1
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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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2
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Córdoba SC, Tong H, Burgos A, Zhu F, Alseekh S, Fernie AR, Nikoloski Z. Identification of gene function based on models capturing natural variability of Arabidopsis thaliana lipid metabolism. Nat Commun 2023; 14:4897. [PMID: 37580345 PMCID: PMC10425450 DOI: 10.1038/s41467-023-40644-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 08/04/2023] [Indexed: 08/16/2023] Open
Abstract
Lipids play fundamental roles in regulating agronomically important traits. Advances in plant lipid metabolism have until recently largely been based on reductionist approaches, although modulation of its components can have system-wide effects. However, existing models of plant lipid metabolism provide lumped representations, hindering detailed study of component modulation. Here, we present the Plant Lipid Module (PLM) which provides a mechanistic description of lipid metabolism in the Arabidopsis thaliana rosette. We demonstrate that the PLM can be readily integrated in models of A. thaliana Col-0 metabolism, yielding accurate predictions (83%) of single lethal knock-outs and 75% concordance between measured transcript and predicted flux changes under extended darkness. Genome-wide associations with fluxes obtained by integrating the PLM in diel condition- and accession-specific models identify up to 65 candidate genes modulating A. thaliana lipid metabolism. Using mutant lines, we validate up to 40% of the candidates, paving the way for identification of metabolic gene function based on models capturing natural variability in metabolism.
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Affiliation(s)
- Sandra Correa Córdoba
- Bioinformatics, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
- Systems Biology and Mathematical Modelling, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany.
| | - Hao Tong
- Bioinformatics, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
- Systems Biology and Mathematical Modelling, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Asdrúbal Burgos
- Department of Zoology and Botany, University of Guadalajara, Guadalajara, Mexico
| | - Feng Zhu
- National R&D Center for Citrus Preservation, Hubei Hongshan Laboratory, National Key Laboratory for Germplasm Innovation and Utilization for Horticultural Crops, Huazhong Agricultural University, Wuhan, China
| | - Saleh Alseekh
- Central Metabolism, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
- Center of Plant Systems Biology and Biotechnology, Plovdiv, 4000, Bulgaria
| | - Alisdair R Fernie
- Central Metabolism, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
- Center of Plant Systems Biology and Biotechnology, Plovdiv, 4000, Bulgaria
| | - Zoran Nikoloski
- Bioinformatics, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
- Systems Biology and Mathematical Modelling, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany.
- Center of Plant Systems Biology and Biotechnology, Plovdiv, 4000, Bulgaria.
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3
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Ying S, Scheible WR, Lundquist PK. A stress-inducible protein regulates drought tolerance and flowering time in Brachypodium and Arabidopsis. PLANT PHYSIOLOGY 2023; 191:643-659. [PMID: 36264121 PMCID: PMC9806587 DOI: 10.1093/plphys/kiac486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 09/25/2022] [Indexed: 06/16/2023]
Abstract
To cope with environmental stresses and ensure maximal reproductive success, plants have developed strategies to adjust the timing of their transition to reproductive growth. This has a substantial impact on the stress resilience of crops and ultimately on agricultural productivity. Here, we report a previously uncharacterized, plant-specific gene family designated as Regulator of Flowering and Stress (RFS). Overexpression of the BdRFS gene in Brachypodium distachyon delayed flowering, increased biomass accumulation, and promoted drought tolerance, whereas clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9)-mediated knockout mutants exhibited opposite phenotypes. A double T-DNA insertional mutant in the two Arabidopsis (Arabidopsis thaliana) homologs replicated the effects on flowering and water deprivation seen in the B. distachyon CRISPR knockout lines, highlighting the functional conservation of the family between monocots and dicots. Lipid analysis of B. distachyon and Arabidopsis revealed that digalactosyldiacylglycerol (DGDG) and phosphatidylcholine (PC) contents were significantly, and reciprocally, altered in overexpressor and knockout mutants. Importantly, alteration of C16:0-containing PC, a Flowering Locus T-interacting lipid, associated with flowering phenotype, with elevated levels corresponding to earlier flowering. Co-immunoprecipitation analysis suggested that BdRFS interacts with phospholipase Dα1 as well as several other abscisic acid-related proteins. Furthermore, reduction of C18:3 fatty acids in DGDG corresponded with reduced jasmonic acid metabolites in CRISPR mutants. Collectively, we suggest that stress-inducible RFS proteins represent a regulatory component of lipid metabolism that impacts several agronomic traits of biotechnological importance.
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Affiliation(s)
- Sheng Ying
- Authors for correspondence: (P.K.L.) and (S.Y.)
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4
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Chu KL, Koley S, Jenkins LM, Bailey SR, Kambhampati S, Foley K, Arp JJ, Morley SA, Czymmek KJ, Bates PD, Allen DK. Metabolic flux analysis of the non-transitory starch tradeoff for lipid production in mature tobacco leaves. Metab Eng 2022; 69:231-248. [PMID: 34920088 PMCID: PMC8761171 DOI: 10.1016/j.ymben.2021.12.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 10/12/2021] [Accepted: 12/11/2021] [Indexed: 12/19/2022]
Abstract
The metabolic plasticity of tobacco leaves has been demonstrated via the generation of transgenic plants that can accumulate over 30% dry weight as triacylglycerols. In investigating the changes in carbon partitioning in these high lipid-producing (HLP) leaves, foliar lipids accumulated stepwise over development. Interestingly, non-transient starch was observed to accumulate with plant age in WT but not HLP leaves, with a drop in foliar starch concurrent with an increase in lipid content. The metabolic carbon tradeoff between starch and lipid was studied using 13CO2-labeling experiments and isotopically nonstationary metabolic flux analysis, not previously applied to the mature leaves of a crop. Fatty acid synthesis was investigated through assessment of acyl-acyl carrier proteins using a recently derived quantification method that was extended to accommodate isotopic labeling. Analysis of labeling patterns and flux modeling indicated the continued production of unlabeled starch, sucrose cycling, and a significant contribution of NADP-malic enzyme to plastidic pyruvate production for the production of lipids in HLP leaves, with the latter verified by enzyme activity assays. The results suggest an inherent capacity for a developmentally regulated carbon sink in tobacco leaves and may in part explain the uniquely successful leaf lipid engineering efforts in this crop.
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Affiliation(s)
- Kevin L Chu
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Somnath Koley
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Lauren M Jenkins
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Sally R Bailey
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA; United States Department of Agriculture-Agriculture Research Service, Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | | | - Kevin Foley
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Jennifer J Arp
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Stewart A Morley
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA; United States Department of Agriculture-Agriculture Research Service, Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Kirk J Czymmek
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA
| | - Philip D Bates
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164-6340, USA
| | - Doug K Allen
- Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA; United States Department of Agriculture-Agriculture Research Service, Donald Danforth Plant Science Center, St. Louis, Missouri, 63132, USA.
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5
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Qu L, Chu YJ, Lin WH, Xue HW. A secretory phospholipase D hydrolyzes phosphatidylcholine to suppress rice heading time. PLoS Genet 2021; 17:e1009905. [PMID: 34879072 PMCID: PMC8654219 DOI: 10.1371/journal.pgen.1009905] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Accepted: 10/21/2021] [Indexed: 11/18/2022] Open
Abstract
Phospholipase D (PLD) hydrolyzes membrane phospholipids and is crucial in various physiological processes and transduction of different signals. Secretory phospholipases play important roles in mammals, however, whose functions in plants remain largely unknown. We previously identified a rice secretory PLD (spPLD) that harbors a signal peptide and here we reported the secretion and function of spPLD in rice heading time regulation. Subcellular localization analysis confirmed the signal peptide is indispensable for spPLD secretion into the extracellular spaces, where spPLD hydrolyzes substrates. spPLD overexpression results in delayed heading time which is dependent on its secretory character, while suppression or deficiency of spPLD led to the early heading of rice under both short-day and long-day conditions, which is consistent with that spPLD overexpression/suppression indeed led to the reduced/increased Hd3a/RFT1 (Arabidopsis Flowing Locus T homolog) activities. Interestingly, rice Hd3a and RFT1 bind to phosphatidylcholines (PCs) and a further analysis by lipidomic approach using mass spectrometry revealed the altered phospholipids profiles in shoot apical meristem, particularly the PC species, under altered spPLD expressions. These results indicate the significance of secretory spPLD and help to elucidate the regulatory network of rice heading time. Secretory phospholipases play essential roles in physiological processes of mammals, while functions of them in plants remain unknown. We identified a rice secretory PLD (spPLD) harboring a signal peptide which is indispensable for secretion of spPLD. Functional studies showed that altered spPLD expression resulted in the changed heading time of rice under both short-day and long-day conditions, which is dependent on the secretory character of spPLD. Rice Hd3a and RFT1, the homologs of Arabidopsis Flowing Locus T (FT), bind to phosphatidylcholine (PC) to promote heading. Analysis of phospholipids profiles in shoot apical meristem by using a mass spectrometry-based lipidomic approach demonstrated that spPLD regulates heading time by hydrolyzing the light period-predominant PC species, further revealing the crucial role of secretory proteins in regulating plant growth and development.
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Affiliation(s)
- Li Qu
- Shanghai Collaborative Innovation Center of Agri-Seeds, Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yu-Jia Chu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Wen-Hui Lin
- School of Life Sciences and Biotechnology, The Joint International Research Laboratory of Metabolic and Developmental Sciences, Joint Center for Single Cell Biology, Shanghai Jiao Tong University, Shanghai, China
- * E-mail: (W-HL); (H-WX)
| | - Hong-Wei Xue
- Shanghai Collaborative Innovation Center of Agri-Seeds, Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- * E-mail: (W-HL); (H-WX)
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6
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Krämer M, Kunz HH. Indirect Export of Reducing Equivalents From the Chloroplast to Resupply NADP for C 3 Photosynthesis-Growing Importance for Stromal NAD(H)? FRONTIERS IN PLANT SCIENCE 2021; 12:719003. [PMID: 34745158 PMCID: PMC8564385 DOI: 10.3389/fpls.2021.719003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/23/2021] [Indexed: 05/06/2023]
Abstract
Plant productivity greatly relies on a flawless concerted function of the two photosystems (PS) in the chloroplast thylakoid membrane. While damage to PSII can be rapidly resolved, PSI repair is complex and time-consuming. A major threat to PSI integrity is acceptor side limitation e.g., through a lack of stromal NADP ready to accept electrons from PSI. This situation can occur when oscillations in growth light and temperature result in a drop of CO2 fixation and concomitant NADPH consumption. Plants have evolved a plethora of pathways at the thylakoid membrane but also in the chloroplast stroma to avoid acceptor side limitation. For instance, reduced ferredoxin can be recycled in cyclic electron flow or reducing equivalents can be indirectly exported from the organelle via the malate valve, a coordinated effort of stromal malate dehydrogenases and envelope membrane transporters. For a long time, the NADP(H) was assumed to be the only nicotinamide adenine dinucleotide coenzyme to participate in diurnal chloroplast metabolism and the export of reductants via this route. However, over the last years several independent studies have indicated an underappreciated role for NAD(H) in illuminated leaf plastids. In part, it explains the existence of the light-independent NAD-specific malate dehydrogenase in the stroma. We review the history of the malate valve and discuss the potential role of stromal NAD(H) for the plant survival under adverse growth conditions as well as the option to utilize the stromal NAD(H) pool to mitigate PSI damage.
