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Ndreca B, Huttly A, Bibi S, Bayon C, Lund G, Ham J, Alarcón-Reverte R, Addy J, Tarkowská D, Pearce S, Hedden P, Thomas SG, Phillips AL. Stacked mutations in wheat homologues of rice SEMI-DWARF1 confer a novel semi-dwarf phenotype. BMC Plant Biol 2024; 24:384. [PMID: 38724935 PMCID: PMC11080193 DOI: 10.1186/s12870-024-05098-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Accepted: 05/03/2024] [Indexed: 05/13/2024]
Abstract
BACKGROUND Semi-dwarfing alleles are used widely in cereals to confer improved lodging resistance and assimilate partitioning. The most widely deployed semi-dwarfing alleles in rice and barley encode the gibberellin (GA)-biosynthetic enzyme GA 20-OXIDASE2 (GA20OX2). The hexaploid wheat genome carries three homoeologous copies of GA20OX2, and because of functional redundancy, loss-of-function alleles of a single homoeologue would not be selected in wheat breeding programmes. Instead, approximately 70% of wheat cultivars carry gain-of-function mutations in REDUCED HEIGHT 1 (RHT1) genes that encode negative growth regulators and are degraded in response to GA. Semi-dwarf Rht-B1b or Rht-D1b alleles encode proteins that are insensitive to GA-mediated degradation. However, because RHT1 is expressed ubiquitously these alleles have pleiotropic effects that confer undesirable traits in some environments. RESULTS We have applied reverse genetics to combine loss-of-function alleles in all three homoeologues of wheat GA20OX2 and its paralogue GA20OX1 and evaluated their performance in three years of field trials. ga20ox1 mutants exhibited a mild height reduction (approximately 3%) suggesting GA20OX1 plays a minor role in stem elongation in wheat. ga20ox2 mutants have reduced GA1 content and are 12-32% shorter than their wild-type segregants, comparable to the effect of the Rht-D1b 'Green Revolution' allele. The ga20ox2 mutants showed no significant negative effects on yield components in the spring wheat variety 'Cadenza'. CONCLUSIONS Our study demonstrates that chemical mutagenesis can expand genetic variation in polyploid crops to uncover novel alleles despite the difficulty in identifying appropriate mutations for some target genes and the negative effects of background mutations. Field experiments demonstrate that mutations in GA20OX2 reduce height in wheat, but it will be necessary to evaluate the effect of these alleles in different genetic backgrounds and environments to determine their value in wheat breeding as alternative semi-dwarfing alleles.
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Affiliation(s)
- Barbora Ndreca
- Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Alison Huttly
- Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Sajida Bibi
- Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
- Nuclear Institute for Agriculture and Biology, Faisalabad, Punjab, Pakistan
| | - Carlos Bayon
- Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - George Lund
- Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Joshua Ham
- Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | | | - John Addy
- Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Danuše Tarkowská
- Laboratory of Growth Regulators, Institute of Experimental Botany, Czech Academy of Sciences and Palacky University, Šlechtitelů 27, Olomouc, CZ 78371, Czech Republic
| | - Stephen Pearce
- Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK.
| | - Peter Hedden
- Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
- Laboratory of Growth Regulators, Institute of Experimental Botany, Czech Academy of Sciences and Palacky University, Šlechtitelů 27, Olomouc, CZ 78371, Czech Republic
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Shani E, Hedden P, Sun TP. Highlights in gibberellin research: A tale of the dwarf and the slender. Plant Physiol 2024; 195:111-134. [PMID: 38290048 PMCID: PMC11060689 DOI: 10.1093/plphys/kiae044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/30/2023] [Accepted: 11/06/2023] [Indexed: 02/01/2024]
Abstract
It has been almost a century since biologically active gibberellin (GA) was isolated. Here, we give a historical overview of the early efforts in establishing the GA biosynthesis and catabolism pathway, characterizing the enzymes for GA metabolism, and elucidating their corresponding genes. We then highlight more recent studies that have identified the GA receptors and early GA signaling components (DELLA repressors and F-box activators), determined the molecular mechanism of DELLA-mediated transcription reprograming, and revealed how DELLAs integrate multiple signaling pathways to regulate plant vegetative and reproductive development in response to internal and external cues. Finally, we discuss the GA transporters and their roles in GA-mediated plant development.
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Affiliation(s)
- Eilon Shani
- School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv 69978, Israel
| | - Peter Hedden
- Laboratory of Growth Regulators, Institute of Experimental Botany and Palacky University, 78371 Olomouc, Czech Republic
- Sustainable Soils and Crops, Rothamsted Research, Harpenden AL5 2JQ, UK
| | - Tai-ping Sun
- Department of Biology, Duke University, Durham, NC 27708, USA
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Ptošková K, Szecówka M, Jaworek P, Tarkowská D, Petřík I, Pavlović I, Novák O, Thomas SG, Phillips AL, Hedden P. Changes in the concentrations and transcripts for gibberellins and other hormones in a growing leaf and roots of wheat seedlings in response to water restriction. BMC Plant Biol 2022; 22:284. [PMID: 35676624 PMCID: PMC9178827 DOI: 10.1186/s12870-022-03667-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 05/23/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Bread wheat (Triticum aestivum) is a major source of nutrition globally, but yields can be seriously compromised by water limitation. Redistribution of growth between shoots and roots is a common response to drought, promoting plant survival, but reducing yield. Gibberellins (GAs) are necessary for shoot and root elongation, but roots maintain growth at lower GA concentrations compared with shoots, making GA a suitable hormone for mediating this growth redistribution. In this study, the effect of progressive drought on GA content was determined in the base of the 4th leaf and root tips of wheat seedlings, containing the growing regions, as well as in the remaining leaf and root tissues. In addition, the contents of other selected hormones known to be involved in stress responses were determined. Transcriptome analysis was performed on equivalent tissues and drought-associated differential expression was determined for hormone-related genes. RESULTS After 5 days of applying progressive drought to 10-day old seedlings, the length of leaf 4 was reduced by 31% compared with watered seedlings and this was associated with significant decreases in the concentrations of bioactive GA1 and GA4 in the leaf base, as well as of their catabolites and precursors. Root length was unaffected by drought, while GA concentrations were slightly, but significantly higher in the tips of droughted roots compared with watered plants. Transcripts for the GA-inactivating gene TaGA2ox4 were elevated in the droughted leaf, while those for several GA-biosynthesis genes were reduced by drought, but mainly in the non-growing region. In response to drought the concentrations of abscisic acid, cis-zeatin and its riboside increased in all tissues, indole-acetic acid was unchanged, while trans-zeatin and riboside, jasmonate and salicylic acid concentrations were reduced. CONCLUSIONS Reduced leaf elongation and maintained root growth in wheat seedlings subjected to progressive drought were associated with attenuated and increased GA content, respectively, in the growing regions. Despite increased TaGA2ox4 expression, lower GA levels in the leaf base of droughted plants were due to reduced biosynthesis rather than increased catabolism. In contrast to GA, the other hormones analysed responded to drought similarly in the leaf and roots, indicating organ-specific differential regulation of GA metabolism in response to drought.
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Affiliation(s)
- Klára Ptošková
- Laboratory of Growth Regulators, Institute of Experimental Botany, Czech Academy of Sciences and Palacky University, Šlechtitelů 27, CZ-78371, Olomouc, Czech Republic
| | - Marek Szecówka
- Laboratory of Growth Regulators, Institute of Experimental Botany, Czech Academy of Sciences and Palacky University, Šlechtitelů 27, CZ-78371, Olomouc, Czech Republic
| | - Pavel Jaworek
- Laboratory of Growth Regulators, Institute of Experimental Botany, Czech Academy of Sciences and Palacky University, Šlechtitelů 27, CZ-78371, Olomouc, Czech Republic
| | - Danuše Tarkowská
- Laboratory of Growth Regulators, Institute of Experimental Botany, Czech Academy of Sciences and Palacky University, Šlechtitelů 27, CZ-78371, Olomouc, Czech Republic
| | - Ivan Petřík
- Laboratory of Growth Regulators, Institute of Experimental Botany, Czech Academy of Sciences and Palacky University, Šlechtitelů 27, CZ-78371, Olomouc, Czech Republic
| | - Iva Pavlović
- Laboratory of Growth Regulators, Institute of Experimental Botany, Czech Academy of Sciences and Palacky University, Šlechtitelů 27, CZ-78371, Olomouc, Czech Republic
| | - Ondřej Novák
- Laboratory of Growth Regulators, Institute of Experimental Botany, Czech Academy of Sciences and Palacky University, Šlechtitelů 27, CZ-78371, Olomouc, Czech Republic
| | - Stephen G Thomas
- Department of Plant Science, Rothamsted Research, Harpenden, AL5 2JQ, UK
| | - Andrew L Phillips
- Department of Plant Science, Rothamsted Research, Harpenden, AL5 2JQ, UK
| | - Peter Hedden
- Laboratory of Growth Regulators, Institute of Experimental Botany, Czech Academy of Sciences and Palacky University, Šlechtitelů 27, CZ-78371, Olomouc, Czech Republic.
- Department of Plant Science, Rothamsted Research, Harpenden, AL5 2JQ, UK.
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Camut L, Gallova B, Jilli L, Sirlin-Josserand M, Carrera E, Sakvarelidze-Achard L, Ruffel S, Krouk G, Thomas SG, Hedden P, Phillips AL, Davière JM, Achard P. Nitrate signaling promotes plant growth by upregulating gibberellin biosynthesis and destabilization of DELLA proteins. Curr Biol 2021; 31:4971-4982.e4. [PMID: 34614391 DOI: 10.1016/j.cub.2021.09.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 08/13/2021] [Accepted: 09/08/2021] [Indexed: 10/20/2022]
Abstract
Nitrate, one of the main nitrogen (N) sources for crops, acts as a nutrient and key signaling molecule coordinating gene expression, metabolism, and various growth processes throughout the plant life cycle. It is widely accepted that nitrate-triggered developmental programs cooperate with hormone synthesis and transport to finely adapt plant architecture to N availability. Here, we report that nitrate, acting through its signaling pathway, promotes growth in Arabidopsis and wheat, in part by modulating the accumulation of gibberellin (GA)-regulated DELLA growth repressors. We show that nitrate reduces the abundance of DELLAs by increasing GA contents through activation of GA metabolism gene expression. Consistently, the growth restraint conferred by nitrate deficiency is partially rescued in global-DELLA mutant that lacks all DELLAs. At the cellular level, we show that nitrate enhances both cell proliferation and elongation in a DELLA-dependent and -independent manner, respectively. Our findings establish a connection between nitrate and GA signaling pathways that allow plants to adapt their growth to nitrate availability.
