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Wieloch T, Sharkey TD, Werner RA, Schleucher J. Intramolecular carbon isotope signals reflect metabolite allocation in plants. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2558-2575. [PMID: 35084456 PMCID: PMC9015809 DOI: 10.1093/jxb/erac028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 01/24/2022] [Indexed: 05/26/2023]
Abstract
Stable isotopes at natural abundance are key tools to study physiological processes occurring outside the temporal scope of manipulation and monitoring experiments. Whole-molecule carbon isotope ratios (13C/12C) enable assessments of plant carbon uptake yet conceal information about carbon allocation. Here, we identify an intramolecular 13C/12C signal at tree-ring glucose C-5 and C-6 and develop experimentally testable theories on its origin. More specifically, we assess the potential of processes within C3 metabolism for signal introduction based (inter alia) on constraints on signal propagation posed by metabolic networks. We propose that the intramolecular signal reports carbon allocation into major metabolic pathways in actively photosynthesizing leaf cells including the anaplerotic, shikimate, and non-mevalonate pathway. We support our theoretical framework by linking it to previously reported whole-molecule 13C/12C increases in cellulose of ozone-treated Betula pendula and a highly significant relationship between the intramolecular signal and tropospheric ozone concentration. Our theory postulates a pronounced preference for leaf cytosolic triose-phosphate isomerase to catalyse the forward reaction in vivo (dihydroxyacetone phosphate to glyceraldehyde 3-phosphate). In conclusion, intramolecular 13C/12C analysis resolves information about carbon uptake and allocation enabling more comprehensive assessments of carbon metabolism than whole-molecule 13C/12C analysis.
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Affiliation(s)
- Thomas Wieloch
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87 Umeå, Sweden
| | - Thomas David Sharkey
- MSU-DOE Plant Research Laboratory, Plant Resilience Institute, and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Roland Anton Werner
- Department of Environmental Systems Science, ETH Zürich, Universitätstrasse 2, 8092 Zürich, Switzerland
| | - Jürgen Schleucher
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87 Umeå, Sweden
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2
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Xu Q, Niu SC, Li KL, Zheng PJ, Zhang XJ, Jia Y, Liu Y, Niu YX, Yu LH, Chen DF, Zhang GQ. Chromosome-Scale Assembly of the Dendrobium nobile Genome Provides Insights Into the Molecular Mechanism of the Biosynthesis of the Medicinal Active Ingredient of Dendrobium. Front Genet 2022; 13:844622. [PMID: 35299950 PMCID: PMC8921531 DOI: 10.3389/fgene.2022.844622] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 02/11/2022] [Indexed: 01/07/2023] Open
Abstract
Orchids constitute approximately 10% of flowering plant species. However, only about 10 orchid genomes have been published. Metabolites are the main way through which orchids respond to their environment. Dendrobium nobile, belonging to Dendrobium, the second largest genus in Orchidaceae, has high ornamental, medicinal, and ecological value. D. nobile is the source of many popular horticultural varieties. Among the Dendrobium species, D. nobile has the highest amount of dendrobine, which is regarded as one of the criteria for evaluating medicinal quality. Due to lack of data and analysis at the genomic level, the biosynthesis pathways of dendrobine and other related medicinal ingredients in D. nobile are unknown. In this paper, we report a chromosome-scale reference genome of D. nobile to facilitate the investigation of its genomic characteristics for comparison with other Dendrobium species. The assembled genome size of D. nobile was 1.19 Gb. Of the sequences, 99.45% were anchored to 19 chromosomes. Furthermore, we identified differences in gene number and gene expression patterns compared with two other Dendrobium species by integrating whole-genome sequencing and transcriptomic analysis [e.g., genes in the polysaccharide biosynthesis pathway and upstream of the alkaloid (dendrobine) biosynthesis pathway]. Differences in the TPS and CYP450 gene families were also found among orchid species. All the above differences might contribute to the species-specific medicinal ingredient biosynthesis pathways. The metabolic pathway-related analysis will provide further insight into orchid responses to the environment. Additionally, the reference genome will provide important insights for further molecular elucidation of the medicinal active ingredients of Dendrobium and enhance the understanding of orchid evolution.