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Affiliation(s)
| | - Hans-Henning Kunz
- Department I, Plant Biochemistry and Physiology, Ludwig-Maximilians-University Munich, Munich, Germany
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7
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Duminil P, Davanture M, Oury C, Boex-Fontvieille E, Tcherkez G, Zivy M, Hodges M, Glab N. Arabidopsis thaliana 2,3-bisphosphoglycerate-independent phosphoglycerate mutase 2 activity requires serine 82 phosphorylation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:1478-1489. [PMID: 34174129 DOI: 10.1111/tpj.15395] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 05/18/2021] [Accepted: 05/22/2021] [Indexed: 06/13/2023]
Abstract
Phosphoglycerate mutases (PGAMs) catalyse the reversible isomerisation of 3-phosphoglycerate and 2-phosphoglycerate, a step of glycolysis. PGAMs can be sub-divided into 2,3-bisphosphoglycerate-dependent (dPGAM) and -independent (iPGAM) enzymes. In plants, phosphoglycerate isomerisation is carried out by cytosolic iPGAM. Despite its crucial role in catabolism, little is known about post-translational modifications of plant iPGAM. In Arabidopsis thaliana, phosphoproteomics analyses have previously identified an iPGAM phosphopeptide where serine 82 is phosphorylated. Here, we show that this phosphopeptide is less abundant in dark-adapted compared to illuminated Arabidopsis leaves. In silico comparison of iPGAM protein sequences and 3D structural modelling of AtiPGAM2 based on non-plant iPGAM enzymes suggest a role for phosphorylated serine in the catalytic reaction mechanism. This is confirmed by the activity (or the lack thereof) of mutated recombinant Arabidopsis iPGAM2 forms, affected in different steps of the reaction mechanism. We thus propose that the occurrence of the S82-phosphopeptide reflects iPGAM2 steady-state catalysis. Based on this assumption, the metabolic consequences of a higher iPGAM activity in illuminated versus darkened leaves are discussed.
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Affiliation(s)
- Pauline Duminil
- Institute of Plant Sciences Paris-Saclay (IPS2), INRAe, CNRS, Université Evry, Université Paris-Saclay, Bat 630, Gif sur Yvette, 91190, France
| | - Marlène Davanture
- INRAE, CNRS, AgroParisTech, Université Paris-Saclay, PAPPSO, GQE-Le Moulon, Gif-sur-Yvette, 91190, France
| | - Céline Oury
- Institute of Plant Sciences Paris-Saclay (IPS2), INRAe, CNRS, Université Evry, Université Paris-Saclay, Bat 630, Gif sur Yvette, 91190, France
| | - Edouard Boex-Fontvieille
- Institute of Plant Sciences Paris-Saclay (IPS2), INRAe, CNRS, Université Evry, Université Paris-Saclay, Bat 630, Gif sur Yvette, 91190, France
| | - Guillaume Tcherkez
- Research School of Biology, ANU Joint College of Sciences, Australian National University, Canberra, ACT, 2601, Australia
- Institut de Recherche en Horticulture et Semences, Université d'Angers, INRAe, 42 rue Georges Morel, Beaucouzé, 49070, France
| | - Michel Zivy
- INRAE, CNRS, AgroParisTech, Université Paris-Saclay, PAPPSO, GQE-Le Moulon, Gif-sur-Yvette, 91190, France
| | - Michael Hodges
- Institute of Plant Sciences Paris-Saclay (IPS2), INRAe, CNRS, Université Evry, Université Paris-Saclay, Bat 630, Gif sur Yvette, 91190, France
| | - Nathalie Glab
- Institute of Plant Sciences Paris-Saclay (IPS2), INRAe, CNRS, Université Evry, Université Paris-Saclay, Bat 630, Gif sur Yvette, 91190, France
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8
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Thomas S, Kumar R, Sharma K, Barpanda A, Sreelakshmi Y, Sharma R, Srivastava S. iTRAQ-based proteome profiling revealed the role of Phytochrome A in regulating primary metabolism in tomato seedling. Sci Rep 2021; 11:7540. [PMID: 33824368 PMCID: PMC8024257 DOI: 10.1038/s41598-021-87208-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 03/22/2021] [Indexed: 12/30/2022] Open
Abstract
In plants, during growth and development, photoreceptors monitor fluctuations in their environment and adjust their metabolism as a strategy of surveillance. Phytochromes (Phys) play an essential role in plant growth and development, from germination to fruit development. FR-light (FR) insensitive mutant (fri) carries a recessive mutation in Phytochrome A and is characterized by the failure to de-etiolate in continuous FR. Here we used iTRAQ-based quantitative proteomics along with metabolomics to unravel the role of Phytochrome A in regulating central metabolism in tomato seedlings grown under FR. Our results indicate that Phytochrome A has a predominant role in FR-mediated establishment of the mature seedling proteome. Further, we observed temporal regulation in the expression of several of the late response proteins associated with central metabolism. The proteomics investigations identified a decreased abundance of enzymes involved in photosynthesis and carbon fixation in the mutant. Profound accumulation of storage proteins in the mutant ascertained the possible conversion of sugars into storage material instead of being used or the retention of an earlier profile associated with the mature embryo. The enhanced accumulation of organic sugars in the seedlings indicates the absence of photomorphogenesis in the mutant.
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Affiliation(s)
- Sherinmol Thomas
- Proteomics Lab, Department of Biosciences and Bioengineering, IIT Bombay, Mumbai, Maharashtra, 400076, India
| | - Rakesh Kumar
- Repository of Tomato Genomics Resources, Department of Plant Sciences, University of Hyderabad, Hyderabad, 500046, India
- Deptartment of Life Science, Central University of Karnataka, Kadaganchi, Kalaburagi, Karnataka, 585367, India
| | - Kapil Sharma
- Repository of Tomato Genomics Resources, Department of Plant Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Abhilash Barpanda
- Proteomics Lab, Department of Biosciences and Bioengineering, IIT Bombay, Mumbai, Maharashtra, 400076, India
| | - Yellamaraju Sreelakshmi
- Repository of Tomato Genomics Resources, Department of Plant Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Rameshwar Sharma
- Repository of Tomato Genomics Resources, Department of Plant Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Sanjeeva Srivastava
- Proteomics Lab, Department of Biosciences and Bioengineering, IIT Bombay, Mumbai, Maharashtra, 400076, India.
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9
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Alexander LE, Gilbertson JS, Xie B, Song Z, Nikolau BJ. High spatial resolution imaging of the dynamics of cuticular lipid deposition during Arabidopsis flower development. PLANT DIRECT 2021; 5:e00322. [PMID: 33969255 PMCID: PMC8082717 DOI: 10.1002/pld3.322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 03/17/2021] [Accepted: 03/22/2021] [Indexed: 06/12/2023]
Abstract
The extensive collection of glossy (gl) and eceriferum (cer) mutants of maize and Arabidopsis have proven invaluable in dissecting the branched metabolic pathways that support cuticular lipid deposition. This bifurcated pathway integrates a fatty acid elongation-decarbonylative branch and a fatty acid elongation-reductive branch, which collectively has the capacity to generate hundreds of cuticular lipid metabolites. In this study, a combined transgenic and biochemical strategy was implemented to explore and compare the physiological function of three homologous genes, Gl2, Gl2-like, and CER2, in the context of this branched pathway. These biochemical characterizations integrated new extraction chromatographic procedures with high spatial resolution mass spectrometric imaging methods to profile the cuticular lipids on developing floral tissues transgenically expressing these transgenes in wild-type or cer2 mutant lines of Arabidopsis. Collectively, these datasets establish that both the maize Gl2 and Gl2-like genes are functional homologs of the Arabidopsis CER2 gene. In addition, the dynamic distribution of cuticular lipid deposition follows distinct floral organ localization patterns indicating that the fatty acid elongation-decarbonylative branch of the pathway is differentially localized from the fatty acid elongation-reductive branch of the pathway.
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Affiliation(s)
- Liza E. Alexander
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular BiologyIowa State UniversityAmesIAUSA
- Center for Metabolic BiologyIowa State UniversityAmesIAUSA
| | - Jena S. Gilbertson
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular BiologyIowa State UniversityAmesIAUSA
- Present address:
Illinois College of OptometryChicagoIL60616USA
| | - Bo Xie
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular BiologyIowa State UniversityAmesIAUSA
- Center for Metabolic BiologyIowa State UniversityAmesIAUSA
- Present address:
Office of Intellectual Property and Technology TransferEconomic Development Core FacilityIowa State UniversityAmesIA50010USA
| | - Zhihong Song
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular BiologyIowa State UniversityAmesIAUSA
- Center for Metabolic BiologyIowa State UniversityAmesIAUSA
- Present address:
Office of Pharmaceutical QualityCenter for Drug Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMD20993USA
| | - Basil J. Nikolau
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular BiologyIowa State UniversityAmesIAUSA
- Center for Metabolic BiologyIowa State UniversityAmesIAUSA
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10
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Yu L, Fan J, Zhou C, Xu C. Chloroplast lipid biosynthesis is fine-tuned to thylakoid membrane remodeling during light acclimation. PLANT PHYSIOLOGY 2021; 185:94-107. [PMID: 33631801 PMCID: PMC8133659 DOI: 10.1093/plphys/kiaa013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/21/2020] [Indexed: 05/29/2023]
Abstract
Reprogramming metabolism, in addition to modifying the structure and function of the photosynthetic machinery, is crucial for plant acclimation to changing light conditions. One of the key acclimatory responses involves reorganization of the photosynthetic membrane system including changes in thylakoid stacking. Glycerolipids are the main structural component of thylakoids and their synthesis involves two main pathways localized in the plastid and the endoplasmic reticulum (ER); however, the role of lipid metabolism in light acclimation remains poorly understood. We found that fatty acid synthesis, membrane lipid content, the plastid lipid biosynthetic pathway activity, and the degree of thylakoid stacking were significantly higher in plants grown under low light compared with plants grown under normal light. Plants grown under high light, on the other hand, showed a lower rate of fatty acid synthesis, a higher fatty acid flux through the ER pathway, higher triacylglycerol content, and thylakoid membrane unstacking. We additionally demonstrated that changes in rates of fatty acid synthesis under different growth light conditions are due to post-translational regulation of the plastidic acetyl-CoA carboxylase activity. Furthermore, Arabidopsis mutants defective in one of the two glycerolipid biosynthetic pathways displayed altered growth patterns and a severely reduced ability to remodel thylakoid architecture, particularly under high light. Overall, this study reveals how plants fine-tune fatty acid and glycerolipid biosynthesis to cellular metabolic needs in response to long-term changes in light conditions, highlighting the importance of lipid metabolism in light acclimation.