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Affiliation(s)
- Lucie Camut
- Institut de Biologie Moléculaire des Plantes, CNRS, University of Strasbourg, 67084 Strasbourg, France
| | - Barbora Gallova
- Plant Science Department, Rothamsted Research, Harpenden AL5 2JQ, UK
| | - Lucas Jilli
- Institut de Biologie Moléculaire des Plantes, CNRS, University of Strasbourg, 67084 Strasbourg, France
| | - Mathilde Sirlin-Josserand
- Institut de Biologie Moléculaire des Plantes, CNRS, University of Strasbourg, 67084 Strasbourg, France
| | - Esther Carrera
- Instituto de Biología Molecular y Celular de Plantas, CSIC-UPV, 46022 Valencia, Spain
| | - Lali Sakvarelidze-Achard
- Institut de Biologie Moléculaire des Plantes, CNRS, University of Strasbourg, 67084 Strasbourg, France
| | - Sandrine Ruffel
- BPMP, Univ Montpellier, CNRS, INRAE, Montpellier SupAgro, Montpellier, France
| | - Gabriel Krouk
- BPMP, Univ Montpellier, CNRS, INRAE, Montpellier SupAgro, Montpellier, France
| | - Stephen G Thomas
- Plant Science Department, Rothamsted Research, Harpenden AL5 2JQ, UK
| | - Peter Hedden
- Plant Science Department, Rothamsted Research, Harpenden AL5 2JQ, UK; Laboratory of Growth Regulators, Institute of Experimental Botany and Palacky University, 78371 Olomouc, Czech Republic
| | - Andrew L Phillips
- Plant Science Department, Rothamsted Research, Harpenden AL5 2JQ, UK
| | - Jean-Michel Davière
- Institut de Biologie Moléculaire des Plantes, CNRS, University of Strasbourg, 67084 Strasbourg, France
| | - Patrick Achard
- Institut de Biologie Moléculaire des Plantes, CNRS, University of Strasbourg, 67084 Strasbourg, France.
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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. New Phytol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Wang X, Shen J, Hedden P, Phillips AL, Thomas SG, Ge Y, Ashton RW, Whalley WR. Wheat growth responses to soil mechanical impedance are dependent on phosphorus supply. Soil Tillage Res 2021; 205:104754. [PMID: 33390631 PMCID: PMC7729824 DOI: 10.1016/j.still.2020.104754] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 07/08/2020] [Accepted: 07/21/2020] [Indexed: 06/12/2023]
Abstract
Increased mechanical impedance induced by soil drying or compaction causes reduction in plant growth and crop yield. However, how mechanical impedance interacts with nutrient stress has been largely unknown. Here, we investigated the effect of mechanical impedance on the growth of wheat seedlings under contrasting phosphorus (P) supply in a sand culture system which allows the mechanical impedance to be independent of water and nutrient availability. Two wheat genotypes containing the Rht-B1a (tall) or Rht-B1c (gibberellin-insensitive dwarf) alleles in the Cadenza background were used and their shoot and root traits were determined. Mechanical impedance caused a significant reduction in plant growth under sufficient P supply, including reduced shoot and root biomass, leaf area and total root length. By contrast, under low P supply, mechanical impedance did not affect biomass, tiller number, leaf length, and nodal root number in both wheat genotypes, indicating that the magnitude of the growth restriction imposed by mechanical impedance was dependent on P supply. The interaction effect between mechanical impedance and P level was significant on most plant traits except for axial and lateral root length, suggesting an evident physical and nutritional interaction. Our findings provide valuable insights into the integrated effects of plants in response to both soil physical and nutritional stresses. Understanding the response patterns is critical for optimizing soil tillage and nutrient management in the field.
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Affiliation(s)
- Xin Wang
- Department of Plant Nutrition, College of Resources and Environmental Sciences, Key Laboratory of Plant-Soil Interactions, MoE, National Academy of Agriculture Green Development, China Agricultural University, Beijing, 100193, PR China
- Rothamsted Research, West Common, Harpenden, AL5 2JQ, UK
| | - Jianbo Shen
- Department of Plant Nutrition, College of Resources and Environmental Sciences, Key Laboratory of Plant-Soil Interactions, MoE, National Academy of Agriculture Green Development, China Agricultural University, Beijing, 100193, PR China
| | - Peter Hedden
- Rothamsted Research, West Common, Harpenden, AL5 2JQ, UK
- Laboratory of Growth Regulators, Czech Academy of Sciences, Institute of Experimental Botany & Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
| | | | | | - Yaoxiang Ge
- Rothamsted Research, West Common, Harpenden, AL5 2JQ, UK
- College of Biology and Pharmacy, Yulin Normal University, Yulin, 537000, PR China
| | - Rhys W. Ashton
- Rothamsted Research, West Common, Harpenden, AL5 2JQ, UK
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Abstract
Gibberellins are produced by all vascular plants and several fungal and bacterial species that associate with plants as pathogens or symbionts. In the 60 years since the first experiments on the biosynthesis of gibberellic acid in the fungus Fusarium fujikuroi, research on gibberellin biosynthesis has advanced to provide detailed information on the pathways, biosynthetic enzymes and their genes in all three kingdoms, in which the production of the hormones evolved independently. Gibberellins function as hormones in plants, affecting growth and differentiation in organs in which their concentration is very tightly regulated. Current research in plants is focused particularly on the regulation of gibberellin biosynthesis and inactivation by developmental and environmental cues, and there is now considerable information on the molecular mechanisms involved in these processes. There have also been recent advances in understanding gibberellin transport and distribution and their relevance to plant development. This review describes our current understanding of gibberellin metabolism and its regulation, highlighting the more recent advances in this field.
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Affiliation(s)
- Peter Hedden
- Laboratory of Growth Regulators, Palack� University & Institute of Experimental Botany of the Czech Academy of Sciences, Šlechtitelů 27, 78371 Olomouc, Czech Republic
- Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK
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8
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Regnault T, Davière JM, Wild M, Sakvarelidze-Achard L, Heintz D, Bergua EC, Diaz IL, Gong F, Hedden P, Achard P. Author Correction: The gibberellin precursor GA 12 acts as a long-distance growth signal in Arabidopsis. Nat Plants 2020; 6:1503. [PMID: 33154557 DOI: 10.1038/s41477-020-00797-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Affiliation(s)
- Thomas Regnault
- Institut de Biologie Moléculaire des Plantes, UPR2357, associé avec l'Université de Strasbourg, Strasbourg, 67084, France
- Department of Plant Systems Biology, Freising, 85354, Germany
| | - Jean-Michel Davière
- Institut de Biologie Moléculaire des Plantes, UPR2357, associé avec l'Université de Strasbourg, Strasbourg, 67084, France
| | - Michael Wild
- Institut de Biologie Moléculaire des Plantes, UPR2357, associé avec l'Université de Strasbourg, Strasbourg, 67084, France
- University of Freiburg, Freiburg, 79104, Germany
| | - Lali Sakvarelidze-Achard
- Institut de Biologie Moléculaire des Plantes, UPR2357, associé avec l'Université de Strasbourg, Strasbourg, 67084, France
| | - Dimitri Heintz
- Institut de Biologie Moléculaire des Plantes, UPR2357, associé avec l'Université de Strasbourg, Strasbourg, 67084, France
| | - Esther Carrera Bergua
- Instituto de Biología Molecular y Celular de Plantas, CSIC-UPV, Valencia, 46022, Spain
| | - Isabel Lopez Diaz
- Instituto de Biología Molecular y Celular de Plantas, CSIC-UPV, Valencia, 46022, Spain
| | - Fan Gong
- Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
- Home Office Science - Centre for Applied Science and Technology, Woodcock Hill, Sandridge, St Albans, Hertfordshire, AL4 9HQ, UK
| | - Peter Hedden
- Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Patrick Achard
- Institut de Biologie Moléculaire des Plantes, UPR2357, associé avec l'Université de Strasbourg, Strasbourg, 67084, France.
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Affiliation(s)
- Peter Hedden
- Laboratory of Growth Regulators, Czech Academy of Sciences, Institute of Experimental Botany and Palacký University, Olomouc, Czech Republic.
- Plant Science Department, Rothamsted Research, Harpenden, UK.
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10
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Plackett ARG, Powers SJ, Phillips AL, Wilson ZA, Hedden P, Thomas SG. The early inflorescence of Arabidopsis thaliana demonstrates positional effects in floral organ growth and meristem patterning. Plant Reprod 2018; 31:171-191. [PMID: 29264708 PMCID: PMC5940708 DOI: 10.1007/s00497-017-0320-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 12/11/2017] [Indexed: 05/04/2023]
Abstract
Linear modelling approaches detected significant gradients in organ growth and patterning across early flowers of the Arabidopsis inflorescence and uncovered evidence of new roles for gibberellin in floral development. Most flowering plants, including the genetic model Arabidopsis thaliana, produce multiple flowers in sequence from a reproductive shoot apex to form a flower spike (inflorescence). The development of individual flowers on an Arabidopsis inflorescence has typically been considered as highly stereotypical and uniform, but this assumption is contradicted by the existence of mutants with phenotypes visible in early flowers only. This phenomenon is demonstrated by mutants partially impaired in the biosynthesis of the phytohormone gibberellin (GA), in which floral organ growth is retarded in the first flowers to be produced but has recovered spontaneously by the 10th flower. We presently lack systematic data from multiple flowers across the Arabidopsis inflorescence to explain such changes. Using mutants of the GA 20-OXIDASE (GA20ox) GA biosynthesis gene family to manipulate endogenous GA levels, we investigated the dynamics of changing floral organ growth across the early Arabidopsis inflorescence (flowers 1-10). Modelling of floral organ lengths identified a significant, GA-independent gradient of increasing stamen length relative to the pistil in the wild-type inflorescence that was separable from other, GA-dependent effects. It was also found that the first flowers exhibited unstable organ patterning in contrast to later flowers and that this instability was prolonged by exogenous GA treatment. These findings indicate that the development of individual flowers is influenced by hitherto unknown factors acting across the inflorescence and also suggest novel functions for GA in floral patterning.
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Affiliation(s)
- Andrew R G Plackett
- Department of Plant Sciences, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK.
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
| | - Stephen J Powers
- Department of Computational and Analytical Sciences, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Andy L Phillips
- Department of Plant Sciences, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Zoe A Wilson
- School of Biosciences, University of Nottingham, Loughborough, Leicestershire, LE12 5RD, UK
| | - Peter Hedden
- Department of Plant Sciences, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
- Laboratory of Growth Regulators, Palacký University and Institute of Experimental Botany AS CR, Šlechtitelů 27, Olomouc, 783 71, Czech Republic
| | - Stephen G Thomas
- Department of Plant Sciences, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
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Nett RS, Montanares M, Marcassa A, Lu X, Nagel R, Charles TC, Hedden P, Rojas MC, Peters RJ. Elucidation of gibberellin biosynthesis in bacteria reveals convergent evolution. Nat Chem Biol 2016; 13:69-74. [PMID: 27842068 DOI: 10.1038/nchembio.2232] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 09/23/2016] [Indexed: 12/22/2022]
Abstract
Gibberellins (GAs) are crucial phytohormones involved in many aspects of plant growth and development, including plant-microbe interactions, which has led to GA production by plant-associated fungi and bacteria as well. While the GA biosynthetic pathways in plants and fungi have been elucidated and found to have arisen independently through convergent evolution, little has been uncovered about GA biosynthesis in bacteria. Some nitrogen-fixing, symbiotic, legume-associated rhizobia, including Bradyrhizobium japonicum-the symbiont of soybean-and Sinorhizobium fredii-a broad-host-nodulating species-contain a putative GA biosynthetic operon, or gene cluster. Through functional characterization of five unknown genes, we demonstrate that this operon encodes the enzymes necessary to produce GA9, thereby elucidating bacterial GA biosynthesis. The distinct nature of these enzymes indicates that bacteria have independently evolved a third biosynthetic pathway for GA production. Furthermore, our results also reveal a central biochemical logic that is followed in all three convergently evolved GA biosynthetic pathways.
