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Barker R, Fernandez Garcia MN, Powers SJ, Vaughan S, Bennett MJ, Phillips AL, Thomas SG, Hedden P. Mapping sites of gibberellin biosynthesis in the Arabidopsis root tip. THE NEW PHYTOLOGIST 2021; 229:1521-1534. [PMID: 32989730 DOI: 10.1111/nph.16967] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/05/2020] [Indexed: 05/20/2023]
Abstract
Root elongation depends on the action of the gibberellin (GA) growth hormones, which promote cell production in the root meristem and cell expansion in the elongation zone. Sites of GA biosynthesis in the roots of 7-d-old Arabidopsis thaliana seedlings were investigated using tissue-specific GA inactivation in wild-type (Col-0) or rescue of GA-deficient dwarf mutants. Tissue-specific GA depletion was achieved by ectopic expression of the GA-inactivating enzyme AtGA2ox2, which is specific for C19 -GAs, and AtGA2ox7, which acts on C20 -GA precursors. In addition, tissue-specific rescue of ga20ox triple and ga3ox double mutants was shown. Furthermore, GUS reporter lines for major GA20ox, GA3ox and GA2ox genes were used to observe their expression domains in the root. The effects of expressing these constructs on the lengths of the root apical meristem and cortical cells in the elongation zone confirmed that roots are autonomous for GA biosynthesis, which occurs in multiple tissues, with the endodermis a major site of synthesis. The results are consistent with the early stages of GA biosynthesis within the root occurring in the meristematic region and indicate that the penultimate step of GA biosynthesis, GA 20-oxidation, is required in both the meristem and elongation zone.
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Affiliation(s)
- Richard Barker
- Rothamsted Research, Harpenden, Hertfordshire,, AL5 2JQ, UK
- Plant & Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington,, LE12 5RD, UK
| | - Maria Nieves Fernandez Garcia
- Department of Abiotic Stress and Plant Pathology, Centro de Edafología y Biología Aplicada del Segura (CSIC), Murcia, Spain
| | | | - Simon Vaughan
- Rothamsted Research, Harpenden, Hertfordshire,, AL5 2JQ, UK
| | - Malcolm J Bennett
- Plant & Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington,, LE12 5RD, UK
| | | | | | - Peter Hedden
- Rothamsted Research, Harpenden, Hertfordshire,, AL5 2JQ, UK
- Laboratory of Growth Regulators,Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany, Czech Academy of Sciences, Olomouc, CZ-783 71, Czech Republic
- Faculty of Science, Palacký University, Olomouc, CZ-783 71, Czech Republic
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2
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Synthesis and Biological Evaluation of 3,3-Dimethyl-1-(1H-1,2,4-triazole-1-yl)butan-2-One Derivatives as Plant Growth Regulators. Chem Res Chin Univ 2019. [DOI: 10.1007/s40242-019-8303-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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3
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Physical and thermodynamic characterization of the rice gibberellin receptor/gibberellin/DELLA protein complex. Sci Rep 2018; 8:17719. [PMID: 30531945 PMCID: PMC6286387 DOI: 10.1038/s41598-018-35765-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 11/09/2018] [Indexed: 11/18/2022] Open
Abstract
Gibberellins (GAs) are phytohormones that regulate various developmental processes in plants. The initial GA signalling events involve the binding of a GA to the soluble GA receptor protein GID1, followed by the binding of the complex to the negative transcriptional regulator of GA signaling, the DELLA protein. Although X-ray structures for certain Arabidopsis GID1/GA/DELLA protein complexes have previously been determined, examination of these complexes did not fully clarify how a DELLA protein recognizes and binds to a GID1/GA complex. Herein, we present a study aimed at physically defining, via a combination of gel chromatography, isothermal titration calorimetry (ITC), small-angle X-ray scattering experiments (SAXS), NMR spectroscopy and mutagenesis, how the rice DELLA protein (SLR1) binds to the rice GID1/GA complex. We have identified the shortest SLR1 sequence (M28-A112) that binds the rice GID/GA complex tightly. The binding constant for the ternary complex that includes SLR1(M28-A112) is 2.9 × 107 M−1; the binding is enthalpically driven and does not depend on the chemical nature of the bound GA. Furthermore, the results of SAXS, ITC, and gel filtration experiments indicate that when free in solution, SLR1(M28-A112) is a natively unfolded protein. The NMR experiments expand this observation to show that the unfolded mutant also contains a small amount of marginally stable secondary structure. Conversely, the protein has a highly ordered structure when bound one-to-one to GID1/GA.
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Aihua L, Shunyuan J, Guang Y, Ying L, Na G, Tong C, Liping K, Luqi H. Molecular mechanism of seed dormancy release induced by fluridone compared with cod stratification in Notopterygium incisum. BMC PLANT BIOLOGY 2018; 18:116. [PMID: 29890940 PMCID: PMC5996521 DOI: 10.1186/s12870-018-1333-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 05/24/2018] [Indexed: 05/30/2023]
Abstract
BACKGROUND Notopterygium incisum is an important Chinese medicinal plant. Its mature seeds have underdeveloped embryos and are physiological dormant. We found the seeds with full developed embryos can germinate after treated by fluridone (FL), an inhibitor of abscisic acid (ABA). In order to understand the molecular mechanisms underlying seed dormancy release by FL, we compared the transcriptomic changes in dormancy release induced by two different methods, FL and cold stratification (CS) in N. incisum. We further analyzed the gene expression patterns involved in seed germination and dormancy using quantitative reverse-transcription PCR. RESULTS RNA-sequence analysis revealed more dramatic changes in the transcriptomes of FL than those in CS, particularly for genes involved in the biosynthesis and regulation of gibberellins (GAs) and ABA. The down-regulation of ABA biosynthesis genes and the dramatic up-regulation of NiCYP707As, an ABA catabolic gene, contributed to the reduced ABA levels in FL. The increased GA3 levels in CS-treated seeds were due to the up-regulation of NiGA3OX. Both NiABI5 (a positive ABA regulator) and NiGAI (a negative regulator of GA) were down-regulated in FL and CS. The upregulation of strigolactones (SLs; the metabolites with the same precursor as ABA) biosynthesis and regulatory genes in both FL- and CS-treated seeds indicates that SLs contribute positively to seed dormancy release in N. incisum. CONCLUSIONS Our results indicated that FL- and CS-seed dormancy release possibly depends on two totally different mechanisms: alleviation of the effects of ABA and potentiation of the effects of GA, respectively. However, NiABI5 and NiGAI probably function as common factors integrating the effects of ABA and GA on seed dormancy release.
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Affiliation(s)
- Li Aihua
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700 People’s Republic of China
- Flow Station of Post-doctoral Scientific Research, China Academy of Chinese Medical Sciences, Beijing, 100700 People’s Republic of China
| | - Jiang Shunyuan
- Sichuan Key Laboratory of Quality and Innovation Research of Chinese Materia Medica, Sichuan Academy of Chinese Medicine Sciences, Chengdu, 610041 People’s Republic of China
| | - Yang Guang
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700 People’s Republic of China
| | - Li Ying
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700 People’s Republic of China
| | - Guo Na
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, 100700 People’s Republic of China
| | - Chen Tong
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700 People’s Republic of China
| | - Kang Liping
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700 People’s Republic of China
| | - Huang Luqi
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700 People’s Republic of China
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Nett RS, Dickschat JS, Peters RJ. Labeling Studies Clarify the Committed Step in Bacterial Gibberellin Biosynthesis. Org Lett 2016; 18:5974-5977. [PMID: 27934361 PMCID: PMC5139915 DOI: 10.1021/acs.orglett.6b02569] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Bacteria
have evolved gibberellin phytohormone biosynthesis independently
of plants and fungi. Through 13C-labeling and NMR analysis,
the mechanistically unusual “B” ring contraction catalyzed
by a cytochrome P450 (CYP114), which is the committed step in gibberellin
biosynthesis, was shown to occur via oxidative extrusion of carbon-7
from ent-kaurenoic acid in bacteria. This is identical
to the convergently evolved chemical transformation in plants and
fungi, suggesting a common semipinacol rearrangement mechanism potentially
guided by carbon-4α carboxylate proximity.
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Affiliation(s)
- Ryan S Nett
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University , Ames, Iowa 50011, United States
| | - Jeroen S Dickschat
- Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn , Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Reuben J Peters
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University , Ames, Iowa 50011, United States
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Pearce S, Huttly AK, Prosser IM, Li YD, Vaughan SP, Gallova B, Patil A, Coghill JA, Dubcovsky J, Hedden P, Phillips AL. Heterologous expression and transcript analysis of gibberellin biosynthetic genes of grasses reveals novel functionality in the GA3ox family. BMC PLANT BIOLOGY 2015; 15:130. [PMID: 26044828 PMCID: PMC4455330 DOI: 10.1186/s12870-015-0520-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 05/01/2015] [Indexed: 05/18/2023]
Abstract
BACKGROUND The gibberellin (GA) pathway plays a central role in the regulation of plant development, with the 2-oxoglutarate-dependent dioxygenases (2-ODDs: GA20ox, GA3ox, GA2ox) that catalyse the later steps in the biosynthetic pathway of particularly importance in regulating bioactive GA levels. Although GA has important impacts on crop yield and quality, our understanding of the regulation of GA biosynthesis during wheat and barley development remains limited. In this study we identified or assembled genes encoding the GA 2-ODDs of wheat, barley and Brachypodium distachyon and characterised the wheat genes by heterologous expression and transcript analysis. RESULTS The wheat, barley and Brachypodium genomes each contain orthologous copies of the GA20ox, GA3ox and GA2ox genes identified in rice, with the exception of OsGA3ox1 and OsGA2ox5 which are absent in these species. Some additional paralogs of 2-ODD genes were identified: notably, a novel gene in the wheat B genome related to GA3ox2 was shown to encode a GA 1-oxidase, named as TaGA1ox-B1. This enzyme is likely to be responsible for the abundant 1β-hydroxylated GAs present in developing wheat grains. We also identified a related gene in barley, located in a syntenic position to TaGA1ox-B1, that encodes a GA 3,18-dihydroxylase which similarly accounts for the accumulation of unusual GAs in barley grains. Transcript analysis showed that some paralogs of the different classes of 2-ODD were expressed mainly in a single tissue or at specific developmental stages. In particular, TaGA20ox3, TaGA1ox1, TaGA3ox3 and TaGA2ox7 were predominantly expressed in developing grain. More detailed analysis of grain-specific gene expression showed that while the transcripts of biosynthetic genes were most abundant in the endosperm, genes encoding inactivation and signalling components were more highly expressed in the seed coat and pericarp. CONCLUSIONS The comprehensive expression and functional characterisation of the multigene families encoding the 2-ODD enzymes of the GA pathway in wheat and barley will provide the basis for a better understanding of GA-regulated development in these species. This analysis revealed the existence of a novel, endosperm-specific GA 1-oxidase in wheat and a related GA 3,18-dihydroxylase enzyme in barley that may play important roles during grain expansion and development.