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Affiliation(s)
- Linhui Yu
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Jilian Fan
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Chao Zhou
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Changcheng Xu
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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11
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Guo L, Du ZH, Wang Z, Lin Z, Guo YL, Chen MJ. Location affects fatty acid composition in Camellia sinensis cv Tieguanyin fresh leaves. Journal of Food Science and Technology 2020; 57:96-101. [PMID: 31975712 DOI: 10.1007/s13197-019-04034-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 07/09/2019] [Accepted: 08/15/2019] [Indexed: 11/30/2022]
Abstract
Tieguanyin tea is a typical representative of oolong tea in China, and is famous for its orchid-like aroma. Fatty acids are one of the important precursors for aroma production. However, fatty acid contents and compositions in Tieguanyin largely remain undefined. In this study, we quantified the fatty acid composition in Tieguanyin and its offspring by gas chromatography-flame ionization detector, and compared the effects of growth sites and harvest time on the leaf fatty acid composition. The results showed that total fatty acid contents in Tieguanyin fresh leaves were higher than its offspring. Growth sites had significant impacts on fatty acid contents. Tieguanyin grown in Anxi County showed higher total fatty acid contents, and higher ratio of total unsaturated fatty acids to total saturated fatty acids. The fresh leaves in the morning showed higher total fatty acid contents compared to samples harvested in the afternoon or evening, suggesting a dynamic fatty acid degradation during day period. During tea processing, unsaturated fatty acids including linolenic acid, linoleic acid and oleic acid (18:1Δ9c) decreased 13.1%, 13.2% and 84.2%, respectively. The ratio of unsaturated fatty acids to saturated fatty acids still was above 300%. We found that Tieguanyin was a typical 18:3 plant, and the higher ratio of unsaturated fatty acids to saturated fatty acids of Tieguanyin grown in Anxi County may contribute to its characteristics aroma.
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Affiliation(s)
- Li Guo
- 1College of Horticulture and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian China.,2Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008 Zhejiang China.,3Horticultural Plant Biology and Metabolomics Center/FAFU-UCR Joint Center, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian China
| | - Zheng-Hua Du
- 1College of Horticulture and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian China.,3Horticultural Plant Biology and Metabolomics Center/FAFU-UCR Joint Center, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian China
| | - Zan Wang
- 1College of Horticulture and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian China
| | - Zhi Lin
- 2Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008 Zhejiang China
| | - Ya-Ling Guo
- 1College of Horticulture and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian China
| | - Ming-Jie Chen
- 1College of Horticulture and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian China.,3Horticultural Plant Biology and Metabolomics Center/FAFU-UCR Joint Center, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian China
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12
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Tietz S, Leuenberger M, Höhner R, Olson AH, Fleming GR, Kirchhoff H. A proteoliposome-based system reveals how lipids control photosynthetic light harvesting. J Biol Chem 2020; 295:1857-1866. [PMID: 31929108 DOI: 10.1074/jbc.ra119.011707] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/09/2020] [Indexed: 11/06/2022] Open
Abstract
Integral membrane proteins are exposed to a complex and dynamic lipid environment modulated by nonbilayer lipids that can influence protein functions by lipid-protein interactions. The nonbilayer lipid monogalactosyldiacylglycerol (MGDG) is the most abundant lipid in plant photosynthetic thylakoid membranes, but its impact on the functionality of energy-converting membrane protein complexes is unknown. Here, we optimized a detergent-based reconstitution protocol to develop a proteoliposome technique that incorporates the major light-harvesting complex II (LHCII) into compositionally well-defined large unilamellar lipid bilayer vesicles to study the impact of MGDG on light harvesting by LHCII. Using steady-state fluorescence spectroscopy, CD spectroscopy, and time-correlated single-photon counting, we found that both chlorophyll fluorescence quantum yields and fluorescence lifetimes clearly indicate that the presence of MGDG in lipid bilayers switches LHCII from a light-harvesting to a more energy-quenching mode that dissipates harvested light into heat. It is hypothesized that in the in vitro system developed here, MGDG controls light harvesting of LHCII by modulating the hydrostatic lateral membrane pressure profile in the lipid bilayer sensed by LHCII-bound peripheral pigments.
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Affiliation(s)
- Stefanie Tietz
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, 99164-6340
| | - Michelle Leuenberger
- Department of Chemistry, University of California, Berkeley, California 94720; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Ricarda Höhner
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, 99164-6340
| | - Alice H Olson
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, 99164-6340
| | - Graham R Fleming
- Department of Chemistry, University of California, Berkeley, California 94720; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, 99164-6340.
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13
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Salvaing J, Botella C, Albrieux C, Gros V, Block MA, Jouhet J. PUB11-Dependent Ubiquitination of the Phospholipid Flippase ALA10 Modifies ALA10 Localization and Affects the Pool of Linolenic Phosphatidylcholine. FRONTIERS IN PLANT SCIENCE 2020; 11:1070. [PMID: 32760418 PMCID: PMC7373794 DOI: 10.3389/fpls.2020.01070] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 06/29/2020] [Indexed: 05/02/2023]
Abstract
Biogenesis of photosynthetic membranes depends on galactolipid synthesis, which relies on several cell compartments, notably the endoplasmic reticulum (ER) and the chloroplast envelope. Galactolipid synthesis involves lipid trafficking between both membrane compartments. In Arabidopsis, ALA10, a phospholipid flippase of the P4 type-ATPase family, counteracts the limitation of monogalactosyldiacylglycerol (MGDG) production and has a positive effect on leaf development. ALA10 locates in distinct domains of the ER depending on the ALIS (ALA interacting subunit) subunit it interacts with: close to the plasma membrane with ALIS1, or next to chloroplasts with ALIS5. It interacts with FAD2 (Fatty acid desaturase 2) and prevents accumulation of linolenic (18:3) containing phosphatidylcholine (PC) stimulating an increase of MGDG synthesis. Here we report that ALA10 interacts with PUB11 (plant U-box type 11), an E3 protein ubiquitin ligase, in vitro and in vivo. ALA10 is however ubiquitinated and degraded by the 26S proteasome in a PUB11-independent process. In pub11 null mutant, the proteasome-dependent degradation of ALA10 is retained and ALA10 is still subject to ubiquitination although its ubiquitination profile appears different. In the absence of PUB11, ALA10 is constrained to the ER close to chloroplasts, which is the usual location when ALA10 is overexpressed. Additionally, in this condition, the decrease of 18:3 containing PC is no longer observed. Taken together these results suggest, that ALA10 contributes in chloroplast-distal ER interacting domains, to reduce the 18:3 desaturation of PC and that PUB11 is involved in reconditioning of ALA10 from chloroplast-proximal to chloroplast-distal ER interacting domains.
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14
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Fan J, Yu L, Xu C. Dual Role for Autophagy in Lipid Metabolism in Arabidopsis. THE PLANT CELL 2019; 31:1598-1613. [PMID: 31036588 PMCID: PMC6635848 DOI: 10.1105/tpc.19.00170] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 03/26/2019] [Accepted: 04/19/2019] [Indexed: 05/18/2023]
Abstract
Autophagy is a major catabolic pathway whereby cytoplasmic constituents including lipid droplets (LDs), storage compartments for neutral lipids, are delivered to the lysosome or vacuole for degradation. The autophagic degradation of cytosolic LDs, a process termed lipophagy, has been extensively studied in yeast and mammals, but little is known about the role for autophagy in lipid metabolism in plants. Organisms maintain a basal level of autophagy under favorable conditions and upregulate the autophagic activity under stress including starvation. Here, we demonstrate that Arabidopsis (Arabidopsis thaliana) basal autophagy contributes to triacylglycerol (TAG) synthesis, whereas inducible autophagy contributes to LD degradation. We found that disruption of basal autophagy impedes organellar membrane lipid turnover and hence fatty acid mobilization from membrane lipids to TAG. We show that lipophagy is induced under starvation as indicated by colocalization of LDs with the autophagic marker and the presence of LDs in vacuoles. We additionally show that lipophagy occurs in a process morphologically resembling microlipophagy and requires the core components of the macroautophagic machinery. Together, this study provides mechanistic insight into lipophagy and reveals a dual role for autophagy in regulating lipid synthesis and turnover in plants.
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Affiliation(s)
- Jilian Fan
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Linhui Yu
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Changcheng Xu
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
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15
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Armarego-Marriott T, Kowalewska Ł, Burgos A, Fischer A, Thiele W, Erban A, Strand D, Kahlau S, Hertle A, Kopka J, Walther D, Reich Z, Schöttler MA, Bock R. Highly Resolved Systems Biology to Dissect the Etioplast-to-Chloroplast Transition in Tobacco Leaves. PLANT PHYSIOLOGY 2019; 180:654-681. [PMID: 30862726 PMCID: PMC6501100 DOI: 10.1104/pp.18.01432] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 02/19/2019] [Indexed: 05/17/2023]
Abstract
Upon exposure to light, plant cells quickly acquire photosynthetic competence by converting pale etioplasts into green chloroplasts. This developmental transition involves the de novo biogenesis of the thylakoid system and requires reprogramming of metabolism and gene expression. Etioplast-to-chloroplast differentiation involves massive changes in plastid ultrastructure, but how these changes are connected to specific changes in physiology, metabolism, and expression of the plastid and nuclear genomes is poorly understood. Here, we describe a new experimental system in the dicotyledonous model plant tobacco (Nicotiana tabacum) that allows us to study the leaf deetiolation process at the systems level. We have determined the accumulation kinetics of photosynthetic complexes, pigments, lipids, and soluble metabolites and recorded the dynamic changes in plastid ultrastructure and in the nuclear and plastid transcriptomes. Our data describe the greening process at high temporal resolution, resolve distinct genetic and metabolic phases during deetiolation, and reveal numerous candidate genes that may be involved in light-induced chloroplast development and thylakoid biogenesis.
