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Südfeld C, Kiyani A, Wefelmeier K, Wijffels RH, Barbosa MJ, D’Adamo S. Expression of glycerol-3-phosphate acyltransferase increases non-polar lipid accumulation in Nannochloropsis oceanica. Microb Cell Fact 2023; 22:12. [PMID: 36647076 PMCID: PMC9844033 DOI: 10.1186/s12934-022-01987-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 12/09/2022] [Indexed: 01/18/2023] Open
Abstract
Microalgae are considered a suitable production platform for high-value lipids and oleochemicals. Several species including Nannochloropsis oceanica produce large amounts of essential [Formula: see text]-3 polyunsaturated fatty acids (PUFAs) which are integral components of food and feed and have been associated with health-promoting effects. N. oceanica can further accumulate high contents of non-polar lipids with chemical properties that render them a potential replacement for plant oils such as palm oil. However, biomass and lipid productivities obtained with microalgae need to be improved to reach commercial feasibility. Genetic engineering can improve biomass and lipid productivities, for instance by increasing carbon flux to lipids. Here, we report the overexpression of glycerol-3-phosphate acyltransferase (GPAT) in N. oceanica during favorable growth conditions as a strategy to increase non-polar lipid content. Transformants overproducing either an endogenous (NoGPAT) or a heterologous (Acutodesmus obliquus GPAT) GPAT enzyme targeted to the endoplasmic reticulum had up to 42% and 51% increased non-polar lipid contents, respectively, compared to the wild type. Biomass productivities of transformant strains were not substantially impaired, resulting in lipid productivities that were increased by up to 37% and 42% for NoGPAT and AoGPAT transformants, respectively. When exposed to nutrient stress, transformants and wild type had similar lipid contents, suggesting that GPAT enzyme exerts strong flux control on lipid synthesis in N. oceanica under favorable growth conditions. NoGPAT transformants further accumulated PUFAs in non-polar lipids, reaching a total of 6.8% PUFAs per biomass, an increase of 24% relative to the wild type. Overall, our results indicate that GPAT is an interesting target for engineering of lipid metabolism in microalgae, in order to improve non-polar lipid and PUFAs accumulation in microalgae.
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Affiliation(s)
- Christian Südfeld
- grid.4818.50000 0001 0791 5666Wageningen University, Bioprocess Engineering, PO Box 16, 6700 AA Wageningen, Netherlands
| | - Aamna Kiyani
- grid.4818.50000 0001 0791 5666Wageningen University, Bioprocess Engineering, PO Box 16, 6700 AA Wageningen, Netherlands ,grid.412621.20000 0001 2215 1297Department of Microbiology, Quaid-I-Azam University, Islamabad, 45320 Pakistan
| | - Katrin Wefelmeier
- grid.4818.50000 0001 0791 5666Wageningen University, Bioprocess Engineering, PO Box 16, 6700 AA Wageningen, Netherlands
| | - René H. Wijffels
- grid.4818.50000 0001 0791 5666Wageningen University, Bioprocess Engineering, PO Box 16, 6700 AA Wageningen, Netherlands ,grid.465487.cFaculty of Biosciences and Aquaculture, Nord University, N-8049 Bodø, Norway
| | - Maria J. Barbosa
- grid.4818.50000 0001 0791 5666Wageningen University, Bioprocess Engineering, PO Box 16, 6700 AA Wageningen, Netherlands
| | - Sarah D’Adamo
- grid.4818.50000 0001 0791 5666Wageningen University, Bioprocess Engineering, PO Box 16, 6700 AA Wageningen, Netherlands
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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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Ryu AJ, Jeong BR, Kang NK, Jeon S, Sohn MG, Yun HJ, Lim JM, Jeong SW, Park YI, Jeong WJ, Park S, Chang YK, Jeong KJ. Safe-Harboring based novel genetic toolkit for Nannochloropsis salina CCMP1776: Efficient overexpression of transgene via CRISPR/Cas9-Mediated Knock-in at the transcriptional hotspot. BIORESOURCE TECHNOLOGY 2021; 340:125676. [PMID: 34365302 DOI: 10.1016/j.biortech.2021.125676] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 07/23/2021] [Accepted: 07/24/2021] [Indexed: 06/13/2023]
Abstract
Transgene expression in microalgae can be hampered by transgene silencing and unstable expression due to position effects. To overcome this, "safe harboring" transgene expression system was established for Nannochloropsis. Initially, transformants were obtained expressing a sfGFP reporter, followed by screening for high expression of sfGFP with fluorescence-activated cell sorter (FACS). 'T1' transcriptional hotspot was identified from a mutant showing best expression of sfGFP, but did not affect growth or lipid contents. By using a Cas9 editor strain, FAD12 gene, encoding Δ12-fatty acid desaturase (FAD12), was successfully knocked-in at the T1 locus, resulting in significantly higher expression of FAD12 than those of random integration. Importantly, the "safe harbored" FAD12 transformants showed four-fold higher production of linoleic acid (LA), the product of FAD12, leading to 1.5-fold increase in eicosapentaenoic acid (EPA). This safe harboring principle provide excellent proof of the concept for successful genetic/metabolic engineering of microalgae and other organisms.
