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Pan X, Mastrella S, Khamzaaliyeva M, Ashley DD. Exploring the connections between ER-based lipid metabolism and plasma membrane nanodomain signaling. THE NEW PHYTOLOGIST 2024; 243:48-57. [PMID: 38757654 DOI: 10.1111/nph.19815] [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: 03/01/2024] [Accepted: 04/26/2024] [Indexed: 05/18/2024]
Abstract
Recent advancements in our understanding of cell membrane dynamics have shed light on the importance of plasma membrane (PM) nanodomains in plant cell signaling. Nevertheless, many aspects of membrane nanodomains, including their regulatory mechanisms and biological functions, remain enigmatic. To address this knowledge gap, our review article proposes a novel perspective wherein signaling pathways target endoplasmic reticulum (ER)-based lipid metabolism to exert control over the formation and function of membrane nanodomains. Subsequently, these nanodomains reciprocate by influencing the localization and activity of signaling molecules at the PM. We place a specific emphasis on ER-based enzymatic reactions, given the ER's central role in membrane lipid biosynthesis and its capacity to directly impact PM lipid composition, particularly with regard to saturation levels - an essential determinant of nanodomain properties. The interplay among cell signaling, glycerolipid metabolism, and PM nanodomain may create feedforward/feedback loops that fine-tune cellular responses to developmental and environmental cues.
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Affiliation(s)
- Xue Pan
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, M1C 1A4, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Sophia Mastrella
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, M1C 1A4, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Mohinur Khamzaaliyeva
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, M1C 1A4, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Didier-Deschamps Ashley
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, M1C 1A4, Canada
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2
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Claver A, Luján MÁ, Escuín JM, Schilling M, Jouhet J, Savirón M, López MV, Picorel R, Jarne C, Cebolla VL, Alfonso M. Transcriptomic and lipidomic analysis of the differential pathway contribution to the incorporation of erucic acid to triacylglycerol during Pennycress seed maturation. FRONTIERS IN PLANT SCIENCE 2024; 15:1386023. [PMID: 38736440 PMCID: PMC11082276 DOI: 10.3389/fpls.2024.1386023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 04/10/2024] [Indexed: 05/14/2024]
Abstract
Thlaspi arvense (Pennycress) is an emerging feedstock for biofuel production because of its high seed oil content enriched in erucic acid. A transcriptomic and a lipidomic study were performed to analyze the dynamics of gene expression, glycerolipid content and acyl-group distribution during seed maturation. Genes involved in fatty acid biosynthesis were expressed at the early stages of seed maturation. Genes encoding enzymes of the Kennedy pathway like diacylglycerol acyltransferase1 (TaDGAT1), lysophosphatidic acid acyltransferase (TaLPAT) or glycerol 3-phosphate acyltransferase (TaGPAT) increased their expression with maturation, coinciding with the increase in triacylglycerol species containing 22:1. Positional analysis showed that the most abundant triacylglycerol species contained 18:2 at sn-2 position in all maturation stages, suggesting no specificity of the lysophosphatidic acid acyltransferase for very long chain fatty acids. Diacylglycerol acyltransferase2 (TaDGAT2) mRNA was more abundant at the initial maturation stages, coincident with the rapid incorporation of 22:1 to triacylglycerol, suggesting a coordination between Diacylglycerol acyltransferase enzymes for triacylglycerol biosynthesis. Genes encoding the phospholipid-diacylglycerol acyltransferase (TaPDAT1), lysophosphatidylcholine acyltransferase (TaLPCAT) or phosphatidylcholine diacylglycerolcholine phosphotransferase (TaPDCT), involved in acyl-editing or phosphatidyl-choline (PC)-derived diacylglycerol (DAG) biosynthesis showed also higher expression at the early maturation stages, coinciding with a higher proportion of triacylglycerol containing C18 fatty acids. These results suggested a higher contribution of these two pathways at the early stages of seed maturation. Lipidomic analysis of the content and acyl-group distribution of diacylglycerol and phosphatidyl-choline pools was compatible with the acyl content in triacylglycerol at the different maturation stages. Our data point to a model in which a strong temporal coordination between pathways and isoforms in each pathway, both at the expression and acyl-group incorporation, contribute to high erucic triacylglycerol accumulation in Pennycress.
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Affiliation(s)
- Ana Claver
- Department of Plant Biology, Estación Experimental Aula Dei-Consejo Superior de Investigaciones Científicas (EEAD-CSIC), Zaragoza, Spain
| | - María Ángeles Luján
- Department of Plant Biology, Estación Experimental Aula Dei-Consejo Superior de Investigaciones Científicas (EEAD-CSIC), Zaragoza, Spain
| | - José Manuel Escuín
- Instituto de Carboquímica-Consejo Superior de Investigaciones Científicas (ICB-CSIC), Zaragoza, Spain
| | - Marion Schilling
- Laboratoire de Physiologie Cellulaire Végétale, Univ. Grenoble Alpes, Centre National de la Recherche Scientifique-Commisariat de l'Energie Atomique-Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (CNRS-CEA-INRAE), Grenoble, France
| | - Juliette Jouhet
- Laboratoire de Physiologie Cellulaire Végétale, Univ. Grenoble Alpes, Centre National de la Recherche Scientifique-Commisariat de l'Energie Atomique-Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (CNRS-CEA-INRAE), Grenoble, France
| | - María Savirón
- Facultad de Ciencias, Centro de Química y Materiales de Aragón-Consejo Superior de Investigaciones Científicas (CEQMA-CSIC)-Universidad de Zaragoza, Zaragoza, Spain
| | - M. Victoria López
- Department of Soil and Water Conservation, Estación Experimental Aula Dei-Consejo Superior de Investigaciones Científicas (EEAD-CSIC), Zaragoza, Spain
| | - Rafael Picorel
- Department of Plant Biology, Estación Experimental Aula Dei-Consejo Superior de Investigaciones Científicas (EEAD-CSIC), Zaragoza, Spain
| | - Carmen Jarne
- Departamento de Química Analítica, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain
| | - Vicente L. Cebolla
- Instituto de Carboquímica-Consejo Superior de Investigaciones Científicas (ICB-CSIC), Zaragoza, Spain
| | - Miguel Alfonso
- Department of Plant Biology, Estación Experimental Aula Dei-Consejo Superior de Investigaciones Científicas (EEAD-CSIC), Zaragoza, Spain
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3
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Hoffmann DY, Shachar-Hill Y. Do betaine lipids replace phosphatidylcholine as fatty acid editing hubs in microalgae? FRONTIERS IN PLANT SCIENCE 2023; 14:1077347. [PMID: 36743481 PMCID: PMC9892843 DOI: 10.3389/fpls.2023.1077347] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 01/04/2023] [Indexed: 06/18/2023]
Abstract
Acyl editing refers to a deacylation and reacylation cycle on a lipid, which allows for fatty acid desaturation and modification prior to being removed and incorporated into other pools. Acyl editing is an important determinant of glycerolipid synthesis and has been well-characterized in land plants, thus this review begins with an overview of acyl editing in plants. Much less is known about acyl editing in algae, including the extent to which acyl editing impacts lipid synthesis and on which lipid substrate(s) it occurs. This review compares what is known about acyl editing on its major hub phosphatidylcholine (PC) in land plants with the evidence for acyl editing of betaine lipids such as diacylglyceryltrimethylhomoserine (DGTS), the structural analog that replaces PC in several species of microalgae. In land plants, PC is also known to be a major source of fatty acids and diacylglycerol (DAG) for synthesis of the neutral lipid triacylglycerol (TAG). We review the evidence that DGTS contributes substantially to TAG accumulation in algae as a source of fatty acids, but not as a precursor to DAG. We conclude with evidence of acyl editing on other membrane lipid substrates in plants and algae apart from PC or DGTS, and discuss future analyses to elucidate the role of DGTS and other betaine lipids in acyl editing in microalgae.
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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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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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Bhutada G, Menard G, Bhunia RK, Hapeta PP, Ledesma-Amaro R, Eastmond PJ. Production of human milk fat substitute by engineered strains of Yarrowia lipolytica. Metab Eng Commun 2022; 14:e00192. [PMID: 35036316 PMCID: PMC8752951 DOI: 10.1016/j.mec.2022.e00192] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 12/09/2021] [Accepted: 01/03/2022] [Indexed: 01/05/2023] Open
Abstract
Human milk fat has a distinctive stereoisomeric structure where palmitic acid is esterified to the middle (sn-2) position on the glycerol backbone of the triacylglycerol and unsaturated fatty acids to the outer (sn-1/3) positions. This configuration allows for more efficient nutrient absorption in the infant gut. However, the fat used in most infant formulas originates from plants, which exclude palmitic acid from the sn-2 position. Oleaginous yeasts provide an alternative source of lipids for human nutrition. However, these yeasts also exclude palmitic acid from the sn-2 position of their triacylglycerol. Here we show that Yarrowia lipolytica can be engineered to produce triacylglycerol with more than 60% of the palmitic acid in the sn-2 position, by expression of lysophosphatidic acid acyltransferases with palmitoyl-Coenzyme A specificity. The engineered Y. lipolytica strains can be cultured on glycerol, glucose, palm oil or a mixture of substrates, under nitrogen limited condition, to produce triacylglycerol with a fatty acid composition that resembles human milk fat, in terms of the major molecular species (palmitic, oleic and linoleic acids). Culture on palm oil or a mixture of glucose and palm oil produced the highest lipid titre and a triacylglycerol composition that is most similar with human milk fat. Our data show that an oleaginous yeast can be engineered to produce a human milk fat substitute (β-palmitate), that could be used as an ingredient in infant formulas.
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Affiliation(s)
- Govindprasad Bhutada
- Plant Science Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Guillaume Menard
- Plant Science Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Rupam Kumar Bhunia
- Plant Science Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
- Plant Tissue Culture and Genetic Engineering, National Agri-Food Biotechnology Institute, Mohali, Punjab, 140306, India
| | - Piotr P. Hapeta
- Department of Bioengineering and Imperial College Centre for Synthetic Biology, Imperial College London, London, SW72AZ, UK
| | - Rodrigo Ledesma-Amaro
- Department of Bioengineering and Imperial College Centre for Synthetic Biology, Imperial College London, London, SW72AZ, UK
| | - Peter J. Eastmond
- Plant Science Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
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7
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Interactions between plant lipid-binding proteins and their ligands. Prog Lipid Res 2022; 86:101156. [DOI: 10.1016/j.plipres.2022.101156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 10/05/2021] [Accepted: 01/14/2022] [Indexed: 01/11/2023]
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8
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Iwai M, Yamada-Oshima Y, Asami K, Kanamori T, Yuasa H, Shimojima M, Ohta H. Recycling of the major thylakoid lipid MGDG and its role in lipid homeostasis in Chlamydomonas reinhardtii. PLANT PHYSIOLOGY 2021; 187:1341-1356. [PMID: 34618048 PMCID: PMC8566231 DOI: 10.1093/plphys/kiab340] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 06/24/2021] [Indexed: 06/01/2023]
Abstract
Monogalactosyldiacylglycerol (MGDG), the most abundant lipid in thylakoid membranes, is involved in photosynthesis and chloroplast development. MGDG lipase has an important role in lipid remodeling in Chlamydomonas reinhardtii. However, the process related to turnover of the lysogalactolipid that results from MGDG degradation, monogalactosylmonoacylglycerol (MGMG), remains to be clarified. Here we identified a homolog of Arabidopsis thaliana lysophosphatidylcholine acyltransferase (LPCAT) and characterized two independent knockdown (KD) alleles in C. reinhardtii. The enzyme designated as C. reinhardtiiLysolipid Acyltransferase 1 (CrLAT1) has a conserved membrane-bound O-acyl transferase domain. LPCAT from Arabidopsis has a key role in deacylation of phosphatidylcholine (PC). Chlamydomonas reinhardtii, however, lacks PC, and thus we hypothesized that CrLAT1 has some other important function in major lipid flow in this organism. In the CrLAT1 KD mutants, the amount of MGMG was increased, but triacylglycerols (TAGs) were decreased. The proportion of more saturated 18:1 (9) MGDG was lower in the KD mutants than in their parental strain, CC-4533. In contrast, the proportion of MGMG has decreased in the CrLAT1 overexpression (OE) mutants, and the proportion of 18:1 (9) MGDG was higher in the OE mutants than in the empty vector control cells. Thus, CrLAT1 is involved in the recycling of MGDG in the chloroplast and maintains lipid homeostasis in C. reinhardtii.
