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Accelerated triacylglycerol production without growth inhibition by overexpression of a glycerol-3-phosphate acyltransferase in the unicellular red alga Cyanidioschyzon merolae. Sci Rep 2018; 8:12410. [PMID: 30120352 PMCID: PMC6098107 DOI: 10.1038/s41598-018-30809-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 08/04/2018] [Indexed: 12/14/2022] Open
Abstract
Microalgae accumulate triacylglycerols (TAGs), a promising feedstock for biodiesel production, under unfavorable environmental or stress conditions for their growth. Our previous analyses revealed that only transcripts of CmGPAT1 and CmGPAT2, both encoding glycerol-3-phosphate acyltransferase, were increased among fatty acid and TAG synthesis genes under TAG accumulation conditions in the red alga Cyanidioschyzon merolae. In this study, to investigate the role of these proteins in TAG accumulation in C. merolae, we constructed FLAG-fused CmGPAT1 and CmGPAT2 overexpression strains. We found that CmGPAT1 overexpression resulted in marked accumulation of TAG even under normal growth conditions, with the maximum TAG productivity increased 56.1-fold compared with the control strain, without a negative impact on algal growth. The relative fatty acid composition of 18:2 in the TAGs and the sn-1/sn-3 positions were significantly increased compared with the control strain, suggesting that CmGPAT1 had a substrate preference for 18:2. Immunoblot analysis after cell fractionation and immunostaining analysis demonstrated that CmGPAT1 localizes in the endoplasmic reticulum (ER). These results indicate that the reaction catalyzed by the ER-localized CmGPAT1 is a rate-limiting step for TAG synthesis in C. merolae, and would be a potential target for improvement of TAG productivity in microalgae.
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52
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Venkateshwari V, Vijayakumar A, Vijayakumar AK, Reddy LPA, Srinivasan M, Rajasekharan R. Leaf lipidome and transcriptome profiling of Portulaca oleracea: characterization of lysophosphatidylcholine acyltransferase. PLANTA 2018; 248:347-367. [PMID: 29736624 DOI: 10.1007/s00425-018-2908-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 04/16/2018] [Indexed: 06/08/2023]
Abstract
Portulaca leaves serve as an alternative bioresource for edible PUFAs. Transcriptome data provide information to explore Portulaca as a model system for galactolipids, leaf lipid metabolism, and PUFA-rich designer lipids. Poly-unsaturated fatty acids (PUFAs) are gaining importance due to their innumerable health benefits, and hence, understanding their biosynthesis in plants has attained prominence in recent years. The most common source of PUFAs is of marine origin. Although reports have identified Portulaca oleracea (purslane) as a leaf source of omega-3 fatty acids in the form of alpha-linolenic acid (ALA), the mechanism of ALA accumulation and its distribution into various lipids has not been elucidated. Here, we present the lipid profiles of leaves and seeds of several accessions of P. oleracea. Among the nineteen distinct accessions, the RR04 accession has the highest amount of ALA and is primarily associated with galactolipids. In addition, we report the transcriptome of RR04, and we have mapped the potential genes involved in lipid metabolism. Phosphatidylcholine (PC) is the major site of acyl editing, which is catalyzed by lysophosphatidylcholine acyltransferase (LPCAT), an integral membrane protein that plays a major role in supplying oleate to the PC pool for further unsaturation. Our investigations using mass spectrometric analysis of leaf microsomal fractions identified LPCAT as part of a membrane protein complex. Both native and recombinant LPCAT showed strong acyltransferase activity with various acyl-CoA substrates. Altogether, the results suggest that ALA-rich glycerolipid biosynthetic machinery is highly active in nutritionally important Portulaca leaves. Furthermore, lipidome, transcriptome, and mass spectrometric analyses of RR04 provide novel information for exploring Portulaca as a potential resource and a model system for studying leaf lipid metabolism.
