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Wrobel TJ, Brilhaus D, Stefanski A, Stühler K, Weber APM, Linka N. Mapping the castor bean endosperm proteome revealed a metabolic interaction between plastid, mitochondria, and peroxisomes to optimize seedling growth. FRONTIERS IN PLANT SCIENCE 2023; 14:1182105. [PMID: 37868318 PMCID: PMC10588648 DOI: 10.3389/fpls.2023.1182105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 08/07/2023] [Indexed: 10/24/2023]
Abstract
In this work, we studied castor-oil plant Ricinus communis as a classical system for endosperm reserve breakdown. The seeds of castor beans consist of a centrally located embryo with the two thin cotyledons surrounded by the endosperm. The endosperm functions as major storage tissue and is packed with nutritional reserves, such as oil, proteins, and starch. Upon germination, mobilization of the storage reserves requires inter-organellar interplay of plastids, mitochondria, and peroxisomes to optimize growth for the developing seedling. To understand their metabolic interactions, we performed a large-scale organellar proteomic study on castor bean endosperm. Organelles from endosperm of etiolated seedlings were isolated and subjected to liquid chromatography-tandem mass spectrometry (LC-MS/MS). Computer-assisted deconvolution algorithms were applied to reliably assign the identified proteins to their correct subcellular localization and to determine the abundance of the different organelles in the heterogeneous protein samples. The data obtained were used to build a comprehensive metabolic model for plastids, mitochondria, and peroxisomes during storage reserve mobilization in castor bean endosperm.
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Affiliation(s)
- Thomas J. Wrobel
- Institute of Plant Biochemistry and Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, Düsseldorf, Germany
| | - Dominik Brilhaus
- Institute of Plant Biochemistry and Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, Düsseldorf, Germany
| | - Anja Stefanski
- Molecular Proteomics Laboratory, Biologisch-Medizinisches Forschungszentrum (BMFZ), Universitätsklinikum, Düsseldorf, Germany
| | - Kai Stühler
- Molecular Proteomics Laboratory, Biologisch-Medizinisches Forschungszentrum (BMFZ), Universitätsklinikum, Düsseldorf, Germany
| | - Andreas P. M. Weber
- Institute of Plant Biochemistry and Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, Düsseldorf, Germany
| | - Nicole Linka
- Institute of Plant Biochemistry and Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, Düsseldorf, Germany
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Turesson H, Marttila S, Gustavsson KE, Hofvander P, Olsson ME, Bülow L, Stymne S, Carlsson AS. Characterization of oil and starch accumulation in tubers of Cyperus esculentus var. sativus (Cyperaceae): A novel model system to study oil reserves in nonseed tissues. AMERICAN JOURNAL OF BOTANY 2010; 97:1884-93. [PMID: 21616827 DOI: 10.3732/ajb.1000200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
PREMISE OF THE STUDY Storage oil (triacylglycerol) accumulates in tissues such as the embryo and endosperm of seeds and the fruit mesocarp, but seldom in underground organs. As a rare exception, cultivated variants of yellow nutsedge (Cyperus esculentus) contain high amounts of both oil and starch in the mature tubers. • METHODS Biochemical analyses and light and electron microscopy were used to study the accumulation patterns of storage nutrients in developing nutsedge tubers. • KEY RESULTS During the initial phase of tuber development, the conducting rhizome tissue is transformed into a storage compartment, then massive storage reserves accumulate in the tuber. At the beginning of tuber development, a large sugar load coincided with the onset of starch accumulation. Oil accumulation started later, concomitant with a substantial drop in the sugar content. Initially, oil accumulated at a lower rate compared to starch, but the rate later increased; after 6 wk, oil made up 24% of tuber dry mass, while starch made up 32%. Protein concentration changed only a small amount throughout this development. Oil and starch accumulated in the same cells throughout the tubers in a sequential fashion during tuber development. • CONCLUSIONS The developmental pattern in the build up of storage nutrients in the tubers highlights nutsedge as a novel model plant, having potential to significantly widen our understanding on how synthesis of storage reserves, and in particular oils, is regulated and directed in nonseed tissues such as tubers and roots.