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Affiliation(s)
- Masako Iwai
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Yui Yamada-Oshima
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Kota Asami
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Takashi Kanamori
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Hideya Yuasa
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Mie Shimojima
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Hiroyuki Ohta
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
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9
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Sarvas C, Puttick D, Forseille L, Cram D, Smith MA. Ectopic expression of cDNAs from larkspur (Consolida ajacis) for increased synthesis of gondoic acid (cis-11 eicosenoic acid) and its positional redistribution in seed triacylglycerol of Camelina sativa. PLANTA 2021; 254:32. [PMID: 34287699 DOI: 10.1007/s00425-021-03682-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 07/10/2021] [Indexed: 06/13/2023]
Abstract
A β-ketoacyl-ACP-synthase II (KAS2) like enzyme and a lysophosphatidic acid acyltransferase (LPAT2) from Consolida ajacis catalyze gondoic acid biosynthesis and incorporation into the sn-2 position of seed TAG in engineered Camelina sativa. Gondoic acid (cis-11 eicosenoic acid, 20:1∆11) is the predominant very-long-chain fatty acid (VLCFA) in camelina (Camelina sativa) seed oil accounting for 12-15% of total triacylglycerol fatty acids. To explore the feasibility of engineering increased levels of this fatty acid in camelina seed, oils from a range of plant species were analyzed to identify those producing 20-Carbon (C20) fatty acids as the only VLCFAs in their seed oil. Seeds of Consolida and Delphinium species (Ranunculaceae) were found to contain moderate levels (0.2% to 25.5%) of C20 fatty acids without accompanying longer chain fatty acids. The C20 fatty acids were abundant in both sn-2 and sn-1/3 positions of seed TAG in Consolida, but were largely absent from the sn-2 position in Delphinium seed TAG. Through generation of a developing seed transcriptome, sequences were identified and cDNAs amplified from Consolida ajacis encoding a β-ketoacyl-ACP-synthase II like protein (CaKAS2B) that lacked a predicted chloroplast transit peptide, and two homologues of Arabidopsis thaliana lysophosphatidic acid acyltransferase 2 (CaLPAT2a and CaLPAT2b). Expression of CaKAS2B in conventional (WT) camelina and a line previously engineered for high seed oleic acid content (HO) resulted in increased seed VLCFA content. Total VLCFA levels were raised from 24 to 35% and from 7 to 23% in T3 seed from representative transformants in the WT and HO backgrounds, respectively. Gondoic acid was the predominant VLCFA in transformed HO lines with low endogenous cytoplasmic fatty acid elongation activity, suggesting limited capacity of CaKAS2B to elongate beyond C20. Expression in camelina of CaLPAT2b resulted in significantly increased C20-VLCFA esterification at the sn-2 position of seed TAG with VLCFA levels of 33.8% in this position in one transformed line compared to 0.3% at sn-2 in the corresponding control line. Only small changes in total seed VLCFA content were observed in transformed lines implying that increased VLCFA esterification capacity in camelina results in positional redistribution of VLCFAs but does not significantly enhance flux through the fatty acid elongation pathway. The full potential of CaKAS2B and CaLPAT2a for the engineering of high gondoic acid levels in camelina remains to be determined. Seed fatty acid composition of Consolida and Delphinium also provides information that may be of value in the systematics of the Ranunculaceae.
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Affiliation(s)
- Carlene Sarvas
- Linnaeus Plant Sciences, 2024-110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Debbie Puttick
- Linnaeus Plant Sciences, 2024-110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Li Forseille
- National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Dustin Cram
- National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Mark A Smith
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, SK, S7N 0X2, Canada.
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10
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Gopalam R, Datey A, Bijoor S, Chakravortty D, Tumaney AW. Biochemical Characterization of Acyl-CoA: Lysophosphatidylcholine Acyltransferase (LPCAT) Enzyme from the Seeds of Salvia hispanica. Mol Biotechnol 2021; 63:963-972. [PMID: 34129179 DOI: 10.1007/s12033-021-00354-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 06/08/2021] [Indexed: 11/26/2022]
Abstract
Salvia hispanica (chia) is the highest reported terrestrial plant source of alpha-linolenic acid (ALA, ~ 65%), an ω-3 polyunsaturated fatty acid with numerous health benefits. The molecular basis of high ALA accumulation in chia is yet to be understood. We have identified lysophosphatidylcholine acyltransferase (LPCAT) gene from the developing seed transcriptome data of chia and carried out its biochemical characterization through heterologous expression in Saccharomyces cerevisiae. Expression profiling showed that the enzyme was active throughout the seed development, indicating a pivotal role in oil biosynthesis. The enzyme could utilize both saturated and unsaturated lysophosphatidylcholine substrates at the same rate, to synthesize phosphatidylcholine (PC). The enzyme also exhibited lysophosphatidic acid acyltransferase (LPAAT) activity, by preferring lysophosphatidic acid substrate. Substrate specificity studies showed that the enzyme preferred both monounsaturated and polyunsaturated fatty acyl CoAs over saturated CoAs. This activity may play a key role in enriching the PC fraction with polyunsaturated fatty acids (PUFAs). PUFAs present on PC can be transferred to oil through the action of other acyltransferases. Our results describe a new LPCAT enzyme that can be used to biotechnologically alter oilseed crops to incorporate more PUFA in its seed oil.
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Affiliation(s)
- Rahul Gopalam
- Department of Lipid Science, CSIR-Central Food Technological Research Institute (CSIR-CFTRI), Mysore, 570020, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Akshay Datey
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, 560012, India
| | - Sharath Bijoor
- Department of Lipid Science, CSIR-Central Food Technological Research Institute (CSIR-CFTRI), Mysore, 570020, India
| | - Dipshikha Chakravortty
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, 560012, India
| | - Ajay W Tumaney
- Department of Lipid Science, CSIR-Central Food Technological Research Institute (CSIR-CFTRI), Mysore, 570020, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
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11
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Production of the infant formula ingredient 1,3-olein-2-palmitin in Arabidopsis thaliana seeds. Metab Eng 2021; 67:67-74. [PMID: 34091040 DOI: 10.1016/j.ymben.2021.05.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 05/07/2021] [Accepted: 05/29/2021] [Indexed: 11/24/2022]
Abstract
In human milk fat, palmitic acid (16:0) is esterified to the middle (sn-2 or β) position on the glycerol backbone and oleic acid (18:1) predominantly to the outer positions, giving the triacylglycerol (TG) a distinctive stereoisomeric structure that is believed to assist nutrient absorption in the infant gut. However, the fat used in most infant formulas is derived from plants, which preferentially esterify 16:0 to the outer positions. We have previously showed that the metabolism of the model oilseed Arabidopsis thaliana can be engineered to incorporate 16:0 into the middle position of TG. However, the fatty acyl composition of Arabidopsis seed TG does not mimic human milk, which is rich in both 16:0 and 18:1 and is defined by the high abundance of the TG molecular species 1,3-olein-2-palmitin (OPO). Here we have constructed an Arabidopsis fatty acid biosynthesis 1-1 fatty acid desaturase 2 fatty acid elongase 1 mutant with around 20% 16:0 and 70% 18:1 in its seeds and we have engineered it to esterify more than 80% of the 16:0 to the middle position of TG, using heterologous expression of the human lysophosphatidic acid acyltransferase isoform AGPAT1, combined with suppression of LYSOPHOSPHATIDIC ACID ACYLTRANSFERASE 2 and PHOSPHATIDYLCHOLINE:DIACYLGLYCEROL CHOLINEPHOSPHOTRANSFERASE. Our data show that oilseeds can be engineered to produce TG that is rich in OPO, which is a structured fat ingredient used in infant formulas.
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12
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Young DY, Shachar-Hill Y. Large fluxes of fatty acids from membranes to triacylglycerol and back during N-deprivation and recovery in Chlamydomonas. PLANT PHYSIOLOGY 2021; 185:796-814. [PMID: 33822218 PMCID: PMC8133548 DOI: 10.1093/plphys/kiaa071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/23/2020] [Indexed: 06/12/2023]
Abstract
Microalgae accumulate triacylglycerol (TAG) during nutrient deprivation and break it down after nutrient resupply, and these processes involve dramatic shifts in cellular carbon allocation. Due to the importance of algae in the global carbon cycle, and the potential of algal lipids as feedstock for chemical and fuel production, these processes are of both ecophysiological and biotechnological importance. However, the metabolism of TAG is not well understood, particularly the contributions of fatty acids (FAs) from different membrane lipids to TAG accumulation and the fate of TAG FAs during degradation. Here, we used isotopic labeling time course experiments on Chlamydomonas reinhardtii to track FA synthesis and transfer between lipid pools during nitrogen (N)-deprivation and resupply. When cells were labeled before N-deprivation, total levels of label in cellular FAs were unchanged during subsequent N-deprivation and later resupply, despite large fluxes into and out of TAG and membrane lipid pools. Detailed analyses of FA levels and labeling revealed that about one-third of acyl chains accumulating in TAG during N-deprivation derive from preexisting membrane lipids, and in total, at least 45% of TAG FAs passed through membrane lipids at one point. Notably, most acyl chains in membrane lipids during recovery after N-resupply come from TAG. Fluxes of polyunsaturated FAs from plastidic membranes into TAG during N-deprivation were particularly noteworthy. These findings demonstrate a high degree of integration of TAG and membrane lipid metabolism and highlight a role for TAG in storage and supply of membrane lipid components.
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Affiliation(s)
- Danielle Yvonne Young
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, 48824, USA
| | - Yair Shachar-Hill
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, 48824, USA
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13
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Kawiński A, Miklaszewska M, Stelter S, Głąb B, Banaś A. Lipases of germinating jojoba seeds efficiently hydrolyze triacylglycerols and wax esters and display wax ester-synthesizing activity. BMC PLANT BIOLOGY 2021; 21:50. [PMID: 33468064 PMCID: PMC7814598 DOI: 10.1186/s12870-020-02823-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 12/30/2020] [Indexed: 05/24/2023]
Abstract
BACKGROUND Simmondsia chinensis (jojoba) is the only plant known to store wax esters instead of triacylglycerols in its seeds. Wax esters are composed of very-long-chain monounsaturated fatty acids and fatty alcohols and constitute up to 60% of the jojoba seed weight. During jojoba germination, the first step of wax ester mobilization is catalyzed by lipases. To date, none of the jojoba lipase-encoding genes have been cloned and characterized. In this study, we monitored mobilization of storage reserves during germination of jojoba seeds and performed detailed characterization of the jojoba lipases using microsomal fractions isolated from germinating seeds. RESULTS During 26 days of germination, we observed a 60-70% decrease in wax ester content in the seeds, which was accompanied by the reduction of oleosin amounts and increase in glucose content. The activity of jojoba lipases in the seed microsomal fractions increased in the first 50 days of germination. The enzymes showed higher activity towards triacylglycerols than towards wax esters. The maximum lipase activity was observed at 60 °C and pH around 7 for triacylglycerols and 6.5-8 for wax esters. The enzyme efficiently hydrolyzed various wax esters containing saturated and unsaturated acyl and alcohol moieties. We also demonstrated that jojoba lipases possess wax ester-synthesizing activity when free fatty alcohols and different acyl donors, including triacylglycerols and free fatty acids, are used as substrates. For esterification reactions, the enzyme utilized both saturated and unsaturated fatty alcohols, with the preference towards long chain and very long chain compounds. CONCLUSIONS In in vitro assays, jojoba lipases catalyzed hydrolysis of triacylglycerols and different wax esters in a broad range of temperatures. In addition, the enzymes had the ability to synthesize wax esters in the backward reaction. Our data suggest that jojoba lipases may be more similar to other plant lipases than previously assumed.
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Affiliation(s)
- Adam Kawiński
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307, Gdańsk, Poland
| | - Magdalena Miklaszewska
- Department of Plant Physiology and Biotechnology, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland.
| | - Szymon Stelter
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307, Gdańsk, Poland
| | - Bartosz Głąb
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307, Gdańsk, Poland
| | - Antoni Banaś
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307, Gdańsk, Poland
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14
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Correa SM, Alseekh S, Atehortúa L, Brotman Y, Ríos-Estepa R, Fernie AR, Nikoloski Z. Model-assisted identification of metabolic engineering strategies for Jatropha curcas lipid pathways. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 104:76-95. [PMID: 33001507 DOI: 10.1111/tpj.14906] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 06/03/2020] [Accepted: 06/12/2020] [Indexed: 06/11/2023]
Abstract
Efficient approaches to increase plant lipid production are necessary to meet current industrial demands for this important resource. While Jatropha curcas cell culture can be used for in vitro lipid production, scaling up the system for industrial applications requires an understanding of how growth conditions affect lipid metabolism and yield. Here we present a bottom-up metabolic reconstruction of J. curcas supported with labeling experiments and biomass characterization under three growth conditions. We show that the metabolic model can accurately predict growth and distribution of fluxes in cell cultures and use these findings to pinpoint energy expenditures that affect lipid biosynthesis and metabolism. In addition, by using constraint-based modeling approaches we identify network reactions whose joint manipulation optimizes lipid production. The proposed model and computational analyses provide a stepping stone for future rational optimization of other agronomically relevant traits in J. curcas.
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Affiliation(s)
- Sandra M Correa
- Genetics of Metabolic Traits Group, Max Planck Institute of Molecular Plant Physiology, Potsdam, 14476, Germany
- Grupo de Biotecnología, Departamento de Ciencias Exactas y Naturales, Universidad de Antioquia, Medellín, 050010, Colombia
| | - Saleh Alseekh
- Central Metabolism Group, Max Planck Institute of Molecular Plant Physiology, Potsdam, 14476, Germany
- Centre for Plant Systems Biology and Biotechnology, Plovdiv, 4000, Bulgaria
| | - Lucía Atehortúa
- Grupo de Biotecnología, Departamento de Ciencias Exactas y Naturales, Universidad de Antioquia, Medellín, 050010, Colombia
| | - Yariv Brotman
- Genetics of Metabolic Traits Group, Max Planck Institute of Molecular Plant Physiology, Potsdam, 14476, Germany
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, 8410501, Israel
| | - Rigoberto Ríos-Estepa
- Grupo de Bioprocesos, Departamento de Ingeniería Química, Universidad de Antioquia, Medellín, 050010, Colombia
| | - Alisdair R Fernie
- Central Metabolism Group, Max Planck Institute of Molecular Plant Physiology, Potsdam, 14476, Germany
- Centre for Plant Systems Biology and Biotechnology, Plovdiv, 4000, Bulgaria
| | - Zoran Nikoloski
- Centre for Plant Systems Biology and Biotechnology, Plovdiv, 4000, Bulgaria
- Bioinformatics, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, 14476, Germany
- Systems Biology and Mathematical Modelling Group, Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
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15
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Xu Y, Mietkiewska E, Shah S, Weselake RJ, Chen G. Punicic acid production in Brassica napus. Metab Eng 2020; 62:20-29. [PMID: 32841680 DOI: 10.1016/j.ymben.2020.08.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/03/2020] [Accepted: 08/20/2020] [Indexed: 11/17/2022]
Abstract
Punicic acid (PuA; 18:3Δ9cis,11trans,13cis), a conjugated linolenic acid isomer bearing three conjugated double bonds, is associated with various health benefits and has potential for industrial use. The major nature source of this unusual fatty acid is pomegranate (Punica granatum) seed oil, which contains up to 80% (w/w) of its fatty acids as PuA. Pomegranate seed oil, however, is low yielding with unstable production and thus limits the supply of PuA. Metabolic engineering of established temperate oil crops for PuA production, therefore, has the potential to be a feasible strategy to overcome the limitations associated with sourcing PuA from pomegranate. In this study, the cDNAs encoding a pomegranate fatty acid conjugase and a pomegranate oleate desaturase were co-expressed in canola-type Brassica napus. Transgenic B. napus lines accumulated up to 11% (w/w) of the total fatty acids as PuA in the seed oil, which is the highest level of PuA reported in metabolically engineered oilseed crops so far. Levels of seed oil PuA were stable over two generations and had no negative effects on seed germination. The transgenic B. napus lines with the highest PuA levels contained multiple transgene insertions and the PuA content of B. napus seed oil was correlated with efficiency of oleic acid desaturation and linoleic acid conjugation. In addition, PuA accumulated at lower levels in polar lipids (5.0-6.9%) than triacylglycerol (7.5-10.6%), and more than 60% of triacylglycerol-associated PuA was present at the sn-2 position. This study provides the basis for the commercial production of PuA in transgenic oilseed crops and thus would open new prospects for the application of this unusual fatty acid in health and industry.