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Affiliation(s)
| | - Łucja Kowalewska
- Faculty of Biology, Department of Plant Anatomy and Cytology, University of Warsaw, 02-096 Warszawa, Poland
| | - Asdrubal Burgos
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
- Laboratorio de Biotecnología, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, CP 45200 Zapopan, Jalisco, Mexico
| | - Axel Fischer
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Wolfram Thiele
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Alexander Erban
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Deserah Strand
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Sabine Kahlau
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
- targenomix GmbH, 14476 Potsdam, Germany
| | - Alexander Hertle
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Joachim Kopka
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Dirk Walther
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Ziv Reich
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | | | - Ralph Bock
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
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16
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Karki N, Bates PD. The effect of light conditions on interpreting oil composition engineering in Arabidopsis seeds. PLANT DIRECT 2018; 2:e00067. [PMID: 31245729 PMCID: PMC6508571 DOI: 10.1002/pld3.67] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 05/25/2018] [Accepted: 06/11/2018] [Indexed: 05/20/2023]
Abstract
Arabidopsis thaliana is the most developed and utilized model plant. In particular, it is an excellent model for proof-of-concept seed oil engineering studies because it accumulates approximately 37% seed oil by weight, and it is closely related to important Brassicaceae oilseed crops. Arabidopsis can be grown under a wide variety of conditions including continuous light; however, the amount of light is strongly correlated with total seed oil accumulation. In addition, many attempts to engineer novel seed oil fatty acid compositions in Arabidopsis have reported significant reductions in oil accumulation; however, the relative reduction from the nontransgenic controls varies greatly within the literature. A set of experiments were conducted to systematically analyze the effect of light conditions (including day/night cycle vs. continuous light, and different light intensities) on the relative accumulation of seed oil between three different transgenic lines producing novel hydroxy fatty acids and their nontransgenic background. Oil content was measured per seed and as a percentage of seed weight. Our results indicate the relative amount of seed oil between transgenic lines and nontransgenic controls is dependent on both the light conditions and the type of oil content measurement utilized. In addition, the light conditions effect the relative accumulation of the novel fatty acids between various transgenic lines. Therefore, the success of novel fatty acid proof-of-concept engineering strategies on both oil accumulation and fatty acid composition in Arabidopsis seeds should be considered in light of the select growth and measurement conditions prior to moving engineering strategies into crop plants.
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Affiliation(s)
- Nischal Karki
- Department of Chemistry and BiochemistryThe University of Southern MississippiHattiesburgMississippi
| | - Philip D. Bates
- Department of Chemistry and BiochemistryThe University of Southern MississippiHattiesburgMississippi
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17
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Nakamura Y. Membrane Lipid Oscillation: An Emerging System of Molecular Dynamics in the Plant Membrane. PLANT & CELL PHYSIOLOGY 2018; 59:441-447. [PMID: 29415166 DOI: 10.1093/pcp/pcy023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 01/22/2018] [Indexed: 05/20/2023]
Abstract
Biological rhythm represents a major biological process of living organisms. However, rhythmic oscillation of membrane lipid content is poorly described in plants. The development of lipidomic technology has led to the illustration of precise molecular profiles of membrane lipids under various growth conditions. Compared with conventional lipid signaling, which produces unpredictable lipid changes in response to ever-changing environmental conditions, lipid oscillation generates a fairly predictable lipid profile, adding a new layer of biological function to the membrane system and possible cross-talk with the other chronobiological processes. This mini review covers recent studies elucidating membrane lipid oscillation in plants.
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Affiliation(s)
- Yuki Nakamura
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
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18
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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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19
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Kerr SC, Gaiti F, Beveridge CA, Tanurdzic M. De novo transcriptome assembly reveals high transcriptional complexity in Pisum sativum axillary buds and shows rapid changes in expression of diurnally regulated genes. BMC Genomics 2017; 18:221. [PMID: 28253862 PMCID: PMC5335751 DOI: 10.1186/s12864-017-3577-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 02/09/2017] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND The decision for a bud to grow into a branch is a key regulatory process affecting plant architecture. In order to study molecular processes regulating axillary bud outgrowth in the model plant garden pea (Pisum sativum), we sequenced the axillary bud transcriptome and performed de novo transcriptome assembly. RESULTS We assembled a pea axillary bud transcriptome into 81,774 transcripts comprised of 194,067 isoforms. This new pea transcriptome resource is both comprehensive and representative, as shown by comparison to other available pea sequence resources. Over half of the transcriptome could be annotated based on sequence homology to Arabidopsis thaliana proteins, while almost one quarter of the isoforms were identified as putative long non-coding RNAs (lncRNAs). This transcriptome will be useful in studies of pea buds because it includes genes expressed specifically in buds which are not represented in other transcriptome studies. We also investigated the impact of a short time collection series on gene expression. Differential gene expression analysis identified 142 transcripts changing within the short 170 min time frame that the buds were harvested within. Thirty-three of these transcripts are implicated in diurnal fluctuations in other flowering plants, while the remaining transcripts include 31 putative lncRNA. Further investigation of the differentially expressed transcripts found an enrichment of genes involved in post-transcriptional regulation, including RNA processing and modification, as well as genes involved in fatty acid biosynthesis and oxidative phosphorylation. CONCLUSIONS We have sequenced and assembled a high quality pea bud transcriptome containing both coding and non-coding RNA transcripts that will be useful for further studies into axillary bud outgrowth. Over the short sample collection time frame of just 170 min, we identified differentially expressed coding and non-coding RNA, some of which are implicated in diurnal regulation, highlighting the utility of our transcriptome resource in identifying gene expression changes and informing future experimental designs.
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Affiliation(s)
- Stephanie C. Kerr
- The University of Queensland, School of Biological Sciences, St Lucia, QLD 4072 Australia
| | - Federico Gaiti
- The University of Queensland, School of Biological Sciences, St Lucia, QLD 4072 Australia
| | - Christine A. Beveridge
- The University of Queensland, School of Biological Sciences, St Lucia, QLD 4072 Australia
| | - Milos Tanurdzic
- The University of Queensland, School of Biological Sciences, St Lucia, QLD 4072 Australia
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20
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Salie MJ, Thelen JJ. Regulation and structure of the heteromeric acetyl-CoA carboxylase. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1207-1213. [PMID: 27091637 DOI: 10.1016/j.bbalip.2016.04.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/31/2016] [Accepted: 04/01/2016] [Indexed: 11/16/2022]
Abstract
The enzyme acetyl-CoA carboxylase (ACCase) catalyzes the committed step of the de novo fatty acid biosynthesis (FAS) pathway by converting acetyl-CoA to malonyl-CoA. Two forms of ACCase exist in nature, a homomeric and heteromic form. The heteromeric form of this enzyme requires four different subunits for activity: biotin carboxylase; biotin carboxyl carrier protein; and α- and β-carboxyltransferases. Heteromeric ACCases (htACCase) can be found in prokaryotes and the plastids of most plants. The plant htACCase is regulated by diverse mechanisms reflected by the biochemical and genetic complexity of this multienzyme complex and the plastid stroma where it resides. In this review we summarize the regulation of the plant htACCase and also describe the structural characteristics of this complex from both prokaryotes and plants. 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)
- Matthew J Salie
- Department of Biochemistry, University of Missouri-Columbia, Christopher S. Bond Life Sciences Center, 1201 E. Rollins, Columbia, MO 65201, USA.
| | - Jay J Thelen
- Department of Biochemistry, University of Missouri-Columbia, Christopher S. Bond Life Sciences Center, 1201 E. Rollins, Columbia, MO 65201, USA.
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21
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Allen DK. Assessing compartmentalized flux in lipid metabolism with isotopes. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1226-1242. [PMID: 27003250 DOI: 10.1016/j.bbalip.2016.03.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Revised: 03/13/2016] [Accepted: 03/14/2016] [Indexed: 12/28/2022]
Abstract
Metabolism in plants takes place across multiple cell types and within distinct organelles. The distributions equate to spatial heterogeneity; though the limited means to experimentally assess metabolism frequently involve homogenizing tissues and mixing metabolites from different locations. Most current isotope investigations of metabolism therefore lack the ability to resolve spatially distinct events. Recognition of this limitation has resulted in inspired efforts to advance metabolic flux analysis and isotopic labeling techniques. Though a number of these efforts have been applied to studies in central metabolism; recent advances in instrumentation and techniques present an untapped opportunity to make similar progress in lipid metabolism where the use of stable isotopes has been more limited. These efforts will benefit from sophisticated radiolabeling reports that continue to enrich our knowledge on lipid biosynthetic pathways and provide some direction for stable isotope experimental design and extension of MFA. Evidence for this assertion is presented through the review of several elegant stable isotope studies and by taking stock of what has been learned from radioisotope investigations when spatial aspects of metabolism were considered. The studies emphasize that glycerolipid production occurs across several locations with assembly of lipids in the ER or plastid, fatty acid biosynthesis occurring in the plastid, and the generation of acetyl-CoA and glycerol-3-phosphate taking place at multiple sites. Considering metabolism in this context underscores the cellular and subcellular organization that is important to enhanced production of glycerolipids in plants. An attempt is made to unify salient features from a number of reports into a diagrammatic model of lipid metabolism and propose where stable isotope labeling experiments and further flux analysis may help address questions in the field. 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)
- 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.
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22
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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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23
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Nakamura Y. Function of polar glycerolipids in flower development in Arabidopsis thaliana. Prog Lipid Res 2015; 60:17-29. [DOI: 10.1016/j.plipres.2015.09.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Accepted: 09/22/2015] [Indexed: 11/28/2022]
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24
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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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25
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Effect of total mixed ration composition and daily grazing pattern on milk production, composition and fatty acids profile of dairy cows. J DAIRY RES 2014; 81:471-8. [PMID: 25263635 DOI: 10.1017/s0022029914000399] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The possibilities of using high quality pastures in conjunction with total mixed ration (TMR) during the grazing season have been examined. An experiment with sixteen Holstein cows blocked and randomly assigned to four treatments in a factorial arrangement was conducted in order to evaluate the influence of grazing time of day (day or night) and type of silage (maize or Italian ryegrass) included in the TMR of dairy cows grazing 12 h daily on milk yield, composition and fatty acid profile. The silage type had no effect on the dry matter intake, milk yield and fat and protein proportions. However, cows grazing during the night ate more grass than cows grazing during the day (8·53 vs. 5·65 kg DM/d; P<0·05). No differences were seen between grazing-time with respect to milk production, fat and protein contents. However, the proportion of polyunsaturated fatty acid was higher in milk of dairy cows grazing at night-time than grazing at day-time, especially 18:2n-6 (2·37 vs. 2·12 g/100 g FA respectively, P<0·05) and 18:2cis9trans11 (2·08 vs. 1·74 g/100 g FA respectively, P<0·05).