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Affiliation(s)
- Helle Turesson
- Department of Plant Breeding and Biotechnology, Swedish University of Agricultural Sciences, P.O. Box 101, SE - 23053 Alnarp, Sweden
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4
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Cagliari A, Margis-Pinheiro M, Loss G, Mastroberti AA, de Araujo Mariath JE, Margis R. Identification and expression analysis of castor bean (Ricinus communis) genes encoding enzymes from the triacylglycerol biosynthesis pathway. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2010; 179:499-509. [PMID: 21802608 DOI: 10.1016/j.plantsci.2010.07.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 07/18/2010] [Accepted: 07/24/2010] [Indexed: 05/12/2023]
Abstract
Castor bean (Ricinus communis) oil contains ricinoleic acid-rich triacylglycerols (TAGs). As a result of its physical and chemical properties, castor oil and its derivatives are used for numerous bio-based products. In this study, we survey the Castor Bean Genome Database to report the identification of TAG biosynthesis genes. A set of 26 genes encoding six distinct classes of enzymes involved in TAGs biosynthesis were identified. In silico characterization and sequence analysis allowed the identification of plastidic isoforms of glycerol-3-phosphate acyltransferase and lysophosphatidate acyltransferase enzyme families, involved in the prokaryotic lipid biosynthesis pathway, that form a cluster apart from the cytoplasmic isoforms, involved in the eukaryotic pathway. In addition, two distinct membrane bound diacylglycerol acyltransferase enzymes were identified. Quantitative expression pattern analyses demonstrated variations in gene expressions during castor seed development. A tendency of maximum expression level at the middle of seed development was observed. Our results represent snapshots of global transcriptional activities of genes encompassing six enzyme families involved in castor bean TAG biosynthesis that are present during seed development. These genes represent potential targets for biotechnological approaches to produce nutritionally and industrially desirable oils.
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Affiliation(s)
- Alexandro Cagliari
- Departamento de Genética, Universidade Federal do Rio Grande do Sul, Brazil.
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5
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Ekman A, Hayden DM, Dehesh K, Bülow L, Stymne S. Carbon partitioning between oil and carbohydrates in developing oat (Avena sativa L.) seeds. JOURNAL OF EXPERIMENTAL BOTANY 2008; 59:4247-57. [PMID: 19036843 PMCID: PMC2639027 DOI: 10.1093/jxb/ern266] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 10/03/2008] [Accepted: 10/06/2008] [Indexed: 05/19/2023]
Abstract
Cereals accumulate starch in the endosperm as their major energy reserve in the grain. In most cereals the embryo, scutellum, and aleurone layer are high in oil, but these tissues constitute a very small part of the total seed weight. However, in oat (Avena sativa L.) most of the oil in kernels is deposited in the same endosperm cells that accumulate starch. Thus oat endosperm is a desirable model system to study the metabolic switches responsible for carbon partitioning between oil and starch synthesis. A prerequisite for such investigations is the development of an experimental system for oat that allows for metabolic flux analysis using stable and radioactive isotope labelling. An in vitro liquid culture system, developed for detached oat panicles and optimized to mimic kernel composition during different developmental stages in planta, is presented here. This system was subsequently used in analyses of carbon partitioning between lipids and carbohydrates by the administration of 14C-labelled sucrose to two cultivars having different amounts of kernel oil. The data presented in this study clearly show that a higher amount of oil in the high-oil cultivar compared with the medium-oil cultivar was due to a higher proportion of carbon partitioning into oil during seed filling, predominantly at the earlier stages of kernel development.
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Affiliation(s)
- Asa Ekman
- Department of Plant Breeding and Biotechnology, Swedish University of Agricultural Sciences, P.O. Box 101, SE-23053 Alnarp, Sweden.