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Affiliation(s)
- Yang Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Elzbieta Mietkiewska
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Saleh Shah
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Randall J Weselake
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada.
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16
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Correa SM, Fernie AR, Nikoloski Z, Brotman Y. Towards model-driven characterization and manipulation of plant lipid metabolism. Prog Lipid Res 2020; 80:101051. [PMID: 32640289 DOI: 10.1016/j.plipres.2020.101051] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 06/20/2020] [Accepted: 06/21/2020] [Indexed: 01/09/2023]
Abstract
Plant lipids have versatile applications and provide essential fatty acids in human diet. Therefore, there has been a growing interest to better characterize the genetic basis, regulatory networks, and metabolic pathways that shape lipid quantity and composition. Addressing these issues is challenging due to context-specificity of lipid metabolism integrating environmental, developmental, and tissue-specific cues. Here we systematically review the known metabolic pathways and regulatory interactions that modulate the levels of storage lipids in oilseeds. We argue that the current understanding of lipid metabolism provides the basis for its study in the context of genome-wide plant metabolic networks with the help of approaches from constraint-based modeling and metabolic flux analysis. The focus is on providing a comprehensive summary of the state-of-the-art of modeling plant lipid metabolic pathways, which we then contrast with the existing modeling efforts in yeast and microalgae. We then point out the gaps in knowledge of lipid metabolism, and enumerate the recent advances of using genome-wide association and quantitative trait loci mapping studies to unravel the genetic regulations of lipid metabolism. Finally, we offer a perspective on how advances in the constraint-based modeling framework can propel further characterization of plant lipid metabolism and its rational manipulation.
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Affiliation(s)
- Sandra M Correa
- Genetics of Metabolic Traits Group, Max Planck Institute for Molecular Plant Physiology, Potsdam 14476, Germany; Department of Life Sciences, Ben-Gurion University of the Negev, 8410501 Beer-Sheva, Israel; Departamento de Ciencias Exactas y Naturales, Universidad de Antioquia, Medellín 050010, Colombia.
| | - Alisdair R Fernie
- Central Metabolism Group, Max Planck Institute for Molecular Plant Physiology, Potsdam 14476, Germany; Center of Plant Systems Biology and Biotechnology, Plovdiv, Bulgaria
| | - Zoran Nikoloski
- Center of Plant Systems Biology and Biotechnology, Plovdiv, Bulgaria; Bioinformatics, Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam, Germany; Systems Biology and Mathematical Modelling Group, Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm 14476, Germany.
| | - Yariv Brotman
- Genetics of Metabolic Traits Group, Max Planck Institute for Molecular Plant Physiology, Potsdam 14476, Germany; Department of Life Sciences, Ben-Gurion University of the Negev, 8410501 Beer-Sheva, Israel
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17
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Shiva S, Samarakoon T, Lowe KA, Roach C, Vu HS, Colter M, Porras H, Hwang C, Roth MR, Tamura P, Li M, Schrick K, Shah J, Wang X, Wang H, Welti R. Leaf Lipid Alterations in Response to Heat Stress of Arabidopsis thaliana. PLANTS 2020; 9:plants9070845. [PMID: 32635518 PMCID: PMC7412450 DOI: 10.3390/plants9070845] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 06/30/2020] [Accepted: 07/03/2020] [Indexed: 01/19/2023]
Abstract
In response to elevated temperatures, plants alter the activities of enzymes that affect lipid composition. While it has long been known that plant leaf membrane lipids become less unsaturated in response to heat, other changes, including polygalactosylation of galactolipids, head group acylation of galactolipids, increases in phosphatidic acid and triacylglycerols, and formation of sterol glucosides and acyl sterol glucosides, have been observed more recently. In this work, by measuring lipid levels with mass spectrometry, we confirm the previously observed changes in Arabidopsis thaliana leaf lipids under three heat stress regimens. Additionally, in response to heat, increased oxidation of the fatty acyl chains of leaf galactolipids, sulfoquinovosyldiacylglycerols, and phosphatidylglycerols, and incorporation of oxidized acyl chains into acylated monogalactosyldiacylglycerols are shown. We also observed increased levels of digalactosylmonoacylglycerols and monogalactosylmonoacylglycerols. The hypothesis that a defect in sterol glycosylation would adversely affect regrowth of plants after a severe heat stress regimen was tested, but differences between wild-type and sterol glycosylation-defective plants were not detected.
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Affiliation(s)
- Sunitha Shiva
- Division of Biology, Kansas State University, Ackert Hall, Manhattan, KS 66506-4901, USA; (T.S.); (K.A.L.); (C.R.); (H.S.V.); (M.C.); (H.P.); (C.H.); (M.R.R.); (P.T.); (K.S.)
- Correspondence: (S.S.); (R.W.)
| | - Thilani Samarakoon
- Division of Biology, Kansas State University, Ackert Hall, Manhattan, KS 66506-4901, USA; (T.S.); (K.A.L.); (C.R.); (H.S.V.); (M.C.); (H.P.); (C.H.); (M.R.R.); (P.T.); (K.S.)
| | - Kaleb A. Lowe
- Division of Biology, Kansas State University, Ackert Hall, Manhattan, KS 66506-4901, USA; (T.S.); (K.A.L.); (C.R.); (H.S.V.); (M.C.); (H.P.); (C.H.); (M.R.R.); (P.T.); (K.S.)
| | - Charles Roach
- Division of Biology, Kansas State University, Ackert Hall, Manhattan, KS 66506-4901, USA; (T.S.); (K.A.L.); (C.R.); (H.S.V.); (M.C.); (H.P.); (C.H.); (M.R.R.); (P.T.); (K.S.)
| | - Hieu Sy Vu
- Division of Biology, Kansas State University, Ackert Hall, Manhattan, KS 66506-4901, USA; (T.S.); (K.A.L.); (C.R.); (H.S.V.); (M.C.); (H.P.); (C.H.); (M.R.R.); (P.T.); (K.S.)
| | - Madeline Colter
- Division of Biology, Kansas State University, Ackert Hall, Manhattan, KS 66506-4901, USA; (T.S.); (K.A.L.); (C.R.); (H.S.V.); (M.C.); (H.P.); (C.H.); (M.R.R.); (P.T.); (K.S.)
| | - Hollie Porras
- Division of Biology, Kansas State University, Ackert Hall, Manhattan, KS 66506-4901, USA; (T.S.); (K.A.L.); (C.R.); (H.S.V.); (M.C.); (H.P.); (C.H.); (M.R.R.); (P.T.); (K.S.)
| | - Caroline Hwang
- Division of Biology, Kansas State University, Ackert Hall, Manhattan, KS 66506-4901, USA; (T.S.); (K.A.L.); (C.R.); (H.S.V.); (M.C.); (H.P.); (C.H.); (M.R.R.); (P.T.); (K.S.)
| | - Mary R. Roth
- Division of Biology, Kansas State University, Ackert Hall, Manhattan, KS 66506-4901, USA; (T.S.); (K.A.L.); (C.R.); (H.S.V.); (M.C.); (H.P.); (C.H.); (M.R.R.); (P.T.); (K.S.)
| | - Pamela Tamura
- Division of Biology, Kansas State University, Ackert Hall, Manhattan, KS 66506-4901, USA; (T.S.); (K.A.L.); (C.R.); (H.S.V.); (M.C.); (H.P.); (C.H.); (M.R.R.); (P.T.); (K.S.)
| | - Maoyin Li
- Department of Biological Sciences, University of North Texas, Denton, TX 76203-5017, USA; (M.L.); (X.W.)
- Department of Biology, University of Missouri-St. Louis, St. Louis, MO 63121-4499, USA
| | - Kathrin Schrick
- Division of Biology, Kansas State University, Ackert Hall, Manhattan, KS 66506-4901, USA; (T.S.); (K.A.L.); (C.R.); (H.S.V.); (M.C.); (H.P.); (C.H.); (M.R.R.); (P.T.); (K.S.)
| | - Jyoti Shah
- Donald Danforth Plant Science Center, St. Louis, MO 63132, USA;
| | - Xuemin Wang
- Department of Biological Sciences, University of North Texas, Denton, TX 76203-5017, USA; (M.L.); (X.W.)
- Department of Biology, University of Missouri-St. Louis, St. Louis, MO 63121-4499, USA
| | - Haiyan Wang
- Department of Statistics, Kansas State University, Manhattan, KS 66506-0802, USA;
| | - Ruth Welti
- Division of Biology, Kansas State University, Ackert Hall, Manhattan, KS 66506-4901, USA; (T.S.); (K.A.L.); (C.R.); (H.S.V.); (M.C.); (H.P.); (C.H.); (M.R.R.); (P.T.); (K.S.)
- Correspondence: (S.S.); (R.W.)
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18
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Bai S, Wallis JG, Denolf P, Engelen S, Bengtsson JD, Van Thournout M, Dierickx J, Haesendonckx B, Browse J. The biochemistry of headgroup exchange during triacylglycerol synthesis in canola. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:83-94. [PMID: 31991038 PMCID: PMC7605783 DOI: 10.1111/tpj.14709] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 12/18/2019] [Accepted: 01/07/2020] [Indexed: 05/05/2023]
Abstract
Many pathways of primary metabolism are substantially conserved within and across plant families. However, significant differences in organization and fluxes through a reaction network may occur, even between plants in closely related genera. Assessing and understanding these differences is key to appreciating metabolic diversity, and to attempts to engineer plant metabolism for higher crop yields and desired product profiles. To better understand lipid metabolism and seed oil synthesis in canola (Brassica napus), we have characterized four canola homologues of the Arabidopsis (Arabidopsis thaliana) ROD1 gene. AtROD1 encodes phosphatidylcholine:diacylglycerol cholinephosphotransferase (PDCT), the enzyme that catalyzes a major flux of polyunsaturated fatty acids (PUFAs) in oil synthesis. Assays in yeast indicated that only two of the canola genes, BnROD1.A3 and BnROD1.C3, encode active isozymes of PDCT, and these genes are strongly expressed during the period of seed oil synthesis. Loss of expression of BnROD1.A3 and BnROD1.C3 in a double mutant, or by RNA interference, reduced the PUFA content of the oil to 26.6% compared with 32.5% in the wild type. These results indicate that ROD1 isozymes in canola are responsible for less than 20% of the PUFAs that accumulate in the seed oil compared with 40% in Arabidopsis. Our results demonstrate the care needed when translating results from a model species to crop plants.
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Affiliation(s)
- Shuangyi Bai
- Institute of Biological Chemistry, Washington State University, PO Box 646340, Pullman, WA 99164-6340, USA
| | - James G. Wallis
- Institute of Biological Chemistry, Washington State University, PO Box 646340, Pullman, WA 99164-6340, USA
| | - Peter Denolf
- BASF Innovation Center Gent, NV Technologiepark 101, B-9052, Ghent, Belgium
| | - Steven Engelen
- BASF Innovation Center Gent, NV Technologiepark 101, B-9052, Ghent, Belgium
| | - Jesse D. Bengtsson
- Institute of Biological Chemistry, Washington State University, PO Box 646340, Pullman, WA 99164-6340, USA
| | | | - Jo Dierickx
- BASF Innovation Center Gent, NV Technologiepark 101, B-9052, Ghent, Belgium
| | - Boris Haesendonckx
- BASF Innovation Center Gent, NV Technologiepark 101, B-9052, Ghent, Belgium
| | - John Browse
- Institute of Biological Chemistry, Washington State University, PO Box 646340, Pullman, WA 99164-6340, USA
- For correspondence ()
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19
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Sun Y, Yao R, Ji X, Wu H, Luna A, Wang Z, Jetter R. Characterization of an alkylresorcinol synthase that forms phenolics accumulating in the cuticular wax on various organs of rye (Secale cereale). THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:1294-1312. [PMID: 31981252 DOI: 10.1111/tpj.14704] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/18/2019] [Accepted: 01/07/2020] [Indexed: 06/10/2023]
Abstract
Alkylresorcinols are bioactive compounds produced in diverse plant species, with chemical structures combining an aliphatic hydrocarbon chain and an aromatic ring with characteristic hydroxyl substituents. Here, we aimed to isolate and characterize the enzyme that forms the alkylresorcinols accumulating in the cuticular wax on the surface of all above-ground organs of rye. Based on sequence homology with other type-III polyketide synthases, a candidate alkylresorcinol synthase was cloned. Yeast heterologous expression showed that the enzyme, ScARS, is highly specific for the formation of the aromatic resorcinol ring structure, through aldol condensation analogous to stilbene synthases. The enzyme accepts long-chain and very-long-chain acyl-CoA starter substrates, preferring saturated over unsaturated chains. It typically carries out three rounds of condensation with malonyl-CoA prior to cyclization, with only very minor activity for a fourth round of malonyl-CoA condensation and cyclization to 5-(2'-oxo)-alkylresorcinols or 5-(2'-hydroxy)-alkylresorcinols. Like other enzymes involved in cuticle formation, ScARS is localized to the endoplasmic reticulum. ScARS expression patterns were found correlated with alkylresorcinol accumulation during leaf development and across different rye organs. Overall, our results thus suggest that ScARS synthesizes the cuticular alkylresorcinols found on diverse rye organ surfaces.