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Affiliation(s)
- Ryan S Nett
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, USA
| | - Mariana Montanares
- Laboratorio de Bioorgánica, Departamento de Química, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Ariana Marcassa
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Xuan Lu
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, USA
| | - Raimund Nagel
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, USA
| | - Trevor C Charles
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Peter Hedden
- Rothamsted Research, Harpenden, Hertfordshire, UK
| | - Maria Cecilia Rojas
- Laboratorio de Bioorgánica, Departamento de Química, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Reuben J Peters
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, USA
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Gao W, Hodgkinson L, Jin K, Watts CW, Ashton RW, Shen J, Ren T, Dodd IC, Binley A, Phillips AL, Hedden P, Hawkesford MJ, Whalley WR. Deep roots and soil structure. Plant Cell Environ 2016; 39:1662-8. [PMID: 26650587 PMCID: PMC4950291 DOI: 10.1111/pce.12684] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 11/10/2015] [Accepted: 11/13/2015] [Indexed: 05/18/2023]
Abstract
In this opinion article we examine the relationship between penetrometer resistance and soil depth in the field. Assuming that root growth is inhibited at penetrometer resistances > 2.5 MPa, we conclude that in most circumstances the increases in penetrometer resistance with depth are sufficiently great to confine most deep roots to elongating in existing structural pores. We suggest that deep rooting is more likely related to the interaction between root architecture and soil structure than it is to the ability of a root to deform strong soil. Although the ability of roots to deform strong soil is an important trait, we propose it is more closely related to root exploration of surface layers than deep rooting.
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Affiliation(s)
- W Gao
- China Agricultural University, Beijing, 100193, China
| | - L Hodgkinson
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK
| | - K Jin
- Huazhong Agricultural University, Hongshan District, Wuhan, 430070, China
| | - C W Watts
- Rothamsted Research, West Common, Harpenden, St. Albans, AL5 2JQ, UK
| | - R W Ashton
- Rothamsted Research, West Common, Harpenden, St. Albans, AL5 2JQ, UK
| | - J Shen
- China Agricultural University, Beijing, 100193, China
| | - T Ren
- China Agricultural University, Beijing, 100193, China
| | - I C Dodd
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK
| | - A Binley
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK
| | - A L Phillips
- Rothamsted Research, West Common, Harpenden, St. Albans, AL5 2JQ, UK
| | - P Hedden
- Rothamsted Research, West Common, Harpenden, St. Albans, AL5 2JQ, UK
| | - M J Hawkesford
- Rothamsted Research, West Common, Harpenden, St. Albans, AL5 2JQ, UK
| | - W R Whalley
- Rothamsted Research, West Common, Harpenden, St. Albans, AL5 2JQ, UK
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13
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Liu Z, Boachon B, Lugan R, Tavares R, Erhardt M, Mutterer J, Demais V, Pateyron S, Brunaud V, Ohnishi T, Pencik A, Achard P, Gong F, Hedden P, Werck-Reichhart D, Renault H. A Conserved Cytochrome P450 Evolved in Seed Plants Regulates Flower Maturation. Mol Plant 2015; 8:1751-1765. [PMID: 26388305 DOI: 10.1016/j.molp.2015.09.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 08/31/2015] [Accepted: 09/05/2015] [Indexed: 06/05/2023]
Abstract
Global inspection of plant genomes identifies genes maintained in low copies across taxa and under strong purifying selection, which are likely to have essential functions. Based on this rationale, we investigated the function of the low-duplicated CYP715 cytochrome P450 gene family that appeared early in seed plants and evolved under strong negative selection. Arabidopsis CYP715A1 showed a restricted tissue-specific expression in the tapetum of flower buds and in the anther filaments upon anthesis. cyp715a1 insertion lines showed a strong defect in petal development, and transient alteration of pollen intine deposition. Comparative expression analysis revealed the downregulated expression of genes involved in pollen development, cell wall biogenesis, hormone homeostasis, and floral sesquiterpene biosynthesis, especially TPS21 and several key genes regulating floral development such as MYB21, MYB24, and MYC2. Accordingly, floral sesquiterpene emission was suppressed in the cyp715a1 mutants. Flower hormone profiling, in addition, indicated a modification of gibberellin homeostasis and a strong disturbance of the turnover of jasmonic acid derivatives. Petal growth was partially restored by the active gibberellin GA3 or the functional analog of jasmonoyl-isoleucine, coronatine. CYP715 appears to function as a key regulator of flower maturation, synchronizing petal expansion and volatile emission. It is thus expected to be an important determinant of flower-insect interaction.
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Affiliation(s)
- Zhenhua Liu
- Institute of Plant Molecular Biology, Centre National de la Recherche Scientifique (CNRS), University of Strasbourg, 67084 Strasbourg, France
| | - Benoît Boachon
- Institute of Plant Molecular Biology, Centre National de la Recherche Scientifique (CNRS), University of Strasbourg, 67084 Strasbourg, France
| | - Raphaël Lugan
- Institute of Plant Molecular Biology, Centre National de la Recherche Scientifique (CNRS), University of Strasbourg, 67084 Strasbourg, France
| | - Raquel Tavares
- Laboratoire de Biométrie et Biologie Évolutive, Université Lyon 1, CNRS, 69622 Villeurbanne, France
| | - Mathieu Erhardt
- Institute of Plant Molecular Biology, Centre National de la Recherche Scientifique (CNRS), University of Strasbourg, 67084 Strasbourg, France
| | - Jérôme Mutterer
- Institute of Plant Molecular Biology, Centre National de la Recherche Scientifique (CNRS), University of Strasbourg, 67084 Strasbourg, France
| | - Valérie Demais
- Plateforme d'Imagerie In Vitro, IFR 37 de Neurosciences, 67084 Strasbourg, France
| | - Stéphanie Pateyron
- Transcriptomic Platform, Unité de Recherche en Génomique Végétale (URGV), INRA, Université d'Evry Val d'Essonne, CNRS, 91057 Evry, France
| | - Véronique Brunaud
- Bioinformatics for Predictive Genomics, URGV, INRA, Université d'Evry Val d'Essonne, CNRS, 91057 Evry, France
| | - Toshiyuki Ohnishi
- Graduate School of Agriculture, Shizuoka University, Shizuoka, 422-8529 Japan
| | - Ales Pencik
- Laboratory of Growth Regulators & Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University & Institute of Experimental Botany AS CR, 771 47 Olomouc, Czech Republic
| | - Patrick Achard
- Institute of Plant Molecular Biology, Centre National de la Recherche Scientifique (CNRS), University of Strasbourg, 67084 Strasbourg, France
| | - Fan Gong
- Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
| | - Peter Hedden
- Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
| | - Danièle Werck-Reichhart
- Institute of Plant Molecular Biology, Centre National de la Recherche Scientifique (CNRS), University of Strasbourg, 67084 Strasbourg, France; University of Strasbourg Institute for Advanced Study (USIAS), 67084 Strasbourg, France; Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, 79104 Freiburg, Germany.
| | - Hugues Renault
- Institute of Plant Molecular Biology, Centre National de la Recherche Scientifique (CNRS), University of Strasbourg, 67084 Strasbourg, France; University of Strasbourg Institute for Advanced Study (USIAS), 67084 Strasbourg, France; Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, 79104 Freiburg, Germany
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14
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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 Biol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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15
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Regnault T, Davière JM, Wild M, Sakvarelidze-Achard L, Heintz D, Carrera Bergua E, Lopez Diaz I, Gong F, Hedden P, Achard P. The gibberellin precursor GA12 acts as a long-distance growth signal in Arabidopsis. Nat Plants 2015; 1:15073. [PMID: 27250008 DOI: 10.1038/nplants.2015.73] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 04/22/2015] [Indexed: 05/07/2023]
Abstract
The gibberellin (GA) phytohormones play important roles in plant growth and development, promoting seed germination, elongation growth and reproductive development(1). Over the years, substantial progress has been made in understanding the regulation of GA signalling and metabolism, which ensures appropriate levels of GAs for growth and development(2). Moreover, an additional level of regulation may reside in the transport of GAs from production sites to recipient tissues that require GAs for growth. Although there is considerable evidence suggesting the existence of short- and long-distance movement of GAs in plants(3-8), the nature and the biological properties of this transport are not yet understood. Here, we combine biochemical and conventional micrografting experiments in Arabidopsis thaliana to show that the GA precursor GA12, although biologically inactive by itself, is the major mobile GA signal over long distances. Quantitative analysis of endogenous GAs in xylem and phloem exudates further indicates that GA12 moves through the plant vascular system. Finally, we demonstrate that GA12 is functional in recipient tissues, supporting growth via the activation of the GA signalling cascade. Collectively, these results reveal the existence of long-range transport of endogenous GA12 in plants that may have implications for the control of developmental phase transitions and the adaptation to adverse environments.
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Affiliation(s)
- Thomas Regnault
- Institut de Biologie Moléculaire des Plantes, UPR2357, associé avec l'Université de Strasbourg, Strasbourg 67084, France
| | - Jean-Michel Davière
- Institut de Biologie Moléculaire des Plantes, UPR2357, associé avec l'Université de Strasbourg, Strasbourg 67084, France
| | - Michael Wild
- Institut de Biologie Moléculaire des Plantes, UPR2357, associé avec l'Université de Strasbourg, Strasbourg 67084, France
| | - Lali Sakvarelidze-Achard
- Institut de Biologie Moléculaire des Plantes, UPR2357, associé avec l'Université de Strasbourg, Strasbourg 67084, France
| | - Dimitri Heintz
- Institut de Biologie Moléculaire des Plantes, UPR2357, associé avec l'Université de Strasbourg, Strasbourg 67084, France
| | - Esther Carrera Bergua
- Instituto de Biología Molecular y Celular de Plantas, CSIC-UPV, Valencia 46022, Spain
| | - Isabel Lopez Diaz
- Instituto de Biología Molecular y Celular de Plantas, CSIC-UPV, Valencia 46022, Spain
| | - Fan Gong
- Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
| | - Peter Hedden
- Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
| | - Patrick Achard
- Institut de Biologie Moléculaire des Plantes, UPR2357, associé avec l'Université de Strasbourg, Strasbourg 67084, France
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16
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Kondhare K, Farrell A, Kettlewell P, Hedden P, Monaghan J. Pre-maturity α-amylase in wheat: The role of abscisic acid and gibberellins. J Cereal Sci 2015. [DOI: 10.1016/j.jcs.2015.03.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Abstract
Gibberellin research has its origins in Japan in the 19th century, when a disease of rice was shown to be due to a fungal infection. The symptoms of the disease including overgrowth of the seedling and sterility were later shown to be due to secretions of the fungus Gibberella fujikuroi (now reclassified as Fusarium fujikuroi), from which the name gibberellin was derived for the active component. The profound effect of gibberellins on plant growth and development, particularly growth recovery in dwarf mutants and induction of bolting and flowering in some rosette species, prompted speculation that these fungal metabolites were endogenous plant growth regulators and this was confirmed by chemical characterisation in the late 1950s. Gibberellins are now known to be present in vascular plants, and some fungal and bacterial species. The biosynthesis of gibberellins in plants and the fungus has been largely resolved in terms of the pathways, enzymes, genes and their regulation. The proposal that gibberellins act in plants by removing growth limitation was confirmed by the demonstration that they induce the degradation of the growth-inhibiting DELLA proteins. The mechanism by which this is achieved was clarified by the identification of the gibberellin receptor from rice in 2005. Current research on gibberellin action is focussed particularly on the function of DELLA proteins as regulators of gene expression. This review traces the history of gibberellin research with emphasis on the early discoveries that enabled the more recent advances in this field.