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Affiliation(s)
- Stephen Pearce
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA.
| | - Alison K Huttly
- Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, AL5 2JQ, UK.
| | - Ian M Prosser
- Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, AL5 2JQ, UK.
| | - Yi-dan Li
- Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, AL5 2JQ, UK.
- Biotechnology Research Centre, Jilin Academy of Agricultural Sciences, Changchun, 130033, China.
| | - Simon P Vaughan
- Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, AL5 2JQ, UK.
| | - Barbora Gallova
- Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, AL5 2JQ, UK.
| | - Archana Patil
- Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, AL5 2JQ, UK.
| | - Jane A Coghill
- University of Bristol Transcriptomics Facility, School of Biological Sciences, Bristol, BS8 1UG, UK.
| | - Jorge Dubcovsky
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA.
- Howard Hughes Medical Institute, Chevy Chase, MD, 20815, USA.
| | - Peter Hedden
- Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, AL5 2JQ, UK.
| | - Andrew L Phillips
- Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, AL5 2JQ, UK.
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Maheshwari DK, Dheeman S, Agarwal M. Phytohormone-Producing PGPR for Sustainable Agriculture. BACTERIAL METABOLITES IN SUSTAINABLE AGROECOSYSTEM 2015. [DOI: 10.1007/978-3-319-24654-3_7] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Pimenta Lange MJ, Liebrandt A, Arnold L, Chmielewska SM, Felsberger A, Freier E, Heuer M, Zur D, Lange T. Functional characterization of gibberellin oxidases from cucumber, Cucumis sativus L. PHYTOCHEMISTRY 2013; 90:62-9. [PMID: 23507362 DOI: 10.1016/j.phytochem.2013.02.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Revised: 02/04/2013] [Accepted: 02/14/2013] [Indexed: 05/06/2023]
Abstract
Cucurbits have been used widely to elucidate gibberellin (GA) biosynthesis. With the recent availability of the genome sequence for the economically important cucurbit Cucumis sativus, sequence data became available for all genes potentially involved in GA biosynthesis for this species. Sixteen cDNAs were cloned from root and shoot of 3-d to 7-d old seedlings and from mature seeds of C. sativus. Two cDNAs code for GA 7-oxidases (CsGA7ox1, and -2), five for GA 20-oxidases (CsGA20ox1, -2, -3, -4, and -5), four for GA 3-oxidases (CsGA3ox1, -2, -3, and -4), and another five for GA 2-oxidases (CsGA2ox1, -2, -3, -4, and -5). Their enzymatic activities were investigated by heterologous expression of the cDNAs in Escherichia coli and incubation of the cell lysates with (14)C-labelled, D2-labelled, or unlabelled GA-substrates. The two GA 7-oxidases converted GA12-aldehyde to GA12 efficiently. CsGA7ox1 converted GA12 to GA14, to 15α-hydroxyGA12, and further to 15α-hydroxyGA14. CsGA7ox2 converted GA12 to its 12α-hydroxylated analogue GA111. All five GA 20-oxidases converted GA12 to GA9 as a major product, and to GA25 as a minor product. The four GA 3-oxidases oxidized the C19-GA GA9 to GA4 as the only product. In addition, three of them (CsGA3ox2, -3, and -4) converted the C20-GA GA12 to GA14. The GA 2-oxidases CsGA2ox1, -2, -3, and -4 oxidized the C19-GAs GA9 and GA4 to GA34 and GA51, respectively. CsGA2ox2, -3, and -4 converted GA51 and GA34 further to respective GA-catabolites. In addition to C19-GAs, CsGA2ox4 also converted the C20-GA GA12 to GA110. In contrast, CsGA2ox5 oxidized only the C20 GA12 to GA110 as the sole product. As shown for CsGA20ox1 and CsGA3ox1, similar reactions were catalysed with 13-hydroxlyated GAs as substrates. It is likely that these enzymes are also responsible for the biosynthesis of 13-hydroxylated GAs in vivo that occur at low levels in cucumber.
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Affiliation(s)
- Maria João Pimenta Lange
- Institut für Pflanzenbiologie, Technische Universität Braunschweig, Mendelssohnstr. 4, D-38106 Braunschweig, Germany
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Bhattacharya A, Kourmpetli S, Ward DA, Thomas SG, Gong F, Powers SJ, Carrera E, Taylor B, de Caceres Gonzalez FN, Tudzynski B, Phillips AL, Davey MR, Hedden P. Characterization of the fungal gibberellin desaturase as a 2-oxoglutarate-dependent dioxygenase and its utilization for enhancing plant growth. PLANT PHYSIOLOGY 2012; 160:837-45. [PMID: 22911627 PMCID: PMC3461559 DOI: 10.1104/pp.112.201756] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 08/20/2012] [Indexed: 05/19/2023]
Abstract
The biosynthesis of gibberellic acid (GA(3)) by the fungus Fusarium fujikuroi is catalyzed by seven enzymes encoded in a gene cluster. While four of these enzymes are characterized as cytochrome P450 monooxygenases, the nature of a fifth oxidase, GA(4) desaturase (DES), is unknown. DES converts GA(4) to GA(7) by the formation of a carbon-1,2 double bond in the penultimate step of the pathway. Here, we show by expression of the des complementary DNA in Escherichia coli that DES has the characteristics of a 2-oxoglutarate-dependent dioxygenase. Although it has low amino acid sequence homology with known 2-oxoglutarate-dependent dioxygenases, putative iron- and 2-oxoglutarate-binding residues, typical of such enzymes, are apparent in its primary sequence. A survey of sequence databases revealed that homologs of DES are widespread in the ascomycetes, although in most cases the homologs must participate in non-gibberellin (GA) pathways. Expression of des from the cauliflower mosaic virus 35S promoter in the plant species Solanum nigrum, Solanum dulcamara, and Nicotiana sylvestris resulted in substantial growth stimulation, with a 3-fold increase in height in S. dulcamara compared with controls. In S. nigrum, the height increase was accompanied by a 20-fold higher concentration of GA(3) in the growing shoots than in controls, although GA(1) content was reduced. Expression of des was also shown to partially restore growth in plants dwarfed by ectopic expression of a GA 2-oxidase (GA-deactivating) gene, consistent with GA(3) being protected from 2-oxidation. Thus, des has the potential to enable substantial growth increases, with practical implications, for example, in biomass production.
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MESH Headings
- Agrobacterium tumefaciens/genetics
- Agrobacterium tumefaciens/metabolism
- Caulimovirus/enzymology
- Caulimovirus/genetics
- Caulimovirus/metabolism
- Chromatography, High Pressure Liquid
- Cloning, Molecular
- DNA, Complementary/genetics
- DNA, Complementary/metabolism
- Databases, Genetic
- Enzyme Assays/methods
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Fungal Proteins/genetics
- Fungal Proteins/isolation & purification
- Fungal Proteins/metabolism
- Fusarium/enzymology
- Fusarium/genetics
- Genetic Vectors
- Gibberellins/biosynthesis
- Gibberellins/genetics
- Gibberellins/metabolism
- Ketoglutaric Acids/metabolism
- Mixed Function Oxygenases/genetics
- Mixed Function Oxygenases/isolation & purification
- Mixed Function Oxygenases/metabolism
- Molecular Sequence Data
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/growth & development
- Plants, Genetically Modified/metabolism
- Promoter Regions, Genetic
- Sequence Alignment
- Sequence Homology, Amino Acid
- Solanum/genetics
- Solanum/growth & development
- Solanum/metabolism
- Substrate Specificity
- Nicotiana/genetics
- Nicotiana/growth & development
- Nicotiana/metabolism
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Affiliation(s)
| | | | - Dennis A. Ward
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom (A.B., S.K., B.T., F.N.d.C.G., M.R.D.); Rothamsted Research, Harpenden AL5 2JQ, United Kingdom (D.A.W., F.G., S.G.T., S.J.P., E.C., A.L.P., P.H.); and Institüt für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D–48153, Muenster, Germany (B.T.)
| | - Stephen G. Thomas
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom (A.B., S.K., B.T., F.N.d.C.G., M.R.D.); Rothamsted Research, Harpenden AL5 2JQ, United Kingdom (D.A.W., F.G., S.G.T., S.J.P., E.C., A.L.P., P.H.); and Institüt für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D–48153, Muenster, Germany (B.T.)
| | - Fan Gong
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom (A.B., S.K., B.T., F.N.d.C.G., M.R.D.); Rothamsted Research, Harpenden AL5 2JQ, United Kingdom (D.A.W., F.G., S.G.T., S.J.P., E.C., A.L.P., P.H.); and Institüt für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D–48153, Muenster, Germany (B.T.)
