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Prerostova S, Rezek J, Jarosova J, Lacek J, Dobrev P, Marsik P, Gaudinova A, Knirsch V, Dolezal K, Plihalova L, Vanek T, Kieber J, Vankova R. Cytokinins act synergistically with heat acclimation to enhance rice thermotolerance affecting hormonal dynamics, gene expression and volatile emission. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 198:107683. [PMID: 37062127 DOI: 10.1016/j.plaphy.2023.107683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 03/24/2023] [Accepted: 04/03/2023] [Indexed: 05/07/2023]
Abstract
Heat stress is a frequent environmental constraint. Phytohormones can significantly affect plant thermotolerance. This study compares the effects of exogenous cytokinin meta-topolin-9-(tetrahydropyran-2-yl)purine (mT9THP) on rice (Oryza sativa) under control conditions, after acclimation by moderate temperature (A; 37 °C, 2h), heat stress (HS; 45 °C, 6h) and their combination (AHS). mT9THP is a stable cytokinin derivative that releases active meta-topolin gradually, preventing the rapid deactivation reported after exogenous cytokinin application. Under control conditions, mT9THP negatively affected jasmonic acid in leaves and abscisic and salicylic acids in crowns (meristematic tissue crucial for tillering). Exogenous cytokinin stimulated the emission of volatile organic compounds (VOC), especially 2,3-butanediol. Acclimation upregulated trans-zeatin, expression of stress- and hormone-related genes, and VOC emission. The combination of acclimation and mT9THP promoted the expression of stress markers and antioxidant enzymes and moderately increased VOC emission, including 2-ethylhexyl salicylate or furanones. AHS and HS responses shared some common features, namely, increase of ethylene precursor aminocyclopropane-1-carboxylic acid (ACC), cis-zeatin and cytokinin methylthio derivatives, as well as the expression of heat shock proteins, alternative oxidases, and superoxide dismutases. AHS specifically induced jasmonic acid and auxin indole-3-acetic acid levels, diacylglycerolipids with fewer double bonds, and VOC emissions [e.g., acetamide, lipoxygenase (LOX)-derived volatiles]. Under direct HS, exogenous cytokinin mimicked some positive acclimation effects. The combination of mT9THP and AHS had the strongest thermo-protective effect, including a strong stimulation of VOC emissions (including LOX-derived ones). These results demonstrate for the first time the crucial contribution of volatiles to the beneficial effects of cytokinin and AHS on rice thermotolerance.
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Affiliation(s)
- Sylva Prerostova
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Rozvojova 263, 165 02, Prague, Czech Republic.
| | - Jan Rezek
- Laboratory of Plant Biotechnologies, Institute of Experimental Botany, Czech Academy of Sciences, Rozvojova 313, 165 02, Prague, Czech Republic.
| | - Jana Jarosova
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Rozvojova 263, 165 02, Prague, Czech Republic.
| | - Jozef Lacek
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Rozvojova 263, 165 02, Prague, Czech Republic.
| | - Petre Dobrev
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Rozvojova 263, 165 02, Prague, Czech Republic.
| | - Petr Marsik
- Laboratory of Plant Biotechnologies, Institute of Experimental Botany, Czech Academy of Sciences, Rozvojova 313, 165 02, Prague, Czech Republic.
| | - Alena Gaudinova
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Rozvojova 263, 165 02, Prague, Czech Republic.
| | - Vojtech Knirsch
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Rozvojova 263, 165 02, Prague, Czech Republic.
| | - Karel Dolezal
- Laboratory of Growth Regulators, Institute of Experimental Botany, Czech Academy of Sciences, Slechtitelu 27, 783 71, Olomouc, Czech Republic; Department of Chemical Biology, Faculty of Science, Palacky University, 17. listopadu 1192/12, 779 00, Olomouc, Czech Republic.
| | - Lucie Plihalova
- Laboratory of Growth Regulators, Institute of Experimental Botany, Czech Academy of Sciences, Slechtitelu 27, 783 71, Olomouc, Czech Republic; Department of Chemical Biology, Faculty of Science, Palacky University, 17. listopadu 1192/12, 779 00, Olomouc, Czech Republic.
| | - Tomas Vanek
- Laboratory of Plant Biotechnologies, Institute of Experimental Botany, Czech Academy of Sciences, Rozvojova 313, 165 02, Prague, Czech Republic.
| | - Joseph Kieber
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA.
| | - Radomira Vankova
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Rozvojova 263, 165 02, Prague, Czech Republic.
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Antoniadi I, Mateo-Bonmatí E, Pernisová M, Brunoni F, Antoniadi M, Villalonga MGA, Ament A, Karády M, Turnbull C, Doležal K, Pěnčík A, Ljung K, Novák O. IPT9, a cis-zeatin cytokinin biosynthesis gene, promotes root growth. FRONTIERS IN PLANT SCIENCE 2022; 13:932008. [PMID: 36311087 PMCID: PMC9616112 DOI: 10.3389/fpls.2022.932008] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 08/16/2022] [Indexed: 06/12/2023]
Abstract
Cytokinin and auxin are plant hormones that coordinate many aspects of plant development. Their interactions in plant underground growth are well established, occurring at the levels of metabolism, signaling, and transport. Unlike many plant hormone classes, cytokinins are represented by more than one active molecule. Multiple mutant lines, blocking specific parts of cytokinin biosynthetic pathways, have enabled research in plants with deficiencies in specific cytokinin-types. While most of these mutants have confirmed the impeding effect of cytokinin on root growth, the ipt29 double mutant instead surprisingly exhibits reduced primary root length compared to the wild type. This mutant is impaired in cis-zeatin (cZ) production, a cytokinin-type that had been considered inactive in the past. Here we have further investigated the intriguing ipt29 root phenotype, opposite to known cytokinin functions, and the (bio)activity of cZ. Our data suggest that despite the ipt29 short-root phenotype, cZ application has a negative impact on primary root growth and can activate a cytokinin response in the stele. Grafting experiments revealed that the root phenotype of ipt29 depends mainly on local signaling which does not relate directly to cytokinin levels. Notably, ipt29 displayed increased auxin levels in the root tissue. Moreover, analyses of the differential contributions of ipt2 and ipt9 to the ipt29 short-root phenotype demonstrated that, despite its deficiency on cZ levels, ipt2 does not show any root phenotype or auxin homeostasis variation, while ipt9 mutants were indistinguishable from ipt29. We conclude that IPT9 functions may go beyond cZ biosynthesis, directly or indirectly, implicating effects on auxin homeostasis and therefore influencing plant growth.
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Affiliation(s)
- Ioanna Antoniadi
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Eduardo Mateo-Bonmatí
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Markéta Pernisová
- Plant Sciences Core Facility, Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), and NCBR, Faculty of Science, Masaryk University, Brno, Czechia
| | - Federica Brunoni
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences, Olomouc, Czechia
- Laboratory of Growth Regulators, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Mariana Antoniadi
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
| | | | - Anita Ament
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences, Olomouc, Czechia
- Laboratory of Growth Regulators, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Michal Karády
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences, Olomouc, Czechia
- Laboratory of Growth Regulators, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Colin Turnbull
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Karel Doležal
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences, Olomouc, Czechia
- Laboratory of Growth Regulators, Faculty of Science, Palacký University, Olomouc, Czechia
- Department of Chemical Biology, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Aleš Pěnčík
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences, Olomouc, Czechia
- Laboratory of Growth Regulators, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Karin Ljung
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Ondřej Novák
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences, Olomouc, Czechia
- Laboratory of Growth Regulators, Faculty of Science, Palacký University, Olomouc, Czechia
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Savelieva EM, Zenchenko AA, Drenichev MS, Kozlova AA, Kurochkin NN, Arkhipov DV, Chizhov AO, Oslovsky VE, Romanov GA. In Planta, In Vitro and In Silico Studies of Chiral N6-Benzyladenine Derivatives: Discovery of Receptor-Specific S-Enantiomers with Cytokinin or Anticytokinin Activities. Int J Mol Sci 2022; 23:ijms231911334. [PMID: 36232653 PMCID: PMC9569578 DOI: 10.3390/ijms231911334] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/17/2022] [Accepted: 09/19/2022] [Indexed: 01/12/2023] Open
Abstract
Cytokinins, classical phytohormones, affect all stages of plant ontogenesis, but their application in agriculture is limited because of the lack of appropriate ligands, including those specific for individual cytokinin receptors. In this work, a series of chiral N6-benzyladenine derivatives were studied as potential cytokinins or anticytokinins. All compounds contained a methyl group at the α-carbon atom of the benzyl moiety, making them R- or S-enantiomers. Four pairs of chiral nucleobases and corresponding ribonucleosides containing various substituents at the C2 position of adenine heterocycle were synthesized. A nucleophilic substitution reaction by secondary optically active amines was used. A strong influence of the chirality of studied compounds on their interaction with individual cytokinin receptors of Arabidopsis thaliana was uncovered in in vivo and in vitro assays. The AHK2 and CRE1/AHK4 receptors were shown to have low affinity for the studied S-nucleobases while the AHK3 receptor exhibited significant affinity for most of them. Thereby, three synthetic AHK3-specific cytokinins were discovered: N6-((S)-α-methylbenzyl)adenine (S-MBA), 2-fluoro,N6-((S)-α-methylbenzyl)adenine (S-FMBA) and 2-chloro,N6-((S)-α-methylbenzyl)adenine (S-CMBA). Interaction patterns between individual receptors and specific enantiomers were rationalized by structure analysis and molecular docking. Two other S-enantiomers (N6-((S)-α-methylbenzyl)adenosine, 2-amino,N6-((S)-α-methylbenzyl)adenosine) were found to exhibit receptor-specific and chirality-dependent anticytokinin properties.