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Affiliation(s)
- Qing Xu
- GMU-GIBH Joint School of Life Sciences, Guangzhou Medical University, Guangzhou, China
- *Correspondence: Qing Xu, ; Duan-Fen Chen, ; Guo-Qiang Zhang,
| | - Shan-Ce Niu
- College of Horticulture, Hebei Agricultural University, Baoding, China
- State Key Laboratory of North China Crop Improvement and Regulation, Hebei Agricultural University, Baoding, China
| | - Kang-Li Li
- GMU-GIBH Joint School of Life Sciences, Guangzhou Medical University, Guangzhou, China
| | - Pei-Ji Zheng
- GMU-GIBH Joint School of Life Sciences, Guangzhou Medical University, Guangzhou, China
| | - Xiao-Jing Zhang
- College of Horticulture, Hebei Agricultural University, Baoding, China
| | - Yin Jia
- College of Horticulture, Hebei Agricultural University, Baoding, China
| | - Yang Liu
- College of Horticulture, Hebei Agricultural University, Baoding, China
| | - Yun-Xia Niu
- School of Vocational Education, Tianjin University of Technology and Education, Tianjin, China
| | - Li-Hong Yu
- GMU-GIBH Joint School of Life Sciences, Guangzhou Medical University, Guangzhou, China
| | - Duan-Fen Chen
- College of Horticulture, Hebei Agricultural University, Baoding, China
- *Correspondence: Qing Xu, ; Duan-Fen Chen, ; Guo-Qiang Zhang,
| | - Guo-Qiang Zhang
- GMU-GIBH Joint School of Life Sciences, Guangzhou Medical University, Guangzhou, China
- Laboratory for Orchid Conservation and Utilization, The Orchid Conservation and Research Center of Shenzhen, The National Orchid Conservation Center of China, Shenzhen, China
- *Correspondence: Qing Xu, ; Duan-Fen Chen, ; Guo-Qiang Zhang,
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3
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Ge Y, Chen Y, Li C, Zhao J, Wei M, Li X, Yang S, Mi Y. Effect of sodium nitroprusside treatment on shikimate and phenylpropanoid pathways of apple fruit. Food Chem 2019; 290:263-269. [DOI: 10.1016/j.foodchem.2019.04.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/31/2019] [Accepted: 04/01/2019] [Indexed: 01/23/2023]
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4
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Pratelli R, Pilot G. Regulation of amino acid metabolic enzymes and transporters in plants. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:5535-56. [PMID: 25114014 DOI: 10.1093/jxb/eru320] [Citation(s) in RCA: 185] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Amino acids play several critical roles in plants, from providing the building blocks of proteins to being essential metabolites interacting with many branches of metabolism. They are also important molecules that shuttle organic nitrogen through the plant. Because of this central role in nitrogen metabolism, amino acid biosynthesis, degradation, and transport are tightly regulated to meet demand in response to nitrogen and carbon availability. While much is known about the feedback regulation of the branched biosynthesis pathways by the amino acids themselves, the regulation mechanisms at the transcriptional, post-transcriptional, and protein levels remain to be identified. This review focuses mainly on the current state of our understanding of the regulation of the enzymes and transporters at the transcript level. Current results describing the effect of transcription factors and protein modifications lead to a fragmental picture that hints at multiple, complex levels of regulation that control and coordinate transport and enzyme activities. It also appears that amino acid metabolism, amino acid transport, and stress signal integration can influence each other in a so-far unpredictable fashion.
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Affiliation(s)
- Réjane Pratelli
- Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, VA 24060, USA
| | - Guillaume Pilot
- Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, VA 24060, USA
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5
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Mittelstädt G, Negron L, Schofield LR, Marsh K, Parker EJ. Biochemical and structural characterisation of dehydroquinate synthase from the New Zealand kiwifruit Actinidia chinensis. Arch Biochem Biophys 2013; 537:185-91. [PMID: 23916589 DOI: 10.1016/j.abb.2013.07.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 07/17/2013] [Accepted: 07/18/2013] [Indexed: 11/25/2022]
Abstract
One of the novel aspects of kiwifruit is the presence of a high level of quinic acid which contributes to the flavour of the fruit. Quinic acid metabolism intersects with the shikimate pathway, which is responsible for the de novo biosynthesis of primary and secondary aromatic metabolites. The gene encoding the enzyme which catalyses the second step of the shikimate pathway, dehydroquinate synthase (DHQS), from the New Zealand kiwifruit Actinidia chinensis was identified, cloned and expressed. A. chinensis DHQS was activated by divalent metal ions, and was found to require NAD(+) for catalysis. The protein was crystallised and the structure was solved, revealing a homodimeric protein. Each monomer has a NAD(+) binding site nestled between the distinct N- and C-terminal domains. In contrast to other microbial DHQSs, which show an open conformation in the absence of active site ligands, A. chinensis DHQS adopts a closed conformation. This is the first report of the structure of a DHQS from a plant source.