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Simkin AJ, Qian T, Caillet V, Michoux F, Ben Amor M, Lin C, Tanksley S, McCarthy J. Oleosin gene family of Coffea canephora: quantitative expression analysis of five oleosin genes in developing and germinating coffee grain. JOURNAL OF PLANT PHYSIOLOGY 2006; 163:691-708. [PMID: 16442665 DOI: 10.1016/j.jplph.2005.11.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2005] [Accepted: 11/02/2005] [Indexed: 05/06/2023]
Abstract
Coffee grains have an oil content between 10% and 16%, with these values associated with Coffea canephora (robusta) and C. arabica (arabica), respectively. As the majority of the oil stored in oil seeds is contained in specific structures called oil bodies, we were interested in determining whether there are any differences in the expression of the main oil body proteins, the oleosins, between the robusta and arabica varieties. Here, we present the isolation, characterization and quantitative expression analysis of six cDNAs representing five genes of the coffee oleosin family (CcOLE-1 to CcOLE-5) and one gene of the steroleosin family (CcSTO-1). Each coffee oleosin cDNA encodes for the signature structure for oleosins, a long hydrophobic central sequence containing a proline KNOT motif. Sequence analysis also indicates that the C-terminal domain of CcOLE-1, CcOLE-3 and CcOLE-5 contain an 18-residue sequence typical of H-form oleosins. Quantitative RT-PCR showed that the transcripts of all five oleosins were predominantly expressed during grain maturation in robusta and arabica grain, with CcOLE-1 and CcOLE-2 being more highly expressed. While the relative expression levels of the five oleosins were similar for robusta and arabica, significant differences in the absolute levels of expression were found between the two species. Quantitative analysis of oleosin transcripts in germinating arabica grain generally showed that the levels of these transcripts were lower in the grain after drying, and then further decreased during germination, except for a small spike of expression for CcOLE-2 early in germination. In contrast, the levels of CcSTO-1 transcripts remained relatively constant during germination, in agreement with suggestions that this protein is actively involved in the process of oil body turnover. Finally, we discuss the implications of the coffee oleosin expression data presented relative to the predicted roles for the different coffee oleosins during development and germination.
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Affiliation(s)
- Andrew J Simkin
- Centre de Recherche Nestlé, 101 Av. Gustave Eiffel, Notre Dame d'Oé, BP 49716-37097 Tours, France
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7
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Manz B, Müller K, Kucera B, Volke F, Leubner-Metzger G. Water uptake and distribution in germinating tobacco seeds investigated in vivo by nuclear magnetic resonance imaging. PLANT PHYSIOLOGY 2005; 138:1538-51. [PMID: 15980194 PMCID: PMC1176424 DOI: 10.1104/pp.105.061663] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2005] [Revised: 04/14/2005] [Accepted: 04/20/2005] [Indexed: 05/03/2023]
Abstract
The regulation of water uptake of germinating tobacco (Nicotiana tabacum) seeds was studied spatially and temporally by in vivo (1)H-nuclear magnetic resonance (NMR) microimaging and (1)H-magic angle spinning NMR spectroscopy. These nondestructive state-of-the-art methods showed that water distribution in the water uptake phases II and III is inhomogeneous. The micropylar seed end is the major entry point of water. The micropylar endosperm and the radicle show the highest hydration. Germination of tobacco follows a distinct pattern of events: rupture of the testa is followed by rupture of the endosperm. Abscisic acid (ABA) specifically inhibits endosperm rupture and phase III water uptake, but does not alter the spatial and temporal pattern of phase I and II water uptake. Testa rupture was associated with an increase in water uptake due to initial embryo elongation, which was not inhibited by ABA. Overexpression of beta-1,3-glucanase in the seed-covering layers of transgenic tobacco seeds did not alter the moisture sorption isotherms or the spatial pattern of water uptake during imbibition, but partially reverted the ABA inhibition of phase III water uptake and of endosperm rupture. In vivo (13)C-magic angle spinning NMR spectroscopy showed that seed oil mobilization is not inhibited by ABA. ABA therefore does not inhibit germination by preventing oil mobilization or by decreasing the water-holding capacity of the micropylar endosperm and the radicle. Our results support the proposal that different seed tissues and organs hydrate at different extents and that the micropylar endosperm region of tobacco acts as a water reservoir for the embryo.