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Affiliation(s)
- Ekaterina M. Savelieva
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya str. 35, 127276 Moscow, Russia
| | - Anastasia A. Zenchenko
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov str. 32, 119991 Moscow, Russia
| | - Mikhail S. Drenichev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov str. 32, 119991 Moscow, Russia
| | - Anna A. Kozlova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov str. 32, 119991 Moscow, Russia
| | - Nikolay N. Kurochkin
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov str. 32, 119991 Moscow, Russia
| | - Dmitry V. Arkhipov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya str. 35, 127276 Moscow, Russia
| | - Alexander O. Chizhov
- Zelinsky Institute of Organic Chemistry, Russian Academy of Science, Leninsky pr. 47, 119991 Moscow, Russia
| | - Vladimir E. Oslovsky
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov str. 32, 119991 Moscow, Russia
| | - Georgy A. Romanov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya str. 35, 127276 Moscow, Russia
- Correspondence: or
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Del Rosario Cárdenas-Aquino M, Sarria-Guzmán Y, Martínez-Antonio A. Review: Isoprenoid and aromatic cytokinins in shoot branching. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 319:111240. [PMID: 35487650 DOI: 10.1016/j.plantsci.2022.111240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 02/24/2022] [Accepted: 02/26/2022] [Indexed: 06/14/2023]
Abstract
Shoot branching is an important event of plant development that defines growth and reproduction. The BRANCHED1 gene (BRC1/TB1/FC1) is crucial for this process. Within the phytohormones, cytokinins directly activate axillary buds to promote shoot branching. In addition, strigolactones and auxins inhibit bud outgrowth. This review addresses the involvement of aromatic and isoprenoid cytokinins in shoot branching. And how auxins and strigolactones contribute to regulating this process also. The results obtained by others and our working group with lemongrass (Cymbopogon citratus) show that cytokinins affect both shoot and root apical meristem development, consistent with other plant species. However, many questions remain about how cytokinins and strigolactones antagonistically regulate BRC1 gene expression. Additionally, many details of the interaction among cytokinins, auxins, and strigolactones need to be clarified. We will gain a more comprehensive scheme of bud outgrowth with these details.
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Affiliation(s)
| | - Yohanna Sarria-Guzmán
- Facultad de Ingeniería y Ciencias Básicas, Fundación Universitaria del Área Andina, Transv 22 Bis #4-105, Valledupar 200005, Cesar, Colombia
| | - Agustino Martínez-Antonio
- Biological Engineering Laboratory, Cinvestav Irapuato, Km. 9.6 Libramiento Norte Carr. Irapuato-León, Irapuato 36824, Gto, México.
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Photosynthetic Parameters and Oxidative Stress during Acclimation of Crepe-Myrtle (Lagerstroemia speciosa (L.) Pers.) in a meta-Topolin-Based Micropropagation System and Genetic Fidelity of Regenerated Plants. PLANTS 2022; 11:plants11091163. [PMID: 35567164 PMCID: PMC9102070 DOI: 10.3390/plants11091163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/12/2022] [Accepted: 04/23/2022] [Indexed: 12/03/2022]
Abstract
An improved and stable micropropagation system using the cytokinin, meta-Topolin (N6 (3-hydroxybenzylamino purine—mT), with nodal explants in Lagerstroemia speciosa L. was established. Among the different doses of mT, the maximum number of shoots with the highest shoot length was obtained using Murashige and Skoog’s (MS) medium supplemented with 5.0 µM mT. The results were consistent throughout the proliferation period, when recorded at week 4, 8, and 12 of being cultured, with an average of 16.4 shoots per nodal explant, and having a mean length of 4.10 cm at week 8. Shoot proliferation rates could be further improved by a combination of 5.0 µM mT with 0.5 µM α-naphthalene acetic acid in MS medium; nodal explants produced an average of 24.3 shoots with a mean length of 5.74 cm after 8 weeks of being cultured. Among the five different concentrations of three auxins tested for the rooting of microshoots in MS medium, a 1.0 µM indole-3-butyric acid treatment was the best, with an average of 10.3 roots per microshoot at an average length of 3.56 cm in 93% of microshoots within 4 weeks of being transferred to this medium. A significant reduction of both chlorophyll a and b in leaves during the first week of acclimation corresponded with a high accumulation of malondialdehyde (MDH), indicating that lipid peroxidation affected chlorophyll pigments. From the second week of acclimation, photosynthetic pigment content significantly increased and MDH content decreased. The net photosynthetic rate and leaf carotenoid content showed almost linear increases throughout the acclimation period. Activity of antioxidant enzymes, namely, superoxide dismutase, catalase, and peroxidases, consistently increased throughout the acclimation period, corresponding with the accumulation of photosynthetic pigments, thus demonstrating the role of the improved antioxidant enzymatic defense system during acclimation. A comparison of parent plant DNA with that of the greenhouse acclimated plants using random amplified polymorphic DNA and inter-simple sequence repeat markers showed a monomorphic pattern indicating genetic stability and the suitability of the method for micropropagation of L. speciosa.
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Vázquez-Chimalhua E, Barrera-Ortiz S, Valencia-Cantero E, López-Bucio J, Ruiz-Herrera LF. The bacterial volatile N,N-dimethyl-hexadecylamine promotes Arabidopsis primary root elongation through cytokinin signaling and the AHK2 receptor. PLANT SIGNALING & BEHAVIOR 2021; 16:1879542. [PMID: 33586610 PMCID: PMC7971242 DOI: 10.1080/15592324.2021.1879542] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
N,N-dimethyl-hexadecylamine (DMHDA) is a volatile organic compound (VOC) produced by some plant growth-promoting rhizobacteria (PGPR), which inhibits the growth of pathogenic fungi and induces iron uptake by roots. In this report, through the application of a wide range of concentrations, we found that DMHDA affects Arabidopsis primary root growth and lateral root formation in a dose-dependent manner where 1 and 2 µM promoted root growth and higher (4-32 µM) concentrations repressed growth. Cytokinin-inducible TCS::GFP and ARR5::uidA gene constructs showed an increased expression in columella cells and root meristem, respectively, at 2 µM DMHDA, but their expression domains strongly diminished at growth repressing treatments. To test if either primary root growth promotion or repression could involve members of the cytokinin receptor family, the growth of WT and double mutant combinations cre1-12 ahk2-2, cre1-12 ahk3-3, and ahk2-2 ahk3-3 was tested in control conditions or supplemented with 2 µM or 16 µM DMHDA. Noteworthy, the root growth promotion disappeared in cre1-12 ahk2-2 and ahk2-2 ahk3-3 combinations, whereas all double mutants had higher repression than the WT at high doses. We further show that DMHDA fails to mimic the effects of ethylene in Arabidopsis seedlings grown in darkness that include an exaggerated apical hook, stem and root shortening, and root hair elongation. Our data help unravel how Arabidopsis senses a growth-modulating bacterial volatile through changes in cytokinin responsiveness.
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Affiliation(s)
- Ernesto Vázquez-Chimalhua
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo. Edificio B3, Ciudad Universitaria, Morelia, Michoacán, México
| | - Salvador Barrera-Ortiz
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo. Edificio B3, Ciudad Universitaria, Morelia, Michoacán, México
| | - Eduardo Valencia-Cantero
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo. Edificio B3, Ciudad Universitaria, Morelia, Michoacán, México
| | - José López-Bucio
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo. Edificio B3, Ciudad Universitaria, Morelia, Michoacán, México
| | - León Francisco Ruiz-Herrera
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo. Edificio B3, Ciudad Universitaria, Morelia, Michoacán, México
- CONTACT León Francisco Ruiz-Herrera Avenida Francisco J. Múgica S/N, Ciudad Universitaria, C.P. 58030
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The Hulks and the Deadpools of the Cytokinin Universe: A Dual Strategy for Cytokinin Production, Translocation, and Signal Transduction. Biomolecules 2021; 11:biom11020209. [PMID: 33546210 PMCID: PMC7913349 DOI: 10.3390/biom11020209] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 01/27/2021] [Accepted: 01/28/2021] [Indexed: 02/06/2023] Open
Abstract
Cytokinins are plant hormones, derivatives of adenine with a side chain at the N6-position. They are involved in many physiological processes. While the metabolism of trans-zeatin and isopentenyladenine, which are considered to be highly active cytokinins, has been extensively studied, there are others with less obvious functions, such as cis-zeatin, dihydrozeatin, and aromatic cytokinins, which have been comparatively neglected. To help explain this duality, we present a novel hypothesis metaphorically comparing various cytokinin forms, enzymes of CK metabolism, and their signalling and transporter functions to the comics superheroes Hulk and Deadpool. Hulk is a powerful but short-lived creation, whilst Deadpool presents a more subtle and enduring force. With this dual framework in mind, this review compares different cytokinin metabolites, and their biosynthesis, translocation, and sensing to illustrate the different mechanisms behind the two CK strategies. This is put together and applied to a plant developmental scale and, beyond plants, to interactions with organisms of other kingdoms, to highlight where future study can benefit the understanding of plant fitness and productivity.
