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Luo N, Wang Y, Liu Y, Wang Y, Guo Y, Chen C, Gan Q, Song Y, Fan Y, Jin S, Ni Y. 3-ketoacyl-CoA synthase 19 contributes to the biosynthesis of seed lipids and cuticular wax in Arabidopsis and abiotic stress tolerance. PLANT, CELL & ENVIRONMENT 2024. [PMID: 39041727 DOI: 10.1111/pce.15054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 06/26/2024] [Accepted: 07/08/2024] [Indexed: 07/24/2024]
Abstract
Very-long-chain fatty acids (VLCFAs) are essential precursors for plant membrane lipids, cuticular waxes, suberin, and storage oils. Integral to the fatty acid elongase (FAE) complex, 3-ketoacyl-CoA synthases (KCSs) function as crucial enzymes in the VLCFA pathway, determining the chain length of VLCFA. This study explores the in-planta role of the KCS19 gene. KCS19 is predominantly expressed in leaves and stem epidermis, sepals, styles, early silique walls, beaks, pedicels, and mature embryos. Localized in the endoplasmic reticulum, KCS19 interacts with other FAE proteins. kcs19 knockout mutants displayed reduced total wax and wax crystals, particularly alkanes, while KCS19 overexpression increased these components and wax crystals. Moreover, the cuticle permeability was higher for the kcs19 mutants compared to the wild type, rendering them more susceptible to drought and salt stress, whereas KCS19 overexpression enhanced drought and salt tolerance. Disrupting KCS19 increased C18 species and decreased C20 and longer species in seed fatty acids, indicating its role in elongating C18 to C20 VLCFAs, potentially up to C24 for seed storage lipids. Collectively, KCS19-mediated VLCFA synthesis is required for cuticular wax biosynthesis and seed storage lipids, impacting plant responses to abiotic stress.
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Affiliation(s)
- Na Luo
- College of Agronomy, Qingdao Agricultural University, Qingdao, China
- Qingdao Key Laboratory of Specialty Plant Germplasm Innovation and Utilization in Saline Soils of Coastal Beach, Qingdao Agricultural University, Qingdao, China
- College of Agronomy and Biotechnology, Southwest University, Chongqing, China
- Dongying Key Laboratory of Germplasm Resources Identification and Application of Oil Crops in Saline alkali Land, Academy of Dongying Efficient Agricultural Technology and Industry on Saline and Alkaline Land in Collaboration with Qingdao Agricultural University, Dongying, China
| | - Yulu Wang
- College of Agronomy and Biotechnology, Southwest University, Chongqing, China
| | - Yu Liu
- College of Agronomy, Qingdao Agricultural University, Qingdao, China
- College of Agronomy and Biotechnology, Southwest University, Chongqing, China
- Dongying Key Laboratory of Germplasm Resources Identification and Application of Oil Crops in Saline alkali Land, Academy of Dongying Efficient Agricultural Technology and Industry on Saline and Alkaline Land in Collaboration with Qingdao Agricultural University, Dongying, China
| | - Yuxin Wang
- College of Agronomy, Qingdao Agricultural University, Qingdao, China
- College of Agronomy and Biotechnology, Southwest University, Chongqing, China
- Dongying Key Laboratory of Germplasm Resources Identification and Application of Oil Crops in Saline alkali Land, Academy of Dongying Efficient Agricultural Technology and Industry on Saline and Alkaline Land in Collaboration with Qingdao Agricultural University, Dongying, China
| | - Yanjun Guo
- Qingdao Key Laboratory of Specialty Plant Germplasm Innovation and Utilization in Saline Soils of Coastal Beach, Qingdao Agricultural University, Qingdao, China
- College of Grassland Science, Qingdao Agricultural University, Qingdao, China
| | - Chunjie Chen
- College of Agronomy, Qingdao Agricultural University, Qingdao, China
- College of Agronomy and Biotechnology, Southwest University, Chongqing, China
- Dongying Key Laboratory of Germplasm Resources Identification and Application of Oil Crops in Saline alkali Land, Academy of Dongying Efficient Agricultural Technology and Industry on Saline and Alkaline Land in Collaboration with Qingdao Agricultural University, Dongying, China
| | - Qiaoqiao Gan
