1
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Yang S, Poretska O, Poppenberger B, Sieberer T. ALTERED MERISTEM PROGRAM1 sustains cellular differentiation by limiting HD-ZIP III transcription factor gene expression. Plant Physiol 2024:kiae300. [PMID: 38781290 DOI: 10.1093/plphys/kiae300] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/29/2024] [Accepted: 05/01/2024] [Indexed: 05/25/2024]
Abstract
Plants show remarkable developmental and regenerative plasticity through the sustained activity of stem cells in meristems. Under certain conditions, pluripotency can even be re-established in cells that have already entered differentiation. Mutation of the putative carboxypeptidase ALTERED MERISTEM PROGRAM1 (AMP1) in Arabidopsis (Arabidopsis thaliana) causes a set of hypertrophic phenotypes, indicating a defect in the suppression of pluripotency. A role of AMP1 in the miRNA-mediated inhibition of translation has previously been reported, however, how this activity is related to its developmental functions is unclear. Here we examined the functional interaction between AMP1 and the Class III homeodomain-leucine zipper (HD-ZIP III) transcription factors, which are miRNA-controlled determinants of shoot meristem specification. We found that the HD-ZIP III transcriptional output is enhanced in the amp1 mutant and that plant lines with increased HD-ZIP III activity not only developed amp1 mutant-like phenotypes but also showed a synergistic genetic interaction with the mutant. Conversely, the reduction of HD-ZIP III function suppressed the shoot hypertrophy defects of the amp1 mutant. We further provide evidence that the expression domains of HD-ZIP III family members are expanded in the amp1 mutant and that this misexpression occurs at the transcriptional level and does not involve the function of miRNA165/166. Finally, amp1 mutant-specific phenotypes cannot be mimicked by a general inhibition of miRNA function in the AMP1 expression domain. These findings lead us to a model in which AMP1 restricts cellular pluripotency upstream of HD-ZIP III proteins and this control appears to be not directly mediated by the canonical miRNA pathway.
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Affiliation(s)
- Saiqi Yang
- Research Unit Plant Growth Regulation, TUM School of Life Sciences, Technical University of Munich, DE-85354, Freising, Germany
| | - Olena Poretska
- Research Unit Plant Growth Regulation, TUM School of Life Sciences, Technical University of Munich, DE-85354, Freising, Germany
| | - Brigitte Poppenberger
- Professorship Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Tobias Sieberer
- Research Unit Plant Growth Regulation, TUM School of Life Sciences, Technical University of Munich, DE-85354, Freising, Germany
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2
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Rozhon W, Ramirez VE, Wieckhorst S, Hahn V, Poppenberger B. Generation of high oleic acid sunflower lines using gamma radiation mutagenesis and high-throughput fatty acid profiling. Front Plant Sci 2023; 14:1138603. [PMID: 38023891 PMCID: PMC10679672 DOI: 10.3389/fpls.2023.1138603] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 10/25/2023] [Indexed: 12/01/2023]
Abstract
Sunflower (Helianthus annuus L.) is the second most important oil seed crop in Europe. The seeds are used as confection seeds and, more importantly, to generate an edible vegetable oil, which in normal varieties is rich in the polyunsaturated fatty acid linoleic acid. Linoleic acid is biosynthesized from oleic acid through activity of the oleate desaturase FATTY ACID DESATURASE 2 (FAD2), which in seeds is encoded by FAD2-1, a gene that's present in single copy in sunflowers. Defective FAD2-1 expression enriches oleic acid, yielding the high oleic (HO) acid trait, which is of great interest in oil seed crops, since HO oil bears benefits for both food and non-food applications. Chemical mutagenesis has previously been used to generate sunflower mutants with reduced FAD2-1 expression and here it was aimed to produce further genetic material in which FAD2-1 activity is lost and the HO trait is stably expressed. For this purpose, a sunflower mutant population was created using gamma irradiation and screened for fad2-1 mutants with a newly developed HPLC-based fatty-acid profiling system that's suitable for high-throughput analyses. With this approach fad2-1 knock-out mutants could be isolated, which stably hyper-accumulate oleic acid in concentrations of 85-90% of the total fatty acid pool. The genetic nature of these new sunflower lines was characterized and will facilitate marker development, for the rapid introgression of the trait into elite sunflower breeding material.
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Affiliation(s)
- Wilfried Rozhon
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Veronica E. Ramirez
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | | | - Volker Hahn
- Landessaatzuchtanstalt, University of Hohenheim, Willstätt, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
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3
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Yang S, de Haan M, Mayer J, Janacek DP, Hammes UZ, Poppenberger B, Sieberer T. A novel chemical inhibitor of polar auxin transport promotes shoot regeneration by local enhancement of HD-ZIP III transcription. New Phytol 2022; 235:1111-1128. [PMID: 35491431 DOI: 10.1111/nph.18196] [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] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 04/21/2022] [Indexed: 06/14/2023]
Abstract
De novo shoot organogenesis is a prerequisite for numerous applications in plant research and breeding but is often a limiting factor, for example, in genome editing approaches. Class III homeodomain-leucine zipper (HD-ZIP III) transcription factors have been characterized as crucial regulators of shoot specification, however up-stream components controlling their activity during shoot regeneration are only partially identified. In a chemical genetic screen, we isolated ZIC2, a novel activator of HD-ZIP III activity. Using molecular, physiological and hormone transport analyses in Arabidopsis and sunflower (Helianthus annuus), we examined the molecular mechanism by which the drug promotes HD-ZIP III expression. ZIC2-dependent upregulation of HD-ZIP III transcription promotes shoot regeneration in Arabidopsis and is accompanied by the induction of shoot specifying factors WUS and RAP2.6L and a subset of cytokinin biosynthesis enzymes. ZIC2's effect on HD-ZIP III expression and regeneration is based on its ability to limit polar auxin transport. We further provide evidence that chemical modulation of auxin efflux can enhance de novo shoot formation in the regeneration recalcitrant species sunflower. Activation of HD-ZIP III transcription during shoot regeneration depends on the local distribution of auxin and chemical modulation of auxin transport can be used to overcome poor shoot organogenesis in tissue culture.
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Affiliation(s)
- Saiqi Yang
- Research Unit Plant Growth Regulation, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
| | - Marjolein de Haan
- Research Unit Plant Growth Regulation, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
| | - Julius Mayer
- Research Unit Plant Growth Regulation, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
| | - Dorina P Janacek
- Plant Systems Biology, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
| | - Ulrich Z Hammes
- Plant Systems Biology, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
| | - Tobias Sieberer
- Research Unit Plant Growth Regulation, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
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4
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Shuai H, Chen T, Wlk T, Rozhon W, Pimenta Lange MJ, Sieberer T, Lange T, Poppenberger B. SlCESTA Is a Brassinosteroid-Regulated bHLH Transcription Factor of Tomato That Promotes Chilling Tolerance and Fruit Growth When Over-Expressed. Front Plant Sci 2022; 13:930805. [PMID: 35909777 PMCID: PMC9337221 DOI: 10.3389/fpls.2022.930805] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/08/2022] [Indexed: 06/15/2023]
Abstract
Brassinosteroids (BRs) are required for various aspects of plant growth and development, but also participate in stress responses. The hormones convey their activity through transcriptional regulation and posttranslational modification of transcription factors and one class are basic helix-loop-helix (bHLH) proteins of the BR Enhanced Expression (BEE) subfamily, which in Arabidopsis thaliana include BEE1-3 and CESTA (CES). CES and the BEEs promote the expression of different BR-responsive genes, including genes encoding gibberellin (GA) biosynthetic and catabolizing enzymes, as well as cold-responsive genes. Interestingly, in terms of an application, CES could promote both fruit growth and cold stress tolerance when over-expressed in A. thaliana and here it was investigated, if this function is conserved in the fruit crop Solanum lycopersicum (cultivated tomato). Based on amino acid sequence similarity and the presence of regulatory motifs, a CES orthologue of S. lycopersicum, SlCES, was identified and the effects of its over-expression were analysed in tomato. This showed that SlCES, like AtCES, was re-localized to nuclear bodies in response to BR signaling activation and that it effected GA homeostasis, with related phenotypes, when over-expressed. In addition, over-expression lines showed an increased chilling tolerance and had altered fruit characteristics. The possibilities and potential limitations of a gain of SlCES function as a breeding strategy for tomato are discussed.
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Affiliation(s)
- Haiwei Shuai
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Tingting Chen
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Tanja Wlk
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Wilfried Rozhon
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | | | - Tobias Sieberer
- Plant Growth Regulation, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Theo Lange
- Institute of Plant Biology, Technical University of Braunschweig, Braunschweig, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
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5
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Adedeji-Badmus AN, Schramm S, Gigl M, Iwebema W, Albertos P, Dawid C, Sieberer T, Poppenberger B. Species-Specific Variation in Abscisic Acid Homeostasis and Responses Impacts Important Traits in Crassocephalum Orphan Crops. Front Plant Sci 2022; 13:923421. [PMID: 35903235 PMCID: PMC9318166 DOI: 10.3389/fpls.2022.923421] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 06/02/2022] [Indexed: 06/15/2023]
Abstract
Crassocephalum rubens and Crassocephalum crepidioides are plant species native to Africa, but grow in most tropical and subtropical regions of the world. They are rich in vitamins, minerals, and essential oils and are traditional leafy vegetables and medicinal plants in Sub-Saharan Africa. The plants are still mainly collected from the wild but shall be taken into cultivation and an important aim in the domestication of these species is to improve traits that are relevant for crop production. Here, seed formation and germination capacities in C. crepidioides and C. rubens were investigated, and it was found that C. crepidioides exhibits a higher level of seed dormancy, which could be broken with light, and was correlated with higher amounts of abscisic acid (ABA), a plant hormone that promotes seed dormancy. ABA is also very well-known for its role in abiotic stress tolerance, and it is shown that tetraploid C. crepidioides exhibits a higher level of resistance against drought and heat stress than diploid C. rubens, traits that will benefit the cultivation of these plants, particularly in rain-fed cropping systems. The potential of Crassocephalum to improve nutrition and increase the resilience of marginal cropping systems in Africa is discussed.
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Affiliation(s)
- Adebimpe N. Adedeji-Badmus
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Sebastian Schramm
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Michael Gigl
- Chair of Food Chemistry and Molecular Sensory Science, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Williams Iwebema
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Pablo Albertos
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Corinna Dawid
- Chair of Food Chemistry and Molecular Sensory Science, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Tobias Sieberer
- Research Group Plant Growth Regulation, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
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6
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Albertos P, Wlk T, Griffiths J, Pimenta Lange MJ, Unterholzner SJ, Rozhon W, Lange T, Jones AM, Poppenberger B. Brassinosteroid-regulated bHLH transcription factor CESTA induces the gibberellin 2-oxidase GA2ox7. Plant Physiol 2022; 188:2012-2025. [PMID: 35148416 PMCID: PMC8968292 DOI: 10.1093/plphys/kiac008] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 12/10/2021] [Indexed: 05/14/2023]
Abstract
Brassinosteroids (BRs) are plant steroids that have growth-promoting capacities, which are partly enabled by an ability to induce biosynthesis of gibberellins (GAs), a second class of plant hormones. In addition, BRs can also activate GA catabolism; here we show that in Arabidopsis (Arabidopsis thaliana) the basic helix-loop-helix transcription factor CESTA (CES) and its homologues BRASSINOSTEROID-ENHANCED EXPRESSION (BEE) 1 and 3 contribute to this activity. CES and the BEEs are BR-regulated at the transcriptional and posttranslational level and participate in different physiological processes, including vegetative and reproduction development, shade avoidance, and cold stress responses. We show that CES/BEEs can induce the expression of the class III GA 2-oxidase GA2ox7 and that this activity is increased by BRs. In BR signaling - and CES/BEE-deficient mutants, GA2ox7 expression decreased, yielding reduced levels of GA110, a product of GA2ox7 activity. In plants that over-express CES, GA2ox7 expression is hyper-responsive to BR, GA110 levels are elevated and amounts of bioactive GA are reduced. We provide evidence that CES directly binds to the GA2ox7 promoter and is activated by BRs, but can also act by BR-independent means. Based on these results, we propose a model for CES activity in GA catabolism where CES can be recruited for GA2ox7 induction not only by BR, but also by other factors.