| | - Stephen J. Powers
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom (A.B., S.K., B.T., F.N.d.C.G., M.R.D.); Rothamsted Research, Harpenden AL5 2JQ, United Kingdom (D.A.W., F.G., S.G.T., S.J.P., E.C., A.L.P., P.H.); and Institüt für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D–48153, Muenster, Germany (B.T.)
| | - Esther Carrera
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom (A.B., S.K., B.T., F.N.d.C.G., M.R.D.); Rothamsted Research, Harpenden AL5 2JQ, United Kingdom (D.A.W., F.G., S.G.T., S.J.P., E.C., A.L.P., P.H.); and Institüt für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D–48153, Muenster, Germany (B.T.)
| | - Benjamin Taylor
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom (A.B., S.K., B.T., F.N.d.C.G., M.R.D.); Rothamsted Research, Harpenden AL5 2JQ, United Kingdom (D.A.W., F.G., S.G.T., S.J.P., E.C., A.L.P., P.H.); and Institüt für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D–48153, Muenster, Germany (B.T.)
| | - Francisco Nuñez de Caceres Gonzalez
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom (A.B., S.K., B.T., F.N.d.C.G., M.R.D.); Rothamsted Research, Harpenden AL5 2JQ, United Kingdom (D.A.W., F.G., S.G.T., S.J.P., E.C., A.L.P., P.H.); and Institüt für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D–48153, Muenster, Germany (B.T.)
| | - Bettina Tudzynski
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom (A.B., S.K., B.T., F.N.d.C.G., M.R.D.); Rothamsted Research, Harpenden AL5 2JQ, United Kingdom (D.A.W., F.G., S.G.T., S.J.P., E.C., A.L.P., P.H.); and Institüt für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D–48153, Muenster, Germany (B.T.)
| | - Andrew L. Phillips
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom (A.B., S.K., B.T., F.N.d.C.G., M.R.D.); Rothamsted Research, Harpenden AL5 2JQ, United Kingdom (D.A.W., F.G., S.G.T., S.J.P., E.C., A.L.P., P.H.); and Institüt für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D–48153, Muenster, Germany (B.T.)
| | - Michael R. Davey
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom (A.B., S.K., B.T., F.N.d.C.G., M.R.D.); Rothamsted Research, Harpenden AL5 2JQ, United Kingdom (D.A.W., F.G., S.G.T., S.J.P., E.C., A.L.P., P.H.); and Institüt für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D–48153, Muenster, Germany (B.T.)
| | - Peter Hedden
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom (A.B., S.K., B.T., F.N.d.C.G., M.R.D.); Rothamsted Research, Harpenden AL5 2JQ, United Kingdom (D.A.W., F.G., S.G.T., S.J.P., E.C., A.L.P., P.H.); and Institüt für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D–48153, Muenster, Germany (B.T.)
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Kundu S. Distribution and prediction of catalytic domains in 2-oxoglutarate dependent dioxygenases. BMC Res Notes 2012; 5:410. [PMID: 22862831 PMCID: PMC3475032 DOI: 10.1186/1756-0500-5-410] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 06/29/2012] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The 2-oxoglutarate dependent superfamily is a diverse group of non-haem dioxygenases, and is present in prokaryotes, eukaryotes, and archaea. The enzymes differ in substrate preference and reaction chemistry, a factor that precludes their classification by homology studies and electronic annotation schemes alone. In this work, I propose and explore the rationale of using substrates to classify structurally similar alpha-ketoglutarate dependent enzymes. FINDINGS Differential catalysis in phylogenetic clades of 2-OG dependent enzymes, is determined by the interactions of a subset of active-site amino acids. Identifying these with existing computational methods is challenging and not feasible for all proteins. A clustering protocol based on validated mechanisms of catalysis of known molecules, in tandem with group specific hidden markov model profiles is able to differentiate and sequester these enzymes. Access to this repository is by a web server that compares user defined unknown sequences to these pre-defined profiles and outputs a list of predicted catalytic domains. The server is free and is accessible at the following URL (http://comp-biol.theacms.in/H2OGpred.html). CONCLUSIONS The proposed stratification is a novel attempt at classifying and predicting 2-oxoglutarate dependent function. In addition, the server will provide researchers with a tool to compare their data to a comprehensive list of HMM profiles of catalytic domains. This work, will aid efforts by investigators to screen and characterize putative 2-OG dependent sequences. The profile database will be updated at regular intervals.
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Affiliation(s)
- Siddhartha Kundu
- Department of Biochemistry, Army College of Medical Sciences, Delhi Cantt., New Delhi 110010, India.
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11
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Plackett AR, Powers SJ, Fernandez-Garcia N, Urbanova T, Takebayashi Y, Seo M, Jikumaru Y, Benlloch R, Nilsson O, Ruiz-Rivero O, Phillips AL, Wilson ZA, Thomas SG, Hedden P. Analysis of the developmental roles of the Arabidopsis gibberellin 20-oxidases demonstrates that GA20ox1, -2, and -3 are the dominant paralogs. THE PLANT CELL 2012; 24:941-60. [PMID: 22427334 PMCID: PMC3336139 DOI: 10.1105/tpc.111.095109] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 02/16/2012] [Accepted: 02/27/2012] [Indexed: 05/18/2023]
Abstract
Gibberellin (GA) biosynthesis is necessary for normal plant development, with later GA biosynthetic stages being governed by multigene families. Arabidopsis thaliana contains five GA 20-oxidase (GA20ox) genes, and past work has demonstrated the importance of GA20ox1 and -2 for growth and fertility. Here, we show through systematic mutant analysis that GA20ox1, -2, and -3 are the dominant paralogs; their absence results in severe dwarfism and almost complete loss of fertility. In vitro analysis revealed that GA20ox4 has full GA20ox activity, but GA20ox5 catalyzes only the first two reactions of the sequence by which GA(12) is converted to GA(9). GA20ox3 functions almost entirely redundantly with GA20ox1 and -2 at most developmental stages, including the floral transition, while GA20ox4 and -5 have very minor roles. These results are supported by analysis of the gene expression patterns in promoter:β-glucuronidase reporter lines. We demonstrate that fertility is highly sensitive to GA concentration, that GA20ox1, -2, and -3 have significant effects on floral organ growth and anther development, and that both GA deficiency and overdose impact on fertility. Loss of GA20ox activity causes anther developmental arrest, with the tapetum failing to degrade. Some phenotypic recovery of late flowers in GA-deficient mutants, including ga1-3, indicated the involvement of non-GA pathways in floral development.
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Affiliation(s)
- Andrew R.G. Plackett
- Plant Science Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
| | - Stephen J. Powers
- Biomathematics and Bioinformatics Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
| | - Nieves Fernandez-Garcia
- Plant Science Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
| | - Terezie Urbanova
- Plant Science Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
| | | | - Mitsunori Seo
- RIKEN Plant Science Center, Yokohama, Kanagawa 230-0045, Japan
| | - Yusuke Jikumaru
- RIKEN Plant Science Center, Yokohama, Kanagawa 230-0045, Japan
| | - Reyes Benlloch
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-90183 Umea, Sweden
| | - Ove Nilsson
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-90183 Umea, Sweden
| | - Omar Ruiz-Rivero
- Plant Science Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
| | - Andrew L. Phillips
- Plant Science Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
| | - Zoe A. Wilson
- School of Biosciences, University of Nottingham, Loughborough, Leicestershire LE12 5RD, United Kingdom
| | - Stephen G. Thomas
- Plant Science Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
| | - Peter Hedden
- Plant Science Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
- Address correspondence to
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12
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Xiang H, Takeuchi H, Tsunoda Y, Nakajima M, Murata K, Ueguchi-Tanaka M, Kidokoro SI, Kezuka Y, Nonaka T, Matsuoka M, Katoh E. Thermodynamic characterization of OsGID1-gibberellin binding using calorimetry and docking simulations. J Mol Recognit 2011; 24:275-82. [PMID: 21360613 DOI: 10.1002/jmr.1049] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Gibberellins (GAs) are phytohormones regulating various developmental processes in plants. In rice, the initial GA-signaling events involve the binding of a GA to the soluble GA receptor protein, GID1. Although X-ray structures for certain GID1/GA complexes have recently been determined, an examination of the complexes does not fully clarify how GID1s discriminate among different GAs. Herein, we present a study aimed at defining the types of forces important to binding via a combination of isothermal titration calorimetry (ITC) and computational docking studies that employed rice GID1 (OsGID1), OsGID1 mutants, which were designed to have a decreased possible number of hydrogen bonds with bound GA, and GA variants. We find that, in general, GA binding is enthalpically driven and that a hydrogen bond between the phenolic hydroxyl of OsGID1 Tyr134 and the C-3 hydroxyl of a GA is a defining structural element. A hydrogen-bond network that involves the C-6 carboxyl of a GA that directly hydrogen bonds the hydroxyl of Ser198 and indirectly, via a two-water-molecule network, the phenolic hydroxyl of Tyr329 and the NH of the amide side-chain of Asn255 is also important for GA binding. The binding of OsGID1 by GA(1) is the most enthalpically driven association found for the biologically active GAs evaluated in this study. This observation might be a consequence of a hydrogen bond formed between the hydroxyl at the C-13 position of GA(1) and the main chain carbonyl of OsGID1 Phe245. Our results demonstrate that by combining ITC experiments and computational methods much can be learned about the thermodynamics of ligand/protein binding.