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Affiliation(s)
- Varadarajan Venkateshwari
- Department of Lipid Science, Central Food Technological Research Institute, Mysore, 570020, Karnataka, India
- Academy of Scientific and Innovative Research, New Delhi, India
| | - Anitha Vijayakumar
- Department of Lipid Science, Central Food Technological Research Institute, Mysore, 570020, Karnataka, India
| | - Arun Kumar Vijayakumar
- Food Safety and Analytical Quality Control Department, Central Food Technological Research Institute, Mysore, 570020, Karnataka, India
| | - L Prasanna Anjaneya Reddy
- Department of Lipid Science, Central Food Technological Research Institute, Mysore, 570020, Karnataka, India
| | - Malathi Srinivasan
- Department of Lipid Science, Central Food Technological Research Institute, Mysore, 570020, Karnataka, India
- Academy of Scientific and Innovative Research, New Delhi, India
| | - Ram Rajasekharan
- Department of Lipid Science, Central Food Technological Research Institute, Mysore, 570020, Karnataka, India.
- Academy of Scientific and Innovative Research, New Delhi, India.
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53
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Jayawardhane KN, Singer SD, Weselake RJ, Chen G. Plant sn-Glycerol-3-Phosphate Acyltransferases: Biocatalysts Involved in the Biosynthesis of Intracellular and Extracellular Lipids. Lipids 2018; 53:469-480. [PMID: 29989678 DOI: 10.1002/lipd.12049] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 05/15/2018] [Accepted: 05/18/2018] [Indexed: 01/08/2023]
Abstract
Acyl-lipids such as intracellular phospholipids, galactolipids, sphingolipids, and surface lipids play a crucial role in plant cells by serving as major components of cellular membranes, seed storage oils, and extracellular lipids such as cutin and suberin. Plant lipids are also widely used to make food, renewable biomaterials, and fuels. As such, enormous efforts have been made to uncover the specific roles of different genes and enzymes involved in lipid biosynthetic pathways over the last few decades. sn-Glycerol-3-phosphate acyltransferases (GPAT) are a group of important enzymes catalyzing the acylation of sn-glycerol-3-phosphate at the sn-1 or sn-2 position to produce lysophosphatidic acids. This reaction constitutes the first step of storage-lipid assembly and is also important in polar- and extracellular-lipid biosynthesis. Ten GPAT have been identified in Arabidopsis, and many homologs have also been reported in other plant species. These enzymes differentially localize to plastids, mitochondria, and the endoplasmic reticulum, where they have different biological functions, resulting in distinct metabolic fate(s) for lysophosphatidic acid. Although studies in recent years have led to new discoveries about plant GPAT, many gaps still exist in our understanding of this group of enzymes. In this article, we highlight current biochemical and molecular knowledge regarding plant GPAT, and also discuss deficiencies in our understanding of their functions in the context of plant acyl-lipid biosynthesis.
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Affiliation(s)
- Kethmi N Jayawardhane
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 116 St & 85 Ave, Edmonton, Alberta, T6G 2P5, Canada
| | - Stacy D Singer
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, 5403 - 1st Avenue South, Lethbridge, Alberta, T1J 4B1, Canada
| | - Randall J Weselake
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 116 St & 85 Ave, Edmonton, Alberta, T6G 2P5, Canada
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 116 St & 85 Ave, Edmonton, Alberta, T6G 2P5, Canada
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54
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Lu S, Sturtevant D, Aziz M, Jin C, Li Q, Chapman KD, Guo L. Spatial analysis of lipid metabolites and expressed genes reveals tissue-specific heterogeneity of lipid metabolism in high- and low-oil Brassica napus L. seeds. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 94:915-932. [PMID: 29752761 DOI: 10.1111/tpj.13959] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 04/13/2018] [Indexed: 05/20/2023]
Abstract
Despite the importance of oilseeds to worldwide human nutrition, and more recently to the production of bio-based diesel fuels, the detailed mechanisms regulating seed oil biosynthesis remain only partly understood, especially from a tissue-specific perspective. Here, we investigated the spatial distributions of lipid metabolites and transcripts involved in oil biosynthesis from seeds of two low-erucic acid genotypes of Brassica napus with high and low seed-oil content. Integrated results from matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) of lipids in situ, lipidome profiling of extracts from seed tissues, and tissue-specific transcriptome analysis revealed complex spatial distribution patterns of lipids and transcripts. In general, it appeared that many triacylglycerol and phosphatidylcholine species distributed heterogeneously throughout the embryos. Tissue-specific transcriptome analysis identified key genes involved in de novo fatty acid biosynthesis in plastid, triacylglycerols assembly and lipid droplet packaging in the endoplasmic reticulum (ER) that may contribute to the high or low oil phenotype and heterogeneity of lipid distribution. Our results imply that transcriptional regulation represents an important means of impacting lipid compartmentalization in oil seeds. While much information remains to be learned about the intricacies of seed oil accumulation and distribution, these studies highlight the advances that come from evaluating lipid metabolism within a spatial context and with multiple omics level datasets.