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Affiliation(s)
| | | | | | - Maria J Pimenta Lange
- Institute of Plant Biology, Technical University of Braunschweig, Braunschweig, Germany
| | | | | | - Theo Lange
- Institute of Plant Biology, Technical University of Braunschweig, Braunschweig, Germany
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7
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Albertos P, Dündar G, Schenk P, Carrera S, Cavelius P, Sieberer T, Poppenberger B. Transcription factor BES1 interacts with HSFA1 to promote heat stress resistance of plants. EMBO J 2022; 41:e108664. [PMID: 34981847 PMCID: PMC8804921 DOI: 10.15252/embj.2021108664] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 12/05/2021] [Accepted: 12/08/2021] [Indexed: 12/18/2022] Open
Abstract
Heat stress is a major environmental stress type that can limit plant growth and development. To survive sudden temperature increases, plants utilize the heat shock response, an ancient signaling pathway. Initial results had suggested a role for brassinosteroids (BRs) in this response. Brassinosteroids are growth-promoting steroid hormones whose activity is mediated by transcription factors of the BES1/BZR1 subfamily. Here, we provide evidence that BES1 can contribute to heat stress signaling. In response to heat, BES1 is activated even in the absence of BRs and directly binds to heat shock elements (HSEs), known binding sites of heat shock transcription factors (HSFs). HSFs of the HSFA1 type can interact with BES1 and facilitate its activity in HSE binding. These findings lead us to propose an extended model of the heat stress response in plants, in which the recruitment of BES1 is a means of heat stress signaling cross-talk with a central growth regulatory pathway.
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Affiliation(s)
- Pablo Albertos
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Gönül Dündar
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Philipp Schenk
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Sergio Carrera
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Philipp Cavelius
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Tobias Sieberer
- Plant Growth Regulation, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
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8
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Schramm S, Rozhon W, Adedeji-Badmus AN, Liang Y, Nayem S, Winkelmann T, Poppenberger B. The Orphan Crop Crassocephalum crepidioides Accumulates the Pyrrolizidine Alkaloid Jacobine in Response to Nitrogen Starvation. Front Plant Sci 2021; 12:702985. [PMID: 34394157 PMCID: PMC8355542 DOI: 10.3389/fpls.2021.702985] [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] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
Crassocephalum crepidioides is an African orphan crop that is used as a leafy vegetable and medicinal plant. Although it is of high regional importance in Sub-Saharan Africa, the plant is still mainly collected from the wild and therefore efforts are made to promote its domestication. However, in addition to beneficial properties, there was first evidence that C. crepidioides can accumulate the highly toxic pyrrolizidine alkaloid (PA) jacobine and here it was investigated, how jacobine production is controlled. Using ecotypes from Africa and Asia that were characterized in terms of their PA profiles, it is shown that the tetraploid C. crepidioides forms jacobine, an ability that its diploid close relative Crassocephalum rubens appears to lack. Evidence is provided that nitrogen (N) deficiency strongly increases jacobine in the leaves of C. crepidioides, that this capacity depends more strongly on the shoot than the root system, and that homospermidine synthase (HSS) activity is not rate-limiting for this reaction. A characterization of HSS gene representation and transcription showed that C. crepidioides and C. rubens possess two functional versions, one of which is conserved, that the HSS transcript is mainly present in roots and that its abundance is not controlled by N deficiency. In summary, this work improves our understanding of how environmental cues impact PA biosynthesis in plants and provides a basis for the development of PA-free C. crepidioides cultivars, which will aid its domestication and safe use.
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Affiliation(s)
- Sebastian Schramm
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Wilfried Rozhon
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Adebimpe N. Adedeji-Badmus
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Yuanyuan Liang
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Shahran Nayem
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Traud Winkelmann
- Woody Plant and Propagation Physiology Section, Institute of Horticultural Production Systems, Gottfried Wilhelm Leibniz University Hannover, Hanover, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
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9
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Gan S, Rozhon W, Varga E, Halder J, Berthiller F, Poppenberger B. The acyltransferase PMAT1 malonylates brassinolide glucoside. J Biol Chem 2021; 296:100424. [PMID: 33600798 PMCID: PMC8010461 DOI: 10.1016/j.jbc.2021.100424] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 02/04/2021] [Accepted: 02/12/2021] [Indexed: 12/01/2022] Open
Abstract
Brassinosteroids (BRs) are steroid hormones of plants that coordinate fundamental growth and development processes. Their homeostasis is controlled by diverse means, including glucosylation of the bioactive BR brassinolide (BL), which is catalyzed by the UDP-glycosyltransferases (UGTs) UGT73C5 and UGT73C6 and occurs mainly at the C-23 position. Additional evidence had suggested that the resultant BL-23-O-glucoside (BL-23-O-Glc) can be malonylated, but the physiological significance of and enzyme required for this reaction had remained unknown. Here, we show that in Arabidopsis thaliana malonylation of BL-23-O-Glc is catalyzed by the acyltransferase phenolic glucoside malonyl-transferase 1 (PMAT1), which is also known to malonylate phenolic glucosides and lipid amides. Loss of PMAT1 abolished BL-23-O-malonylglucoside formation and enriched BL-23-O-Glc, showing that the enzyme acts on the glucoside. An overexpression of PMAT1 in plants where UGT73C6 was also overexpressed, and thus, BL-23-O-Glc formation was promoted, enhanced the symptoms of BR-deficiency of UGT73C6oe plants, providing evidence that PMAT1 contributes to BL inactivation. Based on these results, a model is proposed in which PMAT1 acts in the conversion of both endogenous and xenobiotic glucosides to adjust metabolic homeostasis in spatial and temporal modes.
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Affiliation(s)
- Sufu Gan
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, Freising, Germany
| | - Wilfried Rozhon
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, Freising, Germany
| | - Elisabeth Varga
- Institute of Bioanalytics and Agro-Metabolomics, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna, Tulln, Austria
| | - Jyotirmoy Halder
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, Freising, Germany
| | - Franz Berthiller
- Institute of Bioanalytics and Agro-Metabolomics, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna, Tulln, Austria
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, Freising, Germany.
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10
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Ramirez VE, Poppenberger B. Modes of Brassinosteroid Activity in Cold Stress Tolerance. Front Plant Sci 2020; 11:583666. [PMID: 33240301 PMCID: PMC7677411 DOI: 10.3389/fpls.2020.583666] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 10/09/2020] [Indexed: 06/11/2023]
Abstract
Cold stress is a significant environmental factor that negatively affects plant growth and development in particular when it occurs during the growth phase. Plants have evolved means to protect themselves from damage caused by chilling or freezing temperatures and some plant species, in particular those from temperate geographical zones, can increase their basal level of freezing tolerance in a process termed cold acclimation. Cold acclimation improves plant survival, but also represses growth, since it inhibits activity of the growth-promoting hormones gibberellins (GAs). In addition to GAs, the steroid hormones brassinosteroids (BRs) also take part in growth promotion and cold stress signaling; however, in contrast to Gas, BRs can improve cold stress tolerance with fewer trade-offs in terms of growth and yields. Here we summarize our current understanding of the roles of BRs in cold stress responses with a focus on freezing tolerance and cold acclimation pathways.
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11
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Gan S, Rozhon W, Varga E, Unterholzner SJ, Berthiller F, Poppenberger B. The BAHD Acyltransferase BIA1 Uses Acetyl-CoA for Catabolic Inactivation of Brassinosteroids. Plant Physiol 2020; 184:23-26. [PMID: 32611786 PMCID: PMC7479910 DOI: 10.1104/pp.20.00338] [Citation(s) in RCA: 4] [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: 03/17/2020] [Accepted: 06/23/2020] [Indexed: 05/20/2023]
Abstract
Previous research complemented with results on BIA1 enzymatic activities shows that the enzyme regulates brassinosteroid homeostasis via mono- and diacetylation of castasterone
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Affiliation(s)
- Sufu Gan
- Biotechnology of Horticultural Crops, Technische Universität München School for Life Sciences Weihenstephan, D-85354 Freising, Germany
| | - Wilfried Rozhon
- Biotechnology of Horticultural Crops, Technische Universität München School for Life Sciences Weihenstephan, D-85354 Freising, Germany
| | - Elisabeth Varga
- Institute of Bioanalytics and Agro-Metabolomics, Department of Agrobiotechnology, University of Natural Resources and Life Sciences, Vienna, Tulln 3430, Austria
| | - Simon Josef Unterholzner
- Biotechnology of Horticultural Crops, Technische Universität München School for Life Sciences Weihenstephan, D-85354 Freising, Germany
| | - Franz Berthiller
- Institute of Bioanalytics and Agro-Metabolomics, Department of Agrobiotechnology, University of Natural Resources and Life Sciences, Vienna, Tulln 3430, Austria
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, Technische Universität München School for Life Sciences Weihenstephan, D-85354 Freising, Germany
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12
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Poretska O, Yang S, Pitorre D, Poppenberger B, Sieberer T. AMP1 and CYP78A5/7 act through a common pathway to govern cell fate maintenance in Arabidopsis thaliana. PLoS Genet 2020; 16:e1009043. [PMID: 32960882 PMCID: PMC7531801 DOI: 10.1371/journal.pgen.1009043] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 10/02/2020] [Accepted: 08/11/2020] [Indexed: 12/17/2022] Open
Abstract
Higher plants can continuously form new organs by the sustained activity of pluripotent stem cells. These stem cells are embedded in meristems, where they produce descendants, which undergo cell proliferation and differentiation programs in a spatiotemporally-controlled manner. Under certain conditions, pluripotency can be reestablished in descending cells and this reversion in cell fate appears to be actively suppressed by the existing stem cell pool. Mutation of the putative carboxypeptidase ALTERED MERISTEM PROGRAM1 (AMP1) in Arabidopsis causes defects in the suppression of pluripotency in cells normally programmed for differentiation, giving rise to unique hypertrophic phenotypes during embryogenesis as well as in the shoot apical meristem. A role of AMP1 in the miRNA-dependent control of translation has recently been established, however, how this activity is connected to its developmental functions is not resolved. Here we identify members of the cytochrome P450 clade CYP78A to act in parallel with AMP1 to control cell fate in Arabidopsis. Mutation of CYP78A5 and its close homolog CYP78A7 in a cyp78a5,7 double mutant caused suspensor-to-embryo conversion and ectopic stem cell pool formation in the shoot meristem, phenotypes characteristic for amp1. The tissues affected in the mutants showed pronounced expression levels of AMP1 and CYP78A5 in wild type. A comparison of mutant transcriptomic responses revealed an intriguing degree of overlap and highlighted alterations in protein lipidation processes. Moreover, we also found elevated protein levels of selected miRNA targets in cyp78a5,7. Based on comprehensive genetic interaction studies we propose a model in which both enzyme classes act on a common downstream process to sustain cell fate decisions in the early embryo and the shoot apical meristem.
