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Abdullah M, Ali Z, Yasin MT, Amanat K, Sarwar F, Khan J, Ahmad K. Advancements in sustainable production of biofuel by microalgae: Recent insights and future directions. ENVIRONMENTAL RESEARCH 2024; 262:119902. [PMID: 39222730 DOI: 10.1016/j.envres.2024.119902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 08/27/2024] [Accepted: 08/30/2024] [Indexed: 09/04/2024]
Abstract
Microalgae is considered as sustainable and viable feedstock for biofuel production due to its significant advantages over terrestrial plants. Algal biofuels have received significant attention among researchers and energy experts owing to an upsurge in global energy issues emanating from depletion in fossil fuel reserves increasing greenhouse gases emission conflict among agricultural crops, traditional biomass feedstock, and potential futuristic energy security. Further, the exploration of value-added microalgae as sustainable and viable feedstock for the production of variety of biofuels such as biogas, bio-hydrogen, bioethanol, and biodiesel are addressed. Moreover, the assessment of life-cycle, energy balance, and environmental impacts of biofuel production from microalgae are briefly discussed. The present study focused on recent advancements in synthetic biology, metabolic engineering tools, algal bio refinery, and the optimization of algae growth conditions. This paper also elucidates the function of microalgae as bio refineries, the conditions of algae-based cultures, and other operational factors that must be adjusted to produce biofuels that are price-competitive with fossil fuels.
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Affiliation(s)
- Muhammad Abdullah
- Industrial Biotechnology Division, National Institute for Biotechnology & Genetic Engineering, P.O. Box 577-Jhang Road, Faisalabad, Pakistan; Institute of Biological Sciences, Khwaja Fareed University of Engineering & Information Technology, 64200, Rahim Yar Khan, Pakistan.
| | - Zain Ali
- Institute of Biological Sciences, Khwaja Fareed University of Engineering & Information Technology, 64200, Rahim Yar Khan, Pakistan.
| | - Muhammad Talha Yasin
- Institute of Biological Sciences, Khwaja Fareed University of Engineering & Information Technology, 64200, Rahim Yar Khan, Pakistan.
| | - Kinza Amanat
- Institute of Biological Sciences, Khwaja Fareed University of Engineering & Information Technology, 64200, Rahim Yar Khan, Pakistan
| | - Fatima Sarwar
- Institute of Chemistry, Khwaja Fareed University of Engineering & Information Technology, 64200, Rahim Yar Khan, Pakistan
| | - Jallat Khan
- Institute of Biological Sciences, Khwaja Fareed University of Engineering & Information Technology, 64200, Rahim Yar Khan, Pakistan; Institute of Chemistry, Khwaja Fareed University of Engineering & Information Technology, 64200, Rahim Yar Khan, Pakistan
| | - Khurshid Ahmad
- State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, No. 1299, Sansha Road, Qingdao, Shandong Province, 266404, PR China
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Song Y, Wang F, Chen L, Zhang W. Engineering Fatty Acid Biosynthesis in Microalgae: Recent Progress and Perspectives. Mar Drugs 2024; 22:216. [PMID: 38786607 PMCID: PMC11122798 DOI: 10.3390/md22050216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 05/06/2024] [Accepted: 05/07/2024] [Indexed: 05/25/2024] Open
Abstract
Microalgal lipids hold significant potential for the production of biodiesel and dietary supplements. To enhance their cost-effectiveness and commercial competitiveness, it is imperative to improve microalgal lipid productivity. Metabolic engineering that targets the key enzymes of the fatty acid synthesis pathway, along with transcription factor engineering, are effective strategies for improving lipid productivity in microalgae. This review provides a summary of the advancements made in the past 5 years in engineering the fatty acid biosynthetic pathway in eukaryotic microalgae. Furthermore, this review offers insights into transcriptional regulatory mechanisms and transcription factor engineering aimed at enhancing lipid production in eukaryotic microalgae. Finally, the review discusses the challenges and future perspectives associated with utilizing microalgae for the efficient production of lipids.
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Affiliation(s)
- Yanhui Song
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China; (Y.S.); (L.C.)
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300350, China
| | - Fangzhong Wang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China; (Y.S.); (L.C.)
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300350, China
- Center for Biosafety Research and Strategy, Tianjin University, Tianjin 300072, China
| | - Lei Chen
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China; (Y.S.); (L.C.)
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300350, China
| | - Weiwen Zhang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China; (Y.S.); (L.C.)
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300350, China
- Center for Biosafety Research and Strategy, Tianjin University, Tianjin 300072, China
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Nakanishi A, Yomogita M, Horimoto T. Evaluation of Cellular Responses by Chlamydomonas reinhardtii in Media Containing Dairy-Processing Residues Derived from Cheese as Nutrients by Analyzing Cell Growth Activity and Comprehensive Gene Transcription Levels. Microorganisms 2024; 12:715. [PMID: 38674659 PMCID: PMC11052199 DOI: 10.3390/microorganisms12040715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 03/28/2024] [Accepted: 03/29/2024] [Indexed: 04/28/2024] Open
Abstract
Utilities of whey powder (WP) and whey protein concentrate 34% powder (WPC34) prepared as dairy-processing residues were evaluated using a green alga Chlamydomonas reinhardtii. Analysis of C. reinhardtii growth showed that the strain used WP and WPC34 as nitrogen sources. Its specific growth rate and maximum cell density in WP-containing medium were higher than those in WPC34-containing medium; growth with WPC34 was improved by adding KCl or K2HPO4, which content was decreased as a result of WPC34's preparation from WP. Although the lipid contents in media containing dairy-processing residues were 2.72 ± 0.31 wt% and 2.62 ± 0.20 wt% with no significant difference, the composition ratio of fatty acid C14 with WPC34 was higher than that with WP and the composition ratio of the sum of fatty acid-C16 and -C18 with WPC34 tended to be lower than that with WP. Additionally, analyses of gene transcription showed that the transcription level of acetyl-CoA carboxylase biotin carboxyl carrier protein in WPC34-containing medium was lower than that in WP-containing medium, possibly affecting the ratios of the chain lengths of fatty acids. The transcription of genes involved in glycolysis and the TCA cycle was outstandingly lower in algae grown in WPC34-containing medium when compared to those cultivated in the presence of WP, resulting in differences in energy production for cell proliferation.
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Affiliation(s)
- Akihito Nakanishi
- School of Bioscience and Biotechnology, Tokyo University of Technology, Tokyo 192-0982, Japan
- Graduate School of Bionics, Tokyo University of Technology, Tokyo 192-0982, Japan;
| | - Misaki Yomogita
- Graduate School of Bionics, Tokyo University of Technology, Tokyo 192-0982, Japan;
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Dai JL, He YJ, Chen HH, Jiang JG. Dual Roles of Two Malic Enzymes in Lipid Biosynthesis and Salt Stress Response in Dunaliella salina. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023. [PMID: 37906521 DOI: 10.1021/acs.jafc.3c04810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Triacylglycerols (TAG) from microalgae can be used as feedstocks for biofuel production to address fuel shortages. Most of the current research has focused on the enzymes involved in TAG biosynthesis. In this study, the effects of malic enzyme (ME), which provides precursor and reducing power for TAG biosynthesis, on biomass and lipid accumulation and its response to salt stress in Dunaliella salina were investigated. The overexpression of DsME1 and DsME2 improved the lipid production, which reached 0.243 and 0.253 g/L and were 30.5 and 36.3% higher than wild type, respectively. The transcript levels of DsME1 and DsME2 increased with increasing salt concentration (0, 1, 2, 3, and 4.5 mol/L NaCl), indicating that DsMEs participated in the salt stress response in D. salina. It was found that cis-acting elements associated with the salt stress response were present on the promoters of two DsMEs. The deletion of the MYB binding site (MBS) on the DsME2 promoter confirmed that MBS drives the expression of DsME2 to participate in osmotic regulation in D. salina. In conclusion, MEs are the critical enzymes that play pivotal roles in lipid accumulation and osmotic regulation.
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Affiliation(s)
- Jv-Liang Dai
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Yu-Jing He
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Hao-Hong Chen
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Jian-Guo Jiang
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
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Li X, Yang M, Sun D, Shi J, Yang M, Feng Y, Xue S. Unique recognition of the microalgal plastidial glycerol-3-phosphate acyltransferase for acyl-ACP. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023; 332:111725. [PMID: 37142097 DOI: 10.1016/j.plantsci.2023.111725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/29/2023] [Accepted: 05/02/2023] [Indexed: 05/06/2023]
Abstract
Plastidial glycerol-3-phosphate acyltransferases (GPATs) catalyze acyl-ACP and glycerol-3-phosphate to synthesize lysophosphatidic acid in vivo, which initiates the formation of various glycerolipids. Although the physiological substrates of plastidial GPATs are acyl-ACPs, acyl-CoAs have been commonly studied on the GPATs in vitro. However, little is known whether there are any distinct features of GPATs towards acyl-ACP and acyl-CoA. In this study, the results showed that the microalgal plastidial GPATs preferred acyl-ACP to acyl-CoA, while surprisingly, the plant-derived plastidial GPATs showed no obvious preferences towards these two acyl carriers. The key residues responsible for the distinct feature of microalgal plastidial GPATs were compared with plant-derived plastidial GPATs in their efficiency to catalyze acyl-ACP and acyl-CoA. Microalgal plastidial GPATs uniquely recognized acyl-ACP as compared to with other acyltransferases. The structure of the acyltransferases-ACP complex highlights only the involvement of the large structural domain in ACP in microalgal plastidial GPAT while in the other acyltransferases, both large and small structural domains were involved in the recognition process. The interaction sites on the plastidial GPAT from the green alga Myrmecia incisa (MiGPAT1) with ACP turned out to be K204, R212 and R266. A unique recognition between the microalgal plastidial GPAT and ACP was elucidated.
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Affiliation(s)
- Xianglong Li
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China
| | - Miao Yang
- Key Laboratory of Plant Biotechnology of Liaoning Province, School of Life Sciences, Liaoning Normal University, Dalian, 116081, China
| | - Dongru Sun
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China
| | - Jianping Shi
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China
| | - Ming Yang
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China
| | - Yanbin Feng
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China.
| | - Song Xue
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China.
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Enhanced accumulation of oil through co-expression of fatty acid and ABC transporters in Chlamydomonas under standard growth conditions. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:54. [PMID: 35596223 PMCID: PMC9123788 DOI: 10.1186/s13068-022-02154-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 05/07/2022] [Indexed: 11/10/2022]
Abstract
Abstract
Background
Chloroplast and endoplasmic reticulum (ER)-localized fatty acid (FA) transporters have been reported to play important roles in oil (mainly triacylglycerols, TAG) biosynthesis. However, whether these FA transporters synergistically contribute to lipid accumulation, and their effect on lipid metabolism in microalgae are unknown.
Results
Here, we co-overexpressed two chloroplast-localized FA exporters (FAX1 and FAX2) and one ER-localized FA transporter (ABCA2) in Chlamydomonas. Under standard growth conditions, FAX1/FAX2/ABCA2 over-expression lines (OE) accumulated up to twofold more TAG than the parental strain UVM4, and the total amounts of major polyunsaturated FAs (PUFA) in TAG increased by 4.7-fold. In parallel, the total FA contents and major membrane lipids in FAX1/FAX2/ABCA2-OE also significantly increased compared with those in the control lines. Additionally, the total accumulation contribution ratio of PUFA, to total FA and TAG synthesis in FAX1/FAX2/ABCA2-OE, was 54% and 40% higher than that in UVM4, respectively. Consistently, the expression levels of genes directly involved in TAG synthesis, such as type-II diacylglycerol acyltransferases (DGTT1, DGTT3 and DGTT5), and phospholipid:diacylglycerol acyltransferase 1 (PDAT1), significantly increased, and the expression of PGD1 (MGDG-specific lipase) was upregulated in FAX1/FAX2/ABCA2-OE compared to UVM4.
Conclusion
These results indicate that the increased expression of FAX1/FAX2/ABCA2 has an additive effect on enhancing TAG, total FA and membrane lipid accumulation and accelerates the PUFA remobilization from membrane lipids to TAG by fine-tuning the key genes involved in lipid metabolism under standard growth conditions. Overall, FAX1/FAX2/ABCA2-OE shows better traits for lipid accumulation than the parental line and previously reported individual FA transporter-OE. Our study provides a potential useful strategy to increase the production of FA-derived energy-rich and value-added compounds in microalgae.