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Affiliation(s)
- Shaoping Lu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Drew Sturtevant
- Center for Plant Lipid Research and Department of Biological Sciences, University of North Texas, 1155 Union Circle #305220, Denton, TX, 76203, USA
- BioDiscovery Institute, University of North Texas, 1155 Union Circle #305220, Denton, TX, 76203, USA
| | - Mina Aziz
- Center for Plant Lipid Research and Department of Biological Sciences, University of North Texas, 1155 Union Circle #305220, Denton, TX, 76203, USA
- BioDiscovery Institute, University of North Texas, 1155 Union Circle #305220, Denton, TX, 76203, USA
| | - Cheng Jin
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Qing Li
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Kent D Chapman
- Center for Plant Lipid Research and Department of Biological Sciences, University of North Texas, 1155 Union Circle #305220, Denton, TX, 76203, USA
- BioDiscovery Institute, University of North Texas, 1155 Union Circle #305220, Denton, TX, 76203, USA
| | - Liang Guo
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
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55
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Lei J, Miao Y, Lan Y, Han X, Liu H, Gan Y, Niu L, Wang Y, Zheng Z. A Novel Complementation Assay for Quick and Specific Screen of Genes Encoding Glycerol-3-Phosphate Acyltransferases. FRONTIERS IN PLANT SCIENCE 2018; 9:353. [PMID: 29616064 PMCID: PMC5867339 DOI: 10.3389/fpls.2018.00353] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 03/02/2018] [Indexed: 06/08/2023]
Abstract
The initial step in glycerolipid biosynthesis, especially in diverse allopolyploid crop species, is poorly understood, mainly due to the lack of an effective and convenient method for functional characterization of genes encoding glycerol-3-phosphate acyltransferases (GPATs) catalyzing this reaction. Here we present a novel complementation assay for quick and specific characterization of GPAT-encoding genes. Its key design involves rational construction of yeast conditional lethal gat1Δgat2Δ double mutant bearing the heterologous Arabidopsis AtGPAT1 gene whose leaky expression under repressed conditions does not support any non-specific growth, thereby circumventing the false positive problem encountered with the system based on the gat1Δgat2Δ mutant harboring the native episomal GAT1 gene whose leaky expression appears to be sufficient for generating enough GPAT activities for the non-specific restoration of the mutant growth. A complementation assay developed based on this novel mutant enables quick phenotypic screen of GPAT sequences. A high degree of specificity of our assay was exemplified by its ability to differentiate effectively GPAT-encoding genes from those of other fatty acyltransferases and lipid-related sequences. Using this assay, we show that Arabidopsis AtGPAT1, AtGPAT5, and AtGPAT7 can complement the phosphatidate biosynthetic defect in the double mutants. Collectively, our assay provides a powerful tool for rapid screening, validation and optimization of GPAT sequences, aiding future engineering of the initial step of the triacylglycerol biosynthesis in oilseeds.