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Affiliation(s)
- Olena Poretska
- Research Unit Plant Growth Regulation, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
- Department for Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Saiqi Yang
- Research Unit Plant Growth Regulation, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Delphine Pitorre
- Department for Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Tobias Sieberer
- Research Unit Plant Growth Regulation, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
- Department for Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
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13
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Nowicka A, Tokarz B, Zwyrtková J, Dvořák Tomaštíková E, Procházková K, Ercan U, Finke A, Rozhon W, Poppenberger B, Otmar M, Niezgodzki I, Krečmerová M, Schubert I, Pecinka A. Comparative analysis of epigenetic inhibitors reveals different degrees of interference with transcriptional gene silencing and induction of DNA damage. Plant J 2020; 102:68-84. [PMID: 31733119 DOI: 10.1111/tpj.14612] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/25/2019] [Accepted: 10/29/2019] [Indexed: 06/10/2023]
Abstract
Repetitive DNA sequences and some genes are epigenetically repressed by transcriptional gene silencing (TGS). When genetic mutants are not available or problematic to use, TGS can be suppressed by chemical inhibitors. However, informed use of epigenetic inhibitors is partially hampered by the absence of any systematic comparison. In addition, there is emerging evidence that epigenetic inhibitors cause genomic instability, but the nature of this damage and its repair remain unclear. To bridge these gaps, we compared the effects of 5-azacytidine (AC), 2'-deoxy-5-azacytidine (DAC), zebularine and 3-deazaneplanocin A (DZNep) on TGS and DNA damage repair. The most effective inhibitor of TGS was DAC, followed by DZNep, zebularine and AC. We confirmed that all inhibitors induce DNA damage and suggest that this damage is repaired by multiple pathways with a critical role of homologous recombination and of the SMC5/6 complex. A strong positive link between the degree of cytidine analog-induced DNA demethylation and the amount of DNA damage suggests that DNA damage is an integral part of cytidine analog-induced DNA demethylation. This helps us to understand the function of DNA methylation in plants and opens the possibility of using epigenetic inhibitors in biotechnology.
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Affiliation(s)
- Anna Nowicka
- Institute of Experimental Botany (IEB), Czech Academy of Sciences, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), CZ-779 00, Olomouc, Czech Republic
- Max Planck Institute for Plant Breeding Research (MPIPZ), DE-50829, Cologne, Germany
- The Polish Academy of Sciences, The Franciszek Górski Institute of Plant Physiology, Niezapominajek 21, PL-30 239, Krakow, Poland
| | - Barbara Tokarz
- Institute of Experimental Botany (IEB), Czech Academy of Sciences, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), CZ-779 00, Olomouc, Czech Republic
- Unit of Botany and Plant Physiology, Institute of Plant Biology and Biotechnology, Faculty of Biotechnology and Horticulture, University of Agriculture in Krakow, Al. 29 Listopada 54, PL-31 425, Krakow, Poland
| | - Jana Zwyrtková
- Institute of Experimental Botany (IEB), Czech Academy of Sciences, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), CZ-779 00, Olomouc, Czech Republic
| | - Eva Dvořák Tomaštíková
- Institute of Experimental Botany (IEB), Czech Academy of Sciences, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), CZ-779 00, Olomouc, Czech Republic
| | - Klára Procházková
- Institute of Experimental Botany (IEB), Czech Academy of Sciences, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), CZ-779 00, Olomouc, Czech Republic
| | - Ugur Ercan
- Max Planck Institute for Plant Breeding Research (MPIPZ), DE-50829, Cologne, Germany
| | - Andreas Finke
- Max Planck Institute for Plant Breeding Research (MPIPZ), DE-50829, Cologne, Germany
| | - Wilfried Rozhon
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 1, DE-85354, Freising, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 1, DE-85354, Freising, Germany
| | - Miroslav Otmar
- Institute of Organic Chemistry and Biochemistry, CZ-166 10, Praha 6, Czech Republic
| | - Igor Niezgodzki
- Biogeosystem Modelling Group, ING PAN - Institute of Geological Sciences Polish Academy of Sciences, Research Center in Krakow, Senacka 1, PL-31 002, Krakow, Poland
| | - Marcela Krečmerová
- Institute of Organic Chemistry and Biochemistry, CZ-166 10, Praha 6, Czech Republic
| | - Ingo Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research, Stadt Seeland, DE-06466, Gatersleben, OT, Germany
| | - Ales Pecinka
- Institute of Experimental Botany (IEB), Czech Academy of Sciences, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), CZ-779 00, Olomouc, Czech Republic
- Max Planck Institute for Plant Breeding Research (MPIPZ), DE-50829, Cologne, Germany
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14
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Rozhon W, Akter S, Fernandez A, Poppenberger B. Inhibitors of Brassinosteroid Biosynthesis and Signal Transduction. Molecules 2019; 24:E4372. [PMID: 31795392 PMCID: PMC6930552 DOI: 10.3390/molecules24234372] [Citation(s) in RCA: 15] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 11/25/2019] [Accepted: 11/26/2019] [Indexed: 12/19/2022] Open
Abstract
Chemical inhibitors are invaluable tools for investigating protein function in reverse genetic approaches. Their application bears many advantages over mutant generation and characterization. Inhibitors can overcome functional redundancy, their application is not limited to species for which tools of molecular genetics are available and they can be applied to specific tissues or developmental stages, making them highly convenient for addressing biological questions. The use of inhibitors has helped to elucidate hormone biosynthesis and signaling pathways and here we review compounds that were developed for the plant hormones brassinosteroids (BRs). BRs are steroids that have strong growth-promoting capacities, are crucial for all stages of plant development and participate in adaptive growth processes and stress response reactions. In the last two decades, impressive progress has been made in BR inhibitor development and application, which has been instrumental for studying BR modes of activity and identifying and characterizing key players. Both, inhibitors that target biosynthesis, such as brassinazole, and inhibitors that target signaling, such as bikinin, exist and in a comprehensive overview we summarize knowledge and methodology that enabled their design and key findings of their use. In addition, the potential of BR inhibitors for commercial application in plant production is discussed.
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Affiliation(s)
- Wilfried Rozhon
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 1, 85354 Freising, Germany
| | | | | | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 1, 85354 Freising, Germany
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15
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Albertos P, Wagner K, Poppenberger B. Cold stress signalling in female reproductive tissues. Plant Cell Environ 2019; 42:846-853. [PMID: 30043473 DOI: 10.1111/pce.13408] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 06/29/2018] [Accepted: 07/10/2018] [Indexed: 05/20/2023]
Abstract
Cold stress is a significant threat for plant productivity and impacts on plant distribution and crop production, particularly so when it occurs during the growth phase. A developmental stage at risk is that of flowering, since a single stress event during sensitive stages, such as the full-bloom stage of fruit trees can be fatal for reproductive success. Although pollen development and fertilization are widely viewed as the most critical reproductive phases, the development and function of female reproductive tissues, which in Angiosperms are embedded in the gynoecium, are also affected by cold stress. Today however, we have essentially no understanding of the cold stress response pathways that act during floral organogenesis. In this review, we briefly summarize our current knowledge of cold stress signalling modules active in vegetative tissues that may provide a framework of general principles also transferable to female reproductive tissues. We then align these signalling cascades with those that govern gynoecium development to identify factors that may act in both processes and could thereby contribute to cold stress responses in female reproductive tissues.
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Affiliation(s)
- Pablo Albertos
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Konstantin Wagner
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
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16
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Avramova V, Meziane A, Bauer E, Blankenagel S, Eggels S, Gresset S, Grill E, Niculaes C, Ouzunova M, Poppenberger B, Presterl T, Rozhon W, Welcker C, Yang Z, Tardieu F, Schön CC. Carbon isotope composition, water use efficiency, and drought sensitivity are controlled by a common genomic segment in maize. Theor Appl Genet 2019; 132:53-63. [PMID: 30244394 PMCID: PMC6320357 DOI: 10.1007/s00122-018-3193-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 09/15/2018] [Indexed: 05/21/2023]
Abstract
KEY MESSAGE A genomic segment on maize chromosome 7 influences carbon isotope composition, water use efficiency, and leaf growth sensitivity to drought, possibly by affecting stomatal properties. Climate change is expected to decrease water availability in many agricultural production areas around the globe. Therefore, plants with improved ability to grow under water deficit are urgently needed. We combined genetic, phenomic, and physiological approaches to understand the relationship between growth, stomatal conductance, water use efficiency, and carbon isotope composition in maize (Zea mays L.). Using near-isogenic lines derived from a maize introgression library, we analysed the effects of a genomic region previously identified as affecting carbon isotope composition. We show stability of trait expression over several years of field trials and demonstrate in the phenotyping platform Phenodyn that the same genomic region also influences the sensitivity of leaf growth to evaporative demand and soil water potential. Our results suggest that the studied genomic region affecting carbon isotope discrimination also harbours quantitative trait loci playing a role in maize drought sensitivity possibly via stomatal behaviour and development. We propose that the observed phenotypes collectively originate from altered stomatal conductance, presumably via abscisic acid.
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Affiliation(s)
- Viktoriya Avramova
- Plant Breeding, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 2, 85354, Freising, Germany
| | - Adel Meziane
- INRA, UMR759 Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, Place Viala, 34060, Montpellier, France
| | - Eva Bauer
- Plant Breeding, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 2, 85354, Freising, Germany
| | - Sonja Blankenagel
- Plant Breeding, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 2, 85354, Freising, Germany
| | - Stella Eggels
- Plant Breeding, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 2, 85354, Freising, Germany
| | - Sebastian Gresset
- Plant Breeding, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 2, 85354, Freising, Germany
| | - Erwin Grill
- Botany, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Emil-Ramann-Straße 4, 85354, Freising, Germany
| | - Claudiu Niculaes
- Plant Breeding, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 2, 85354, Freising, Germany
| | | | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 1, 85354, Freising, Germany
| | | | - Wilfried Rozhon
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 1, 85354, Freising, Germany
| | - Claude Welcker
- INRA, UMR759 Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, Place Viala, 34060, Montpellier, France
| | - Zhenyu Yang
- Botany, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Emil-Ramann-Straße 4, 85354, Freising, Germany
| | - François Tardieu
- INRA, UMR759 Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, Place Viala, 34060, Montpellier, France
| | - Chris-Carolin Schön
- Plant Breeding, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 2, 85354, Freising, Germany.
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17
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Abstract
Sugar and organic acid contents are major factors for tomato fruit flavour and are important breeding traits. Here we provide an improved protocol for accurate quantification of the main sugars, glucose and fructose, and the organic acids, citric acid and malic acid, present in tomato. The tomato extract is spiked with lactose and tricarballylic acid as internal standards and loaded onto a NH2 solid phase extraction (SPE) column. The sugars appear in the flow-through and are subsequently analysed by HPLC using a Nucleodur NH2 column and a refractive index detector. The organic acids bind to the SPE column and are eluted with 400 mM phosphoric acid. For analysis, the organic acids are separated by HPLC using a Nucleodur C18ec column and detected by UV absorption at 210 nm. The method shows excellent inter-day and intra-day reproducibility for glucose, fructose and citric acid with standard deviations of 1–5%. Quantification of citric acid by HPLC and GC–MS showed perfect agreement with a deviation of less than 3%. Simple method for quantification of glucose, fructose, citric acid and malic acid in tomato. Efficient removal of interfering compounds by solid phase extraction. High intra and inter-day reproducibility.
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Affiliation(s)
- Carlos Agius
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 1, 85354 Freising, Germany.,Chair of Plant Nutrition, Department of Plant Sciences, TUM School of Life Sciences Weihenstephan, Technical University of Munich Emil-Ramann-Straße 2, 85350 Freising, Germany
| | - Sabine von Tucher
- Chair of Plant Nutrition, Department of Plant Sciences, TUM School of Life Sciences Weihenstephan, Technical University of Munich Emil-Ramann-Straße 2, 85350 Freising, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 1, 85354 Freising, Germany
| | - Wilfried Rozhon
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 1, 85354 Freising, Germany
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18
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Abstract
Plants in temperate climates utilize cold acclimation modes to improve frost tolerance during phases of active growth. Two papers in this issue of Developmental Cell (Li et al., 2017; Zhao et al., 2017) now highlight the important role MAP kinases play in this process in Arabidopsis thaliana.