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Affiliation(s)
- Hongyu Xiang
- Division of Plant Research, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan
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13
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Ward DA, MacMillan J, Gong F, Phillips AL, Hedden P. Gibberellin 3-oxidases in developing embryos of the southern wild cucumber, Marah macrocarpus. PHYTOCHEMISTRY 2010; 71:2010-8. [PMID: 20965527 DOI: 10.1016/j.phytochem.2010.09.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 09/22/2010] [Accepted: 09/23/2010] [Indexed: 05/06/2023]
Abstract
Immature seeds of the southern wild cucumber, Marah macrocarpus, are a rich source of gibberellins (GAs) and were used in some of the earliest experiments on GA biosynthesis. The main biologically active GAs in developing embryos and endosperm of M. macrocarpus are GA(4) and GA(7), which have been shown previously to be formed from GA(9) in separate pathways, GA(4) being formed directly by 3β-hydroxylation, while GA(7) is produced in two steps via 2,3-didehydroGA(9). In order to identify the enzymes responsible for these conversions, three cDNA clones encoding functionally different GA 3-oxidases, MmGA3ox1, -2 and -3, were obtained from young immature M. macrocarpus embryos. Their biochemical functions were determined by expression of the cDNAs in Escherichia coli and incubation of cell lysates with (14)C-labelled substrates. MmGA3ox1 and MmGA3ox3 converted GA(9) to GA(4) as sole product, while MmGA3ox2 produced several products, including GA(4), 2,3-didehydroGA(9), 2,3-epoxyGA(9), GA(20) and GA(5), these last two products requiring 13-hydroxylation of GA(9) and 2,3-didehydroGA(9), respectively. MmGA3ox1 converted 2,3-didehydroGA(9) to GA(7), while MmGA3ox3 converted this substrate to the 2,3-epoxide, and MmGA3ox2 also formed the epoxide, but also GA(5.) Thus, formation of GA(7) requires the sequential activities of MmGA3ox2 and MmGA3ox1, while MmGA3ox3 is not involved in GA(7) production. The enzymes catalysed similar reactions when incubated with 13-hydroxylated GAs, although with reduced efficiencies. The 13-hydroxylase activity of MmGA3ox2 may be responsible for the production of GA(1) and GA(3), which are present at low levels in developing M. macrocarpus seeds.
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Affiliation(s)
- Dennis A Ward
- Rothamsted Research, Harpenden, Herts AL5 2JQ, United Kingdom
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14
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Pugliesi C, Fambrini M, Salvini M. Molecular Cloning and Expression Profile Analysis of Three Sunflower (Helianthus annuus) Diterpene Synthase Genes. Biochem Genet 2010; 49:46-62. [DOI: 10.1007/s10528-010-9384-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Accepted: 06/29/2010] [Indexed: 11/30/2022]
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15
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Jana CK, Scopelliti R, Gademann K. A synthetic entry into the taiwaniaquinoids based on a biogenetic hypothesis: total synthesis of (-)-taiwaniaquinone H. Chemistry 2010; 16:7692-5. [PMID: 20533471 DOI: 10.1002/chem.201001085] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Chandan Kumar Jana
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, CH-4056 Basel, Switzerland
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16
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Rieu I, Eriksson S, Powers SJ, Gong F, Griffiths J, Woolley L, Benlloch R, Nilsson O, Thomas SG, Hedden P, Phillips AL. Genetic analysis reveals that C19-GA 2-oxidation is a major gibberellin inactivation pathway in Arabidopsis. THE PLANT CELL 2008; 20:2420-36. [PMID: 18805991 PMCID: PMC2570722 DOI: 10.1105/tpc.108.058818] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 08/22/2008] [Accepted: 09/05/2008] [Indexed: 05/18/2023]
Abstract
Bioactive hormone concentrations are regulated both at the level of hormone synthesis and through controlled inactivation. Based on the ubiquitous presence of 2beta-hydroxylated gibberellins (GAs), a major inactivating pathway for the plant hormone GA seems to be via GA 2-oxidation. In this study, we used various approaches to determine the role of C(19)-GA 2-oxidation in regulating GA concentration and GA-responsive plant growth and development. We show that Arabidopsis thaliana has five C(19)-GA 2-oxidases, transcripts for one or more of which are present in all organs and at all stages of development examined. Expression of four of the five genes is subject to feed-forward regulation. By knocking out all five Arabidopsis C(19)-GA 2-oxidases, we show that C(19)-GA 2-oxidation limits bioactive GA content and regulates plant development at various stages during the plant life cycle: C(19)-GA 2-oxidases prevent seed germination in the absence of light and cold stimuli, delay the vegetative and floral phase transitions, limit the number of flowers produced per inflorescence, and suppress elongation of the pistil prior to fertilization. Under GA-limited conditions, further roles are revealed, such as limiting elongation of the main stem and side shoots. We conclude that C(19)-GA 2-oxidation is a major GA inactivation pathway regulating development in Arabidopsis.
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Affiliation(s)
- Ivo Rieu
- Centre for Crop Genetic Improvement, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom
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17
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Benschop JJ, Bou J, Peeters AJM, Wagemaker N, Gühl K, Ward D, Hedden P, Moritz T, Voesenek LACJ. Long-term submergence-induced elongation in Rumex palustris requires abscisic acid-dependent biosynthesis of gibberellin1. PLANT PHYSIOLOGY 2006; 141:1644-52. [PMID: 16766669 PMCID: PMC1533959 DOI: 10.1104/pp.106.082636] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Rumex palustris (polygonceae) responds to complete submergence with enhanced elongation of its youngest petioles. This process requires the presence of gibberellin (GA) and is associated with an increase in the concentration of GA1 in elongating petioles. We have examined how GA biosynthesis was regulated in submerged plants. Therefore, cDNAs encoding GA-biosynthetic enzymes GA 20-oxidase and GA 3-oxidase, and the GA-deactivating enzyme GA 2-oxidase were cloned from R. palustris and the kinetics of transcription of the corresponding genes was determined during a 24 h submergence period. The submergence-induced elongation response could be separated into several phases: (1) during the first phase of 4 h, petiole elongation was insensitive to GA; (2) from 4 to 6 h onward growth was limited by GA; and (3) from 15 h onward underwater elongation was dependent, but not limited by GA. Submergence induced an increase of GA1 concentration, as well as enhanced transcript levels of RpGA3ox1. Exogenous abscisic acid repressed the transcript levels of RpGA20ox1 and RpGA3ox1 and thus inhibited the submergence-induced increase in GA1. Abscisic acid had no effect on the tissue responsiveness to GA.
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Affiliation(s)
- Joris J Benschop
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Utrecht, Sorbonnelaan 16, 3584 CA, The Netherlands
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18
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Appleford NEJ, Evans DJ, Lenton JR, Gaskin P, Croker SJ, Devos KM, Phillips AL, Hedden P. Function and transcript analysis of gibberellin-biosynthetic enzymes in wheat. PLANTA 2006; 223:568-82. [PMID: 16160850 DOI: 10.1007/s00425-005-0104-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Accepted: 07/29/2005] [Indexed: 05/04/2023]
Abstract
The enzymes gibberellin (GA) 20-oxidase and 3-oxidase are major sites of regulation in GA biosynthesis. We have characterised one member of each of the gene families encoding these enzymes that are highly expressed in elongating stems and in developing and germinating grains of wheat and are therefore likely to have prominent developmental roles in these tissues. We mapped the three homoeologues of the GA 20-oxidase gene TaGA20ox1 to chromosomes 5BL, 5DL and 4AL. TaGA20ox1 is expressed mainly in the nodes and ears of the elongating stem, and also in developing and germinating embryos. Expression in the nodes, ears and germinating embryos is predominantly from the A and D genomes. Each homoeologous cDNA encodes a functional enzyme that catalyses the multi-step conversions of GA12-GA9, and GA53-GA20. Time course and enzyme kinetic studies indicate that the initial oxidation steps from GA12 and GA53 to the free alcohol forms of GA15 and GA44, respectively, occur rapidly but that subsequent steps occur more slowly. The intermediate GA19 has an especially low affinity for the enzyme, consistent with its accumulation in wheat tissues. The three homoeologous cDNAs for the 3-oxidase gene TaGA3ox2 encode functional enzymes, one of which was shown to possess low levels of 2beta-hydroxylase, 2,3-desaturase, 2,3-epoxidase and even 13-hydroxylase activities in addition to 3beta-hydroxylase activity. In contrast to TaGA20ox1, TaGA3ox2 is expressed in internodes, as well as nodes and the ear of the elongating stem. It is also highly expressed in developing and germinated embryos.
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19
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Radi A, Lange T, Niki T, Koshioka M, Lange MJP. Ectopic expression of pumpkin gibberellin oxidases alters gibberellin biosynthesis and development of transgenic Arabidopsis plants. PLANT PHYSIOLOGY 2006; 140:528-36. [PMID: 16384902 PMCID: PMC1361321 DOI: 10.1104/pp.105.073668] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Immature pumpkin (Cucurbita maxima) seeds contain gibberellin (GA) oxidases with unique catalytic properties resulting in GAs of unknown function for plant growth and development. Overexpression of pumpkin GA 7-oxidase (CmGA7ox) in Arabidopsis (Arabidopsis thaliana) resulted in seedlings with elongated roots, taller plants that flower earlier with only a little increase in bioactive GA4 levels compared to control plants. In the same way, overexpression of the pumpkin GA 3-oxidase1 (CmGA3ox1) resulted in a GA overdose phenotype with increased levels of endogenous GA4. This indicates that, in Arabidopsis, 7-oxidation and 3-oxidation are rate-limiting steps in GA plant hormone biosynthesis that control plant development. With an opposite effect, overexpression of pumpkin seed-specific GA 20-oxidase1 (CmGA20ox1) in Arabidopsis resulted in dwarfed plants that flower late with reduced levels of GA4 and increased levels of physiological inactive GA17 and GA25 and unexpected GA34 levels. Severe dwarfed plants were obtained by overexpression of the pumpkin GA 2-oxidase1 (CmGA2ox1) in Arabidopsis. This dramatic change in phenotype was accompanied by a considerable decrease in the levels of bioactive GA4 and an increase in the corresponding inactivation product GA34 in comparison to control plants. In this study, we demonstrate the potential of four pumpkin GA oxidase-encoding genes to modulate the GA plant hormone pool and alter plant stature and development.