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Affiliation(s)
- Peter Hedden
- />Rothamsted Research, West Common, Harpenden, AL5 2JQ Hertfordshire UK
| | - Valerie Sponsel
- />Department of Biology, The University of Texas at San Antonio, San Antonio, TX 78249 USA
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18
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Abstract
Plant hormones are small molecules that regulate plant growth and development, as well as responses to changing environmental conditions. By modifying the production, distribution or signal transduction of these hormones, plants are able to regulate and coordinate both growth and/or stress tolerance to promote survival or escape from environmental stress. A central role for the gibberellin (GA) class of growth hormones in the response to abiotic stress is becoming increasingly evident. Reduction of GA levels and signalling has been shown to contribute to plant growth restriction on exposure to several stresses, including cold, salt and osmotic stress. Conversely, increased GA biosynthesis and signalling promote growth in plant escape responses to shading and submergence. In several cases, GA signalling has also been linked to stress tolerance. The transcriptional regulation of GA metabolism appears to be a major point of regulation of the GA pathway, while emerging evidence for interaction of the GA-signalling molecule DELLA with components of the signalling pathway for the stress hormone jasmonic acid suggests additional mechanisms by which GA signalling may integrate multiple hormone signalling pathways in the response to stress. Here, we review the evidence for the role of GA in these processes, and the regulation of the GA signalling pathway on exposure to abiotic stress. The potential mechanisms by which GA signalling modulates stress tolerance are also discussed.
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Kondhare K, Hedden P, Kettlewell P, Farrell A, Monaghan J. Use of the hormone-biosynthesis inhibitors fluridone and paclobutrazol to determine the effects of altered abscisic acid and gibberellin levels on pre-maturity α-amylase formation in wheat grains. J Cereal Sci 2014. [DOI: 10.1016/j.jcs.2014.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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20
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Kondhare KR, Hedden P, Kettlewell PS, Farrell AD, Monaghan JM. Quantifying the impact of exogenous abscisic acid and gibberellins on pre-maturity α-amylase formation in developing wheat grains. Sci Rep 2014; 4:5355. [PMID: 24942128 DOI: 10.1007/s10681-012-0706-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 05/21/2014] [Indexed: 05/27/2023] Open
Abstract
To study the role of abscisic acid (ABA) and gibberellins (GA) in pre-maturity α-amylase (PMA) formation in developing wheat grain, two glasshouse experiments were conducted under controlled conditions in the highly PMA-susceptible genotype Rialto. The first, determined the relative efficacy of applying hormone solutions by injection into the peduncle compared to direct application to the intact grain. The second, examined the effects of each hormone, applied by either method, at mid-grain development on PMA in mature grains. In the first experiment, tritiated ABA ((3)H-ABA) and gibberellic acid ((3)H-GA3) were diluted with unlabelled ABA (100 µM) and GA3 (50 µM), respectively, and applied at mid-grain development using both methods. Spikes were harvested after 24, 48 and 72 h from application, and hormone taken up by grains was determined. After 72 h, the uptake per grain in terms of hormones applied was approximately 13% for ABA and 8% for GA3 when applied onto the grains, and approximately 17% for ABA and 5% for GA3 when applied by injection. In the second experiment, applied ABA reduced, whereas applied GA3 increased α-amylase activity. This confirmed that exogenously applied ABA and GA were absorbed in sufficient amounts to alter grain metabolism and impact on PMA.
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Affiliation(s)
- Kirtikumar R Kondhare
- Harper Adams University, Department of Crop & Environment Sciences, Newport, TF10 8NB, UK
| | - Peter Hedden
- Rothamsted Research, Department of Plant Biology & Crop Science, Harpenden, AL5 2JQ, UK
| | - Peter S Kettlewell
- Harper Adams University, Department of Crop & Environment Sciences, Newport, TF10 8NB, UK
| | - Aidan D Farrell
- The University of the West Indies, Department of Life Sciences, St. Augustine, Trinidad, West Indies
| | - James M Monaghan
- Harper Adams University, Department of Crop & Environment Sciences, Newport, TF10 8NB, UK
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21
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Plackett ARG, Ferguson AC, Powers SJ, Wanchoo-Kohli A, Phillips AL, Wilson ZA, Hedden P, Thomas SG. DELLA activity is required for successful pollen development in the Columbia ecotype of Arabidopsis. New Phytol 2014; 201:825-836. [PMID: 24400898 PMCID: PMC4291109 DOI: 10.1111/nph.12571] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 09/15/2013] [Indexed: 05/18/2023]
Abstract
Excessive gibberellin (GA) signalling, mediated through the DELLA proteins, has a negative impact on plant fertility. Loss of DELLA activity in the monocot rice (Oryza sativa) causes complete male sterility, but not in the dicot model Arabidopsis (Arabidopsis thaliana) ecotype Landsberg erecta (Ler), in which DELLA function has been studied most extensively, leading to the assumption that DELLA activity is not essential for Arabidopsis pollen development. A novel DELLA fertility phenotype was identified in the Columbia (Col-0) ecotype that necessitates re-evaluation of the general conclusions drawn from Ler. Fertility phenotypes were compared between the Col-0 and Ler ecotypes under conditions of chemical and genetic GA overdose, including mutants in both ecotypes lacking the DELLA paralogues REPRESSOR OF ga1-3 (RGA) and GA INSENSITIVE (GAI). Ler displays a less severe fertility phenotype than Col-0 under GA treatment. Col-0 rga gai mutants, in contrast with the equivalent Ler phenotype, were entirely male sterile, caused by post-meiotic defects in pollen development, which were rescued by the reintroduction of DELLA into either the tapetum or developing pollen. We conclude that DELLA activity is essential for Arabidopsis pollen development. Differences between the fertility responses of Col-0 and Ler might be caused by differences in downstream signalling pathways or altered DELLA expression.
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Affiliation(s)
- Andrew R G Plackett
- Plant Biology and Crop Science Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Alison C Ferguson
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire, LE12 5RD, UK
| | - Stephen J Powers
- Biomathematics and Bioinformatics Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Aakriti Wanchoo-Kohli
- Plant Biology and Crop Science Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Andrew L Phillips
- Plant Biology and Crop Science Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Zoe A Wilson
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire, LE12 5RD, UK
| | - Peter Hedden
- Plant Biology and Crop Science Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Stephen G Thomas
- Plant Biology and Crop Science Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
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22
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Méndez C, Baginsky C, Hedden P, Gong F, Carú M, Rojas MC. Gibberellin oxidase activities in Bradyrhizobium japonicum bacteroids. Phytochemistry 2014; 98:101-9. [PMID: 24378220 DOI: 10.1016/j.phytochem.2013.11.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 10/29/2013] [Accepted: 11/21/2013] [Indexed: 05/28/2023]
Abstract
Bradyrhizobium japonicum bacteroids isolated from root nodules of soybean (Glycine max.) plants converted the gibberellin (GA) precursor [(14)C1]GA12 into several products identified by combined gas chromatography-mass spectrometry as [(14)C1]GA24, [(14)C1]GA9, [(14)C1]GA15, GA9 17-nor-16-one and unidentified products. The oxidation of GA12, catalyzed by the GA 20-oxidase, was present in symbiotic bacteroids from plants around flowering, but not in bacteroids from plants at either an early vegetative stage or at late growth stages. Expression of cps and ks genes, involved in ent-kaurene biosynthesis, was also demonstrated in bacteroids from soybean plants around flowering. Earlier precursors of the GA pathway, ent-[(14)C1]kaurenoic acid or [(14)C4]GA12-aldehyde, were efficiently utilized by B. japonicum bacteroids to give labelled GA9 plus intermediates partially oxidized at C-20, as well as GA9 17-nor-16-one and an unidentified product. No 3β or 13-hydroxylated [(14)C]GAs were detected in any of the incubations. Moreover the C19-GAs [(14)C1]GA4 or [(14)C1]GA20 were recovered unconverted upon incubation with the bacteroids which supports the absence of GA 3β-hydroxylase activity in B. japonicum. The bacterial 20-oxidase utilized the 13-hydroxylated substrates [(14)C1]GA53, [(14)C1]GA44 or [(14)C1]GA19, although with less efficiency than [(14)C1]GA12 to give [(14)C1]GA20 as final product, while the 3β-hydroxylated substrate [(14)C1]GA14 was converted to [(14)C1]GA4 to a very small extent. Endogenous GA9 and GA24 were identified by GC-MS in methanolic nodule extracts. These results suggest that B. japonicum bacteroids would synthesize GA9 under the symbiotic conditions present in soybean root nodules.
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Affiliation(s)
- Constanza Méndez
- Laboratorio de Bioorgánica, Departamento de Química, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile.
| | - Cecilia Baginsky
- Departamento de Producción Agrícola, Facultad de Ciencias Agronómicas, Universidad de Chile, Casilla 1004, Santiago, Chile.
| | - Peter Hedden
- Rothamsted Research, Harpenden, Herts AL5 2JQ, United Kingdom.
| | - Fan Gong
- Rothamsted Research, Harpenden, Herts AL5 2JQ, United Kingdom.
| | - Margarita Carú
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile.
| | - María Cecilia Rojas
- Laboratorio de Bioorgánica, Departamento de Química, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile.
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23
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Kondhare K, Kettlewell P, Farrell A, Hedden P, Monaghan J. The role of sensitivity to abscisic acid and gibberellin in pre-maturity α-amylase formation in wheat grains. J Cereal Sci 2013. [DOI: 10.1016/j.jcs.2013.09.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Teillet A, Dybal K, Kerry BR, Miller AJ, Curtis RHC, Hedden P. Transcriptional changes of the root-knot nematode Meloidogyne incognita in response to Arabidopsis thaliana root signals. PLoS One 2013; 8:e61259. [PMID: 23593446 PMCID: PMC3625231 DOI: 10.1371/journal.pone.0061259] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 03/11/2013] [Indexed: 12/02/2022] Open
Abstract
Root-knot nematodes are obligate parasites that invade roots and induce the formation of specialized feeding structures. Although physiological and molecular changes inside the root leading to feeding site formation have been studied, very little is known about the molecular events preceding root penetration by nematodes. In order to investigate the influence of root exudates on nematode gene expression before plant invasion and to identify new genes potentially involved in parasitism, sterile root exudates from the model plant Arabidopsis thaliana were produced and used to treat Meloidogyne incognita pre-parasitic second-stage juveniles. After confirming the activity of A. thaliana root exudates (ARE) on M. incognita stylet thrusting, six new candidate genes identified by cDNA-AFLP were confirmed by qRT-PCR as being differentially expressed after incubation for one hour with ARE. Using an in vitro inoculation method that focuses on the events preceding the root penetration, we show that five of these genes are differentially expressed within hours of nematode exposure to A. thaliana roots. We also show that these genes are up-regulated post nematode penetration during migration and feeding site initiation. This study demonstrates that preceding root invasion plant-parasitic nematodes are able to perceive root signals and to respond by changing their behaviour and gene expression.