- College of Agronomy, Qingdao Agricultural University, Qingdao, China
- College of Agronomy and Biotechnology, Southwest University, Chongqing, China
- Dongying Key Laboratory of Germplasm Resources Identification and Application of Oil Crops in Saline alkali Land, Academy of Dongying Efficient Agricultural Technology and Industry on Saline and Alkaline Land in Collaboration with Qingdao Agricultural University, Dongying, China
| | - Yuyang Song
- College of Agronomy, Qingdao Agricultural University, Qingdao, China
- Qingdao Key Laboratory of Specialty Plant Germplasm Innovation and Utilization in Saline Soils of Coastal Beach, Qingdao Agricultural University, Qingdao, China
- Dongying Key Laboratory of Germplasm Resources Identification and Application of Oil Crops in Saline alkali Land, Academy of Dongying Efficient Agricultural Technology and Industry on Saline and Alkaline Land in Collaboration with Qingdao Agricultural University, Dongying, China
| | - Yongxin Fan
- College of Agronomy, Qingdao Agricultural University, Qingdao, China
- Qingdao Key Laboratory of Specialty Plant Germplasm Innovation and Utilization in Saline Soils of Coastal Beach, Qingdao Agricultural University, Qingdao, China
- Dongying Key Laboratory of Germplasm Resources Identification and Application of Oil Crops in Saline alkali Land, Academy of Dongying Efficient Agricultural Technology and Industry on Saline and Alkaline Land in Collaboration with Qingdao Agricultural University, Dongying, China
| | - Shurong Jin
- College of Agronomy and Biotechnology, Southwest University, Chongqing, China
| | - Yu Ni
- College of Agronomy, Qingdao Agricultural University, Qingdao, China
- College of Agronomy and Biotechnology, Southwest University, Chongqing, China
- Dongying Key Laboratory of Germplasm Resources Identification and Application of Oil Crops in Saline alkali Land, Academy of Dongying Efficient Agricultural Technology and Industry on Saline and Alkaline Land in Collaboration with Qingdao Agricultural University, Dongying, China
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Kim SC, Edgeworth KN, Nusinow DA, Wang X. Circadian clock factors regulate the first condensation reaction of fatty acid synthesis in Arabidopsis. Cell Rep 2023; 42:113483. [PMID: 37995186 PMCID: PMC10842715 DOI: 10.1016/j.celrep.2023.113483] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 09/16/2023] [Accepted: 11/07/2023] [Indexed: 11/25/2023] Open
Abstract
The circadian clock regulates temporal metabolic activities, but how it affects lipid metabolism is poorly understood. Here, we show that the central clock regulators LATE ELONGATED HYPOCOTYL (LHY) and CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) regulate the initial step of fatty acid (FA) biosynthesis in Arabidopsis. Triacylglycerol (TAG) accumulation in seeds was increased in LHY-overexpressing (LHY-OE) and decreased in lhycca1 plants. Metabolic tracking of lipids in developing seeds indicated that LHY enhanced FA synthesis. Transcript analysis revealed that the expression of genes involved in FA synthesis, including the one encoding β-ketoacyl-ACP synthase III (KASIII), was oppositely changed in developing seeds of LHY/CCA1-OEs and lhycca1. Chromatin immunoprecipitation, electrophoretic mobility shift, and transactivation assays indicated that LHY bound and activated the promoter of KASIII. Furthermore, phosphatidic acid, a metabolic precursor to TAG, inhibited LHY binding to KASIII promoter elements. Our data show a regulatory mechanism for plant lipid biosynthesis by the molecular clock.
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Affiliation(s)
- Sang-Chul Kim
- Department of Biology, University of Missouri-St. Louis, St. Louis, MO 63121, USA; Donald Danforth Plant Science Center, St. Louis, MO 63132, USA
| | - Kristen N Edgeworth
- Donald Danforth Plant Science Center, St. Louis, MO 63132, USA; Department of Biological and Biomedical Sciences, Washington University in St. Louis, St. Louis, MO 63130, USA
| | | | - Xuemin Wang
- Department of Biology, University of Missouri-St. Louis, St. Louis, MO 63121, USA; Donald Danforth Plant Science Center, St. Louis, MO 63132, USA.