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Yin Y, Raboanatahiry N, Chen K, Chen X, Tian T, Jia J, He H, He J, Guo Z, Yu L, Li M. Class A lysophosphatidic acid acyltransferase 2 from Camelina sativa promotes very long-chain fatty acids accumulation in phospholipid and triacylglycerol. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 112:1141-1158. [PMID: 36209492 DOI: 10.1111/tpj.15999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 09/29/2022] [Accepted: 10/05/2022] [Indexed: 06/16/2023]
Abstract
Very long-chain fatty acids (VLCFAs) are important industrial raw materials and can be produced by genetically modified oil plants. For a long time, class A lysophosphatidic acid acyltransferase (LPAT) was considered unable to promote the accumulation of VLCFA in oil crops. The bottlenecks that the transgenic high VLCFA lines have an oil content penalty and the low amount of VLCFA in phosphatidylcholine remains intractable. In the present study, a class A LPAT2 from Camelina sativa (CsaLPAT2) promoting VLCFAs accumulation in phospholipid was found. Overexpression of CsaLPAT2 alone in Arabidopsis seeds significantly increased the VLCFA content in triacylglycerol, including C20:0, C20:2, C20:3, C22:0, and C22:1. The proportion of phosphatidic acid molecules containing VLCFAs in transgenic seeds reached up to 45%, which was 2.8-fold greater than that in wild type. The proportion of phosphatidylcholine and diacylglycerol molecules containing VLCFAs also increased significantly. Seed size in CsaLPAT2 transgenic lines showed a slight increase without an oil content penalty. The total phospholipid content in the seed of the CsaLPAT2 transgenic line was significantly increased. Furthermore, the function of class A LPAT in promoting the accumulation of VLCFAs is conserved in the representative oil crops of Brassicaceae, such as C. sativa, Arabidopsis thaliana, Brassica napus, Brassica rapa, and Brassica oleracea. The findings of this study provide a promising gene resource for the production of VLCFAs.
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Affiliation(s)
- Yongtai Yin
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Nadia Raboanatahiry
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Kang Chen
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Xinfeng Chen
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Tian Tian
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Jia Jia
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Hongsheng He
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Jianjie He
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zhenyi Guo
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Longjiang Yu
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Maoteng Li
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
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Zhang K, He J, Yin Y, Chen K, Deng X, Yu P, Li H, Zhao W, Yan S, Li M. Lysophosphatidic acid acyltransferase 2 and 5 commonly, but differently, promote seed oil accumulation in Brassica napus. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:83. [PMID: 35962411 PMCID: PMC9375321 DOI: 10.1186/s13068-022-02182-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 08/05/2022] [Indexed: 11/19/2022]
Abstract
Background Increasing seed oil content (SOC) of Brassica napus has become one of the main plant breeding goals over the past decades. Lysophosphatidic acid acyltransferase (LPAT) performs an important molecular function by regulating the production of phosphatidic acid (PA), a key intermediate in the synthesis of membrane and storage lipids. However, the mechanism underlying the effect of LPAT on the SOC of B. napus remains unclear. Results In the present study, significant elevation of SOC was achieved by overexpressing BnLPAT2 and BnLPAT5 in B. napus. RNAi and CRISPR–Cas9 were also successfully used to knock down and knock out these two genes in B. napus where SOC significantly decreased. Meanwhile, we found an accumulation of lipid droplets and oil bodies in seeds of BnLPAT2 and BnLPAT5 overexpression lines, whereas an increase of sugar and protein in Bnlpat2 and Bnlpat5 mutant seeds. Sequential transcriptome analysis was further performed on the developing seeds of the BnLPAT2 and BnLPAT5 overexpression, knockdown, and knockout rapeseed lines. Most differentially expressed genes (DEGs) that were expressed in the middle and late stages of seed development were enriched in photosynthesis and lipid metabolism, respectively. The DEGs involved in fatty acid and lipid biosynthesis were active in the overexpression lines but were relatively inactive in the knockdown and knockout lines. Further analysis revealed that the biological pathways related to fatty acid/lipid anabolism and carbohydrate metabolism were specifically enriched in the BnLPAT2 overexpression lines. Conclusions BnLPAT2 and BnLPAT5 are essential for seed oil accumulation. BnLPAT2 preferentially promoted diacylglycerol synthesis to increase SOC, whereas BnLPAT5 tended to boost PA synthesis for membrane lipid generation. Taken together, BnLPAT2 and BnLPAT5 can jointly but differently promote seed oil accumulation in B. napus. This study provides new insights into the potential mechanisms governing the promotion of SOC by BnLPAT2 and BnLPAT5 in the seeds of B. napus. Supplementary Information The online version contains supplementary material available at 10.1186/s13068-022-02182-2.
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Chen G, Harwood JL, Lemieux MJ, Stone SJ, Weselake RJ. Acyl-CoA:diacylglycerol acyltransferase: Properties, physiological roles, metabolic engineering and intentional control. Prog Lipid Res 2022; 88:101181. [PMID: 35820474 DOI: 10.1016/j.plipres.2022.101181] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/31/2022] [Accepted: 07/04/2022] [Indexed: 12/15/2022]
Abstract
Acyl-CoA:diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) catalyzes the last reaction in the acyl-CoA-dependent biosynthesis of triacylglycerol (TAG). DGAT activity resides mainly in membrane-bound DGAT1 and DGAT2 in eukaryotes and bifunctional wax ester synthase-diacylglycerol acyltransferase (WSD) in bacteria, which are all membrane-bound proteins but exhibit no sequence homology to each other. Recent studies also identified other DGAT enzymes such as the soluble DGAT3 and diacylglycerol acetyltransferase (EaDAcT), as well as enzymes with DGAT activities including defective in cuticular ridges (DCR) and steryl and phytyl ester synthases (PESs). This review comprehensively discusses research advances on DGATs in prokaryotes and eukaryotes with a focus on their biochemical properties, physiological roles, and biotechnological and therapeutic applications. The review begins with a discussion of DGAT assay methods, followed by a systematic discussion of TAG biosynthesis and the properties and physiological role of DGATs. Thereafter, the review discusses the three-dimensional structure and insights into mechanism of action of human DGAT1, and the modeled DGAT1 from Brassica napus. The review then examines metabolic engineering strategies involving manipulation of DGAT, followed by a discussion of its therapeutic applications. DGAT in relation to improvement of livestock traits is also discussed along with DGATs in various other eukaryotic organisms.
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Affiliation(s)
- Guanqun Chen
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada.
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, Membrane Protein Disease Research Group, Edmonton T6G 2H7, Canada
| | - Scot J Stone
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
| | - Randall J Weselake
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada
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Choi BY, Shim D, Kong F, Auroy P, Lee Y, Li-Beisson Y, Lee Y, Yamaoka Y. The Chlamydomonas transcription factor MYB1 mediates lipid accumulation under nitrogen depletion. THE NEW PHYTOLOGIST 2022; 235:595-610. [PMID: 35383411 DOI: 10.1111/nph.18141] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/29/2022] [Indexed: 06/14/2023]
Abstract
Microalgae accumulate high levels of oil under stress, but the underlying biosynthetic pathways are not fully understood. We sought to identify key regulators of lipid metabolism under stress conditions. We found that the Chlamydomonas reinhardtii gene encoding the MYB-type transcription factor MYB1 is highly induced under stress conditions. Two myb1 mutants accumulated less total fatty acids and storage lipids than their parental strain upon nitrogen (N) depletion. Transcriptome analysis revealed that genes involved in lipid metabolism are highly enriched in the wild-type but not in the myb1-1 mutant after 4 h of N depletion. Among these genes were several involved in the transport of fatty acids from the chloroplast to the endoplasmic reticulum (ER): acyl-ACP thioesterase (FAT1), Fatty Acid EXporters (FAX1, FAX2), and long-chain acyl-CoA synthetase1 (LACS1). Furthermore, overexpression of FAT1 in the chloroplast increased lipid production. These results suggest that, upon N depletion, MYB1 promotes lipid accumulation by facilitating fatty acid transport from the chloroplast to the ER. This study identifies MYB1 as an important positive regulator of lipid accumulation in C. reinhardtii upon N depletion, adding another player to the established regulators of this process, including NITROGEN RESPONSE REGULATOR 1 (NRR1) and TRIACYLGLYCEROL ACCUMULATION REGULATOR 1 (TAR1).
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Affiliation(s)
- Bae Young Choi
- Department of Life Science, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
| | - Donghwan Shim
- Department of Biological Sciences, Chungnam National University, Daejeon, 34134, Korea
| | - Fantao Kong
- Department of Life Science, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
- School of Bioengineering, Dalian University of Technology, Dalian, 116024, China
| | - Pascaline Auroy
- CEA, CNRS, BIAM, Institut de Biosciences et Biotechnologies Aix-Marseille, Aix Marseille Université, CEA Cadarache, Saint Paul-Lez-Durance, 13108, France
| | - Yuree Lee
- School of Biological Sciences, Seoul National University, Seoul, 08826, Korea
- Research Center for Plant Plasticity, Seoul National University, Seoul, 08826, Korea
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, 08826, Korea
| | - Yonghua Li-Beisson
- CEA, CNRS, BIAM, Institut de Biosciences et Biotechnologies Aix-Marseille, Aix Marseille Université, CEA Cadarache, Saint Paul-Lez-Durance, 13108, France
| | - Youngsook Lee
- Department of Life Science, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
| | - Yasuyo Yamaoka
- Division of Biotechnology, The Catholic University of Korea, Bucheon, 420-743, Korea
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Song JM, Zhang Y, Zhou ZW, Lu S, Ma W, Lu C, Chen LL, Guo L. Oil plant genomes: current state of the science. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2859-2874. [PMID: 35560205 DOI: 10.1093/jxb/erab472] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/22/2021] [Indexed: 05/25/2023]
Abstract
Vegetable oils are an indispensable nutritional component of the human diet as well as important raw materials for a variety of industrial applications such as pharmaceuticals, cosmetics, oleochemicals, and biofuels. Oil plant genomes are highly diverse, and their genetic variation leads to a diversity in oil biosynthesis and accumulation along with agronomic traits. This review discusses plant oil biosynthetic pathways, current state of genome assembly, polyploidy and asymmetric evolution of genomes of oil plants and their wild relatives, and research progress of pan-genomics in oil plants. The availability of complete high-resolution genomes and pan-genomes has enabled the identification of structural variations in the genomes that are associated with the diversity of agronomic and environment fitness traits. These and future genomes also provide powerful tools to understand crop evolution and to harvest the rich natural variations to improve oil crops for enhanced productivity, oil quality, and adaptability to changing environments.
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Affiliation(s)
- Jia-Ming Song
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
- College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Yuting Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Zhi-Wei Zhou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Shaoping Lu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Wei Ma
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Chaofu Lu
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717, USA
| | - Ling-Ling Chen
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
- College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Liang Guo
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
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12
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Latest Expansions in Lipid Enhancement of Microalgae for Biodiesel Production: An Update. ENERGIES 2022. [DOI: 10.3390/en15041550] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Research progress on sustainable and renewable biofuel has gained motion over the years, not just due to the rapid reduction of dwindling fossil fuel supplies but also due to environmental and potential energy security issues as well. Intense interest in microalgae (photosynthetic microbes) as a promising feedstock for third-generation biofuels has grown over recent years. Fuels derived from algae are now considered sustainable biofuels that are promising, renewable, and clean. Therefore, selecting the robust species of microalgae with substantial features for quality biodiesel production is the first step in the way of biofuel production. A contemporary investigation is more focused on several strategies and techniques to achieve higher biomass and triglycerides in microalgae. The improvement in lipid enhancement in microalgae species by genetic manipulation approaches, such as metabolic or genetic alteration, and the use of nanotechnology are the most recent ways of improving the production of biomass and lipids. Hence, the current review collects up-to-date approaches for microalgae lipid increase and biodiesel generation. The strategies for high biomass and high lipid yield are discussed. Additionally, various pretreatment procedures that may aid in lipid harvesting efficiency and improve lipid recovery rate are described.
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13
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Ma H, Zheng J, Li Y, Zhao L, Zou S, Hu Q, Han D. A Novel Bifunctional Wax Ester Synthase Involved in Early Triacylglycerol Accumulation in Unicellular Green Microalga Haematococcus pluvialis Under High Light Stress. Front Bioeng Biotechnol 2022; 9:794714. [PMID: 35111735 PMCID: PMC8802113 DOI: 10.3389/fbioe.2021.794714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 11/30/2021] [Indexed: 11/20/2022] Open
Abstract
The bulk of neutral lipids, including astaxanthin esters and triacylglycerols (TAGs), are accumulated in the green microalga Haematococcus pluvialis under high light (HL) stress. In this study, a novel bifunctional wax ester synthase (WS) gene was cloned from H. pluvialis upon HL stress. The overexpression of HpWS restored the biosynthesis of wax esters and TAGs in neutral lipid-deficient yeast mutant Saccharomyces cerevisiae H1246 fed with C18 alcohol and C18:1/C18:3 fatty acids, respectively. Under HL stress, HpWS was substantially upregulated at the transcript level, prior to that of the type I diacylglycerol:acyl-CoA acyltransferase encoding gene (HpDGAT1). HpDGAT1 is the major TAG synthase in H. pluvialis. In addition, the application of xanthohumol (a DGAT1/2 inhibitor) in the H. pluvialis cells did not completely eliminate the TAG biosynthesis under HL stress at 24 h. These results indicated that HpWS may contribute to the accumulation of TAGs in H. pluvialis at the early stage under HL stress. In addition, the overexpression of HpWS in Chlamydomonas reinhardtii bkt5, which is engineered to produce free astaxanthin, enhanced the production of TAGs and astaxanthin. Our findings broaden the understanding of TAG biosynthesis in microalgae and provide a new molecular target for genetic manipulation in biotechnological applications.