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Affiliation(s)
- Ae Jin Ryu
- Department of Chemical and Biomolecular Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea; Advanced Biomass R&D Center (ABC), KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Byeong-Ryool Jeong
- Department of Chemical and Biomolecular Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea; School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea; Single-Cell Center, Qingdao Institute of BioEnergy and Bioprocess Technology, Qingdao, Shandong 266101, China
| | - Nam Kyu Kang
- Department of Chemical and Biomolecular Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea; Advanced Biomass R&D Center (ABC), KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea; Carl. R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Seungjib Jeon
- Department of Chemical and Biomolecular Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea; Advanced Biomass R&D Center (ABC), KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Min Gi Sohn
- Department of Chemical and Biomolecular Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Hyo Jin Yun
- Department of Chemical and Biomolecular Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Jong Min Lim
- Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Seok Won Jeong
- Department of Biological Sciences, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Republic of Korea
| | - Youn-Il Park
- Department of Biological Sciences, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Republic of Korea
| | - Won Joong Jeong
- Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Sunghoon Park
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Yong Keun Chang
- Department of Chemical and Biomolecular Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea; Advanced Biomass R&D Center (ABC), KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Ki Jun Jeong
- Department of Chemical and Biomolecular Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea; Institute for the BioCentury, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea.
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4
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Jeon S, Koh HG, Cho JM, Kang NK, Chang YK. Enhancement of lipid production in Nannochloropsis salina by overexpression of endogenous NADP-dependent malic enzyme. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102218] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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5
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Synthetic Biology Approaches To Enhance Microalgal Productivity. Trends Biotechnol 2021; 39:1019-1036. [PMID: 33541719 DOI: 10.1016/j.tibtech.2020.12.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/22/2020] [Accepted: 12/29/2020] [Indexed: 12/15/2022]
Abstract
The major bottleneck in commercializing biofuels and other commodities produced by microalgae is the high cost associated with phototrophic cultivation. Improving microalgal productivities could be a solution to this problem. Synthetic biology methods have recently been used to engineer the downstream production pathways in several microalgal strains. However, engineering upstream photosynthetic and carbon fixation metabolism to enhance growth, productivity, and yield has barely been explored in microalgae. We describe strategies to improve the generation of reducing power from light, as well as to improve the assimilation of CO2 by either the native Calvin cycle or synthetic alternatives. Overall, we are optimistic that recent technological advances will prompt long-awaited breakthroughs in microalgal research.
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Norlina R, Norashikin MN, Loh SH, Aziz A, Cha TS. Exogenous Abscisic Acid Supplementation at Early Stationary Growth Phase Triggers Changes in the Regulation of Fatty Acid Biosynthesis in Chlorella vulgaris UMT-M1. Appl Biochem Biotechnol 2020; 191:1653-1669. [PMID: 32198601 DOI: 10.1007/s12010-020-03312-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 03/12/2020] [Indexed: 11/30/2022]
Abstract
Abscisic acid (ABA) has been known to exist in a microalgal system and serves as one of the chemical stimuli in various biological pathways. Nonetheless, the involvement of ABA in fatty acid biosynthesis, particularly at the transcription level in microalgae is poorly understood. The objective of this study was to determine the effects of exogenous ABA on growth, total oil content, fatty acid composition, and the expression level of beta ketoacyl-ACP synthase I (KAS I) and omega-3 fatty acid desaturase (ω-3 FAD) genes in Chlorella vulgaris UMT-M1. ABA was applied to early stationary C. vulgaris cultures at concentrations of 0, 10, 20, and 80 μM for 48 h. The results showed that ABA significantly increased biomass production and total oil content. The increment of palmitic (C16:0) and stearic (C18:0) acids was coupled by decrement in linoleic (C18:2) and α-linolenic (C18:3n3) acids. Both KAS I and ω-3 FAD gene expression were downregulated, which was negatively correlated to saturated fatty acid (SFAs), but positively correlated to polyunsaturated fatty acid (PUFA) accumulations. Further analysis of both KAS I and ω-3 FAD promoters revealed the presence of multiple ABA-responsive elements (ABREs) in addition to other phytohormone-responsive elements. However, the role of these phytohormone-responsive elements in regulating KAS I and ω-3 FAD gene expression still remains elusive. This revelation might suggest that phytohormone-responsive gene regulation in C. vulgaris and microalgae as a whole might diverge from higher plants which deserve further scientific research to elucidate its functional roles.