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Affiliation(s)
- Abeer Radi
- Institut für Pflanzenbiologie der Technischen Universität Braunschweig, D-38106 Braunschweig, Germany
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20
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Lievens S, Goormachtig S, Den Herder J, Capoen W, Mathis R, Hedden P, Holsters M. Gibberellins are involved in nodulation of Sesbania rostrata. PLANT PHYSIOLOGY 2005; 139:1366-79. [PMID: 16258018 PMCID: PMC1283772 DOI: 10.1104/pp.105.066944] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Upon submergence, Azorhizobium caulinodans infects the semiaquatic legume Sesbania rostrata via the intercellular crack entry process, resulting in lateral root-based nodules. A gene encoding a gibberellin (GA) 20-oxidase, SrGA20ox1, involved in GA biosynthesis, was transiently up-regulated during lateral root base nodulation. Two SrGA20ox1 expression patterns were identified, one related to intercellular infection and a second observed in nodule meristem descendants. The infection-related expression pattern depended on bacterially produced nodulation (Nod) factors. Pharmacological studies demonstrated that GAs were involved in infection pocket and infection thread formation, two Nod factor-dependent events that initiate lateral root base nodulation, and that they were also needed for nodule primordium development. Moreover, GAs inhibited the root hair curling process. These results show that GAs are Nod factor downstream signals for nodulation in hydroponic growth.
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Affiliation(s)
- Sam Lievens
- Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology, Ghent University, B-9052 Gent, Belgium
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21
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Swain SM, Singh DP, Helliwell CA, Poole AT. Plants with increased expression of ent-kaurene oxidase are resistant to chemical inhibitors of this gibberellin biosynthesis enzyme. PLANT & CELL PHYSIOLOGY 2005; 46:284-91. [PMID: 15695465 DOI: 10.1093/pcp/pci027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The gibberellin (GA) biosynthetic pathway includes the three-step oxidation of ent-kaurene to ent-kaurenoic acid, catalyzed by the enzyme ent-kaurene oxidase (KO). Arabidopsis plants overexpressing the KO cDNA under the control of the cauliflower mosaic virus 35S promoter, with or without a translational fusion to a modified green fluorescent protein (GFP), are very similar to wild-type (WT) plants under normal growth conditions. In contrast, when WT and 35S:KO (or 35S:KO-GFP) seeds, seedlings or pollen tubes are grown in the presence of chemical inhibitors of KO, such as paclobutrazol and uniconazole, plants with increased KO expression are partially resistant to the effects of these inhibitors. In combination with the observation that decreased KO levels increase the sensitivity to KO inhibitors, the 35S:KO phenotypes demonstrate that the modification of KO enzyme levels could be used to create transgenic crop plants with altered KO inhibitor response. These results also suggest that the KO gene could be used as a selectable marker for plant regeneration based on resistance to KO inhibitors. Finally, the observation that pollen tubes expressing 35S:KO or 35S:KO-GFP have decreased sensitivity to KO inhibitors provides further evidence for a physiological role for GAs in pollen tube elongation.
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Affiliation(s)
- Stephen M Swain
- CSIRO Plant Industry, 585 River Ave, Merbein, Victoria 3505, Australia.
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22
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Isolation of Gibberellin-producing Penicillium spp. from the Root of Lindera obtusiloba and Vaccinium koreanum. THE KOREAN JOURNAL OF MYCOLOGY 2004. [DOI: 10.4489/kjm.2004.32.1.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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23
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Frisse A, Pimenta MJ, Lange T. Expression studies of gibberellin oxidases in developing pumpkin seeds. PLANT PHYSIOLOGY 2003; 131:1220-7. [PMID: 12644672 PMCID: PMC166882 DOI: 10.1104/pp.015206] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2002] [Revised: 10/25/2002] [Accepted: 12/01/2002] [Indexed: 05/18/2023]
Abstract
Two cDNA clones, 3-ox and 2-ox, have been isolated from developing pumpkin (Cucurbita maxima) embryos that show significant amino acid homology to gibberellin (GA) 3-oxidases and 2-oxidases, respectively. Recombinant fusion protein of clone 3-ox converted GA(12)-aldehyde, GA(12), GA(15), GA(24), GA(25), and GA(9) to GA(14)-aldehyde, GA(14), GA(37), GA(36), GA(13), and GA(4), respectively. Recombinant 2-ox protein oxidized GA(9), GA(4), and GA(1) to GA(51), GA(34), and GA(8), respectively. Previously cloned GA 7-oxidase revealed additional 3beta-hydroxylation activity of GA(12). Transcripts of this gene were identified in endosperm and embryo of the developing seed by quantitative reverse transcriptase-polymerase chain reaction and localized in protoderm, root apical meristem, and quiescent center by in situ hybridization. mRNA of the previously cloned GA 20-oxidase from pumpkin seeds was localized in endosperm and in tissues of protoderm, ground meristem, and cotyledons of the embryo. However, transcripts of the recently cloned GA 20-oxidase from pumpkin seedlings were found all over the embryo, and in tissues of the inner seed coat at the micropylar end. Previously cloned GA 2beta,3beta-hydroxylase mRNA molecules were specifically identified in endosperm tissue. Finally, mRNA molecules of the 3-ox and 2-ox genes were found in the embryo only. 3-ox transcripts were localized in tissues of cotyledons, protoderm, and inner cell layers of the root apical meristem, and 2-ox transcripts were found in all tissues of the embryo except the root tips. These results indicate tissue-specific GA-biosynthetic pathways operating within the developing seed.
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Affiliation(s)
- Andrea Frisse
- Institut für Pflanzenbiologie der Technischen Universität Braunschweig, Mendelssohnstrasse 4, D-38106 Braunschweig, Germany
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Kim J, Kang HG, Jun SH, Lee J, Yim J, An G. CvADH1, a member of short-chain alcohol dehydrogenase family, is inducible by gibberellin and sucrose in developing watermelon seeds. PLANT & CELL PHYSIOLOGY 2003; 44:85-92. [PMID: 12552151 DOI: 10.1093/pcp/pcg013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
To understand the molecular mechanisms that control seed formation, we selected a seed-preferential gene (CvADH1) from the ESTs of developing watermelon seeds. RNA blot analysis and in situ localization showed that CvADH1 was preferentially expressed in the nucellar tissue. The CvADH1 protein shared about 50% homology with short-chain alcohol dehydrogenase including ABA2 in Arabidopsis thaliana, stem secoisolariciresinol dehydrogenase in Forsythia intermedia, and 3beta-hydroxysterol dehydrogenase in Digitalis lanata. We investigated gene-expression levels in seeds from both normally pollinated fruits and those made parthenocarpic via N-(2-chloro-4-pyridyl)-N'-phenylurea treatment, the latter of which lack zygotic tissues. Whereas the transcripts of CvADH1 rapidly started to accumulate from about the pre-heart stage in normal seeds, they were not detectable in the parthenocarpic seeds. Treating the parthenogenic fruit with GA(3) strongly induced gene expression, up to the level accumulated in pollinated seeds. These results suggest that the CvADH1 gene is induced in maternal tissues by signals made in the zygotic tissues, and that gibberellin might be one of those signals. We also observed that CvADH1 expression was induced by sucrose in the parthenocarpic seeds. Therefore, we propose that the CvADH1 gene is inducible by gibberellin, and that sucrose plays an important role in the maternal tissues of watermelon during early seed development.
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Affiliation(s)
- Joonyul Kim
- National Research Laboratory of Plant Functional Genomics, Division of Molecular and Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, 790-784 Korea
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Singh DP, Jermakow AM, Swain SM. Gibberellins are required for seed development and pollen tube growth in Arabidopsis. THE PLANT CELL 2002; 14:3133-47. [PMID: 12468732 PMCID: PMC151207 DOI: 10.1105/tpc.003046] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2002] [Accepted: 09/13/2002] [Indexed: 05/18/2023]
Abstract
Gibberellins (GAs) are tetracyclic diterpenoids that are essential endogenous regulators of plant growth and development. GA levels within the plant are regulated by a homeostatic mechanism that includes changes in the expression of a family of GA-inactivating enzymes known as GA 2-oxidases. Ectopic expression of a pea GA 2-oxidase2 cDNA caused seed abortion in Arabidopsis, extending and confirming previous observations obtained with GA-deficient mutants of pea, suggesting that GAs have an essential role in seed development. A new physiological role for GAs in pollen tube growth in vivo also has been identified. The growth of pollen tubes carrying the 35S:2ox2 transgene was reduced relative to that of nontransgenic pollen, and this phenotype could be reversed partially by GA application in vitro or by combining with spy-5, a mutation that increases GA response. Treatment of wild-type pollen tubes with an inhibitor of GA biosynthesis in vitro also suggested that GAs are required for normal pollen tube growth. These results extend the known physiological roles of GAs in Arabidopsis development and suggest that GAs are required for normal pollen tube growth, a physiological role for GAs that has not been established previously.
