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Clews AC, Ulch BA, Jesionowska M, Hong J, Mullen RT, Xu Y. Variety of Plant Oils: Species-Specific Lipid Biosynthesis. PLANT & CELL PHYSIOLOGY 2024; 65:845-862. [PMID: 37971406 DOI: 10.1093/pcp/pcad147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/03/2023] [Accepted: 11/15/2023] [Indexed: 11/19/2023]
Abstract
Plant oils represent a large group of neutral lipids with important applications in food, feed and oleochemical industries. Most plants accumulate oils in the form of triacylglycerol within seeds and their surrounding tissues, which comprises three fatty acids attached to a glycerol backbone. Different plant species accumulate unique fatty acids in their oils, serving a range of applications in pharmaceuticals and oleochemicals. To enable the production of these distinctive oils, select plant species have adapted specialized oil metabolism pathways, involving differential gene co-expression networks and structurally divergent enzymes/proteins. Here, we summarize some of the recent advances in our understanding of oil biosynthesis in plants. We compare expression patterns of oil metabolism genes from representative species, including Arabidopsis thaliana, Ricinus communis (castor bean), Linum usitatissimum L. (flax) and Elaeis guineensis (oil palm) to showcase the co-expression networks of relevant genes for acyl metabolism. We also review several divergent enzymes/proteins associated with key catalytic steps of unique oil accumulation, including fatty acid desaturases, diacylglycerol acyltransferases and oleosins, highlighting their structural features and preference toward unique lipid substrates. Lastly, we briefly discuss protein interactomes and substrate channeling for oil biosynthesis and the complex regulation of these processes.
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Affiliation(s)
- Alyssa C Clews
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Brandon A Ulch
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Monika Jesionowska
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Jun Hong
- Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
- Department of Genetics and Developmental Science, Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Robert T Mullen
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Yang Xu
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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2
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Wang K, Zhou Y, Cao L, Lin L, Ledesma-Amaro R, Ji XJ. Engineering Yarrowia lipolytica for Sustainable Production of the Pomegranate Seed Oil-Derived Punicic Acid. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:3088-3098. [PMID: 38282297 DOI: 10.1021/acs.jafc.3c08718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2024]
Abstract
Punicic acid is a conjugated linolenic acid with various biological activities including antiobesity, antioxidant, anticancer, and anti-inflammatory effects. It is often used as a nutraceutical, dietary additive, and animal feed. Currently, punicic acid is primarily extracted from pomegranate seed oil, but it is restricted due to the extended growth cycle, climatic limitations, and low recovery level. There have also been reports on the chemical synthesis of punicic acid, but it resulted in a mixture of structurally similar isomers, requiring additional purification/separation steps. In this study, a comprehensive strategy for the production of punicic acid in Yarrowia lipolytica was implemented by pushing the supply of linoleic acid precursors in a high-oleic oil strain, expressing multiple copies of the fatty acid conjugase gene from Punica granatum, engineering the acyl-editing pathway to improve the phosphatidylcholine pool, and promoting the assembly of punicic acid in the form of triglycerides. The optimal strain with high oil production capacity and a significantly increased punicic acid ratio accumulated 3072.72 mg/L punicic acid, accounting for 6.19% of total fatty acids in fed-batch fermentation, providing a viable, sustainable, and green approach for punicic acid production to substitute plant extraction and chemical synthesis production.