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Affiliation(s)
- Gerd Mittelstädt
- Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, PO Box 4800, Christchurch 8140, New Zealand
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6
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Maeda H, Dudareva N. The shikimate pathway and aromatic amino Acid biosynthesis in plants. ANNUAL REVIEW OF PLANT BIOLOGY 2012; 63:73-105. [PMID: 22554242 DOI: 10.1146/annurev-arplant-042811-105439] [Citation(s) in RCA: 710] [Impact Index Per Article: 59.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
L-tryptophan, L-phenylalanine, and L-tyrosine are aromatic amino acids (AAAs) that are used for the synthesis of proteins and that in plants also serve as precursors of numerous natural products, such as pigments, alkaloids, hormones, and cell wall components. All three AAAs are derived from the shikimate pathway, to which ≥30% of photosynthetically fixed carbon is directed in vascular plants. Because their biosynthetic pathways have been lost in animal lineages, the AAAs are essential components of the diets of humans, and the enzymes required for their synthesis have been targeted for the development of herbicides. This review highlights recent molecular identification of enzymes of the pathway and summarizes the pathway organization and the transcriptional/posttranscriptional regulation of the AAA biosynthetic network. It also identifies the current limited knowledge of the subcellular compartmentalization and the metabolite transport involved in the plant AAA pathways and discusses metabolic engineering efforts aimed at improving production of the AAA-derived plant natural products.
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Affiliation(s)
- Hiroshi Maeda
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907-2010, USA.
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7
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Almeida J, Quadrana L, Asís R, Setta N, de Godoy F, Bermúdez L, Otaiza SN, Corrêa da Silva JV, Fernie AR, Carrari F, Rossi M. Genetic dissection of vitamin E biosynthesis in tomato. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:3781-98. [PMID: 21527625 PMCID: PMC3134339 DOI: 10.1093/jxb/err055] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 02/07/2011] [Accepted: 02/08/2011] [Indexed: 05/20/2023]
Abstract
Vegetables are critical for human health as they are a source of multiple vitamins including vitamin E (VTE). In plants, the synthesis of VTE compounds, tocopherol and tocotrienol, derives from precursors of the shikimate and methylerythritol phosphate pathways. Quantitative trait loci (QTL) for α-tocopherol content in ripe fruit have previously been determined in an Solanum pennellii tomato introgression line population. In this work, variations of tocopherol isoforms (α, β, γ, and δ) in ripe fruits of these lines were studied. In parallel all tomato genes structurally associated with VTE biosynthesis were identified and mapped. Previously identified VTE QTL on chromosomes 6 and 9 were confirmed whilst novel ones were identified on chromosomes 7 and 8. Integrated analysis at the metabolic, genetic and genomic levels allowed us to propose 16 candidate loci putatively affecting tocopherol content in tomato. A comparative analysis revealed polymorphisms at nucleotide and amino acid levels between Solanum lycopersicum and S. pennellii candidate alleles. Moreover, evolutionary analyses showed the presence of codons evolving under both neutral and positive selection, which may explain the phenotypic differences between species. These data represent an important step in understanding the genetic determinants of VTE natural variation in tomato fruit and as such in the ability to improve the content of this important nutriceutical.