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Affiliation(s)
- Yulin Sun
- Department of Botany, University of British Columbia, 6270 University Blvd., Vancouver, V6T 1Z4, Canada
| | - Ruonan Yao
- Department of Botany, University of British Columbia, 6270 University Blvd., Vancouver, V6T 1Z4, Canada
| | - Xiufeng Ji
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, V6T 1Z1, Canada
| | - Hongqi Wu
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Alvaro Luna
- Department of Botany, University of British Columbia, 6270 University Blvd., Vancouver, V6T 1Z4, Canada
| | - Zhonghua Wang
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Reinhard Jetter
- Department of Botany, University of British Columbia, 6270 University Blvd., Vancouver, V6T 1Z4, Canada
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, V6T 1Z1, Canada
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20
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Mapelli-Brahm A, Sánchez R, Pan X, Moreno-Pérez AJ, Garcés R, Martínez-Force E, Weselake RJ, Salas JJ, Venegas-Calerón M. Functional Characterization of Lysophosphatidylcholine: Acyl-CoA Acyltransferase Genes From Sunflower ( Helianthus annuus L.). FRONTIERS IN PLANT SCIENCE 2020; 11:403. [PMID: 32351524 PMCID: PMC7176023 DOI: 10.3389/fpls.2020.00403] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 03/20/2020] [Indexed: 05/05/2023]
Abstract
Lysophosphatidylcholine acyltransferase (LPCAT, EC 2.3.1.23) is an evolutionarily conserved key enzyme in the Lands cycle that catalyzes acylation of lysophosphatidylcholine (LPC) to produce phosphatidylcholine (PC), the main phospholipid in cellular membranes. In this study, three LPCAT genes from sunflower were identified and the corresponding proteins characterized. These HaLPCAT genes encoded functionally active enzymes that were able to complement a deficient yeast mutant. Moreover, enzymatic assays were carried out using microsomal preparations of the yeast cells. When acyl specificities were measured in the forward reaction, these enzymes exhibited a substrate preference for unsaturated acyl-CoAs, especially for linolenoyl-CoA, while in the reverse reaction, linoleoyl or linolenoyl acyl groups were transferred from PC to acyl-CoA to a similar extent. Expression levels of LPCAT genes were studied revealing distinct tissue-specific expression patterns. In summary, this study suggests that the combined forward and reverse reactions catalyzed by sunflower LPCATs facilitate acyl-exchange between the sn-2 position of PC and the acyl-CoA pool. Sunflower LPCATs displayed different characteristics, which could point to different functionalities, favoring the enrichment of seed triacylglycerols (TAGs) with polyunsaturated fatty acid (PUFA).
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Affiliation(s)
- Ana Mapelli-Brahm
- Instituto de la Grasa (CSIC), Campus Universitario Pablo de Olavide, Seville, Spain
- Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, AB, Canada
| | - Rosario Sánchez
- Instituto de la Grasa (CSIC), Campus Universitario Pablo de Olavide, Seville, Spain
| | - Xue Pan
- Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, AB, Canada
| | | | - Rafael Garcés
- Instituto de la Grasa (CSIC), Campus Universitario Pablo de Olavide, Seville, Spain
| | | | - Randall J. Weselake
- Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, AB, Canada
| | - Joaquín J. Salas
- Instituto de la Grasa (CSIC), Campus Universitario Pablo de Olavide, Seville, Spain
- *Correspondence: Joaquín J. Salas,
| | - Mónica Venegas-Calerón
- Instituto de la Grasa (CSIC), Campus Universitario Pablo de Olavide, Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
- Mónica Venegas-Calerón,
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Klińska S, Jasieniecka-Gazarkiewicz K, Banaś A. Acyl-CoA:lysophosphatidylcholine acyltransferases (LPCATs) of Camelina sativa seeds: biochemical properties and function. PLANTA 2019; 250:1655-1670. [PMID: 31407031 DOI: 10.1007/s00425-019-03248-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 07/25/2019] [Indexed: 05/20/2023]
Abstract
The transfer of polyunsaturated fatty acids from phosphatidylcholine to other lipids involves several enzymes. In Camelina sativa seeds, acyl-CoA:lysophosphatidylcholine acyltransferases could be one of the most important players in this process. The transfer of polyunsaturated fatty acids from the location of their synthesis (phosphatidylcholine) to other lipids, e.g., triacylglycerol, remains insufficiently understood. Several enzymes could be involved in this process. One of these enzymes is acyl-CoA:lysophosphatidylcholine acyltransferases (LPCATs). In Camelina sativa seeds, LPCATs could be one of the most important players in this process. Our data clearly indicate that the CsLPCATs present in developing seeds have the potential to transfer almost all polyunsaturated fatty acids synthesised on phosphatidylcholine to the acyl-CoA pool. CsLPCAT activity is the highest at 30 °C, and the enzymes operate well at a pH of 7.0-11.0, with the best activity at a pH of 9.0. The activity of CsLPCATs was inhibited by calcium and magnesium ions at a concentration of 0.05-2 mM. In the forward reaction, CsLPCATs preferentially utilise 18:2-CoA; however, other C18 unsaturated fatty acids are also well accepted. In the backward reactions, there is no clear discrimination between the C18 unsaturated fatty acids utilised by the enzymes for phosphatidylcholine remodelling. The activity of CsLPCATs does not differ much between the stages of seed development.
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Affiliation(s)
- Sylwia Klińska
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307, Gdansk, Poland
| | | | - Antoni Banaś
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307, Gdansk, Poland
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22
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Yu XH, Cai Y, Chai J, Schwender J, Shanklin J. Expression of a Lychee PHOSPHATIDYLCHOLINE:DIACYLGLYCEROL CHOLINEPHOSPHOTRANSFERASE with an Escherichia coli CYCLOPROPANE SYNTHASE Enhances Cyclopropane Fatty Acid Accumulation in Camelina Seeds. PLANT PHYSIOLOGY 2019; 180:1351-1361. [PMID: 31123096 PMCID: PMC6752900 DOI: 10.1104/pp.19.00396] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 04/25/2019] [Indexed: 05/13/2023]
Abstract
Cyclopropane fatty acids (CPAs) are useful feedstocks for biofuels and bioproducts such as lubricants and biodiesel. Our goal is to identify factors that can facilitate the accumulation of CPA in seed triacylglycerol (TAG) storage oil. We hypothesized that the poor metabolism of CPA through the TAG biosynthetic network could be overcome by the addition of enzymes from species that naturally accumulate CPA in their seed oil, such as lychee (Litchi chinensis), which contains approximately 40% CPA in TAG. Our previous work on engineering CPA accumulation in crop and model plants identified a metabolic bottleneck between phosphatidylcholine (PC), the site of CPA biosynthesis, diacylglycerol (DAG), and TAG. Here, we report the cloning and heterologous expression in camelina (Camelina sativa) of a lychee PHOSPHATIDYLCHOLINE:DIACYLGLYCEROL CHOLINEPHOSPHOTRANSFERASE (PDCT), which encodes the enzyme that catalyzes the transfer of the phosphocholine headgroup from PC to DAG. Camelina lines coexpressing LcPDCT and Escherichia coli CYCLOPROPANE SYNTHASE (EcCPS) showed up to a 50% increase of CPA in mature seed, relative to the EcCPS background. Stereospecific lipid compositional analysis showed that the expression of LcPDCT strongly reduced the level of C18:1 substrate at PC-sn-1 and PC-sn-2 (i.e. the sites of CPA synthesis), while the levels of CPA increased in PC-sn-2, DAG-sn-1 and DAG-sn-2, and both sn-1/3 and sn-2 positions in TAG. Taken together, these data suggest that the addition of PDCT facilitates more efficient movement of CPA from PC to DAG and establishes LcPDCT as a useful factor to combine with others to enhance CPA accumulation in plant seed oil.
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Affiliation(s)
- Xiao-Hong Yu
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794
| | - Yuanheng Cai
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794
| | - Jin Chai
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Jorg Schwender
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - John Shanklin
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
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23
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Maraschin FDS, Kulcheski FR, Segatto ALA, Trenz TS, Barrientos-Diaz O, Margis-Pinheiro M, Margis R, Turchetto-Zolet AC. Enzymes of glycerol-3-phosphate pathway in triacylglycerol synthesis in plants: Function, biotechnological application and evolution. Prog Lipid Res 2019; 73:46-64. [DOI: 10.1016/j.plipres.2018.12.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 11/01/2018] [Accepted: 12/01/2018] [Indexed: 01/30/2023]
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Menard GN, Bryant FM, Kelly AA, Craddock CP, Lavagi I, Hassani-Pak K, Kurup S, Eastmond PJ. Natural variation in acyl editing is a determinant of seed storage oil composition. Sci Rep 2018; 8:17346. [PMID: 30478395 PMCID: PMC6255774 DOI: 10.1038/s41598-018-35136-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 10/26/2018] [Indexed: 01/09/2023] Open
Abstract
Seeds exhibit wide variation in the fatty acid composition of their storage oil. However, the genetic basis of this variation is only partially understood. Here we have used a multi-parent advanced generation inter-cross (MAGIC) population to study the genetic control of fatty acid chain length in Arabidopsis thaliana seed oil. We mapped four quantitative trait loci (QTL) for the quantity of the major very long chain fatty acid species 11-eicosenoic acid (20:1), using multiple QTL modelling. Surprisingly, the main-effect QTL does not coincide with FATTY ACID ELONGASE 1 and a parallel genome wide association study suggested that LYSOPHOSPHATIDYLCHOLINE ACYLTRANSFERASE 2 (LPCAT2) is a candidate for this QTL. Regression analysis also suggested that LPCAT2 expression and 20:1 content in seeds of the 19 MAGIC founder accessions are related. LPCAT is a key component of the Lands cycle; an acyl editing pathway that enables acyl-exchange between the acyl-Coenzyme A and phosphatidylcholine precursor pools used for microsomal fatty acid elongation and desaturation, respectively. We Mendelianised the main-effect QTL using biparental chromosome segment substitution lines and carried out complementation tests to show that a single cis-acting polymorphism in the LPCAT2 promoter causes the variation in seed 20:1 content, by altering the LPCAT2 expression level and total LPCAT activity in developing siliques. Our work establishes that oilseed species exhibit natural variation in the enzymic capacity for acyl editing and this contributes to the genetic control of storage oil composition.
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Affiliation(s)
- Guillaume N Menard
- Department of Plant Science, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Fiona M Bryant
- Department of Plant Science, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Amélie A Kelly
- Georg-August-University, Albrecht-von-Haller-Institute for Plant Sciences, Justus-von-Liebig Weg 11, 37077, Göttingen, Germany
| | - Christian P Craddock
- Mt. San Jacinto College, Menifee Valley Campus, 28237 La Piedra Road, Menifee, CA, 92584, USA
| | - Irene Lavagi
- Department of Microbiology and Plant Pathology, University of California Riverside, Riverside, CA, 92521, USA
| | - Keywan Hassani-Pak
- Department of Plant Science, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Smita Kurup
- Department of Plant Science, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Peter J Eastmond
- Department of Plant Science, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK.
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Yu X, Cahoon RE, Horn PJ, Shi H, Prakash RR, Cai Y, Hearney M, Chapman KD, Cahoon EB, Schwender J, Shanklin J. Identification of bottlenecks in the accumulation of cyclic fatty acids in camelina seed oil. PLANT BIOTECHNOLOGY JOURNAL 2018; 16:926-938. [PMID: 28929610 PMCID: PMC5866947 DOI: 10.1111/pbi.12839] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 09/01/2017] [Accepted: 09/14/2017] [Indexed: 05/20/2023]
Abstract
Modified fatty acids (mFA) have diverse uses; for example, cyclopropane fatty acids (CPA) are feedstocks for producing coatings, lubricants, plastics and cosmetics. The expression of mFA-producing enzymes in crop and model plants generally results in lower levels of mFA accumulation than in their natural-occurring source plants. Thus, to further our understanding of metabolic bottlenecks that limit mFA accumulation, we generated transgenic Camelina sativa lines co-expressing Escherichia coli cyclopropane synthase (EcCPS) and Sterculia foetida lysophosphatidic acid acyltransferase (SfLPAT). In contrast to transgenic CPA-accumulating Arabidopsis, CPA accumulation in camelina caused only minor changes in seed weight, germination rate, oil accumulation and seedling development. CPA accumulated to much higher levels in membrane than storage lipids, comprising more than 60% of total fatty acid in both phosphatidylcholine (PC) and phosphatidylethanolamine (PE) versus 26% in diacylglycerol (DAG) and 12% in triacylglycerol (TAG) indicating bottlenecks in the transfer of CPA from PC to DAG and from DAG to TAG. Upon co-expression of SfLPAT with EcCPS, di-CPA-PC increased by ~50% relative to lines expressing EcCPS alone with the di-CPA-PC primarily observed in the embryonic axis and mono-CPA-PC primarily in cotyledon tissue. EcCPS-SfLPAT lines revealed a redistribution of CPA from the sn-1 to sn-2 positions within PC and PE that was associated with a doubling of CPA accumulation in both DAG and TAG. The identification of metabolic bottlenecks in acyl transfer between site of synthesis (phospholipids) and deposition in storage oils (TAGs) lays the foundation for the optimizing CPA accumulation through directed engineering of oil synthesis in target crops.