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3
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Yang Y, Kong Q, Lim ARQ, Lu S, Zhao H, Guo L, Yuan L, Ma W. Transcriptional regulation of oil biosynthesis in seed plants: Current understanding, applications, and perspectives. PLANT COMMUNICATIONS 2022; 3:100328. [PMID: 35605194 PMCID: PMC9482985 DOI: 10.1016/j.xplc.2022.100328] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 02/28/2022] [Accepted: 04/14/2022] [Indexed: 05/11/2023]
Abstract
Plants produce and accumulate triacylglycerol (TAG) in their seeds as an energy reservoir to support the processes of seed germination and seedling development. Plant seed oils are vital not only for the human diet but also as renewable feedstocks for industrial use. TAG biosynthesis consists of two major steps: de novo fatty acid biosynthesis in the plastids and TAG assembly in the endoplasmic reticulum. The latest advances in unraveling transcriptional regulation have shed light on the molecular mechanisms of plant oil biosynthesis. We summarize recent progress in understanding the regulatory mechanisms of well-characterized and newly discovered transcription factors and other types of regulators that control plant fatty acid biosynthesis. The emerging picture shows that plant oil biosynthesis responds to developmental and environmental cues that stimulate a network of interacting transcriptional activators and repressors, which in turn fine-tune the spatiotemporal regulation of the pathway genes.
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Affiliation(s)
- Yuzhou Yang
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Que Kong
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Audrey R Q Lim
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Shaoping Lu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Hu Zhao
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Liang Guo
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; Hubei Hongshan Laboratory, Wuhan 430070, China.
| | - Ling Yuan
- Department of Plant and Soil Sciences, Kentucky Tobacco Research and Development Center, University of Kentucky, Lexington, KY 40546, USA; Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
| | - Wei Ma
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.
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4
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Bhandari S, Bates PD. Triacylglycerol remodeling in Physaria fendleri indicates oil accumulation is dynamic and not a metabolic endpoint. PLANT PHYSIOLOGY 2021; 187:799-815. [PMID: 34608961 PMCID: PMC8491037 DOI: 10.1093/plphys/kiab294] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 06/05/2021] [Indexed: 05/26/2023]
Abstract
Oilseed plants accumulate triacylglycerol (TAG) up to 80% of seed weight with the TAG fatty acid composition determining its nutritional value or use in the biofuel or chemical industries. Two major pathways for production of diacylglycerol (DAG), the immediate precursor to TAG, have been identified in plants: de novo DAG synthesis and conversion of the membrane lipid phosphatidylcholine (PC) to DAG, with each pathway producing distinct TAG compositions. However, neither pathway fits with previous biochemical and transcriptomic results from developing Physaria fendleri seeds for accumulation of TAG containing >60% lesquerolic acid (an unusual 20 carbon hydroxylated fatty acid), which accumulates at only the sn-1 and sn-3 positions of TAG. Isotopic tracing of developing P. fendleri seed lipid metabolism identified that PC-derived DAG is utilized to initially produce TAG with only one lesquerolic acid. Subsequently a nonhydroxylated fatty acid is removed from TAG (transiently reproducing DAG) and a second lesquerolic acid is incorporated. Thus, a dynamic TAG remodeling process involving anabolic and catabolic reactions controls the final TAG fatty acid composition. Reinterpretation of P. fendleri transcriptomic data identified potential genes involved in TAG remodeling that could provide a new approach for oilseed engineering by altering oil fatty acid composition after initial TAG synthesis; and the comparison of current results to that of related Brassicaceae species in the literature suggests the possibility of TAG remodeling involved in incorporation of very long-chain fatty acids into the TAG sn-1 position in various plants.
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Affiliation(s)
- Sajina Bhandari
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164, USA
| | - Philip D. Bates
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164, USA
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5
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Kotapati HK, Bates PD. 14C-Tracing of Lipid Metabolism. Methods Mol Biol 2021; 2295:59-80. [PMID: 34047972 DOI: 10.1007/978-1-0716-1362-7_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Lipids are produced through a dynamic metabolic network involving branch points, cycles, reversible reactions, parallel reactions in different subcellular compartments, and distinct pools of the same lipid class involved in different parts of the network. For example, diacylglycerol (DAG) is a biosynthetic and catabolic intermediate of many different lipid classes. Triacylglycerol can be synthesized from DAG assembled de novo, or from DAG produced by catabolism of membrane lipids, most commonly phosphatidylcholine. Quantification of lipids provides a snapshot of the lipid abundance at the time they were extracted from the given tissue. However, quantification alone does not provide information on the path of carbon flux through the metabolic network to synthesize each lipid. Understanding lipid metabolic flux requires tracing lipid metabolism with isotopically labeled substrates over time in living tissue. [14C]acetate and [14C]glycerol are commonly utilized substrates to measure the flux of nascent fatty acids and glycerol backbones through the lipid metabolic network in vivo. When combined with mutant or transgenic plants, tracing of lipid metabolism can provide information on the molecular control of lipid metabolic flux. This chapter provides a method for tracing in vivo lipid metabolism in developing Arabidopsis thaliana seeds, including analysis of 14C labeled lipid classes and fatty acid regiochemistry through both thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) approaches.