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Affiliation(s)
- Juliana Almeida
- Departamento de Botânica-IB-USP, 277, 05508-900, São Paulo, SP, Brazil
| | - Leandro Quadrana
- Instituto de Biotecnología, Instituto Nacional de Tecnología Agropecuaría (IB-INTA), and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), PO Box 25, B1712WAA Castelar, Argentina (partner group of the Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, Germany)
| | - Ramón Asís
- CIBICI, Facultad de Ciencias Químicas Universidad Nacional de Córdoba, CC 5000, Córdoba, Argentina
| | - Nathalia Setta
- Departamento de Botânica-IB-USP, 277, 05508-900, São Paulo, SP, Brazil
| | - Fabiana de Godoy
- Departamento de Botânica-IB-USP, 277, 05508-900, São Paulo, SP, Brazil
| | - Luisa Bermúdez
- Departamento de Botânica-IB-USP, 277, 05508-900, São Paulo, SP, Brazil
| | - Santiago N. Otaiza
- CIBICI, Facultad de Ciencias Químicas Universidad Nacional de Córdoba, CC 5000, Córdoba, Argentina
| | | | - Alisdair R. Fernie
- Max Planck Institute for Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, Potsdam-Golm, D-14476, Germany
| | - Fernando Carrari
- Instituto de Biotecnología, Instituto Nacional de Tecnología Agropecuaría (IB-INTA), and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), PO Box 25, B1712WAA Castelar, Argentina (partner group of the Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, Germany)
| | - Magdalena Rossi
- Departamento de Botânica-IB-USP, 277, 05508-900, São Paulo, SP, Brazil
- To whom correspondence should be addressed. E-mail: ; E-mail:
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8
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Tzin V, Galili G. The Biosynthetic Pathways for Shikimate and Aromatic Amino Acids in Arabidopsis thaliana. THE ARABIDOPSIS BOOK 2010; 8:e0132. [PMID: 22303258 PMCID: PMC3244902 DOI: 10.1199/tab.0132] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The aromatic amino acids phenylalanine, tyrosine and tryptophan in plants are not only essential components of protein synthesis, but also serve as precursors for a wide range of secondary metabolites that are important for plant growth as well as for human nutrition and health. The aromatic amino acids are synthesized via the shikimate pathway followed by the branched aromatic amino acid metabolic pathway, with chorismate serving as a major branch point intermediate metabolite. Yet, the regulation of their synthesis is still far from being understood. So far, only three enzymes in this pathway, namely, chorismate mutase of phenylalanine and tyrosine synthesis, tryptophan synthase of tryptophan biosynthesis and arogenate dehydratase of phenylalanine biosynthesis, proved experimentally to be allosterically regulated. The major biosynthesis route of phenylalanine in plants occurs via arogenate. Yet, recent studies suggest that an alternative route of phynylalanine biosynthesis via phenylpyruvate may also exist in plants, similarly to many microorganisms. Several transcription factors regulating the expression of genes encoding enzymes of both the shikimate pathway and aromatic amino acid metabolism have also been recently identified in Arabidopsis and other plant species.
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Affiliation(s)
- Vered Tzin
- Department of Plant Sciences, The Weizmann Institute of Science, Rehovot 76100 Israel
| | - Gad Galili
- Department of Plant Sciences, The Weizmann Institute of Science, Rehovot 76100 Israel
- Address correspondence to
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9
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10
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Hamberger B, Ehlting J, Barbazuk B, Douglas CJ. Comparative Genomics of The Shikimate Pathway in Arabidopsis, Populus Trichocarpa and Oryza Sativa: Shikimate Pathway Gene Family Structure and Identification of Candidates for Missing Links in Phenylalanine Biosynthesis. RECENT ADVANCES IN PHYTOCHEMISTRY 2006. [DOI: 10.1016/s0079-9920(06)80038-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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11
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Janzik I, Preiskowski S, Kneifel H. Ozone has dramatic effects on the regulation of the prechorismate pathway in tobacco (Nicotiana tabacum L. cv. Bel W3). PLANTA 2005; 223:20-7. [PMID: 16078071 DOI: 10.1007/s00425-005-0060-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2005] [Accepted: 05/13/2005] [Indexed: 05/03/2023]
Abstract
The accumulation of aromatic secondary metabolites is a well-known element of the plant response to ozone. Most of these metabolites are synthesized via the three aromatic amino acids phenylalanine, tyrosine and tryptophan. Before branching, the biosynthetic pathway to the three amino acids shares seven enzymatic steps, called the prechorismate pathway, catalysed by 3-deoxy-D: -arabino-heptulosonate-7-phosphate (DAHP) synthase [EC 2.5.1.54], 3-dehydroquinate synthase [EC 4.2.3.4], 3-dehydroquinate dehydratase [EC 4.2.1.10]-shikimate 5-dehydrogenase [EC 1.1.1.25], shikimate kinase [EC 2.7.1.71], 5-enolpyruvylshikimate 3-phosphate synthase [EC 2.5.1.19] and chorismate synthase [EC 4.2.3.5]). We have studied the transcript level of these enzymes and the aromatic metabolite profile in the ozone sensitive tobacco cultivar BelW3 (Nicotiana tabacum L. cv Bel W3), when exposed to an acute ozone pulse (160 nl l(-1), 5 h). Specific cDNA-fragments of the corresponding six genes were isolated from tobacco Bel W3 and used as probes for determining the expression of the prechorismate pathway genes. The fully expanded leaves of ozone treated plants, which developed symptoms like necrotic leaf spots and accumulation of aromatic metabolites, showed a clear induction of the shikimate pathway genes; indicating, that this induction is linked to the development of the symptoms. Distinct kinetics and magnitudes were observed in tobacco leaves for the ozone dependent enhanced mRNA accumulation of the aforementioned genes in BelW3. The strongest and earliest induction due to ozone treatment could be observed for DAHP synthase. An isoform-specific analysis of the transcripts showed a strong induction on transcript level only for one of three isoforms, which was followed by the induction of the DAHP synthase also on protein level. The different induction kinetics of the prechorismate pathway genes indicate that their regulation in response to ozone might be regulated by different signals, for example, ethylene, reactive oxygen species or salicylic acid, which also occur with different kinetics and thus may play different roles in the plant response to ozone.