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Affiliation(s)
- Kaifeng Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China
| | - Yueyue Zhou
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China
| | - Lizhen Cao
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China
| | - Lu Lin
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China
| | - Rodrigo Ledesma-Amaro
- Department of Bioengineering and Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, U.K
| | - Xiao-Jun Ji
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, People's Republic of China
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Xu Y, Kambhampati S, Morley SA, Cook R, Froehlich J, Allen DK, Benning C. Arabidopsis ACYL CARRIER PROTEIN4 and RHOMBOID LIKE10 act independently in chloroplast phosphatidate synthesis. PLANT PHYSIOLOGY 2023; 193:2661-2676. [PMID: 37658850 PMCID: PMC10803724 DOI: 10.1093/plphys/kiad483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 08/16/2023] [Accepted: 08/18/2023] [Indexed: 09/05/2023]
Abstract
ACYL CARRIER PROTEIN4 (ACP4) is the most abundant ACP isoform in Arabidopsis (Arabidopsis thaliana) leaves and acts as a scaffold for de novo fatty acid biosynthesis and as a substrate for acyl-ACP-utilizing enzymes. Recently, ACP4 was found to interact with a protein-designated plastid RHOMBOID LIKE10 (RBL10) that affects chloroplast monogalactosyldiacylglycerol (MGDG) biosynthesis, but the cellular function of this interaction remains to be explored. Here, we generated and characterized acp4 rbl10 double mutants to explore whether ACP4 and RBL10 directly interact in influencing chloroplast lipid metabolism. Alterations in the content and molecular species of chloroplast lipids such as MGDG and phosphatidylglycerol were observed in the acp4 and rbl10 mutants, which are likely associated with the changes in the size and profiles of diacylglycerol (DAG), phosphatidic acid (PA), and acyl-ACP precursor pools. ACP4 contributed to the size and profile of the acyl-ACP pool and interacted with acyl-ACP-utilizing enzymes, as expected for its role in fatty acid biosynthesis and chloroplast lipid assembly. RBL10 appeared to be involved in the conversion of PA to DAG precursors for MGDG biosynthesis as evidenced by the increased 34:x PA and decreased 34:x DAG in the rbl10 mutant and the slow turnover of radiolabeled PA in isolated chloroplasts fed with [14C] acetate. Interestingly, the impaired PA turnover in rbl10 was partially reversed in the acp4 rbl10 double mutant. Collectively, this study shows that ACP4 and RBL10 affect chloroplast lipid biosynthesis by modulating substrate precursor pools and appear to act independently.
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Affiliation(s)
- Yang Xu
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
| | | | - Stewart A Morley
- Donald Danforth Plant Science Center, St. Louis, MO 63132, USA
- United States Department of Agriculture, Agriculture Research Service, St. Louis, MO 63132, USA
| | - Ron Cook
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - John Froehlich
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Doug K Allen
- Donald Danforth Plant Science Center, St. Louis, MO 63132, USA
- United States Department of Agriculture, Agriculture Research Service, St. Louis, MO 63132, USA
| | - Christoph Benning
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA
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Xu Y, Singer SD, Chen G. Protein interactomes for plant lipid biosynthesis and their biotechnological applications. PLANT BIOTECHNOLOGY JOURNAL 2023; 21:1734-1744. [PMID: 36762506 PMCID: PMC10440990 DOI: 10.1111/pbi.14027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/18/2023] [Accepted: 02/06/2023] [Indexed: 06/18/2023]
Abstract
Plant lipids have essential biological roles in plant development and stress responses through their functions in cell membrane formation, energy storage and signalling. Vegetable oil, which is composed mainly of the storage lipid triacylglycerol, also has important applications in food, biofuel and oleochemical industries. Lipid biosynthesis occurs in multiple subcellular compartments and involves the coordinated action of various pathways. Although biochemical and molecular biology research over the last few decades has identified many proteins associated with lipid metabolism, our current understanding of the dynamic protein interactomes involved in lipid biosynthesis, modification and channelling is limited. This review examines advances in the identification and characterization of protein interactomes involved in plant lipid biosynthesis, with a focus on protein complexes consisting of different subunits for sequential reactions such as those in fatty acid biosynthesis and modification, as well as transient or dynamic interactomes formed from enzymes in cooperative pathways such as assemblies of membrane-bound enzymes for triacylglycerol biosynthesis. We also showcase a selection of representative protein interactome structures predicted using AlphaFold2, and discuss current and prospective strategies involving the use of interactome knowledge in plant lipid biotechnology. Finally, unresolved questions in this research area and possible approaches to address them are also discussed.