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Affiliation(s)
- Alice Teillet
- Rothamsted Research, Harpenden, Herts, United Kingdom.
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25
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Urbanová T, Tarkowská D, Novák O, Hedden P, Strnad M. Analysis of gibberellins as free acids by ultra performance liquid chromatography-tandem mass spectrometry. Talanta 2013; 112:85-94. [PMID: 23708542 DOI: 10.1016/j.talanta.2013.03.068] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 03/18/2013] [Accepted: 03/25/2013] [Indexed: 11/17/2022]
Abstract
A robust, reliable and high-throughput method for extraction and purification of gibberellins (GAs), a group of tetracyclic diterpenoid carboxylic acids that include endogenous growth hormones, from plant material was developed. The procedure consists of two solid-phase extraction steps (Oasis(®) MCX-HLB and Oasis(®) MAX) and gives selective enrichment and efficient clean-up of these compounds from complex plant extracts. The method was tested with plant extracts of Brassica napus and Arabidopsis thaliana, from which total recovery of internal standards of about 72% was achieved. A rapid baseline chromatographic separation of 20 non-derivatised GAs by ultra performance liquid chromatography is also presented where a reversed-phase chromatographic column Acquity CSH(®) and a mobile phase consisting of methanol and aqueous 10mM-ammonium formate is used. This method enables sensitive and precise quantitation of GAs by MS/MS in multiple-reaction monitoring mode (MRM) by a standard isotope dilution method. Optimal conditions, including final flow rate, desolvation temperature, desolvation gas flow, capillary and cone voltage for effective ionisation in the electrospray ion source were found. All studied GAs were determined as free acids giving dominant quasi-molecular ions of [M-H](-) with limits of detection ranging between 0.08 and 10 fmol and linear ranges over four orders of magnitude. Taking advantage of highly effective chromatographic separation of 20 GAs and very sensitive mass spectrometric detection, the presented bioanalytical method serves as a useful tool for plant biologists studying the physiological roles of these hormones in plant development.
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Affiliation(s)
- Terezie Urbanová
- Laboratory of Growth Regulators, Faculty of Sciences, Palacký University & Institute of Experimental Botany Academy of Sciences of the Czech Republic, v.v.i., Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic.
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26
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García-Hurtado N, Carrera E, Ruiz-Rivero O, López-Gresa MP, Hedden P, Gong F, García-Martínez JL. The characterization of transgenic tomato overexpressing gibberellin 20-oxidase reveals induction of parthenocarpic fruit growth, higher yield, and alteration of the gibberellin biosynthetic pathway. J Exp Bot 2012; 63:5803-13. [PMID: 22945942 DOI: 10.1093/jxb/ers229] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Fruit-set and growth in tomato depend on the action of gibberellins (GAs). To evaluate the role of the GA biosynthetic enzyme GA 20-oxidase (GA20ox) in that process, the citrus gene CcGA20ox1 was overexpressed in tomato (Solanum lycopersicum L.) cv Micro-Tom. The transformed plants were taller, had non-serrated leaves, and some flowers displayed a protruding stigma due to a longer style, thus preventing self-pollination, similar to GA(3)-treated plants. Flowering was delayed compared with wild-type (WT) plants. Both yield and number of fruits per plant, some of them seedless, were higher in the transgenic plants. The Brix index value of fruit juice was also higher due to elevated citric acid content, but not glucose or fructose content. When emasculated, 14-30% of ovaries from transgenic flowers developed parthenocarpically, whereas no parthenocarpy was found in emasculated WT flowers. The presence of early-13-hydroxylation and non-13-hydroxylation GA pathways was demonstrated in the shoot and fruit of Micro-Tom, as well as in two tall tomato cultivars (Ailsa Craig and UC-82). The transgenic plants had altered GA profiles containing higher concentrations of GA(4), from the non-13-hydroxylation pathway, which is generally a minor active GA in tomato. The effect of GA(4) application in enhancing stem growth and parthenocarpic fruit development was proportional to dose, with the same activity as GA(1). The results support the contention that GA20ox overexpression diverts GA metabolism from the early-13-hydroxylation pathway to the non-13-hydroxylation pathway. This led to enhanced GA(4) synthesis and higher yield, although the increase in GA(4) content in the ovary was not sufficient to induce full parthenocarpy.
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Affiliation(s)
- Noemí García-Hurtado
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Ingeniero Fausto Elío s/n, 46022 Valencia, Spain
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27
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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 Physiol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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28
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Gasperini D, Greenland A, Hedden P, Dreos R, Harwood W, Griffiths S. Genetic and physiological analysis of Rht8 in bread wheat: an alternative source of semi-dwarfism with a reduced sensitivity to brassinosteroids. J Exp Bot 2012; 63:4419-36. [PMID: 22791821 PMCID: PMC3421992 DOI: 10.1093/jxb/ers138] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 03/07/2012] [Accepted: 03/26/2012] [Indexed: 05/18/2023]
Abstract
Over the next decade, wheat grain production must increase to meet the demand of a fast growing human population. One strategy to meet this challenge is to raise wheat productivity by optimizing plant stature. The Reduced height 8 (Rht8) semi-dwarfing gene is one of the few, together with the Green Revolution genes, to reduce stature of wheat (Triticum aestivum L.), and improve lodging resistance, without compromising grain yield. Rht8 is widely used in dry environments such as Mediterranean countries where it increases plant adaptability. With recent climate change, its use could become increasingly important even in more northern latitudes. In the present study, the characterization of Rht8 was furthered. Morphological analyses show that the semi-dwarf phenotype of Rht8 lines is due to shorter internodal segments along the wheat culm, achieved through reduced cell elongation. Physiological experiments show that the reduced cell elongation is not due to defective gibberellin biosynthesis or signalling, but possibly to a reduced sensitivity to brassinosteroids. Using a fine-resolution mapping approach and screening 3104 F(2) individuals of a newly developed mapping population, the Rht8 genetic interval was reduced from 20.5 cM to 1.29 cM. Comparative genomics with model genomes confined the Rht8 syntenic intervals to 3.3 Mb of the short arm of rice chromosome 4, and to 2 Mb of Brachypodium distachyon chromosome 5. The very high resolution potential of the plant material generated is crucial for the eventual cloning of Rht8.
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Affiliation(s)
- Debora Gasperini
- Crop Genetics Department, John Innes Centre, Norwich Research Park, Colney, NorwichNR4 7UHUK
| | - Andy Greenland
- National Institute of Agricultural Botany, Huntingdon Road, CambridgeCB3 0LEUK
| | - Peter Hedden
- Rothamsted Research, Harpenden, HertfordshireAL5 2JQUK
| | - René Dreos
- École Polytechnique Fédérale de Lausanne, School of Life Sciences, CH-1015 Lausanne, Switzerland
| | - Wendy Harwood
- Crop Genetics Department, John Innes Centre, Norwich Research Park, Colney, NorwichNR4 7UHUK
| | - Simon Griffiths
- Crop Genetics Department, John Innes Centre, Norwich Research Park, Colney, NorwichNR4 7UHUK
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29
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Studt L, Troncoso C, Gong F, Hedden P, Toomajian C, Leslie JF, Humpf HU, Rojas MC, Tudzynski B. Segregation of secondary metabolite biosynthesis in hybrids of Fusarium fujikuroi and Fusarium proliferatum. Fungal Genet Biol 2012; 49:567-77. [PMID: 22626844 DOI: 10.1016/j.fgb.2012.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 05/08/2012] [Accepted: 05/13/2012] [Indexed: 10/28/2022]
Abstract
Fusarium fujikuroi and Fusarium proliferatum are two phylogenetically closely related species of the Gibberella fujikuroi species complex (GFC). In some cases, strains of these species can cross and produce a few ascospores. In this study, we analyzed 26 single ascospore isolates of an interspecific cross between F. fujikuroi C1995 and F. proliferatum D4854 for their ability to produce four secondary metabolites: gibberellins (GAs), the mycotoxins fusarin C and fumonisin B(1), and a family of red polyketides, the fusarubins. Both parental strains contain the biosynthetic genes for all four metabolites, but differ in their ability to produce these metabolites under certain conditions. F. fujikuroi C1995 produces GAs and fusarins, while F. proliferatum D4854 produces fumonisins and fusarubins. The segregation amongst the progeny of these traits is not the expected 1:1 Mendelian ratio. Only eight, six, three and three progeny, respectively, produce GAs, fusarins, fumonisin B(1) and fusarubins in amounts similar to those synthesized by the producing parental strain. Beside the eight highly GA(3)-producing progeny, some of the progeny produce small amounts of GAs, predominantly GA(1), although these strains contain the GA gene cluster of the non-GA-producing F. proliferatum parental strain. Some progeny had recombinant secondary metabolite profiles under the conditions examined indicating that interspecific crosses can yield secondary metabolite production profiles that are atypical of the parent species.
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Affiliation(s)
- L Studt
- Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, Hindenburgplatz 55, 48143 Münster, Germany
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30
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Middleton AM, Úbeda-Tomás S, Griffiths J, Holman T, Hedden P, Thomas SG, Phillips AL, Holdsworth MJ, Bennett MJ, King JR, Owen MR. Mathematical modeling elucidates the role of transcriptional feedback in gibberellin signaling. Proc Natl Acad Sci U S A 2012; 109:7571-6. [PMID: 22523240 PMCID: PMC3358864 DOI: 10.1073/pnas.1113666109] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The hormone gibberellin (GA) is a key regulator of plant growth. Many of the components of the gibberellin signal transduction [e.g., GIBBERELLIN INSENSITIVE DWARF 1 (GID1) and DELLA], biosynthesis [e.g., GA 20-oxidase (GA20ox) and GA3ox], and deactivation pathways have been identified. Gibberellin binds its receptor, GID1, to form a complex that mediates the degradation of DELLA proteins. In this way, gibberellin relieves DELLA-dependent growth repression. However, gibberellin regulates expression of GID1, GA20ox, and GA3ox, and there is also evidence that it regulates DELLA expression. In this paper, we use integrated mathematical modeling and experiments to understand how these feedback loops interact to control gibberellin signaling. Model simulations are in good agreement with in vitro data on the signal transduction and biosynthesis pathways and in vivo data on the expression levels of gibberellin-responsive genes. We find that GA-GID1 interactions are characterized by two timescales (because of a lid on GID1 that can open and close slowly relative to GA-GID1 binding and dissociation). Furthermore, the model accurately predicts the response to exogenous gibberellin after a number of chemical and genetic perturbations. Finally, we investigate the role of the various feedback loops in gibberellin signaling. We find that regulation of GA20ox transcription plays a significant role in both modulating the level of endogenous gibberellin and generating overshoots after the removal of exogenous gibberellin. Moreover, although the contribution of other individual feedback loops seems relatively small, GID1 and DELLA transcriptional regulation acts synergistically with GA20ox feedback.