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Affiliation(s)
- I Janzik
- Research Centre Jülich GmbH, Institute Phytosphere (ICG III), 52425 Jülich, Germany.
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12
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Ekman DR, Wolfe NL, Dean JFD. Gene expression changes in Arabidopsis thaliana seedling roots exposed to the munition hexahydro-1,3,5-trinitro-1,3,5-triazine. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2005; 39:6313-20. [PMID: 16173598 DOI: 10.1021/es050385r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Arabidopsis thaliana root transcriptome responses to the munition, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), were assessed using serial analysis of gene expression (SAGE). Sequencing of SAGE libraries from control and RDX-exposed root tissues revealed induction of genes known to respond to a variety of general stresses. Among the highly induced genes were several encoding molecular chaperones and transcription factors as well as vacuolar proteins and peroxidases. Strongly repressed transcripts included ones encoding ribosomal proteins, a cyclophilin, a katanin, and a peroxidase. Comparison of the transcriptional profile for the RDX response to a profile previously described for Arabidopsis roots exposed to trinitrotoluene (TNT) revealed significant differences in the inferred gene expression patterns. This suggests that Arabidopsis employs drastically different mechanisms for coping with these two compounds. With respect to the goal of engineering plants to better tolerate and degrade explosives at contaminated sites, these results suggest that enhancement of different genes and metabolic pathways may be required to deal effectively with each type of explosive. This has ramifications for phytoremediation efforts since many contaminated sites harbor both compounds.
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Affiliation(s)
- Drew R Ekman
- National Exposure Research Laboratory, Ecosystems Research Division, U.S. Environmental Protection Agency, Athens, Georgia 30605, USA
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13
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Entus R, Poling M, Herrmann KM. Redox regulation of Arabidopsis 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase. PLANT PHYSIOLOGY 2002; 129:1866-71. [PMID: 12177500 PMCID: PMC166775 DOI: 10.1104/pp.002626] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The cDNA for 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase of Arabidopsis encodes a polypeptide with an amino-terminal signal sequence for plastid import. A cDNA fragment encoding the processed form of the enzyme was expressed in Escherichia coli. The resulting protein was purified to electrophoretic homogeneity. The enzyme requires Mn(2+) and reduced thioredoxin (TRX) for activity. Spinach (Spinacia oleracea) TRX f has an apparent dissociation constant for the enzyme of about 0.2 microM. The corresponding constant for TRX m is orders of magnitude higher. In the absence of TRX, dithiothreitol partially activates the enzyme. Upon alkylation of the enzyme with iodoacetamide, the dependence on a reducing agent is lost. These results indicate that the first enzyme in the shikimate pathway of Arabidopsis appears to be regulated by the ferredoxin/TRX redox control of the chloroplast.