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Affiliation(s)
- Jie Lei
- School of Agriculture and Food Science, Zhejiang A & F University, Hangzhou, China
| | - Yingchun Miao
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou, China
| | - Yu Lan
- School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou, China
| | - Xiuxiu Han
- School of Agriculture and Food Science, Zhejiang A & F University, Hangzhou, China
| | - Hongbo Liu
- School of Agriculture and Food Science, Zhejiang A & F University, Hangzhou, China
| | - Yi Gan
- School of Agriculture and Food Science, Zhejiang A & F University, Hangzhou, China
| | - Leilei Niu
- School of Agriculture and Food Science, Zhejiang A & F University, Hangzhou, China
| | - Yanyan Wang
- School of Agriculture and Food Science, Zhejiang A & F University, Hangzhou, China
| | - Zhifu Zheng
- School of Agriculture and Food Science, Zhejiang A & F University, Hangzhou, China
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56
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Waschburger E, Kulcheski FR, Veto NM, Margis R, Margis-Pinheiro M, Turchetto-Zolet AC. Genome-wide analysis of the Glycerol-3-Phosphate Acyltransferase (GPAT) gene family reveals the evolution and diversification of plant GPATs. Genet Mol Biol 2018; 41:355-370. [PMID: 29583156 PMCID: PMC5913721 DOI: 10.1590/1678-4685-gmb-2017-0076] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 08/01/2017] [Indexed: 01/05/2023] Open
Abstract
sn-Glycerol-3-phosphate 1-O-acyltransferase (GPAT) is an important enzyme that catalyzes the transfer of an acyl group from acyl-CoA or acyl-ACP to the sn-1 or sn-2 position of sn-glycerol-3-phosphate (G3P) to generate lysophosphatidic acids (LPAs). The functional studies of GPAT in plants demonstrated its importance in controlling storage and membrane lipid. Identifying genes encoding GPAT in a variety of plant species is crucial to understand their involvement in different metabolic pathways and physiological functions. Here, we performed genome-wide and evolutionary analyses of GPATs in plants. GPAT genes were identified in all algae and plants studied. The phylogenetic analysis showed that these genes group into three main clades. While clades I (GPAT9) and II (soluble GPAT) include GPATs from algae and plants, clade III (GPAT1-8) includes GPATs specific from plants that are involved in the biosynthesis of cutin or suberin. Gene organization and the expression pattern of GPATs in plants corroborate with clade formation in the phylogeny, suggesting that the evolutionary patterns is reflected in their functionality. Overall, our results provide important insights into the evolution of the plant GPATs and allowed us to explore the evolutionary mechanism underlying the functional diversification among these genes.
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Affiliation(s)
- Edgar Waschburger
- Graduação em Biotecnologia, Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Franceli Rodrigues Kulcheski
- Departamento de Biologia Celular, Embriologia e Genética, Universidade Federal de Santa Catarina (UFSC), Florianópolis, SC, Brazil
| | - Nicole Moreira Veto
- Programa de Pós-Graduação em Genética e Biologia Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Rogerio Margis
- Programa de Pós-Graduação em Genética e Biologia Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.,Centro de Biotecnologia e Programa de Pós-Graduação em Biologia Celular e Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.,Departamento de Biofísica, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Marcia Margis-Pinheiro
- Programa de Pós-Graduação em Genética e Biologia Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Andreia Carina Turchetto-Zolet
- Programa de Pós-Graduação em Genética e Biologia Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
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57
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Singer SD, Weselake RJ, Acharya S. Molecular Enhancement of Alfalfa: Improving Quality Traits for Superior Livestock Performance and Reduced Environmental Impact. CROP SCIENCE 2018; 58:55-71. [PMID: 0 DOI: 10.2135/cropsci2017.07.0434] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Affiliation(s)
- Stacy D. Singer
- Agriculture and Agri-Food Canada; Lethbridge Research and Development Centre; Lethbridge AB Canada T1J 4B1
| | - Randall J. Weselake
- Dep. of Agricultural, Food and Nutritional Science; Univ. of Alberta; Edmonton AB Canada T6G 2P5
| | - Surya Acharya
- Agriculture and Agri-Food Canada; Lethbridge Research and Development Centre; Lethbridge AB Canada T1J 4B1
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58
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Nakamura Y. Plant Phospholipid Diversity: Emerging Functions in Metabolism and Protein-Lipid Interactions. TRENDS IN PLANT SCIENCE 2017; 22:1027-1040. [PMID: 28993119 DOI: 10.1016/j.tplants.2017.09.002] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 08/26/2017] [Accepted: 09/07/2017] [Indexed: 05/22/2023]
Abstract
Phospholipids are essential components of biological membranes and signal transduction cascades in plants. In recent years, plant phospholipid research was greatly advanced by the characterization of numerous mutants affected in phospholipid biosynthesis and the discovery of a number of functionally important phospholipid-binding proteins. It is now accepted that most phospholipids to some extent have regulatory functions, including those that serve as constituents of biological membranes. Phospholipids are more than an inert end product of lipid biosynthesis. This review article summarizes recent advances on phospholipid biosynthesis with a particular focus on polar head group synthesis, followed by a short overview on protein-phospholipid interactions as an emerging regulatory mechanism of phospholipid function in arabidopsis (Arabidopsis thaliana).