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Affiliation(s)
- Yang Xu
- Department of Molecular and Cellular BiologyUniversity of GuelphGuelphOntarioCanada
| | - Stacy D. Singer
- Agriculture and Agri‐Food Canada, Lethbridge Research and Development CentreLethbridgeAlbertaCanada
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional ScienceUniversity of AlbertaEdmontonAlbertaCanada
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Greenwood BL, Luo Z, Ahmed T, Huang D, Stuart DT. Saccharomyces cerevisiae Δ9-desaturase Ole1 forms a supercomplex with Slc1 and Dga1. J Biol Chem 2023:104882. [PMID: 37269945 PMCID: PMC10302205 DOI: 10.1016/j.jbc.2023.104882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 05/04/2023] [Accepted: 05/07/2023] [Indexed: 06/05/2023] Open
Abstract
Biosynthesis of the various lipid species that compose cellular membranes and lipid droplets depends on the activity of multiple enzymes functioning in coordinated pathways. The flux of intermediates through lipid biosynthetic pathways is regulated to respond to nutritional and environmental demands placed on the cell necessitating that there be extensive flexibility in pathway activity and organization. This flexibility can in part be achieved through the organization of biosynthetic enzymes into metabolon supercomplexes. However, the composition and organization of such supercomplexes remains unclear. Here, we identified protein-protein interactions between acyltransferases Sct1, Gpt2, Slc1, Dga1 and the Δ9 acyl-CoA desaturase Ole1 in Saccharomyces cerevisiae. We further determined that a subset of these acyltransferases interact with each other without Ole1 acting as a scaffold. We show that truncated versions of Dga1 lacking the carboxyl-terminal 20 amino acid residues are non-functional and unable to bind Ole1. Furthermore, charged-to-alanine scanning mutagenesis revealed that a cluster of charged residues near the carboxyl-terminus were required for the interaction with Ole1. Mutation of these charged residues disrupted the interaction between Dga1 and Ole1, but allowed Dga1 to retain catalytic activity and to induce lipid droplet formation. These data support the formation of a complex of acyltransferases involved in lipid biosynthesis that interacts with Ole1, the sole acyl-CoA desaturase in S. cerevisiae, that can channel unsaturated acyl-chains toward phospholipid or triacylglycerol synthesis. This desaturasome complex may provide the architecture that allows for the necessary flux of de novo synthesized unsaturated acyl-CoA to phospholipid or triacylglycerol synthesis as demanded by cellular requirements.
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Affiliation(s)
- Brianna L Greenwood
- Department of Biochemistry, 561 Medical Sciences Building, University of Alberta, Edmonton AB, T6G 2R3, Canada
| | - Zijun Luo
- Department of Biochemistry, 561 Medical Sciences Building, University of Alberta, Edmonton AB, T6G 2R3, Canada
| | - Tareq Ahmed
- Department of Biochemistry, 561 Medical Sciences Building, University of Alberta, Edmonton AB, T6G 2R3, Canada
| | - Daniel Huang
- Department of Biochemistry, 561 Medical Sciences Building, University of Alberta, Edmonton AB, T6G 2R3, Canada
| | - David T Stuart
- Department of Biochemistry, 561 Medical Sciences Building, University of Alberta, Edmonton AB, T6G 2R3, Canada.
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Liu K, Li J, Xing C, Yuan H, Yang J. Characterization of Auxenochlorella protothecoides acyltransferases and potential of their protein interactions to promote the enrichment of oleic acid. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:69. [PMID: 37085915 PMCID: PMC10120206 DOI: 10.1186/s13068-023-02318-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 04/10/2023] [Indexed: 04/23/2023]
Abstract
BACKGROUND After centuries of heavy reliance on fossil fuel energy, the world suffers from an energy crisis and global warming, calling for carbon emission reduction and a transition to clean energy. Microalgae have attracted much attention as a potential feedstock for biofuel production due to their high triacylglycerol content and CO2 sequestration ability. Many diacylglycerol acyltransferases (DGAT) species have been characterized, which catalyze the final committed step in triacylglycerol biosynthesis. However, the detailed structure-function features of DGATs and the role of the interactions among DGAT proteins in lipid metabolism remained largely unknown. RESULTS In this study, the three characterized DGATs of Auxenochlorella protothecoides 2341 showed distinct structural and functional conservation. Functional complementation analyses showed that ApDGAT1 had higher activity than ApDGAT2b in yeast and model microalgae, and ApDGAT2a had no activity in yeast. The N-terminus was not essential to the catalysis function of ApDGAT1 but was crucial to ApDGAT2b as its enzyme activity was sensitive to any N-terminus modifications. Similarly, when acyl-CoA binding proteins (ACBPs) were fused to the N-terminus of ApDGAT1 and ApDGAT2b, zero and significant activity changes were observed, respectively. Interestingly, the ApACBP3 + ApDGAT1 variant contributed to higher oil accumulation than the original DGAT1, and ApACBP1 + ApDGAT1 fusion boosted oleic acid content in yeast. Overexpression of the three DGATs and the variation of ApACBP3 + ApDGAT1 increased the content of C18:1 of Chlamydomonas reinhardtii CC-5235. Significantly, ApDGAT1 interacted with itself, ApDGAT2b, and ApACBP1, which indicated that these three lipid metabolic proteins might have been a part of a dynamic protein interactome that facilitated the enrichment of oleic acid. CONCLUSIONS This study provided new insights into the functional and structural characteristics of DGATs and elucidated the importance of these physical interactions in potential lipid channeling.