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Affiliation(s)
- Ramlee Norlina
- Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, 21030, Kuala Terengganu, Terengganu, Malaysia
| | - Md Nor Norashikin
- Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, 21030, Kuala Terengganu, Terengganu, Malaysia
| | - Saw Hong Loh
- Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, 21030, Kuala Terengganu, Terengganu, Malaysia
| | - Ahmad Aziz
- Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, 21030, Kuala Terengganu, Terengganu, Malaysia
| | - Thye San Cha
- Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, 21030, Kuala Terengganu, Terengganu, Malaysia.
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7
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Abstract
Microalgae are unicellular organisms that act as the crucial primary producers all over the world, typically found in marine and freshwater environments. Most of them can live photo-autotrophically, reproduce rapidly, and accumulate biomass in a short period efficiently. To adapt to the uninterrupted change of the environment, they evolve and differentiate continuously. As a result, some of them evolve special abilities such as toleration of extreme environment, generation of sophisticated structure to adapt to the environment, and avoid predators. Microalgae are believed to be promising bioreactors because of their high lipid and pigment contents. Genetic engineering technologies have given revolutions in the microalgal industry, which decoded the secrets of microalgal genes, express recombinant genes in microalgal genomes, and largely soar the accumulation of interested components in transgenic microalgae. However, owing to several obstructions, the industry of transgenic microalgae is still immature. Here, we provide an overview to emphasize the advantage and imperfection of the existing transgenic microalgal bioreactors.
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Affiliation(s)
- Zhi-Cong Liang
- College of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Ming-Hua Liang
- College of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Jian-Guo Jiang
- College of Food Science and Engineering, South China University of Technology, Guangzhou, China
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8
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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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9
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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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10
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Poliner E, Farré EM, Benning C. Advanced genetic tools enable synthetic biology in the oleaginous microalgae Nannochloropsis sp. PLANT CELL REPORTS 2018; 37:1383-1399. [PMID: 29511798 DOI: 10.1007/s00299-018-2270-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 02/26/2018] [Indexed: 05/16/2023]
Abstract
Nannochloropsis is a genus of fast-growing microalgae that are regularly used for biotechnology applications. Nannochloropsis species have a high triacylglycerol content and their polar lipids are rich in the omega-3 long-chain polyunsaturated fatty acid, eicosapentaenoic acid. Placed in the heterokont lineage, the Nannochloropsis genus has a complex evolutionary history. Genome sequences are available for several species, and a number of transcriptomic datasets have been produced, making this genus a facile model for comparative genomics. There is a growing interest in Nannochloropsis species as models for the study of microalga lipid metabolism and as a chassis for synthetic biology. Recently, techniques for gene stacking, and targeted gene disruption and repression in the Nannochloropsis genus have been developed. These tools enable gene-specific, mechanistic studies and have already allowed the engineering of improved Nannochloropsis strains with superior growth, or greater bioproduction.
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Affiliation(s)
- Eric Poliner
- Cell and Molecular Biology Program, Michigan State University, East Lansing, MI, USA
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
| | - Eva M Farré
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
| | - Christoph Benning
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, USA.
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA.
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA.