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Cytokinin N-glucosides: Occurrence, Metabolism and Biological Activities in Plants. Biomolecules 2020; 11:biom11010024. [PMID: 33379369 PMCID: PMC7824008 DOI: 10.3390/biom11010024] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 12/22/2020] [Accepted: 12/24/2020] [Indexed: 01/11/2023] Open
Abstract
Cytokinins (CKs) are a class of phytohormones affecting many aspects of plant growth and development. In the complex process of CK homeostasis in plants, N-glucosylation represents one of the essential metabolic pathways. Its products, CK N7- and N9-glucosides, have been largely overlooked in the past as irreversible and inactive CK products lacking any relevant physiological impact. In this work, we report a widespread distribution of CK N-glucosides across the plant kingdom proceeding from evolutionary older to younger plants with different proportions between N7- and N9-glucosides in the total CK pool. We show dramatic changes in their profiles as well as in expression levels of the UGT76C1 and UGT76C2 genes during Arabidopsis ontogenesis. We also demonstrate specific physiological effects of CK N-glucosides in CK bioassays including their antisenescent activities, inhibitory effects on root development, and activation of the CK signaling pathway visualized by the CK-responsive YFP reporter line, TCSv2::3XVENUS. Last but not least, we present the considerable impact of CK N7- and N9-glucosides on the expression of CK-related genes in maize and their stimulatory effects on CK oxidase/dehydrogenase activity in oats. Our findings revise the apparent irreversibility and inactivity of CK N7- and N9-glucosides and indicate their involvement in CK evolution while suggesting their unique function(s) in plants.
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Oshchepkov MS, Kalistratova AV, Savelieva EM, Romanov GA, Bystrova NA, Kochetkov KA. Natural and synthetic cytokinins and their applications in biotechnology, agrochemistry and medicine. RUSSIAN CHEMICAL REVIEWS 2020. [DOI: 10.1070/rcr4921] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The review is devoted to cytokinins — classical plant hormones known for more than six decades. Nevertheless, different aspects of the action of cytokinins are still being investigated. Relevant studies produced interesting, often unexpected, results, which cast doubt on the old paradigms and open new prospects for the use of these phytohormones. Particular attention is given to recent advances in the applications of natural cytokinins and their synthetic analogues in biotechnology, agriculture, medicine and cosmetics. The chemical synthesis, properties and the possible use of artificial cytokinins are considered in detail. The review is aimed at researchers interested in the development and applications of new biologically active compounds with a wide spectrum of action on diverse biological objects, from plants to humans.
The bibliography includes 233 references.
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Bryksová M, Dabravolski S, Kučerová Z, Zavadil Kokáš F, Špundová M, Plíhalová L, Takáč T, Grúz J, Hudeček M, Hloušková V, Koprna R, Novák O, Strnad M, Plíhal O, Doležal K. Aromatic Cytokinin Arabinosides Promote PAMP-like Responses and Positively Regulate Leaf Longevity. ACS Chem Biol 2020; 15:1949-1963. [PMID: 32520524 DOI: 10.1021/acschembio.0c00306] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cytokinins are plant hormones with biological functions ranging from coordination of plant growth to the regulation of biotic and abiotic stress-related responses and senescence. The components of the plant immune system can learn from past elicitations by microbial pathogens and herbivores and adapt to new threats. It is known that plants can enter the primed state of enhanced defense induced by either natural or synthetic compounds. While the involvement of cytokinins in defense priming has been documented, no comprehensive model of their action has been provided to date. Here, we report the functional characterization of two aromatic cytokinin derivatives, 6-benzylaminopurine-9-arabinosides (BAPAs), 3-methoxy-BAPA and 3-hydroxy-BAPA, that proved to be effective in delaying senescence in detached leaves while having low interactions with the cytokinin pathway. An RNA-seq profiling study on Arabidopsis leaves treated with 3-methoxy-BAPA revealed that short and extended treatments with this compound shifted the transcriptional response markedly toward defense. Both treatments revealed upregulation of genes involved in processes associated with plant innate immunity such as cell wall remodeling and upregulation of specific MAP kinases, most importantly MPK11, which is a MAPK module involved in stress-related signaling during the pathogen-associated molecular patterns (PAMPs) response. In addition, elevated levels of JA and its metabolites, jasmonate/ethylene-driven upregulation of PLANT DEFENSIN 1.2 (PDF1.2) and other defensins, and also temporarily elevated levels of reactive oxygen species marked the plant response to 3-methoxy-BAPA treatment. Synergistic interactions were observed when plants were cotreated with 3-hydroxy-BAPA and the flagellin-derived bacterial PAMP peptide (flg22), leading to the enhanced expression of the PAMP-triggered immunity (PTI) marker gene FRK1. Our data collectively show that some BAPAs can sensitively prime the PTI responses in a low micromolar range of concentrations while having no observable negative effects on the overall fitness of the plant.
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Affiliation(s)
- Magdaléna Bryksová
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
| | - Siarhei Dabravolski
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
| | - Zuzana Kučerová
- Department of Biophysics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
| | - Filip Zavadil Kokáš
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
- Regional Centre for Applied Molecular Oncology (RECAMO), Masaryk Memorial Cancer Institute, Žlutý kopec 7, CZ-65653 Brno, Czech Republic
| | - Martina Špundová
- Department of Biophysics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
| | - Lucie Plíhalová
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences & Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
| | - Tomáš Takáč
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
| | - Jiří Grúz
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences & Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
| | - Martin Hudeček
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences & Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
| | - Veronika Hloušková
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences & Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
| | - Radoslav Koprna
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
| | - Ondřej Novák
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences & Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
| | - Miroslav Strnad
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences & Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
| | - Ondřej Plíhal
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences & Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
| | - Karel Doležal
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences & Faculty of Science, Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
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11
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Vylíčilová H, Bryksová M, Matušková V, Doležal K, Plíhalová L, Strnad M. Naturally Occurring and Artificial N9-Cytokinin Conjugates: From Synthesis to Biological Activity and Back. Biomolecules 2020; 10:biom10060832. [PMID: 32485963 PMCID: PMC7356397 DOI: 10.3390/biom10060832] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/26/2020] [Accepted: 05/26/2020] [Indexed: 01/18/2023] Open
Abstract
Cytokinins and their sugar or non-sugar conjugates are very active growth-promoting factors in plants, although they occur at very low concentrations. These compounds have been identified in numerous plant species. This review predominantly focuses on 9-substituted adenine-based cytokinin conjugates, both artificial and endogenous, sugar and non-sugar, and their roles in plants. Acquired information about their biological activities, interconversions, and metabolism improves understanding of their mechanisms of action and functions in planta. Although a number of 9-substituted cytokinins occur endogenously, many have also been prepared in laboratories to facilitate the clarification of their physiological roles and the determination of their biological properties. Here, we chart advances in knowledge of 9-substituted cytokinin conjugates from their discovery to current understanding and reciprocal interactions between biological properties and associated structural motifs. Current organic chemistry enables preparation of derivatives with better biological properties, such as improved anti-senescence, strong cell division stimulation, shoot forming, or more persistent stress tolerance compared to endogenous or canonical cytokinins. Many artificial cytokinin conjugates stimulate higher mass production than naturally occurring cytokinins, improve rooting, or simply have high stability or bioavailability. Thus, knowledge of the biosynthesis, metabolism, and activity of 9-substituted cytokinins in various plant species extends the scope for exploiting both natural and artificially prepared cytokinins in plant biotechnology, tissue culture, and agriculture.
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Affiliation(s)
- Hana Vylíčilová
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic; (H.V.); (M.B.); (V.M.); (K.D.)
| | - Magdaléna Bryksová
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic; (H.V.); (M.B.); (V.M.); (K.D.)
| | - Vlasta Matušková
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic; (H.V.); (M.B.); (V.M.); (K.D.)
| | - Karel Doležal
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic; (H.V.); (M.B.); (V.M.); (K.D.)
- Laboratory of Growth Regulators, Palacký University & Institute of Experimental Botany ASCR, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic;
| | - Lucie Plíhalová
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic; (H.V.); (M.B.); (V.M.); (K.D.)