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Affiliation(s)
- Kui Liu
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jinyu Li
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Chao Xing
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Hongli Yuan
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jinshui Yang
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
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7
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Cao L, Yin M, Shi TQ, Lin L, Ledesma-Amaro R, Ji XJ. Engineering Yarrowia lipolytica to produce nutritional fatty acids: Current status and future perspectives. Synth Syst Biotechnol 2022; 7:1024-1033. [PMID: 35801090 PMCID: PMC9249680 DOI: 10.1016/j.synbio.2022.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/11/2022] [Accepted: 06/11/2022] [Indexed: 11/26/2022] Open
Abstract
Due to their vital physiological functions, nutritional fatty acids have great potential as nutraceutical food supplements for preventing an array of diseases such as inflammation, depression, arthritis, osteoporosis, diabetes and cancer. Microbial biosynthesis of fatty acids follows the trend of sustainable development, as it enables green, environmentally friendly and efficient production. As a natural oleaginous yeast, Yarrowia lipolytica is especially well-suited for the production of fatty acids. Moreover, it has a variety of genetic engineering tools and novel metabolic engineering strategies that make it a robust workhorse for the production of an array of value-added products. In this review, we summarize recent advances in metabolic engineering strategies for accumulating nutritional fatty acids in Y. lipolytica, including conjugated fatty acids and polyunsaturated fatty acids. In addition, the future prospects of nutritional fatty acid production using the Y. lipolytica platform are discussed in light of the current progress, challenges, and trends in this field. Finally, guidelines for future studies are also emphasized.
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8
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Xu Y. Biochemistry and Biotechnology of Lipid Accumulation in the Microalga Nannochloropsis oceanica. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:11500-11509. [PMID: 36083864 DOI: 10.1021/acs.jafc.2c05309] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Oils are among the most important agricultural commodities and have wide applications in food/nutrition, biofuels, and oleochemicals. The oleaginous microalga Nannochloropsis oceanica can produce large amounts of oils and the high-value ω-3 eicosapentaenoic acid, which represents a promising resource for oil production targeting biodiesel, nutraceutical, and aquaculture industries. In recent years, with the availability of omics databases and the development of genetic tools, N. oceanica has been extensively investigated as a model photosynthetic organism for studying lipid metabolism and as a green cellular factory to produce lipids for industrial applications. This review summarizes the current knowledge on the lipid composition and biosynthetic pathways of N. oceanica and reviews the recent advances in metabolic engineering of lipid production in this microalga.
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Affiliation(s)
- Yang Xu
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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9
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Han L, Silvestre S, Sayanova O, Haslam RP, Napier JA. Using field evaluation and systematic iteration to rationalize the accumulation of omega-3 long-chain polyunsaturated fatty acids in transgenic Camelina sativa. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:1833-1852. [PMID: 35656640 PMCID: PMC9398312 DOI: 10.1111/pbi.13867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
The Brassicaceae Camelina sativa (gold of pleasure) is now an established niche crop and being used as a transgenic host for a range of novel seed traits. Most notable of these is the accumulation of omega-3 long-chain polyunsaturates such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), fatty acids normally only found in marine organisms. As part of continued efforts to optimize the accumulation of these non-native fatty acids via seed-specific expression of algal genes, a new series of iterative constructs was built and introduced into Camelina. Seed fatty acid composition was determined, and the presence of EPA and DHA was confirmed. To provide an additional level of evaluation, full environmental release was carried out on selected events, providing a real-world gauntlet against which to assess the performance of these novel lines. Composition of the seed oil triacylglycerol was determined by mass spectrometry, allowing for conclusions as to the contribution of different activities to the final accumulation of EPA and DHA. Since these data were derived from field-grown material, they also represent a robust demonstration of the stability of the omega-3 LC-PUFA trait in Camelina. We propose that field trialling should be routinely incorporated in the plant synthetic biology 'design-build-test-learn' cycle.