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Affiliation(s)
- Veronica E Ramirez
- Biotechnology of Horticultural Crops, School for Life Sciences Weihenstephan, Technical University Munich, 85354 Freising, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, School for Life Sciences Weihenstephan, Technical University Munich, 85354 Freising, Germany.
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19
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Rozhon W, Kammermeier L, Schramm S, Towfique N, Adebimpe Adedeji N, Adesola Ajayi S, Poppenberger B. Quantification of the Pyrrolizidine Alkaloid Jacobine in Crassocephalum crepidioides by Cation Exchange High-Performance Liquid Chromatography. Phytochem Anal 2018; 29:48-58. [PMID: 28836707 DOI: 10.1002/pca.2713] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 07/03/2017] [Accepted: 07/04/2017] [Indexed: 06/07/2023]
Abstract
INTRODUCTION Pyrrolizidine alkaloids (PAs) are secondary plant metabolites with considerable hepatoxic, tumorigenic and genotoxic potential. For separation, reversed phase chromatography is commonly used because of its excellent compatibility with detection by mass spectrometry. However, reversed phase chromatography has a low selectivity for PAs. OBJECTIVE The objective of this work was to investigate the suitability of cation exchange chromatography for separation of PAs and to develop a rapid method for quantification of jacobine in Crassocephalum crepidioides that is suitable for analysis of huge sample numbers as required for mutant screening procedures. RESULTS We demonstrate that cation exchange chromatography offers excellent selectivity for PAs allowing their separation from most other plant metabolites. Due to the high selectivity, plant extracts can be directly analysed after simple sample preparation. Detection with UV at 200 nm instead of mass spectrometry can be applied, which makes the method very simple and cost-effective. The recovery rate of the method exceeded 95%, the intra-day and inter-day standard deviations were below 7% and the limit of detection and quantification were 1 mg/kg and 3 mg/kg, respectively. CONCLUSION The developed method is sufficiently sensitive for reproducible detection of jacobine in C. crepidioides. Simple sample preparation and rapid separation allows for quantification of jacobine in plant material in a high-throughput manner. Thus, the method is suitable for genetic screenings and may be applicable for other plant species, for instance Jacobaea maritima. In addition, our results show that C. crepidioides cannot be considered safe for human consumption. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
- Wilfried Rozhon
- Biotechnology of Horticultural Crops, Technische Universität München, Liesel-Beckmann-Straße 1, 85354, Freising-Weihenstephan, Germany
| | - Lukas Kammermeier
- Biotechnology of Horticultural Crops, Technische Universität München, Liesel-Beckmann-Straße 1, 85354, Freising-Weihenstephan, Germany
| | - Sebastian Schramm
- Biotechnology of Horticultural Crops, Technische Universität München, Liesel-Beckmann-Straße 1, 85354, Freising-Weihenstephan, Germany
| | - Nayeem Towfique
- Biotechnology of Horticultural Crops, Technische Universität München, Liesel-Beckmann-Straße 1, 85354, Freising-Weihenstephan, Germany
| | - N Adebimpe Adedeji
- Department of Crop Production and Protection, Obafemi Awolowo University, PMB 013, Ilé-Ifè, 220005, Nigeria
| | - S Adesola Ajayi
- Department of Crop Production and Protection, Obafemi Awolowo University, PMB 013, Ilé-Ifè, 220005, Nigeria
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, Technische Universität München, Liesel-Beckmann-Straße 1, 85354, Freising-Weihenstephan, Germany
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20
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Poretska O, Yang S, Pitorre D, Rozhon W, Zwerger K, Uribe MC, May S, McCourt P, Poppenberger B, Sieberer T. The Small Molecule Hyperphyllin Enhances Leaf Formation Rate and Mimics Shoot Meristem Integrity Defects Associated with AMP1 Deficiency. Plant Physiol 2016; 171:1277-90. [PMID: 27208298 PMCID: PMC4902576 DOI: 10.1104/pp.15.01633] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 05/01/2016] [Indexed: 05/03/2023]
Abstract
ALTERED MERISTEM PROGRAM1 (AMP1) is a member of the M28 family of carboxypeptidases with a pivotal role in plant development and stress adaptation. Its most prominent mutant defect is a unique hypertrophic shoot phenotype combining a strongly increased organ formation rate with enhanced meristem size and the formation of ectopic meristem poles. However, so far the role of AMP1 in shoot development could not be assigned to a specific molecular pathway nor is its biochemical function resolved. In this work we evaluated the level of functional conservation between AMP1 and its human homolog HsGCPII, a tumor marker of medical interest. We show that HsGCPII cannot substitute AMP1 in planta and that an HsGCPII-specific inhibitor does not evoke amp1-specific phenotypes. We used a chemical genetic approach to identify the drug hyperphyllin (HP), which specifically mimics the shoot defects of amp1, including plastochron reduction and enlargement and multiplication of the shoot meristem. We assessed the structural requirements of HP activity and excluded that it is a cytokinin analog. HP-treated wild-type plants showed amp1-related tissue-specific changes of various marker genes and a significant transcriptomic overlap with the mutant. HP was ineffective in amp1 and elevated the protein levels of PHAVOLUTA, consistent with the postulated role of AMP1 in miRNA-controlled translation, further supporting an AMP1-related mode of action. Our work suggests that plant and animal members of the M28 family of proteases adopted unrelated functions. With HP we provide a tool to characterize the plant-specific functions of this important class of proteins.
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Affiliation(s)
- Olena Poretska
- Plant Growth Regulation, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (O.P., S.Y., T.S.); Department for Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria (O.P., D.P., K.Z., T.S.); Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (W.R., B.P.); Nottingham Arabidopsis Stock Centre, University of Nottingham, School of Biosciences, Sutton Bonington, LE12 5RD, UK (M.C.U., S.M.); and Cell and Systems Biology, University of Toronto, Toronto ON M5S 3B2, Canada (P.M.)
| | - Saiqi Yang
- Plant Growth Regulation, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (O.P., S.Y., T.S.); Department for Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria (O.P., D.P., K.Z., T.S.); Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (W.R., B.P.); Nottingham Arabidopsis Stock Centre, University of Nottingham, School of Biosciences, Sutton Bonington, LE12 5RD, UK (M.C.U., S.M.); and Cell and Systems Biology, University of Toronto, Toronto ON M5S 3B2, Canada (P.M.)
| | - Delphine Pitorre
- Plant Growth Regulation, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (O.P., S.Y., T.S.); Department for Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria (O.P., D.P., K.Z., T.S.); Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (W.R., B.P.); Nottingham Arabidopsis Stock Centre, University of Nottingham, School of Biosciences, Sutton Bonington, LE12 5RD, UK (M.C.U., S.M.); and Cell and Systems Biology, University of Toronto, Toronto ON M5S 3B2, Canada (P.M.)
| | - Wilfried Rozhon
- Plant Growth Regulation, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (O.P., S.Y., T.S.); Department for Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria (O.P., D.P., K.Z., T.S.); Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (W.R., B.P.); Nottingham Arabidopsis Stock Centre, University of Nottingham, School of Biosciences, Sutton Bonington, LE12 5RD, UK (M.C.U., S.M.); and Cell and Systems Biology, University of Toronto, Toronto ON M5S 3B2, Canada (P.M.)
| | - Karin Zwerger
- Plant Growth Regulation, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (O.P., S.Y., T.S.); Department for Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria (O.P., D.P., K.Z., T.S.); Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (W.R., B.P.); Nottingham Arabidopsis Stock Centre, University of Nottingham, School of Biosciences, Sutton Bonington, LE12 5RD, UK (M.C.U., S.M.); and Cell and Systems Biology, University of Toronto, Toronto ON M5S 3B2, Canada (P.M.)
| | - Marcos Castellanos Uribe
- Plant Growth Regulation, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (O.P., S.Y., T.S.); Department for Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria (O.P., D.P., K.Z., T.S.); Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (W.R., B.P.); Nottingham Arabidopsis Stock Centre, University of Nottingham, School of Biosciences, Sutton Bonington, LE12 5RD, UK (M.C.U., S.M.); and Cell and Systems Biology, University of Toronto, Toronto ON M5S 3B2, Canada (P.M.)
| | - Sean May
- Plant Growth Regulation, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (O.P., S.Y., T.S.); Department for Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria (O.P., D.P., K.Z., T.S.); Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (W.R., B.P.); Nottingham Arabidopsis Stock Centre, University of Nottingham, School of Biosciences, Sutton Bonington, LE12 5RD, UK (M.C.U., S.M.); and Cell and Systems Biology, University of Toronto, Toronto ON M5S 3B2, Canada (P.M.)
| | - Peter McCourt
- Plant Growth Regulation, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (O.P., S.Y., T.S.); Department for Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria (O.P., D.P., K.Z., T.S.); Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (W.R., B.P.); Nottingham Arabidopsis Stock Centre, University of Nottingham, School of Biosciences, Sutton Bonington, LE12 5RD, UK (M.C.U., S.M.); and Cell and Systems Biology, University of Toronto, Toronto ON M5S 3B2, Canada (P.M.)
| | - Brigitte Poppenberger
- Plant Growth Regulation, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (O.P., S.Y., T.S.); Department for Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria (O.P., D.P., K.Z., T.S.); Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (W.R., B.P.); Nottingham Arabidopsis Stock Centre, University of Nottingham, School of Biosciences, Sutton Bonington, LE12 5RD, UK (M.C.U., S.M.); and Cell and Systems Biology, University of Toronto, Toronto ON M5S 3B2, Canada (P.M.)
| | - Tobias Sieberer
- Plant Growth Regulation, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (O.P., S.Y., T.S.); Department for Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria (O.P., D.P., K.Z., T.S.); Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany (W.R., B.P.); Nottingham Arabidopsis Stock Centre, University of Nottingham, School of Biosciences, Sutton Bonington, LE12 5RD, UK (M.C.U., S.M.); and Cell and Systems Biology, University of Toronto, Toronto ON M5S 3B2, Canada (P.M.)
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Unterholzner SJ, Rozhon W, Poppenberger B. Reply: Interaction between Brassinosteroids and Gibberellins: Synthesis or Signaling? In Arabidopsis, Both! Plant Cell 2016. [PMID: 27006486 DOI: 10.1105/tpc.16.0012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Affiliation(s)
- Simon J Unterholzner
- Biotechnology of Horticultural CropsTUM School of Life Sciences WeihenstephanTechnische Universität MünchenD-85354 Freising, Germany
| | - Wilfried Rozhon
- Biotechnology of Horticultural CropsTUM School of Life Sciences WeihenstephanTechnische Universität MünchenD-85354 Freising, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural CropsTUM School of Life Sciences WeihenstephanTechnische Universität MünchenD-85354 Freising, Germany
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22
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Unterholzner SJ, Rozhon W, Poppenberger B. Reply: Interaction between Brassinosteroids and Gibberellins: Synthesis or Signaling? In Arabidopsis, Both! Plant Cell 2016; 28:836-9. [PMID: 27006486 PMCID: PMC4863389 DOI: 10.1105/tpc.16.00120] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 03/10/2016] [Accepted: 03/10/2016] [Indexed: 05/23/2023]
Affiliation(s)
- Simon J Unterholzner
- Biotechnology of Horticultural CropsTUM School of Life Sciences WeihenstephanTechnische Universität MünchenD-85354 Freising, Germany
| | - Wilfried Rozhon
- Biotechnology of Horticultural CropsTUM School of Life Sciences WeihenstephanTechnische Universität MünchenD-85354 Freising, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural CropsTUM School of Life Sciences WeihenstephanTechnische Universität MünchenD-85354 Freising, Germany
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23
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Eremina M, Rozhon W, Poppenberger B. Hormonal control of cold stress responses in plants. Cell Mol Life Sci 2016; 73:797-810. [PMID: 26598281 PMCID: PMC11108489 DOI: 10.1007/s00018-015-2089-6] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [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] [Received: 06/30/2015] [Revised: 10/20/2015] [Accepted: 11/05/2015] [Indexed: 10/22/2022]
Abstract
Cold stress responses in plants are highly sophisticated events that alter the biochemical composition of cells for protection from damage caused by low temperatures. In addition, cold stress has a profound impact on plant morphologies, causing growth repression and reduced yields. Complex signalling cascades are utilised to induce changes in cold-responsive gene expression that enable plants to withstand chilling or even freezing temperatures. These cascades are governed by the activity of plant hormones, and recent research has provided a better understanding of how cold stress responses are integrated with developmental pathways that modulate growth and initiate other events that increase cold tolerance. Information on the hormonal control of cold stress signalling is summarised to highlight the significant progress that has been made and indicate gaps that still exist in our understanding.