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Affiliation(s)
- Bertram Manz
- Fraunhofer-Institut für Biomedizinische Technik, Arbeitsgruppe Magnetische Resonanz, D-66386 St. Ingbert, Germany
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8
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Gallardo K, Job C, Groot SPC, Puype M, Demol H, Vandekerckhove J, Job D. Proteomics of Arabidopsis seed germination. A comparative study of wild-type and gibberellin-deficient seeds. PLANT PHYSIOLOGY 2002; 129:823-37. [PMID: 12068122 PMCID: PMC161704 DOI: 10.1104/pp.002816] [Citation(s) in RCA: 184] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2002] [Revised: 02/13/2002] [Accepted: 03/07/2002] [Indexed: 05/18/2023]
Abstract
We examined the role of gibberellins (GAs) in germination of Arabidopsis seeds by a proteomic approach. For that purpose, we used two systems. The first system consisted of seeds of the GA-deficient ga1 mutant, and the second corresponded to wild-type seeds incubated in paclobutrazol, a specific GA biosynthesis inhibitor. With both systems, radicle protrusion was strictly dependent on exogenous GAs. The proteomic analysis indicated that GAs do not participate in many processes involved in germination sensu stricto (prior to radicle protrusion), as, for example, the initial mobilization of seed protein and lipid reserves. Out of 46 protein changes detected during germination sensu stricto (1 d of incubation on water), only one, corresponding to the cytoskeleton component alpha-2,4 tubulin, appeared to depend on the action of GAs. An increase in this protein spot was noted for the wild-type seeds but not for the ga1 seeds incubated for 1 d on water. In contrast, GAs appeared to be involved, directly or indirectly, in controlling the abundance of several proteins associated with radicle protrusion. This is the case for two isoforms of S-adenosyl-methionine (Ado-Met) synthetase, which catalyzes the formation of Ado-Met from Met and ATP. Owing to the housekeeping functions of Ado-Met, this event is presumably required for germination and seedling establishment, and might represent a major metabolic control of seedling establishment. GAs can also play a role in controlling the abundance of a beta-glucosidase, which might be involved in the embryo cell wall loosening needed for cell elongation and radicle extension.
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Affiliation(s)
- Karine Gallardo
- Laboratoire Mixte Centre National de la Recherche Scientifique-Institut National de la Recherche Agronomique-Aventis, Aventis CropScience, B.P. 9163 F69263 Lyon cedex 09, France
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9
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Abstract
Water uptake is the trigger for germination and growth. It is a triphasic process, involving a rapid rehydration of the endosperm, a steady uptake during a period of active metabolism and finally, a rapid uptake during development of the root system. The water spin lattice relaxation time (T
1
) of the germinating seed of the castor bean (
Ricinus communis zanzibariensis
) apparently decreases with increasing water content. This anomalous behaviour is resolved when the recovery process is analysed as two components: each component shows the expected dependence on water content but the proportion of the faster relaxing component increases during development, NMR microscopy is used to investigate the location of these water compartments and to follow the anatomical changes which occur during the germination and early growth processes.
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Dommes J, Northcote DH. The action of exogenous abscisic and gibberellic acids on gene expression in germinating castor beans. PLANTA 1985; 165:513-521. [PMID: 24241225 DOI: 10.1007/bf00398097] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/1984] [Accepted: 02/19/1985] [Indexed: 06/02/2023]
Abstract
Exogenously applied abscisic acid inhibits isocitrate-lyase activity of the endosperm during germination of castor-bean seeds. Amounts of isocitrate-lyase mRNA have been estimated by immunoprecipitation of in-vitro-translated polypeptide products. Exogenous abscisic acid leads to an inhibition of isocitrate lyase-mRNA accumulation. A large proportion of this effect of the growth factor may be accounted for by its action in inhibiting the overall accumulation of ribosomal RNA and total mRNA. However, the effect of abscisic acid on protein synthesis is not general, as the production of some mRNAs was stimulated. The major mRNA stored in the dry seed, coding for a 25600-Mr polypeptide that normally disappears within the first 12 h of germination, exhibited high levels in abscisic-acid-treated endosperms throughout the germination period. Three complementary DNA clones, of which two clones are complementary to isocitrate lyase, have been used to measure levels of transcripts during seed germination. The accumulation of both transcripts was inhibited by exogenous abscisic acid. The data strongly indicate that the action of abscisic acid on isocitrate lyase synthesis is either to inhibit the transcription, or to increase the transcript turnover. Exogenous gibberellic acid is able to counteract the inhibitory effects of abscisic acid.