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Affiliation(s)
- Robert Entus
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907, USA
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14
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Bischoff M, Schaller A, Bieri F, Kessler F, Amrhein N, Schmid J. Molecular characterization of tomato 3-dehydroquinate dehydratase-shikimate:NADP oxidoreductase. PLANT PHYSIOLOGY 2001; 125:1891-900. [PMID: 11299368 PMCID: PMC88844 DOI: 10.1104/pp.125.4.1891] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2000] [Accepted: 12/11/2000] [Indexed: 05/20/2023]
Abstract
Analysis of cDNAs encoding the bifunctional 3-dehydroquinate dehydratase-shikimate:NADP oxidoreductase (DHQase-SORase) from tomato (Lycopersicon esculentum) revealed two classes of cDNAs that differed by 57 bp within the coding regions, but were otherwise identical. Comparison of these cDNA sequences with the sequence of the corresponding single gene unequivocally proved that the primary transcript is differentially spliced, potentially giving rise to two polypeptides that differ by 19 amino acids. Quantitative real-time polymerase chain reaction revealed that the longer transcript constitutes at most 1% to 2% of DHQase-SORase transcripts. Expression of the respective polypeptides in Escherichia coli mutants lacking the DHQase or the SORase activity gave functional complementation only in case of the shorter polypeptide, indicating that skipping of a potential exon is a prerequisite for the production of an enzymatically active protein. The deduced amino acid sequence revealed that the DHQase-SORase is most likely synthesized as a precursor with a very short (13-amino acid) plastid-specific transit peptide. Like other genes encoding enzymes of the prechorismate pathway in tomato, this gene is elicitor-inducible. Tissue-specific expression resembles the patterns obtained for 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase 2 and dehydroquinate synthase genes. This work completes our studies of the prechorismate pathway in that cDNAs for all seven enzymes (including isozymes) of the prechorismate pathway from tomato have now been characterized.
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Affiliation(s)
- M Bischoff
- Institute of Plant Sciences, Swiss Federal Institute of Technology, Universitätstrasse 2, CH-8092 Zurich, Switzerland
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15
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He X, Agnihotri G, Liu Hw HW. Novel enzymatic mechanisms in carbohydrate metabolism. Chem Rev 2000; 100:4615-62. [PMID: 11749360 DOI: 10.1021/cr9902998] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- X He
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712
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16
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Janzik I, Macheroux P, Amrhein N, Schaller A. LeSBT1, a subtilase from tomato plants. Overexpression in insect cells, purification, and characterization. J Biol Chem 2000; 275:5193-9. [PMID: 10671566 DOI: 10.1074/jbc.275.7.5193] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cDNA of a tomato subtilase designated LeSBT1 was cloned from a tomato flower cDNA library. The deduced amino acid sequence indicated for LeSBT1 the structure of a prepro-protein targeted to the secretory pathway by virtue of an amino-terminal signal peptide. LeSBT1 was expressed in the baculovirus/insect cell system and a processed 73-kDa form of LeSBT1, lacking both signal peptide and prodomain, was purified to homogeneity from culture supernatants. This 73-kDa LeSBT1, however, lacked proteolytic activity. Zymogen activation to yield 68-kDa LeSBT1 required the additional processing of an amino-terminal autoinhibitory peptide in a strictly pH-dependent manner. Mature 68-kDa LeSBT1 showed highest activity at acidic pH consistent with its presumed localization in the apoplast of the plant cell. In comparison to other plant subtilases, LeSBT1 exhibited a narrower substrate specificity in that it cleaves only polypeptide substrates preferentially but not exclusively carboxyl-terminal of glutamine residues. The possible involvement of LeSBT1 in selective proprotein processing is discussed with reference to the related mammalian proprotein convertases.
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Affiliation(s)
- I Janzik
- Institute of Plant Sciences, Federal Institute of Technology Zürich, Universitätstrasse 2, CH-8092 Zürich, Switzerland
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17
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Mobley EM, Kunkel BN, Keith B. Identification, characterization and comparative analysis of a novel chorismate mutase gene in Arabidopsis thaliana. Gene 1999; 240:115-23. [PMID: 10564818 DOI: 10.1016/s0378-1119(99)00423-0] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phenylalanine, tyrosine, and tryptophan have a dual biosynthetic role in plants; they are required for protein synthesis and are also precursors to a number of aromatic secondary metabolites critical to normal development and stress responses. Whereas much has been learned in recent years about the genetic control of tryptophan biosynthesis in Arabidopsis and other plants, relatively little is known about the genetic regulation of phenylalanine and tyrosine synthesis. We have isolated, characterized and determined the expression of Arabidopsis thaliana genes encoding chorismate mutase, the enzyme catalyzing the first committed step in phenylalanine and tyrosine synthesis. Three independent Arabidopsis chorismate mutase cDNAs were isolated by functional complementation of a Saccharomyces cerevisiae mutation. Two of these cDNAs have been reported independently (Eberhard et al., 1993. FEBS 334, 233-236; Eberhard et al., 1996. Plant J. 10, 815-821), but the third (designated CM-3) represents a novel gene. The different organ-specific expression patterns of these cDNAs, their regulation in response to pathogen infiltration, as well as the different enzymatic characteristics of the proteins they encode are also described. Together, these data suggest that each isoform may play a distinct physiological role in coordinating chorismate mutase activity with developmental and environmental signals.