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Affiliation(s)
- Marina Eremina
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, 85354, Freising, Germany
| | - Wilfried Rozhon
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, 85354, Freising, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, 85354, Freising, Germany.
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24
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Unterholzner SJ, Rozhon W, Papacek M, Ciomas J, Lange T, Kugler KG, Mayer KF, Sieberer T, Poppenberger B. Brassinosteroids Are Master Regulators of Gibberellin Biosynthesis in Arabidopsis. Plant Cell 2015; 27:2261-72. [PMID: 26243314 PMCID: PMC4568508 DOI: 10.1105/tpc.15.00433] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 07/08/2015] [Accepted: 07/21/2015] [Indexed: 05/18/2023]
Abstract
Plant growth and development are highly regulated processes that are coordinated by hormones including the brassinosteroids (BRs), a group of steroids with structural similarity to steroid hormones of mammals. Although it is well understood how BRs are produced and how their signals are transduced, BR targets, which directly confer the hormone's growth-promoting effects, have remained largely elusive. Here, we show that BRs regulate the biosynthesis of gibberellins (GAs), another class of growth-promoting hormones, in Arabidopsis thaliana. We reveal that Arabidopsis mutants deficient in BR signaling are severely impaired in the production of bioactive GA, which is correlated with defective GA biosynthetic gene expression. Expression of the key GA biosynthesis gene GA20ox1 in the BR signaling mutant bri1-301 rescues many of its developmental defects. We provide evidence that supports a model in which the BR-regulated transcription factor BES1 binds to a regulatory element in promoters of GA biosynthesis genes in a BR-induced manner to control their expression. In summary, our study underscores a role of BRs as master regulators of GA biosynthesis and shows that this function is of major relevance for the growth and development of vascular plants.
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Affiliation(s)
- Simon J Unterholzner
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
| | - Wilfried Rozhon
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
| | - Michael Papacek
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
| | - Jennifer Ciomas
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
| | - Theo Lange
- Institute of Plant Biology, Technical University of Braunschweig, D-38106 Braunschweig, Germany
| | - Karl G Kugler
- Plant Genome and System Biology, Helmholtz Center Munich, D-85764 Neuherberg, Germany
| | - Klaus F Mayer
- Plant Genome and System Biology, Helmholtz Center Munich, D-85764 Neuherberg, Germany
| | - Tobias Sieberer
- Plant Growth Regulation, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
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25
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Liu CH, Finke A, Díaz M, Rozhon W, Poppenberger B, Baubec T, Pecinka A. Repair of DNA Damage Induced by the Cytidine Analog Zebularine Requires ATR and ATM in Arabidopsis. Plant Cell 2015; 27:1788-800. [PMID: 26023162 PMCID: PMC4498198 DOI: 10.1105/tpc.114.135467] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 05/11/2015] [Indexed: 05/04/2023]
Abstract
DNA damage repair is an essential cellular mechanism that maintains genome stability. Here, we show that the nonmethylable cytidine analog zebularine induces a DNA damage response in Arabidopsis thaliana, independent of changes in DNA methylation. In contrast to genotoxic agents that induce damage in a cell cycle stage-independent manner, zebularine induces damage specifically during strand synthesis in DNA replication. The signaling of this damage is mediated by additive activity of ATAXIA TELANGIECTASIA MUTATED AND RAD3-RELATED and ATAXIA TELANGIECTASIA MUTATED kinases, which cause postreplicative cell cycle arrest and increased endoreplication. The repair requires a functional STRUCTURAL MAINTENANCE OF CHROMOSOMES5 (SMC5)-SMC6 complex and is accomplished predominantly by synthesis-dependent strand-annealing homologous recombination. Here, we provide insight into the response mechanism for coping with the genotoxic effects of zebularine and identify several components of the zebularine-induced DNA damage repair pathway.
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Affiliation(s)
- Chun-Hsin Liu
- Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Andreas Finke
- Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Mariana Díaz
- Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Wilfried Rozhon
- Biotechnology of Horticultural Crops, Technische Universität München, 85354 Freising, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, Technische Universität München, 85354 Freising, Germany
| | | | - Ales Pecinka
- Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
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26
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Huang W, Pitorre D, Poretska O, Marizzi C, Winter N, Poppenberger B, Sieberer T. ALTERED MERISTEM PROGRAM1 suppresses ectopic stem cell niche formation in the shoot apical meristem in a largely cytokinin-independent manner. Plant Physiol 2015; 167:1471-86. [PMID: 25673776 PMCID: PMC4378165 DOI: 10.1104/pp.114.254623] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 02/09/2015] [Indexed: 05/03/2023]
Abstract
Plants are able to reiteratively form new organs in an environmentally adaptive manner during postembryonic development. Organ formation in plants is dependent on stem cell niches (SCNs), which are located in the so-called meristems. Meristems show a functional zonation along the apical-basal axis and the radial axis. Shoot apical meristems of higher plants are dome-like structures, which contain a central SCN that consists of an apical stem cell pool and an underlying organizing center. Organ primordia are formed in the circular peripheral zone (PZ) from stem cell descendants in which differentiation programs are activated. One mechanism to keep this radial symmetry integrated is that the existing SCN actively suppresses stem cell identity in the PZ. However, how this lateral inhibition system works at the molecular level is far from understood. Here, we show that a defect in the putative carboxypeptidase ALTERED MERISTEM PROGRAM1 (AMP1) causes the formation of extra SCNs in the presence of an intact primary shoot apical meristem, which at least partially contributes to the enhanced shoot meristem size and leaf initiation rate found in the mutant. This defect appears to be neither a specific consequence of the altered cytokinin levels in amp1 nor directly mediated by the WUSCHEL/CLAVATA feedback loop. De novo formation of supernumerary stem cell pools was further enhanced in plants mutated in both AMP1 and its paralog LIKE AMP1, indicating that they exhibit partially overlapping roles to suppress SCN respecification in the PZ.
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Affiliation(s)
- Wenwen Huang
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria (W.H., D.P., O.P., C.M., N.W., B.P., T.S.); andResearch Unit Plant Growth Regulation (O.P., T.S.) and Biotechnology of Horticultural Crops (B.P.), TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
| | - Delphine Pitorre
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria (W.H., D.P., O.P., C.M., N.W., B.P., T.S.); andResearch Unit Plant Growth Regulation (O.P., T.S.) and Biotechnology of Horticultural Crops (B.P.), TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
| | - Olena Poretska
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria (W.H., D.P., O.P., C.M., N.W., B.P., T.S.); andResearch Unit Plant Growth Regulation (O.P., T.S.) and Biotechnology of Horticultural Crops (B.P.), TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
| | - Christine Marizzi
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria (W.H., D.P., O.P., C.M., N.W., B.P., T.S.); andResearch Unit Plant Growth Regulation (O.P., T.S.) and Biotechnology of Horticultural Crops (B.P.), TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
| | - Nikola Winter
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria (W.H., D.P., O.P., C.M., N.W., B.P., T.S.); andResearch Unit Plant Growth Regulation (O.P., T.S.) and Biotechnology of Horticultural Crops (B.P.), TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
| | - Brigitte Poppenberger
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria (W.H., D.P., O.P., C.M., N.W., B.P., T.S.); andResearch Unit Plant Growth Regulation (O.P., T.S.) and Biotechnology of Horticultural Crops (B.P.), TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
| | - Tobias Sieberer
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria (W.H., D.P., O.P., C.M., N.W., B.P., T.S.); andResearch Unit Plant Growth Regulation (O.P., T.S.) and Biotechnology of Horticultural Crops (B.P.), TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
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27
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Eremina M, Rozhon W, Yang S, Poppenberger B. ENO2 activity is required for the development and reproductive success of plants, and is feedback-repressed by AtMBP-1. Plant J 2015; 81:895-906. [PMID: 25620024 DOI: 10.1111/tpj.12775] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 01/13/2015] [Accepted: 01/13/2015] [Indexed: 06/04/2023]
Abstract
Enolases are key glycolytic enzymes that are highly conserved in prokaryotic and eukaryotic organisms, and are among the most abundant cytosolic proteins. In this study we provide evidence that activity of the enolase ENO2 is essential for the growth and development of plants. We show that Arabidopsis plants with compromised ENO2 function, which were generated by mutating the LOS2/ENO2 locus, have severe cellular defects, including reduced cell size and defective cell differentiation with restricted lignification. At the tissue and organ level LOS2/ENO2-deficient plants are characterized by the reduced growth of shoots and roots, altered vascular development and defective secondary growth of stems, impaired floral organogenesis and defective male gametophyte function, resulting in embryo lethality as well as delayed senescence. These phenotypes correlate with reduced lignin and increased salicylic acid contents as well as altered fatty acid and soluble sugar composition. In addition to an enolase the LOS2/ENO2 locus encodes the transcription factor AtMBP-1, and here we reveal that this bifunctionality serves to maintain the homeostasis of ENO2 activity. In summary, we show that in plants enolase function is required for the formation of chorismate-dependent secondary metabolites, and that this activity is feedback-inhibited by AtMBP-1 to enable the normal development and reproductive success of plants.
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Affiliation(s)
- Marina Eremina
- Biotechnology of Horticultural Crops, Center for Life and Food Sciences Weihenstephan, Technische Universität München, D-85354, Freising, Germany
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28
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Petutschnig EK, Stolze M, Lipka U, Kopischke M, Horlacher J, Valerius O, Rozhon W, Gust AA, Kemmerling B, Poppenberger B, Braus GH, Nürnberger T, Lipka V. A novel Arabidopsis CHITIN ELICITOR RECEPTOR KINASE 1 (CERK1) mutant with enhanced pathogen-induced cell death and altered receptor processing. New Phytol 2014; 204:955-67. [PMID: 25041086 DOI: 10.1111/nph.12920] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 06/02/2014] [Indexed: 05/23/2023]
Abstract
Plants detect pathogens by sensing microbe-associated molecular patterns (MAMPs) through pattern recognition receptors. Pattern recognition receptor complexes also have roles in cell death control, but the underlying mechanisms are poorly understood. Here, we report isolation of cerk1-4, a novel mutant allele of the Arabidopsis chitin receptor CERK1 with enhanced defense responses. We identified cerk1-4 in a forward genetic screen with barley powdery mildew and consequently characterized it by pathogen assays, mutant crosses and analysis of defense pathways. CERK1 and CERK1-4 proteins were analyzed biochemically. The cerk1-4 mutation causes an amino acid exchange in the CERK1 ectodomain. Mutant plants maintain chitin signaling capacity but exhibit hyper-inducible salicylic acid concentrations and deregulated cell death upon pathogen challenge. In contrast to chitin signaling, the cerk1-4 phenotype does not require kinase activity and is conferred by the N-terminal part of the receptor. CERK1 undergoes ectodomain shedding, a well-known process in animal cell surface proteins. Wild-type plants contain the full-length CERK1 receptor protein as well as a soluble form of the CERK1 ectodomain, whereas cerk1-4 plants lack the N-terminal shedding product. Our work suggests that CERK1 may have a chitin-independent role in cell death control and is the first report of ectodomain shedding in plants.