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11
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Koh HG, Kang NK, Kim EK, Jeon S, Shin SE, Lee B, Chang YK. Advanced multigene expression system for Nannochloropsis salina using 2A self-cleaving peptides. J Biotechnol 2018; 278:39-47. [PMID: 29715488 DOI: 10.1016/j.jbiotec.2018.04.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 04/25/2018] [Accepted: 04/26/2018] [Indexed: 11/19/2022]
Abstract
Even though there has been much interest in genetic engineering of microalgae, its progress has been slow due to the difficulty and limitation of available techniques. Currently, genetic modification in most microalgal strains is confined to single gene transformation. Here, a multigene expression system for the oleaginous model strain Nannochloropsis salina was developed with glycine-serine-glycine spacer linked 2A self-cleaving peptides (2A) for the first time. An efficiency test of the four most widely used 2As revealed that two different types of 2As T2A and E2A have the best performance in N. salina with a maximum cleavage rate of nearly 45%. The system was able to express the linked sequence of the selection marker shble and the fluorescence protein sfCherry with intact functions. Because 2A enabled multigene expression in the single cassette form, the use of 2A also reduced the vector size, which along with the stronger promoter resulted in a 9-fold increase in the transformation efficiency. Furthermore, confirmative screening accuracy of more than 90% was observed. Hence, the 2A applied vector system is expected to be beneficial in microalgal research field because it enables multigene expression as well as offering improved transformation and screening efficiency.
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Affiliation(s)
- Hyun Gi Koh
- Department of Chemical and Biomolecular Engineering, KAIST, Daejeon 34141, Republic of Korea.
| | - Nam Kyu Kang
- Advanced Biomass R&D Center (ABC), Daejeon 34141, Republic of Korea.
| | - Eun Kyung Kim
- Advanced Biomass R&D Center (ABC), Daejeon 34141, Republic of Korea.
| | - Seungjib Jeon
- Department of Chemical and Biomolecular Engineering, KAIST, Daejeon 34141, Republic of Korea.
| | - Sung-Eun Shin
- Department of Chemical and Biomolecular Engineering, KAIST, Daejeon 34141, Republic of Korea.
| | - Bongsoo Lee
- Department of Chemical and Biomolecular Engineering, KAIST, Daejeon 34141, Republic of Korea.
| | - Yong Keun Chang
- Department of Chemical and Biomolecular Engineering, KAIST, Daejeon 34141, Republic of Korea; Advanced Biomass R&D Center (ABC), Daejeon 34141, Republic of Korea.
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12
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Norashikin MN, Loh SH, Aziz A, Cha TS. Metabolic engineering of fatty acid biosynthesis in Chlorella vulgaris using an endogenous omega-3 fatty acid desaturase gene with its promoter. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.02.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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13
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Effects of disrupted omega-3 desaturase gene construct on fatty acid composition and expression of four fatty acid biosynthetic genes in transgenic Chlorella vulgaris. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.07.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Beacham TA, Sweet JB, Allen MJ. Large scale cultivation of genetically modified microalgae: A new era for environmental risk assessment. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.04.028] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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15
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Fujiwara T, Ohnuma M, Kuroiwa T, Ohbayashi R, Hirooka S, Miyagishima SY. Development of a Double Nuclear Gene-Targeting Method by Two-Step Transformation Based on a Newly Established Chloramphenicol-Selection System in the Red Alga Cyanidioschyzon merolae. FRONTIERS IN PLANT SCIENCE 2017; 8:343. [PMID: 28352279 PMCID: PMC5348525 DOI: 10.3389/fpls.2017.00343] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 02/27/2017] [Indexed: 05/24/2023]
Abstract
The unicellular red alga Cyanidioschyzon merolae possesses a simple cellular architecture that consists of one mitochondrion, one chloroplast, one peroxisome, one Golgi apparatus, and several lysosomes. The nuclear genome content is also simple, with very little genetic redundancy (16.5 Mbp, 4,775 genes). In addition, molecular genetic tools such as gene targeting and inducible gene expression systems have been recently developed. These cytological features and genetic tractability have facilitated various omics analyses. However, only a single transformation selection marker URA has been made available and thus the application of genetic modification has been limited. Here, we report the development of a nuclear targeting method by using chloramphenicol and the chloramphenicol acetyltransferase (CAT) gene. In addition, we found that at least 200-bp homologous arms are required and 500-bp arms are sufficient for a targeted single-copy insertion of the CAT selection marker into the nuclear genome. By means of a combination of the URA and CAT transformation systems, we succeeded in producing a C. merolae strain that expresses HA-cyclin 1 and FLAG-CDKA from the chromosomal CYC1 and CDKA loci, respectively. These methods of multiple nuclear targeting will facilitate genetic manipulation of C. merolae.
