons preferentially for carbohydrate synthesis but not for synthesis of lipids. This led to a strong diurnal cycle of the C/N ratio and could explain the higher dark respiration of C. acidophila compared with C. reinhardtii.
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Affiliation(s)
- Uwe Langner
- University of Leipzig, Institute of Biology I, Department of Plant Physiology, Leipzig, Germany
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