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Affiliation(s)
- Elena K Petutschnig
- Department of Plant Cell Biology, Albrecht von Haller Institute, Georg August University Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany; The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
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29
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Khan M, Rozhon W, Unterholzner SJ, Chen T, Eremina M, Wurzinger B, Bachmair A, Teige M, Sieberer T, Isono E, Poppenberger B. Interplay between phosphorylation and SUMOylation events determines CESTA protein fate in brassinosteroid signalling. Nat Commun 2014; 5:4687. [PMID: 25134617 PMCID: PMC4167607 DOI: 10.1038/ncomms5687] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [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: 01/15/2014] [Accepted: 07/14/2014] [Indexed: 02/05/2023] Open
Abstract
Brassinosteroids are steroid hormones that are essential for plant growth. Responses to these hormones are mediated by transcription factors of the BES1/BZR1 subfamily, and brassinosteroids activate these factors by impairing their inhibitory phosphorylation by GSK3/shaggy-like kinases. Here we show that brassinosteroids induce nuclear compartmentalization of CESTA (CES), a bHLH transcription factor that regulates brassinosteroid responses, and reveal that this process is regulated by CES SUMOylation. We demonstrate that CES contains an extended SUMOylation motif, and that SUMOylation of this motif is antagonized by phosphorylation to control CES subnuclear localization. Moreover, we provide evidence that phosphorylation regulates CES transcriptional activity and protein turnover by the proteasome. A coordinated modification model is proposed in which, in a brassinosteroid-deficient situation, CES is phosphorylated to activate target gene transcription and enable further posttranslational modification that controls CES protein stability.
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Affiliation(s)
- Mamoona Khan
- 1] Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany [2] Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
| | - Wilfried Rozhon
- 1] Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany [2] Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
| | - Simon Josef Unterholzner
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
| | - Tingting Chen
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
| | - Marina Eremina
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
| | - Bernhard Wurzinger
- Department of Molecular Systems Biology, University of Vienna, A-1090 Vienna, Austria
| | - Andreas Bachmair
- Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
| | - Markus Teige
- Department of Molecular Systems Biology, University of Vienna, A-1090 Vienna, Austria
| | - Tobias Sieberer
- Plant Growth Regulation, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
| | - Erika Isono
- Plant Systems Biology, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany
| | - Brigitte Poppenberger
- 1] Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany [2] Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
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Rozhon W, Wang W, Berthiller F, Mayerhofer J, Chen T, Petutschnig E, Sieberer T, Poppenberger B, Jonak C. Bikinin-like inhibitors targeting GSK3/Shaggy-like kinases: characterisation of novel compounds and elucidation of their catabolism in planta. BMC Plant Biol 2014; 14:172. [PMID: 24947596 PMCID: PMC4078015 DOI: 10.1186/1471-2229-14-172] [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] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 06/17/2014] [Indexed: 05/08/2023]
Abstract
BACKGROUND Plant GSK-3/Shaggy-like kinases are key players in brassinosteroid (BR) signalling which impact on plant development and participate in response to wounding, pathogens and salt stress. Bikinin was previously identified in a chemical genetics screen as an inhibitor targeting these kinases. To dissect the structural elements crucial for inhibition of GSK-3/Shaggy-like kinases by bikinin and to isolate more potent compounds we synthesised a number of related substances and tested their inhibitory activity in vitro and in vivo using Arabidopsis thaliana. RESULTS A pyridine ring with an amido succinic acid residue in position 2 and a halogen in position 5 were crucial for inhibitory activity. The compound with an iodine substituent in position 5, denoted iodobikinin, was most active in inhibiting BIN2 activity in vitro and efficiently induced brassinosteroid-like responses in vivo. Its methyl ester, methyliodobikinin, showed improved cell permeability, making it highly potent in vivo although it had lower activity in vitro. HPLC analysis revealed that the methyl residue was rapidly cleaved off in planta liberating active iodobikinin. In addition, we provide evidence that iodobikinin and bikinin are inactivated in planta by conjugation with glutamic acid or malic acid and that the latter process is catalysed by the malate transferase SNG1. CONCLUSION Brassinosteroids participate in regulation of many aspects of plant development and in responses to environmental cues. Thus compounds modulating their action are valuable tools to study such processes and may be an interesting opportunity to modify plant growth and performance in horticulture and agronomy. Here we report the development of bikinin derivatives with increased potency that can activate BR signalling and mimic BR action. Methyliodobikinin was 3.4 times more active in vivo than bikinin. The main reason for the superior activity of methyliodobikinin, the most potent compound, is its enhanced plant tissue permeability. Inactivation of bikinin and its derivatives in planta involves SNG1, which constitutes a novel pathway for modification of xenobiotic compounds.
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Affiliation(s)
- Wilfried Rozhon
- GMI-Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna Biocenter, Dr. Bohr-Gasse 3, Vienna 1030, Austria
- Biotechnology of Horticultural Crops, Technische Universität München, Liesel-Beckmann-Straße 1, Freising 85354, Germany
- Max F. Perutz Laboratories, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna 1030, Austria
| | - Wuyan Wang
- Biotechnology of Horticultural Crops, Technische Universität München, Liesel-Beckmann-Straße 1, Freising 85354, Germany
- Present address: Plant Biochemistry, ETH Zürich, Universitätsstr. 2, Zürich 8092, Switzerland
| | - Franz Berthiller
- Center for Analytical Chemistry, Department of Agrobiotechnology, University of Natural Resources and Life Sciences, Konrad Lorenz Straße 20, Tulln 3430, Austria
| | - Juliane Mayerhofer
- GMI-Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna Biocenter, Dr. Bohr-Gasse 3, Vienna 1030, Austria
| | - Tingting Chen
- Biotechnology of Horticultural Crops, Technische Universität München, Liesel-Beckmann-Straße 1, Freising 85354, Germany
| | - Elena Petutschnig
- GMI-Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna Biocenter, Dr. Bohr-Gasse 3, Vienna 1030, Austria
- Present address: Albrecht-von-Haller-Institute of Plant Sciences, Department of Plant Cell Biology, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, Göttingen 37077, Germany
| | - Tobias Sieberer
- Max F. Perutz Laboratories, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna 1030, Austria
- Department of Plant Sciences, Research Unit Plant Growth Regulation, Technische Universität München, Liesel-Beckmann-Straße 1, Freising-Weihenstephan 85354, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, Technische Universität München, Liesel-Beckmann-Straße 1, Freising 85354, Germany
- Max F. Perutz Laboratories, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna 1030, Austria
| | - Claudia Jonak
- GMI-Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna Biocenter, Dr. Bohr-Gasse 3, Vienna 1030, Austria
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Khan M, Rozhon W, Poppenberger B. The Role of Hormones in the Aging of Plants - A Mini-Review. Gerontology 2014; 60:49-55. [DOI: 10.1159/000354334] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 07/09/2013] [Indexed: 11/19/2022] Open
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Unterholzner SJ, Hailer B, Poppenberger B, Rozhon W. Characterisation of the stbD/E toxin-antitoxin system of pEP36, a plasmid of the plant pathogen Erwinia pyrifoliae. Plasmid 2013; 70:216-25. [PMID: 23632277 DOI: 10.1016/j.plasmid.2013.04.002] [Citation(s) in RCA: 15] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 04/15/2013] [Accepted: 04/17/2013] [Indexed: 11/29/2022]
Abstract
pEP36 is a plasmid ubiquitously present in Erwinia pyrifoliae, a pathogen which causes black stem blight of Asian pear. pEP36 is highly stable in its host, even in the absence of selective pressure. The plasmid is closely related to pEA29, which is widespread in E. amylovora, the causative agent of fire blight of apple and pear trees. Here we report that pEP36 possesses a functional hybrid toxin-antitoxin module, stbD/E(pEP36), with the toxin showing homology to the RelE/ParE proteins and the antidote belonging to the Phd/YefM antitoxin family. Bacteria expressing the StbE(pEP36) toxin arrest cell growth and enter a viable but non-culturable stage. However, they maintain their typical cell length and do not show filamentation. Pulse-chase experiments revealed that StbE(pEP36) acts as a global inhibitor of protein synthesis while it does not interfere with DNA and RNA synthesis. The StbD(pEP36) antitoxin is capable of neutralising StbE(pEP36) toxicity. Additional experiments show that the stbD/E(pEP36) module can stabilise plasmids at least 20-fold. Thus the toxin-antitoxin system may contribute to the remarkable stability of pEP36.
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Affiliation(s)
- Simon J Unterholzner
- Biotechnology of Horticultural Crops, Technische Universität München, Liesel-Beckmann-Straße 1, 85354 Freising, Germany.
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Unterholzner SJ, Poppenberger B, Rozhon W. Toxin-antitoxin systems: Biology, identification, and application. Mob Genet Elements 2013; 3:e26219. [PMID: 24251069 PMCID: PMC3827094 DOI: 10.4161/mge.26219] [Citation(s) in RCA: 223] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 08/16/2013] [Accepted: 08/19/2013] [Indexed: 02/07/2023] Open
Abstract
Toxin–antitoxin (TA) systems are small genetic elements composed of a toxin gene and its cognate antitoxin. The toxins of all known TA systems are proteins while the antitoxins are either proteins or non-coding RNAs. Based on the molecular nature of the antitoxin and its mode of interaction with the toxin the TA modules are currently grouped into five classes. In general, the toxin is more stable than the antitoxin but the latter is expressed to a higher level. If supply of the antitoxin stops, for instance under special growth conditions or by plasmid loss in case of plasmid encoded TA systems, the antitoxin is rapidly degraded and can no longer counteract the toxin. Consequently, the toxin becomes activated and can act on its cellular targets. Typically, TA toxins act on crucial cellular processes including translation, replication, cytoskeleton formation, membrane integrity, and cell wall biosynthesis. TA systems and their components are also versatile tools for a multitude of purposes in basic research and biotechnology. Currently, TA systems are frequently used for selection in cloning and for single protein expression in living bacterial cells. Since several TA toxins exhibit activity in yeast and mammalian cells they may be useful for applications in eukaryotic systems. TA modules are also considered as promising targets for the development of antibacterial drugs and their potential to combat viral infection may aid in controlling infectious diseases.