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Affiliation(s)
- Yuki Nakamura
- Institute of Plant and Microbial Biology, Academia Sinica, Taiwan 11529, Taiwan; http://ipmb.sinica.edu.tw/index.html/?q=node/972&language=en.
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59
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Reynolds KB, Taylor MC, Cullerne DP, Blanchard CL, Wood CC, Singh SP, Petrie JR. A reconfigured Kennedy pathway which promotes efficient accumulation of medium-chain fatty acids in leaf oils. PLANT BIOTECHNOLOGY JOURNAL 2017; 15:1397-1408. [PMID: 28301719 PMCID: PMC5633779 DOI: 10.1111/pbi.12724] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 02/12/2017] [Accepted: 03/10/2017] [Indexed: 05/23/2023]
Abstract
Medium-chain fatty acids (MCFA, C6-14 fatty acids) are an ideal feedstock for biodiesel and broader oleochemicals. In recent decades, several studies have used transgenic engineering to produce MCFA in seeds oils, although these modifications result in unbalance membrane lipid profiles that impair oil yields and agronomic performance. Given the ability to engineer nonseed organs to produce oils, we have previously demonstrated that MCFA profiles can be produced in leaves, but this also results in unbalanced membrane lipid profiles and undesirable chlorosis and cell death. Here we demonstrate that the introduction of a diacylglycerol acyltransferase from oil palm, EgDGAT1, was necessary to channel nascent MCFA directly into leaf oils and therefore bypassing MCFA residing in membrane lipids. This pathway resulted in increased flux towards MCFA rich leaf oils, reduced MCFA in leaf membrane lipids and, crucially, the alleviation of chlorosis. Deep sequencing of African oil palm (Elaeis guineensis) and coconut palm (Cocos nucifera) generated candidate genes of interest, which were then tested for their ability to improve oil accumulation. Thioesterases were explored for the production of lauric acid (C12:0) and myristic (C14:0). The thioesterases from Umbellularia californica and Cinnamomum camphora produced a total of 52% C12:0 and 40% C14:0, respectively, in transient leaf assays. This study demonstrated that the introduction of a complete acyl-CoA-dependent pathway for the synthesis of MFCA-rich oils avoided disturbing membrane homoeostasis and cell death phenotypes. This study outlines a transgenic strategy for the engineering of biomass crops with high levels of MCFA rich leaf oils.
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Affiliation(s)
- Kyle B. Reynolds
- Commonwealth Scientific and Industrial Research Organization, Agriculture and FoodActonACTAustralia
- Department of Primary IndustriesGraham Centre for Agricultural InnovationCharles Sturt UniversityWagga WaggaNSWAustralia
- ARC Industrial Transformation Training Centre for Functional GrainsCharles Sturt UniversityWagga WaggaNSWAustralia
| | - Matthew C. Taylor
- Commonwealth Scientific and Industrial Research OrganizationLand and WaterActonACTAustralia
| | - Darren P. Cullerne
- Commonwealth Scientific and Industrial Research Organization, Agriculture and FoodActonACTAustralia
- School of Environmental and Life SciencesUniversity of NewcastleNewcastleNSWAustralia
| | - Christopher L. Blanchard
- ARC Industrial Transformation Training Centre for Functional GrainsCharles Sturt UniversityWagga WaggaNSWAustralia
| | - Craig C. Wood
- Commonwealth Scientific and Industrial Research Organization, Agriculture and FoodActonACTAustralia
| | - Surinder P. Singh
- Commonwealth Scientific and Industrial Research Organization, Agriculture and FoodActonACTAustralia
| | - James R. Petrie
- Commonwealth Scientific and Industrial Research Organization, Agriculture and FoodActonACTAustralia
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60
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Misra A, Khan K, Niranjan A, Kumar V, Sane VA. Heterologous expression of two GPATs from Jatropha curcas alters seed oil levels in transgenic Arabidopsis thaliana. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2017; 263:79-88. [PMID: 28818386 DOI: 10.1016/j.plantsci.2017.07.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 07/07/2017] [Indexed: 06/07/2023]
Abstract