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Affiliation(s)
- Haiyan Ma
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- *Correspondence: Haiyan Ma,
| | - Jie Zheng
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yanhua Li
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Liang Zhao
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Song Zou
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qiang Hu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Danxiang Han
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
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14
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Oishi Y, Otaki R, Iijima Y, Kumagai E, Aoki M, Tsuzuki M, Fujiwara S, Sato N. Diacylglyceryl-N,N,N-trimethylhomoserine-dependent lipid remodeling in a green alga, Chlorella kessleri. Commun Biol 2022; 5:19. [PMID: 35017659 PMCID: PMC8752610 DOI: 10.1038/s42003-021-02927-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 11/29/2021] [Indexed: 11/08/2022] Open
Abstract
Membrane lipid remodeling contributes to the environmental acclimation of plants. In the green lineage, a betaine lipid, diacylglyceryl-N,N,N-trimethylhomoserine (DGTS), is included exclusively among green algae and nonflowering plants. Here, we show that the green alga Chlorella kessleri synthesizes DGTS under phosphorus-deficient conditions through the eukaryotic pathway via the ER. Simultaneously, phosphatidylcholine and phosphatidylethanolamine, which are similar to DGTS in their zwitterionic properties, are almost completely degraded to release 18.1% cellular phosphorus, and to provide diacylglycerol moieties for a part of DGTS synthesis. This lipid remodeling system that substitutes DGTS for extrachloroplast phospholipids to lower the P-quota operates through the expression induction of the BTA1 gene. Investigation of this lipid remodeling system is necessary in a wide range of lower green plants for a comprehensive understanding of their phosphorus deficiency acclimation strategies.
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Affiliation(s)
- Yutaro Oishi
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Horinouchi 1432-1, Hachioji, Tokyo, 192-0392, Japan
| | - Rie Otaki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Horinouchi 1432-1, Hachioji, Tokyo, 192-0392, Japan
| | - Yukari Iijima
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Horinouchi 1432-1, Hachioji, Tokyo, 192-0392, Japan
| | - Eri Kumagai
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Horinouchi 1432-1, Hachioji, Tokyo, 192-0392, Japan
| | - Motohide Aoki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Horinouchi 1432-1, Hachioji, Tokyo, 192-0392, Japan
| | - Mikio Tsuzuki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Horinouchi 1432-1, Hachioji, Tokyo, 192-0392, Japan
| | - Shoko Fujiwara
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Horinouchi 1432-1, Hachioji, Tokyo, 192-0392, Japan
| | - Norihiro Sato
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Horinouchi 1432-1, Hachioji, Tokyo, 192-0392, Japan.
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15
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Santin A, Russo MT, Ferrante MI, Balzano S, Orefice I, Sardo A. Highly Valuable Polyunsaturated Fatty Acids from Microalgae: Strategies to Improve Their Yields and Their Potential Exploitation in Aquaculture. Molecules 2021; 26:7697. [PMID: 34946780 PMCID: PMC8707597 DOI: 10.3390/molecules26247697] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 11/16/2022] Open
Abstract
Microalgae have a great potential for the production of healthy food and feed supplements. Their ability to convert carbon into high-value compounds and to be cultured in large scale without interfering with crop cultivation makes these photosynthetic microorganisms promising for the sustainable production of lipids. In particular, microalgae represent an alternative source of polyunsaturated fatty acids (PUFAs), whose consumption is related to various health benefits for humans and animals. In recent years, several strategies to improve PUFAs' production in microalgae have been investigated. Such strategies include selecting the best performing species and strains and the optimization of culturing conditions, with special emphasis on the different cultivation systems and the effect of different abiotic factors on PUFAs' accumulation in microalgae. Moreover, developments and results obtained through the most modern genetic and metabolic engineering techniques are described, focusing on the strategies that lead to an increased lipid production or an altered PUFAs' profile. Additionally, we provide an overview of biotechnological applications of PUFAs derived from microalgae as safe and sustainable organisms, such as aquafeed and food ingredients, and of the main techniques (and their related issues) for PUFAs' extraction and purification from microalgal biomass.
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Affiliation(s)
- Anna Santin
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Monia Teresa Russo
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Maria Immacolata Ferrante
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Sergio Balzano
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
- Department of Marine Microbiology and Biogeochemistry, Netherland Institute for Sea Research, Landsdiep 4, 1793 AB Texel, The Netherlands
| | - Ida Orefice
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Angela Sardo
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
- Istituto di Scienze Applicate e Sistemi Intelligenti “Eduardo Caianiello”, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
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16
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Genetic engineering of microalgae for enhanced lipid production. Biotechnol Adv 2021; 52:107836. [PMID: 34534633 DOI: 10.1016/j.biotechadv.2021.107836] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 09/09/2021] [Accepted: 09/09/2021] [Indexed: 12/24/2022]
Abstract
Microalgae have the potential to become microbial cell factories for lipid production. Their ability to convert sunlight and CO2 into valuable lipid compounds has attracted interest from cosmetic, biofuel, food and feed industries. In order to make microalgae-derived products cost-effective and commercially competitive, enhanced growth rates and lipid productivities are needed, which require optimization of cultivation systems and strain improvement. Advances in genetic tool development and omics technologies have increased our understanding of lipid metabolism, which has opened up possibilities for targeted metabolic engineering. In this review we provide a comprehensive overview on the developments made to genetically engineer microalgal strains over the last 30 years. We focus on the strategies that lead to an increased lipid content and altered fatty acid profile. These include the genetic engineering of the fatty acid synthesis pathway, Kennedy pathway, polyunsaturated fatty acid and triacylglycerol metabolisms and fatty acid catabolism. Moreover, genetic engineering of specific transcription factors, NADPH generation and central carbon metabolism, which lead to increase of lipid accumulation are also reviewed.
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17
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Mehariya S, Goswami RK, Karthikeysan OP, Verma P. Microalgae for high-value products: A way towards green nutraceutical and pharmaceutical compounds. CHEMOSPHERE 2021; 280:130553. [PMID: 33940454 DOI: 10.1016/j.chemosphere.2021.130553] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 04/02/2021] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
Microalgae is a renewable bioresource with the potential to replace the conventional fossil-based industrial production of organic chemicals and pharmaceuticals. Moreover, the microalgal biomass contains carotenoids, vitamins, and other biomolecules that are widely used as food supplements. However, the microalgal biomass production, their composition variations, energy-intensive harvesting methods, optimized bio-refinery routes, and lack of techno-economic analysis are the major bottleneck for the life-sized commercialization of this nascent bio-industry. This review discusses the microalgae-derived key bioactive compounds and their applications in different sectors for human health. Furthermore, this review proposes advanced strategies to enhance the productivity of bioactive compounds and highlight the key challenges associated with a safety issue for use of microalgae biomass. It also provides a detailed global scenario and market demand of microalgal bioproducts. In conclusion, this review will provide the concept of microalgal biorefinery to produce bioactive compounds at industrial scale platform for their application in the nutraceutical and pharmaceutical sector considering their current and future market trends.
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Affiliation(s)
- Sanjeet Mehariya
- Department of Engineering, University of Campania "Luigi Vanvitelli", Real Casa Dell'Annunziata, Via Roma 29, 81031, Aversa, CE, Italy; Department of Chemistry, Umeå University, 90187, Umeå, Sweden
| | - Rahul Kumar Goswami
- Bioprocess and Bioenergy Laboratory, Department of Microbiology, Central University of Rajasthan, NH-8, Bandarsindri, Kishangarh, Ajmer, 305817, Rajasthan, India
| | - Obulisamy Parthiba Karthikeysan
- Department of Engineering Technology, College of Technology, University of Houston, Houston, TX, USA; Civil and Environmental Engineering, South Dakota School of Mines and Technology, Rapid City, SD, USA.
| | - Pradeep Verma
- Bioprocess and Bioenergy Laboratory, Department of Microbiology, Central University of Rajasthan, NH-8, Bandarsindri, Kishangarh, Ajmer, 305817, Rajasthan, India.
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18
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Wayne LL, Gachotte DJ, Graupner PR, Adelfinskaya Y, McCaskill DG, Metz JG, Zirkle R, Walsh TA. Plant and algal lysophosphatidic acid acyltransferases increase docosahexaenoic acid accumulation at the sn-2 position of triacylglycerol in transgenic Arabidopsis seed oil. PLoS One 2021; 16:e0256625. [PMID: 34432852 PMCID: PMC8386867 DOI: 10.1371/journal.pone.0256625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/10/2021] [Indexed: 11/21/2022] Open
Abstract
Although docosahexaenoic acid (DHA), an important dietary omega-3 polyunsaturated fatty acid (PUFA), is at present primarily sourced from marine fish, bioengineered crops producing DHA may offer a more sustainable and cost-effective source. DHA has been produced in transgenic oilseed crops, however, DHA in seed oil primarily occupies the sn-1/3 positions of triacylglycerol (TAG) with relatively low amounts of DHA in the sn-2 position. To increase the amount of DHA in the sn-2 position of TAG and in seed oil, putative lysophosphatidic acid acyltransferases (LPAATs) were identified and characterized from the DHA-producing alga Schizochytrium sp. and from soybean (Glycine max). The affinity-purified proteins were confirmed to have LPAAT activity. Expression of the Schizochytrium or soybean LPAATs in DHA-producing Arabidopsis expressing the Schizochytrium PUFA synthase system significantly increased the total amount of DHA in seed oil. A novel sensitive band-selective heteronuclear single quantum coherence (HSQC) NMR method was developed to quantify DHA at the sn-2 position of glycerolipids. More than two-fold increases in sn-2 DHA were observed for Arabidopsis lines expressing Schizochytrium or soybean LPAATs, with one Schizochytrium LPAAT driving DHA accumulation in the sn-2 position to 61% of the total DHA. Furthermore, expression of a soybean LPAAT led to a redistribution of DHA-containing TAG species, with two new TAG species identified. Our results demonstrate that transgenic expression of Schizochytrium or soybean LPAATs can increase the proportion of DHA at the sn-2 position of TAG and the total amount of DHA in the seed oil of a DHA-accumulating oilseed plant. Additionally, the band-selective HSQC NMR method that we developed provides a sensitive and robust method for determining the regiochemistry of DHA in glycerolipids. These findings will benefit the advancement of sustainable sources of DHA via transgenic crops such as canola and soybean.
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Affiliation(s)
- Laura L. Wayne
- Corteva Agriscience, Johnston, Iowa, United States of America
- * E-mail:
| | | | - Paul R. Graupner
- Corteva Agriscience, Indianapolis, Indiana, United States of America
| | | | | | - James G. Metz
- DSM Nutritional Products, Columbia, Maryland, United States of America
| | - Ross Zirkle
- DSM Nutritional Products, Columbia, Maryland, United States of America
| | - Terence A. Walsh
- Corteva Agriscience, Indianapolis, Indiana, United States of America
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19
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Zhang Y, Ye Y, Bai F, Liu J. The oleaginous astaxanthin-producing alga Chromochloris zofingiensis: potential from production to an emerging model for studying lipid metabolism and carotenogenesis. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:119. [PMID: 33992124 PMCID: PMC8126118 DOI: 10.1186/s13068-021-01969-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 05/07/2021] [Indexed: 05/05/2023]
Abstract
The algal lipids-based biodiesel, albeit having advantages over plant oils, still remains high in the production cost. Co-production of value-added products with lipids has the potential to add benefits and is thus believed to be a promising strategy to improve the production economics of algal biodiesel. Chromochloris zofingiensis, a unicellular green alga, has been considered as a promising feedstock for biodiesel production because of its robust growth and ability of accumulating high levels of triacylglycerol under multiple trophic conditions. This alga is also able to synthesize high-value keto-carotenoids and has been cited as a candidate producer of astaxanthin, the strongest antioxidant found in nature. The concurrent accumulation of triacylglycerol and astaxanthin enables C. zofingiensis an ideal cell factory for integrated production of the two compounds and has potential to improve algae-based production economics. Furthermore, with the advent of chromosome-level whole genome sequence and genetic tools, C. zofingiensis becomes an emerging model for studying lipid metabolism and carotenogenesis. In this review, we summarize recent progress on the production of triacylglycerol and astaxanthin by C. zofingiensis. We also update our understanding in the distinctive molecular mechanisms underlying lipid metabolism and carotenogenesis, with an emphasis on triacylglycerol and astaxanthin biosynthesis and crosstalk between the two pathways. Furthermore, strategies for trait improvements are discussed regarding triacylglycerol and astaxanthin synthesis in C. zofingiensis.