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26
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Nakamura Y, Andrés F, Kanehara K, Liu YC, Dörmann P, Coupland G. Arabidopsis florigen FT binds to diurnally oscillating phospholipids that accelerate flowering. Nat Commun 2014; 5:3553. [PMID: 24698997 PMCID: PMC3988816 DOI: 10.1038/ncomms4553] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 03/05/2014] [Indexed: 01/21/2023] Open
Abstract
Arabidopsis FT protein is a component of florigen, which transmits photoperiodic flowering signals from leaf companion cells to the shoot apex. Here, we show that FT specifically binds phosphatidylcholine (PC) in vitro. A transgenic approach to increase PC levels in vivo in the shoot meristem accelerates flowering whereas reduced PC levels delay flowering, demonstrating that PC levels are correlated with flowering time. The early flowering is related to FT activity, because expression of FT-effector genes is increased in these plants. Simultaneous increase of FT and PC in the shoot apical meristem further stimulates flowering, whereas a loss of FT function leads to an attenuation of the effect of increased PC. Specific molecular species of PC oscillate diurnally, and night-dominant species are not the preferred ligands of FT. Elevating night-dominant species during the day delays flowering. We suggest that FT binds to diurnally changing molecular species of PC to promote flowering. Daytime flowering in Arabidopsis is stimulated by the secreted protein FT. Nakamura et al. show that FT binds the lipid phosphatidylcholine (PC) in vitro, and that in plants, different PC species predominate during day and night, with daytime species stimulating flowering in a manner that is partially dependent on FT.
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Affiliation(s)
- Yuki Nakamura
- 1] Institute of Plant and Microbial Biology, Academia Sinica, 128 Section 2 Academia Road, Nankang, Taipei 11529, Taiwan [2] Max-Planck-Institute for Plant Breeding Research, Carl-von-Linne-Weg 10, Cologne 50829, Germany [3] Institute of Molecular Physiology and Biotechnology of Plants, University of Bonn, Karlrobert-Kreiten-Strasse 13, Bonn 53115, Germany [4] Japan Science and Technology Agency, PRESTO, 4-8-1 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Fernando Andrés
- Max-Planck-Institute for Plant Breeding Research, Carl-von-Linne-Weg 10, Cologne 50829, Germany
| | - Kazue Kanehara
- Institute of Plant and Microbial Biology, Academia Sinica, 128 Section 2 Academia Road, Nankang, Taipei 11529, Taiwan
| | - Yu-chi Liu
- Institute of Plant and Microbial Biology, Academia Sinica, 128 Section 2 Academia Road, Nankang, Taipei 11529, Taiwan
| | - Peter Dörmann
- Institute of Molecular Physiology and Biotechnology of Plants, University of Bonn, Karlrobert-Kreiten-Strasse 13, Bonn 53115, Germany
| | - George Coupland
- Max-Planck-Institute for Plant Breeding Research, Carl-von-Linne-Weg 10, Cologne 50829, Germany
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Szymanski J, Brotman Y, Willmitzer L, Cuadros-Inostroza Á. Linking gene expression and membrane lipid composition of Arabidopsis. THE PLANT CELL 2014; 26:915-28. [PMID: 24642935 PMCID: PMC4001401 DOI: 10.1105/tpc.113.118919] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Revised: 01/27/2014] [Accepted: 02/17/2014] [Indexed: 05/20/2023]
Abstract
Glycerolipid metabolism of plants responds dynamically to changes in light intensity and temperature, leading to the modification of membrane lipid composition to ensure optimal biochemical and physical properties in the new environment. Although multiple posttranscriptional regulatory mechanisms have been reported to be involved in the process, the contribution of transcriptional regulation remains largely unknown. Here, we present an integrative analysis of transcriptomic and lipidomic data, revealing large-scale coordination between gene expression and changes in glycerolipid levels during the Arabidopsis thaliana response to light and temperature stimuli. Using a multivariate regression technique called O2PLS, we show that the gene expression response is strictly coordinated at the biochemical pathway level and occurs in parallel with changes of specific glycerolipid pools. Five interesting candidate genes were chosen for further analysis from a larger set of candidates identified based on their close association with various groups of glycerolipids. Lipidomic analysis of knockout mutant lines of these five genes showed a significant relationship between the coordination of transcripts and glycerolipid levels in a changing environment and the effects of single gene perturbations.
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Nakamura Y, Andrés F, Kanehara K, Liu YC, Coupland G, Dörmann P. Diurnal and circadian expression profiles of glycerolipid biosynthetic genes in Arabidopsis. PLANT SIGNALING & BEHAVIOR 2014; 9:e29715. [PMID: 25763705 PMCID: PMC4205134 DOI: 10.4161/psb.29715] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Glycerolipid composition in plant membranes oscillates in response to diurnal change. However, its functional significance remained unclear. A recent discovery that Arabidopsis florigen FT binds diurnally oscillating phosphatidylcholine molecules to promote flowering suggests that diurnal oscillation of glycerolipid composition is an important input in flowering time control. Taking advantage of public microarray data, we globally analyzed the expression pattern of glycerolipid biosynthetic genes in Arabidopsis under long-day, short-day, and continuous light conditions. The results revealed that 12 genes associated with glycerolipid metabolism showed significant oscillatory profiles. Interestingly, expression of most of these genes followed circadian profiles, suggesting that glycerolipid biosynthesis is partially under clock regulation. The oscillating expression profile of one representative gene, PECT1, was analyzed in detail. Expression of PECT1 showed a circadian pattern highly correlated with that of the clock-regulated gene GIGANTEA. Thus, our study suggests that a considerable number of glycerolipid biosynthetic genes are under circadian control.
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Affiliation(s)
- Yuki Nakamura
- Institute of Plant and Microbial Biology; Academia Sinica; Nankang, Taipei, Taiwan
- Correspondence to: Yuki Nakamura,
| | - Fernando Andrés
- Max-Planck-Institute for Plant Breeding Research; Cologne, Germany
| | - Kazue Kanehara
- Institute of Plant and Microbial Biology; Academia Sinica; Nankang, Taipei, Taiwan
| | - Yu-chi Liu
- Institute of Plant and Microbial Biology; Academia Sinica; Nankang, Taipei, Taiwan
| | - George Coupland
- Max-Planck-Institute for Plant Breeding Research; Cologne, Germany
| | - Peter Dörmann
- Institute of Molecular Physiology and Biotechnology of Plants; University of Bonn; Bonn, Germany
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Wang X, Xu R, Wang R, Liu A. Transcriptome analysis of Sacha Inchi (Plukenetia volubilis L.) seeds at two developmental stages. BMC Genomics 2012; 13:716. [PMID: 23256450 PMCID: PMC3574040 DOI: 10.1186/1471-2164-13-716] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 12/16/2012] [Indexed: 11/22/2022] Open
Abstract
Background Sacha Inchi (Plukenetia volubilis L., Euphorbiaceae) is a potential oilseed crop because the seeds of this plant are rich in unsaturated fatty acids (FAs). In particular, the fatty acid composition of its seed oil differs markedly in containing large quantities of α-linolenic acid (18C:3, a kind of ω-3 FAs). However, little is known about the molecular mechanisms responsible for biosynthesis of unsaturated fatty acids in the developing seeds of this species. Transcriptome data are needed to better understand these mechanisms. Results In this study, de novo transcriptome assembly and gene expression analysis were performed using Illumina sequencing technology. A total of 52.6 million 90-bp paired-end reads were generated from two libraries constructed at the initial stage and fast oil accumulation stage of seed development. These reads were assembled into 70,392 unigenes; 22,179 unigenes showed a 2-fold or greater expression difference between the two libraries. Using this data we identified unigenes that may be involved in de novo FA and triacylglycerol biosynthesis. In particular, a number of unigenes encoding desaturase for formation of unsaturated fatty acids with high expression levels in the fast oil accumulation stage compared with the initial stage of seed development were identified. Conclusions This study provides the first comprehensive dataset characterizing Sacha Inchi gene expression at the transcriptional level. These data provide the foundation for further studies on molecular mechanisms underlying oil accumulation and PUFA biosynthesis in Sacha Inchi seeds. Our analyses facilitate understanding of the molecular mechanisms responsible for the high unsaturated fatty acids (especially α-linolenic acid) accumulation in Sacha Inchi seeds.
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Affiliation(s)
- Xiaojuan Wang
- Key Laboratory of Tropical Plant Resource Science, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, 88 Xuefu Road, Kunming 650223, China
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Tjellström H, Yang Z, Allen DK, Ohlrogge JB. Rapid kinetic labeling of Arabidopsis cell suspension cultures: implications for models of lipid export from plastids. PLANT PHYSIOLOGY 2012; 158:601-11. [PMID: 22128138 PMCID: PMC3271753 DOI: 10.1104/pp.111.186122] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 11/22/2011] [Indexed: 05/18/2023]
Abstract
Cell cultures allow rapid kinetic labeling experiments that can provide information on precursor-product relationships and intermediate pools. T-87 suspension cells are increasingly used in Arabidopsis (Arabidopsis thaliana) research, but there are no reports describing their lipid composition or biosynthesis. To facilitate application of T-87 cells for analysis of glycerolipid metabolism, including tests of gene functions, we determined composition and accumulation of lipids of light- and dark-grown cultures. Fatty acid synthesis in T-87 cells was 7- to 8-fold higher than in leaves. Similar to other plant tissues, phosphatidylcholine (PC) and phosphatidylethanolamine were major phospholipids, but galactolipid levels were 3- to 4-fold lower than Arabidopsis leaves. Triacylglycerol represented 10% of total acyl chains, a greater percentage than in most nonseed tissues. The initial steps in T-87 cell lipid assembly were evaluated by pulse labeling cultures with [(14)C]acetate and [(14)C]glycerol. [(14)C]acetate was very rapidly incorporated into PC, preferentially at sn-2 and without an apparent precursor-product relationship to diacylglycerol (DAG). By contrast, [(14)C]glycerol most rapidly labeled DAG. These results indicate that acyl editing of PC is the major pathway for initial incorporation of fatty acids into glycerolipids of cells derived from a 16:3 plant. A very short lag time (5.4 s) for [(14)C]acetate labeling of PC implied channeled incorporation of acyl chains without mixing with the bulk acyl-CoA pool. Subcellular fractionation of pea (Pisum sativum) leaf protoplasts indicated that 30% of lysophosphatidylcholine acyltransferase activity colocalized with chloroplasts. Together, these data support a model in which PC participates in trafficking of newly synthesized acyl chains from plastids to the endoplasmic reticulum.