- Laboratory of Growth Regulators, Palacký University & Institute of Experimental Botany ASCR, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic;
- Correspondence:
| | - Miroslav Strnad
- Laboratory of Growth Regulators, Palacký University & Institute of Experimental Botany ASCR, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic;
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12
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Hoyerová K, Hošek P. New Insights Into the Metabolism and Role of Cytokinin N-Glucosides in Plants. FRONTIERS IN PLANT SCIENCE 2020; 11:741. [PMID: 32582261 PMCID: PMC7292203 DOI: 10.3389/fpls.2020.00741] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 05/08/2020] [Indexed: 05/18/2023]
Abstract
Cytokinin (CK) N-glucosides are the most abundant group of CK metabolites in many species; however, their physiological role in planta was for a long time perceived as irreversible storage CK forms only. Recently, a comprehensive screen showed that only vascular plants form CK N-glucosides in contrast to mosses, algae, and fungi. The formation of CK N-glucosides as biologically inactive CK conjugates thus represents an evolutionarily young mechanism for deactivation of CK bases. Even though CK N-glucosides are not biologically active themselves due to their inability to activate the CK perception system, new data on CK N-glucoside metabolism show that trans-zeatin (tZ) N7- and N9-glucosides are metabolized in vivo, efficiently releasing free CK bases that are most probably responsible for the biological activities observed in a number of bioassays. Moreover, CK N-glucosides' subcellular localization as well as their abundance in xylem both point to their possible plasma membrane transport and indicate a role also as CK transport forms. Identification of the enzyme(s) responsible for the hydrolysis of tZ N7- and N9-glucosides, as well as the discovery of putative CK N-glucoside plasma membrane transporter, would unveil important parts of the overall picture of CK metabolic interconversions and their physiological importance.
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13
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Bryksová M, Hybenová A, Hernándiz AE, Novák O, Pěnčík A, Spíchal L, De Diego N, Doležal K. Hormopriming to Mitigate Abiotic Stress Effects: A Case Study of N 9-Substituted Cytokinin Derivatives With a Fluorinated Carbohydrate Moiety. FRONTIERS IN PLANT SCIENCE 2020; 11:599228. [PMID: 33362831 PMCID: PMC7758400 DOI: 10.3389/fpls.2020.599228] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 11/16/2020] [Indexed: 05/02/2023]
Abstract
Drought and salinity reduce seed germination, seedling emergence, and early seedling establishment, affect plant metabolism, and hence, reduce crop yield. Development of technologies that can increase plant tolerance of these challenging growth conditions is a major current interest among plant scientists and breeders. Seed priming has become established as one of the practical approaches that can alleviate the negative impact of many environmental stresses and improve the germination and overall performance of crops. Hormopriming using different plant growth regulators has been widely demonstrated as effective, but information about using cytokinins (CKs) as priming agents is limited to only a few studies using kinetin or 6-benzylaminopurine (BAP). Moreover, the mode of action of these compounds in improving seed and plant fitness through priming has not yet been studied. For many years, BAP has been one of the CKs most commonly applied exogenously to plants to delay senescence and reduce the impact of stress. However, rapid endogenous N 9-glucosylation of BAP can result in negative effects. This can be suppressed by hydroxylation of the benzyl ring or by appropriate N 9 purine substitution. Replacement of the 2' or 3' hydroxyl groups of a nucleoside with a fluorine atom has shown promising results in drug research and biochemistry as a means of enhancing biological activity and increasing chemical or metabolic stability. Here, we show that the application of this chemical modification in four new N 9-substituted CK derivatives with a fluorinated carbohydrate moiety improved the antisenescence properties of CKs. Besides, detailed phenotypical analysis of the growth and development of Arabidopsis plants primed with the new CK analogs over a broad concentration range and under various environmental conditions revealed that they improve growth regulation and antistress activity. Seed priming with, for example, 6-(3-hydroxybenzylamino)-2'-deoxy-2'-fluoro-9-(β)-D-arabinofuranosylpurine promoted plant growth under control conditions and alleviated the negative effects of the salt and osmotic stress. The mode of action of this hormopriming and its effect on plant metabolism were further analyzed through quantification of the endogenous levels of phytohormones such as CKs, auxins and abscisic acid, and the results are discussed.
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Affiliation(s)
- Magdaléna Bryksová
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Andrea Hybenová
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Alba E. Hernándiz
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Ondřej Novák
- Laboratory of Growth Regulators, Palacký University and Institute of Experimental Botany, Czech Academy of Sciences, Olomouc, Czechia
| | - Aleš Pěnčík
- Laboratory of Growth Regulators, Palacký University and Institute of Experimental Botany, Czech Academy of Sciences, Olomouc, Czechia
| | - Lukáš Spíchal
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Nuria De Diego
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Olomouc, Czechia
- *Correspondence: Nuria De Diego,
| | - Karel Doležal
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Olomouc, Czechia
- Laboratory of Growth Regulators, Palacký University and Institute of Experimental Botany, Czech Academy of Sciences, Olomouc, Czechia
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Gasparis S, Przyborowski M, Kała M, Nadolska-Orczyk A. Knockout of the HvCKX1 or HvCKX3 Gene in Barley ( Hordeum vulgare L.) by RNA-Guided Cas9 Nuclease Affects the Regulation of Cytokinin Metabolism and Root Morphology. Cells 2019; 8:E782. [PMID: 31357516 PMCID: PMC6721474 DOI: 10.3390/cells8080782] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 07/19/2019] [Accepted: 07/25/2019] [Indexed: 12/16/2022] Open
Abstract
Barley is among four of the most important cereal crops with respect to global production. Increasing barley yields to desired levels can be achieved by the genetic manipulation of cytokinin content. Cytokinins are plant hormones that regulate many developmental processes and have a strong influence on grain yield. Cytokinin homeostasis is regulated by members of several multigene families. CKX genes encode the cytokinin oxidase/dehydrogenase enzyme, which catalyzes the irreversible degradation of cytokinin. Several recent studies have demonstrated that the RNAi-based silencing of CKX genes leads to increased grain yields in some crop species. To assess the possibility of increasing the grain yield of barley by knocking out CKX genes, we used an RNA-guided Cas9 system to generate ckx1 and ckx3 mutant lines with knockout mutations in the HvCKX1 and HvCKX3 genes, respectively. Homozygous, transgene-free mutant lines were subsequently selected and analyzed. A significant decrease in CKX enzyme activity was observed in the spikes of the ckx1 lines, while in the ckx3 lines, the activity remained at a similar level to that in the control plants. Despite these differences, no changes in grain yield were observed in either mutant line. In turn, differences in CKX activity in the roots between the ckx1 and ckx3 mutants were reflected via root morphology. The decreased CKX activity in the ckx1 lines corresponded to greater root length, increased surface area, and greater numbers of root hairs, while the increased CKX activity in the ckx3 mutants gave the opposite results. RNA-seq analysis of the spike and root transcriptomes revealed an altered regulation of genes controlling cytokinin metabolism and signaling, as well as other genes that are important during seed development, such as those that encode nutrient transporters. The observed changes suggest that the knockout of a single CKX gene in barley may be not sufficient for disrupting cytokinin homeostasis or increasing grain yields.
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Affiliation(s)
- Sebastian Gasparis
- Department of Functional Genomics, Plant Breeding and Acclimatization Institute-National Research Institute, Radzików, 05-870 Błonie, Poland.
| | - Mateusz Przyborowski
- Department of Functional Genomics, Plant Breeding and Acclimatization Institute-National Research Institute, Radzików, 05-870 Błonie, Poland
| | - Maciej Kała
- Department of Functional Genomics, Plant Breeding and Acclimatization Institute-National Research Institute, Radzików, 05-870 Błonie, Poland
| | - Anna Nadolska-Orczyk
- Department of Functional Genomics, Plant Breeding and Acclimatization Institute-National Research Institute, Radzików, 05-870 Błonie, Poland
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15
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Strigolactone promotes cytokinin degradation through transcriptional activation of CYTOKININ OXIDASE/DEHYDROGENASE 9 in rice. Proc Natl Acad Sci U S A 2019; 116:14319-14324. [PMID: 31235564 PMCID: PMC6628823 DOI: 10.1073/pnas.1810980116] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Strigolactone plays a vital role in plant growth and development, but its response genes remain to be identified. In this study, we found that cytokinin content is markedly increased in the strigolactone signaling mutant d53, and that OsCKX9, which encodes a cytokinin oxidase to catalyze the degradation of cytokinin, functions as a primary strigolactone-responsive gene to regulate rice tillering, plant height, and panicle size, likely via a secondary response gene, OsRR5, which encodes a cytokinin-inducible rice type-A response regulator, demonstrating that strigolactone regulates rice shoot architecture through enhanced cytokinin catabolism by modulating OsCKX9 expression. Strigolactones (SLs), a group of terpenoid lactones derived from carotenoids, are plant hormones that control numerous aspects of plant development. Although the framework of SL signaling that the repressor DWARF 53 (D53) could be SL-dependently degraded via the SL receptor D14 and F-box protein D3 has been established, the downstream response genes to SLs remain to be elucidated. Here we show that the cytokinin (CK) content is dramatically increased in shoot bases of the rice SL signaling mutant d53. By examining transcript levels of all the CK metabolism-related genes after treatment with SL analog GR24, we identified CYTOKININ OXIDASE/DEHYDROGENASE 9 (OsCKX9) as a primary response gene significantly up-regulated within 1 h of treatment in the wild type but not in d53. We also found that OsCKX9 functions as a cytosolic and nuclear dual-localized CK catabolic enzyme, and that the overexpression of OsCKX9 suppresses the browning of d53 calli. Both the CRISPR/Cas9-generated OsCKX9 mutants and OsCKX9-overexpressing transgenic plants showed significant increases in tiller number and decreases in plant height and panicle size, suggesting that the homeostasis of OsCKX9 plays a critical role in regulating rice shoot architecture. Moreover, we identified the CK-inducible rice type-A response regulator OsRR5 as the secondary SL-responsive gene, whose expression is significantly repressed after 4 h of GR24 treatment in the wild type but not in osckx9. These findings reveal a comprehensive plant hormone cross-talk in which SL can induce the expression of OsCKX9 to down-regulate CK content, which in turn triggers the response of downstream genes.