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Affiliation(s)
- J Dommes
- Department of Biochemistry, University of Cambridge, Tennis Court Road, CB2 1QW, Cambridge, UK
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11
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Martin C, Beeching JR, Northcote DH. Changes in levels of transcripts in endosperms of castor beans treated with exogenous gibberellic acid. PLANTA 1984; 162:68-76. [PMID: 24253949 DOI: 10.1007/bf00397423] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/1984] [Accepted: 03/28/1984] [Indexed: 06/02/2023]
Abstract
A complementary-DNA library to mRNA from castor-bean endosperm has been prepared. Three clones have been examined in detail. One of these is complementary to isocitrate-lyase mRNA. The other two clones code for proteins with M r , 42000 and 38000. All three clones have been used to measure levels of transcripts during seed germination. The three transcripts all increased during germination and the rate of their appearance is stimulated by exogenous GA3. The data strongly support the view that the action of GA3 in these seeds is to stimulate non-specifically the rate of transcription and, in turn, protein synthesis. Possible mechanisms for the action of the growth regulator are discussed.
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Affiliation(s)
- C Martin
- Department of Biochemistry, University of Cambridge, Tennis Court Road, CB2 1QW, Cambridge, UK
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12
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Martin C, Northcote DH. The action of exogenous gibberellic acid on polysome formation and translation of mRNA in germinating castor-bean seeds. PLANTA 1983; 158:16-26. [PMID: 24264443 DOI: 10.1007/bf00395398] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/1982] [Accepted: 02/01/1983] [Indexed: 06/02/2023]
Abstract
The amount of protein synthesis in germinating castor-bean seeds has been estimated by the quantitative and qualitative exmainatin of polysomes from the seeds in the presence and absence of gibberellic acid (GA3). Careful optimisation of polysome extraction procedures was required to minimise the ribonuclease activity in the extracts. Ribonuclease activity in seed extracts increased fourfold over the first 5 d of germination. Gibberellic acid stimulated polysome formation about twofold during the first 4 d of germination. It also stimulated the amount of mRNA associated with polysomes by about twofold during the first 3 d of germination. Between days 1 and 5 of germination, polysome formation was primarily limited by mRNA availability. During the period 0-24 h, polysome formation was independent of mRNA levles. The increase in enzyme activities stimulated by GA3 was probably the result of an increase in the amount of cellular mRNA. No evidence was obtained for an action of GA3 on translation other than on the increased production of RNA. Examination of the recruitment of isocitrate-lyase mRNA into polysomes showed that GA3 did not specifically stimulate production of this enzyme.
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Affiliation(s)
- C Martin
- Department of Biochemistry, University of Cambridge, Tennis Court Road, CB2 1QW, Cambridge, UK
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13
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Martin C, Northcote DH. The action of exogenous gibberellic acid on protein and mRNA in germinating castor bean seeds. PLANTA 1982; 154:168-173. [PMID: 24275979 DOI: 10.1007/bf00387912] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/1981] [Accepted: 12/01/1981] [Indexed: 06/02/2023]
Abstract
Gibberellic acid (GA3) stimulates water uptake in castor beans and increases the activity of certain enzymes associated with lipid mobilisation.The effect of the GA3 on the enzymes is possibly due to a general effect of the growth substance on protein synthesis. Gibberellic acid advanced the appearance of rRNA and poly (A(+))RNA in castor bean endosperms without specifically stimulating the synthesis of particular mRNA species. Thus these increased levels of mRNA and rRNA may act synergistically to affect the rate of a predetermined pattern of protein synthesis.
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Affiliation(s)
- C Martin
- Department of Biochemistry, University of Cambridge, Tennis Court Road, CB2 1QW, Cambridge, UK
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14
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Wellburn A. Bioenergetic and Ultrastructural Changes Associated with Chloroplast Development. ACTA ACUST UNITED AC 1982. [DOI: 10.1016/s0074-7696(08)60369-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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15
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González E, Delsol MA. Induction of glyconeogenic enzymes by gibberellin a(3) in endosperm of castor bean seedlings. PLANT PHYSIOLOGY 1981; 67:550-4. [PMID: 16661712 PMCID: PMC425723 DOI: 10.1104/pp.67.3.550] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Seedlings of castor bean (Ricinus communis cv. Hale) were exposed to gibberellin A(3) (GA(3)) (100 micromolar) for periods up to 20 hours. Endosperm homogenates were fractionated on linear sucrose gradients and enzymes in mitochondria, glyoxysome, and cytosol fractions were assayed. Gibberellin treatment resulted in increases in the activities of enzymes in all three compartments. There were also enzymes in all three compartments which were not affected by exogenous applications of GA(3). The isozymes of l-asparate-alpha-ketoglutarate aminotransferase in both mitochondria and glyoxysomes were induced coordinately, whereas the isozymes of citrate synthase and malate dehydrogenase were not. All gluconeogenic enzymes in glyoxysomes are induced by GA(3). With the exception of the mitochondrial malate dehydrogenase isozyme, all enzymes of the tricarboxylic acid cycle believed to participate in glyconeogenesis were increased. The cytosolic enzymes malate dehydrogenase, phosphoenolpyruvate carboxykinase, and fructose bisphosphatase were induced, but the levels of pyruvate kinase and enolase were not affected by GA(3) treatment.