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Affiliation(s)
- Lihua Han
- Plant SciencesRothamsted ResearchHarpenden, HertsUK
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10
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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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11
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Bengtsson JD, Wallis JG, Browse J. Expression of Physaria longchain acyl-CoA synthetases and hydroxy fatty acid accumulation in transgenic Arabidopsis. JOURNAL OF PLANT PHYSIOLOGY 2022; 274:153717. [PMID: 35584570 PMCID: PMC9494924 DOI: 10.1016/j.jplph.2022.153717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/04/2022] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
Hydroxy fatty acids (HFA) are industrially useful chemical feedstocks that accumulate in seed-storage triacylglycerols (TAG) of several plant species, including castor (Ricinus communis) and Physaria (Physaria fendleri). For researchers, HFA also offer a unique opportunity to trace fatty acid metabolism and modification. Past work producing HFA in Arabidopsis (Arabidopsis thaliana) has demonstrated the importance of isozymes of TAG synthesis from plants that evolved to store HFA and as a result have a high degree of specificity towards HFA substrates. Castor phospholipase A2α (RcPLA2) has specificity for HFA-containing phosphatidylcholine. However, expression of RcPLA2 in HFA-accumulating Arabidopsis line CL37-PLA2 reduced HFA content of TAG. This loss was interpreted as being due to poor ability of Arabidopsis longchain acyl-CoA synthetases (LACSs) to utilize HFAs substrates. LACS enzymes are essential to activate HFA to HFA-CoA for TAG synthesis. Physaria is a close relative of Arabidopsis in the Brassicaceae family. To test the hypothesis that this close relatedness would allow Physaria LACSs to interface successfully with Arabidopsis enzymes of seed lipid metabolism and thereby restore HFA accumulation, we transformed PfLACS4 and PfLACS8 constructs into the CL37-PLA2 line. However, HFA content was not recovered, and biochemical characterization of recombinant PfLACS4 and PfLACS8 indicated that these isozymes have substrate specificities and selectivities that are similar to their Arabidopsis orthologues. These and other results pose an important question about how HFA synthesized on phosphatidylcholine can be transferred into the acyl-CoA pool for TAG synthesis.
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Affiliation(s)
- Jesse D Bengtsson
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - James G Wallis
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - John Browse
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA.
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12
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Yang J, Liu J, Pan Y, Maréchal E, Amato A, Liu M, Gong Y, Li Y, Hu H. PDAT regulates PE as transient carbon sink alternative to triacylglycerol in Nannochloropsis. PLANT PHYSIOLOGY 2022; 189:1345-1362. [PMID: 35385114 PMCID: PMC9237688 DOI: 10.1093/plphys/kiac160] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 03/14/2022] [Indexed: 05/21/2023]
Abstract
Triacylglycerols (TAGs) are the main storage lipids in photosynthetic organisms under stress. In the oleaginous alga Nannochloropsis oceanica, while multiple acyl CoA:diacylglycerol (DAG) acyltransferases (NoDGATs) are involved in TAG production, the role of the unique phospholipid:DAG acyltransferase (NoPDAT) remains unknown. Here, we performed a functional complementation assay in TAG-deficient yeast (Saccharomyces cerevisiae) and an in vitro assay to probe the acyltransferase activity of NoPDAT. Subcellular localization, overexpression, and knockdown (KD) experiments were also conducted to elucidate the role of NoPDAT in N. oceanica. NoPDAT, residing at the outermost plastid membrane, does not phylogenetically fall into the clades of algae or plants and uses phosphatidylethanolamine (PE) and phosphatidylglycerol with 16:0, 16:1, and 18:1 at position sn-2 as acyl-donors in vivo. NoPDAT KD, not triggering any compensatory mechanism via DGATs, led to an ∼30% decrease of TAG content, accompanied by a vast accumulation of PEs rich in 16:0, 16:1, and 18:1 fatty acids (referred to as "LU-PE") that was positively associated with CO2 availability. We conclude that the NoPDAT pathway is parallel to and independent of the NoDGAT pathway for oil production. LU-PE can serve as an alternative carbon sink for photosynthetically assimilated carbon in N. oceanica when PDAT-mediated TAG biosynthesis is compromised or under stress in the presence of high CO2 levels.