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Affiliation(s)
- Alistair M. Middleton
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, United Kingdom
- Zentrum für Biosystemanalyse, Albert-Ludwigs-Universität, 79104 Freiburg im Breisgau, Germany
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom; and
| | - Susana Úbeda-Tomás
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, United Kingdom
| | - Jayne Griffiths
- Plant Science Department, Rothamsted Research, Harpenden, Herts AL5 2JQ, United Kingdom
| | - Tara Holman
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, United Kingdom
| | - Peter Hedden
- Plant Science Department, Rothamsted Research, Harpenden, Herts AL5 2JQ, United Kingdom
| | - Stephen G. Thomas
- Plant Science Department, Rothamsted Research, Harpenden, Herts AL5 2JQ, United Kingdom
| | - Andrew L. Phillips
- Plant Science Department, Rothamsted Research, Harpenden, Herts AL5 2JQ, United Kingdom
| | - Michael J. Holdsworth
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, United Kingdom
| | - Malcolm J. Bennett
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, United Kingdom
| | - John R. King
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, United Kingdom
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom; and
| | - Markus R. Owen
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, United Kingdom
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom; and
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Bhattacharya A, Ward DA, Hedden P, Phillips AL, Power JB, Davey MR. Engineering gibberellin metabolism in Solanum nigrum L. by ectopic expression of gibberellin oxidase genes. Plant Cell Rep 2012; 31:945-953. [PMID: 22238061 DOI: 10.1007/s00299-011-1214-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 12/05/2011] [Accepted: 12/12/2011] [Indexed: 05/31/2023]
Abstract
Gibberellins (GAs) control many aspects of plant development, including seed germination, shoot growth, flower induction and growth and fruit expansion. Leaf explants of Solanum nigrum (Black Nightshade; Solanaceae) were used for Agrobacterium-mediated delivery of GA-biosynthetic genes to determine the influence of their encoded enzymes on the production of bioactive GAs and plant stature in this species. Constructs were prepared containing the neomycin phosphotransferase (nptII) gene for kanamycin resistance as a selectable marker, and the GA-biosynthetic genes, their expression under the control of the CaMV 35S promoter. The GA-biosynthetic genes comprised AtGA20ox1, isolated from Arabidopsis thaliana, the product from which catalyses the formation of C(19)-GAs, and MmGA3ox1 and MmGA3ox2, isolated from Marah macrocarpus, which encode functionally different GA 3-oxidases that convert C(19)-GAs to biologically active forms. Increase in stature was observed in plants transformed with AtGA20ox1, MmGA3ox2 and MmGA3ox1 + MmGA3ox2, their presence and expression being confirmed by PCR and RT-PCR, respectively, accompanied by an increase in GA(1) content. Interestingly, MmGA3ox1 alone did not induce a sustained increase in plant height, probably because of only a marginal increase in bioactive GA(1) content in the transformed plants. The results are discussed in the context of regulating plant stature, since this strategy would decrease the use of chemicals to promote plant growth.
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Affiliation(s)
- A Bhattacharya
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
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Mutasa-Göttgens ES, Joshi A, Holmes HF, Hedden P, Göttgens B. A new RNASeq-based reference transcriptome for sugar beet and its application in transcriptome-scale analysis of vernalization and gibberellin responses. BMC Genomics 2012. [PMID: 22429863 DOI: 10.1186/1471‐2164‐13‐99] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Sugar beet (Beta vulgaris sp. vulgaris) crops account for about 30% of world sugar. Sugar yield is compromised by reproductive growth hence crops must remain vegetative until harvest. Prolonged exposure to cold temperature (vernalization) in the range 6 °C to 12 °C induces reproductive growth, leading to bolting (rapid elongation of the main stem) and flowering. Spring cultivation of crops in cool temperate climates makes them vulnerable to vernalization and hence bolting, which is initiated in the apical shoot meristem in processes involving interaction between gibberellin (GA) hormones and vernalization. The underlying mechanisms are unknown and genome scale next generation sequencing approaches now offer comprehensive strategies to investigate them; enabling the identification of novel targets for bolting control in sugar beet crops. In this study, we demonstrate the application of an mRNA-Seq based strategy for this purpose. RESULTS There is no sugar beet reference genome, or public expression array platforms. We therefore used RNA-Seq to generate the first reference transcriptome. We next performed digital gene expression profiling using shoot apex mRNA from two sugar beet cultivars with and without applied GA, and also a vernalized cultivar with and without applied GA. Subsequent bioinformatics analyses identified transcriptional changes associated with genotypic difference and experimental treatments. Analysis of expression profiles in response to vernalization and GA treatment suggested previously unsuspected roles for a RAV1-like AP2/B3 domain protein in vernalization and efflux transporters in the GA response. CONCLUSIONS Next generation RNA-Seq enabled the generation of the first reference transcriptome for sugar beet and the study of global transcriptional responses in the shoot apex to vernalization and GA treatment, without the need for a reference genome or established array platforms. Comprehensive bioinformatic analysis identified transcriptional programmes associated with different sugar beet genotypes as well as biological treatments; thus providing important new opportunities for basic scientists and sugar beet breeders. Transcriptome-scale identification of agronomically important traits as used in this study should be widely applicable to all crop plants where genomic resources are limiting.
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Affiliation(s)
- Effie S Mutasa-Göttgens
- Rothamsted Research-Broom's Barn, Department of Applied Crop Science, Higham, Bury St Edmunds, Suffolk IP26 6NP, UK.
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Mutasa-Göttgens ES, Joshi A, Holmes HF, Hedden P, Göttgens B. A new RNASeq-based reference transcriptome for sugar beet and its application in transcriptome-scale analysis of vernalization and gibberellin responses. BMC Genomics 2012; 13:99. [PMID: 22429863 PMCID: PMC3340327 DOI: 10.1186/1471-2164-13-99] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2011] [Accepted: 03/19/2012] [Indexed: 12/15/2022] Open
Abstract
Background Sugar beet (Beta vulgaris sp. vulgaris) crops account for about 30% of world sugar. Sugar yield is compromised by reproductive growth hence crops must remain vegetative until harvest. Prolonged exposure to cold temperature (vernalization) in the range 6°C to 12°C induces reproductive growth, leading to bolting (rapid elongation of the main stem) and flowering. Spring cultivation of crops in cool temperate climates makes them vulnerable to vernalization and hence bolting, which is initiated in the apical shoot meristem in processes involving interaction between gibberellin (GA) hormones and vernalization. The underlying mechanisms are unknown and genome scale next generation sequencing approaches now offer comprehensive strategies to investigate them; enabling the identification of novel targets for bolting control in sugar beet crops. In this study, we demonstrate the application of an mRNA-Seq based strategy for this purpose. Results There is no sugar beet reference genome, or public expression array platforms. We therefore used RNA-Seq to generate the first reference transcriptome. We next performed digital gene expression profiling using shoot apex mRNA from two sugar beet cultivars with and without applied GA, and also a vernalized cultivar with and without applied GA. Subsequent bioinformatics analyses identified transcriptional changes associated with genotypic difference and experimental treatments. Analysis of expression profiles in response to vernalization and GA treatment suggested previously unsuspected roles for a RAV1-like AP2/B3 domain protein in vernalization and efflux transporters in the GA response. Conclusions Next generation RNA-Seq enabled the generation of the first reference transcriptome for sugar beet and the study of global transcriptional responses in the shoot apex to vernalization and GA treatment, without the need for a reference genome or established array platforms. Comprehensive bioinformatic analysis identified transcriptional programmes associated with different sugar beet genotypes as well as biological treatments; thus providing important new opportunities for basic scientists and sugar beet breeders. Transcriptome-scale identification of agronomically important traits as used in this study should be widely applicable to all crop plants where genomic resources are limiting.
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Affiliation(s)
- Effie S Mutasa-Göttgens
- Rothamsted Research-Broom's Barn, Department of Applied Crop Science, Higham, Bury St Edmunds, Suffolk IP26 6NP, UK.
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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. 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Urbanová T, Tarkowská D, Strnad M, Hedden P. Gibberellins – terpenoid plant hormones: Biological importance and chemical analysis. ACTA ACUST UNITED AC 2012. [DOI: 10.1135/cccc2011098] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Gibberellins (GAs) are a large group of diterpenoid carboxylic acids, some members of which function as plant hormones controlling diverse aspects of growth and development. Biochemical, genetic, and genomic approaches have led to the identification of the majority of the genes that encode GA biosynthesis and deactivation enzymes. Recent studies have shown that both GA biosynthesis and deactivation pathways are tightly regulated by developmental, hormonal, and environmental signals, consistent with the role of GAs as key growth regulators. In this review, we summarize our current understanding of the GA biosynthesis and deactivation pathways in plants and fungi, and discuss methods for their qualitative and quantitative analysis. The challenges for their extraction and purification from plant tissues, which form complex matrices containing thousands of interfering substances, are discussed.
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Dayan J, Voronin N, Gong F, Sun TP, Hedden P, Fromm H, Aloni R. Leaf-induced gibberellin signaling is essential for internode elongation, cambial activity, and fiber differentiation in tobacco stems. Plant Cell 2012; 24:66-79. [PMID: 22253226 PMCID: PMC3289570 DOI: 10.1105/tpc.111.093096] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 12/19/2011] [Accepted: 12/31/2011] [Indexed: 05/17/2023]
Abstract
The gibberellins (GAs) are a group of endogenous compounds that promote the growth of most plant organs, including stem internodes. We show that in tobacco (Nicotiana tabacum) the presence of leaves is essential for the accumulation of bioactive GAs and their immediate precursors in the stem and consequently for normal stem elongation, cambial proliferation, and xylem fiber differentiation. These processes do not occur in the absence of maturing leaves but can be restored by application of C(19)-GAs, identifying the presence of leaves as a requirement for GA signaling in stems and revealing the fundamental role of GAs in secondary growth regulation. The use of reporter genes for GA activity and GA-directed DELLA protein degradation in Arabidopsis thaliana confirms the presence of a mobile signal from leaves to the stem that induces GA signaling.