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Affiliation(s)
- Xiao‐Hong Yu
- Department of Biochemistry and Cell BiologyStony Brook UniversityStony BrookNYUSA
| | - Rebecca E. Cahoon
- Center for Plant Science InnovationDepartment of BiochemistryUniversity of Nebraska‐LincolnLincolnNEUSA
| | - Patrick J. Horn
- Department of Biological SciencesBioDiscovery InstituteUniversity of North TexasDentonTXUSA
- Present address:
DOE‐Plant Research LaboratoryMichigan State UniversityEast LansingMIUSA
| | - Hai Shi
- Biology DepartmentBrookhaven National LaboratoryUptonNYUSA
| | - Richa R. Prakash
- Department of Biochemistry and Cell BiologyStony Brook UniversityStony BrookNYUSA
- Present address:
Department of Natural SciencesSuffolk County Community CollegeBrentwoodNYUSA
| | - Yuanheng Cai
- Department of Biochemistry and Cell BiologyStony Brook UniversityStony BrookNYUSA
| | - Maegan Hearney
- Biology DepartmentBrookhaven National LaboratoryUptonNYUSA
| | - Kent D. Chapman
- Department of Biological SciencesBioDiscovery InstituteUniversity of North TexasDentonTXUSA
| | - Edgar B. Cahoon
- Center for Plant Science InnovationDepartment of BiochemistryUniversity of Nebraska‐LincolnLincolnNEUSA
| | - Jorg Schwender
- Department of Biochemistry and Cell BiologyStony Brook UniversityStony BrookNYUSA
- Biology DepartmentBrookhaven National LaboratoryUptonNYUSA
| | - John Shanklin
- Department of Biochemistry and Cell BiologyStony Brook UniversityStony BrookNYUSA
- Biology DepartmentBrookhaven National LaboratoryUptonNYUSA
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Bioactivity and biotechnological production of punicic acid. Appl Microbiol Biotechnol 2018; 102:3537-3549. [DOI: 10.1007/s00253-018-8883-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 02/18/2018] [Accepted: 02/19/2018] [Indexed: 02/01/2023]
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Yang W, Wang G, Li J, Bates PD, Wang X, Allen DK. Phospholipase Dζ Enhances Diacylglycerol Flux into Triacylglycerol. PLANT PHYSIOLOGY 2017; 174:110-123. [PMID: 28325849 PMCID: PMC5411150 DOI: 10.1104/pp.17.00026] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 03/20/2017] [Indexed: 05/18/2023]
Abstract
Plant seeds are the primary source of triacylglycerols (TAG) for food, feed, fuel, and industrial applications. As TAG is produced from diacylglycerol (DAG), successful engineering strategies to enhance TAG levels have focused on the conversion of DAG to TAG. However, the production of TAG can be limited by flux through the enzymatic reactions that supply DAG. In this study, two Arabidopsis phospholipase Dζ genes (AtPLDζ1 and AtPLDζ2 ) were coexpressed in Camelina sativa to test whether the conversion of phosphatidylcholine to DAG impacts TAG levels in seeds. The resulting transgenic plants produced 2% to 3% more TAG as a component of total seed biomass and had increased 18:3 and 20:1 fatty acid levels relative to wild type. Increased DAG and decreased PC levels were examined through the kinetics of lipid assembly by [14C]acetate and [14C]glycerol incorporation into glycerolipids. [14C]acetate was rapidly incorporated into TAG in both wild-type and overexpression lines, indicating a significant flux of nascent and elongated acyl-CoAs into the sn-3 position of TAG. Stereochemical analysis revealed that newly synthesized fatty acids were preferentially incorporated into the sn-2 position of PC, but the sn-1 position of de novo DAG and indicated similar rates of nascent acyl groups into the Kennedy pathway and acyl editing. [14C]glycerol studies demonstrated PC-derived DAG is the major source of DAG for TAG synthesis in both tissues. The results emphasize that the interconversions of DAG and PC pools can impact oil production and composition.
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Affiliation(s)
- Wenyu Yang
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (W.Y., G.W., J.L., X.W., D.K.A.); USDA-ARS, Plant Genetics Research Unit, St. Louis, Missouri 63132 (W.Y., D.K.A.); Department of Biology, University of Missouri, St. Louis, Missouri 63121 (G.W., X.W.); and Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406 (P.D.B.)
| | - Geliang Wang
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (W.Y., G.W., J.L., X.W., D.K.A.); USDA-ARS, Plant Genetics Research Unit, St. Louis, Missouri 63132 (W.Y., D.K.A.); Department of Biology, University of Missouri, St. Louis, Missouri 63121 (G.W., X.W.); and Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406 (P.D.B.)
| | - Jia Li
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (W.Y., G.W., J.L., X.W., D.K.A.); USDA-ARS, Plant Genetics Research Unit, St. Louis, Missouri 63132 (W.Y., D.K.A.); Department of Biology, University of Missouri, St. Louis, Missouri 63121 (G.W., X.W.); and Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406 (P.D.B.)
| | - Philip D Bates
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (W.Y., G.W., J.L., X.W., D.K.A.); USDA-ARS, Plant Genetics Research Unit, St. Louis, Missouri 63132 (W.Y., D.K.A.); Department of Biology, University of Missouri, St. Louis, Missouri 63121 (G.W., X.W.); and Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406 (P.D.B.)
| | - Xuemin Wang
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (W.Y., G.W., J.L., X.W., D.K.A.); USDA-ARS, Plant Genetics Research Unit, St. Louis, Missouri 63132 (W.Y., D.K.A.); Department of Biology, University of Missouri, St. Louis, Missouri 63121 (G.W., X.W.); and Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406 (P.D.B.)
| | - Doug K Allen
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (W.Y., G.W., J.L., X.W., D.K.A.); USDA-ARS, Plant Genetics Research Unit, St. Louis, Missouri 63132 (W.Y., D.K.A.); Department of Biology, University of Missouri, St. Louis, Missouri 63121 (G.W., X.W.); and Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406 (P.D.B.)
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Wang N, Ma J, Pei W, Wu M, Li H, Li X, Yu S, Zhang J, Yu J. A genome-wide analysis of the lysophosphatidate acyltransferase (LPAAT) gene family in cotton: organization, expression, sequence variation, and association with seed oil content and fiber quality. BMC Genomics 2017; 18:218. [PMID: 28249560 PMCID: PMC5333453 DOI: 10.1186/s12864-017-3594-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 02/15/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Lysophosphatidic acid acyltransferase (LPAAT) encoded by a multigene family is a rate-limiting enzyme in the Kennedy pathway in higher plants. Cotton is the most important natural fiber crop and one of the most important oilseed crops. However, little is known on genes coding for LPAATs involved in oil biosynthesis with regard to its genome organization, diversity, expression, natural genetic variation, and association with fiber development and oil content in cotton. RESULTS In this study, a comprehensive genome-wide analysis in four Gossypium species with genome sequences, i.e., tetraploid G. hirsutum- AD1 and G. barbadense- AD2 and its possible ancestral diploids G. raimondii- D5 and G. arboreum- A2, identified 13, 10, 8, and 9 LPAAT genes, respectively, that were divided into four subfamilies. RNA-seq analyses of the LPAAT genes in the widely grown G. hirsutum suggest their differential expression at the transcriptional level in developing cottonseeds and fibers. Although 10 LPAAT genes were co-localised with quantitative trait loci (QTL) for cottonseed oil or protein content within a 25-cM region, only one single strand conformation polymorphic (SSCP) marker developed from a synonymous single nucleotide polymorphism (SNP) of the At-Gh13LPAAT5 gene was significantly correlated with cottonseed oil and protein contents in one of the three field tests. Moreover, transformed yeasts using the At-Gh13LPAAT5 gene with the two sequences for the SNP led to similar results, i.e., a 25-31% increase in palmitic acid and oleic acid, and a 16-29% increase in total triacylglycerol (TAG). CONCLUSIONS The results in this study demonstrated that the natural variation in the LPAAT genes to improving cottonseed oil content and fiber quality is limited; therefore, traditional cross breeding should not expect much progress in improving cottonseed oil content or fiber quality through a marker-assisted selection for the LPAAT genes. However, enhancing the expression of one of the LPAAT genes such as At-Gh13LPAAT5 can significantly increase the production of total TAG and other fatty acids, providing an incentive for further studies into the use of LPAAT genes to increase cottonseed oil content through biotechnology.
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Affiliation(s)
- Nuohan Wang
- National Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.,College of Agronomy, Northwest A&F University, Yangling, 712100, China
| | - Jianjiang Ma
- National Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.,College of Agronomy, Northwest A&F University, Yangling, 712100, China
| | - Wenfeng Pei
- National Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China
| | - Man Wu
- National Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China
| | - Haijing Li
- National Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China
| | - Xingli Li
- National Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China
| | - Shuxun Yu
- National Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China. .,College of Agronomy, Northwest A&F University, Yangling, 712100, China.
| | - Jinfa Zhang
- Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces, 880033, USA.
| | - Jiwen Yu
- National Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
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Miklaszewska M, Banaś A, Królicka A. Metabolic engineering of fatty alcohol production in transgenic hairy roots of Crambe abyssinica. Biotechnol Bioeng 2017; 114:1275-1282. [PMID: 27943249 DOI: 10.1002/bit.26234] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 11/20/2016] [Accepted: 12/07/2016] [Indexed: 12/12/2022]
Abstract
Biotechnological production of fatty alcohols, important raw materials in the chemical industry, has been receiving considerable attention in recent years. Fatty alcohols are formed by the reduction of fatty acyl-CoAs or fatty acyl-ACPs catalyzed by a fatty acyl reductase (FAR). In this study, we introduced genes encoding FARs from Arabidopsis thaliana (AtFAR5) and Simmondsia chinensis (ScFAR) into Crambe abyssinica hairy roots via Agrobacterium rhizogenes-mediated transformation. The efficiency of the transformation ranged between 30 and 45%. The fatty alcohols were only detected in the transgenic hairy root lines expressing ScFAR gene. In all tested lines stearyl alcohol (18:0-OH), arachidyl alcohol (20:0-OH), and behenyl alcohol (22:0-OH) were produced. The content of 18:0-OH varied from 1 to 3% of total fatty acids and fatty alcohols, while the amount of either 20:0-OH and 22:0-OH did not exceed 2%. The transgenic hairy root lines produced from 0.98 to 2.59 nmol of fatty alcohols per mg of dry weight. Very low activity of ScFAR was detected in the microsomal fractions isolated from the selected hairy root lines. To our knowledge, this is the first report on the fatty alcohol production in the hairy root cultures. Biotechnol. Bioeng. 2017;114: 1275-1282. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Magdalena Miklaszewska
- Department of Plant Physiology and Biotechnology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland
| | - Antoni Banaś
- Laboratory of Plant Biochemistry, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdańsk, Abrahama, Gdańsk, Poland
| | - Aleksandra Królicka
- Laboratory of Biologically Active Compounds, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdańsk, Abrahama, Gdańsk, Poland
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30
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Allen JW, DiRusso CC, Black PN. Carbon and Acyl Chain Flux during Stress-induced Triglyceride Accumulation by Stable Isotopic Labeling of the Polar Microalga Coccomyxa subellipsoidea C169. J Biol Chem 2016; 292:361-374. [PMID: 27903654 DOI: 10.1074/jbc.m116.760843] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/29/2016] [Indexed: 01/06/2023] Open
Abstract
Deriving biofuels and other lipoid products from algae is a promising future technology directly addressing global issues of atmospheric CO2 balance. To better understand the metabolism of triglyceride synthesis in algae, we examined their metabolic origins in the model species, Coccomyxa subellipsoidea C169, using stable isotopic labeling. Labeling patterns arising from [U-13C]glucose, 13CO2, or D2O supplementation were analyzed by GC-MS and/or LC-MS over time courses during nitrogen starvation to address the roles of catabolic carbon recycling, acyl chain redistribution, and de novo fatty acid (FA) synthesis during the expansion of the lipid bodies. The metabolic origin of stress-induced triglyceride was found to be a continuous 8:2 ratio between de novo synthesized FA and acyl chain transfer from pre-stressed membrane lipids with little input from lipid remodeling. Membrane lipids were continually synthesized with associated acyl chain editing during nitrogen stress, in contrast to an overall decrease in total membrane lipid. The incorporation rates of de novo synthesized FA into lipid classes were measured over a time course of nitrogen starvation. The synthesis of triglycerides, phospholipids, and galactolipids followed a two-stage pattern where nitrogen starvation resulted in a 2.5-fold increase followed by a gradual decline. Acyl chain flux into membrane lipids was dominant in the first stage followed by triglycerides. These data indicate that the level of metabolic control that determines acyl chain flux between membrane lipids and triglycerides during nitrogen stress relies primarily on the Kennedy pathway and de novo FA synthesis with limited, defined input from acyl editing reactions.
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Affiliation(s)
- James W Allen
- From the Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588-0664
| | - Concetta C DiRusso
- From the Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588-0664
| | - Paul N Black
- From the Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588-0664
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Lung SC, Chye ML. Deciphering the roles of acyl-CoA-binding proteins in plant cells. PROTOPLASMA 2016; 253:1177-95. [PMID: 26340904 DOI: 10.1007/s00709-015-0882-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 08/21/2015] [Indexed: 05/18/2023]
Abstract
Lipid trafficking is vital for metabolite exchange and signal communications between organelles and endomembranes. Acyl-CoA-binding proteins (ACBPs) are involved in the intracellular transport, protection, and pool formation of acyl-CoA esters, which are important intermediates and regulators in lipid metabolism and cellular signaling. In this review, we highlight recent advances in our understanding of plant ACBP families from a cellular and developmental perspective. Plant ACBPs have been extensively studied in Arabidopsis thaliana (a dicot) and to a lesser extent in Oryza sativa (a monocot). Thus far, they have been detected in the plasma membrane, vesicles, endoplasmic reticulum, Golgi apparatus, apoplast, cytosol, nuclear periphery, and peroxisomes. In combination with biochemical and molecular genetic tools, the widespread subcellular distribution of respective ACBP members has been explicitly linked to their functions in lipid metabolism during development and in response to stresses. At the cellular level, strong expression of specific ACBP homologs in specialized cells, such as embryos, stem epidermis, guard cells, male gametophytes, and phloem sap, is of relevance to their corresponding distinct roles in organ development and stress responses. Other interesting patterns in their subcellular localization and spatial expression that prompt new directions in future investigations are discussed.