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Affiliation(s)
| | | | - Yufang Pan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Eric Maréchal
- Laboratoire de Physiologie Cellulaire Végétale, Université Grenoble Alpes, CEA, CNRS, INRA, IRIG‐LPCV, 38054 Grenoble Cedex 9, France
| | - Alberto Amato
- Laboratoire de Physiologie Cellulaire Végétale, Université Grenoble Alpes, CEA, CNRS, INRA, IRIG‐LPCV, 38054 Grenoble Cedex 9, France
| | - Meijing Liu
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Yangmin Gong
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Yantao Li
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science and University of Maryland Baltimore County, Baltimore, Maryland 21202, USA
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13
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Lunn D, Wallis JG, Browse J. A multigene approach secures hydroxy fatty acid production in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2875-2888. [PMID: 35560203 DOI: 10.1093/jxb/erab533] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/02/2021] [Indexed: 06/15/2023]
Abstract
A central goal of green chemistry is to produce industrially useful fatty acids in oilseed crops. Although genes encoding suitable fatty acid-modifying enzymes are available from more than a dozen wild species, progress has been limited because expression of these enzymes in transgenic plants produces only low yields of the desired products. For example, fatty acid hydroxylase 12 (FAH12) from castor (Ricinus communis) produces only 17% hydroxy fatty acids (HFAs) when expressed in Arabidopsis (Arabidopsis thaliana), compared with 90% HFAs in castor seeds. The transgenic plants also have reduced oil content and seed vigor. Here, we review experiments that have provided for steady increased HFA accumulation and oil content. This research has led to exciting new discoveries of enzymes and regulatory processes in the pathways of both seed oil synthesis and lipid metabolism in other parts of the plant. Recent investigations have revealed that HFA-accumulating seeds are unable to rapidly mobilize HFA-containing triacylglycerol (TAG) storage lipid after germination to provide carbon and energy for seedling development, resulting in reduced seedling establishment. These findings present a new opportunity to investigate a different, key area of lipid metabolism-the pathways of TAG lipolysis and β-oxidation in germinating seedlings.
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Affiliation(s)
- Daniel Lunn
- Institute of Biology Chemistry, Washington State University, Pullman, WA 99164-6340, USA
| | - James G Wallis
- Institute of Biology Chemistry, Washington State University, Pullman, WA 99164-6340, USA
| | - John Browse
- Institute of Biology Chemistry, Washington State University, Pullman, WA 99164-6340, USA
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14
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Busta L, Chapman KD, Cahoon EB. Better together: Protein partnerships for lineage-specific oil accumulation. CURRENT OPINION IN PLANT BIOLOGY 2022; 66:102191. [PMID: 35220088 DOI: 10.1016/j.pbi.2022.102191] [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: 12/03/2021] [Revised: 01/18/2022] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
Plant-derived oils are a major agricultural product that exist in both ubiquitous forms such as common vegetable oils and in specialized forms such as castor oil and coconut oil. These specialized oils are the result of lineage-specific metabolic pathways that create oils rich in unusual fatty acids. Considerable progress has been made toward understanding the enzymes that mediate fatty acid biosynthesis, triacylglycerol assembly, and oil storage. However, efforts to translate this knowledge into renewable bioproducts via engineered oil-producing plants and algae have had limited success. Here, we review recent evidence that protein-protein interactions in each of the three major phases of oil formation appear to have profound effects on specialized oil accumulation. We suggest that furthering our knowledge of the noncatalytic attributes of enzymes and other proteins involved in oil formation will be a critical step toward creating renewable bioproducts derived from high performing, engineered oilseeds.
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Affiliation(s)
- Lucas Busta
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, MN, 55812, USA.
| | - Kent D Chapman
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX, 76203, USA
| | - Edgar B Cahoon
- Department of Biochemistry and Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
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15
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Pollard M, Shachar-Hill Y. Kinetic complexities of triacylglycerol accumulation in developing embryos from Camelina sativa provide evidence for multiple biosynthetic systems. J Biol Chem 2022; 298:101396. [PMID: 34774796 PMCID: PMC8715117 DOI: 10.1016/j.jbc.2021.101396] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/28/2021] [Accepted: 11/05/2021] [Indexed: 11/19/2022] Open
Abstract
Quantitative flux maps describing glycerolipid synthesis can be important tools for rational engineering of lipid content and composition in oilseeds. Lipid accumulation in cultured embryos of Camelina sativa is known to mimic that of seeds in terms of rate of lipid synthesis and composition. To assess the kinetic complexity of the glycerolipid flux network, cultured embryos were incubated with [14C/13C]glycerol, and initial and steady state rates of [14C/13Cglyceryl] lipid accumulation were measured. At steady state, the linear accumulations of labeled lipid classes matched those expected from mass compositions. The system showed an apparently simple kinetic precursor-product relationship between the intermediate pool, dominated by diacylglycerol (DAG) and phosphatidylcholine (PC), and the triacylglycerol (TAG) product. We also conducted isotopomer analyses on hydrogenated lipid class species. [13C3glyceryl] labeling of DAG and PC, together with estimates of endogenous [12C3glyceryl] dilution, showed that each biosynthetically active lipid pool is ∼30% of the total by moles. This validates the concept that lipid sub-pools can describe lipid biosynthetic networks. By tracking the kinetics of [13C3glyceryl] and [13C2acyl] labeling, we observed two distinct TAG synthesis components. The major TAG synthesis flux (∼75%) was associated with >95% of the DAG/PC intermediate pool, with little glycerol being metabolized to fatty acids, and with little dilution from endogenous glycerol; a smaller flux exhibited converse characteristics. This kinetic heterogeneity was further explored using postlabeling embryo dissection and differential lipid extractions. The minor flux was tentatively localized to surface cells across the whole embryo. Such heterogeneity must be recognized in order to construct accurate gene expression patterns and metabolic networks describing lipid biosynthesis in developing embryos.