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Affiliation(s)
- Takayuki Fujiwara
- Department of Cell Genetics, National Institute of GeneticsShizuoka, Japan
- Japan Science and Technology Agency, Core Research for Evolutional Science and TechnologySaitama, Japan
- Department of Genetics, Graduate University for Advanced StudiesShizuoka, Japan
| | - Mio Ohnuma
- Japan Science and Technology Agency, Core Research for Evolutional Science and TechnologySaitama, Japan
- National Institute of Technology, Hiroshima CollegeHiroshima, Japan
| | - Tsuneyoshi Kuroiwa
- Japan Science and Technology Agency, Core Research for Evolutional Science and TechnologySaitama, Japan
- Department of Chemical and Biological Science, Faculty of Science, Japan Women’s UniversityTokyo, Japan
| | - Ryudo Ohbayashi
- Department of Cell Genetics, National Institute of GeneticsShizuoka, Japan
- Japan Science and Technology Agency, Core Research for Evolutional Science and TechnologySaitama, Japan
| | - Shunsuke Hirooka
- Department of Cell Genetics, National Institute of GeneticsShizuoka, Japan
- Japan Science and Technology Agency, Core Research for Evolutional Science and TechnologySaitama, Japan
| | - Shin-Ya Miyagishima
- Department of Cell Genetics, National Institute of GeneticsShizuoka, Japan
- Japan Science and Technology Agency, Core Research for Evolutional Science and TechnologySaitama, Japan
- Department of Genetics, Graduate University for Advanced StudiesShizuoka, Japan
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16
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Kang NK, Kim EK, Kim YU, Lee B, Jeong WJ, Jeong BR, Chang YK. Increased lipid production by heterologous expression of AtWRI1 transcription factor in Nannochloropsis salina. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:231. [PMID: 29046718 PMCID: PMC5635583 DOI: 10.1186/s13068-017-0919-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 09/30/2017] [Indexed: 05/03/2023]
Abstract
BACKGROUND Genetic engineering of microalgae is necessary to produce economically feasible strains for biofuel production. Current efforts are focused on the manipulation of individual metabolic genes, but the outcomes are not sufficiently stable and/or efficient for large-scale production of biofuels and other materials. Transcription factors (TFs) are emerging as good alternatives for engineering of microalgae, not only to increase production of biomaterials but to enhance stress tolerance. Here, we investigated an AP2 type TF Wrinkled1 in Arabidopsis (AtWRI1) known as a key regulator of lipid biosynthesis in plants, and applied it to industrial microalgae, Nannochloropsis salina. RESULTS We expressed AtWRI1 TF heterologously in N. salina, named NsAtWRI1, in an effort to re-enact its key regulatory function of lipid accumulation. Stable integration AtWRI1 was confirmed by RESDA PCR, and its expression was confirmed by Western blotting using the FLAG tag. Characterizations of transformants revealed that the neutral and total lipid contents were greater in NsAtWRI1 transformants than in WT under both normal and stress conditions from day 8. Especially, total lipid contents were 36.5 and 44.7% higher in NsAtWRI1 2-3 than in WT under normal and osmotic stress condition, respectively. FAME contents of NsAtWRI1 2-3 were also increased compared to WT. As a result, FAME yield of NsAtWRI1 2-3 was increased to 768 mg/L/day, which was 64% higher than that of WT under the normal condition. We identified candidates of AtWRI1-regulated genes by searching for the presence of the AW-box in promoter regions, among which lipid metabolic genes were further analyzed by qRT-PCR. Overall, qRT-PCR results on day 1 indicated that AtWRI1 down-regulated TAGL and DAGK, and up-regulated PPDK, LPL, LPGAT1, and PDH, resulting in enhanced lipid production in NsAtWRI1 transformants from early growth phase. CONCLUSION AtWRI1 TF regulated several genes involved in lipid synthesis in N. salina, resulting in enhancement of neutral lipid and FAME production. These findings suggest that heterologous expression of AtWRI1 TF can be utilized for efficient biofuel production in industrial microalgae.
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Affiliation(s)
- Nam Kyu Kang
- Department of Chemical and Biomolecular Engineering, KAIST, 291, Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - Eun Kyung Kim
- Advanced Biomass R&D Center, 291, Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - Young Uk Kim
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125, Gwahak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - Bongsoo Lee
- Department of Chemical and Biomolecular Engineering, KAIST, 291, Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - Won-Joong Jeong
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125, Gwahak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - Byeong-ryool Jeong
- Department of Chemical and Biomolecular Engineering, KAIST, 291, Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - Yong Keun Chang
- Department of Chemical and Biomolecular Engineering, KAIST, 291, Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
- Advanced Biomass R&D Center, 291, Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
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Heterologous expression of the Streptococcus pneumoniae yoeB and pezT toxin genes is lethal in Chlorella vulgaris. ALGAL RES 2016. [DOI: 10.1016/j.algal.2016.07.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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