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MESH Headings
- Amino Acid Sequence
- Amino Acids, Cyclic/pharmacology
- Arabidopsis/enzymology
- Arabidopsis/genetics
- Blotting, Northern
- Chorismate Mutase/drug effects
- Chorismate Mutase/genetics
- Chorismate Mutase/metabolism
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- Gene Expression Regulation, Enzymologic
- Gene Expression Regulation, Plant
- Genes, Plant/genetics
- Genetic Complementation Test
- Isoenzymes/drug effects
- Isoenzymes/genetics
- Isoenzymes/metabolism
- Kinetics
- Molecular Sequence Data
- Mutation
- RNA, Plant/genetics
- RNA, Plant/metabolism
- Saccharomyces cerevisiae/genetics
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Tissue Distribution
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Affiliation(s)
- E M Mobley
- Department of Biochemistry, University of Chicago, Chicago, IL, USA
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Abstract
The shikimate pathway links metabolism of carbohydrates to biosynthesis of aromatic compounds. In a sequence of seven metabolic steps, phosphoenolpyruvate and erythrose 4-phosphate are converted to chorismate, the precursor of the aromatic amino acids and many aromatic secondary metabolites. All pathway intermediates can also be considered branch point compounds that may serve as substrates for other metabolic pathways. The shikimate pathway is found only in microorganisms and plants, never in animals. All enzymes of this pathway have been obtained in pure form from prokaryotic and eukaryotic sources and their respective DNAs have been characterized from several organisms. The cDNAs of higher plants encode proteins with amino terminal signal sequences for plastid import, suggesting that plastids are the exclusive locale for chorismate biosynthesis. In microorganisms, the shikimate pathway is regulated by feedback inhibition and by repression of the first enzyme. In higher plants, no physiological feedback inhibitor has been identified, suggesting that pathway regulation may occur exclusively at the genetic level. This difference between microorganisms and plants is reflected in the unusually large variation in the primary structures of the respective first enzymes. Several of the pathway enzymes occur in isoenzymic forms whose expression varies with changing environmental conditions and, within the plant, from organ to organ. The penultimate enzyme of the pathway is the sole target for the herbicide glyphosate. Glyphosate-tolerant transgenic plants are at the core of novel weed control systems for several crop plants.
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Affiliation(s)
- Klaus M. Herrmann
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907; e-mail: , Monsanto Company, St. Louis, Missouri 63198; e-mail:
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19
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Affiliation(s)
- P M Dewick
- School of Pharmaceutical Sciences, University of Nottingham, UK
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Eberhard J, Bischoff M, Raesecke HR, Amrhein N, Schmid J. Isolation of a cDNA from tomato coding for an unregulated, cytosolic chorismate mutase. PLANT MOLECULAR BIOLOGY 1996; 31:917-922. [PMID: 8806422 DOI: 10.1007/bf00019479] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A cDNA coding for chorismate mutase was isolated from tomato by complementing a chorismate mutase-deficient Escherichia coli strain with a cDNA library. Southern blot analysis suggests the existence of a single gene of this chorismate mutase type per haploid tomato genome. The abundance of the corresponding transcripts was highest in roots, lower in stems and cotyledons, and even lower in flowers and leaves. The activity of the protein expressed in E. coli was not regulated by the three aromatic amino acids. Characteristics of the sequence and of the enzymatic activity suggest that the identified cDNA encodes a cytosolic, unregulated CM-2 type chorismate mutase.
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Affiliation(s)
- J Eberhard
- Institute of Plant Sciences, Swiss Federal Institute of Technology, Zürich, Switzerland
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