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16
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Hönig M, Plíhalová L, Husičková A, Nisler J, Doležal K. Role of Cytokinins in Senescence, Antioxidant Defence and Photosynthesis. Int J Mol Sci 2018; 19:E4045. [PMID: 30558142 PMCID: PMC6321018 DOI: 10.3390/ijms19124045] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 12/05/2018] [Accepted: 12/12/2018] [Indexed: 01/13/2023] Open
Abstract
Cytokinins modulate a number of important developmental processes, including the last phase of leaf development, known as senescence, which is associated with chlorophyll breakdown, photosynthetic apparatus disintegration and oxidative damage. There is ample evidence that cytokinins can slow down all these senescence-accompanying changes. Here, we review relationships between the various mechanisms of action of these regulatory molecules. We highlight their connection to photosynthesis, the pivotal process that generates assimilates, however may also lead to oxidative damage. Thus, we also focus on cytokinin induction of protective responses against oxidative damage. Activation of antioxidative enzymes in senescing tissues is described as well as changes in the levels of naturally occurring antioxidative compounds, such as phenolic acids and flavonoids, in plant explants. The main goal of this review is to show how the biological activities of cytokinins may be related to their chemical structure. New links between molecular aspects of natural cytokinins and their synthetic derivatives with antisenescent properties are described. Structural motifs in cytokinin molecules that may explain why these molecules play such a significant regulatory role are outlined.
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Affiliation(s)
- Martin Hönig
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic.
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University & Institute of Experimental Botany ASCR, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic.
| | - Lucie Plíhalová
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic.
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University & Institute of Experimental Botany ASCR, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic.
| | - Alexandra Husičková
- Department of Biophysics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic.
| | - Jaroslav Nisler
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic.
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University & Institute of Experimental Botany ASCR, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic.
| | - Karel Doležal
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic.
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University & Institute of Experimental Botany ASCR, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic.
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17
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Savelieva EM, Oslovsky VE, Karlov DS, Kurochkin NN, Getman IA, Lomin SN, Sidorov GV, Mikhailov SN, Osolodkin DI, Romanov GA. Cytokinin activity of N 6-benzyladenine derivatives assayed by interaction with the receptors in planta, in vitro, and in silico. PHYTOCHEMISTRY 2018; 149:161-177. [PMID: 29544164 DOI: 10.1016/j.phytochem.2018.02.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 02/11/2018] [Accepted: 02/14/2018] [Indexed: 06/08/2023]
Abstract
Biological effects of hormones in both plants and animals are based on high-affinity interaction with cognate receptors resulting in their activation. The signal of cytokinins, classical plant hormones, is perceived in Arabidopsis by three homologous membrane receptors: AHK2, AHK3, and CRE1/AHK4. To study the cytokinin-receptor interaction, we used 25 derivatives of potent cytokinin N6-benzyladenine (BA) with substituents in the purine heterocycle and/or in the side chain. The study was focused primarily on individual cytokinin receptors from Arabidopsis. The main in planta assay system was based on Arabidopsis double mutants retaining only one isoform of cytokinin receptors and harboring cytokinin-sensitive reporter gene. Classical cytokinin biotest with Amaranthus seedlings was used as an additional biotest. In parallel, the binding of ligands to individual cytokinin receptors was assessed in the in vitro test system. Quantitative comparison of results of different assays confirmed the partial similarity of ligand-binding properties of receptor isoforms. Substituents at positions 8 and 9 of adenine moiety, elongated linker up to 4 methylene units, and replacement of N6 by sulfur or oxygen have resulted in the suppression of cytokinin activity of the derivative toward all receptors. Introduction of a halogen into position 2 of adenine moiety, on the contrary, often increased the ligand activity, especially toward AHK3. Features both common and distinctive of cytokinin receptors in Arabidopsis and Amaranthus were revealed, highlighting species specificity of the cytokinin perception apparatus. Correlations between the extent to which a compound binds to a receptor in vitro and its ability to activate the same receptor in planta were evaluated for each AHK protein. Interaction patterns between individual receptors and ligands were rationalized by structure analysis and molecular docking in sensory modules of AHK receptors. The best correlation between docking scores and specific binding was observed for AHK3. In addition, receptor-specific ligands have been discovered with unique properties to predominantly activate or block distinct cytokinin receptors. These ligands are promising for practical application and as molecular tools in the study of the cytokinin perception by plant cells.
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Affiliation(s)
- Ekaterina M Savelieva
- Laboratory of Signaling Systems of Ontogeny Control, Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, 127276 Moscow, Russia.
| | - Vladimir E Oslovsky
- Laboratory of Design and Synthesis of Biologically Active Compounds, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str. 32, 119991 Russia.
| | - Dmitry S Karlov
- Skolkovo Institute of Science and Technology, Skolkovo Innovation Center, Moscow, 143026 Russia; Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1/3, 119991 Moscow, Russia; Institute of Physiologically Active Compounds, Russian Academy of Sciences, Severny Proezd 1, Chernogolovka, Moscow Region, 142432 Russia.
| | - Nikolay N Kurochkin
- Laboratory of Design and Synthesis of Biologically Active Compounds, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str. 32, 119991 Russia.
| | - Irina A Getman
- Laboratory of Signaling Systems of Ontogeny Control, Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, 127276 Moscow, Russia.
| | - Sergey N Lomin
- Laboratory of Signaling Systems of Ontogeny Control, Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, 127276 Moscow, Russia.
| | - Georgy V Sidorov
- Laboratory of Isotope Labelled Physiologically Active Compounds, Institute of Molecular Genetics, Russian Academy of Sciences, Pl. Akad. Kurchatova 2, 123182 Moscow, Russia.
| | - Sergey N Mikhailov
- Laboratory of Design and Synthesis of Biologically Active Compounds, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str. 32, 119991 Russia.
| | - Dmitry I Osolodkin
- Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1/3, 119991 Moscow, Russia; Institute of Poliomyelitis and Viral Encephalitides, FSBSI Chumakov FSC R&D IBP RAS, Poselok Instituta Poliomelita 8 bd. 1, Poselenie Moskovsky, Moscow 108819, Russia; Institute of Pharmacy and Translational Medicine, Sechenov First Moscow State Medical University, Trubetskaya Str. 8, Moscow 119991, Russia.
| | - Georgy A Romanov
- Laboratory of Signaling Systems of Ontogeny Control, Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, 127276 Moscow, Russia; Department of Molecular Basis of Ontogenesis, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, Bld. 40, 119992 Moscow, Russia.
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18
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Kirschner GK, Stahl Y, Imani J, von Korff M, Simon R. Fluorescent reporter lines for auxin and cytokinin signalling in barley (Hordeum vulgare). PLoS One 2018; 13:e0196086. [PMID: 29694399 PMCID: PMC5918912 DOI: 10.1371/journal.pone.0196086] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 04/05/2018] [Indexed: 11/18/2022] Open
Abstract
The phytohormones auxin and cytokinin control development and maintenance of plant meristems and stem cell systems. Fluorescent protein reporter lines that monitor phytohormone controlled gene expression programmes have been widely used to study development and differentiation in the model species Arabidopsis, but equivalent tools are still missing for the majority of crop species. Barley (Hordeum vulgare) is the fourth most abundant cereal crop plant, but knowledge on these important phytohormones in regard to the barley root and shoot stem cell niches is still negligible. We have now analysed the role of auxin and cytokinin in barley root meristem development, and present fluorescent protein reporter lines that allow to dissect auxin and cytokinin signalling outputs in vivo. We found that application of either auxin or cytokinin to barley seedlings negatively impacts root meristem growth. We further established a barley cytokinin reporter, TCSnew, which revealed significant cytokinin signalling in the stele cells proximal to the QC, and in the differentiated root cap cells. Application of exogenous cytokinin activated signalling in the root stem cell niche. Commonly employed auxin reporters DR5 or DR5v2 failed to respond to auxin in barley. However, analysis of putative auxin signalling targets barley PLETHORA1 (HvPLT1) is expressed in a similar pattern as its orthologue AtPLT1 from Arabidopsis, i.e. in the QC and the surrounding cells. Furthermore, the PINFORMED1 (HvPIN1) auxin efflux carrier was found to be expressed in root and shoot meristems, where it polarly localized to the plasma membrane. HvPIN1 expression is negatively regulated by cytokinin and its intracellular localisation is sensitive to brefeldinA (BFA). With this study, we provide the first fluorescent reporter lines as a tool to study auxin and cytokinin signalling and response pathways in barley.