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Affiliation(s)
- Shiu-Cheung Lung
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Mee-Len Chye
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
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Kim HU, Lee KR, Shim D, Lee JH, Chen GQ, Hwang S. Transcriptome analysis and identification of genes associated with ω-3 fatty acid biosynthesis in Perilla frutescens (L.) var. frutescens. BMC Genomics 2016; 17:474. [PMID: 27342315 PMCID: PMC4920993 DOI: 10.1186/s12864-016-2805-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 05/27/2016] [Indexed: 12/02/2022] Open
Abstract
Background Perilla (Perilla frutescens (L.) var frutescens) produces high levels of α-linolenic acid (ALA), a ω-3 fatty acid important to health and development. To uncover key genes involved in fatty acid (FA) and triacylglycerol (TAG) synthesis in perilla, we conducted deep sequencing of cDNAs from developing seeds and leaves for understanding the mechanism underlying ALA and seed TAG biosynthesis. Results Perilla cultivar Dayudeulkkae contains 66.0 and 56.2 % ALA in seeds and leaves, respectively. Using Illumina HiSeq 2000, we have generated a total of 392 megabases of raw sequences from four mRNA samples of seeds at different developmental stages and one mature leaf sample of Dayudeulkkae. De novo assembly of these sequences revealed 54,079 unique transcripts, of which 32,237 belong to previously annotated genes. Among the annotated genes, 66.5 % (21,429 out of 32,237) showed highest sequences homology with the genes from Mimulus guttatus, a species placed under the same Lamiales order as perilla. Using Arabidopsis acyl-lipid genes as queries, we searched the transcriptome and identified 540 unique perilla genes involved in all known pathways of acyl-lipid metabolism. We characterized the expression profiles of 43 genes involved in FA and TAG synthesis using quantitative PCR. Key genes were identified through sequence and gene expression analyses. Conclusions This work is the first report on building transcriptomes from perilla seeds. The work also provides the first comprehensive expression profiles for genes involved in seed oil biosynthesis. Bioinformatic analysis indicated that our sequence collection represented a major transcriptomic resource for perilla that added valuable genetic information in order Lamiales. Our results provide critical information not only for studies of the mechanisms involved in ALA synthesis, but also for biotechnological production of ALA in other oilseeds. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2805-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hyun Uk Kim
- Department of Bioindustry and Bioresource Engineering, Plant Engineering Research Institute, Sejong University, Seoul, 05006, Republic of Korea.
| | - Kyeong-Ryeol Lee
- Department of Agricultural Biotechnology, National Institute of Agricultural Science, Rural Development Administration, Jeonju, 54874, Republic of Korea
| | - Donghwan Shim
- Department of Forest Genetic Resources, National Institute of Forest Science, Suwon, 16631, Republic of Korea
| | | | - Grace Q Chen
- U.S. Department of Agriculture, Western Regional Research Center, Agricultural Research Service, 800 Buchanan Street, Albany, CA, 94710, USA
| | - Seongbin Hwang
- Department of Bioindustry and Bioresource Engineering, Plant Engineering Research Institute, Sejong University, Seoul, 05006, Republic of Korea
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Kim HU, Lee KR, Shim D, Lee JH, Chen GQ, Hwang S. Transcriptome analysis and identification of genes associated with ω-3 fatty acid biosynthesis in Perilla frutescens (L.) var. frutescens. BMC Genomics 2016; 17:474. [PMID: 27342315 DOI: 10.1186/s12864-016-2805-2800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 05/27/2016] [Indexed: 05/24/2023] Open
Abstract
BACKGROUND Perilla (Perilla frutescens (L.) var frutescens) produces high levels of α-linolenic acid (ALA), a ω-3 fatty acid important to health and development. To uncover key genes involved in fatty acid (FA) and triacylglycerol (TAG) synthesis in perilla, we conducted deep sequencing of cDNAs from developing seeds and leaves for understanding the mechanism underlying ALA and seed TAG biosynthesis. RESULTS Perilla cultivar Dayudeulkkae contains 66.0 and 56.2 % ALA in seeds and leaves, respectively. Using Illumina HiSeq 2000, we have generated a total of 392 megabases of raw sequences from four mRNA samples of seeds at different developmental stages and one mature leaf sample of Dayudeulkkae. De novo assembly of these sequences revealed 54,079 unique transcripts, of which 32,237 belong to previously annotated genes. Among the annotated genes, 66.5 % (21,429 out of 32,237) showed highest sequences homology with the genes from Mimulus guttatus, a species placed under the same Lamiales order as perilla. Using Arabidopsis acyl-lipid genes as queries, we searched the transcriptome and identified 540 unique perilla genes involved in all known pathways of acyl-lipid metabolism. We characterized the expression profiles of 43 genes involved in FA and TAG synthesis using quantitative PCR. Key genes were identified through sequence and gene expression analyses. CONCLUSIONS This work is the first report on building transcriptomes from perilla seeds. The work also provides the first comprehensive expression profiles for genes involved in seed oil biosynthesis. Bioinformatic analysis indicated that our sequence collection represented a major transcriptomic resource for perilla that added valuable genetic information in order Lamiales. Our results provide critical information not only for studies of the mechanisms involved in ALA synthesis, but also for biotechnological production of ALA in other oilseeds.
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Affiliation(s)
- Hyun Uk Kim
- Department of Bioindustry and Bioresource Engineering, Plant Engineering Research Institute, Sejong University, Seoul, 05006, Republic of Korea.
| | - Kyeong-Ryeol Lee
- Department of Agricultural Biotechnology, National Institute of Agricultural Science, Rural Development Administration, Jeonju, 54874, Republic of Korea
| | - Donghwan Shim
- Department of Forest Genetic Resources, National Institute of Forest Science, Suwon, 16631, Republic of Korea
| | | | - Grace Q Chen
- U.S. Department of Agriculture, Western Regional Research Center, Agricultural Research Service, 800 Buchanan Street, Albany, CA, 94710, USA
| | - Seongbin Hwang
- Department of Bioindustry and Bioresource Engineering, Plant Engineering Research Institute, Sejong University, Seoul, 05006, Republic of Korea
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Bates PD. Understanding the control of acyl flux through the lipid metabolic network of plant oil biosynthesis. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1214-1225. [PMID: 27003249 DOI: 10.1016/j.bbalip.2016.03.021] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 10/22/2022]
Abstract
Plant oil biosynthesis involves a complex metabolic network with multiple subcellular compartments, parallel pathways, cycles, and pathways that have a dual function to produce essential membrane lipids and triacylglycerol. Modern molecular biology techniques provide tools to alter plant oil compositions through bioengineering, however with few exceptions the final composition of triacylglycerol cannot be predicted. One reason for limited success in oilseed bioengineering is the inadequate understanding of how to control the flux of fatty acids through various fatty acid modification, and triacylglycerol assembly pathways of the lipid metabolic network. This review focuses on the mechanisms of acyl flux through the lipid metabolic network, and highlights where uncertainty resides in our understanding of seed oil biosynthesis. This article is part of a Special Issue entitled: Plant Lipid Biology edited by Kent D. Chapman and Ivo Feussner.
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Affiliation(s)
- Philip D Bates
- Department of Chemistry and Biochemistry, The University of Southern Mississippi, 118 College Dr. #5043, Hattiesburg, MS 39406-0001, United States.
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Shockey J, Regmi A, Cotton K, Adhikari N, Browse J, Bates PD. Identification of Arabidopsis GPAT9 (At5g60620) as an Essential Gene Involved in Triacylglycerol Biosynthesis. PLANT PHYSIOLOGY 2016; 170:163-79. [PMID: 26586834 PMCID: PMC4704598 DOI: 10.1104/pp.15.01563] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 11/19/2015] [Indexed: 05/20/2023]
Abstract
The first step in the biosynthesis of nearly all plant membrane phospholipids and storage triacylglycerols is catalyzed by a glycerol-3-phosphate acyltransferase (GPAT). The requirement for an endoplasmic reticulum (ER)-localized GPAT for both of these critical metabolic pathways was recognized more than 60 years ago. However, identification of the gene(s) encoding this GPAT activity has remained elusive. Here, we present the results of a series of in vivo, in vitro, and in silico experiments in Arabidopsis (Arabidopsis thaliana) designed to assign this essential function to AtGPAT9. This gene has been highly conserved throughout evolution and is largely present as a single copy in most plants, features consistent with essential housekeeping functions. A knockout mutant of AtGPAT9 demonstrates both male and female gametophytic lethality phenotypes, consistent with the role in essential membrane lipid synthesis. Significant expression of developing seed AtGPAT9 is required for wild-type levels of triacylglycerol accumulation, and the transcript level is directly correlated to the level of microsomal GPAT enzymatic activity in seeds. Finally, the AtGPAT9 protein interacts with other enzymes involved in ER glycerolipid biosynthesis, suggesting the possibility of ER-localized lipid biosynthetic complexes. Together, these results suggest that GPAT9 is the ER-localized GPAT enzyme responsible for plant membrane lipid and oil biosynthesis.
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Affiliation(s)
- Jay Shockey
- U.S. Department of Agriculture-Agricultural Research Service, Southern Regional Research Center, New Orleans, Louisiana 70124 (J.S.);Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406 (A.R., P.D.B.); andInstitute of Biological Chemistry, Washington State University, Pullman, Washington 99163 (K.C., N.A., J.B.)
| | - Anushobha Regmi
- U.S. Department of Agriculture-Agricultural Research Service, Southern Regional Research Center, New Orleans, Louisiana 70124 (J.S.);Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406 (A.R., P.D.B.); andInstitute of Biological Chemistry, Washington State University, Pullman, Washington 99163 (K.C., N.A., J.B.)
| | - Kimberly Cotton
- U.S. Department of Agriculture-Agricultural Research Service, Southern Regional Research Center, New Orleans, Louisiana 70124 (J.S.);Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406 (A.R., P.D.B.); andInstitute of Biological Chemistry, Washington State University, Pullman, Washington 99163 (K.C., N.A., J.B.)
| | - Neil Adhikari
- U.S. Department of Agriculture-Agricultural Research Service, Southern Regional Research Center, New Orleans, Louisiana 70124 (J.S.);Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406 (A.R., P.D.B.); andInstitute of Biological Chemistry, Washington State University, Pullman, Washington 99163 (K.C., N.A., J.B.)
| | - John Browse
- U.S. Department of Agriculture-Agricultural Research Service, Southern Regional Research Center, New Orleans, Louisiana 70124 (J.S.);Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406 (A.R., P.D.B.); andInstitute of Biological Chemistry, Washington State University, Pullman, Washington 99163 (K.C., N.A., J.B.)
| | - Philip D Bates
- U.S. Department of Agriculture-Agricultural Research Service, Southern Regional Research Center, New Orleans, Louisiana 70124 (J.S.);Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406 (A.R., P.D.B.); andInstitute of Biological Chemistry, Washington State University, Pullman, Washington 99163 (K.C., N.A., J.B.)
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Abstract
Acyl-CoA-binding proteins (ACBPs) play a pivotal role in fatty acid metabolism because they can transport medium- and long-chain acyl-CoA esters. In eukaryotic cells, ACBPs are involved in intracellular trafficking of acyl-CoA esters and formation of a cytosolic acyl-CoA pool. In addition to these ubiquitous functions, more specific non-redundant roles of plant ACBP subclasses are implicated by the existence of multigene families with variable molecular masses, ligand specificities, functional domains (e.g. protein-protein interaction domains), subcellular locations and gene expression patterns. In this chapter, recent progress in the characterization of ACBPs from the model dicot plant, Arabidopsis thaliana, and the model monocot, Oryza sativa, and their emerging roles in plant growth and development are discussed. The functional significance of respective members of the plant ACBP families in various developmental and physiological processes such as seed development and germination, stem cuticle formation, pollen development, leaf senescence, peroxisomal fatty acid β-oxidation and phloem-mediated lipid transport is highlighted.
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Affiliation(s)
- Shiu-Cheung Lung
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Mee-Len Chye
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
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Lung SC, Chye ML. The binding versatility of plant acyl-CoA-binding proteins and their significance in lipid metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1861:1409-1421. [PMID: 26747650 DOI: 10.1016/j.bbalip.2015.12.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 12/28/2015] [Accepted: 12/29/2015] [Indexed: 11/18/2022]
Abstract
Acyl-CoA esters are the activated form of fatty acids and play important roles in lipid metabolism and the regulation of cell functions. They are bound and transported by nonenzymic proteins such as the acyl-CoA-binding proteins (ACBPs). Although plant ACBPs were so named by virtue of amino acid homology to existing yeast and mammalian counterparts, recent studies revealed that ligand specificities of plant ACBPs are not restricted to acyl-CoA esters. Arabidopsis and rice ACBPs also interact with phospholipids, and their affinities to different acyl-CoA species and phospholipid classes vary amongst isoforms. Their ligands also include heavy metals. Interactors of plant ACBPs are further diversified due to the evolution of protein-protein interacting domains. This review summarizes our current understanding of plant ACBPs with a focus on their binding versatility. Their broad ligand range is of paramount significance in serving a multitude of functions during development and stress responses as discussed herein. This article is part of a Special Issue entitled: Plant Lipid Biology edited by Kent D. Chapman and Ivo Feussner.