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Affiliation(s)
- Hari Kiran Kotapati
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Philip D Bates
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA.
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6
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Han L, Usher S, Sandgrind S, Hassall K, Sayanova O, Michaelson LV, Haslam RP, Napier JA. High level accumulation of EPA and DHA in field-grown transgenic Camelina - a multi-territory evaluation of TAG accumulation and heterogeneity. PLANT BIOTECHNOLOGY JOURNAL 2020; 18:2280-2291. [PMID: 32304615 PMCID: PMC7589388 DOI: 10.1111/pbi.13385] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 03/17/2020] [Accepted: 04/07/2020] [Indexed: 05/06/2023]
Abstract
The transgene-directed accumulation of non-native omega-3 long chain polyunsaturated fatty acids in the seed oil of Camelina sativa (Camelina) was evaluated in the field, in distinct geographical and regulatory locations. A construct, DHA2015.1, containing an optimal combination of biosynthetic genes, was selected for experimental field release in the UK, USA and Canada, and the accumulation of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) determined. The occurrence of these fatty acids in different triacylglycerol species was monitored and found to follow a broad trend irrespective of the agricultural environment. This is a clear demonstration of the stability and robust nature of the transgenic trait for omega-3 long chain polyunsaturated fatty acids in Camelina. Examination of non-seed tissues for the unintended accumulation of EPA and DHA failed to identify their presence in leaf, stem, flower, anther or capsule shell material, confirming the seed-specific accumulation of these novel fatty acids. Collectively, these data confirm the promise of GM plant-based sources of so-called omega-3 fish oils as a sustainable replacement for oceanically derived oils.
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Affiliation(s)
- Lihua Han
- Department of Plant SciencesRothamsted ResearchHarpendenHertsUK
| | - Sarah Usher
- Department of Plant SciencesRothamsted ResearchHarpendenHertsUK
| | - Sjur Sandgrind
- Department of Plant SciencesRothamsted ResearchHarpendenHertsUK
- Present address:
Department of Plant BreedingSwedish University of Agricultural SciencesAlnarpSweden
| | - Kirsty Hassall
- Department of Plant SciencesRothamsted ResearchHarpendenHertsUK
| | - Olga Sayanova
- Department of Plant SciencesRothamsted ResearchHarpendenHertsUK
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7
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Regmi A, Shockey J, Kotapati HK, Bates PD. Oil-Producing Metabolons Containing DGAT1 Use Separate Substrate Pools from those Containing DGAT2 or PDAT. PLANT PHYSIOLOGY 2020; 184:720-737. [PMID: 32732347 PMCID: PMC7536707 DOI: 10.1104/pp.20.00461] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 07/23/2020] [Indexed: 05/03/2023]
Abstract
Seed triacylglycerol (TAG) biosynthesis involves a metabolic network containing multiple different diacylglycerol (DAG) and acyl donor substrate pools. This network of pathways overlaps with those for essential membrane lipid synthesis and utilizes multiple different classes of TAG biosynthetic enzymes. Acyl flux through this network ultimately dictates the final oil fatty acid composition. Most strategies to alter seed oil composition involve the overexpression of lipid biosynthetic enzymes, but how these enzymes are assembled into metabolons and which substrate pools are used by each is still not well understood. To understand the roles of different classes of TAG biosynthetic acyltransferases in seed oil biosynthesis, we utilized the Arabidopsis (Arabidopsis thaliana) diacylglycerol acyltransferase mutant dgat1-1 (in which phosphatidylcholine:diacylglycerol acyltransferase (AtPDAT1) is the major TAG biosynthetic enzyme), and enhanced TAG biosynthesis by expression of Arabidopsis acyltransferases AtDGAT1 and AtDGAT2, as well as the DGAT2 enzymes from soybean (Glycine max), and castor (Ricinus communis), followed by isotopic tracing of glycerol flux through the lipid metabolic network in developing seeds. The results indicate each acyltransferase has a unique effect on seed oil composition. AtDGAT1 produces TAG from a rapidly produced phosphatidylcholine-derived DAG pool. However, AtPDAT1 and plant DGAT2 enzymes utilize a different and larger bulk phosphatidylcholine-derived DAG pool that is more slowly turned over for TAG biosynthesis. Based on metabolic fluxes and protein:protein interactions, our model of TAG synthesis suggests that substrate channeling to select enzymes and spatial separation of different acyltransferases into separate metabolons affect efficient TAG production and oil fatty acid composition.