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Affiliation(s)
- Yu Zhang
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Ying Ye
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Fan Bai
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Jin Liu
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China.
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20
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Gu X, Cao L, Wu X, Li Y, Hu Q, Han D. A Lipid Bodies-Associated Galactosyl Hydrolase Is Involved in Triacylglycerol Biosynthesis and Galactolipid Turnover in the Unicellular Green Alga Chlamydomonas reinhardtii. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10040675. [PMID: 33807496 PMCID: PMC8065580 DOI: 10.3390/plants10040675] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/28/2021] [Accepted: 03/29/2021] [Indexed: 05/03/2023]
Abstract
Monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) are the main constituent lipids of thylakoid and chloroplast envelop membranes. Many microalgae can accumulate large amounts of triacylglycerols (TAGs) under adverse environmental conditions, which is accompanied by degradation of the photosynthetic membrane lipids. However, the process mediating the conversion from galactolipids to TAG remains largely unknown. In this study, we performed genetic and biochemical analyses of galactosyl hydrolases (CrGH) identified in the proteome of lipid bodies of the green microalga Chlamydomonas reinhardtii. The recombinant CrGH was confirmed to possess galactosyl hydrolase activity by using o-nitrophenyl-β-D-galactoside as the substrate, and the Michaelis constant (Km) and Kcat of CrGH were 13.98 μM and 3.62 s-1, respectively. Comparative lipidomic analyses showed that the content of MGDG and DGDG increased by 14.42% and 24.88%, respectively, in the CrGH-deficient mutant as compared with that of the wild type cc4533 grown under high light stress conditions, and meanwhile, the TAG content decreased by 32.20%. Up-regulation of CrGH at both a gene expression and protein level was observed under high light stress (HL) conditions. In addition, CrGH was detected in multiple subcellular localizations, including the chloroplast envelope, mitochondria, and endoplasmic reticulum membranes. This study uncovered a new paradigm mediated by the multi-localized CrGH for the conversion of the photosynthetic membranes to TAGs.
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Affiliation(s)
- Xiaosong Gu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; (X.G.); (L.C.); (X.W.); (Y.L.); (Q.H.)
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Li Cao
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; (X.G.); (L.C.); (X.W.); (Y.L.); (Q.H.)
| | - Xiaoying Wu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; (X.G.); (L.C.); (X.W.); (Y.L.); (Q.H.)
| | - Yanhua Li
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; (X.G.); (L.C.); (X.W.); (Y.L.); (Q.H.)
| | - Qiang Hu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; (X.G.); (L.C.); (X.W.); (Y.L.); (Q.H.)
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Danxiang Han
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; (X.G.); (L.C.); (X.W.); (Y.L.); (Q.H.)
- Correspondence:
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21
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Ma H, Wu X, Wei Z, Zhao L, Li Z, Liang Q, Zheng J, Wang Y, Li Y, Huang L, Hu Q, Han D. Functional divergence of diacylglycerol acyltransferases in the unicellular green alga Haematococcus pluvialis. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:510-524. [PMID: 33005924 PMCID: PMC7853605 DOI: 10.1093/jxb/eraa451] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 10/05/2020] [Indexed: 05/03/2023]
Abstract
Acyl-CoA:diacylglycerol acyltransferase (DGAT) catalyzes the final committed step in triacylglycerol biosynthesis in eukaryotes. In microalgae, the copy number of DGAT genes is extraordinarily expanded, yet the functions of many DGATs remain largely unknown. This study revealed that microalgal DGAT can function as a lysophosphatidic acyltransferase (LPAAT) both in vitro and in vivo while losing its original function as DGAT. Among the five DGAT-encoding genes identified and cloned from the green microalga Haematococcus pluvialis, four encoded HpDGATs that showed triacylglycerol synthase activities in yeast functional complementation analyses; the exception was one of the type II DGAT encoding genes, HpDGTT2. The hydrophobic recombinant HpDGTT2 protein was purified in soluble form and was found to function as a LPAAT via enzymatic assay. Introducing this gene into the green microalga Chlamydomonas reinhardtii led to retarded cellular growth, enlarged cell size, and enhanced triacylglycerol accumulation, identical to the phenotypes of transgenic strains overexpressing CrLPAAT. This study provides a framework for dissecting uncharacterized DGATs, and could pave the way to decrypting the structure-function relationship of this large group of enzymes that are critical to lipid biosynthesis.
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Affiliation(s)
- Haiyan Ma
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Xiaoying Wu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Ziwang Wei
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Department of Chemistry, The University of British Columbia, Vancouver, BC, Canada
| | - Liang Zhao
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Zhongze Li
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qing Liang
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Jie Zheng
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yu Wang
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Yanhua Li
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Linfei Huang
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qiang Hu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
- Beijing Key Laboratory of Algae Biomass, SDIC Biotech Investment Corporation, Beijing, China
- Correspondence: or
| | - Danxiang Han
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
- Correspondence: or
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Kato Y, Hasunuma T. Metabolic Engineering for Carotenoid Production Using Eukaryotic Microalgae and Prokaryotic Cyanobacteria. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1261:121-135. [PMID: 33783735 DOI: 10.1007/978-981-15-7360-6_10] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Eukaryotic microalgae and prokaryotic cyanobacteria are diverse photosynthetic organisms that produce various useful compounds. Due to their rapid growth and efficient biomass production from carbon dioxide and solar energy, microalgae and cyanobacteria are expected to become cost-effective, sustainable bioresources in the future. These organisms also abundantly produce various carotenoids, but further improvement in carotenoid productivity is needed for a successful commercialization. Metabolic engineering via genetic manipulation and mutational breeding is a powerful tool for generating carotenoid-rich strains. This chapter focuses on carotenoid production in microalgae and cyanobacteria, as well as strategies and potential target genes for metabolic engineering. Recent achievements in metabolic engineering that improved carotenoid production in microalgae and cyanobacteria are also reviewed.
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Affiliation(s)
- Yuichi Kato
- Graduate School of Science, Technology and Innovation, Kobe University, Kobe-city, Hyogo, Japan
| | - Tomohisa Hasunuma
- Graduate School of Science, Technology and Innovation, Kobe University, Kobe-city, Hyogo, Japan.
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Chungjatupornchai W, Fa-Aroonsawat S. Enhanced triacylglycerol production in oleaginous microalga Neochloris oleoabundans by co-overexpression of lipogenic genes: Plastidial LPAAT1 and ER-located DGAT2. J Biosci Bioeng 2020; 131:124-130. [PMID: 33069576 DOI: 10.1016/j.jbiosc.2020.09.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/18/2020] [Accepted: 09/18/2020] [Indexed: 12/29/2022]
Abstract
Microalgae accumulate lipid triacylglycerol (TAG), a promising feedstock for production of natural edible oils and biofuels. To make products derived from microalgal TAG economically viable, increasing TAG content and productivity are of high importance. To increase TAG content, two endogenous key enzymes of TAG biosynthesis: plastidial lysophosphatidic acid acyltransferase (NeoLPAAT1) and endoplasmic reticulum-located diacylglycerol acyltransferase 2 (NeoDGAT2) were co-overexpressed in oleaginous microalga Neochloris oleoabundans. The neutral lipid content in NeoLPAAT1-NeoDGAT2 co-overexpressing transformant detected by Nile red staining increased 2-fold without compromising cell growth. The transcriptional levels of NeoLPAAT1 and NeoDGAT2 levels were 1.9-fold higher in the transformant than wild type. Considerably higher lipid accumulation was found in the transformant than wild type: total lipid content (73.72 ± 4.17 % DCW) increased 1.6-fold, TAG content (50.63 ± 6.15 % DCW) increased 2.1-fold, total lipid productivity (16.84 ± 0.66 mg/L/day) increased 1.9-fold, and TAG productivity (11.68 ± 0.90 mg/L/day) increased 2.1-fold. Fatty acid composition was slightly altered in the transformant compared to wild type; saturated fatty acid C16:0 increased to 26% from 20%, whereas C18:0 was reduced to 7% from 14%. Long-term stability of NeoLPAAT1-NeoDGAT2 co-overexpression was observed in the transformant continuously maintained on solid medium in a period of 4 years. The results suggested that targeted engineering of genes in pathway located at different organelles should be possible in microalgal lipid metabolism.
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Affiliation(s)
- Wipa Chungjatupornchai
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakhon Pathom 73170, Thailand.
| | - Sirirat Fa-Aroonsawat
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakhon Pathom 73170, Thailand.
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Li Z, Cao L, Zhao L, Yu L, Chen Y, Yoon KS, Hu Q, Han D. Identification and Biotechnical Potential of a Gcn5-Related N-Acetyltransferase Gene in Enhancing Microalgal Biomass and Starch Production. FRONTIERS IN PLANT SCIENCE 2020; 11:544827. [PMID: 32983212 PMCID: PMC7483765 DOI: 10.3389/fpls.2020.544827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 08/12/2020] [Indexed: 06/11/2023]
Abstract
Microalgae are promising feedstocks for starch production, which are precursors for bioenergy and chemicals manufacturing. Though starch biosynthesis has been intensively studied in the green alga Chlamydomonas reinhardtii, regulatory mechanisms governing starch metabolism in this model species have remained largely unknown to date. We proposed that altering triacylglycerol (TAG) biosynthesis may trigger intrinsic regulatory pathways governing starch metabolism. In accordance with the hypothesis, it was observed in this study that overexpression of the plastidial lysophosphatidic acid acyltransferase gene (i.e. LPAAT1) in C. reinhardtii significantly enhanced TAG biosynthesis under nitrogen (N)-replete conditions, whereas the starch biosynthesis was enhanced in turn under N depletion. By the exploitation of transcriptomics analysis, a putative regulatory gene coding Gcn5-related N-acetyltransferase (GNAT19) was identified, which was up-regulated by 11-12 times in the CrLPAAT1 OE lines. Overexpression of the cloned full-length CrGNAT19 cDNA led to significant increase in the starch content of C. reinhardtii cells grown under both N-replete and N-depleted conditions, which was up to 4 times and 26.7% higher than that of the empty vector control, respectively. Moreover, the biomass yield of the CrGNAT19 OE lines reached 1.5 g L-1 after 2 days under N-depleted conditions, 72% higher than that of the empty vector control (0.87 g L-1). Overall, the yield of starch increased by 118.5% in CrGNAT19 OE lines compared to that of the control. This study revealed the great biotechnical potentials of an unprecedented GNAT19 gene in enhancing microalgal starch and biomass production.
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Affiliation(s)
- Zhongze Li
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Li Cao
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Liang Zhao
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Lihua Yu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Yi Chen
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Kang-sup Yoon
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Qiang Hu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Danxiang Han
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
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Jang S, Kong F, Lee J, Choi BY, Wang P, Gao P, Yamano T, Fukuzawa H, Kang BH, Lee Y. CrABCA2 Facilitates Triacylglycerol Accumulation in Chlamydomonas reinhardtii under Nitrogen Starvation. Mol Cells 2020; 43:48-57. [PMID: 31910336 PMCID: PMC6999713 DOI: 10.14348/molcells.2019.0262] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 11/30/2019] [Accepted: 12/02/2019] [Indexed: 11/27/2022] Open
Abstract
The microalga Chlamydomonas reinhardtii accumulates triacylglycerols (TAGs) in lipid droplets under stress conditions, such as nitrogen starvation. TAG biosynthesis occurs mainly at the endoplasmic reticulum (ER) and requires fatty acid (FA) substrates supplied from chloroplasts. How FAs are transferred from chloroplast to ER in microalgae was unknown. We previously reported that an Arabidopsis thaliana ATP-binding cassette (ABC) transporter, AtABCA9, facilitates FA transport at the ER during seed development. Here we identified a gene homologous to AtABCA9 in the C. reinhardtii genome, which we named CrABCA2. Under nitrogen deprivation conditions, CrABCA2 expression was upregulated, and the CrABCA2 protein level also increased. CrABCA2 knockdown lines accumulated less TAGs and CrABCA2 overexpression lines accumulated more TAGs than their untransformed parental lines. Transmission electron microscopy showed that CrABCA2 was localized in swollen ER. These results suggest that CrABCA2 transports substrates for TAG biosynthesis to the ER during nitrogen starvation . Our study provides a potential tool for increasing lipid production in microalgae.