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Affiliation(s)
- Shiu-Cheung Lung
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
| | - Mee-Len Chye
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
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Zhang D, Jasieniecka-Gazarkiewicz K, Wan X, Luo L, Zhang Y, Banas A, Jiang M, Gong Y. Molecular Characterization of Two Lysophospholipid:acyl-CoA Acyltransferases Belonging to the MBOAT Family in Nicotiana benthamiana. PLoS One 2015; 10:e0144653. [PMID: 26684752 PMCID: PMC4684200 DOI: 10.1371/journal.pone.0144653] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 11/20/2015] [Indexed: 12/03/2022] Open
Abstract
In the remodeling pathway for the synthesis of phosphatidylcholine (PC), acyl-CoA-dependent lysophosphatidylcholine (lysoPC) acyltransferase (LPCAT) catalyzes the reacylation of lysoPC. A number of genes encoding LPCATs have been cloned and characterized from several plants in recent years. Using Arabidopsis and other plant LPCAT sequences to screen the genome database of Nicotiana benthamiana, we identified two cDNAs encoding the putative tobacco LPCATs (NbLPCAT1 and NbLPCAT2). Both of them were predicted to encode a protein of 463 amino acids with high similarity to LPCATs from other plants. Protein sequence features such as the presence of at least eight putative transmembrane regions, four highly conserved signature motifs and several invariant residues indicate that NbLPCATs belong to the membrane bound O-acyltransferase family. Lysophospholipid acyltransferase activity of NbLPCATs was confirmed by testing lyso-platelet-activating factor (lysoPAF) sensitivity through heterologous expression of each full-length cDNA in a yeast mutant Y02431 (lca1△) disrupted in endogenous LPCAT enzyme activity. Analysis of fatty acid profiles of phospholipids from the NbLPCAT-expressing yeast mutant Y02431 cultures supplemented with polyunsaturated fatty acids suggested more incorporation of linoleic acid (18:2n6, LA) and α-linolenic acid (18:3n3, ALA) into PC compared to yeast mutant harbouring empty vector. In vitro enzymatic assay demonstrated that NbLPCAT1had high lysoPC acyltransferase activity with a clear preference for α-linolenoyl-CoA (18:3), while NbLPCAT2 showed a high lysophosphatidic acid (lysoPA) acyltransferase activity towards α-linolenoyl-CoA and a weak lysoPC acyltransferase activity. Tissue-specific expression analysis showed a ubiquitous expression of NbLPCAT1 and NbLPCAT2 in roots, stems, leaves, flowers and seeds, and a strong expression in developing flowers. This is the first report on the cloning and characterization of lysophospholipid acyltransferases from N. benthamiana.
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Affiliation(s)
- Donghui Zhang
- 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
| | | | - Xia Wan
- 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
| | - Ling Luo
- 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
| | - Yinbo Zhang
- 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
| | - Antoni Banas
- Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, 80–822, Gdansk, Poland
| | - Mulan Jiang
- 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
| | - 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
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Abstract
A gene family encoding six members of acyl-CoA-binding proteins (ACBP) exists in Arabidopsis and they are designated as AtACBP1-AtACBP6. They have been observed to play pivotal roles in plant lipid metabolism, consistent to the abilities of recombinant AtACBP in binding different medium- and long-chain acyl-CoA esters in vitro. While AtACBP1 and AtACBP2 are membrane-associated proteins with ankyrin repeats and AtACBP3 contains a signaling peptide for targeting to the apoplast, AtACBP4, AtACBP5 and AtACBP6 represent the cytosolic forms in the AtACBP family. They were verified to be subcellularly localized in the cytosol using diverse experimental methods, including cell fractionation followed by western blot analysis, immunoelectron microscopy and confocal laser-scanning microscopy using autofluorescence-tagged fusions. AtACBP4 (73.2 kDa) and AtACBP5 (70.1 kDa) are the largest, while AtACBP6 (10.4 kDa) is the smallest. Their binding affinities to oleoyl-CoA esters suggested that they can potentially transfer oleoyl-CoA esters from the plastids to the endoplasmic reticulum, facilitating the subsequent biosynthesis of non-plastidial membrane lipids in Arabidopsis. Recent studies on ACBP, extended from a dicot (Arabidopsis) to a monocot, revealed that six ACBP are also encoded in rice (Oryza sativa). Interestingly, three small rice ACBP (OsACBP1, OsACBP2 and OsACBP3) are present in the cytosol in comparison to one (AtACBP6) in Arabidopsis. In this review, the combinatory and distinct roles of the cytosolic AtACBP are discussed, including their functions in pollen and seed development, light-dependent regulation and substrate affinities to acyl-CoA esters.
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Jasieniecka-Gazarkiewicz K, Demski K, Lager I, Stymne S, Banaś A. Possible Role of Different Yeast and Plant Lysophospholipid:Acyl-CoA Acyltransferases (LPLATs) in Acyl Remodelling of Phospholipids. Lipids 2015; 51:15-23. [PMID: 26643989 PMCID: PMC4700060 DOI: 10.1007/s11745-015-4102-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 11/12/2015] [Indexed: 12/02/2022]
Abstract
Recent results have suggested that plant lysophosphatidylcholine:acyl-coenzyme A acyltransferases (LPCATs) can operate in reverse in vivo and thereby catalyse an acyl exchange between the acyl-coenzyme A (CoA) pool and the phosphatidylcholine. We have investigated the abilities of Arabidopsis AtLPCAT2, Arabidopsis lysophosphatidylethanolamine acyltransferase (LPEAT2), S. cerevisiae lysophospholipid acyltransferase (Ale1) and S. cerevisiae lysophosphatidic acid acyltransferase (SLC1) to acylate lysoPtdCho, lysoPtdEtn and lysoPtdOH and act reversibly on the products of the acylation; the PtdCho, PtdEtn and PtdOH. The tested LPLATs were expressed in an S. cervisiaeale1 strain and enzyme activities were assessed in assays using microsomal preparations of the different transformants. The results show that, despite high activity towards lysoPtdCho, lysoPtdEtn and lysoPtdOH by the ALE1, its capacities to operate reversibly on the products of the acylation were very low. Slc1 readily acylated lysoPtdOH, lysoPtdCho and lysoPtdEtn but showed no reversibility towards PtdCho, very little reversibility towards PtdEtn and very high reversibility towards PtdOH. LPEAT2 showed the highest levels of reversibility towards PtdCho and PtdEtn of all LPLATs tested but low ability to operate reversibly on PtdOH. AtLPCAT2 showed good reversible activity towards PtdCho and PtdEtn and very low reversibility towards PtdOH. Thus, it appears that some of the LPLATs have developed properties that, to a much higher degree than other LPLATs, promote the reverse reaction during the same assay conditions and with the same phospholipid. The results also show that the capacity of reversibility can be specific for a particular phospholipid, albeit the lysophospholipid derivatives of other phospholipids serve as good acyl acceptors for the forward reaction of the enzyme.
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Affiliation(s)
| | - Kamil Demski
- Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Kładki 24, 80-822, Gdańsk, Poland
| | - Ida Lager
- Department of Plant Breeding, Swedish University of Agricultural Sciences, 230 53, Alnarp, Sweden
| | - Sten Stymne
- Department of Plant Breeding, Swedish University of Agricultural Sciences, 230 53, Alnarp, Sweden
| | - Antoni Banaś
- Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Kładki 24, 80-822, Gdańsk, Poland.
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Pan X, Chen G, Kazachkov M, Greer MS, Caldo KMP, Zou J, Weselake RJ. In Vivo and in Vitro Evidence for Biochemical Coupling of Reactions Catalyzed by Lysophosphatidylcholine Acyltransferase and Diacylglycerol Acyltransferase. J Biol Chem 2015; 290:18068-18078. [PMID: 26055703 DOI: 10.1074/jbc.m115.654798] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Indexed: 11/06/2022] Open
Abstract
Seed oils of flax (Linum usitatissimum L.) and many other plant species contain substantial amounts of polyunsaturated fatty acids (PUFAs). Phosphatidylcholine (PC) is the major site for PUFA synthesis. The exact mechanisms of how these PUFAs are channeled from PC into triacylglycerol (TAG) needs to be further explored. By using in vivo and in vitro approaches, we demonstrated that the PC deacylation reaction catalyzed by the reverse action of acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT) can transfer PUFAs on PC directly into the acyl-CoA pool, making these PUFAs available for the diacylglycerol acyltransferase (DGAT)-catalyzed reaction for TAG production. Two types of yeast mutants were generated for in vivo and in vitro experiments, respectively. Both mutants provide a null background with no endogenous TAG forming capacity and an extremely low LPCAT activity. In vivo experiments showed that co-expressing flax DGAT1-1 and LPCAT1 in the yeast quintuple mutant significantly increased 18-carbon PUFAs in TAG with a concomitant decrease of 18-carbon PUFAs in phospholipid. We further showed that after incubation of sn-2-[(14)C]acyl-PC, formation of [(14)C]TAG was only possible with yeast microsomes containing both LPCAT1 and DGAT1-1. Moreover, the specific activity of overall LPCAT1 and DGAT1-1 coupling process exhibited a preference for transferring (14)C-labeled linoleoyl or linolenoyl than oleoyl moieties from the sn-2 position of PC to TAG. Together, our data support the hypothesis of biochemical coupling of the LPCAT1-catalyzed reverse reaction with the DGAT1-1-catalyzed reaction for incorporating PUFAs into TAG. This process represents a potential route for enriching TAG in PUFA content during seed development in flax.
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Affiliation(s)
- Xue Pan
- Alberta Innovates Phytola Centre, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Guanqun Chen
- Alberta Innovates Phytola Centre, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Michael Kazachkov
- National Research Council Canada, Saskatoon, Saskatchewan S7N 0W9, Canada
| | - Michael S Greer
- Alberta Innovates Phytola Centre, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Kristian Mark P Caldo
- Alberta Innovates Phytola Centre, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Jitao Zou
- National Research Council Canada, Saskatoon, Saskatchewan S7N 0W9, Canada
| | - Randall J Weselake
- Alberta Innovates Phytola Centre, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada.
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Bayon S, Chen G, Weselake RJ, Browse J. A small phospholipase A2-α from castor catalyzes the removal of hydroxy fatty acids from phosphatidylcholine in transgenic Arabidopsis seeds. PLANT PHYSIOLOGY 2015; 167:1259-70. [PMID: 25667315 PMCID: PMC4378157 DOI: 10.1104/pp.114.253641] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 02/04/2015] [Indexed: 05/21/2023]
Abstract
Ricinoleic acid, an industrially useful hydroxy fatty acid (HFA), only accumulates to high levels in the triacylglycerol fraction of castor (Ricinus communis) endosperm, even though it is synthesized on the membrane lipid phosphatidylcholine (PC) from an oleoyl ester. The acyl chains of PC undergo intense remodeling through the process of acyl editing. The identities of the proteins involved in this process, however, are unknown. A phospholipase A2 (PLA2) is thought to be involved in the acyl-editing process. We show here a role for RcsPLA2α in the acyl editing of HFA esterified to PC. RcsPLA2α was identified by its high relative expression in the castor endosperm transcriptome. Coexpression in Arabidopsis (Arabidopsis thaliana) seeds of RcsPLA2α with the castor fatty acid hydroxylase RcFAH12 led to a dramatic decrease in seed HFA content when compared with RcFAH12 expression alone in both PC and the neutral lipid fraction. The low-HFA trait was heritable and gene dosage dependent, with hemizygous lines showing intermediate HFA levels. The low seed HFA levels suggested that RcsPLA2α functions in vivo as a PLA2 with HFA specificity. Activity assays with yeast (Saccharomyces cerevisiae) microsomes showed a high specificity of RcsPLA2α for ricinoleic acid, superior to that of the endogenous Arabidopsis PLA2α. These results point to RcsPLA2α as a phospholipase involved in acyl editing, adapted to specifically removing HFA from membrane lipids in seeds.
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Affiliation(s)
- Shen Bayon
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (S.B., J.B.); andAlberta Innovates Phytola Centre, Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5 (G.C., R.J.W.)
| | - Guanqun Chen
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (S.B., J.B.); andAlberta Innovates Phytola Centre, Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5 (G.C., R.J.W.)
| | - Randall J Weselake
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (S.B., J.B.); andAlberta Innovates Phytola Centre, Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5 (G.C., R.J.W.)
| | - John Browse
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 (S.B., J.B.); andAlberta Innovates Phytola Centre, Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5 (G.C., R.J.W.)
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Lee KR, Chen GQ, Kim HU. Current progress towards the metabolic engineering of plant seed oil for hydroxy fatty acids production. PLANT CELL REPORTS 2015; 34:603-615. [PMID: 25577331 DOI: 10.1007/s00299-015-1736-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 12/30/2014] [Indexed: 06/04/2023]
Abstract
Hydroxy fatty acids produced in plant seed oil are important industrial material. This review focuses on the use of metabolic engineering approaches for the production of hydroxy fatty acids in transgenic plants. Vegetable oil is not only edible but can also be used for industrial purposes. The industrial demand for vegetable oil will increase with the continued depletion of fossil fuels and ensuing environmental issues such as climate change, caused by increased carbon dioxide in the air. Some plants accumulate high levels of unusual fatty acids in their seeds, and these fatty acids (FAs) have properties that make them suitable for industrial applications. Hydroxy fatty acids (HFAs) are some of the most important of these industrial FAs. Castor oil is the conventional source of HFA. However, due to the presence of toxin ricin in its seeds, castor is not cultivated on a large scale. Lesquerella is another HFA accumulator and is currently being developed as a new crop for a safe source of HFAs. The mechanisms of HFA synthesis and accumulation have been extensively studied using castor genes and the model plant Arabidopsis. HFAs accumulated to 17% in the seed oil of Arabidopsis expressing a FA hydroxylase gene from castor (RcFAH12), but its seed oil content and plant growth decreased. When RcFAH12 gene was coexpressed with additional castor gene(s) in Arabidopsis, ~30% HFAs were accumulated and the seed oil content and plant growth was almost restored to the wild-type level. Further advancement of our understanding of pathways, genes and regulatory mechanisms underlying synthesis and accumulation of HFAs is essential to developing and implementing effective genetic approaches for enhancing HFA production in oilseeds.