Oils and fats are stored in endosperm during seed development in the form of triacylglycerols. Three acyltransferases: glycerol-3-phosphate acyltransferase (GPAT), lysophosphatidyl acyltransferase (LPAT) and diacylglycerol acyltransferase (DGAT) are involved in the storage lipid biosynthesis and catalyze the stepwise acylation of glycerol backbone. In this study two members of GPAT gene family (JcGPAT1 and JcGPAT2) from Jatropha seeds were identified and characterized. Sequence analysis suggested that JcGPAT1 and JcGPAT2 are homologous to Arabidopsis acyltransferase-1 (ATS1) and AtGPAT9 respectively. The sub-cellular localization studies of these two GPATs showed that JcGPAT1 localizes into plastid whereas JcGPAT2 localizes in to endoplasmic reticulum. JcGPAT1 and JcGPAT2 expressed throughout the seed development with higher expression in fully matured seed compared to immature seed. The transcript levels of JcGPAT2 were higher in comparison to JcGPAT1 in different developmental stages of seed. Over-expression of JcGPAT1 and JcGPAT2 under constitutive and seed specific promoters in Arabidopsis thaliana increased total oil content. Transgenic seeds of JcGPAT2-OE lines accumulated 43-60% more oil than control seeds whereas seeds of Arabidopsis lines over-expressing plastidial GPAT lead to only 13-20% increase in oil content. Functional characterization of GPAT homologues of Jatropha in Arabidopsis suggested that these are involved in oil biosynthesis but might have specific roles in Jatropha.
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Affiliation(s)
- Aparna Misra
- Plant Gene Expression Lab, CSIR-National Botanical Research Institute, Lucknow-226001, India
| | - Kasim Khan
- Plant Gene Expression Lab, CSIR-National Botanical Research Institute, Lucknow-226001, India
| | - Abhishek Niranjan
- Plant Gene Expression Lab, CSIR-National Botanical Research Institute, Lucknow-226001, India
| | - Vinod Kumar
- Plant Gene Expression Lab, CSIR-National Botanical Research Institute, Lucknow-226001, India
| | - Vidhu A Sane
- Plant Gene Expression Lab, CSIR-National Botanical Research Institute, Lucknow-226001, India.
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61
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Yurchenko O, Shockey JM, Gidda SK, Silver MI, Chapman KD, Mullen RT, Dyer JM. Engineering the production of conjugated fatty acids in Arabidopsis thaliana leaves. PLANT BIOTECHNOLOGY JOURNAL 2017; 15:1010-1023. [PMID: 28083898 PMCID: PMC5506653 DOI: 10.1111/pbi.12695] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 12/28/2016] [Accepted: 01/05/2017] [Indexed: 05/23/2023]
Abstract
The seeds of many nondomesticated plant species synthesize oils containing high amounts of a single unusual fatty acid, many of which have potential usage in industry. Despite the identification of enzymes for unusual oxidized fatty acid synthesis, the production of these fatty acids in engineered seeds remains low and is often hampered by their inefficient exclusion from phospholipids. Recent studies have established the feasibility of increasing triacylglycerol content in plant leaves, which provides a novel approach for increasing energy density of biomass crops. Here, we determined whether the fatty acid composition of leaf oil could be engineered to accumulate unusual fatty acids. Eleostearic acid (ESA) is a conjugated fatty acid produced in seeds of the tung tree (Vernicia fordii) and has both industrial and nutritional end-uses. Arabidopsis thaliana lines with elevated leaf oil were first generated by transforming wild-type, cgi-58 or pxa1 mutants (the latter two of which contain mutations disrupting fatty acid breakdown) with the diacylglycerol acyltransferases (DGAT1 or DGAT2) and/or oleosin genes from tung. High-leaf-oil plant lines were then transformed with tung FADX, which encodes the fatty acid desaturase/conjugase responsible for ESA synthesis. Analysis of lipids in leaves revealed that ESA was efficiently excluded from phospholipids, and co-expression of tung FADX and DGAT2 promoted a synergistic increase in leaf oil content and ESA accumulation. Taken together, these results provide a new approach for increasing leaf oil content that is coupled with accumulation of unusual fatty acids. Implications for production of biofuels, bioproducts, and plant-pest interactions are discussed.