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Maatta S, Scheu B, Roth MR, Tamura P, Li M, Williams TD, Wang X, Welti R. Levels of Arabidopsis thaliana Leaf Phosphatidic Acids, Phosphatidylserines, and Most Trienoate-Containing Polar Lipid Molecular Species Increase during the Dark Period of the Diurnal Cycle. FRONTIERS IN PLANT SCIENCE 2012. [PMID: 22629276 DOI: 10.3389/fpls.2012.00049/full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Previous work has demonstrated that plant leaf polar lipid fatty acid composition varies during the diurnal (dark-light) cycle. Fatty acid synthesis occurs primarily during the light, but fatty acid desaturation continues in the absence of light, resulting in polyunsaturated fatty acids reaching their highest levels toward the end of the dark period. In this work, Arabidopsis thaliana were grown at constant (21°C) temperature with 12-h light and 12-h dark periods. Collision induced dissociation time-of-flight mass spectrometry (MS) demonstrated that 16:3 and 18:3 fatty acid content in membrane lipids of leaves are higher at the end of the dark than at the end of the light period, while 16:1, 16:2, 18:0, and 18:1 content are higher at the end of the light period. Lipid profiling of membrane galactolipids, phospholipids, and lysophospholipids by electrospray ionization triple quadrupole MS indicated that the monogalactosyldiacylglycerol, phosphatidylglycerol, and phosphatidylcholine classes include molecular species whose levels are highest at end of the light period and others that are highest at the end of the dark period. The levels of phosphatidic acid (PA) and phosphatidylserine classes were higher at the end of the dark period, and molecular species within these classes either followed the class pattern or were not significantly changed in the diurnal cycle. Phospholipase D (PLD) is a family of enzymes that hydrolyzes phospholipids to produce PA. Analysis of several PLD mutant lines suggests that PLDζ2 and possibly PLDα1 may contribute to diurnal cycling of PA. The polar lipid compositional changes are considered in relation to recent data that demonstrate phosphatidylcholine acyl editing.
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Affiliation(s)
- Sara Maatta
- Division of Biology, Kansas Lipidomics Research Center, Kansas State University Manhattan, KS, USA
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32
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Maatta S, Scheu B, Roth MR, Tamura P, Li M, Williams TD, Wang X, Welti R. Levels of Arabidopsis thaliana Leaf Phosphatidic Acids, Phosphatidylserines, and Most Trienoate-Containing Polar Lipid Molecular Species Increase during the Dark Period of the Diurnal Cycle. FRONTIERS IN PLANT SCIENCE 2012; 3:49. [PMID: 22629276 PMCID: PMC3355531 DOI: 10.3389/fpls.2012.00049] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Accepted: 02/27/2012] [Indexed: 05/18/2023]
Abstract
Previous work has demonstrated that plant leaf polar lipid fatty acid composition varies during the diurnal (dark-light) cycle. Fatty acid synthesis occurs primarily during the light, but fatty acid desaturation continues in the absence of light, resulting in polyunsaturated fatty acids reaching their highest levels toward the end of the dark period. In this work, Arabidopsis thaliana were grown at constant (21°C) temperature with 12-h light and 12-h dark periods. Collision induced dissociation time-of-flight mass spectrometry (MS) demonstrated that 16:3 and 18:3 fatty acid content in membrane lipids of leaves are higher at the end of the dark than at the end of the light period, while 16:1, 16:2, 18:0, and 18:1 content are higher at the end of the light period. Lipid profiling of membrane galactolipids, phospholipids, and lysophospholipids by electrospray ionization triple quadrupole MS indicated that the monogalactosyldiacylglycerol, phosphatidylglycerol, and phosphatidylcholine classes include molecular species whose levels are highest at end of the light period and others that are highest at the end of the dark period. The levels of phosphatidic acid (PA) and phosphatidylserine classes were higher at the end of the dark period, and molecular species within these classes either followed the class pattern or were not significantly changed in the diurnal cycle. Phospholipase D (PLD) is a family of enzymes that hydrolyzes phospholipids to produce PA. Analysis of several PLD mutant lines suggests that PLDζ2 and possibly PLDα1 may contribute to diurnal cycling of PA. The polar lipid compositional changes are considered in relation to recent data that demonstrate phosphatidylcholine acyl editing.
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Affiliation(s)
- Sara Maatta
- Division of Biology, Kansas Lipidomics Research Center, Kansas State UniversityManhattan, KS, USA
| | - Brad Scheu
- Division of Biology, Kansas Lipidomics Research Center, Kansas State UniversityManhattan, KS, USA
| | - Mary R. Roth
- Division of Biology, Kansas Lipidomics Research Center, Kansas State UniversityManhattan, KS, USA
| | - Pamela Tamura
- Division of Biology, Kansas Lipidomics Research Center, Kansas State UniversityManhattan, KS, USA
| | - Maoyin Li
- Donald Danforth Plant Science CenterSt. Louis, MO, USA
- Department of Biology, University of Missouri-St. LouisSt. Louis, MO, USA
| | - Todd D. Williams
- Mass Spectrometry Laboratory, University of KansasLawrence, KS, USA
| | - Xuemin Wang
- Donald Danforth Plant Science CenterSt. Louis, MO, USA
- Department of Biology, University of Missouri-St. LouisSt. Louis, MO, USA
| | - Ruth Welti
- Division of Biology, Kansas Lipidomics Research Center, Kansas State UniversityManhattan, KS, USA
- *Correspondence: Ruth Welti, Division of Biology, Kansas Lipidomics Research Center, Kansas State University, Manhattan, KS 66506-4901, USA. e-mail:
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33
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Chapman KD, Ohlrogge JB. Compartmentation of triacylglycerol accumulation in plants. J Biol Chem 2011; 287:2288-94. [PMID: 22090025 DOI: 10.1074/jbc.r111.290072] [Citation(s) in RCA: 290] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Triacylglycerols from plants, familiar to most people as vegetable oils, supply 25% of dietary calories to the developed world and are increasingly a source for renewable biomaterials and fuels. Demand for vegetable oils will double by 2030, which can be met only by increased oil production. Triacylglycerol synthesis is accomplished through the coordinate action of multiple pathways in multiple subcellular compartments. Recent information has revealed an underappreciated complexity in pathways for synthesis and accumulation of this important energy-rich class of molecules.
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Affiliation(s)
- Kent D Chapman
- Department of Biological Sciences, Center for Plant Lipid Research, University of North Texas, Denton, Texas 76203-5017, USA.
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Burgos A, Szymanski J, Seiwert B, Degenkolbe T, Hannah MA, Giavalisco P, Willmitzer L. Analysis of short-term changes in the Arabidopsis thaliana glycerolipidome in response to temperature and light. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 66:656-68. [PMID: 21309866 DOI: 10.1111/j.1365-313x.2011.04531.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Although the influence of temperature, particularly cold, on lipid metabolism is well established, previous studies have focused on long-term responses and have largely ignored the influence of other interacting environmental factors. Here, we present a time-resolved analysis of the early responses of the glycerolipidome of Arabidopsis thaliana plants exposed to various temperatures (4, 21 and 32°C) and light intensities (darkness, 75, 150 and 400 μmol m(-2) s(-1)), including selected combinations. Using a UPLC/MS-based lipidomic platform, we reproducibly measured most glycerolipid species reported for Arabidopsis leaves, including the classes phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI) phosphatidylglycerol (PG), monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG) and sulfoquinovosyldiacylglycerol (SQDG). In addition to known lipids, we have identified previously unobserved compounds, such as 36-C PGs and eukaryotic phospholipids containing 16:3 acyl chains. Occurrence of these lipid species implies the action of new biochemical mechanisms. Exposition of Arabidopsis plants to various light and temperature regimes results in two major effects. The first is the dependence of the saturation level of PC and MGDG pools on light intensity, likely arising from light regulation of de novo fatty acid synthesis. The second concerns an immediate decrease in unsaturated species of PG at high-temperature conditions (32°C), which could mark the first stages of adaptation to heat-stress conditions. Observed changes are discussed in the context of current knowledge, and new hypotheses have been formulated concerning the early stages of the plant response to changing light and temperature conditions.
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Affiliation(s)
- Asdrubal Burgos
- Max Planck Institute of Molecular Plant Physiology, 14424 Potsdam-Golm, Germany
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35
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A Snapshot in Time of Fatty Acids Composition of Grass Herbage as Affected by Time of Day. ACTA ACUST UNITED AC 2008. [DOI: 10.15232/s1080-7446(15)30921-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Scharnewski M, Pongdontri P, Mora G, Hoppert M, Fulda M. Mutants of Saccharomyces cerevisiae deficient in acyl-CoA synthetases secrete fatty acids due to interrupted fatty acid recycling. FEBS J 2008; 275:2765-78. [PMID: 18422644 DOI: 10.1111/j.1742-4658.2008.06417.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In the present study, acyl-CoA synthetase mutants of Saccharomyces cerevisiae were employed to investigate the impact of this activity on certain pools of fatty acids. We identified a genotype responsible for the secretion of free fatty acids into the culture medium. The combined deletion of Faa1p and Faa4p encoding two out of five acyl-CoA synthetases was necessary and sufficient to establish mutant cells that secreted fatty acids in a growth-phase dependent manner. The mutants accomplished fatty acid export during exponential growth-phase followed by fatty acid re-import into the cells during the stationary phase. The data presented suggest that the secretion is driven by an active component. The fatty acid re-import resulted in a severely altered ultrastructure of the mutant cells. Additional strains deficient of any cellular acyl-CoA synthetase activity revealed an almost identical phenotype, thereby proving transfer of fatty acids across the plasma membrane independent of their activation with CoA. Further experiments identified membrane lipids as the origin of the observed free fatty acids. Therefore, we propose the recycling of endogenous fatty acids generated in the course of lipid remodelling as a major task of both acyl-CoA synthetases Faa1p and Faa4p.