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Affiliation(s)
- Kyeong-Ryeol Lee
- Department of Agricultural Biotechnology, National Academy of Agricultural Science, Rural Development Administration, Jeonju, 560-500, Republic of Korea
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Kim HU, Chen GQ. Identification of hydroxy fatty acid and triacylglycerol metabolism-related genes in lesquerella through seed transcriptome analysis. BMC Genomics 2015; 16:230. [PMID: 25881190 PMCID: PMC4381405 DOI: 10.1186/s12864-015-1413-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Accepted: 02/27/2015] [Indexed: 12/04/2022] Open
Abstract
Background Castor oil is the only commercial source of hydroxy fatty acid that has industrial value. The production of castor oil is hampered by the presence of the toxin ricin in its seed. Lesquerella seed also accumulates hydroxy fatty acid and is free of ricin, and thus it is being developed as a new crop for hydroxy fatty acid production. A high-throughput, large-scale sequencing of transcripts from developing lesquerella seeds was carried out by 454 pyrosequencing to generate a database for quality improvement of seed oil and other agronomic traits. Deep mining and characterization of acyl-lipid genes were conducted to uncover candidate genes for further studies of mechanisms underlying hydroxy fatty acid and seed oil synthesis. Results A total of 651 megabases of raw sequences from an mRNA sample of developing seeds was acquired. Bioinformatic analysis of these sequences revealed 59,914 transcripts representing 26,995 unique genes that include nearly all known seed expressed genes. Based on sequence similarity with known plant proteins, about 74% (19,861) genes matched with annotated coding genes. Among them, 95% (18,868) showed highest sequence homology with Arabidopsis genes, which will allow translation of genomics and genetics findings from Arabidopsis to lesquerella. Using Arabidopsis acyl-lipid genes as queries, we searched the transcriptome assembly and identified 615 lesquerella genes involved in all known pathways of acyl-lipid metabolism. Further deep mining the transcriptome assembly led to identification of almost all lesquerella genes involved in fatty acid and triacylglycerol synthesis. Moreover, we characterized the spatial and temporal expression profiles of 15 key genes using the quantitative PCR assay. Conclusions We have built a lesquerella seed transcriptome that provides a valuable reference in addition to the castor database for discovering genes involved in the synthesis of triacylglycerols enriched with hydroxy fatty acids. The information obtained from data mining and gene expression profiling will provide a resource not only for the study of hydroxy fatty acid metabolism, but also for the biotechnological production of hydroxy fatty acids in existing oilseed crops. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1413-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hyun Uk Kim
- Department of Agricultural Biotechnology, National Academy of Agricultural Science, Rural Development Administration, Jeonju, 560-500, Republic of Korea.
| | - Grace Qianhong Chen
- U.S. Department of Agriculture, Western Regional Research Center, Agricultural Research Service, 800 Buchanan Street, Albany, CA, 94710, USA.
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Allen DK, Bates PD, Tjellström H. Tracking the metabolic pulse of plant lipid production with isotopic labeling and flux analyses: Past, present and future. Prog Lipid Res 2015; 58:97-120. [PMID: 25773881 DOI: 10.1016/j.plipres.2015.02.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 01/30/2015] [Accepted: 02/11/2015] [Indexed: 11/25/2022]
Abstract
Metabolism is comprised of networks of chemical transformations, organized into integrated biochemical pathways that are the basis of cellular operation, and function to sustain life. Metabolism, and thus life, is not static. The rate of metabolites transitioning through biochemical pathways (i.e., flux) determines cellular phenotypes, and is constantly changing in response to genetic or environmental perturbations. Each change evokes a response in metabolic pathway flow, and the quantification of fluxes under varied conditions helps to elucidate major and minor routes, and regulatory aspects of metabolism. To measure fluxes requires experimental methods that assess the movements and transformations of metabolites without creating artifacts. Isotopic labeling fills this role and is a long-standing experimental approach to identify pathways and quantify their metabolic relevance in different tissues or under different conditions. The application of labeling techniques to plant science is however far from reaching it potential. In light of advances in genetics and molecular biology that provide a means to alter metabolism, and given recent improvements in instrumentation, computational tools and available isotopes, the use of isotopic labeling to probe metabolism is becoming more and more powerful. We review the principal analytical methods for isotopic labeling with a focus on seminal studies of pathways and fluxes in lipid metabolism and carbon partitioning through central metabolism. Central carbon metabolic steps are directly linked to lipid production by serving to generate the precursors for fatty acid biosynthesis and lipid assembly. Additionally some of the ideas for labeling techniques that may be most applicable for lipid metabolism in the future were originally developed to investigate other aspects of central metabolism. We conclude by describing recent advances that will play an important future role in quantifying flux and metabolic operation in plant tissues.
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Affiliation(s)
- Doug K Allen
- United States Department of Agriculture, Agricultural Research Service, 975 North Warson Road, St. Louis, MO 63132, United States; Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO 63132, United States.
| | - Philip D Bates
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, MS 39406, United States
| | - Henrik Tjellström
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824, United States; Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824, United States
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RNAi Targeting Putative Genes in Phosphatidylcholine Turnover Results in Significant Change in Fatty Acid Composition in Crambe abyssinica Seed Oil. Lipids 2015; 50:407-16. [DOI: 10.1007/s11745-015-4004-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 02/21/2015] [Indexed: 10/23/2022]
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Tjellström H, Strawsine M, Ohlrogge JB. Tracking synthesis and turnover of triacylglycerol in leaves. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:1453-61. [PMID: 25609824 PMCID: PMC4339603 DOI: 10.1093/jxb/eru500] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Triacylglycerol (TAG), typically represents <1% of leaf glycerolipids but can accumulate under stress and other conditions or if leaves are supplied with fatty acids, or in plants transformed with regulators or enzymes of lipid metabolism. To better understand the metabolism of TAG in leaves, pulse-chase radiolabelling experiments were designed to probe its synthesis and turnover. When Arabidopsis leaves were incubated with [(14)C]lauric acid (12:0), a major initial product was [(14)C]TAG. Thus, despite low steady-state levels, leaves possess substantial TAG biosynthetic capacity. The contributions of diacylglycerol acyltransferase1 and phospholipid:diacylglycerol acyltransferase1 to leaf TAG synthesis were examined by labelling of dgat1 and pdat1 mutants. The dgat1 mutant displayed a major (76%) reduction in [(14)C]TAG accumulation whereas pdat1 TAG labelling was only slightly reduced. Thus, DGAT1 has a principal role in TAG biosynthesis in young leaves. During a 4h chase period, radioactivity in TAG declined 70%, whereas the turnover of [(14)C]acyl chains of phosphatidylcholine (PC) and other polar lipids was much lower. Sixty percent of [(14)C]12:0 was directly incorporated into glycerolipids without modification, whereas 40% was elongated and desaturated to 16:0 and 18:1 by plastids. The unmodified [(14)C]12:0 and the plastid products of [(14)C]12:0 metabolism entered different pathways. Although plastid-modified (14)C-labelled products accumulated in monogalactosyldiacylglycerol, PC, phosphatidylethanolamine, and diacylglcerol (DAG), there was almost no accumulation of [(14)C]16:0 and [(14)C]18:1 in TAG. Because DAG and acyl-CoA are direct precursors of TAG, the differential labelling of polar glycerolipids and TAG by [(14)C]12:0 and its plastid-modified products provides evidence for multiple subcellular pools of both acyl-CoA and DAG.
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Affiliation(s)
- Henrik Tjellström
- Department of Plant Biology and Department of Energy, Great Lakes Bioenergy Research Center Michigan State University, East Lansing, MI 48824, USA
| | - Merissa Strawsine
- Department of Plant Biology and Department of Energy, Great Lakes Bioenergy Research Center Michigan State University, East Lansing, MI 48824, USA
| | - John B Ohlrogge
- Department of Plant Biology and Department of Energy, Great Lakes Bioenergy Research Center Michigan State University, East Lansing, MI 48824, USA
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Lager I, Glab B, Eriksson L, Chen G, Banas A, Stymne S. Novel reactions in acyl editing of phosphatidylcholine by lysophosphatidylcholine transacylase (LPCT) and acyl-CoA:glycerophosphocholine acyltransferase (GPCAT) activities in microsomal preparations of plant tissues. PLANTA 2015; 241:347-58. [PMID: 25298156 PMCID: PMC4302238 DOI: 10.1007/s00425-014-2184-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 09/25/2014] [Indexed: 05/18/2023]
Abstract
Plants have lysophosphatidylcholine transacylase (LPCT) and acyl-CoA:glycerophosphocholine acyltransferase (GPCAT) activities. The combined action of LPCT and GPCAT provides a novel route of PC re-synthesis after its deacylation. Phosphatidylcholine (PC) is the major lipid in eukaryotic membranes and has a central role in overall plant lipid metabolism. It is also the site of production of polyunsaturated fatty acids in plants. The recently discovered acyl-CoA:glycerophosphocholine acyltransferase (GPCAT) activity in yeast provides a novel route of re-synthesising PC via lysophosphatidylcholine (LPC) after its deacylation. This route does not require the degradation of the glycerophosphocholine (GPC) into free choline, the activation of choline to CDP-choline, nor the utilization of CDP-choline by the CDP-choline:diacylglycerol cholinephosphotransferase. We show here that GPCAT activities also are present in membrane preparations from developing oil seeds of safflower and other species as well as in membrane preparations of roots and leaves of Arabidopsis, indicating that GPCAT activity plays a ubiquitous role in plant lipid metabolism. The last step in formation of GPC, the substrate for GPCAT, is the deacylation of LPC. Microsomal membranes of developing safflower seeds utilized LPC in LPC:LPC transacylation reactions (LPCT activities) creating PC and GPC. The results demonstrate that safflower membranes have LPCT and GPCAT activities that represent novel reactions for PC acyl editing. The physiological relevance of these reactions probably has to await identification of the enzymes catalysing these reactions.
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Affiliation(s)
- Ida Lager
- Department of Plant Breeding, Swedish University of Agricultural Sciences, 230 53, Alnarp, Sweden,
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Wang L, Kazachkov M, Shen W, Bai M, Wu H, Zou J. Deciphering the roles of Arabidopsis LPCAT and PAH in phosphatidylcholine homeostasis and pathway coordination for chloroplast lipid synthesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 80:965-76. [PMID: 25268378 DOI: 10.1111/tpj.12683] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Revised: 09/10/2014] [Accepted: 09/22/2014] [Indexed: 05/19/2023]
Abstract
Phosphatidylcholine (PC) is a key intermediate in the metabolic network of glycerolipid biosynthesis. Lysophosphatidylcholine acyltransferase (LPCAT) and phosphatidic acid phosphatase (PAH) are two key enzymes of PC homeostasis. We report that LPCAT activity is markedly induced in the Arabidopsis pah mutant. The quadruple pah lpcat mutant, with dual defects in PAH and LPCAT, had a level of lysophosphatidylcholine (LPC) that was much higher than that in the lpcat mutants and a PC content that was higher than that in the pah mutant. Comparative molecular profile analysis of monogalactosyldiacylglycerol and digalactosyldiacylglycerol revealed that both the pah and pah lpcat mutants had increased proportions of 34:6 from the prokaryotic pathway despite differing levels of LPCAT activity. We show that a decreased representation of the C16:0 C18:2 diacylglycerol moiety in PC was a shared feature of pah and pah lpcat, and that this change in PC metabolic profile correlated with the increased prokaryotic contribution to chloroplast lipid synthesis. We detected increased PC deacylation in the pah lpcat mutant that was attributable at least in part to the induced phospholipases. Increased LPC generation was also evident in the pah mutant, but the phospholipases were not induced, raising the possibility that PC deacylation is mediated by the reverse reaction of LPCAT. We discuss possible roles of LPCAT and PAH in PC turnover that impacts lipid pathway coordination for chloroplast lipid synthesis.
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Affiliation(s)
- Liping Wang
- National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
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Zhou XR, Callahan DL, Shrestha P, Liu Q, Petrie JR, Singh SP. Lipidomic analysis of Arabidopsis seed genetically engineered to contain DHA. FRONTIERS IN PLANT SCIENCE 2014; 5:419. [PMID: 25225497 PMCID: PMC4150447 DOI: 10.3389/fpls.2014.00419] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 08/05/2014] [Indexed: 05/10/2023]
Abstract
Metabolic engineering of omega-3 long-chain (≥C20) polyunsaturated fatty acids (ω3 LC-PUFA) in oilseeds has been one of the key targets in recent years. By expressing a transgenic pathway for enhancing the synthesis of the ω3 LC-PUFA docosahexaenoic acid (DHA) from endogenous α-linolenic acid (ALA), we obtained the production of fish oil-like proportions of DHA in Arabidopsis seed oil. Liquid chromatography-mass spectrometry (LC-MS) was used to characterize the triacylglycerol (TAG), diacylglycerol (DAG) and phospholipid (PL) lipid classes in the transgenic and wild type Arabidopsis seeds at both developing and mature stages. The analysis identified the appearance of several abundant DHA-containing phosphatidylcholine (PC), DAG and TAG molecular species in mature seeds. The relative abundances of PL, DAG, and TAG species showed a preferred combination of LC-PUFA with ALA in the transgenic seeds, where LC-PUFA were esterified in positions usually occupied by 20:1ω9. Trace amounts of di-DHA PC and tri-DHA TAG were identified and confirmed by high resolution MS/MS. Studying the lipidome in transgenic seeds provided insights into where DHA accumulated and combined with other fatty acids of neutral and phospholipids from the developing and mature seeds.
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Affiliation(s)
- Xue-Rong Zhou
- Food Futures National Research Flagship, Commonwealth Scientific and Industrial Research OrganisationCanberra, ACT, Australia
- Plant Industry, Commonwealth Scientific and Industrial Research OrganisationCanberra, ACT, Australia
| | - Damien L. Callahan
- Metabolomics Australia, School of Botany, University of MelbourneMelbourne, VIC, Australia
- Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin UniversityMelbourne, VIC, Australia
| | - Pushkar Shrestha
- Food Futures National Research Flagship, Commonwealth Scientific and Industrial Research OrganisationCanberra, ACT, Australia
| | - Qing Liu
- Food Futures National Research Flagship, Commonwealth Scientific and Industrial Research OrganisationCanberra, ACT, Australia
| | - James R. Petrie
- Food Futures National Research Flagship, Commonwealth Scientific and Industrial Research OrganisationCanberra, ACT, Australia
| | - Surinder P. Singh
- Food Futures National Research Flagship, Commonwealth Scientific and Industrial Research OrganisationCanberra, ACT, Australia
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