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Affiliation(s)
- Simon J Unterholzner
- 1 Biotechnology of Horticultural Crops; Technische Universität München; Freising, Germany
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Khan M, Rozhon W, Bigeard J, Pflieger D, Husar S, Pitzschke A, Teige M, Jonak C, Hirt H, Poppenberger B. Brassinosteroid-regulated GSK3/Shaggy-like kinases phosphorylate mitogen-activated protein (MAP) kinase kinases, which control stomata development in Arabidopsis thaliana. J Biol Chem 2013; 288:7519-7527. [PMID: 23341468 DOI: 10.1074/jbc.m112.384453] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Brassinosteroids (BRs) are steroid hormones that coordinate fundamental developmental programs in plants. In this study we show that in addition to the well established roles of BRs in regulating cell elongation and cell division events, BRs also govern cell fate decisions during stomata development in Arabidopsis thaliana. In wild-type A. thaliana, stomatal distribution follows the one-cell spacing rule; that is, adjacent stomata are spaced by at least one intervening pavement cell. This rule is interrupted in BR-deficient and BR signaling-deficient A. thaliana mutants, resulting in clustered stomata. We demonstrate that BIN2 and its homologues, GSK3/Shaggy-like kinases involved in BR signaling, can phosphorylate the MAPK kinases MKK4 and MKK5, which are members of the MAPK module YODA-MKK4/5-MPK3/6 that controls stomata development and patterning. BIN2 phosphorylates a GSK3/Shaggy-like kinase recognition motif in MKK4, which reduces MKK4 activity against its substrate MPK6 in vitro. In vivo we show that MKK4 and MKK5 act downstream of BR signaling because their overexpression rescued stomata patterning defects in BR-deficient plants. A model is proposed in which GSK3-mediated phosphorylation of MKK4 and MKK5 enables for a dynamic integration of endogenous or environmental cues signaled by BRs into cell fate decisions governed by the YODA-MKK4/5-MPK3/6 module.
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Affiliation(s)
- Mamoona Khan
- Institute Biotechnology of Horticultural Crops, Center for Life and Food Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany; Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
| | - Wilfried Rozhon
- Institute Biotechnology of Horticultural Crops, Center for Life and Food Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany; Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
| | - Jean Bigeard
- Unité de Recherche en Génomique Végétale Plant Genomics 2, rue Gaston Cremieux, 91057 Evry, France
| | - Delphine Pflieger
- Laboratoire Analyse et Modélisation pour la Biologie et l'Environnement, CNRS, University of Evry, Boulevard François Mitterrand, 91025 Evry, France
| | - Sigrid Husar
- Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
| | - Andrea Pitzschke
- Department for Applied Genetics and Cell Biology, University of Natural Resources and Applied Life Sciences, A-1190 Vienna, Austria
| | - Markus Teige
- Department of Molecular Systems Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Claudia Jonak
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, A-1030 Vienna, Austria
| | - Heribert Hirt
- Unité de Recherche en Génomique Végétale Plant Genomics 2, rue Gaston Cremieux, 91057 Evry, France; College of Science, King Saud University, P. O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Brigitte Poppenberger
- Institute Biotechnology of Horticultural Crops, Center for Life and Food Sciences Weihenstephan, Technische Universität München, D-85354 Freising, Germany; Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria.
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Rozhon W, Khan M, Poppenberger B. Identification of the region required for maintaining pHW126 in its monomeric form. FEMS Microbiol Lett 2012; 331:89-96. [PMID: 22448845 DOI: 10.1111/j.1574-6968.2012.02557.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 03/22/2012] [Indexed: 11/29/2022] Open
Abstract
The pHW126-like plasmids are a recently discovered small group of cryptic plasmids replicating by the rolling circle mode. The replication origin of pHW126 consists of a conserved stretch, four perfect direct repeats and a so-called accessory region. The latter increases plasmid stability but is not absolutely necessary for replication. Here, we report that deletion of the accessory region causes rapid multimerization of pHW126. While the number of pHW126-units per cell remains constant, the number of physically independent plasmid molecules is reduced by approximately 40%, rendering random distribution to daughter cells less effective. A conserved inverted repeat within the accessory region could be identified as a sequence necessary for maintaining pHW126 in its monomeric form. A mutant version of pHW126 lacking this inverted repeat could be rescued by placing the single-strand initiation site (ssi) of pHW15 on the plus strand, while including the ssi in the opposite direction had no effect. Thus, our data provide evidence that multimer formation is, besides copy number reduction and ssDNA accumulation, an additional means how loss of a mechanism ensuring efficient lagging strand synthesis may cause destabilization of rolling circle plasmids.
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Affiliation(s)
- Wilfried Rozhon
- Biotechnology of Horticultural Crops, Technische Universität München, Freising, Germany.
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Husar S, Berthiller F, Fujioka S, Rozhon W, Khan M, Kalaivanan F, Elias L, Higgins GS, Li Y, Schuhmacher R, Krska R, Seto H, Vaistij FE, Bowles D, Poppenberger B. Overexpression of the UGT73C6 alters brassinosteroid glucoside formation in Arabidopsis thaliana. BMC Plant Biol 2011; 11:51. [PMID: 21429230 PMCID: PMC3073898 DOI: 10.1186/1471-2229-11-51] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [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: 11/25/2010] [Accepted: 03/24/2011] [Indexed: 05/18/2023]
Abstract
BACKGROUND Brassinosteroids (BRs) are signaling molecules that play essential roles in the spatial regulation of plant growth and development. In contrast to other plant hormones BRs act locally, close to the sites of their synthesis, and thus homeostatic mechanisms must operate at the cellular level to equilibrate BR concentrations. Whilst it is recognized that levels of bioactive BRs are likely adjusted by controlling the relative rates of biosynthesis and by catabolism, few factors, which participate in these regulatory events, have as yet been identified. Previously we have shown that the UDP-glycosyltransferase UGT73C5 of Arabidopsis thaliana catalyzes 23-O-glucosylation of BRs and that glucosylation renders BRs inactive. This study identifies the closest homologue of UGT73C5, UGT73C6, as an enzyme that is also able to glucosylate BRs in planta. RESULTS In a candidate gene approach, in which homologues of UGT73C5 were screened for their potential to induce BR deficiency when over-expressed in plants, UGT73C6 was identified as an enzyme that can glucosylate the BRs CS and BL at their 23-O-positions in planta. GUS reporter analysis indicates that UGT73C6 shows over-lapping, but also distinct expression patterns with UGT73C5 and YFP reporter data suggests that at the cellular level, both UGTs localize to the cytoplasm and to the nucleus. A liquid chromatography high-resolution mass spectrometry method for BR metabolite analysis was developed and applied to determine the kinetics of formation and the catabolic fate of BR-23-O-glucosides in wild type and UGT73C5 and UGT73C6 over-expression lines. This approach identified novel BR catabolites, which are considered to be BR-malonylglucosides, and provided first evidence indicating that glucosylation protects BRs from cellular removal. The physiological significance of BR glucosylation, and the possible role of UGT73C6 as a regulatory factor in this process are discussed in light of the results presented. CONCLUSION The present study generates essential knowledge and molecular and biochemical tools, that will allow for the verification of a potential physiological role of UGT73C6 in BR glucosylation and will facilitate the investigation of the functional significance of BR glucoside formation in plants.
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Affiliation(s)
- Sigrid Husar
- Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Franz Berthiller
- Center for Analytical Chemistry, Department of Agrobiotechnology, University of Natural Resources and Life Sciences, Konrad Lorenz Straße 20, 3430 Tulln, Austria
| | - Shozo Fujioka
- RIKEN Advanced Science Institute, Wako-shi, Saitama 351-0198, Japan
| | - Wilfried Rozhon
- Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Mamoona Khan
- Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Florian Kalaivanan
- Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Luisa Elias
- Center for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, UK
| | - Gillian S Higgins
- Center for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, UK
| | - Yi Li
- Center for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, UK
| | - Rainer Schuhmacher
- Center for Analytical Chemistry, Department of Agrobiotechnology, University of Natural Resources and Life Sciences, Konrad Lorenz Straße 20, 3430 Tulln, Austria
| | - Rudolf Krska
- Center for Analytical Chemistry, Department of Agrobiotechnology, University of Natural Resources and Life Sciences, Konrad Lorenz Straße 20, 3430 Tulln, Austria
| | - Hideharu Seto
- RIKEN Advanced Science Institute, Wako-shi, Saitama 351-0198, Japan
| | - Fabian E Vaistij
- Center for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, UK
| | - Dianna Bowles
- Center for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, UK
| | - Brigitte Poppenberger
- Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
- Center for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, UK
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Rozhon W, Khan M, Petutschnig E, Poppenberger B. Identification of cis- and trans-acting elements in pHW126, a representative of a novel group of rolling circle plasmids. Plasmid 2010; 65:70-6. [PMID: 20854841 DOI: 10.1016/j.plasmid.2010.09.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 09/13/2010] [Accepted: 09/14/2010] [Indexed: 10/19/2022]
Abstract
pHW126, pIGRK, pIGMS31 and pRAO1 are the only known members of a novel and as yet uncharacterised family of rolling circle plasmids. pHW126 contains only two open reading frames, of which one shows homology to pMV158-family mobilisation proteins. Here we provide evidence that the second open reading frame encodes a replication protein (Rep). Mutation or deletion of this gene resulted in replication deficient constructs, but providing functional Rep from a compatible vector rescued these constructs, indicating that Rep acts in trans. An approximately 300 bp cis-acting region representing the origin of replication was identified upstream of the rep gene. The origin was identified to be composed of three parts: an accessory region, a conserved stretch and four perfect tandem repeats. The two latter elements were essential for replication. Constructs with a deletion of the accessory region could still replicate, but their loss rate was high, indicating that the accessory region is necessary for plasmid maintenance under non-selective conditions. Interestingly, pHW126 could replicate in all Enterobacteriaceae tested while Agrobacterium tumefaciens and Pseudomonas syringae were inappropriate hosts. Thus, pHW126 seems to have a rather limited host range.
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Affiliation(s)
- Wilfried Rozhon
- Max F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9, 1030 Vienna, Austria.
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Schweiger W, Boddu J, Shin S, Poppenberger B, Berthiller F, Lemmens M, Muehlbauer GJ, Adam G. Validation of a candidate deoxynivalenol-inactivating UDP-glucosyltransferase from barley by heterologous expression in yeast. Mol Plant Microbe Interact 2010; 23:977-86. [PMID: 20521959 DOI: 10.1094/mpmi-23-7-0977] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Resistance to the virulence factor deoxynivalenol (DON) due to formation of DON-3-O-glucoside (D3G) is considered to be an important component of resistance against Fusarium spp. which produce this toxin. Multiple candidate UDP-glycosyltransferase (UGT) genes from different crop plants that are either induced by Fusarium spp. or differentially expressed in cultivars varying in Fusarium disease resistance have been described. However, UGT are encoded by a very large gene family in plants. The study of candidate plant UGT is highly warranted because of the potential relevance for developing Fusarium-spp.-resistant crops. We tested Arabidopsis thaliana genes closely related to a previously identified DON-glucosyltransferase gene by heterologous expression in yeast and showed that gene products with very high sequence similarity can have pronounced differences in detoxification capabilities. We also tested four candidate barley glucosyltransferases, which are highly DON inducible. Upon heterologous expression of full-length cDNAs, only one gene, HvUGT13248, conferred DON resistance. The conjugate D3G accumulated in the supernatant of DON-treated yeast transformants. We also present evidence that the product of the TaUGT3 gene recently proposed to encode a DON-detoxification enzyme of wheat does not protect yeast against DON.