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Affiliation(s)
- Sunghoon Jang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673,
Korea
| | - Fantao Kong
- School of Bioengineering, Dalian University of Technology, Dalian 116024,
China
| | - Jihyeon Lee
- Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37673,
Korea
| | - Bae Young Choi
- Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37673,
Korea
| | - Pengfei Wang
- Cellular and Molecular Biology Program, State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, New Territories, Hong Kong 999077,
China
| | - Peng Gao
- Cellular and Molecular Biology Program, State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, New Territories, Hong Kong 999077,
China
| | - Takashi Yamano
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502,
Japan
| | - Hideya Fukuzawa
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502,
Japan
| | - Byung-Ho Kang
- Cellular and Molecular Biology Program, State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, New Territories, Hong Kong 999077,
China
| | - Youngsook Lee
- Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37673,
Korea
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Vecchi V, Barera S, Bassi R, Dall’Osto L. Potential and Challenges of Improving Photosynthesis in Algae. PLANTS 2020; 9:plants9010067. [PMID: 31947868 PMCID: PMC7020468 DOI: 10.3390/plants9010067] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 12/24/2019] [Accepted: 12/30/2019] [Indexed: 11/16/2022]
Abstract
Sunlight energy largely exceeds the energy required by anthropic activities, and therefore its exploitation represents a major target in the field of renewable energies. The interest in the mass cultivation of green microalgae has grown in the last decades, as algal biomass could be employed to cover a significant portion of global energy demand. Advantages of microalgal vs. plant biomass production include higher light-use efficiency, efficient carbon capture and the valorization of marginal lands and wastewaters. Realization of this potential requires a decrease of the current production costs, which can be obtained by increasing the productivity of the most common industrial strains, by the identification of factors limiting biomass yield, and by removing bottlenecks, namely through domestication strategies aimed to fill the gap between the theoretical and real productivity of algal cultures. In particular, the light-to-biomass conversion efficiency represents one of the major constraints for achieving a significant improvement of algal cell lines. This review outlines the molecular events of photosynthesis, which regulate the conversion of light into biomass, and discusses how these can be targeted to enhance productivity through mutagenesis, strain selection or genetic engineering. This review highlights the most recent results in the manipulation of the fundamental mechanisms of algal photosynthesis, which revealed that a significant yield enhancement is feasible. Moreover, metabolic engineering of microalgae, focused upon the development of renewable fuel biorefineries, has also drawn attention and resulted in efforts for enhancing productivity of oil or isoprenoids.
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Affiliation(s)
| | | | | | - Luca Dall’Osto
- Correspondence: ; Tel.: +39-045-8027806; Fax: +39-045-8027929
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27
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Huang L, Yu L, Li Z, Li Y, Yoon KS, Hu Q, Yuan L, Han D. Microalgal plastidial lysophosphatidic acid acyltransferase interacts with upstream glycerol-3-phosphate acyltransferase and defines its substrate selectivity via the two transmembrane domains. ALGAL RES 2020. [DOI: 10.1016/j.algal.2019.101758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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28
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Genetic Engineering for Enhancement of Biofuel Production in Microalgae. CLEAN ENERGY PRODUCTION TECHNOLOGIES 2020. [DOI: 10.1007/978-981-15-9593-6_21] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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29
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Wang X, Liu SF, Li RY, Yang WD, Liu JS, Lin CSK, Balamurugan S, Li HY. TAG pathway engineering via GPAT2 concurrently potentiates abiotic stress tolerance and oleaginicity in Phaeodactylum tricornutum. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:160. [PMID: 32944076 PMCID: PMC7491103 DOI: 10.1186/s13068-020-01799-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 09/04/2020] [Indexed: 05/03/2023]
Abstract
BACKGROUND Despite the great potential of marine diatoms in biofuel sector, commercially viable biofuel production from native diatom strain is impractical. Targeted engineering of TAG pathway represents a promising approach; however, recruitment of potential candidate has been regarded as critical. Here, we identified a glycerol-3-phosphate acyltransferase 2 (GPAT2) isoform and overexpressed in Phaeodactylum tricornutum. RESULTS GPAT2 overexpression did not impair growth and photosynthesis. GPAT2 overexpression reduced carbohydrates and protein content, however, lipid content were significantly increased. Specifically, TAG content was notably increased by 2.9-fold than phospho- and glyco-lipids. GPAT2 overexpression elicited the push-and-pull strategy by increasing the abundance of substrates for the subsequent metabolic enzymes, thereby increased the expression of LPAAT and DGAT. Besides, GPAT2-mediated lipid overproduction coordinated the expression of NADPH biosynthetic genes. GPAT2 altered the fatty acid profile in TAGs with C16:0 as the predominant fatty acid moieties. We further investigated the impact of GPAT2 on conferring abiotic stress, which exhibited enhanced tolerance to hyposaline (70%) and chilling (10 ºC) conditions via altered fatty acid saturation level. CONCLUSIONS Collectively, our results exemplified the critical role of GPAT2 in hyperaccumulating TAGs with altered fatty acid profile, which in turn uphold resistance to abiotic stress conditions.
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Affiliation(s)
- Xiang Wang
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
| | - Si-Fen Liu
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
| | - Ruo-Yu Li
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
| | - Wei-Dong Yang
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
| | - Jie-Sheng Liu
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
| | - Carol Sze Ki Lin
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
| | - Srinivasan Balamurugan
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
- Department of Biotechnology, Bharathidasan University, Tiruchirappalli, 620024 India
| | - Hong-Ye Li
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
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Otaki R, Oishi Y, Abe S, Fujiwara S, Sato N. Regulatory carbon metabolism underlying seawater-based promotion of triacylglycerol accumulation in Chlorella kessleri. BIORESOURCE TECHNOLOGY 2019; 289:121686. [PMID: 31238290 DOI: 10.1016/j.biortech.2019.121686] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/03/2019] [Accepted: 06/18/2019] [Indexed: 06/09/2023]
Abstract
Chlorella kessleri accumulates triacylglycerol usable for biodiesel-fuel production to >20% dry cell weight in three days when cultured in three-fold diluted seawater, which imposes the combinatory stress of hyperosmosis and nutrients limitation. The quantitative behavior of major C-compounds, and related-gene expression patterns were investigated in Chlorella cells stressed with hyperosmosis, nutrients limitation, or their combination, to elucidate the C-metabolism for economical seawater-based triacylglycerol accumulation. Combinatory-stress cells showed repressed protein synthesis with initially accumulated starch being degraded later, the C-metabolic flow thereby being diverted to fatty acid and subsequent triacylglycerol accumulation. This C-flow diversion was induced by cooperative actions of nutrients-limitation and hyperosmosis. Semi-quantitative PCR analysis implied positive rewiring of the diverted C-flow into triacylglycerol in combinatory-stress cells through upregulation of gene expression concerning fatty acid and triacylglycerol synthesis, and starch synthesis and degradation. The information of regulatory C-metabolism will help reinforce the seawater-based triacylglycerol accumulation ability in algae including Chlorella.
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Affiliation(s)
- Rie Otaki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Yutaro Oishi
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Seiya Abe
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Shoko Fujiwara
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Norihiro Sato
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.
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Liu J, Sun Z, Mao X, Gerken H, Wang X, Yang W. Multiomics analysis reveals a distinct mechanism of oleaginousness in the emerging model alga Chromochloris zofingiensis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:1060-1077. [PMID: 30828893 DOI: 10.1111/tpj.14302] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 02/15/2019] [Accepted: 02/19/2019] [Indexed: 06/09/2023]
Abstract
Chromochloris zofingiensis, featured due to its capability to simultaneously synthesize triacylglycerol (TAG) and astaxanthin, is emerging as a leading candidate alga for production uses. To better understand the oleaginous mechanism of this alga, we conducted a multiomics analysis by systematically integrating time-resolved transcriptomes, lipidomes and metabolomes in response to nitrogen deprivation. The data analysis unraveled the distinct mechanism of TAG accumulation, which involved coordinated stimulation of multiple biological processes including supply of energy and reductants, carbon reallocation from protein and starch, and 'pushing' and 'pulling' carbon to TAG synthesis. Unlike the model alga Chlamydomonas, de novo fatty acid synthesis in C. zofingiensis was promoted, together with enhanced turnover of both glycolipids and phospholipids, supporting the drastic need of acyls for TAG assembly. Moreover, genomewide analysis identified many key functional enzymes and transcription factors that had engineering potential for TAG modulation. Two genes encoding glycerol-3-phosphate acyltransferase (GPAT), the first committed enzyme for TAG assembly, were found in the C. zofingiensis genome; in vivo functional characterization revealed that extrachloroplastic GPAT instead of chloroplastic GPAT played a central role in TAG synthesis. These findings illuminate distinct oleaginousness mechanisms in C. zofingiensis and pave the way towards rational manipulation of this alga to becone an emerging model for trait improvements.
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Affiliation(s)
- Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Zheng Sun
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
| | - Xuemei Mao
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Henri Gerken
- School of Sustainable Engineering and the Built Environment, Arizona State University Polytechnic campus, Mesa, AZ, 85212, USA
| | - Xiaofei Wang
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Wenqiang Yang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
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Kong F, Yamaoka Y, Ohama T, Lee Y, Li-Beisson Y. Molecular Genetic Tools and Emerging Synthetic Biology Strategies to Increase Cellular Oil Content in Chlamydomonas reinhardtii. PLANT & CELL PHYSIOLOGY 2019; 60:1184-1196. [PMID: 30715500 DOI: 10.1093/pcp/pcz022] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 01/18/2019] [Indexed: 05/26/2023]
Abstract
Microalgae constitute a highly diverse group of eukaryotic and photosynthetic microorganisms that have developed extremely efficient systems for harvesting and transforming solar energy into energy-rich molecules such as lipids. Although microalgae are considered to be one of the most promising platforms for the sustainable production of liquid oil, the oil content of these organisms is naturally low, and algal oil production is currently not economically viable. Chlamydomonas reinhardtii (Chlamydomonas) is an established algal model due to its fast growth, high transformation efficiency, and well-understood physiology and to the availability of detailed genome information and versatile molecular tools for this organism. In this review, we summarize recent advances in the development of genetic manipulation tools for Chlamydomonas, from gene delivery methods to state-of-the-art genome-editing technologies and fluorescent dye-based high-throughput mutant screening approaches. Furthermore, we discuss practical strategies and toolkits that enhance transgene expression, such as choice of expression vector and background strain. We then provide examples of how advanced genetic tools have been used to increase oil content in Chlamydomonas. Collectively, the current literature indicates that microalgal oil content can be increased by overexpressing key enzymes that catalyze lipid biosynthesis, blocking lipid degradation, silencing metabolic pathways that compete with lipid biosynthesis and modulating redox state. The tools and knowledge generated through metabolic engineering studies should pave the way for developing a synthetic biological approach to enhance lipid productivity in microalgae.
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Affiliation(s)
- Fantao Kong
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang, Korea
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, China
| | - Yasuyo Yamaoka
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang, Korea
| | - Takeshi Ohama
- School of Environmental Science and Engineering, Kochi University of Technology (KUT), Tosayamada, Kochi, Japan
| | - Youngsook Lee
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang, Korea
- Department of Life Science, Pohang University of Science and Technology, Pohang, Korea
| | - Yonghua Li-Beisson
- Aix-Marseille Univ., CEA, CNRS, BIAM, UMR7265, CEA Cadarache, Saint-Paul-lez Durance F, France
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Sun XM, Ren LJ, Zhao QY, Ji XJ, Huang H. Enhancement of lipid accumulation in microalgae by metabolic engineering. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:552-566. [DOI: 10.1016/j.bbalip.2018.10.004] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 07/30/2018] [Accepted: 10/05/2018] [Indexed: 01/08/2023]
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Chungjatupornchai W, Areerat K, Fa-Aroonsawat S. Increased triacylglycerol production in oleaginous microalga Neochloris oleoabundans by overexpression of plastidial lysophosphatidic acid acyltransferase. Microb Cell Fact 2019; 18:53. [PMID: 30866936 PMCID: PMC6415348 DOI: 10.1186/s12934-019-1104-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 03/08/2019] [Indexed: 11/17/2022] Open
Abstract
Background Microalgae are promising sources of lipid triacylglycerol (TAG) for sustainable production of natural edible oils and biofuels. Nevertheless, products derived from microalgal TAG are not yet economically feasible; increasing TAG content via targeted genetic engineering of genes in TAG biosynthesis pathway are important to achieve economic viability. To increase TAG content, oleaginous microalga Neochloris oleoabundans was genetically engineered with the endogenous enzyme lysophosphatidic acid acyltransferase (NeoLPAAT1) responsible for plastidial TAG biosynthesis Results NeoLPAAT1 was found to contain all canonical motifs attributed to LPAAT proteins, two hypothetical membrane-spanning domains and a putative chloroplast transit peptide, indicating as a member of plastidial LPAAT type 1 subfamily. The NeoLPAAT1-expression cassette integrated in N. oleoabundans transformant was confirmed by PCR. The neutral lipid content in the transformant detected by Nile red staining was 1.6-fold higher than in wild type. The NeoLPAAT1 transcript was twofold higher in the transformant than wild type. Considerably higher lipid quantity was found in the transformant than wild type: total lipid content increased 1.8- to 1.9-fold up to 78.99 ± 1.75% dry cell weight (DCW) and total lipid productivity increased 1.8- to 2.4-fold up to 16.06 ± 2.68 mg/L/day; while TAG content increased 2.1- to 2.2-fold up to 55.40 ± 5.56% DCW and TAG productivity increased 1.9- to 2.8-fold up to 10.67 ± 2.37 mg/L/day. A slightly altered fatty acid composition was detected in the transformant compared to wild type; polyunsaturated fatty acid (C18:2) increased to 19% from 11%. NeoLPAAT1-overexpression stability was observed in the transformant continuously maintained in solid medium over 150 generations in a period of about 6 years. Conclusions Our results demonstrate the considerably increased TAG content and productivity in N. oleoabundans by overexpression of plastidial NeoLPAAT1 that are important for products derived from microalgal TAG to achieve economic viability. Plastidial LPAAT1 can be a candidate for target genetic manipulation to increase TAG content in other microalgal species with desired characteristics for production of natural edible oils and biofuels.