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Affiliation(s)
- Gwendolyn K. Kirschner
- Institute for Developmental Genetics and Cluster of Excellence on Plant Sciences, Heinrich Heine University, Düsseldorf, Germany
| | - Yvonne Stahl
- Institute for Developmental Genetics and Cluster of Excellence on Plant Sciences, Heinrich Heine University, Düsseldorf, Germany
| | - Jafargholi Imani
- Research Centre for BioSystems, Land Use and Nutrition (IFZ), Justus Liebig University, Institute of Phytopathology and Applied Zoology, Giessen, Germany
| | - Maria von Korff
- Institute for Plant Genetics and Cluster of Excellence on Plant Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Rüdiger Simon
- Institute for Developmental Genetics and Cluster of Excellence on Plant Sciences, Heinrich Heine University, Düsseldorf, Germany
- * E-mail:
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Plíhalová L, Vylíčilová H, Doležal K, Zahajská L, Zatloukal M, Strnad M. Synthesis of aromatic cytokinins for plant biotechnology. N Biotechnol 2016; 33:614-624. [DOI: 10.1016/j.nbt.2015.11.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 11/11/2015] [Accepted: 11/27/2015] [Indexed: 11/25/2022]
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20
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Zalabák D, Johnová P, Plíhal O, Šenková K, Šamajová O, Jiskrová E, Novák O, Jackson D, Mohanty A, Galuszka P. Maize cytokinin dehydrogenase isozymes are localized predominantly to the vacuoles. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2016; 104:114-24. [PMID: 27031423 DOI: 10.1016/j.plaphy.2016.03.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 03/09/2016] [Accepted: 03/10/2016] [Indexed: 05/12/2023]
Abstract
The maize genome encompasses 13 genes encoding for cytokinin dehydrogenase isozymes (CKXs). These enzymes are responsible for irreversible degradation of cytokinin plant hormones and thus, contribute regulating their levels. Here, we focus on the unique aspect of CKXs: their diverse subcellular distribution, important in regulating cytokinin homeostasis. Maize CKXs were tagged with green fluorescent protein (GFP) and transiently expressed in maize protoplasts. Most of the isoforms, namely ZmCKX1, ZmCKX2, ZmCKX4a, ZmCKX5, ZmCKX6, ZmCKX8, ZmCKX9, and ZmCKX12, were associated with endoplasmic reticulum (ER) several hours after transformation. GFP-fused CKXs were observed to accumulate in putative prevacuolar compartments. To gain more information about the spatiotemporal localization of the above isoforms, we prepared stable expression lines of all ZmCKX-GFP fusions in Arabidopsis thaliana Ler suspension culture. All the ER-associated isoforms except ZmCKX1 and ZmCKX9 were found to be targeted primarily to vacuoles, suggesting that ER-localization is a transition point in the intracellular secretory pathway and vacuoles serve as these isoforms' final destination. ZmCKX9 showed an ER-like localization pattern similar to those observed in the transient maize assay. Apoplastic localization of ZmCKX1 was further confirmed and ZmCKX10 showed cytosolic/nuclear localization due to the absence of the signal peptide sequence as previously reported. Additionally, we prepared GFP-fused N-terminal signal deletion mutants of ZmCKX2 and ZmCKX9 and clearly demonstrated that the localization pattern of these mutant forms was cytosolic/nuclear. This study provides the first complex model for spatiotemporal localization of the key enzymes of the cytokinin degradation/catabolism in monocotyledonous plants.
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Affiliation(s)
- David Zalabák
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Šlechtitelů 27, Olomouc 783 71, Czech Republic
| | - Patricie Johnová
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Šlechtitelů 27, Olomouc 783 71, Czech Republic
| | - Ondřej Plíhal
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Šlechtitelů 27, Olomouc 783 71, Czech Republic
| | - Karolina Šenková
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Šlechtitelů 27, Olomouc 783 71, Czech Republic
| | - Olga Šamajová
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Šlechtitelů 27, Olomouc 783 71, Czech Republic
| | - Eva Jiskrová
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Šlechtitelů 27, Olomouc 783 71, Czech Republic
| | - Ondřej Novák
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Šlechtitelů 27, Olomouc 783 71, Czech Republic
| | - David Jackson
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Amitabh Mohanty
- DuPont Pioneer Ag Biotech, DuPont Knowledge Centre, Turkapally Village, Hyderabad 500078, Telangana, India
| | - Petr Galuszka
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Šlechtitelů 27, Olomouc 783 71, Czech Republic.
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21
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Hluska T, Dobrev PI, Tarkowská D, Frébortová J, Zalabák D, Kopečný D, Plíhal O, Kokáš F, Briozzo P, Zatloukal M, Motyka V, Galuszka P. Cytokinin metabolism in maize: Novel evidence of cytokinin abundance, interconversions and formation of a new trans-zeatin metabolic product with a weak anticytokinin activity. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 247:127-37. [PMID: 27095406 DOI: 10.1016/j.plantsci.2016.03.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Revised: 03/25/2016] [Accepted: 03/28/2016] [Indexed: 05/10/2023]
Abstract
Cytokinins (CKs) are an important group of phytohormones. Their tightly regulated and balanced levels are essential for proper cell division and plant organ development. Here we report precise quantification of CK metabolites and other phytohormones in maize reproductive organs in the course of pollination and kernel maturation. A novel enzymatic activity dependent on NADP(+) converting trans-zeatin (tZ) to 6-(3-methylpyrrol-1-yl)purine (MPP) was detected. MPP shows weak anticytokinin properties and inhibition of CK dehydrogenases due to their ability to bind to an active site in the opposite orientation than substrates. Although the physiological significance of tZ side-chain cyclization is not anticipated as the MPP occurrence in maize tissue is very low, properties of the novel CK metabolite indicate its potential for utilization in plant in vitro tissue culture. Furthermore, feeding experiments with different isoprenoid CKs revealed distinct preferences in glycosylation of tZ and cis-zeatin (cZ). While tZ is preferentially glucosylated at the N9 position, cZ forms mainly O-glucosides. Since O-glucosides, in contrast to N9-glucosides, are resistant to irreversible cleavage catalyzed by CK dehydrogenases, the observed preference of maize CK glycosyltransferases to O-glycosylate zeatin in the cis-position might be a reason why cZ derivatives are over-accumulated in different maize tissues and organs.
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Affiliation(s)
- Tomáš Hluska
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Petre I Dobrev
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Rozvojová 263, 165 02 Prague, Czech Republic
| | - Dana Tarkowská
- Department of Metabolomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Jitka Frébortová
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - David Zalabák
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - David Kopečný
- Department of Protein Biochemistry and Proteomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - Ondřej Plíhal
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Filip Kokáš
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Pierre Briozzo
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, Route de Saint-Cyr, F-78026, Versailles, France
| | - Marek Zatloukal
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - Václav Motyka
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Rozvojová 263, 165 02 Prague, Czech Republic
| | - Petr Galuszka
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic.
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22
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Vylíčilová H, Husičková A, Spíchal L, Srovnal J, Doležal K, Plíhal O, Plíhalová L. C2-substituted aromatic cytokinin sugar conjugates delay the onset of senescence by maintaining the activity of the photosynthetic apparatus. PHYTOCHEMISTRY 2016; 122:22-33. [PMID: 26706318 DOI: 10.1016/j.phytochem.2015.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 11/29/2015] [Accepted: 12/02/2015] [Indexed: 05/04/2023]
Abstract
Cytokinins are plant hormones with biological functions ranging from coordination of plant growth and development to the regulation of senescence. A series of 2-chloro-N(6)-(halogenobenzylamino)purine ribosides was prepared and tested for cytokinin activity in detached wheat leaf senescence, tobacco callus and Amaranthus bioassays. The synthetic compounds showed significant activity, especially in delaying senescence in detached wheat leaves. They were also tested in bacterial receptor bioassays using both monocot and dicot members of the cytokinin receptor family. Most of the derivatives did not trigger cytokinin signaling via the AHK3 and AHK4 receptors from Arabidopsis thaliana in the bacterial assay, but some of them specifically activated the ZmHK1 receptor from Zea mays and were also more active than the aromatic cytokinin BAP in an ARR5::GUS cytokinin bioassay using transgenic Arabidopsis plants. Whole transcript expression analysis was performed using an Arabidopsis model to gather information about the reprogramming of gene transcription when senescent leaves were treated with selected C2-substituted aromatic cytokinin ribosides. Genome-wide expression profiling revealed that the synthetic halogenated derivatives induced the expression of genes related to cytokinin signaling and metabolism. They also prompted both up- and down-regulation of a unique combination of genes coding for components of the photosystem II (PSII) reaction center, light-harvesting complex II (LHCII), and the oxygen-evolving complex, as well as several stress factors responsible for regulating photosynthesis and chlorophyll degradation. Chlorophyll content and fluorescence analyses demonstrated that treatment with the halogenated derivatives increased the efficiency of PSII photochemistry and the abundance of LHCII relative to DMSO- and BAP-treated controls. These findings demonstrate that it is possible to manipulate and fine-tune leaf longevity using synthetic aromatic cytokinin analogs.