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Affiliation(s)
- Davinder P Singh
- Commonwealth Scientific and Industrial Research Organization-Plant Industry, Private Mail Bag, Merbein, Victoria 3505, Australia
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Kang HG, Jun SH, Kim J, Kawaide H, Kamiya Y, An G. Cloning of gibberellin 3 beta-hydroxylase cDNA and analysis of endogenous gibberellins in the developing seeds in watermelon. PLANT & CELL PHYSIOLOGY 2002; 43:152-8. [PMID: 11867694 DOI: 10.1093/pcp/pcf016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We have isolated Cv3h, a cDNA clone from the developing seeds of watermelon, and have demonstrated significant amino acid homology with gibberellin (GA) 3 beta-hydroxylases. This cDNA clone was expressed in Escherichia coli as a fusion protein that oxidized GA(9) and GA(12) to GA(4) and GA(14), respectively. The Cv3h protein had the highest similarity with pumpkin GA 2 beta,3 beta-hydroxylase, but did not possess 2 beta-hydroxylation function. RNA blot analysis showed that the gene was expressed primarily in the inner parts of developing seeds, up to 10 d after pollination (DAP). In the parthenocarpic fruits induced by treatment with 1-(2-chloro-4-pyridyl)-3-phenylurea (CPPU), the embryo and endosperm of the seeds were undeveloped, whereas the integumental tissues, of maternal origin, showed nearly normal development. Cv3h mRNA was undetectable in the seeds of CPPU-treated fruits, indicating that the GA 3 beta-hydroxylase gene was expressed in zygotic cells. In our analysis of endogenous GAs from developing seeds, GA(9) and GA(4) were detected at high levels but those of GA(20) and GA(1) were very low. This demonstrates that GA biosynthesis in seeds prefers a non-13-hydroxylation pathway over an early 13-hydroxylation pathway. We also analyzed endogenous GAs from seeds of the parthenocarpic fruits. The level of bioactive GA(4 )was much lower there than in normal seeds, indicating that bioactive GAs, unconnected with Cv3h, exist in integumental tissues during early seed development.
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Affiliation(s)
- Hong-Gyu Kang
- National Research Laboratory of Plant Functional Genomics, Division of Molecular Life Science, Pohang University of Science and Technology, Pohang, 790-784 Korea
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Tudzynski B, Hedden P, Carrera E, Gaskin P. The P450-4 gene of Gibberella fujikuroi encodes ent-kaurene oxidase in the gibberellin biosynthesis pathway. Appl Environ Microbiol 2001; 67:3514-22. [PMID: 11472927 PMCID: PMC93051 DOI: 10.1128/aem.67.8.3514-3522.2001] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
At least five genes of the gibberellin (GA) biosynthesis pathway are clustered on chromosome 4 of Gibberella fujikuroi; these genes encode the bifunctional ent-copalyl diphosphate synthase/ent-kaurene synthase, a GA-specific geranylgeranyl diphosphate synthase, and three cytochrome P450 monooxygenases. We now describe a fourth cytochrome P450 monooxygenase gene (P450-4). Gas chromatography-mass spectrometry analysis of extracts of mycelia and culture fluid of a P450-4 knockout mutant identified ent-kaurene as the only intermediate of the GA pathway. Incubations with radiolabeled precursors showed that the metabolism of ent-kaurene, ent-kaurenol, and ent-kaurenal was blocked in the transformants, whereas ent-kaurenoic acid was metabolized efficiently to GA(4). The GA-deficient mutant strain SG139, which lacks the 30-kb GA biosynthesis gene cluster, converted ent-kaurene to ent-kaurenoic acid after transformation with P450-4. The B1-41a mutant, described as blocked between ent-kaurenal and ent-kaurenoic acid, was fully complemented by P450-4. There is a single nucleotide difference between the sequence of the B1-41a and wild-type P450-4 alleles at the 3' consensus sequence of intron 2 in the mutant, resulting in reduced levels of active protein due to a splicing defect in the mutant. These data suggest that P450-4 encodes a multifunctional ent-kaurene oxidase catalyzing all three oxidation steps between ent-kaurene and ent-kaurenoic acid.
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Affiliation(s)
- B Tudzynski
- Westfälische Wilhelms-Universität Münster, Institut für Botanik, Schlossgarten 3, D-48149 Münster, Germany.
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Nakayama M, Koshioka M, Matsui H, Ohara H, Mander LN, Leitch SK, Twitchin B, Kraft-Klaunzer P, Pharis RP, Yokota T. Endogenous gibberellins in immature seeds of Prunus persica L.: identification of GA(118), GA(119), GA(120), GA(121), GA(122) and GA(126). PHYTOCHEMISTRY 2001; 57:749-758. [PMID: 11397444 DOI: 10.1016/s0031-9422(01)00154-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The endogenous gibberellins in immature seeds of Prunus persica were analyzed by gas chromatography-mass spectrometry. Eleven known gibberellins, GA(3), GA(9), GA(17), GA(19), GA(30), GA(44), GA(61), GA(63), GA(87), GA(95) and GA(97) were identified. Additionally, several hitherto unknown gibberellins were detected and their putative structures were verified by synthesis of the authentic gibberellins. These gibberellins were then assigned trivial numbers, e.g. 1alpha-hydroxy GA(20) (GA(118)), 1alpha-hydroxy GA(9) (GA(119)), 1,2-didehydro GA(9) (GA(120)), 1,2-didehydro GA(70) (GA(121)), 1,2-didehydro GA(69) (GA(122)) and 1,2-didehydro GA(77) (GA(126)). GA(118) and GA(119) were the first 1alpha-hydroxy gibberellins identified from higher plants. The above profile of 1,2-didehydro gibberellins suggests that 1,2-dehydrogenation might occur prior to 3beta-hydroxylation in biosynthesis of GA(3), GA(30) and GA(87) in immature seeds of P. persica.
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Affiliation(s)
- M Nakayama
- Department of Genetics and Physiology, National Institute of Floricultural Science, 2-1 Fujimoto, Tsukuba, Ibaraki 305-8519, Japan
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Rojas MC, Hedden P, Gaskin P, Tudzynski B. The P450-1 gene of Gibberella fujikuroi encodes a multifunctional enzyme in gibberellin biosynthesis. Proc Natl Acad Sci U S A 2001; 98:5838-43. [PMID: 11320210 PMCID: PMC33300 DOI: 10.1073/pnas.091096298] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2001] [Accepted: 02/26/2001] [Indexed: 11/18/2022] Open
Abstract
Recent studies have shown that the genes of the gibberellin (GA) biosynthesis pathway in the fungus Gibberella fujikuroi are organized in a cluster of at least seven genes. P450-1 is one of four cytochrome P450 monooxygenase genes in this cluster. Disruption of the P450-1 gene in the GA-producing wild-type strain IMI 58289 led to total loss of GA production. Analysis of the P450-1-disrupted mutants indicated that GA biosynthesis was blocked immediately after ent-kaurenoic acid. The function of the P450-1 gene product was investigated further by inserting the gene into mutants of G. fujikuroi that lack the entire GA gene cluster; the gene was highly expressed under GA production conditions in the absence of the other GA-biosynthesis genes. Cultures of transformants containing P450-1 converted ent-[(14)C]kaurenoic acid efficiently into [(14)C]GA(14), indicating that P450-1 catalyzes four sequential steps in the GA-biosynthetic pathway: 7beta-hydroxylation, contraction of ring B by oxidation at C-6, 3beta-hydroxylation, and oxidation at C-7. The GA precursors ent-7alpha-hydroxy[(14)C]kaurenoic acid, [(14)C]GA(12)-aldehyde, and [(14)C]GA(12) were also converted to [(14)C]GA(14). In addition, there is an indication that P450-1 may also be involved in the formation of the kaurenolides and fujenoic acids, which are by-products of GA biosynthesis in G. fujikuroi. Thus, P450-1 displays remarkable multifunctionality and may be responsible for the formation of 12 products.
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Affiliation(s)
- M C Rojas
- Laboratorio de Bioorgánica, Departamento de Quimica, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile
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Sakamoto T, Kobayashi M, Itoh H, Tagiri A, Kayano T, Tanaka H, Iwahori S, Matsuoka M. Expression of a gibberellin 2-oxidase gene around the shoot apex is related to phase transition in rice. PLANT PHYSIOLOGY 2001; 125:1508-16. [PMID: 11244129 PMCID: PMC65628 DOI: 10.1104/pp.125.3.1508] [Citation(s) in RCA: 188] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2000] [Accepted: 12/20/2000] [Indexed: 05/18/2023]
Abstract
A major catabolic pathway for gibberellin (GA) is initiated by 2beta-hydroxylation, a reaction catalyzed by GA 2-oxidase. We have isolated and characterized a cDNA, designated Oryza sativa GA 2-oxidase 1 (OsGA2ox1) from rice (Oryza sativa L. cv Nipponbare) that encodes a GA 2-oxidase. The encoded protein, produced by heterologous expression in Escherichia coli, converted GA(1), GA(4), GA(9), GA(20), and GA(44) to the corresponding 2beta-hydroxylated products GA(8), GA(34), GA(51), GA(29), and GA(98), respectively. Ectopic expression of the OsGA2ox1 cDNA in transgenic rice inhibited stem elongation and the development of reproductive organs. These transgenic plants were deficient in endogenous GA(1). These results indicate that OsGA2ox1 encodes a GA 2-oxidase, which is functional not only in vitro but also in vivo. OsGA2ox1 was expressed in shoot apex and roots but not in leaves and stems. In situ hybridization analysis revealed that OsGA2ox1 mRNA was localized in a ring at the basal region of leaf primordia and young leaves. This ring-shaped expression around the shoot apex was drastically decreased after the phase transition from vegetative to reproductive growth. It was absent in the floral meristem, but it was still present in the lateral meristem that remained in the vegetative phase. These observations suggest that OsGA2ox1 controls the level of bioactive GAs in the shoot apical meristem; therefore, reduction in its expression may contribute to the early development of the inflorescence meristem.