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Affiliation(s)
- Wipa Chungjatupornchai
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Phutthamonthon, Nakhon Pathom, 73170, Thailand.
| | - Kanchanaporn Areerat
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Phutthamonthon, Nakhon Pathom, 73170, Thailand
| | - Sirirat Fa-Aroonsawat
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Phutthamonthon, Nakhon Pathom, 73170, Thailand
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Li-Beisson Y, Thelen JJ, Fedosejevs E, Harwood JL. The lipid biochemistry of eukaryotic algae. Prog Lipid Res 2019; 74:31-68. [PMID: 30703388 DOI: 10.1016/j.plipres.2019.01.003] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 02/06/2023]
Abstract
Algal lipid metabolism fascinates both scientists and entrepreneurs due to the large diversity of fatty acyl structures that algae produce. Algae have therefore long been studied as sources of genes for novel fatty acids; and, due to their superior biomass productivity, algae are also considered a potential feedstock for biofuels. However, a major issue in a commercially viable "algal oil-to-biofuel" industry is the high production cost, because most algal species only produce large amounts of oils after being exposed to stress conditions. Recent studies have therefore focused on the identification of factors involved in TAG metabolism, on the subcellular organization of lipid pathways, and on interactions between organelles. This has been accompanied by the development of genetic/genomic and synthetic biological tools not only for the reference green alga Chlamydomonas reinhardtii but also for Nannochloropsis spp. and Phaeodactylum tricornutum. Advances in our understanding of enzymes and regulatory proteins of acyl lipid biosynthesis and turnover are described herein with a focus on carbon and energetic aspects. We also summarize how changes in environmental factors can impact lipid metabolism and describe present and potential industrial uses of algal lipids.
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Affiliation(s)
- Yonghua Li-Beisson
- Aix-Marseille Univ, CEA, CNRS, BIAM, UMR7265, CEA Cadarache, Saint-Paul-lez Durance F-13108, France.
| | - Jay J Thelen
- Department of Biochemistry, University of Missouri, Christopher S. Bond Life Sciences Center, Columbia, MO 65211, United States.
| | - Eric Fedosejevs
- Department of Biochemistry, University of Missouri, Christopher S. Bond Life Sciences Center, Columbia, MO 65211, United States.
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK.
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Muñoz CF, Weusthuis RA, D’Adamo S, Wijffels RH. Effect of Single and Combined Expression of Lysophosphatidic Acid Acyltransferase, Glycerol-3-Phosphate Acyltransferase, and Diacylglycerol Acyltransferase on Lipid Accumulation and Composition in Neochloris oleoabundans. FRONTIERS IN PLANT SCIENCE 2019; 10:1573. [PMID: 31850043 PMCID: PMC6895027 DOI: 10.3389/fpls.2019.01573] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 11/11/2019] [Indexed: 05/03/2023]
Abstract
Microalgal lipids are promising feedstocks for food and biofuels. Since lipid production by microalgae is not yet economically feasible, genetic engineering is becoming a promising strategy to achieve higher lipid accumulation and productivities. Enzymes involved in the Kennedy pathway such as glycerol-3-phosphate acyltransferase (GPAT), lysophosphatidic acid acyltransferase (LPAT), and diacylglycerol acyltransferase (DGAT) catalyze key steps in the formation of triacylglycerol, which is the main constituent of lipids in N. oleoabundans. The overexpression of these enzymes in the targeted strain has a great potential to further increase their triacylglycerol content. We overexpressed single and multiple encoding genes for LPAT, GPAT, and DGAT from Acutodesmus obliquus in N. oleoabundans. Strains overexpressing single genes produced up to 52% and 45% g · gDW-1, which corresponds to 1.3- and 1.4-fold increase in total fatty acids and triacylglycerols, respectively. The orchestrated expression of the three genes resulted in 49% and 39% g · gDW-1, which is 1.2-folds increase in total fatty acids and triacylglycerols. Single expression of LPAT, GPAT, and DGAT genes resulted in higher lipid productivities during starvation without a significant effect on growth and photosynthetic activity during replete conditions. On the other hand, the simultaneous expression of LPAT, GPAT, and DGAT genes resulted in 52% lower growth rate, 14% lower photosynthetic activity and 4-folds increase in cell diameter. Moreover, the multigene expressing line showed a decrease in carbohydrates and protein content and an increase in pigments during nitrogen starved condition. The single and multiple expression of heterologous genes LPAT, GPAT, and DGAT showed to significantly enhanced the lipid accumulation in N. oleoabundans. Single gene expression resulted in higher lipid production and productivities without having a significant impact in the physiological status of the strains. This approach shows the potential for the generation of microalgal strains with higher economical potential for the production of lipids.
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Affiliation(s)
- Camilo F. Muñoz
- Bioprocess Engineering, Wageningen University and Research, Wageningen, Netherlands
- *Correspondence: Camilo F. Muñoz,
| | - Ruud A. Weusthuis
- Bioprocess Engineering, Wageningen University and Research, Wageningen, Netherlands
| | - Sarah D’Adamo
- Bioprocess Engineering, Wageningen University and Research, Wageningen, Netherlands
| | - René H. Wijffels
- Bioprocess Engineering, Wageningen University and Research, Wageningen, Netherlands
- Biosciences and Aquaculture, Nord University, Bodø, Norway
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Jia B, Xie X, Wu M, Lin Z, Yin J, lou S, Huang Y, Hu Z. Understanding the functions of endogenous DOF transcript factor in Chlamydomonas reinhardtii. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:67. [PMID: 30972144 PMCID: PMC6436238 DOI: 10.1186/s13068-019-1403-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 03/11/2019] [Indexed: 05/03/2023]
Abstract
BACKGROUND The regulation of genes related to lipid metabolism by genetic engineering is an important way to increase the accumulation of lipids in microalgae. DNA binding with one finger (DOF) is a plant-specific transcription factor in higher plants, where it regulates carbon and nitrogen metabolic pathways by regulating key genes involved in these pathways. Overexpression of DOF can increase lipid production in plants; however, it is not clear whether overexpression of DOF can increase lipids in microalgae. RESULTS In this study, we cloned a DOF transcription factor, crDOF, from Chlamydomonas reinhardtii. The sequence of this transcription factor is 1875 bp and encodes a peptide of 624 amino acids with a conserved DOF domain. Overexpression of crDOF in C. reinhardtii significantly increased the intracellular lipid content. The content of total fatty acids in the transgenic algae line Tranc-crDOF-12 was 126.01 μg/mg (dry weight), which was 23.24% higher than that of the wild type. Additionally, the content of unsaturated fatty acids in the transgenic Tranc-crDOF-12 line increased significantly. Fluorescence quantitative PCR analysis showed that in the transgenic line Tranc-crDOF-12, the expression levels of BCC1, FAT1, SQD1, MGD1, DGD1 and PGP1 genes were significantly upregulated, while the expression levels of ACP1, ACS1, CIS1 and SQD2 were downregulated. CONCLUSIONS Our results confirm that crDOF increases intracellular lipids in C. reinhardtii by regulating key genes involved in lipid metabolism. According to these findings, we propose that enhancing the lipid content in microalgae by overexpressing DOF may be achieved in other industrial strains of microalgae and be employed for the industrial production of biodiesel.
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Affiliation(s)
- Bin Jia
- Guangdong Engineering Research Center for Marine Algal Biotechnology,
Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Longhua Innovation Institute for Biotechnology, College of Life Sciences, Shenzhen University, Shenzhen, 518060 People’s Republic of China
| | - Xinfeng Xie
- Guangdong Engineering Research Center for Marine Algal Biotechnology,
Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Longhua Innovation Institute for Biotechnology, College of Life Sciences, Shenzhen University, Shenzhen, 518060 People’s Republic of China
| | - Min Wu
- Guangdong Engineering Research Center for Marine Algal Biotechnology,
Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Longhua Innovation Institute for Biotechnology, College of Life Sciences, Shenzhen University, Shenzhen, 518060 People’s Republic of China
| | - Zijie Lin
- Guangdong Engineering Research Center for Marine Algal Biotechnology,
Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Longhua Innovation Institute for Biotechnology, College of Life Sciences, Shenzhen University, Shenzhen, 518060 People’s Republic of China
| | - Jianbo Yin
- Guangdong Engineering Research Center for Marine Algal Biotechnology,
Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Longhua Innovation Institute for Biotechnology, College of Life Sciences, Shenzhen University, Shenzhen, 518060 People’s Republic of China
| | - Sulin lou
- Guangdong Engineering Research Center for Marine Algal Biotechnology,
Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Longhua Innovation Institute for Biotechnology, College of Life Sciences, Shenzhen University, Shenzhen, 518060 People’s Republic of China
| | - Ying Huang
- Guangdong Engineering Research Center for Marine Algal Biotechnology,
Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Longhua Innovation Institute for Biotechnology, College of Life Sciences, Shenzhen University, Shenzhen, 518060 People’s Republic of China
| | - Zhangli Hu
- Guangdong Engineering Research Center for Marine Algal Biotechnology,
Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Longhua Innovation Institute for Biotechnology, College of Life Sciences, Shenzhen University, Shenzhen, 518060 People’s Republic of China
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38
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Naghshbandi MP, Tabatabaei M, Aghbashlo M, Aftab MN, Iqbal I. Metabolic Engineering of Microalgae for Biofuel Production. Methods Mol Biol 2019; 1980:153-172. [PMID: 30666564 DOI: 10.1007/7651_2018_205] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Microalgae are considered as promising cell factories for the production of various types of biofuels, including bioethanol, biodiesel, and biohydrogen by using carbon dioxide and sunlight. In spite of unique advantages of these microorganisms, the commercialization of microalgal biofuels has been hindered by poor economic features. Metabolic engineering is among the most promising strategies put forth to overcome this challenge. In this chapter, metabolic pathways involved in lipid and hydrogen production by microalgae are reviewed and discussed. Moreover, metabolic and genetic engineering approaches investigated for improving the rate of lipid (as a feedstock for biodiesel production) and biohydrogen synthesis are presented. Finally, genetic engineering tools and approaches employed for engineering microalgal metabolic pathways are elaborated. A thorough step-by-step protocol for reconstructing the metabolic pathway of various microorganisms including microalgae is also presented.