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Affiliation(s)
- E González
- Department of Biology, University of California, Los Angeles, California 90024
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16
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Halmer P, Bewley JD. Mannanase production by the lettuce endosperm : Control by the embryo. PLANTA 1979; 144:333-340. [PMID: 24407322 DOI: 10.1007/bf00391576] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/1978] [Accepted: 10/18/1978] [Indexed: 06/03/2023]
Abstract
Endo-β-mannanase (EC 3.2.1.78) is produced and secreted by the cells of the endosperm of lettuce (lactuca sativa L.) "seeds" (achenes). In imbibed intact seeds, production is prevented by inhibitors. If the endosperm is incubated alone, these inhibitors can be removed by leaching, allowing mannanase production. Abscisic acid, a component of lettuce seeds, inhibits the production of mannanase in the isolated endosperm, and may be involved in regulation of mannanase production in intact seeds. During germination the inhibition is removed, beginning 4-8 h after red-light irradiation, which was given 4 h from sowing. The cotyledons participate in this process, and are controlled by events occuring in the axis within 4 h from red-light irradiation. This control by the axis apparently depends on the exchange of diffusible substances. Both benzyladenine and gibberellic acid can replace the influence of the axis if the latter is removed, and may therefore be involved in the control by the axis of the rest of the seed.
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Affiliation(s)
- P Halmer
- Department of Biology, University of Calgary, T2N 1N4, Calgary, Alta, Canada
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17
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Bajracharya D, Schopfer P. Effect of light on the development of glyoxysomal functions in the cotyledons of mustard (Sinapis alba L.) seedlings. PLANTA 1979; 145:181-186. [PMID: 24317674 DOI: 10.1007/bf00388715] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/1978] [Accepted: 12/01/1978] [Indexed: 06/02/2023]
Abstract
The degradation of storage fat in the cotyledons of mustard seedlings is unaffected by phytochrome and photosynthesis (irradiation with continuous red or far-red light from sowing of the seeds) although light imposes a strong constraint on the translocation of organic matter from the cotyledons into the seedling axis. Likewise, the development and disappearance of glyoxysomal enzyme activities (isocitrate lyase, malate synthase, citrate synthase) takes place independently of light. It is concluded that the mobilization of storage fat (fat→carbohydrate transformation) is independent of photomorphogenesis. The surplus of carbohydrate produced from fat in the light seems to be converted to starch grains in the plastids, which function as a secondary storage pool in the cotyledons.
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Affiliation(s)
- D Bajracharya
- Biologisches Institut II der Universität Freiburg, Schänzlestraße 1, D-7800, Freiburg, Federal Republic of Germany
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18
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González E. Effect of gibberellin a(3) on the endoplasmic reticulum and on the formation of glyoxysomes in the endosperm of germinating castor bean. PLANT PHYSIOLOGY 1978; 62:449-53. [PMID: 16660535 PMCID: PMC1092144 DOI: 10.1104/pp.62.3.449] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Seedlings of castor bean (Ricinus communis cv. Hale) were exposed to a range of concentrations of gibberellin A(3) (GA(3)). Treatments for 20 hours with GA(3) concentrations of 0.5 muM or higher resulted in increased levels of NADH-cytochrome c reductase, phosphorylcholine glyceride transferase, and malate synthase in endoplasmic reticulum (ER) isolated from endosperm on linear sucrose gradients. GA(3) treatment also resulted in increased RNA associated with ER. Malate synthase and catalase in crude homogenates were enhanced by 1 to 100 muM GA(3) concentrations. Isocitrate lyase, citrate synthase, malate synthase, catalase, and glycolate oxidase in isolated glyoxysomes were enhanced by 60, 20, 18, 40, and 28%, respectively, over controls. Treatment with abscisic acid led to decreased levels of glyoxysomal enzymes and reduced glyoxysomal protein. The effect of GA(3) and abscisic acid on the specific activities of glyoxysomes of different densities suggests that GA(3) influences enzyme levels and glyoxysome assembly.