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Affiliation(s)
- T Sakamoto
- Institute of Agriculture and Forestry, University of Tsukuba, Tsukuba 305-8572, Japan
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31
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Curtis IS, Ward DA, Thomas SG, Phillips AL, Davey MR, Power JB, Lowe KC, Croker SJ, Lewis MJ, Magness SL, Hedden P. Induction of dwarfism in transgenic Solanum dulcamara by over-expression of a gibberellin 20-oxidase cDNA from pumpkin. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2000; 23:329-338. [PMID: 10929126 DOI: 10.1046/j.1365-313x.2000.00784.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The gibberellin (GA) 20-oxidase (CmGA20ox1) from immature pumpkin seed produces predominantly inactive tricarboxylic acid GAs. We expressed CmGA20ox1 under the control of the CaMV 35S promoter in Solanum dulcamara to assess the usefulness of this gene for reducing GA content in transgenic plants. All transgenic plants obtained were semi-dwarfs with smaller, deep-green leaves and highly pigmented stems compared to the wild-type. Such transformants flowered earlier than the wild-type plants and produced more fruit and more seeds per fruit. The transgene was efficiently expressed, producing high levels of CmGA20ox1 transcript and protein. Furthermore, the concentration of GA(1) was reduced in leaves of the transformants to approximately 20% or less of that in the wild-type and to about 40% or less in stems. The concentrations of other 13-hydroxylated GAs were also reduced, except for the tricarboxylic acid, GA(17), which accumulated in the transformants due to 13-hydroxylation of GA(25). By contrast, the concentrations of non-13-hydroxylated GAs, GA(4) and GA(34), were not consistently reduced, indicating that the effect of expressing the pumpkin gene may not be predictable. Transcript abundance for a native GA 20-oxidase gene was higher in the leaves and stems of S. dulcamara transformed with the pumpkin gene than in wild-type, reflecting the feedback control of 20-oxidase gene expression that serves as a homeostatic mechanism for GAs.
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Affiliation(s)
- I S Curtis
- Plant Science Division, School of Biological Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
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Martin DN, Proebsting WM, Hedden P. The SLENDER gene of pea encodes a gibberellin 2-oxidase. PLANT PHYSIOLOGY 1999; 121:775-81. [PMID: 10557225 PMCID: PMC59439 DOI: 10.1104/pp.121.3.775] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/1999] [Accepted: 07/08/1999] [Indexed: 05/18/2023]
Abstract
The amount of active gibberellin (GA) in plant tissues is determined in part by its rate of catabolism through oxidation at C-2. In pea (Pisum sativum L.) seeds, GA 2-oxidation is controlled by the SLN (SLENDER) gene, a mutation of which produces seedlings characterized by a slender or hyper-elongated phenotype. We cloned a GA 2-oxidase cDNA from immature pea seeds by screening an expression library for enzyme activity. The clone contained a full-length open reading frame encoding a protein of 327 amino acids. Lysate of bacterial cultures expressing the protein converted the C(19)-GAs, GA(1), GA(4), GA(9), and GA(20) to the corresponding 2beta-hydroxy products. GA(9) and GA(20) were also converted to GA(51) and GA(29) catabolites, respectively. The gene appeared to be one member of a small family of GA 2-oxidases in pea. Transcript was found predominantly in roots, flowers, young fruits, and testae of seeds. The corresponding transcript from sln pea contained a point mutation and did not produce active enzyme when expressed heterologously. RFLP analysis of a seedling population segregating for SLN and sln alleles showed the homozygous mutant allele co-segregating with the characteristic slender phenotype. We conclude that SLN encodes GA 2-oxidase.
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Affiliation(s)
- D N Martin
- Department of Horticulture, Oregon State University, 4017 ALS, Corvallis, Oregon 97331-7304, USA
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Davis G, Kobayashi M, Phinney BO, Lange T, Croker SJ, Gaskin P, MacMillan J. Gibberellin Biosynthesis in Maize. Metabolic Studies with GA(15), GA(24), GA(25), GA(7), and 2,3-Dehydro-GA(9). PLANT PHYSIOLOGY 1999; 121:1037-1045. [PMID: 10557253 PMCID: PMC59468 DOI: 10.1104/pp.121.3.1037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
[17-(14)C]-Labeled GA(15), GA(24), GA(25), GA(7), and 2,3-dehydro-GA(9) were separately injected into normal, dwarf-1 (d1), and dwarf-5 (d5) seedlings of maize (Zea mays L.). Purified radioactive metabolites from the plant tissues were identified by full-scan gas chromatography-mass spectrometry and Kovats retention index data. The metabolites from GA(15) were GA(44), GA(19), GA(20), GA(113), and GA(15)-15,16-ene (artifact?). GA(24) was metabolized to GA(19), GA(20), and GA(17). The metabolites from GA(25) were GA(17), GA(25) 16alpha,17-H(2)-17-OH, and HO-GA(25) (hydroxyl position not determined). GA(7) was metabolized to GA(30), GA(3), isoGA(3) (artifact?), and trace amounts of GA(7)-diene-diacid (artifact?). 2,3-Dehydro-GA(9) was metabolized to GA(5), GA(7) (trace amounts), 2,3-dehydro-GA(10) (artifact?), GA(31), and GA(62). Our results provide additional in vivo evidence of a metabolic grid in maize (i.e. pathway convergence). The grid connects members of a putative, non-early 3,13-hydroxylation branch pathway to the corresponding members of the previously documented early 13-hydroxylation branch pathway. The inability to detect the sequence GA(12) --> GA(15) --> GA(24) --> GA(9) indicates that the non-early 3,13-hydroxylation pathway probably plays a minor role in the origin of bioactive gibberellins in maize.
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Affiliation(s)
- G Davis
- Molecular, Cell and Developmental Biology, University of California, Los Angeles, 405 Hilgard Avenue, Los Angeles, California 90095-1606
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Kang HG, Jun SH, Kim J, Kawaide H, Kamiya Y, An G. Cloning and molecular analyses of a gibberellin 20-oxidase gene expressed specifically in developing seeds of watermelon. PLANT PHYSIOLOGY 1999; 121:373-82. [PMID: 10517828 PMCID: PMC59399 DOI: 10.1104/pp.121.2.373] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
To understand the biosynthesis and functional role of gibberellins (GAs) in developing seeds, we isolated Cv20ox, a cDNA clone from watermelon (Citrullus lanatus) that shows significant amino acid homology with GA 20-oxidases. The complementary DNA clone was expressed in Escherichia coli as a fusion protein, which oxidized GA(12) at C-20 to the C(19) compound GA(9), a precursor of bioactive GAs. RNA-blot analysis showed that the Cv20ox gene was expressed specifically in developing seeds. The gene was strongly expressed in the integument tissues, and it was also expressed weakly in inner seed tissues. In parthenocarpic fruits induced by 1-(2-chloro-4-pyridyl)-3-phenylurea treatment, the expression pattern of Cv20ox did not change, indicating that the GA 20-oxidase gene is expressed primarily in the maternal cells of developing seeds. The promoter of Cv20ox was isolated and fused to the beta-glucuronidase (GUS) gene. In a transient expression system, beta-glucuronidase staining was detectable only in the integument tissues of developing watermelon seeds.
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Affiliation(s)
- H G Kang
- Department of Life Science, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
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Linnemannstöns P, Voss T, Hedden P, Gaskin P, Tudzynski B. Deletions in the gibberellin biosynthesis gene cluster of Gibberella fujikuroi by restriction enzyme-mediated integration and conventional transformation-mediated mutagenesis. Appl Environ Microbiol 1999; 65:2558-64. [PMID: 10347043 PMCID: PMC91378 DOI: 10.1128/aem.65.6.2558-2564.1999] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We induced mutants of Gibberella fujikuroi deficient in gibberellin (GA) biosynthesis by transformation-mediated mutagenesis with the vector pAN7-1. We recovered 24 GA-defective mutants in one of nine transformation experiments performed without the addition of a restriction enzyme. Each mutant had a similar Southern blot pattern, suggesting the integration of the vector into the same site. The addition of a restriction enzyme by restriction enzyme-mediated integration (REMI) significantly increased the transformation rate and the rate of single-copy integration events. Of 1,600 REMI transformants, two produced no GAs. Both mutants had multiple copies of the vector pAN7-1 and one had a Southern blot pattern similar to those of the 24 conventionally transformed GA-deficient mutants. Biochemical analysis of the two REMI mutants confirmed that they cannot produce ent-kaurene, the first specific intermediate of the GA pathway. Feeding the radioactively labelled precursors ent-kaurene and GA12-aldehyde followed by high-performance liquid chromatography and gas chromatography-mass spectrometry analysis showed that neither of these intermediates was converted to GAs in the mutants. Southern blot analysis and pulsed-field gel electrophoresis of the transformants using the bifunctional ent-copalyl diphosphate/ent-kaurene synthase gene (cps/ks) and the flanking regions as probes revealed a large deletion in the GA-deficient REMI transformants and in the GA-deficient transformants obtained by conventional insertional transformation. We conclude that transformation procedures with and without the addition of restriction enzymes can lead to insertion-mediated mutations and to deletions and chromosome translocations.
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Affiliation(s)
- P Linnemannstöns
- Institut für Botanik, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
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Thomas SG, Phillips AL, Hedden P. Molecular cloning and functional expression of gibberellin 2- oxidases, multifunctional enzymes involved in gibberellin deactivation. Proc Natl Acad Sci U S A 1999; 96:4698-703. [PMID: 10200325 PMCID: PMC16395 DOI: 10.1073/pnas.96.8.4698] [Citation(s) in RCA: 357] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A major catabolic pathway for the gibberellins (GAs) is initiated by 2beta-hydroxylation, a reaction catalyzed by 2-oxoglutarate-dependent dioxygenases. To isolate a GA 2beta-hydroxylase cDNA clone we used functional screening of a cDNA library from developing cotyledons of runner bean (Phaseolus coccineus L.) with a highly sensitive tritium-release assay for enzyme activity. The encoded protein, obtained by heterologous expression in Escherichia coli, converted GA9 to GA51 (2beta-hydroxyGA9) and GA51-catabolite, the latter produced from GA51 by further oxidation at C-2. The enzyme thus is multifunctional and is best described as a GA 2-oxidase. The recombinant enzyme also 2beta-hydroxylated other C19-GAs, although only GA9 and GA4 were converted to the corresponding catabolites. Three related cDNAs, corresponding to gene sequences present in Arabidopsis thaliana databases, also encoded functional GA 2-oxidases. Transcripts for two of the Arabidopsis genes were abundant in upper stems, flowers, and siliques, but the third transcript was not detected by Northern analysis. Transcript abundance for the two most highly expressed genes was lower in apices of the GA-deficient ga1-2 mutant of Arabidopsis than in wild-type plants and increased after treatment of the mutant with GA3. This up-regulation of GA 2-oxidase gene expression by GA contrasts GA-induced down-regulation of genes encoding the biosynthetic enzymes GA 20-oxidase and GA 3beta-hydroxylase. These mechanisms would serve to maintain the concentrations of biologically active GAs in plant tissues.