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Affiliation(s)
- Michael Scharnewski
- Department of Plant Biochemistry, Albrecht-von-Haller Institute, Georg-August University Goettingen, Germany
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Erfani F, Hassandokht MR, Jabbari A, Barzegar M. Effect of cultivar on chemical composition of some Iranian spinach. Pak J Biol Sci 2007; 10:602-606. [PMID: 19069542 DOI: 10.3923/pjbs.2007.602.606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
This research was carried out to determine fatty acids, phenolic compounds, oxalic acid, protein, fat, total fiber and mineral elements of Iranian spinach cultivars (Varamin 1, Varamin 2, Varamin 3, Zabol, Kashan, Qom and Zanjan). Results showed that cultivar Zabol had the highest protein (2.59%). The highest fat percentage, phenolic compounds, P, linoleic acid (18:2) and the lowest oxalic acid were found in cultivar Kashan. Cultivar Varamin 2 had the highest total fiber (2.22%). Dry matter, K, Ca, Cu and Zn contents of cultivar Zanjan were higher than the other cultivars. Cultivar Qom had the highest amounts of Mg and Fe. Cultivar Varamin 3 had the highest Na (93.8 mg/100 g fw). Cultivars Qom and Varamin l had the highest percentage of linolenic acid (18:3). Present results for chemical composition of studied cultivars, were similar to values reported by other researchers.
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Affiliation(s)
- F Erfani
- Department of Chemistry, K.N. Toosi Technology University, Tehran, Iran
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Ekman Å, Bülow L, Stymne S. Elevated atmospheric CO(2) concentration and diurnal cycle induce changes in lipid composition in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2007; 174:591-599. [PMID: 17447914 DOI: 10.1111/j.1469-8137.2007.02027.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Few studies regarding the effects of elevated atmospheric CO(2) concentrations on plant lipid metabolism have been carried out. Here, the effects of elevated CO(2) concentration on lipid composition in mature seeds and in leaves during the diurnal cycle of Arabidopsis thaliana were investigated. Plants were grown in controlled climate chambers at elevated (800 ppm) and ambient CO(2) concentrations. Lipids were extracted and characterized using thin layer chromatography (TLC) and gas liquid chromatography. The fatty acid profile of total leaf lipids showed large diurnal variations. However, the elevated CO(2) concentration did not induce any significant differences in the diurnal pattern compared with the ambient concentration. The major chloroplast lipids monogalactosyldiacylglycerol (MGDG) and phosphatidylglycerol (PG) were decreased at elevated CO(2) in favour of phosphatidylcholine (PC) and phosphatidylethanolamine (PE). Elevated CO(2) produced a 25% lower ratio of 16:1trans to 16:0 in PG compared with the ambient concentration. With good nutrient supply, growth at elevated CO(2) did not significantly affect single seed weight, total seed mass, oil yield per seed, or the fatty acid profile of the seeds. This study has shown that elevated CO(2) induced changes in leaf lipid composition in A. thaliana, whereas seed lipids were unaffected.
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Affiliation(s)
- Åsa Ekman
- Department of Crop Science, Swedish University of Agricultural Sciences, PO Box 44, SE-23053 Alnarp, Sweden
- Department of Pure and Applied Biochemistry, Centre for Chemistry and Chemical Engineering, Lund University, PO Box 124, SE-22100 Lund, Sweden
| | - Leif Bülow
- Department of Pure and Applied Biochemistry, Centre for Chemistry and Chemical Engineering, Lund University, PO Box 124, SE-22100 Lund, Sweden
| | - Sten Stymne
- Department of Crop Science, Swedish University of Agricultural Sciences, PO Box 44, SE-23053 Alnarp, Sweden
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Banas A, Debski H, Banas W, Heneen WK, Dahlqvist A, Bafor M, Gummeson PO, Marttila S, Ekman A, Carlsson AS, Stymne S. Lipids in grain tissues of oat (Avena sativa): differences in content, time of deposition, and fatty acid composition. JOURNAL OF EXPERIMENTAL BOTANY 2007; 58:2463-70. [PMID: 17586606 DOI: 10.1093/jxb/erm125] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Oat (Avena sativa) is unusual in comparison with other cereals since there are varieties with up to 18% oil content. The lipid content and fatty acid composition in different parts of the grain during seed development were characterized in cultivars Freja (6% oil) and Matilda (10% oil), using thin-layer and gas chromatography, and light and electron microscopy. The majority of lipids (86-90%) were found in the endosperm. Ninety-five per cent of the higher oil content of cv. Matilda compared with cv. Freja was due to increased oil content of the endosperm. Up to 84% of the lipids were deposited during the first half of seed development, when seeds where still green with a milky endosperm. Microscopy studies revealed that whereas oil bodies of the embryo and scutellum still contained a discrete shape upon grain maturation, oil bodies of the endosperms fused upon maturation and formed smears of oil.
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Affiliation(s)
- Antoni Banas
- Institute of Biology and Environmental Protection, AP, ul Arciszewskiego 22, 76-200, Slupsk, Poland
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Ghassemian M, Lutes J, Tepperman JM, Chang HS, Zhu T, Wang X, Quail PH, Lange BM. Integrative analysis of transcript and metabolite profiling data sets to evaluate the regulation of biochemical pathways during photomorphogenesis. Arch Biochem Biophys 2006; 448:45-59. [PMID: 16460663 DOI: 10.1016/j.abb.2005.11.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 10/24/2005] [Accepted: 11/01/2005] [Indexed: 10/25/2022]
Abstract
One of the key developmental processes during photomorphogenesis is the differentiation of prolamellar bodies of proplastids into thylakoid membranes containing the photosynthetic pigment-protein complexes of chloroplasts. To study the regulatory events controlling pigment-protein complex assembly, including the biosynthesis of metabolic precursors and pigment end products, etiolated Arabidopsis thaliana seedlings were irradiated with continuous red light (Rc), which led to rapid greening, or continuous far-red light (FRc), which did not result in visible greening, and subjected to analysis by oligonucleotide microarrays and targeted metabolite profiling. An analysis using BioPathAt, a bioinformatic tool that allows the visualization of post-genomic data sets directly on biochemical pathway maps, indicated that in Rc-treated seedlings mRNA expression and metabolite patterns were tightly correlated (e.g., Calvin cycle, biosynthesis of chlorophylls, carotenoids, isoprenoid quinones, thylakoid lipids, sterols, and amino acids). K-means clustering revealed that gene expression patterns across various biochemical pathways were very similar in Rc- and FRc-treated seedlings (despite the visible phenotypic differences), whereas a principal component analysis of metabolite pools allowed a clear distinction between both treatments (in accordance with the visible phenotype). Our results illustrate the general importance of integrative approaches to correlate post-genomic data sets with phenotypic outcomes.
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Affiliation(s)
- Majid Ghassemian
- Torrey Mesa Research Institute, 3115 Merryfield Row, San Diego, CA 92121, USA
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Geigenberger P, Kolbe A, Tiessen A. Redox regulation of carbon storage and partitioning in response to light and sugars. JOURNAL OF EXPERIMENTAL BOTANY 2005; 56:1469-79. [PMID: 15863446 DOI: 10.1093/jxb/eri178] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Redox signals generated by the photosynthetic electron transport chain are known to be involved in regulating the Calvin cycle, ATP synthesis, and NADPH export from chloroplasts in response to light. The signal cascade involves transfer of electrons from photosystem I via the ferredoxin-thioredoxin system to target enzymes that are activated by reduction of regulatory disulphide bonds. The purpose of this review is to discuss recent findings showing that this concept can be extended to the regulation of carbon storage and partitioning in plants. Starch is the major carbon store in plants, and ADP-glucose pyrophosphorylase (AGPase) is the key regulatory enzyme of starch synthesis in the plastid. It has been shown that AGPase from potato tubers is subject to post-translational redox modification, and here experimental data will be provided showing that the isozyme from pea leaf chloroplasts is activated by reduced thioredoxin f or m in a similar way. Recent reports will be summarized providing in planta evidence that this mechanism regulates storage starch synthesis in response to light and sugars. Post-translational redox activation of AGPase in response to sugars is part of a signalling mechanism linking the rate of starch synthesis to the availability of carbon in diverse plant tissues. Some of the components of the signalling pathway reporting changes in the cytosolic sugar status to the plastid have been postulated, but detailed work is in progress to confirm the exact mode of action. Recent evidence will be discussed showing that key enzymes of de novo fatty acid synthesis (acetyl-CoA carboxylase) and ammonium assimilation (glutamine synthetase and glutamine:oxoglutarate amino transferase) are regulated by reversible disulphide-bond formation similar to AGPase. Redox regulation is proposed to be the preferred strategy of plastidial enzymes to regulate various metabolic processes such as carbon fixation, starch metabolism, lipid synthesis, and amino acid synthesis in response to physiological and environmental inputs.
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Affiliation(s)
- Peter Geigenberger
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Golm, Germany.
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Bonaventure G, Bao X, Ohlrogge J, Pollard M. Metabolic responses to the reduction in palmitate caused by disruption of the FATB gene in Arabidopsis. PLANT PHYSIOLOGY 2004; 135:1269-79. [PMID: 15266055 PMCID: PMC519046 DOI: 10.1104/pp.104.043372] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2004] [Revised: 04/13/2004] [Accepted: 04/13/2004] [Indexed: 05/18/2023]
Abstract
Disruption of the FATB gene in Arabidopsis results in a two-thirds reduction in saturated fatty acids, largely palmitate, in the leaf extra-plastidic phospholipids and a reduction in the growth rate of the mutant compared to wild type (Bonaventure G, Salas JJ, Pollard MR, Ohlrogge JB [2003] Plant Cell 15: 1020-1033). In this study, we report that although fatb-ko seedlings grow more slowly than wild type, the rate of fatty acid synthesis in leaves of the mutant increases by 40%. This results in approximately the same amount of palmitate exported from the plastid as in wild type but an increase in oleate export of about 55%. To maintain constant amounts of fatty acids in leaves, thereby counterbalancing their higher rate of production, the mutant also increases its rate of fatty acid degradation. Although fatb-ko leaves have higher rates of fatty acid synthesis and turnover, the relative proportions of membrane lipids are similar to wild type. Thus, homeostatic mechanisms to preserve membrane compositions compensate for substantial changes in rates of fatty acid and glycerolipid metabolism in the mutant. Pulse-chase labeling studies show that in fatb-ko leaves there is a net increase in the synthesis of both prokaryotic and eukaryotic lipids and consequently of their turnover. The net loss of palmitate from phosphatidylcholine plus phosphatidylethanolamine is similar for wild type and mutant, suggesting that mechanisms are not present that can preferentially preserve the saturated fatty acids. In summary, the leaf cell responds to the loss of saturated fatty acid production in the fatb-ko mutant by increasing both fatty acid synthesis and degradation, but in doing so the mechanisms for increased fatty acid turnover contribute to the lowering of the percentage of saturated fatty acids found in eukaryotic lipids.