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Affiliation(s)
- Anushobha Regmi
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406
| | - Jay Shockey
- United States Department of Agriculture, Agricultural Research Service, Southern Regional Research Center, New Orleans, Louisiana 70124
| | - Hari Kiran Kotapati
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164
| | - Philip D Bates
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164
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Ma S, Du C, Ohlrogge J, Zhang M. Accelerating gene function discovery by rapid phenotyping of fatty acid composition and oil content of single transgenic T 1 Arabidopsis and camelina seeds. PLANT DIRECT 2020; 4:e00253. [PMID: 32818167 PMCID: PMC7428496 DOI: 10.1002/pld3.253] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 07/13/2020] [Accepted: 07/17/2020] [Indexed: 05/04/2023]
Abstract
Arabidopsis is wildly used as a model plant and camelina is increasingly used for oilseed research and applications. Although the Arabidopsis genome has been sequenced for two decades, the functions of many lipid-related genes and their regulators have not been well characterized. Improvements in the efficiency and accuracy of gene investigations are key to effective discovery of gene function and downstream bioengineering of plant oil quantity and quality. In this study, a visible marker was used to quickly identify transgenic T1 seeds and a method has been developed to phenotype fatty acid compositions and oil content of single T1 seeds. A whole seed direct transmethylation method was first optimized with multiple seeds and incubation at 85°C for 2 hours in a transmethylation solvent (5% H2SO4 in methanol with 30% toluene cosolvent) is recommended. Based on this method, a single Arabidopsis seed mini-transmethylation (SAST) method has been established in a 1.5 ml GC sample vial with 200 μl transmethylation solvent. Characteristics of the method were evaluated and it was used to phenotype transgenic T1 seeds expressing AtFAD2 or RcWRI1. Our results indicate that fatty acid composition of T1 individual seeds are consistent with those of pools of multiple seeds from higher generations. However, oil content per individual seed varied substantially and therefore pooling five seeds is recommended for phenotyping oil content of T1 seeds. Additionally, a whole camelina single-seed direct transmethylation was evaluated and results confirm its feasibility. The suitability of partial seed analysis of camelina was investigated but variation in composition of different seed tissues limits this approach.