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Affiliation(s)
- Hana Vylíčilová
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Chemical Biology and Genetics, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc CZ-78371, Czech Republic
| | - Alexandra Husičková
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Biophysics, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc CZ-78371, Czech Republic
| | - Lukáš Spíchal
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Chemical Biology and Genetics, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc CZ-78371, Czech Republic
| | - Josef Srovnal
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University and University Hospital in Olomouc, Hněvotínská 5, CZ-77900 Olomouc, Czech Republic
| | - Karel Doležal
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Chemical Biology and Genetics, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc CZ-78371, Czech Republic
| | - Ondřej Plíhal
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Molecular Biology, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc CZ-78371, Czech Republic.
| | - Lucie Plíhalová
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Chemical Biology and Genetics, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc CZ-78371, Czech Republic
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23
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Jiskrová E, Novák O, Pospíšilová H, Holubová K, Karády M, Galuszka P, Robert S, Frébort I. Extra- and intracellular distribution of cytokinins in the leaves of monocots and dicots. N Biotechnol 2016; 33:735-742. [PMID: 26777983 DOI: 10.1016/j.nbt.2015.12.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 12/13/2015] [Accepted: 12/16/2015] [Indexed: 10/22/2022]
Abstract
The plant hormones cytokinins are a convenient target of genetic manipulations that bring benefits in biotechnological applications. The present work demonstrates the importance of the subcellular compartmentalization of cytokinins on the model dicot plant Arabidopsis thaliana and monocot crop Hordeum vulgare. The method of protoplast and vacuole isolation combined with precise cytokinin analysis and recovery assay of a vacuolar marker protein were used to quantify the contents of individual cytokinin forms in the leaf extracellular space, cell interior and vacuole. The data obtained for wild type plants and in each case a specific mutant line allow comparing the effect of genetic manipulations on the hormone distribution and homeostatic balance of cytokinins in the modified plants.
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Affiliation(s)
- Eva Jiskrová
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc CZ-78371, Czech Republic
| | - Ondřej Novák
- Department of Metabolomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany AS CR, Šlechtitelů 27, Olomouc CZ-78371, Czech Republic
| | - Hana Pospíšilová
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc CZ-78371, Czech Republic
| | - Katarína Holubová
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc CZ-78371, Czech Republic
| | - Michal Karády
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc CZ-78371, Czech Republic; Umeå Plant Science Center, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå SE-90183, Sweden
| | - Petr Galuszka
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc CZ-78371, Czech Republic
| | - Stéphanie Robert
- Umeå Plant Science Center, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå SE-90183, Sweden
| | - Ivo Frébort
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc CZ-78371, Czech Republic.
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24
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Pospíšilová H, Jiskrová E, Vojta P, Mrízová K, Kokáš F, Čudejková MM, Bergougnoux V, Plíhal O, Klimešová J, Novák O, Dzurová L, Frébort I, Galuszka P. Transgenic barley overexpressing a cytokinin dehydrogenase gene shows greater tolerance to drought stress. N Biotechnol 2016; 33:692-705. [PMID: 26773738 DOI: 10.1016/j.nbt.2015.12.005] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 12/07/2015] [Accepted: 12/08/2015] [Indexed: 01/10/2023]
Abstract
Together with auxins, cytokinins are the main plant hormones involved in many different physiological processes. Given this knowledge, cytokinin levels can be manipulated by genetic modification in order to improve agronomic parameters of cereals in relation to, for example, morphology, yield, and tolerance to various stresses. The barley (Hordeum vulgare) cultivar Golden Promise was transformed using the cytokinin dehydrogenase 1 gene from Arabidopsis thaliana (AtCKX1) under the control of mild root-specific β-glucosidase promoter from maize. Increased cytokinin degradation activity was observed positively to affect the number and length of lateral roots. The impact on morphology depended upon the recombinant protein's subcellular compartmentation. While assumed cytosolic and vacuolar targeting of AtCKX1 had negligible effect on shoot growth, secretion of AtCKX1 protein to the apoplast had a negative effect on development of the aerial part and yield. Upon the application of severe drought stress, all transgenic genotypes maintained higher water content and showed better growth and yield parameters during revitalization. Higher tolerance to drought stress was most caused by altered root morphology resulting in better dehydration avoidance.
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Affiliation(s)
- Hana Pospíšilová
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Eva Jiskrová
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Petr Vojta
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic; Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, Hněvotínská 1333/5, 779 00 Olomouc, Czech Republic
| | - Katarína Mrízová
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Filip Kokáš
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Mária Majeská Čudejková
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Veronique Bergougnoux
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Ondřej Plíhal
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Jana Klimešová
- Department of Crop Science, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic
| | - Ondřej Novák
- Department of Metabolomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany AS CR, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Lenka Dzurová
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Ivo Frébort
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Petr Galuszka
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic.
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25
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Aremu AO, Stirk WA, Masondo NA, Plačková L, Novák O, Pěnčík A, Zatloukal M, Nisler J, Spíchal L, Doležal K, Finnie JF, Van Staden J. Dissecting the role of two cytokinin analogues (INCYDE and PI-55) on in vitro organogenesis, phytohormone accumulation, phytochemical content and antioxidant activity. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 238:81-94. [PMID: 26259177 DOI: 10.1016/j.plantsci.2015.05.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 05/13/2015] [Accepted: 05/28/2015] [Indexed: 05/11/2023]
Abstract
There is a continuous search for new chemical entities to expand the collection of suitable compounds to increase the efficiency of micropropagation protocols. Two cytokinin (CK) analogues, 2-chloro-6-(3-methoxyphenyl)aminopurine (INCYDE) and CK antagonist 6-(2-hydroxy-3-methylbenzylamino)purine (PI-55) were used as a tool to elucidate the auxin-CK crosstalk under in vitro conditions in the medicinally important plant, Eucomis autumnalis subspecies autumnalis. These compounds were tested at 0.01, 0.1 and 10 μM alone as well as in combination with benzyladenine (BA) and naphthaleneacetic acid (NAA). The organogenesis, phytohormone content, phytochemical and antioxidant response in 10 week-old-in vitro regenerated E. autumnalis subspecies autumnalis was evaluated. INCYDE generally favoured shoot regeneration while the effect of PI-55 was more evident in root proliferation. Overall, INCYDE promoted the accumulation of higher concentrations and varieties of endogenous CK relative to the PI-55 treatments. In contrast, higher concentration of indole-3-acetic acid and 2-oxindole-3-acetic acid were generally observed in PI-55-supplemented cultures when compared to plantlets derived from INCYDE. Both CK analogues (individually and in-conjunction with exogenously applied PGRs) significantly influenced the phytochemicals and consequently the antioxidant potential of the in vitro regenerants. These results provided insight on how to alleviate root inhibition, a problem which causes considerable loss of several elite species during micropropagation.
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Affiliation(s)
- Adeyemi O Aremu
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg Campus, P/Bag X01, Scottsville 3209, South Africa
| | - Wendy A Stirk
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg Campus, P/Bag X01, Scottsville 3209, South Africa
| | - Nqobile A Masondo
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg Campus, P/Bag X01, Scottsville 3209, South Africa
| | - Lenka Plačková
- Laboratory of Growth Regulators & Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University & Institute of Experimental Botany ASCR, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic
| | - Ondřej Novák
- Laboratory of Growth Regulators & Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University & Institute of Experimental Botany ASCR, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic
| | - Aleš Pěnčík
- Laboratory of Growth Regulators & Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University & Institute of Experimental Botany ASCR, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic
| | - Marek Zatloukal
- Laboratory of Growth Regulators & Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University & Institute of Experimental Botany ASCR, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic
| | - Jaroslav Nisler
- Laboratory of Growth Regulators & Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University & Institute of Experimental Botany ASCR, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic
| | - Lukáš Spíchal
- Laboratory of Growth Regulators & Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University & Institute of Experimental Botany ASCR, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic
| | - Karel Doležal
- Laboratory of Growth Regulators & Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University & Institute of Experimental Botany ASCR, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic
| | - Jeffrey F Finnie
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg Campus, P/Bag X01, Scottsville 3209, South Africa
| | - Johannes Van Staden
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg Campus, P/Bag X01, Scottsville 3209, South Africa.
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Hinsch J, Vrabka J, Oeser B, Novák O, Galuszka P, Tudzynski P. De novo biosynthesis of cytokinins in the biotrophic fungus Claviceps purpurea. Environ Microbiol 2015; 17:2935-51. [PMID: 25753486 DOI: 10.1111/1462-2920.12838] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 02/28/2015] [Indexed: 01/08/2023]
Abstract
Disease symptoms of some phytopathogenic fungi are associated with changes in cytokinin (CK) levels. Here, we show that the CK profile of ergot-infected rye plants is also altered, although no pronounced changes occur in the expression of the host plant's CK biosynthesis genes. Instead, we demonstrate a clearly different mechanism: we report on the first fungal de novo CK biosynthesis genes, prove their functions and constitute a biosynthetic pathway. The ergot fungus Claviceps purpurea produces substantial quantities of CKs in culture and, like plants, expresses enzymes containing the isopentenyltransferase and lonely guy domains necessary for de novo isopentenyladenine production. Uniquely, two of these domains are combined in one bifunctional enzyme, CpIPT-LOG, depicting a novel and potent mechanism for CK production. The fungus also forms trans-zeatin, a reaction catalysed by a CK-specific cytochrome P450 monooxygenase, which is encoded by cpp450 forming a small cluster with cpipt-log. Deletion of cpipt-log and cpp450 did not affect virulence of the fungus, but Δcpp450 mutants exhibit a hyper-sporulating phenotype, implying that CKs are environmental factors influencing fungal development.