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Affiliation(s)
- Mike Pollard
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
| | - Yair Shachar-Hill
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA.
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16
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Xu Y, Pan X, Lu J, Wang J, Shan Q, Stout J, Chen G. Evolutionary and biochemical characterization of a Chromochloris zofingiensis MBOAT with wax synthase and diacylglycerol acyltransferase activity. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:5584-5598. [PMID: 34037747 DOI: 10.1093/jxb/erab236] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 05/22/2021] [Indexed: 06/12/2023]
Abstract
Wax synthase (WS) catalyzes the last step in wax ester biosynthesis in green plants. Two unrelated sub-families of WS, including the bifunctional acyltransferase and plant-like WS have been reported, but the latter is largely uncharacterized in microalgae. Here, we functionally characterized a putative plant-like WS (CzWS1) from the emerging model green microalga Chromochloris zofingiensis. Our results showed that plant-like WS evolved under different selection constraints in plants and microalgae, with positive selection likely contributing to functional divergence. Unlike jojoba with high amounts of wax ester in seeds and a highly active WS enzyme, C. zofingiensis has no detectable wax ester but a high abundance of WS transcripts. Co-expression analysis showed that C. zofingiensis WS has different expression correlation with lipid biosynthetic genes from jojoba, and may have a divergent function. In vitro characterization indicated that CzWS1 had diacylglycerol acyltransferase activity along with WS activity, and overexpression of CzWS1 in yeast and Chlamydomonas reinhardtii affected triacylglycerol accumulation. Moreover, biochemical and bioinformatic analyses revealed the relevance of the C-terminal region of CzWS1 in enzyme function. Taken together, our results indicated a functional divergence of plant-like WS in plants and microalgae, and the importance of its C-terminal region in specialization of enzyme function.
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Affiliation(s)
- Yang Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Xue Pan
- Center for Plant Cell Biology, Institute of Integrative Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, CA, USA
| | - Junhao Lu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Juli Wang
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Qiyuan Shan
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
- School of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Jake Stout
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
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17
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Xu Y, Caldo KMP, Singer SD, Mietkiewska E, Greer MS, Tian B, Dyer JM, Smith M, Zhou XR, Qiu X, Weselake RJ, Chen G. Physaria fendleri and Ricinus communis lecithin:cholesterol acyltransferase-like phospholipases selectively cleave hydroxy acyl chains from phosphatidylcholine. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 105:182-196. [PMID: 33107656 DOI: 10.1111/tpj.15050] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 10/12/2020] [Accepted: 10/21/2020] [Indexed: 06/11/2023]
Abstract
Production of hydroxy fatty acids (HFAs) in transgenic crops represents a promising strategy to meet our demands for specialized plant oils with industrial applications. The expression of Ricinus communis (castor) OLEATE 12-HYDROXYLASE (RcFAH12) in Arabidopsis has resulted in only limited accumulation of HFAs in seeds, which probably results from inefficient transfer of HFAs from their site of synthesis (phosphatidylcholine; PC) to triacylglycerol (TAG), especially at the sn-1/3 positions of TAG. Phospholipase As (PLAs) may be directly involved in the liberation of HFAs from PC, but the functions of their over-expression in HFA accumulation and distribution at TAG in transgenic plants have not been well studied. In this work, the functions of lecithin:cholesterol acyltransferase-like PLAs (LCAT-PLAs) in HFA biosynthesis were characterized. The LCAT-PLAs were shown to exhibit homology to LCAT and mammalian lysosomal PLA2 , and to contain a conserved and functional Ser/His/Asp catalytic triad. In vitro assays revealed that LCAT-PLAs from the HFA-accumulating plant species Physaria fendleri (PfLCAT-PLA) and castor (RcLCAT-PLA) could cleave acyl chains at both the sn-1 and sn-2 positions of PC, and displayed substrate selectivity towards sn-2-ricinoleoyl-PC over sn-2-oleoyl-PC. Furthermore, co-expression of RcFAH12 with PfLCAT-PLA or RcLCAT-PLA, but not Arabidopsis AtLCAT-PLA, resulted in increased occupation of HFA at the sn-1/3 positions of TAG as well as small but insignificant increases in HFA levels in Arabidopsis seeds compared with RcFAH12 expression alone. Therefore, PfLCAT-PLA and RcLCAT-PLA may contribute to HFA turnover on PC, and represent potential candidates for engineering the production of unusual fatty acids in crops.