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Affiliation(s)
- Gustavo Bonaventure
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824, USA
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Abstract
The model for export of fatty acids from plastids proposes that the acyl-ACP (acyl carrier protein) product of de novo fatty acid synthesis is hydrolyzed in the stroma by acyl-ACP thioesterases and the free fatty acid (FFA) released is then transferred to the outer envelope of the plastid where it is reactivated to acyl-CoA for utilization in cytosolic glycerolipid synthesis. Experiments were performed to assess whether the delivery of nascent FFA from the stroma for long chain acyl-CoA synthesis (LACS) occurs via simple diffusion or a more complex mechanism. The flux through the in vivo FFA pool was estimated using kinetic labeling experiments with spinach and pea leaves. The maximum half-life for FFA in the export pool was < or =1 s. Isolated pea chloroplasts incubated in the light with [14C]acetate gave a linear accumulation of FFA. When CoASH and ATP were present there was also a linear accumulation of acyl-CoA thioesters (plus derived polar lipids), with no measurable lag phase (<30 s), indicating that the FFA pool supplying LACS rapidly reached steady state. The LACS reaction was also measured independently in the dark after in situ generated FFA had accumulated yielding estimates of LACS substrate-velocity relationships. Based on these experiments the LACS reaction with in situ generated FFA as substrate is only about 3% of the LACS activity required in vivo at the very low concentrations of the FFA export pool calculated from the in vivo experiment. Furthermore, bovine serum albumin rapidly removed in situ generated FFA from chloroplasts, but could not compete effectively for "nascent" FFA substrates of LACS. Together the data suggest a locally channeled pool of exported FFA that is closely linked to LACS.
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Affiliation(s)
- Abraham J K Koo
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824-1312, USA
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Abstract
Biotin-containing proteins are found in all forms of life, and they catalyze carboxylation, decarboxylation, or transcarboxylation reactions that are central to metabolism. In plants, five biotin-containing proteins have been characterized. Of these, four are catalysts, namely the two structurally distinct acetyl-CoA carboxylases (heteromeric and homomeric), 3-methylcrotonyl-CoA carboxylase and geranoyl-CoA carboxylase. In addition, plants contain a noncatalytic biotin protein that accumulates in seeds and is thought to play a role in storing biotin. Acetyl-CoA carboxylases generate two pools of malonyl-CoA, one in plastids that is the precursor for de novo fatty acid biosynthesis and the other in the cytosol that is the precursor for fatty acid elongation and a large number of secondary metabolites. 3-Methylcrotonyl-CoA carboxylase catalyzes a reaction in the mitochondrial pathway for leucine catabolism. The exact metabolic function of geranoyl-CoA carboxylase is as yet unknown, but it may be involved in isoprenoid metabolism. This minireview summarizes the recent developments in our understanding of the structure, regulation, and metabolic functions of these proteins in plants.
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Branen JK, Shintani DK, Engeseth NJ. Expression of antisense acyl carrier protein-4 reduces lipid content in Arabidopsis leaf tissue. PLANT PHYSIOLOGY 2003; 132:748-56. [PMID: 12805604 PMCID: PMC167014 DOI: 10.1104/pp.102.018622] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2002] [Revised: 12/08/2002] [Accepted: 12/08/2002] [Indexed: 05/18/2023]
Abstract
Arabidopsis plants were transformed with acyl carrier protein (ACP)-4 in antisense conformation driven by the cauliflower mosaic virus 35S promoter. It was hypothesized that reduction of ACP4 in leaf tissue would result in a reduction in lipid biosynthesis and, in addition, affect fatty acid composition and leaf physiology. Several transgenic lines have been generated with reduced ACP4 protein in leaf tissue. Dramatic reductions in ACP4 resulted in a reduction of leaf lipid content (22%-60%) based on fresh leaf weight and a bleached appearance and reduced photosynthetic efficiency. In addition, a decrease in 16:3 as a percentage of the total fatty acid composition was noted. There were no changes in leaf lipid class distribution; however, there was a decrease in the relative amount of 16:3 in monogalactosyldiacylglycerol. These results suggest that ACP4 plays a major role in the biosynthesis of fatty acids for chloroplast membrane development. Alterations in the ACP isoform profile of Arabidopsis leaf also appear to alter the flow of fatty acids between the prokaryotic and eukaryotic pathways for assembly of galactolipids. However, it has not yet been determined if the changes in fatty acid composition are due to changes in the profile of ACP isoforms, or if they are actually a reaction to a reduction in fatty acid precursors.
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Affiliation(s)
- Jill K Branen
- Department of Food Science and Human Nutrition, University of Illinois, 259 Edward R. Madigan Library, 1201 West Gregory Drive, Urbana 61801, USA
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Schnurr JA, Shockey JM, de Boer GJ, Browse JA. Fatty acid export from the chloroplast. Molecular characterization of a major plastidial acyl-coenzyme A synthetase from Arabidopsis. PLANT PHYSIOLOGY 2002; 129:1700-9. [PMID: 12177483 PMCID: PMC166758 DOI: 10.1104/pp.003251] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2002] [Revised: 03/12/2002] [Accepted: 04/22/2002] [Indexed: 05/18/2023]
Abstract
Acyl-coenzyme A (CoA) synthetases (ACSs, EC 6.2.1.3) catalyze the formation of fatty acyl-CoAs from free fatty acid, ATP, and CoA. Essentially all de novo fatty acid synthesis occurs in the plastid. Fatty acids destined for membrane glycerolipid and triacylglycerol synthesis in the endoplasmic reticulum must be first activated to acyl-CoAs via an ACS. Within a family of nine ACS genes from Arabidopsis, we identified a chloroplast isoform, LACS9. LACS9 is highly expressed in developing seeds and young rosette leaves. Both in vitro chloroplast import assays and transient expression of a green fluorescent protein fusion indicated that the LACS9 protein is localized in the plastid envelope. A T-DNA knockout mutant (lacs9-1) was identified by reverse genetics and these mutant plants were indistinguishable from wild type in growth and appearance. Analysis of leaf lipids provided no evidence for compromised export of acyl groups from chloroplasts. However, direct assays demonstrated that lacs9-1 plants contained only 10% of the chloroplast long-chain ACS activity found for wild type. The residual long-chain ACS activity in mutant chloroplasts was comparable with calculated rates of fatty acid synthesis. Although another isozyme contributes to the activation of fatty acids during their export from the chloroplast, LACS9 is a major chloroplast ACS.
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Affiliation(s)
- Judy A Schnurr
- Institute of Biological Chemistry, Washington State University, P.O. Box 646340, Pullman, Washington 99164-6340, USA
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Behal RH, Lin M, Back S, Oliver DJ. Role of acetyl-coenzyme A synthetase in leaves of Arabidopsis thaliana. Arch Biochem Biophys 2002; 402:259-67. [PMID: 12051672 DOI: 10.1016/s0003-9861(02)00086-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Acetyl-coenzyme A synthetase (ACS) is a plastidic enzyme that forms acetyl-coenzyme A (acetyl-CoA) from acetate and coenzyme A using the energy from ATP. Traditionally it has been thought to be the major source for the production of acetyl-CoA destined for fatty acid formation. Recent work suggested that the accumulation of lipids in developing Arabidopsis seeds was more closely correlated with the expression of pyruvate dehydrogenase complex than with the expression of ACS, suggesting that most of the carbon for fatty acid formation in the plastids of seeds comes from pyruvate rather than from acetate. To explore the role of this enzyme, Arabidopsis plants with altered amounts of ACS were generated by overexpressing its cDNA in either the sense or the antisense configuration. The resulting plants had in vitro enzyme activities that ranged from about 5% to over 400% of wild-type levels. The rate of [1-14C]acetate conversion into fatty acids was closely related to the in vitro ACS activity, showing that the amount of enzyme clearly limited the capacity of leaves to convert exogenous acetate to fatty acids. There was, however, no relationship between the ACS level and the capacity of the plants to incorporate 14CO2 into 14C-labeled fatty acids. These data strongly support the idea that, although plants can convert acetate into fatty acids, relatively little carbon moves through this pathway under normal conditions.
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Affiliation(s)
- Robert H Behal
- Department of Botany, Iowa State University, Ames, Iowa 50011, USA
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Bonaventure G, Ohlrogge JB. Differential regulation of mRNA levels of acyl carrier protein isoforms in Arabidopsis. PLANT PHYSIOLOGY 2002; 128:223-235. [PMID: 11788768 DOI: 10.1104/pp.010397] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
All higher plants express several different acyl carrier protein (ACP) isoforms in a tissue-specific manner. We provide evidence that expression of mRNA for the most abundant ACP isoform in Arabidopsis leaves (ACP4) is increased severalfold by light, whereas mRNA levels for ACP isoforms 2 and 3 are independent of light. The presence of GATA-like motifs in the upstream region of the Acl1.4 gene (encoding for ACP4) and the similarity in light-mediated induction to ferredoxin-A mRNA suggests a direct role of light in Acl1.4 gene activation. Polyribosomal analysis indicated that light also affects the association of ACP transcripts with polysomes, similarly to mRNAs encoding ferredoxin-A. ACP2, ACP3, and ACP4 mRNA levels were also examined in Arabidopsis cell suspension culture and were found to be differentially controlled by metabolic and/or growth derived signals. Comparison of 5'-untranslated regions (UTRs) of ACP mRNAs of diverse plant species revealed two motifs that have been conserved during evolution, a CTCCGCC box and C-T-rich sequences. Fusions of the 5'-UTR sequences of ACP1 and ACP2 to luciferase and expression in transgenic plants indicated that the ACP1 leader contributes to preferential expression in seeds, whereas the ACP2 5'-UTR favored expression in roots. The deletion of 58 bp containing the conserved motifs of the ACP1 5'-UTR resulted in 10- to 20-fold lower gene expression in leaf and seed tissues of transgenic Arabidopsis plants.
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Affiliation(s)
- Gustavo Bonaventure
- Genetics Program, Michigan State University, East Lansing, Michigan 48824, USA
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Soll J, Roughan G. Acyl-acyl carrier protein and pool sizes during steady-state fatty acid synthesis by isolated spinach chloroplasts. FEBS Lett 2001. [DOI: 10.1016/0014-5793(82)80732-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Laing W, Roughan P. Activation of spinach chloroplast acetyl-coenzyme A carboxylase by coenzyme A. FEBS Lett 2001. [DOI: 10.1016/0014-5793(82)80668-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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