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Affiliation(s)
- Janine Hinsch
- Institute of Plant Biology and Biotechnology, Westfälische Wilhelms-University Münster, Schlossplatz 8, 48143, Münster, Germany
| | - Josef Vrabka
- Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University & Institute of Experimental Botany AS CR, Šlechtitelů 11, 78371, Olomouc, Czech Republic
| | - Birgitt Oeser
- Institute of Plant Biology and Biotechnology, Westfälische Wilhelms-University Münster, Schlossplatz 8, 48143, Münster, Germany
| | - Ondřej Novák
- Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University & Institute of Experimental Botany AS CR, Šlechtitelů 11, 78371, Olomouc, Czech Republic
| | - Petr Galuszka
- Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University & Institute of Experimental Botany AS CR, Šlechtitelů 11, 78371, Olomouc, Czech Republic
| | - Paul Tudzynski
- Institute of Plant Biology and Biotechnology, Westfälische Wilhelms-University Münster, Schlossplatz 8, 48143, Münster, Germany
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Aremu AO, Plačková L, Bairu MW, Novák O, Szüčová L, Doležal K, Finnie JF, Van Staden J. Endogenous cytokinin profiles of tissue-cultured and acclimatized 'Williams' bananas subjected to different aromatic cytokinin treatments. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2014; 214:88-98. [PMID: 24268166 DOI: 10.1016/j.plantsci.2013.09.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 09/24/2013] [Accepted: 09/25/2013] [Indexed: 06/02/2023]
Abstract
Endogenous cytokinin (CK) levels of in vitro-cultured and greenhouse-acclimatized 'Williams' bananas treated with six aromatic CKs were quantified using UPLC-MS/MS. The underground parts had higher endogenous CK levels than the aerial parts. Control plantlets had more isoprenoid CKs while the aromatic-type CKs were predominant in all other regenerants. Following acclimatization of the control and 10 μM CK regenerants, there was a rapid decline in both isoprenoid and aromatic CK in the greenhouse-grown plants. Apart from the control and 6-(3-Methoxybenzylamino)-9-tetrahydropyran-2-ylpurine (MemTTHP) treatment with higher level of isoprenoid CK, aromatic CK remain the predominant CK-type across all CK treatments. The most abundant CK forms were meta-topolin (mT) and benzyladenine (BA) in the micropropagated and acclimatized plants, respectively. Micropropagated plantlets had cis-Zeatin (cZ) as the major isoprenoid CK-type which was in turn replaced by isopentenyladenine (iP) upon acclimatization. On a structural and functional basis, 9-glucoside, a deactivation/detoxicification product was the most abundant and mainly located in the underground parts (micropropagation and acclimatization). The results establish the wide variation in metabolic products of the tested aromatic CKs during micropropagation and acclimatization. The findings are discussed with the possible physiological roles of the various CK constituents on the growth and development of banana plants.
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Affiliation(s)
- Adeyemi O Aremu
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa
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Fonseca S, Rosado A, Vaughan-Hirsch J, Bishopp A, Chini A. Molecular locks and keys: the role of small molecules in phytohormone research. FRONTIERS IN PLANT SCIENCE 2014; 5:709. [PMID: 25566283 PMCID: PMC4269113 DOI: 10.3389/fpls.2014.00709] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 11/26/2014] [Indexed: 05/03/2023]
Abstract
Plant adaptation, growth and development rely on the integration of many environmental and endogenous signals that collectively determine the overall plant phenotypic plasticity. Plant signaling molecules, also known as phytohormones, are fundamental to this process. These molecules act at low concentrations and regulate multiple aspects of plant fitness and development via complex signaling networks. By its nature, phytohormone research lies at the interface between chemistry and biology. Classically, the scientific community has always used synthetic phytohormones and analogs to study hormone functions and responses. However, recent advances in synthetic and combinational chemistry, have allowed a new field, plant chemical biology, to emerge and this has provided a powerful tool with which to study phytohormone function. Plant chemical biology is helping to address some of the most enduring questions in phytohormone research such as: Are there still undiscovered plant hormones? How can we identify novel signaling molecules? How can plants activate specific hormone responses in a tissue-specific manner? How can we modulate hormone responses in one developmental context without inducing detrimental effects on other processes? The chemical genomics approaches rely on the identification of small molecules modulating different biological processes and have recently identified active forms of plant hormones and molecules regulating many aspects of hormone synthesis, transport and response. We envision that the field of chemical genomics will continue to provide novel molecules able to elucidate specific aspects of hormone-mediated mechanisms. In addition, compounds blocking specific responses could uncover how complex biological responses are regulated. As we gain information about such compounds we can design small alterations to the chemical structure to further alter specificity, enhance affinity or modulate the activity of these compounds.
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Affiliation(s)
- Sandra Fonseca
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología- Consejo Superior de Investigaciones CientíficasMadrid, Spain
| | - Abel Rosado
- The Botany Department, University of British ColumbiaVancouver, BC, Canada
| | - John Vaughan-Hirsch
- Centre for Plant Integrative Biology, University of NottinghamNottingham, UK
| | - Anthony Bishopp
- Centre for Plant Integrative Biology, University of NottinghamNottingham, UK
| | - Andrea Chini
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología- Consejo Superior de Investigaciones CientíficasMadrid, Spain
- *Correspondence: Andrea Chini, Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología- Consejo Superior de Investigaciones Científicas, Campus Universidad Autónoma, C/ Darwin 3, 28049 Madrid, Spain e-mail:
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Mrízová K, Jiskrová E, Vyroubalová Š, Novák O, Ohnoutková L, Pospíšilová H, Frébort I, Harwood WA, Galuszka P. Overexpression of cytokinin dehydrogenase genes in barley (Hordeum vulgare cv. Golden Promise) fundamentally affects morphology and fertility. PLoS One 2013; 8:e79029. [PMID: 24260147 PMCID: PMC3829838 DOI: 10.1371/journal.pone.0079029] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 09/17/2013] [Indexed: 01/07/2023] Open
Abstract
Barley is one of the most important cereal crops grown worldwide. It has numerous applications, but its utility could potentially be extended by genetically manipulating its hormonal balances. To explore some of this potential we identified gene families of cytokinin dehydrogenases (CKX) and isopentenyl transferases, enzymes that respectively irreversibly degrade and synthesize cytokinin (CK) plant hormones, in the raw sequenced barley genome. We then examined their spatial and temporal expression patterns by immunostaining and qPCR. Two CKX-specific antibodies, anti-HvCKX1 and anti-HvCKX9, predominantly detect proteins in the aleurone layer of maturing grains and leaf vasculature, respectively. In addition, two selected CKX genes were used for stable, Agrobacterium tumefaciens-mediated transformation of the barley cultivar Golden Promise. The results show that constitutive overexpression of CKX causes morphological changes in barley plants and prevents their transition to flowering. In all independent transgenic lines roots proliferated more rapidly and root-to-shoot ratios were higher than in wild-type plants. Only one transgenic line, overexpressing CKX under the control of a promoter from a phosphate transporter gene, which is expressed more strongly in root tissue than in aerial parts, yielded progeny. Analysis of several T1-generation plants indicates that plants tend to compensate for effects of the transgene and restore CK homeostasis later during development. Depleted CK levels during early phases of development are restored by down-regulation of endogenous CKX genes and reinforced de novo biosynthesis of CKs.
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Affiliation(s)
- Katarína Mrízová
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, Olomouc, Czech Republic
| | - Eva Jiskrová
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, Olomouc, Czech Republic
| | - Šárka Vyroubalová
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, Olomouc, Czech Republic
| | - Ondřej Novák
- Laboratory of Growth Regulatory, Palacký University and Institute of Experimental Botany, Olomouc, Czech Republic
| | - Ludmila Ohnoutková
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, Olomouc, Czech Republic
| | - Hana Pospíšilová
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, Olomouc, Czech Republic
| | - Ivo Frébort
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, Olomouc, Czech Republic
| | - Wendy A. Harwood
- Department of Crop Genetics, John Innes Centre, Norwich, United Kingdom
| | - Petr Galuszka
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, Olomouc, Czech Republic
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Plíhal O, Szüčová L, Galuszka P. N9-substituted aromatic cytokinins with negligible side effects on root development are an emerging tool for in vitro culturing. PLANT SIGNALING & BEHAVIOR 2013; 8:e24392. [PMID: 23603971 PMCID: PMC3909062 DOI: 10.4161/psb.24392] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Natural cytokinins as well as the majority of their synthetic derivatives show negative effects on root growth and development. Changes in morphology, primarily linked to the inhibition of the cell division in the meristematic zone, are manifested as thickening and shortening of the primary root and impaired lateral root branching. Rational design of cytokinin derivatives can partially overcome these drawbacks and reduce the negative effects. Using our database of cytokinin derivatives, we selected several aromatic cytokinin analogs with modifications at the N9 atom of the adenine moiety. We found that tetrahydropyranyl and tetrahydrofuranyl substitutions at the N9 atom led to enhanced acropetal transport of the modified cytokinin, and both derivatives also showed weak anticytokinin activity. Consequently, changes in the distribution of the active cytokinin pool together with gradual metabolic conversion of the modified cytokinin to its free form prevent root growth inhibition that limits cytokinin utilization in micropropagation techniques.
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