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Affiliation(s)
- Mohammad Pooya Naghshbandi
- Department of Microbial Biotechnology, School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Meisam Tabatabaei
- Microbial Biotechnology Department, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research, Education, and Extension Organization (AREEO), Karaj, Iran. .,Biofuel Research Team (BRTeam), Karaj, Iran.
| | - Mortaza Aghbashlo
- Department of Mechanical Engineering of Agricultural Machinery, Faculty of Agricultural Engineering and Technology, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran.
| | - Muhammad Nauman Aftab
- Institute of Industrial Biotechnology, Government College University, Lahore, Pakistan
| | - Irfana Iqbal
- Department of Zoology, Lahore College for Women University, Lahore, Pakistan
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Yang M, Meng Y, Chu Y, Fan Y, Cao X, Xue S, Chi Z. Triacylglycerol accumulates exclusively outside the chloroplast in short-term nitrogen-deprived Chlamydomonas reinhardtii. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:1478-1487. [PMID: 30266428 DOI: 10.1016/j.bbalip.2018.09.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Revised: 08/25/2018] [Accepted: 09/23/2018] [Indexed: 01/13/2023]
Abstract
In microalgae, triacylglycerol (TAG) biosynthesis occurs by parallel pathways involving both the chloroplast and endoplasmic reticulum. A better understanding of contribution of each pathway to TAG assembly facilitates enhanced TAG production via rational genetic engineering of microalgae. Here, using a UPLC-MS(/MS) coupled with TLC-GC-based lipidomic platform, the early response of the major glycerolipids to nitrogen stress was analyzed at both the cellular and chloroplastidic levels in the model green alga Chlamydomonas reinhardtii. Subcellular lipidomic analysis demonstrated that TAG was accumulated exclusively outside the chloroplast, and remained unaltered inside the chloroplast after 4 h of nitrogen starvation. This study ascertained the existence of the glycolipid, digalactosyldiacylglycerol (DGDG), outside the chloroplast and the betaine lipid, diacylglycerol-N,N,N-trimethylhomoserine (DGTS), inside the chloroplast. The newly synthesized DGDG and DGTS prominently increased at the extra-chloroplastidic compartments and served as the major precursors for TAG biosynthesis. In particular, DGDG contributed to the extra-chloroplastidic TAG assembly in form of diacylglycerol (DAG) and DGTS in form of acyl groups. The chloroplastidic membrane lipid, monogalactosyldiacylglycerol (MGDG), was proposed to primarily offer DAG for TAG formation outside the chloroplast. This study provides valuable insights into the subcellular glycerolipidomics and unveils the acyl flux into the extra-chloroplastidic TAG in microalgae.
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Affiliation(s)
- Miao Yang
- Marine Bioengineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; University of Chinese Academy of Sciences, Beijing 100049, China; School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China.
| | - Yingying Meng
- Marine Bioengineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Yadong Chu
- Marine Bioengineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
| | - Yan Fan
- Marine Bioengineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Xupeng Cao
- Marine Bioengineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
| | - Song Xue
- Marine Bioengineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
| | - Zhanyou Chi
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China.
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40
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Rengel R, Smith RT, Haslam RP, Sayanova O, Vila M, León R. Overexpression of acetyl-CoA synthetase (ACS) enhances the biosynthesis of neutral lipids and starch in the green microalga Chlamydomonas reinhardtii. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.02.009] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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41
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Endoplasmic reticulum acyltransferase with prokaryotic substrate preference contributes to triacylglycerol assembly in Chlamydomonas. Proc Natl Acad Sci U S A 2018; 115:1652-1657. [PMID: 29382746 DOI: 10.1073/pnas.1715922115] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Understanding the unique features of triacylglycerol (TAG) metabolism in microalgae may be necessary to realize the full potential of these organisms for biofuel and biomaterial production. In the unicellular green alga Chlamydomonas reinhardtii a chloroplastic (prokaryotic) pathway has been proposed to play a major role in TAG precursor biosynthesis. However, as reported here, C. reinhardtii contains a chlorophyte-specific lysophosphatidic acid acyltransferase, CrLPAAT2, that localizes to endoplasmic reticulum (ER) membranes. Unlike canonical, ER-located LPAATs, CrLPAAT2 prefers palmitoyl-CoA over oleoyl-CoA as the acyl donor substrate. RNA-mediated suppression of CrLPAAT2 indicated that the enzyme is required for TAG accumulation under nitrogen deprivation. Our findings suggest that Chlamydomonas has a distinct glycerolipid assembly pathway that relies on CrLPAAT2 to generate prokaryotic-like TAG precursors in the ER.
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42
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Wang X, Dong HP, Wei W, Balamurugan S, Yang WD, Liu JS, Li HY. Dual expression of plastidial GPAT1 and LPAT1 regulates triacylglycerol production and the fatty acid profile in Phaeodactylum tricornutum. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:318. [PMID: 30479663 PMCID: PMC6249879 DOI: 10.1186/s13068-018-1317-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 11/13/2018] [Indexed: 05/03/2023]
Abstract
BACKGROUND Metabolic engineering has emerged as a potential strategy for improving microalgal lipid content through targeted changes to lipid metabolic networks. However, the intricate nature of lipogenesis has impeded metabolic engineering. Therefore, it is very important to identify the crucial metabolic nodes and develop strategies to exploit multiple genes for transgenesis. In an attempt to unravel the microalgal triacylglycerol (TAG) pathway, we overexpressed two key lipogenic genes, glycerol-3-phosphate acyltransferase (GPAT1) and lysophosphatidic acid acyltransferase (LPAT1), in oleaginous Phaeodactylum tricornutum and determined their roles in microalgal lipogenesis. RESULTS Engineered P. tricornutum strains showed enhanced growth and photosynthetic efficiency compared with that of the wild-type during the growth phase of the cultivation period. However, both the cell types reached stationary phase on day 7. Overexpression of GPAT1 and LPAT1 increased the TAG content by 2.3-fold under nitrogen-replete conditions without compromising cell growth, and they also orchestrated the expression of other key genes involved in TAG synthesis. The transgenic expression of GPAT1 and LPAT1 influenced the expression of malic enzyme and glucose 6-phosphate dehydrogenase, which enhanced the levels of lipogenic NADPH in the transgenic lines. In addition, GPAT1 and LPAT1 preferred C16 over C18 at the sn-2 position of the glycerol backbone. CONCLUSION Overexpression of GPAT1 together with LPAT1 significantly enhanced lipid content without affecting growth and photosynthetic efficiency, and they orchestrated the expression of other key photosynthetic and lipogenic genes. The lipid profile for elevated fatty acid content (C16-CoA) demonstrated the involvement of the prokaryotic TAG pathway in marine diatoms. The results suggested that engineering dual metabolic nodes should be possible in microalgal lipid metabolism. This study also provides the first demonstration of the role of the prokaryotic TAG biosynthetic pathway in lipid overproduction and indicates that the fatty acid profile can be tailored to improve lipid production.
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Affiliation(s)
- Xiang Wang
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
| | - Hong-Po Dong
- School of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang, 524088 China
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062 China
| | - Wei Wei
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
| | - Srinivasan Balamurugan
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
| | - Wei-Dong Yang
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
| | - Jie-Sheng Liu
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
| | - Hong-Ye Li
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
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43
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Razzak MA, Lee DW, Yoo YJ, Hwang I. Evolution of rubisco complex small subunit transit peptides from algae to plants. Sci Rep 2017; 7:9279. [PMID: 28839179 PMCID: PMC5571161 DOI: 10.1038/s41598-017-09473-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 07/26/2017] [Indexed: 11/09/2022] Open
Abstract
Chloroplasts evolved from a free-living cyanobacterium acquired by the ancestor of all photosynthetic eukaryotes, including algae and plants, through a single endosymbiotic event. During endosymbiotic conversion, the majority of genes in the endosymbiont were transferred to the host nucleus and many of the proteins encoded by these genes must therefore be transported into the chloroplast after translation in the cytosol. Chloroplast-targeted proteins contain a targeting signal, named the transit peptide (TP), at the N-terminus. However, the evolution of TPs is not well understood. In this study, TPs from RbcS (rubisco small subunit) were compared between lower and higher eukaryotes. Chlamydomonas reinhardtii RbcS (CrRbcS) TP was non-functional in Arabidopsis. However, inclusion of a critical sequence motif, FP-RK, from Arabidopsis thaliana RbcS (AtRbcS) TP allowed CrRbcS TP to deliver proteins into plant chloroplasts. The position of the FP-RK motif in CrRbcS TP was critical for function. The QMMVW sequence motif in CrRbcS TP was crucial for its transport activity in plants. CrRbcS TPs containing additional plant motifs remained functional in C. reinhardtii. These results suggest that TPs evolved by acquiring additional sequence motifs to support protein targeting to chloroplasts during evolution of land plants from algae.
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Affiliation(s)
- Md Abdur Razzak
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Dong Wook Lee
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Yun-Joo Yoo
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Inhwan Hwang
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, 37673, Korea.
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Driver T, Trivedi DK, McIntosh OA, Dean AP, Goodacre R, Pittman JK. Two Glycerol-3-Phosphate Dehydrogenases from Chlamydomonas Have Distinct Roles in Lipid Metabolism. PLANT PHYSIOLOGY 2017; 174:2083-2097. [PMID: 28588114 PMCID: PMC5543956 DOI: 10.1104/pp.17.00491] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 06/04/2017] [Indexed: 05/03/2023]
Abstract
The metabolism of glycerol-3-phosphate (G3P) is important for environmental stress responses by eukaryotic microalgae. G3P is an essential precursor for glycerolipid synthesis and the accumulation of triacylglycerol (TAG) in response to nutrient starvation. G3P dehydrogenase (GPDH) mediates G3P synthesis, but the roles of specific GPDH isoforms are currently poorly understood. Of the five GPDH enzymes in the model alga Chlamydomonas reinhardtii, GPD2 and GPD3 were shown to be induced by nutrient starvation and/or salt stress. Heterologous expression of GPD2, a putative chloroplastic GPDH, and GPD3, a putative cytosolic GPDH, in a yeast gpd1Δ mutant demonstrated the functionality of both enzymes. C. reinhardtii knockdown mutants for GPD2 and GPD3 showed no difference in growth but displayed significant reduction in TAG concentration compared with the wild type in response to phosphorus or nitrogen starvation. Overexpression of GPD2 and GPD3 in C. reinhardtii gave distinct phenotypes. GPD2 overexpression lines showed only subtle metabolic phenotypes and no significant alteration in growth. In contrast, GPD3 overexpression lines displayed significantly inhibited growth and chlorophyll concentration, reduced glycerol concentration, and changes to lipid composition compared with the wild type, including increased abundance of phosphatidic acids but reduced abundance of diglycerides, triglycerides, and phosphatidylglycerol lipids. This may indicate a block in the downstream glycerolipid metabolism pathway in GPD3 overexpression lines. Thus, lipid engineering by GPDH modification may depend on the activities of other downstream enzyme steps. These results also suggest that GPD2 and GPD3 GPDH isoforms are important for nutrient starvation-induced TAG accumulation but have distinct metabolic functions.
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Affiliation(s)
- Thomas Driver
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Drupad K Trivedi
- Manchester Institute of Biotechnology, School of Chemistry, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Owen A McIntosh
- School of Earth and Environmental Sciences, Faculty of Science and Engineering, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Andrew P Dean
- School of Science and the Environment, Faculty of Science and Engineering, Manchester Metropolitan University, Manchester M1 5GD, United Kingdom
| | - Royston Goodacre
- Manchester Institute of Biotechnology, School of Chemistry, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Jon K Pittman
- School of Earth and Environmental Sciences, Faculty of Science and Engineering, University of Manchester, Manchester M13 9PT, United Kingdom
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45
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Degraeve-Guilbault C, Bréhélin C, Haslam R, Sayanova O, Marie-Luce G, Jouhet J, Corellou F. Glycerolipid Characterization and Nutrient Deprivation-Associated Changes in the Green Picoalga Ostreococcus tauri. PLANT PHYSIOLOGY 2017; 173:2060-2080. [PMID: 28235892 PMCID: PMC5373045 DOI: 10.1104/pp.16.01467] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 02/23/2017] [Indexed: 05/23/2023]
Abstract
The picoalga Ostreococcus tauri is a minimal photosynthetic eukaryote that has been used as a model system. O. tauri is known to efficiently produce docosahexaenoic acid (DHA). We provide a comprehensive study of the glycerolipidome of O. tauri and validate this species as model for related picoeukaryotes. O. tauri lipids displayed unique features that combined traits from the green and the chromalveolate lineages. The betaine lipid diacylglyceryl-hydroxymethyl-trimethyl-β-alanine and phosphatidyldimethylpropanethiol, both hallmarks of chromalveolates, were identified as presumed extraplastidial lipids. DHA was confined to these lipids, while plastidial lipids of prokaryotic type were characterized by the overwhelming presence of ω-3 C18 polyunsaturated fatty acids (FAs), 18:5 being restricted to galactolipids. C16:4, an FA typical of green microalgae galactolipids, also was a major component of O. tauri extraplastidial lipids, while the 16:4-coenzyme A (CoA) species was not detected. Triacylglycerols (TAGs) displayed the complete panel of FAs, and many species exhibited combinations of FAs diagnostic for plastidial and extraplastidial lipids. Importantly, under nutrient deprivation, 16:4 and ω-3 C18 polyunsaturated FAs accumulated into de novo synthesized TAGs while DHA-TAG species remained rather stable, indicating an increased contribution of FAs of plastidial origin to TAG synthesis. Nutrient deprivation further severely down-regulated the conversion of 18:3 to 18:4, resulting in obvious inversion of the 18:3/18:4 ratio in plastidial lipids, TAGs, as well as acyl-CoAs. The fine-tuned and dynamic regulation of the 18:3/18:4 ratio suggested an important physiological role of these FAs in photosynthetic membranes. Acyl position in structural and storage lipids together with acyl-CoA analysis further help to determine mechanisms possibly involved in glycerolipid synthesis.