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Affiliation(s)
- Jonathan Dayan
- Department of Molecular Biology and Ecology of Plants, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
- Department of Biology, Duke University, Durham, North Carolina 27708
| | - Nickolay Voronin
- Department of Molecular Biology and Ecology of Plants, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Fan Gong
- Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
| | - Tai-ping Sun
- Department of Biology, Duke University, Durham, North Carolina 27708
| | - Peter Hedden
- Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
| | - Hillel Fromm
- Department of Molecular Biology and Ecology of Plants, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Roni Aloni
- Department of Molecular Biology and Ecology of Plants, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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Pearce S, Saville R, Vaughan SP, Chandler PM, Wilhelm EP, Sparks CA, Al-Kaff N, Korolev A, Boulton MI, Phillips AL, Hedden P, Nicholson P, Thomas SG. Molecular characterization of Rht-1 dwarfing genes in hexaploid wheat. Plant Physiol 2011; 157:1820-31. [PMID: 22013218 PMCID: PMC3327217 DOI: 10.1104/pp.111.183657] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Accepted: 10/19/2011] [Indexed: 05/18/2023]
Abstract
The introduction of the Reduced height (Rht)-B1b and Rht-D1b semidwarfing genes led to impressive increases in wheat (Triticum aestivum) yields during the Green Revolution. The reduction in stem elongation in varieties containing these alleles is caused by a limited response to the phytohormone gibberellin (GA), resulting in improved resistance to stem lodging and yield benefits through an increase in grain number. Rht-B1 and Rht-D1 encode DELLA proteins, which act to repress GA-responsive growth, and their mutant alleles Rht-B1b and Rht-D1b are thought to confer dwarfism by producing more active forms of these growth repressors. While no semidwarfing alleles of Rht-A1 have been identified, we show that this gene is expressed at comparable levels to the other homeologs and represents a potential target for producing novel dwarfing alleles. In this study, we have characterized additional dwarfing mutations in Rht-B1 and Rht-D1. We show that the severe dwarfism conferred by Rht-B1c is caused by an intragenic insertion, which results in an in-frame 90-bp insertion in the transcript and a predicted 30-amino acid insertion within the highly conserved amino-terminal DELLA domain. In contrast, the extreme dwarfism of Rht-D1c is due to overexpression of the semidwarfing Rht-D1b allele, caused by an increase in gene copy number. We show also that the semidwarfing alleles Rht-B1d and Rht-B1e introduce premature stop codons within the amino-terminal coding region. Yeast two-hybrid assays indicate that these newly characterized mutations in Rht-B1 and Rht-D1 confer "GA-insensitive" dwarfism by producing DELLA proteins that do not bind the GA receptor GA INSENSITIVE DWARF1, potentially compromising their targeted degradation.
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Plackett ARG, Thomas SG, Wilson ZA, Hedden P. Gibberellin control of stamen development: a fertile field. Trends Plant Sci 2011; 16:568-78. [PMID: 21824801 DOI: 10.1016/j.tplants.2011.06.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 06/24/2011] [Accepted: 06/30/2011] [Indexed: 05/04/2023]
Abstract
Stamen development is governed by a conserved genetic pathway, within which the role of hormones has been the subject of considerable recent research. Our understanding of the involvement of gibberellin (GA) signalling in this developmental process is further advanced than for the other phytohormones, and here we review recent experimental results in rice (Oryza sativa) and Arabidopsis (Arabidopsis thaliana) that have provided insight into the timing and mechanisms of GA regulation of stamen development, identifying the tapetum and developing pollen as major targets. GA signalling governs both tapetum secretory functions and entry into programmed cell death via the GAMYB class of transcription factor, the targets of which integrate with the established genetic framework for the regulation of tapetum function at multiple hierarchical levels.
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Kerchev PI, Pellny TK, Vivancos PD, Kiddle G, Hedden P, Driscoll S, Vanacker H, Verrier P, Hancock RD, Foyer CH. The transcription factor ABI4 Is required for the ascorbic acid-dependent regulation of growth and regulation of jasmonate-dependent defense signaling pathways in Arabidopsis. Plant Cell 2011; 23:3319-34. [PMID: 21926335 PMCID: PMC3203439 DOI: 10.1105/tpc.111.090100] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 08/03/2011] [Accepted: 08/30/2011] [Indexed: 05/18/2023]
Abstract
Cellular redox homeostasis is a hub for signal integration. Interactions between redox metabolism and the ABSCISIC ACID-INSENSITIVE-4 (ABI4) transcription factor were characterized in the Arabidopsis thaliana vitamin c defective1 (vtc1) and vtc2 mutants, which are defective in ascorbic acid synthesis and show a slow growth phenotype together with enhanced abscisic acid (ABA) levels relative to the wild type (Columbia-0). The 75% decrease in the leaf ascorbate pool in the vtc2 mutants was not sufficient to adversely affect GA metabolism. The transcriptome signatures of the abi4, vtc1, and vtc2 mutants showed significant overlap, with a large number of transcription factors or signaling components similarly repressed or induced. Moreover, lincomycin-dependent changes in LIGHT HARVESTING CHLOROPHYLL A/B BINDING PROTEIN 1.1 expression were comparable in these mutants, suggesting overlapping participation in chloroplast to nucleus signaling. The slow growth phenotype of vtc2 was absent in the abi4 vtc2 double mutant, as was the sugar-insensitive phenotype of the abi4 mutant. Octadecanoid derivative-responsive AP2/ERF-domain transcription factor 47 (ORA47) and AP3 (an ABI5 binding factor) transcripts were enhanced in vtc2 but repressed in abi4 vtc2, suggesting that ABI4 and ascorbate modulate growth and defense gene expression through jasmonate signaling. We conclude that low ascorbate triggers ABA- and jasmonate-dependent signaling pathways that together regulate growth through ABI4. Moreover, cellular redox homeostasis exerts a strong influence on sugar-dependent growth regulation.
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Affiliation(s)
- Pavel I. Kerchev
- Centre for Plant Sciences, Faculty of Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
- The James Hutton Institute, Invergowrie, Dundee DD2 5DA, United Kingdom
| | - Till K. Pellny
- Plant Science Department, Centre for Crop Genetic Improvement, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
| | - Pedro Diaz Vivancos
- Centre for Plant Sciences, Faculty of Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
- Department of Plant Breeding, Centro de Edafología y Biología Aplicada del Segura–Consejo Superior de Investigaciones Científicas, 30100-Murcia, Campus de Espinardo, Spain
| | - Guy Kiddle
- Plant Science Department, Centre for Crop Genetic Improvement, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
| | - Peter Hedden
- Plant Science Department, Centre for Crop Genetic Improvement, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
| | - Simon Driscoll
- Centre for Plant Sciences, Faculty of Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Hélène Vanacker
- Institut de Biologie des Plantes, Université de Paris sud 11, 91405 Orsay cedex, Paris, France
| | - Paul Verrier
- Department of Biomathematics, Bioinformatics Centre for Mathematical and Computational Biology, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
| | - Robert D. Hancock
- The James Hutton Institute, Invergowrie, Dundee DD2 5DA, United Kingdom
| | - Christine H. Foyer
- Centre for Plant Sciences, Faculty of Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
- Address correspondence to
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Ma (马谦) Q, Hedden P, Zhang (张启发) Q. Heterosis in rice seedlings: its relationship to gibberellin content and expression of gibberellin metabolism and signaling genes. Plant Physiol 2011; 156:1905-20. [PMID: 21693671 PMCID: PMC3149939 DOI: 10.1104/pp.111.178046] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 06/19/2011] [Indexed: 05/06/2023]
Abstract
Despite the accumulation of data on the genetic and molecular understanding of heterosis, there is little information on the regulation of heterosis at the physiological level. In this study, we performed a quantitative analysis of endogenous gibberellin (GA) content and expression profiling of the GA metabolism and signaling genes to investigate the possible relationship between GA signaling and heterosis for seedling development in rice (Oryza sativa). The materials used were an incomplete diallele set of 3 × 3 crosses and the six parents. In the growing shoots of the seedlings at 20 d after sowing, significant positive correlations between the contents of some GA species and performance and heterosis based on shoot dry mass were detected. Expression analyses of GA-related genes by real-time reverse transcription-polymerase chain reaction revealed that 13 out of the 16 GA-related genes examined exhibited significant differential expression among the F1 hybrid and its parents, acting predominantly in the modes of overdominance and positive dominance. Expression levels of nine genes in the hybrids displayed significant positive correlations with the heterosis of shoot dry mass. These results imply that GAs play a positive role in the regulation of heterosis for rice seedling development. In shoots plus root axes of 4-d-old germinating seeds that had undergone the deetiolation, mimicking normal germination in soil, the axis dry mass was positively correlated with the content of GA₂₉ but negatively correlated with that of GA₁₉. Our findings provide supporting evidence for GAs playing an important regulatory role in heterosis for rice seedling development.
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Affiliation(s)
| | | | - Qifa Zhang (张启发)
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China (Q.M., Q.Z.); Centre for Crop Genetic Improvement, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom (P.H.)
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Fernandez-Garcia N, Hernandez M, Casado-Vela J, Bru R, Elortza F, Hedden P, Olmos E. Changes to the proteome and targeted metabolites of xylem sap in Brassica oleracea in response to salt stress. Plant Cell Environ 2011; 34:821-36. [PMID: 21276013 DOI: 10.1111/j.1365-3040.2011.02285.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Root-to-shoot signalling via xylem sap is an important mechanism by which plants respond to stress. This signalling could be mediated by alteration in the concentrations of inorganic and/or organic molecules. The effect of salt stress on the contents of xylem sap in Brassica olarecea has been analysed by mass spectrometry in order to quantify these changes. Subcellular location of arabinogalactan proteins (AGPs) by immunogold labelling and peroxidase isozymes was also analysed by isoelectrofocusing. The xylem sap metabolome analysis demonstrated the presence of many organic compounds such as sugars, organic acids and amino acids. Of these, amino acid concentrations, particularly that of glutamine, the major amino acid in the sap, were substantially reduced by salt stress. The xylem sap proteome analysis demonstrated the accumulation of enzymes involved in xylem differentiation and lignification, such as cystein proteinases, acid peroxidases, and a putative hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyl transferase under salt stress. The peroxidase isozyme pattern showed that salt stress induced a high accumulation of an acid isoform. These results suggest that xylem differentiation and lignification is induced by salt stress. The combination of different methods to analyse the xylem sap composition provides new insights into mechanisms in plant development and signalling under salt stress.