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Affiliation(s)
- Wolfgang Schweiger
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Applied Life Sciences, Vienna, Austria
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Rozhon W, Petutschnig E, Khan M, Summers DK, Poppenberger B. Frequency and diversity of small cryptic plasmids in the genus Rahnella. BMC Microbiol 2010; 10:56. [PMID: 20170524 PMCID: PMC2831885 DOI: 10.1186/1471-2180-10-56] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [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: 07/17/2009] [Accepted: 02/19/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rahnella is a widely distributed genus belonging to the Enterobacteriaceae and frequently present on vegetables. Although Rahnella has interesting agro-economical and industrial properties and several strains possess antibiotic resistances and toxin genes which might spread within microbial communities, little is known about plasmids of this genus. Thus, we isolated a number of Rahnella strains and investigated their complements of small plasmids. RESULTS In total 53 strains were investigated and 11 plasmids observed. Seven belonged to the ColE1 family; one was ColE2-like and three shared homology to rolling circle plasmids. One of them belonged to the pC194/pUB110 family and two showed similarity to poorly characterised plasmid groups. The G+C content of two rolling circle plasmids deviated considerably from that of Rahnella, indicating that their usual hosts might belong to other genera. Most ColE1-like plasmids formed a subgroup within the ColE1 family that seems to be fairly specific for Rahnella. Intriguingly, the multimer resolution sites of all ColE1-like plasmids had the same orientation with respect to the origin of replication. This arrangement might be necessary to prevent inappropriate synthesis of a small regulatory RNA that regulates cell division. Although the ColE1-like plasmids did not possess any mobilisation system, they shared large parts with high sequence identity in coding and non-coding regions. In addition, highly homologous regions of plasmids isolated from Rahnella and the chromosomes of Erwinia tasmaniensis and Photorhabdus luminescens could be identified. CONCLUSIONS For the genus Rahnella we observed plasmid-containing isolates at a frequency of 19%, which is in the average range for Enterobacteriaceae. These plasmids belonged to different groups with members of the ColE1-family most frequently found. Regions of striking sequence homology of plasmids and bacterial chromosomes highlight the importance of plasmids for lateral gene transfer (including chromosomal sequences) to distinct genera.
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Affiliation(s)
- Wilfried Rozhon
- Max F Perutz Laboratories, University of Vienna, Dr Bohrgasse 9, Vienna, Austria.
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Poppenberger B, Berthiller F, Bachmann H, Lucyshyn D, Peterbauer C, Mitterbauer R, Schuhmacher R, Krska R, Glössl J, Adam G. Heterologous expression of Arabidopsis UDP-glucosyltransferases in Saccharomyces cerevisiae for production of zearalenone-4-O-glucoside. Appl Environ Microbiol 2006; 72:4404-10. [PMID: 16751557 PMCID: PMC1489669 DOI: 10.1128/aem.02544-05] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2005] [Accepted: 04/04/2006] [Indexed: 02/01/2023] Open
Abstract
Zearalenone, a secondary metabolite produced by several plant-pathogenic fungi of the genus Fusarium, has high estrogenic activity in vertebrates. We developed a Saccharomyces cerevisiae bioassay strain that we used to identify plant genes encoding UDP-glucosyltransferases that can convert zearalenone into zearalenone-4-O-glucoside (ZON-4-O-Glc). Attachment of the glucose moiety to zearalenone prevented the interaction of the mycotoxin with the human estrogen receptor. We found that two of six clustered, similar UGT73C genes of Arabidopsis thaliana encode glucosyltransferases that can inactivate zearalenone in the yeast bioassay. The formation of glucose conjugates seems to be an important plant mechanism for coping with zearalenone but may result in significant amounts of "masked" zearalenone in Fusarium-infected plant products. Due to the unavailability of an analytical standard, the ZON-4-O-Glc is not measured in routine analytical procedures, even though it can be converted back to active zearalenone in the digestive tracts of animals. Zearalenone added to yeast transformed with UGT73C6 was converted rapidly and efficiently to ZON-4-O-Glc, suggesting that the cloned UDP-glucosyltransferase could be used to produce reference glucosides of zearalenone and its derivatives.
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Affiliation(s)
- Brigitte Poppenberger
- Institute of Applied Genetics and Cell Biology, Department of Applied Plant Sciences and Plant Biotechnology, BOKU-University of Natural Resources and Applied Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
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Abstract
Glycosyltransferases of small molecules transfer sugars to a wide range of acceptors, from hormones and secondary metabolites to biotic and abiotic chemicals and toxins in the environment. The enzymes are encoded by large multigene families and can be identified by a signature motif in their primary sequence, which classifies them as a subset of Family 1 glycosyltransferases. The transfer of a sugar onto a lipophilic acceptor changes its chemical properties, alters its bioactivity, and enables access to membrane transporter systems. In vitro studies have shown that a single gene product can glycosylate multiple substrates of diverse origins; multiple enzymes can also glycosylate the same substrate. These features suggest that in a cellular context, substrate availability is a determining factor in enzyme function, and redundancy depends on the extent of coordinate gene regulation. This review discusses the role of these glycosyltransferases in underpinning developmental and metabolic plasticity during adaptive responses.
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Affiliation(s)
- Dianna Bowles
- Center for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, United Kingdom.
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Poppenberger B, Fujioka S, Soeno K, George GL, Vaistij FE, Hiranuma S, Seto H, Takatsuto S, Adam G, Yoshida S, Bowles D. The UGT73C5 of Arabidopsis thaliana glucosylates brassinosteroids. Proc Natl Acad Sci U S A 2005; 102:15253-8. [PMID: 16214889 PMCID: PMC1257699 DOI: 10.1073/pnas.0504279102] [Citation(s) in RCA: 162] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Steroid hormones are essential for development, and the precise control of their homeostasis is a prerequisite for normal growth. UDP-glycosyltransferases (UGTs) are considered to play an important regulatory role in the activity of steroids in mammals and insects. This study provides an indication that a UGT accepting plant steroids as substrates functions in brassinosteroid (BR) homeostasis. The UGT73C5 of Arabidopsis thaliana catalyses 23-O-glucosylation of the BRs brassinolide (BL) and castasterone. Transgenic plants overexpressing UGT73C5 displayed BR-deficient phenotypes and contained reduced amounts of BRs. The phenotype, which was already apparent in seedlings, could be rescued by application of BR. In feeding experiments with BL, wild-type seedlings converted BL to the 23-O-glucoside; in the transgenic lines silenced in UGT73C5 expression, no 23-O-glucoside was detected, implying that this UGT is the only enzyme that catalyzes BL-23-O-glucosylation in seedlings. Plant lines in which UGT73C5 expression was altered also displayed hypocotyl phenotypes previously described for seedlings in which BR inactivation by hydroxylation was changed. These data support the hypothesis that 23-O-glucosylation of BL is a function of UGT73C5 in planta, and that glucosylation regulates BR activity.
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Affiliation(s)
- Brigitte Poppenberger
- Center for Novel Agricultural Products, Department of Biology, University of York, YO10 5DD, York, United Kingdom
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Abstract
Studies of the glycosyltransferases (GTs) of small molecules have greatly increased in recent years as new approaches have been used to identify their genes and characterize their catalytic activities. These enzymes recognize diverse acceptors, including plant metabolites, phytotoxins and xenobiotics. Glycosylation alters the hydrophilicity of the acceptors, their stability and chemical properties, their subcellular localisation and often their bioactivity. Considerable progress has been made in understanding the role of GTs in the plant and the utility of GTs as biocatalysts, the latter arising from their regio- and enantioselectivity and their ability to recognize substrates that are not limited to plant metabolites.
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Affiliation(s)
- Dianna Bowles
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, York YO10 5DD, UK.
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Mitterbauer R, Poppenberger B, Raditschnig A, Lucyshyn D, Lemmens M, Glössl J, Adam G. Toxin-dependent utilization of engineered ribosomal protein L3 limits trichothecene resistance in transgenic plants. Plant Biotechnol J 2004; 2:329-40. [PMID: 17134394 DOI: 10.1111/j.1467-7652.2004.00075.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The contamination of agricultural products with Fusarium mycotoxins is a problem of world-wide importance. Fusarium graminearum and related species, which are important pathogens of small grain cereals and maize, produce an economically important and structurally diverse class of toxins designated trichothecenes. Trichothecenes inhibit eukaryotic protein synthesis. Therefore, a proposed role for these fungal toxins in plant disease development is to block or delay the expression of defence-related proteins induced by the plant. Using yeast as a model system, we have identified several mutations in the gene encoding ribosomal protein L3 (Rpl3), which confer semi-dominant resistance to trichothecenes. Expression of an engineered tomato RPL3 (LeRPL3) cDNA, into which one of the amino acid changes identified in yeast was introduced, improved the ability of transgenic tobacco plants to adapt to the trichothecene deoxynivalenol (DON), but did not result in constitutive resistance. We show here that, in the presence of wild-type Rpl3 protein, the engineered Rpl3 protein is not utilized, unless yeast transformants or the transgenic plants are challenged with sublethal amounts of toxin. Our data from yeast two-hybrid experiments suggest that affinity for the ribosome assembly factor Rrb1p could be altered by the toxin resistance-conferring mutation. This toxin-dependent utilization of the resistance-conferring Rpl3 protein could seriously limit efforts to utilize the identified target alterations in transgenic crops to increase trichothecene tolerance and Fusarium resistance.
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Affiliation(s)
- Rudolf Mitterbauer
- Institute of Applied Genetics and Cell Biology, Department of Applied Plant Sciences and Plant Biotechnology, BOKU-University of Natural Resources and Applied Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
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Poppenberger B, Berthiller F, Lucyshyn D, Sieberer T, Schuhmacher R, Krska R, Kuchler K, Glössl J, Luschnig C, Adam G. Detoxification of the Fusarium mycotoxin deoxynivalenol by a UDP-glucosyltransferase from Arabidopsis thaliana. J Biol Chem 2003; 278:47905-14. [PMID: 12970342 DOI: 10.1074/jbc.m307552200] [Citation(s) in RCA: 367] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Plant pathogenic fungi of the genus Fusarium cause agriculturally important diseases of small grain cereals and maize. Trichothecenes are a class of mycotoxins produced by different Fusarium species that inhibit eukaryotic protein biosynthesis and presumably interfere with the expression of genes induced during the defense response of the plants. One of its members, deoxynivalenol, most likely acts as a virulence factor during fungal pathogenesis and frequently accumulates in grain to levels posing a threat to human and animal health. We report the isolation and characterization of a gene from Arabidopsis thaliana encoding a UDP-glycosyltransferase that is able to detoxify deoxynivalenol. The enzyme, previously assigned the identifier UGT73C5, catalyzes the transfer of glucose from UDP-glucose to the hydroxyl group at carbon 3 of deoxynivalenol. Using a wheat germ extract-coupled transcription/translation system we have shown that this enzymatic reaction inactivates the mycotoxin. This deoxynivalenol-glucosyltransferase (DOGT1) was also found to detoxify the acetylated derivative 15-acetyl-deoxynivalenol, whereas no protective activity was observed against the structurally similar nivalenol. Expression of the glucosyltransferase is developmentally regulated and induced by deoxynivalenol as well as salicylic acid, ethylene, and jasmonic acid. Constitutive overexpression in Arabidopsis leads to enhanced tolerance against deoxynivalenol.
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Affiliation(s)
- Brigitte Poppenberger
- Center of Applied Genetics, BOKU - University of Natural Resources and Applied Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
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Mitterbauer R, Bachmann H, Poppenberger B, Safaie N, Adam G. Development and applications of a yeast-based bioassay for the mycotoxin zearalenone. Mycotoxin Res 2003; 19:69-72. [PMID: 23604673 DOI: 10.1007/bf02940097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Zearalenone (ZON) is a non-steroidal estrogenic mycotoxin produced by plant pathogenic species ofFusarium. As a consequence of infection withF. culmorum andF. graminearum, ZON can be found in cereals and derived food products. Several countries have established monitoring programs and guidelines for ZON levels in grain intended for human consumption and animal feed. We have developed a sensitive yeast bioassay allowing detection of the estrogenic activity of ZON in cereal extracts without requiring further clean up steps. The high sensitivity makes this assay suitable for low cost monitoring of contamination of small grain cereals with estrogenicFusarium mycotoxins, but also attractive as a tool for basic research. We have successfully used yeast indicator strains to screen for mutants ofF. graminearum which no longer produce detectable amounts of ZON, and have identified a plant cDNA encoding a ZON detoxification enzyme.
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Affiliation(s)
- R Mitterbauer
- Center of Applied Genetics, BOKU - University of Natural Resources and Applied Life Sciences, A-1190, Vienna, Austria
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