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Affiliation(s)
- Charlotte Degraeve-Guilbault
- Laboratoire de Biogenèse Membranaire, Unité Mixte de Recherche 5200, Centre National de la Recherche Scientifique, Université de Bordeaux BP81, F-33882 Villenave D'Ornon, France (C.D.-G., C.B., G.M.-L., F.C.)
- Rothamsted Research, Biological, Chemistry, Harpenden AL5 2JQ, United Kingdom (R.H., O.S.); and
- Laboratoire de Biologie Cellulaire et Végétale, Unité Mixte de Recherche 5168, Centre National de la Recherche Scientifique, Commissariat à l'Energie Atomique, Institut National de la Recherche Agronomique, Université Grenoble Alpes, BIG, Commissariat à l'Energie Atomique-Grenoble, 38054 Grenoble cedex 9, France (J.J.)
| | - Claire Bréhélin
- Laboratoire de Biogenèse Membranaire, Unité Mixte de Recherche 5200, Centre National de la Recherche Scientifique, Université de Bordeaux BP81, F-33882 Villenave D'Ornon, France (C.D.-G., C.B., G.M.-L., F.C.)
- Rothamsted Research, Biological, Chemistry, Harpenden AL5 2JQ, United Kingdom (R.H., O.S.); and
- Laboratoire de Biologie Cellulaire et Végétale, Unité Mixte de Recherche 5168, Centre National de la Recherche Scientifique, Commissariat à l'Energie Atomique, Institut National de la Recherche Agronomique, Université Grenoble Alpes, BIG, Commissariat à l'Energie Atomique-Grenoble, 38054 Grenoble cedex 9, France (J.J.)
| | - Richard Haslam
- Laboratoire de Biogenèse Membranaire, Unité Mixte de Recherche 5200, Centre National de la Recherche Scientifique, Université de Bordeaux BP81, F-33882 Villenave D'Ornon, France (C.D.-G., C.B., G.M.-L., F.C.)
- Rothamsted Research, Biological, Chemistry, Harpenden AL5 2JQ, United Kingdom (R.H., O.S.); and
- Laboratoire de Biologie Cellulaire et Végétale, Unité Mixte de Recherche 5168, Centre National de la Recherche Scientifique, Commissariat à l'Energie Atomique, Institut National de la Recherche Agronomique, Université Grenoble Alpes, BIG, Commissariat à l'Energie Atomique-Grenoble, 38054 Grenoble cedex 9, France (J.J.)
| | - Olga Sayanova
- Laboratoire de Biogenèse Membranaire, Unité Mixte de Recherche 5200, Centre National de la Recherche Scientifique, Université de Bordeaux BP81, F-33882 Villenave D'Ornon, France (C.D.-G., C.B., G.M.-L., F.C.)
- Rothamsted Research, Biological, Chemistry, Harpenden AL5 2JQ, United Kingdom (R.H., O.S.); and
- Laboratoire de Biologie Cellulaire et Végétale, Unité Mixte de Recherche 5168, Centre National de la Recherche Scientifique, Commissariat à l'Energie Atomique, Institut National de la Recherche Agronomique, Université Grenoble Alpes, BIG, Commissariat à l'Energie Atomique-Grenoble, 38054 Grenoble cedex 9, France (J.J.)
| | - Glawdys Marie-Luce
- Laboratoire de Biogenèse Membranaire, Unité Mixte de Recherche 5200, Centre National de la Recherche Scientifique, Université de Bordeaux BP81, F-33882 Villenave D'Ornon, France (C.D.-G., C.B., G.M.-L., F.C.)
- Rothamsted Research, Biological, Chemistry, Harpenden AL5 2JQ, United Kingdom (R.H., O.S.); and
- Laboratoire de Biologie Cellulaire et Végétale, Unité Mixte de Recherche 5168, Centre National de la Recherche Scientifique, Commissariat à l'Energie Atomique, Institut National de la Recherche Agronomique, Université Grenoble Alpes, BIG, Commissariat à l'Energie Atomique-Grenoble, 38054 Grenoble cedex 9, France (J.J.)
| | - Juliette Jouhet
- Laboratoire de Biogenèse Membranaire, Unité Mixte de Recherche 5200, Centre National de la Recherche Scientifique, Université de Bordeaux BP81, F-33882 Villenave D'Ornon, France (C.D.-G., C.B., G.M.-L., F.C.)
- Rothamsted Research, Biological, Chemistry, Harpenden AL5 2JQ, United Kingdom (R.H., O.S.); and
- Laboratoire de Biologie Cellulaire et Végétale, Unité Mixte de Recherche 5168, Centre National de la Recherche Scientifique, Commissariat à l'Energie Atomique, Institut National de la Recherche Agronomique, Université Grenoble Alpes, BIG, Commissariat à l'Energie Atomique-Grenoble, 38054 Grenoble cedex 9, France (J.J.)
| | - Florence Corellou
- Laboratoire de Biogenèse Membranaire, Unité Mixte de Recherche 5200, Centre National de la Recherche Scientifique, Université de Bordeaux BP81, F-33882 Villenave D'Ornon, France (C.D.-G., C.B., G.M.-L., F.C.);
- Rothamsted Research, Biological, Chemistry, Harpenden AL5 2JQ, United Kingdom (R.H., O.S.); and
- Laboratoire de Biologie Cellulaire et Végétale, Unité Mixte de Recherche 5168, Centre National de la Recherche Scientifique, Commissariat à l'Energie Atomique, Institut National de la Recherche Agronomique, Université Grenoble Alpes, BIG, Commissariat à l'Energie Atomique-Grenoble, 38054 Grenoble cedex 9, France (J.J.)
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Cline SG, Laughbaum IA, Hamel PP. CCS2, an Octatricopeptide-Repeat Protein, Is Required for Plastid Cytochrome c Assembly in the Green Alga Chlamydomonas reinhardtii. FRONTIERS IN PLANT SCIENCE 2017. [PMID: 28824661 DOI: 10.3389/fpls.2017.0130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
In bacteria and energy generating organelles, c-type cytochromes are a class of universal electron carriers with a heme cofactor covalently linked via one or two thioether bonds to a heme binding site. The covalent attachment of heme to apocytochromes is a catalyzed process, taking place via three evolutionarily distinct assembly pathways (Systems I, II, III). System II was discovered in the green alga Chlamydomonas reinhardtii through the genetic analysis of the ccs mutants (cytochrome csynthesis), which display a block in the apo- to holo- form conversion of cytochrome f and c6, the thylakoid lumen resident c-type cytochromes functioning in photosynthesis. Here we show that the gene corresponding to the CCS2 locus encodes a 1,719 amino acid polypeptide and identify the molecular lesions in the ccs2-1 to ccs2-5 alleles. The CCS2 protein displays seven degenerate amino acid repeats, which are variations of the octatricopeptide-repeat motif (OPR) recently recognized in several nuclear-encoded proteins controlling the maturation, stability, or translation of chloroplast transcripts. A plastid site of action for CCS2 is inferred from the finding that GFP fused to the first 100 amino acids of the algal protein localizes to chloroplasts in Nicotiana benthamiana. We discuss the possible functions of CCS2 in the heme attachment reaction.
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Affiliation(s)
- Sara G Cline
- Department of Molecular Genetics and Department of Biological Chemistry and Pharmacology, The Ohio State University, ColumbusOH, United States
- Plant Cellular and Molecular Biology Graduate Program, The Ohio State University, ColumbusOH, United States
| | - Isaac A Laughbaum
- Department of Molecular Genetics and Department of Biological Chemistry and Pharmacology, The Ohio State University, ColumbusOH, United States
| | - Patrice P Hamel
- Department of Molecular Genetics and Department of Biological Chemistry and Pharmacology, The Ohio State University, ColumbusOH, United States
- Plant Cellular and Molecular Biology Graduate Program, The Ohio State University, ColumbusOH, United States
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Balamurugan S, Wang X, Wang HL, An CJ, Li H, Li DW, Yang WD, Liu JS, Li HY. Occurrence of plastidial triacylglycerol synthesis and the potential regulatory role of AGPAT in the model diatom Phaeodactylum tricornutum. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:97. [PMID: 28435443 PMCID: PMC5397801 DOI: 10.1186/s13068-017-0786-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 04/11/2017] [Indexed: 05/02/2023]
Abstract
BACKGROUND Microalgae have emerged as a potential feedstock for biofuels and bioactive components. However, lack of microalgal strains with promising triacylglycerol (TAG) content and desirable fatty acid composition have hindered its commercial feasibility. Attempts on lipid overproduction by metabolic engineering remain largely challenging in microalgae. RESULTS In this study, a microalgal 1-acyl-sn-glycerol-3-phosphate acyltransferase designated AGPAT1 was identified in the model diatom Phaeodactylum tricornutum. AGPAT1 contained four conserved acyltransferase motifs I-IV. Subcellular localization prediction and thereafter immuno-electron microscopy revealed the localization of AGPAT1 to plastid membranes. AGPAT1 overexpression significantly altered the primary metabolism, with increased total lipid content but decreased content of total carbohydrates and soluble proteins. Intriguingly, AGPAT1 overexpression coordinated the expression of other key genes such as DGAT2 and GPAT involved in TAG synthesis, and consequently increased TAG content by 1.81-fold with a significant increase in polyunsaturated fatty acids, particularly EPA and DHA. Moreover, besides increased lipid droplets in the cytosol, ultrastructural observation showed a number of TAG-rich plastoglobuli formed in plastids. CONCLUSION The results suggested that AGPAT1 overexpression could elevate TAG biosynthesis and, moreover, revealed the occurrence of plastidial TAG synthesis in the diatom. Overall, our data provide a new insight into microalgal lipid metabolism and candidate target for metabolic engineering.
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Affiliation(s)
- Srinivasan Balamurugan
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou, 510632 China
| | - Xiang Wang
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou, 510632 China
| | - Hong-Lei Wang
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou, 510632 China
| | - Chun-Jing An
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou, 510632 China
| | - Hui Li
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou, 510632 China
| | - Da-Wei Li
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou, 510632 China
| | - Wei-Dong Yang
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou, 510632 China
| | - Jie-Sheng Liu
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou, 510632 China
| | - Hong-Ye Li
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institute, College of Life Science and Technology, Jinan University, Guangzhou, 510632 China
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Cline SG, Laughbaum IA, Hamel PP. CCS2, an Octatricopeptide-Repeat Protein, Is Required for Plastid Cytochrome c Assembly in the Green Alga Chlamydomonas reinhardtii. FRONTIERS IN PLANT SCIENCE 2017; 8:1306. [PMID: 28824661 PMCID: PMC5541062 DOI: 10.3389/fpls.2017.01306] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Accepted: 07/12/2017] [Indexed: 05/19/2023]
Abstract
In bacteria and energy generating organelles, c-type cytochromes are a class of universal electron carriers with a heme cofactor covalently linked via one or two thioether bonds to a heme binding site. The covalent attachment of heme to apocytochromes is a catalyzed process, taking place via three evolutionarily distinct assembly pathways (Systems I, II, III). System II was discovered in the green alga Chlamydomonas reinhardtii through the genetic analysis of the ccs mutants (cytochrome csynthesis), which display a block in the apo- to holo- form conversion of cytochrome f and c6, the thylakoid lumen resident c-type cytochromes functioning in photosynthesis. Here we show that the gene corresponding to the CCS2 locus encodes a 1,719 amino acid polypeptide and identify the molecular lesions in the ccs2-1 to ccs2-5 alleles. The CCS2 protein displays seven degenerate amino acid repeats, which are variations of the octatricopeptide-repeat motif (OPR) recently recognized in several nuclear-encoded proteins controlling the maturation, stability, or translation of chloroplast transcripts. A plastid site of action for CCS2 is inferred from the finding that GFP fused to the first 100 amino acids of the algal protein localizes to chloroplasts in Nicotiana benthamiana. We discuss the possible functions of CCS2 in the heme attachment reaction.
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Affiliation(s)
- Sara G. Cline
- Department of Molecular Genetics and Department of Biological Chemistry and Pharmacology, The Ohio State University, ColumbusOH, United States
- Plant Cellular and Molecular Biology Graduate Program, The Ohio State University, ColumbusOH, United States
| | - Isaac A. Laughbaum
- Department of Molecular Genetics and Department of Biological Chemistry and Pharmacology, The Ohio State University, ColumbusOH, United States
| | - Patrice P. Hamel
- Department of Molecular Genetics and Department of Biological Chemistry and Pharmacology, The Ohio State University, ColumbusOH, United States
- Plant Cellular and Molecular Biology Graduate Program, The Ohio State University, ColumbusOH, United States
- *Correspondence: Patrice P. Hamel,
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