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Affiliation(s)
- Olga Yurchenko
- USDA‐ARSUS Arid‐Land Agricultural Research CenterMaricopaAZUSA
| | - Jay M. Shockey
- USDA‐ARSSouthern Regional Research CenterNew OrleansLAUSA
| | - Satinder K. Gidda
- Department of Molecular and Cellular BiologyUniversity of GuelphGuelphONCanada
| | - Maxwell I. Silver
- Department of Molecular and Cellular BiologyUniversity of GuelphGuelphONCanada
| | - Kent D. Chapman
- Department of Biological SciencesUniversity of North TexasDentonTXUSA
| | - Robert T. Mullen
- Department of Molecular and Cellular BiologyUniversity of GuelphGuelphONCanada
| | - John M. Dyer
- USDA‐ARSUS Arid‐Land Agricultural Research CenterMaricopaAZUSA
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62
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Garibay-Hernández A, Barkla BJ, Vera-Estrella R, Martinez A, Pantoja O. Membrane Proteomic Insights into the Physiology and Taxonomy of an Oleaginous Green Microalga. PLANT PHYSIOLOGY 2017; 173:390-416. [PMID: 27837088 PMCID: PMC5210721 DOI: 10.1104/pp.16.01240] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 11/03/2016] [Indexed: 05/22/2023]
Abstract
Ettlia oleoabundans is a nonsequenced oleaginous green microalga. Despite the significant biotechnological interest in producing value-added compounds from the acyl lipids of this microalga, a basic understanding of the physiology and biochemistry of oleaginous microalgae is lacking, especially under nitrogen deprivation conditions known to trigger lipid accumulation. Using an RNA sequencing-based proteomics approach together with manual annotation, we are able to provide, to our knowledge, the first membrane proteome of an oleaginous microalga. This approach allowed the identification of novel proteins in E. oleoabundans, including two photoprotection-related proteins, Photosystem II Subunit S and Maintenance of Photosystem II under High Light1, which were considered exclusive to higher photosynthetic organisms, as well as Retinitis Pigmentosa Type 2-Clathrin Light Chain, a membrane protein with a novel domain architecture. Free-flow zonal electrophoresis of microalgal membranes coupled to liquid chromatography-tandem mass spectrometry proved to be a useful technique for determining the intracellular location of proteins of interest. Carbon-flow compartmentalization in E. oleoabundans was modeled using this information. Molecular phylogenetic analyses of protein markers and 18S ribosomal DNA support the reclassification of E. oleoabundans within the trebouxiophycean microalgae, rather than with the Chlorophyceae class, in which it is currently classified, indicating that it may not be closely related to the model green alga Chlamydomonas reinhardtii A detailed survey of biological processes taking place in the membranes of nitrogen-deprived E. oleoabundans, including lipid metabolism, provides insights into the basic biology of this nonmodel organism.
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Affiliation(s)
- Adriana Garibay-Hernández
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210 Mexico (A.G.-H., R.V.-E., A.M., O.P.); and
- Southern Cross Plant Science, Southern Cross University, Lismore, 2480 New South Wales, Australia (B.J.B.)
| | - Bronwyn J Barkla
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210 Mexico (A.G.-H., R.V.-E., A.M., O.P.); and
- Southern Cross Plant Science, Southern Cross University, Lismore, 2480 New South Wales, Australia (B.J.B.)
| | - Rosario Vera-Estrella
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210 Mexico (A.G.-H., R.V.-E., A.M., O.P.); and
- Southern Cross Plant Science, Southern Cross University, Lismore, 2480 New South Wales, Australia (B.J.B.)
| | - Alfredo Martinez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210 Mexico (A.G.-H., R.V.-E., A.M., O.P.); and
- Southern Cross Plant Science, Southern Cross University, Lismore, 2480 New South Wales, Australia (B.J.B.)
| | - Omar Pantoja
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210 Mexico (A.G.-H., R.V.-E., A.M., O.P.); and
- Southern Cross Plant Science, Southern Cross University, Lismore, 2480 New South Wales, Australia (B.J.B.)