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Affiliation(s)
- Shijie Ma
- College of AgronomyNorthwest A&F UniversityYanglingShaanxiChina
| | - Chang Du
- College of AgronomyNorthwest A&F UniversityYanglingShaanxiChina
- Present address:
School of Life SciencesSouth China Normal UniversityGuangzhouGuangdongChina
| | - John Ohlrogge
- Department of Plant BiologyMichigan State UniversityEast LansingMIUSA
| | - Meng Zhang
- College of AgronomyNorthwest A&F UniversityYanglingShaanxiChina
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Ye Y, Fulcher YG, Sliman DJ, Day MT, Schroeder MJ, Koppisetti RK, Bates PD, Thelen JJ, Van Doren SR. The BADC and BCCP subunits of chloroplast acetyl-CoA carboxylase sense the pH changes of the light-dark cycle. J Biol Chem 2020; 295:9901-9916. [PMID: 32467229 PMCID: PMC7380191 DOI: 10.1074/jbc.ra120.012877] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 05/26/2020] [Indexed: 01/20/2023] Open
Abstract
Acetyl-CoA carboxylase (ACCase) catalyzes the first committed step in the de novo synthesis of fatty acids. The multisubunit ACCase in the chloroplast is activated by a shift to pH 8 upon light adaptation and is inhibited by a shift to pH 7 upon dark adaptation. Here, titrations with the purified ACCase biotin attachment domain-containing (BADC) and biotin carboxyl carrier protein (BCCP) subunits from Arabidopsis indicated that they can competently and independently bind biotin carboxylase (BC) but differ in responses to pH changes representing those in the plastid stroma during light or dark conditions. At pH 7 in phosphate buffer, BADC1 and BADC2 gain an advantage over BCCP1 and BCCP2 in affinity for BC. At pH 8 in KCl solution, however, BCCP1 and BCCP2 had more than 10-fold higher affinity for BC than did BADC1. The pH-modulated shifts in BC preferences for BCCP and BADC partners suggest they contribute to light-dependent regulation of heteromeric ACCase. Using NMR spectroscopy, we found evidence for increased intrinsic disorder of the BADC and BCCP subunits at pH 7. We propose that this intrinsic disorder potentially promotes fast association with BC through a "fly-casting mechanism." We hypothesize that the pH effects on the BADC and BCCP subunits attenuate ACCase activity by night and enhance it by day. Consistent with this hypothesis, Arabidopsis badc1 badc3 mutant lines grown in a light-dark cycle synthesized more fatty acids in their seeds. In summary, our findings provide evidence that the BADC and BCCP subunits function as pH sensors required for light-dependent switching of heteromeric ACCase activity.
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Affiliation(s)
- Yajin Ye
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Yan G Fulcher
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
| | - David J Sliman
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - Mizani T Day
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Mark J Schroeder
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Rama K Koppisetti
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
| | - Philip D Bates
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - Jay J Thelen
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Steven R Van Doren
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
- MU Institute for Data Science and Informatics, University of Missouri, Columbia, Missouri, USA
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Shockey J, Lager I, Stymne S, Kotapati HK, Sheffield J, Mason C, Bates PD. Specialized lysophosphatidic acid acyltransferases contribute to unusual fatty acid accumulation in exotic Euphorbiaceae seed oils. PLANTA 2019; 249:1285-1299. [PMID: 30610363 DOI: 10.1007/s00425-018-03086-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 12/29/2018] [Indexed: 05/20/2023]
Abstract
In vivo and in vitro analyses of Euphorbiaceae species' triacylglycerol assembly enzymes substrate selectivity are consistent with the co-evolution of seed-specific unusual fatty acid production and suggest that many of these genes will be useful for biotechnological production of designer oils. Many exotic Euphorbiaceae species, including tung tree (Vernicia fordii), castor bean (Ricinus communis), Bernardia pulchella, and Euphorbia lagascae, accumulate unusual fatty acids in their seed oils, many of which have valuable properties for the chemical industry. However, various adverse plant characteristics including low seed yields, production of toxic compounds, limited growth range, and poor resistance to abiotic stresses have limited full agronomic exploitation of these plants. Biotechnological production of these unusual fatty acids (UFA) in high yielding non-food oil crops would provide new robust sources for these valuable bio-chemicals. Previous research has shown that expression of the primary UFA biosynthetic gene alone is not enough for high-level accumulation in transgenic seed oils; other genes must be included to drive selective UFA incorporation into oils. Here, we use a series of in planta molecular genetic studies and in vitro biochemical measurements to demonstrate that lysophosphatidic acid acyltransferases from two Euphorbiaceae species have high selectivity for incorporation of their respective unusual fatty acids into the phosphatidic acid intermediate of oil biosynthesis. These results are consistent with the hypothesis that unusual fatty acid accumulation arose in part via co-evolution of multiple oil biosynthesis and assembly enzymes that cooperate to enhance selective fatty acid incorporation into seed oils over that of the common fatty acids found in membrane lipids.
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Affiliation(s)
- Jay Shockey
- United States Department of Agriculture, Agricultural Research Service, Southern Regional Research Center, New Orleans, LA, 70124, USA
| | - 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
| | - Hari Kiran Kotapati
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, MS, 39406, USA
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA
| | - Jennifer Sheffield
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, MS, 39406, USA
| | - Catherine Mason
- United States Department of Agriculture, Agricultural Research Service, Southern Regional Research Center, New Orleans, LA, 70124, USA
| | - Philip D Bates
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, MS, 39406, USA.
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA.
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