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Affiliation(s)
- N Fernandez-Garcia
- Department of Abiotic Stress and Plant Pathology. CEBAS-CSIC. P.O. Box 164. Murcia, Spain
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Hartmann A, Senning M, Hedden P, Sonnewald U, Sonnewald S. Reactivation of meristem activity and sprout growth in potato tubers require both cytokinin and gibberellin. Plant Physiol 2011; 155:776-96. [PMID: 21163959 PMCID: PMC3032466 DOI: 10.1104/pp.110.168252] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Reactivation of dormant meristems is of central importance for plant fitness and survival. Due to their large meristem size, potato (Solanum tuberosum) tubers serve as a model system to study the underlying molecular processes. The phytohormones cytokinins (CK) and gibberellins (GA) play important roles in releasing potato tuber dormancy and promoting sprouting, but their mode of action in these processes is still obscure. Here, we established an in vitro assay using excised tuber buds to study the dormancy-releasing capacity of GA and CK and show that application of gibberellic acid (GA(3)) is sufficient to induce sprouting. In contrast, treatment with 6-benzylaminopurine induced bud break but did not support further sprout growth unless GA(3) was administered additionally. Transgenic potato plants expressing Arabidopsis (Arabidopsis thaliana) GA 20-oxidase or GA 2-oxidase to modify endogenous GA levels showed the expected phenotypical changes as well as slight effects on tuber sprouting. The isopentenyltransferase (IPT) from Agrobacterium tumefaciens and the Arabidopsis cytokinin oxidase/dehydrogenase1 (CKX) were exploited to modify the amounts of CK in transgenic potato plants. IPT expression promoted earlier sprouting in vitro. Strikingly, CKX-expressing tubers exhibited a prolonged dormancy period and did not respond to GA(3). This supports an essential role of CK in terminating tuber dormancy and indicates that GA is not sufficient to break dormancy in the absence of CK. GA(3)-treated wild-type and CKX-expressing tuber buds were subjected to a transcriptome analysis that revealed transcriptional changes in several functional groups, including cell wall metabolism, cell cycle, and auxin and ethylene signaling, denoting events associated with the reactivation of dormant meristems.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Mutasa-Göttgens ES, Qi A, Zhang W, Schulze-Buxloh G, Jennings A, Hohmann U, Müller AE, Hedden P. Bolting and flowering control in sugar beet: relationships and effects of gibberellin, the bolting gene B and vernalization. AoB Plants 2010; 2010:plq012. [PMID: 22476070 PMCID: PMC3000703 DOI: 10.1093/aobpla/plq012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Revised: 07/27/2010] [Accepted: 08/03/2010] [Indexed: 05/25/2023]
Abstract
BACKGROUND AND AIMS Bolting, the first visible sign of reproductive transition in beets (Beta vulgaris), is controlled by the dominant bolting gene B (B allele), which allows for flowering under long days (LDs, >14 h light) without prior vernalization. The B-locus carries recessive alleles (bb) in sugar beet (Beta vulgaris L. spp. vulgaris), so that vernalization and LDs are required for bolting and flowering. Gibberellin growth hormones (GAs) control stem elongation and reproductive development, but their role during these processes in sugar beet is not defined. We aimed to investigate the involvement of GAs in bolting and flowering in sugar beet, and also its relationship with the vernalization requirement as defined by the B-gene. METHODOLOGY Plants segregating for the B allele were treated with exogenous GA(4) under inductive (16 h light) and non-inductive (8 h light) photoperiods, with and without prior vernalization treatment. A co-dominant polymerase chain reaction (PCR) marker was used to genotype the B-gene locus. Bolting and flowering dates were scored, and bolt heights were measured as appropriate. Analysis of variance was used to determine the effects and interactions of GAs, the B allele and vernalization on bolting and flowering. The effects of the B allele on bolting were also verified in the field. PRINCIPAL RESULTS Application of GAs or the B allele could initiate bolting independently. When the B allele was absent, the applied GAs promoted stem growth, but did so only in vernalized plants, irrespective of photoperiod. Under LDs, bolt height before flowering in plants carrying the B allele (BB; Bb) was not significantly influenced by GAs. The timing and frequency of flowering were influenced by the B allele without interactive effects from GAs. CONCLUSIONS In sugar beet, GA acts independently of the B allele and photoperiod to induce bolting. Vernalization enables GA action independently of the B allele; hence, the dominant B allele may not directly participate in vernalization-induced bolting.
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Affiliation(s)
| | - Aiming Qi
- Broom's Barn Research Centre, Higham, Bury St Edmunds, Suffolk IP28 6NP, UK
| | - Wenying Zhang
- Plant Breeding Institute, Olshausenstr. 40, D-24098 Kiel, Germany
- Current address: Agricultural College, Yangtze University, Jingzhou 434025, Hubei Province, P. R. China
| | | | - Andrea Jennings
- Broom's Barn Research Centre, Higham, Bury St Edmunds, Suffolk IP28 6NP, UK
| | - Uwe Hohmann
- Plant Breeding Institute, Olshausenstr. 40, D-24098 Kiel, Germany
- Current address: Breecon GmbH, Am Mühlenberg 11, 14476 Potsdam-Golm, Germany
| | | | - Peter Hedden
- Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
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Troncoso C, González X, Bömke C, Tudzynski B, Gong F, Hedden P, Rojas MC. Gibberellin biosynthesis and gibberellin oxidase activities in Fusarium sacchari, Fusarium konzum and Fusarium subglutinans strains. Phytochemistry 2010; 71:1322-1331. [PMID: 20570295 DOI: 10.1016/j.phytochem.2010.05.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2009] [Revised: 05/02/2010] [Accepted: 05/07/2010] [Indexed: 05/29/2023]
Abstract
Several isolates of three Fusarium species associated with the Gibberella fujikuroi species complex were characterized for their ability to synthesize gibberellins (GAs): Fusarium sacchari (mating population B), Fusarium konzum (mating population I) and Fusarium subglutinans (mating population E). Of these, F. sacchari is phylogenetically related to Fusarium fujikuroi and is grouped in the Asian clade of the complex, while F. konzum and F. subglutinans are only distantly related to Fusarium fujikuroi and belong to the American clade. Variability was found between the different F. sacchari strains tested. Five isolates (B-12756; B-1732, B-7610, B-1721 and B-1797) were active in GA biosynthesis and accumulated GA(3) in the culture fluid (2.76-28.4 microg/mL), while two others (B-3828 and B-1725) were inactive. GA(3) levels in strain B-12756 increased by 2.9 times upon complementation with ggs2 and cps-ks genes from F. fujikuroi. Of six F. konzum isolates tested, three (I-10653; I-11616; I-11893) synthesized GAs, mainly GA(1), at a low level (less than 0.1 microg/mL). Non-producing F. konzum strains contained no GA oxidase activities as found for the two F. subglutinans strains tested. These results indicate that the ability to produce GAs is present in other species of the G. fujikuroi complex beside F. fujikuroi, but might differ significantly in different isolates of the same species.
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Affiliation(s)
- Claudia Troncoso
- Laboratorio de Bioorgánica, Departamento de Química, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile
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Nitsch LMC, Oplaat C, Feron R, Ma Q, Wolters-Arts M, Hedden P, Mariani C, Vriezen WH. Abscisic acid levels in tomato ovaries are regulated by LeNCED1 and SlCYP707A1. Planta 2009; 229:1335-46. [PMID: 19322584 DOI: 10.1007/s00425-009-0913-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Accepted: 02/19/2009] [Indexed: 05/23/2023]
Abstract
Although the hormones, gibberellin and auxin, are known to play a role in the initiation of fruits, no such function has yet been demonstrated for abscisic acid (ABA). However, ABA signaling and ABA responses are high in tomato (Solanum lycopersicum L.) ovaries before pollination and decrease thereafter (Vriezen et al. in New Phytol 177:60-76, 2008). As a first step to understanding the role of ABA in ovary development and fruit set in tomato, we analyzed ABA content and the expression of genes involved in its metabolism in relation to pollination. We show that ABA levels are relatively high in mature ovaries and decrease directly after pollination, while an increase in the ABA metabolite dihydrophaseic acid was measured. An important regulator of ABA biosynthesis in tomato is 9-cis-epoxy-carotenoid dioxygenase (LeNCED1), whose mRNA level in ovaries is reduced after pollination. The increased catabolism is likely caused by strong induction of one of four newly identified putative (+)ABA 8'-hydroxylase genes. This gene was named SlCYP707A1 and is expressed specifically in ovules and placenta. Transgenic plants, overexpressing SlCYP707A1, have reduced ABA levels and exhibit ABA-deficient phenotypes suggesting that this gene encodes a functional ABA 8'-hydroxylase. Gibberellin and auxin application have different effects on the LeNCED1 and SlCYP707A1 gene expression. The crosstalk between auxins, gibberellins and ABA during fruit set is discussed.
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Affiliation(s)
- Lisette Maria Catharina Nitsch
- Department of Plant Cell Biology, IWWR, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
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Abstract
Gibberellins (GAs) function not only to promote the growth of plant organs, but also to induce phase transitions during development. Their involvement in flower initiation in long-day (LD) and biennial plants is well established and there is growing insight into the mechanisms by which floral induction is achieved. The extent to which GAs mediate the photoperiodic stimulus to flowering in LD plants is, with a few exceptions, less clear. Despite evidence for photoperiod-enhanced GA biosynthesis in leaves of many LD plants, through up-regulation of GA 20-oxidase gene expression, a function for GAs as transmitted signals from leaves to apices in response to LD has been demonstrated only in Lolium species. In Arabidopsis thaliana, as one of four quantitative floral pathways, GA signalling has a relatively minor influence on flowering time in LD, while in SD, in the absence of the photoperiod flowering pathway, the GA pathway assumes a major role and becomes obligatory. Gibberellins promote flowering in Arabidopsis through the activation of genes encoding the floral integrators SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1), LEAFY (LFY), and FLOWERING LOCUS T (FT) in the inflorescence and floral meristems, and in leaves, respectively. Although GA signalling is not required for floral organ specification, it is essential for the normal growth and development of these organs. The sites of GA production and action within flowers, and the signalling pathways involved are beginning to be revealed.
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Affiliation(s)
- Effie Mutasa-Göttgens
- Broom's Barn Research Centre, Rothamsted Research Department of Applied Crop Science, Higham, Bury St Edmunds, Suffolk IP28 6NP, UK
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Bömke C, Rojas MC, Gong F, Hedden P, Tudzynski B. Isolation and characterization of the gibberellin biosynthetic gene cluster in Sphaceloma manihoticola. Appl Environ Microbiol 2008; 74:5325-39. [PMID: 18567680 PMCID: PMC2546651 DOI: 10.1128/aem.00694-08] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Accepted: 06/14/2008] [Indexed: 11/20/2022] Open
Abstract
Gibberellins (GAs) are tetracyclic diterpenoid phytohormones that were first identified as secondary metabolites of the fungus Fusarium fujikuroi (teleomorph, Gibberella fujikuroi). GAs were also found in the cassava pathogen Sphaceloma manihoticola, but the spectrum of GAs differed from that in F. fujikuroi. In contrast to F. fujikuroi, the GA biosynthetic pathway has not been studied in detail in S. manihoticola, and none of the GA biosynthetic genes have been cloned from the species. Here, we present the identification of the GA biosynthetic gene cluster from S. manihoticola consisting of five genes encoding a bifunctional ent-copalyl/ent-kaurene synthase (CPS/KS), a pathway-specific geranylgeranyl diphosphate synthase (GGS2), and three cytochrome P450 monooxygenases. The functions of all of the genes were analyzed either by a gene replacement approach or by complementing the corresponding F. fujikuroi mutants. The cluster organization and gene functions are similar to those in F. fujikuroi. However, the two border genes in the Fusarium cluster encoding the GA(4) desaturase (DES) and the 13-hydroxylase (P450-3) are absent in the S. manihoticola GA gene cluster, consistent with the spectrum of GAs produced by this fungus. The close similarity between the two GA gene clusters, the identical gene functions, and the conserved intron positions suggest a common evolutionary origin despite the distant relatedness of the two fungi.
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Affiliation(s)
- Christiane Bömke
- Westfälische Wilhelms-Universität Münster, Institut für Botanik, Schlossgarten 3, 48149 Münster, Germany
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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. 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] [What about the content of this article? (0)] [Affiliation(s)] [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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