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Affiliation(s)
- Yang Xu
- Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Kristian Mark P Caldo
- Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Stacy D Singer
- Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, Alberta, T1J 4B1, Canada
| | - Elzbieta Mietkiewska
- Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Michael S Greer
- Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Bo Tian
- Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
- CAS Key Laboratory of Tropical Plant Resource and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, 650223, China
| | - John M Dyer
- U.S. Department of Agriculture-Agricultural Research Service, US Arid-Land Agricultural Research Center, Maricopa, AZ, 85138, USA
| | - Mark Smith
- Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, Saskatchewan, S7N 0X2, Canada
| | - Xue-Rong Zhou
- CSIRO Agriculture and Food, PO Box 1700, Canberra, ACT, 2601, Australia
| | - Xiao Qiu
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5A8, Canada
| | - Randall J Weselake
- Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
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18
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Regmi A, Shockey J, Kotapati HK, Bates PD. Oil-Producing Metabolons Containing DGAT1 Use Separate Substrate Pools from those Containing DGAT2 or PDAT. PLANT PHYSIOLOGY 2020; 184:720-737. [PMID: 32732347 PMCID: PMC7536707 DOI: 10.1104/pp.20.00461] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 07/23/2020] [Indexed: 05/03/2023]
Abstract
Seed triacylglycerol (TAG) biosynthesis involves a metabolic network containing multiple different diacylglycerol (DAG) and acyl donor substrate pools. This network of pathways overlaps with those for essential membrane lipid synthesis and utilizes multiple different classes of TAG biosynthetic enzymes. Acyl flux through this network ultimately dictates the final oil fatty acid composition. Most strategies to alter seed oil composition involve the overexpression of lipid biosynthetic enzymes, but how these enzymes are assembled into metabolons and which substrate pools are used by each is still not well understood. To understand the roles of different classes of TAG biosynthetic acyltransferases in seed oil biosynthesis, we utilized the Arabidopsis (Arabidopsis thaliana) diacylglycerol acyltransferase mutant dgat1-1 (in which phosphatidylcholine:diacylglycerol acyltransferase (AtPDAT1) is the major TAG biosynthetic enzyme), and enhanced TAG biosynthesis by expression of Arabidopsis acyltransferases AtDGAT1 and AtDGAT2, as well as the DGAT2 enzymes from soybean (Glycine max), and castor (Ricinus communis), followed by isotopic tracing of glycerol flux through the lipid metabolic network in developing seeds. The results indicate each acyltransferase has a unique effect on seed oil composition. AtDGAT1 produces TAG from a rapidly produced phosphatidylcholine-derived DAG pool. However, AtPDAT1 and plant DGAT2 enzymes utilize a different and larger bulk phosphatidylcholine-derived DAG pool that is more slowly turned over for TAG biosynthesis. Based on metabolic fluxes and protein:protein interactions, our model of TAG synthesis suggests that substrate channeling to select enzymes and spatial separation of different acyltransferases into separate metabolons affect efficient TAG production and oil fatty acid composition.
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Affiliation(s)
- Anushobha Regmi
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406
| | - Jay Shockey
- United States Department of Agriculture, Agricultural Research Service, Southern Regional Research Center, New Orleans, Louisiana 70124
| | - Hari Kiran Kotapati
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164
| | - Philip D Bates
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164
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