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Affiliation(s)
- E González
- Department of Biology, University of California, Los Angeles, California 90024
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19
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Donaldson RP. Accumulation of free ricinoleic Acid in germinating castor bean endosperm. PLANT PHYSIOLOGY 1977; 59:1064-6. [PMID: 16659994 PMCID: PMC542507 DOI: 10.1104/pp.59.6.1064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Lipids from the endosperm of germinating castor bean (Ricinus communis var. Hale) were separated by thin layer chromatography and quantitated by gas chromatography. During the later stages of lipid breakdown (4-6 days germination at 30 C), several lipid classes were found in addition to the storage triglycerides, which are triricinoleins for the most part. One was identified as free ricinoleic acid, the proportion of which increased as germination progressed. After 6 days germination, ricinoleic acid comprised more than 30% of the total lipid. The appearance of this fatty acid implies that lipase activity (lipolysis) is not strictly coordinated with beta oxidation in this tissue.
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Affiliation(s)
- R P Donaldson
- Thimann Laboratories, University of California, Santa Cruz, California 95064
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Donaldson RP, Beevers H. Lipid composition of organelles from germinating castor bean endosperm. PLANT PHYSIOLOGY 1977; 59:259-63. [PMID: 16659829 PMCID: PMC542377 DOI: 10.1104/pp.59.2.259] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Glyoxysome, endoplasmic reticulum, mitochondria, and proplastid fractions were isolated from endosperm of castor beans (Ricinus communis) germinated for 5 days at 30 C. Samples from sucrose density gradients were diluted with 0.15 m KCI and the membranes pelleted. Lipid extracts of these membranes were analyzed for phosphoglyceride, acyl lipid, and sterol content. The endoplasmic reticulum contains 1.24 mumol of phosphoglyceride per mg of protein; the mitochondria, 0.65 mumol/mg; and the glyoxysome membranes, 0.55 mumol/mg. Phosphatidyl choline and phosphatidyl ethanolamine are the most abundant lipids in all membranes studied, accounting for 70% or more of the lipid phosphorus and 50% or more of the fatty acid. Glyoxysome membranes and endoplasmic reticulum also contain phosphatidyl inositol (respectively, 9 and 17% of the lipid phosphorus) and free fatty acids (13% of the total fatty acid in each). Compared with other organelles, mitochondrial membranes have more phosphatidyl ethanolamine relative to phosphatidyl choline and are characterized by the presence of cardiolipin, in which 80% of the fatty acid is linoleate. The relative amounts of linoleate, palmitate, oleate, stearate, and linolenate in each of the phosphotoglycerides are constant regardless of the membrane source. Stimasgasterol and beta-sitosterol are present in the membranes (1-9 nmol each/mg protein).The data provide further evidence that glyoxysome membranes are derived from the endoplasmic reticulum but at the same time indicate some differentiation.
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Affiliation(s)
- R P Donaldson
- Thimann Laboratories, University of California, Santa Cruz, California 95064
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Marriott KM, Northcote DH. The induction of enzyme activity in the endosperm of germinating castor-bean seeds. Biochem J 1975; 152:65-70. [PMID: 1212227 PMCID: PMC1172440 DOI: 10.1042/bj1520065] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Endosperm extracts were prepared at various times during germination from intact castor-bean seeds and from seeds from which the embryos had been removed. The sterilized seeds were incubated either on solid water agar or on agar containing 0.3 mM-gibberellic acid. 2. Isocitrate lyase and 3-hydroxyacyl-CoA dehydrogenase had very low activities in the mature seeds, but increased 44-fold and 27-fold respectively during germination. In contrast, the extracts of mature seeds had considerable acid and alkaline lipase activity and this only increased two- to three-fold during the incubation period. 3. Incubation of the seeds with gibberellic acid accelerated the rate of appearance of isocitrate lyase and 3-hydroxyacyl-CoA dehydrogenase. It also increased the total activity attained. However, the application of hormone had, in comparison, little effect on the development of lipase activity. 4. The removal of the embryo had little influence on the development of enzyme activity in the endosperm tissue; only with isocitrate lyase was a decrease in activity observed in the absence of the embryo.
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