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Botella C, Jouhet J, Block MA. Importance of phosphatidylcholine on the chloroplast surface. Prog Lipid Res 2017; 65:12-23. [DOI: 10.1016/j.plipres.2016.11.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 11/04/2016] [Accepted: 11/06/2016] [Indexed: 12/11/2022]
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Meï CE, Cussac M, Haslam RP, Beaudoin F, Wong YS, Maréchal E, Rébeillé F. C1 Metabolism Inhibition and Nitrogen Deprivation Trigger Triacylglycerol Accumulation in Arabidopsis thaliana Cell Cultures and Highlight a Role of NPC in Phosphatidylcholine-to-Triacylglycerol Pathway. FRONTIERS IN PLANT SCIENCE 2016; 7:2014. [PMID: 28101097 PMCID: PMC5209388 DOI: 10.3389/fpls.2016.02014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 12/19/2016] [Indexed: 05/20/2023]
Abstract
Triacylglycerol (TAG) accumulation often occurs in growth limiting conditions such as nutrient deprivations. We analyzed and compared the lipid contents of Arabidopsis cells grown under two conditions that inhibited growth as a way to study interactions between membrane and storage lipids. In order to inhibit C1 metabolism, the first condition utilized methotrexate (MTX), a drug that inhibits methyl transfer reactions and potentially reduces Pi-choline synthesis, the polar head of phosphatidylcholine (PC). MTX-treated cells displayed a 10- to 15-fold increase in TAG compared to that found in control cells. This corresponded to a net increase of lipids as the total amount of membrane glycerolipids was minimally affected. Under this condition, PC homeostasis appeared tightly regulated and not strictly dependent on the rate of Pi-choline synthesis. The second condition we investigated involved nitrogen deprivation. Here, we observed a 40-fold increase of TAG. In these cells, the overall lipid content remained unchanged, but membrane lipids decreased by a factor of two suggesting a reduction of the membrane network and a rerouting of membrane lipids to storage lipids. Under all conditions, fatty acid (FA) analyses showed that the FA composition of TAG was comparable to that in PC, but different from that in acyl-CoA, suggesting that TAG accumulation involved PC-derived DAG moieties. In agreement, analyses by qPCR of genes coding for TAG synthesis showed a strong increase of non-specific phospholipase C (NPC) expressions, and experiments using labeled (fluorescent) PC indicated higher rates of PC-to-TAG conversion under both situations. These results highlight a role for NPC in plant cell oil production.
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Affiliation(s)
- Coline E. Meï
- Laboratoire de Physiologie Cellulaire Végétale, UMR 5168 CNRS – CEA – INRA – Université Grenoble Alpes, Bioscience and Biotechnologies Institute of GrenobleCEA-Grenoble, Grenoble, France
| | - Mathilde Cussac
- Laboratoire de Physiologie Cellulaire Végétale, UMR 5168 CNRS – CEA – INRA – Université Grenoble Alpes, Bioscience and Biotechnologies Institute of GrenobleCEA-Grenoble, Grenoble, France
| | - Richard P. Haslam
- Department of Biological Chemistry and Crop Protection, Rothamsted ResearchHarpenden, UK
| | - Frédéric Beaudoin
- Department of Biological Chemistry and Crop Protection, Rothamsted ResearchHarpenden, UK
| | - Yung-Sing Wong
- Département de Pharmacochimie Moléculaire, UMR 5063 CNRS – Université Grenoble AlpesGrenoble, France
| | - Eric Maréchal
- Laboratoire de Physiologie Cellulaire Végétale, UMR 5168 CNRS – CEA – INRA – Université Grenoble Alpes, Bioscience and Biotechnologies Institute of GrenobleCEA-Grenoble, Grenoble, France
| | - Fabrice Rébeillé
- Laboratoire de Physiologie Cellulaire Végétale, UMR 5168 CNRS – CEA – INRA – Université Grenoble Alpes, Bioscience and Biotechnologies Institute of GrenobleCEA-Grenoble, Grenoble, France
- *Correspondence: Fabrice Rébeillé,
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