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Affiliation(s)
- S G Thomas
- Institute of Arable Crops Research (IACR)-Long Ashton Research Station, Department of Agricultural Sciences, University of Bristol, Long Ashton, Bristol BS41 9AF, United Kingdom
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Hedden P. Regulation of gibberellin biosynthesis. BIOCHEMISTRY AND MOLECULAR BIOLOGY OF PLANT HORMONES 1999. [DOI: 10.1016/s0167-7306(08)60487-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Williams J, Phillips AL, Gaskin P, Hedden P. Function and substrate specificity of the gibberellin 3beta-hydroxylase encoded by the Arabidopsis GA4 gene. PLANT PHYSIOLOGY 1998; 117:559-63. [PMID: 9625708 PMCID: PMC34975 DOI: 10.1104/pp.117.2.559] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/1997] [Accepted: 03/11/1998] [Indexed: 05/18/2023]
Abstract
cDNA corresponding to the GA4 gene of Arabidopsis thaliana L. (Heynh. ) was expressed in Escherichia coli, from which cell lysates converted [14C]gibberellin (GA)9 and [14C]GA20 to radiolabeled GA4 and GA1, respectively, thereby confirming that GA4 encodes a GA 3beta-hydroxylase. GA9 was the preferred substrate, with a Michaelis value of 1 microm compared with 15 microm for GA20. Hydroxylation of these GAs was regiospecific, with no indication of 2beta-hydroxylation or 2,3-desaturation. The capacity of the recombinant enzyme to hydroxylate a range of other GA substrates was investigated. In general, the preferred substrates contained a polar bridge between C-4 and C-10, and 13-deoxy GAs were preferred to their 13-hydroxylated analogs. Therefore, no activity was detected using GA12-aldehyde, GA12, GA19, GA25, GA53, or GA44 as the open lactone (20-hydroxy-GA53), whereas GA15, GA24, and GA44 were hydroxylated to GA37, GA36, and GA38, respectively. The open lactone of GA15 (20-hydroxy-GA12) was hydroxylated but less efficiently than GA15. In contrast to the free acid, GA25 19,20-anhydride was 3beta-hydroxylated to give GA13. 2,3-Didehydro-GA9 and GA5 were converted by recombinant GA4 to the corresponding epoxides 2, 3-oxido-GA9 and GA6.
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Affiliation(s)
- J Williams
- IACR-Long Ashton Research Station, Department of Agricultural Sciences, University of Bristol, Long Ashton, Bristol BS41 9AF, United Kingdom
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Martin DN, Proebsting WM, Hedden P. Mendel's dwarfing gene: cDNAs from the Le alleles and function of the expressed proteins. Proc Natl Acad Sci U S A 1997; 94:8907-11. [PMID: 9238076 PMCID: PMC23192 DOI: 10.1073/pnas.94.16.8907] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/1997] [Accepted: 05/27/1997] [Indexed: 02/04/2023] Open
Abstract
The major gibberellin (GA) controlling stem elongation in pea (Pisum sativum L.) is GA1, which is formed from GA20 by 3beta-hydroxylation. This step, which limits GA1 biosynthesis in pea, is controlled by the Le locus, one of the original Mendelian loci. Mutations in this locus result in dwarfism. We have isolated cDNAs encoding a GA 3beta-hydroxylase from lines of pea carrying the Le, le, le-3, and led alleles. The cDNA sequences from le and le-3 each contain a base substitution resulting in single amino acid changes relative to the sequence from Le. The cDNA sequence from led, a mutant derived from an le line, contains both the le "mutation" and a single-base deletion, which causes a shift in reading frame and presumably a null mutation. cDNAs from each line were expressed in Escherichia coli. The expression product for the clone from Le converted GA9 to GA4, and GA20 to GA1, with Km values of 1.5 microM and 13 microM, respectively. The amino acid substitution in the clone from le increased Km for GA9 100-fold and reduced conversion of GA20 to almost nil. Expression products from le and le-3 possessed similar levels of 3beta-hydroxylase activity, and the expression product from led was inactive. Our results suggest that the 3beta-hydroxylase cDNA is encoded by Le. Le transcript is expressed in roots, shoots, and cotyledons of germinating pea seedlings, in internodes and leaves of established seedlings, and in developing seeds.
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Affiliation(s)
- D N Martin
- Department of Horticulture and Center for Gene Research and Biotechnology, Oregon State University, Corvallis, OR 97331, USA
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Lange T, Robatzek S, Frisse A. Cloning and expression of a gibberellin 2 beta,3 beta-hydroxylase cDNA from pumpkin endosperm. THE PLANT CELL 1997; 9:1459-67. [PMID: 9286114 PMCID: PMC157011 DOI: 10.1105/tpc.9.8.1459] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A cDNA expression library in lambda MOSEIox derived from poly(A)+ RNA from pumpkin endosperm was screened immunologically with a polyclonal antibody raised against partially purified gibberellin (GA) 2 beta,3 beta-hydroxylase from pumpkin endosperm. A recombinant fusion protein encoded by a selected positive clone catalyzed 3 beta-hydroxylation of GA15, GA24, GA25, and GA17 and of GA12-aldehyde, GA12, GA9, and GA20, albeit less efficiently. The fusion protein also catalyzed 2 beta-hydroxylation of the C20 GAS GA25, GA13, and, as identified putatively, GA28. The full-length clone contains an open reading frame of 1041 nucleotides encoding 346 amino acid residues with a predicted molecular weight of 38,992 and pI of 7.2. Transcript levels of this gene and of the previously cloned GA 7-oxidase and 20-oxidase genes from pumpkin endosperm rose until day 2 after the start of imbibition of the mature seeds, but only at one-two hundredth to one-six thousandth of the level found in the endosperm, as determined by quantitative reverse transcriptase-polymerase chain reaction. In contrast, GA 7-oxidase, 20-oxidase, and 3 beta-hydroxylase enzyme activities were present in cell-free systems prepared from embryos of mature seeds and decreased after imbibition.
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Affiliation(s)
- T Lange
- Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Universität Göttingen, Germany.
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Lange T. Cloning gibberellin dioxygenase genes from pumpkin endosperm by heterologous expression of enzyme activities in Escherichia coli. Proc Natl Acad Sci U S A 1997; 94:6553-8. [PMID: 9177256 PMCID: PMC21088 DOI: 10.1073/pnas.94.12.6553] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Gibberellin (GA) plant hormones are biosynthesized via complex pathways, the final steps of which are catalyzed by 2-oxoglutarate-dependent dioxygenases. Here, the cloning of two such enzymes, the GA 7-oxidase and the GA 20-oxidase, is reported using a novel approach, namely, by screening for GA dioxygenase activities expressed as T7 gene 10 fusion proteins in recombinant Escherichia coli. In vitro translation products of mRNA from endosperm of immature pumpkin seeds contained three GA dioxygenase activities, including 7-oxidase, 20-oxidase, and 3beta-hydroxylase. A cDNA expression library was prepared from the endosperm mRNA in lambdaMOSElox. An aliquot of the amplified library was converted to plasmids in vivo and used for transformation of E. coli BL21(DE3), which thereafter expressed recombinant fusion proteins containing 7-oxidase, 20-oxidase, and 3beta-hydroxylase activities. By screening for specific GA dioxygenase expression, clones harboring 7-oxidase and 20-oxidase cDNA were isolated. The ORF of the 7-oxidase cDNA is 945 bp long, encoding for 314 amino acid residues with a calculated Mr of 35,712 and pI of 5.7. Recombinant GA 7-oxidase oxidizes GA12-aldehyde to GA12 and GA14-aldehyde to GA14. Evidence was obtained for further metabolism of GA12 by the 7-oxidase to four products, two of which are monohydroxylated GA12. The ORF of the 20-oxidase is-apart from seven changes, resulting in four amino acid substitutions-identical to the 20-oxidase cDNA previously cloned from pumpkin cotyledon mRNA; both 20-oxidases have the same catalytic properties.
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Affiliation(s)
- T Lange
- Pflanzenphysiologisches Institut und Botanischer Garten der Universität Göttingen, Untere Karspüle 2, D-37073 Göttingen, Germany.
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Abstract
The recent impressive progress in research on gibberellin (GA) biosynthesis has resulted primarily from cloning of genes encoding biosynthetic enzymes and studies with GA-deficient and GA-insensitive mutants. Highlights include the cloning of ent-copalyl diphosphate synthase and ent-kaurene synthase (formally ent-kaurene synthases A and B) and the demonstration that the former is targeted to the plastid; the finding that the Dwarf-3 gene of maize encodes a cytochrome P450, although of unknown function; and the cloning of GA 20-oxidase and 3beta-hydroxylase genes. The availability of cDNA and genomic clones for these enzymes is enabling the mechanisms by which GA concentrations are regulated by environmental and endogenous factors to be studied at the molecular level. For example, it has been shown that transcript levels for GA 20-oxidase and 3beta-hydroxylase are subject to feedback regulation by GA action and, in the case of the GA 20-oxidase, are regulated by light. Also discussed is other new information, particularly from mutants, that has added to our understanding of the biosynthetic pathway, the enzymes, and their regulation and tissue localization.
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Affiliation(s)
- Peter Hedden
- IACR-Long Ashton Research Station, Department of Agricultural Science, University of Bristol, Bristol, BS18 9AF, United Kingdom, Frontier Research Program, The Institute of Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako-shi, Saitama 351-01, Japan
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