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Yu W, Luo L, Qi X, Cao Y, An J, Xie Z, Hu T, Yang P. Insights into the Impact of Trans-Zeatin Overproduction-Engineered Sinorhizobium meliloti on Alfalfa ( Medicago sativa L.) Tolerance to Drought Stress. J Agric Food Chem 2024; 72:8650-8663. [PMID: 38564678 DOI: 10.1021/acs.jafc.4c00115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Plant growth-promoting rhizobacteria have been shown to enhance plant tolerance to drought stress through various mechanisms. However, there is limited research on improving drought resistance in alfalfa by genetically modifying PGPR to produce increased levels of cytokinins. Herein, we employed synthetic biology approaches to engineer two novel strains of Sinorhizobium meliloti capable of overproducing trans-Zeatin and investigated their potential in enhancing drought tolerance in alfalfa. Our results demonstrate that alfalfa plants inoculated with these engineered S. meliloti strains exhibited reduced wilting and yellowing while maintaining higher relative water content under drought conditions. The engineered S. meliloti-induced tZ activated the activity of antioxidant enzymes and the accumulation of osmolytes. Additionally, the increased endogenous tZ content in plants alleviated the impact of drought stress on the alfalfa photosynthetic rate. However, under nondrought conditions, inoculation with the engineered S. meliloti strains had no significant effect on alfalfa biomass and nodule formation.
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Affiliation(s)
- Wenzhe Yu
- College of Grassland Agriculture, Northwest A&F University, Yangling 712100, China
| | - Li Luo
- Shanghai Key Laboratory of Bio-Energy Crops, Shanghai University, Shanghai 200444, China
| | - Xiangyu Qi
- College of Grassland Agriculture, Northwest A&F University, Yangling 712100, China
| | - Yuman Cao
- College of Grassland Agriculture, Northwest A&F University, Yangling 712100, China
| | - Jie An
- College of Grassland Agriculture, Northwest A&F University, Yangling 712100, China
| | - Zhiguo Xie
- Shaanxi Academy of Forestry, Xi'an 710082, China
| | - Tianming Hu
- College of Grassland Agriculture, Northwest A&F University, Yangling 712100, China
| | - Peizhi Yang
- College of Grassland Agriculture, Northwest A&F University, Yangling 712100, China
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Fiorillo A, Parmagnani AS, Visconti S, Mannino G, Camoni L, Maffei ME. 14-3-3 Proteins and the Plasma Membrane H +-ATPase Are Involved in Maize ( Zea mays) Magnetic Induction. Plants (Basel) 2023; 12:2887. [PMID: 37571041 PMCID: PMC10421175 DOI: 10.3390/plants12152887] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/01/2023] [Accepted: 08/04/2023] [Indexed: 08/13/2023]
Abstract
The geomagnetic field (GMF) is a natural component of the biosphere, and, during evolution, all organisms experienced its presence while some evolved the ability to perceive magnetic fields (MF). We studied the response of 14-3-3 proteins and the plasma membrane (PM) proton pump H+-ATPase to reduced GMF values by lowering the GMF intensity to a near-null magnetic field (NNMF). Seedling morphology, H+-ATPase activity and content, 14-3-3 protein content, binding to PM and phosphorylation, gene expression, and ROS quantification were assessed in maize (Zea mays) dark-grown seedlings. Phytohormone and melatonin quantification were also assessed by LG-MS/MS. Our results suggest that the GMF regulates the PM H+-ATPase, and that NNMF conditions alter the proton pump activity by reducing the binding of 14-3-3 proteins. This effect was associated with both a reduction in H2O2 and downregulation of genes coding for enzymes involved in ROS production and scavenging, as well as calcium homeostasis. These early events were followed by the downregulation of IAA synthesis and gene expression and the increase in both cytokinin and ABA, which were associated with a reduction in root growth. The expression of the homolog of the MagR gene, ZmISCA2, paralleled that of CRY1, suggesting a possible role of ISCA in maize magnetic induction. Interestingly, melatonin, a widespread molecule present in many kingdoms, was increased by the GMF reduction, suggesting a still unknown role of this molecule in magnetoreception.
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Affiliation(s)
- Anna Fiorillo
- Department of Biology, Tor Vergata University of Rome, Via della Ricerca Scientifica, 00133 Rome, Italy; (A.F.); (S.V.)
| | - Ambra S. Parmagnani
- Department of Life Sciences and Systems Biology, University of Turin, Via Quarello 15/a, 10135 Turin, Italy; (A.S.P.); (G.M.)
| | - Sabina Visconti
- Department of Biology, Tor Vergata University of Rome, Via della Ricerca Scientifica, 00133 Rome, Italy; (A.F.); (S.V.)
| | - Giuseppe Mannino
- Department of Life Sciences and Systems Biology, University of Turin, Via Quarello 15/a, 10135 Turin, Italy; (A.S.P.); (G.M.)
| | - Lorenzo Camoni
- Department of Biology, Tor Vergata University of Rome, Via della Ricerca Scientifica, 00133 Rome, Italy; (A.F.); (S.V.)
| | - Massimo E. Maffei
- Department of Life Sciences and Systems Biology, University of Turin, Via Quarello 15/a, 10135 Turin, Italy; (A.S.P.); (G.M.)
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Chai L, Wang H, Yu H, Pang E, Lu T, Li Y, Jiang W, Li Q. Girdling promotes tomato fruit enlargement by enhancing fruit sink strength and triggering cytokinin accumulation. Front Plant Sci 2023; 14:1174403. [PMID: 37396637 PMCID: PMC10312241 DOI: 10.3389/fpls.2023.1174403] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Accepted: 05/24/2023] [Indexed: 07/04/2023]
Abstract
Girdling is a horticultural technique that enhances fruit size by allocating more carbohydrates to fruits, yet its underlying mechanisms are not fully understood. In this study, girdling was applied to the main stems of tomato plants 14 days after anthesis. Following girdling, there was a significant increase in fruit volume, dry weight, and starch accumulation. Interestingly, although sucrose transport to the fruit increased, the fruit's sucrose concentration decreased. Girdling also led to an increase in the activities of enzymes involved in sucrose hydrolysis and AGPase, and to an upregulation in the expression of key genes related to sugar transport and utilization. Moreover, the assay of carboxyfluorescein (CF) signal in detached fruit indicated that girdled fruits exhibited a greater ability to take up carbohydrates. These results indicate that girdling improves sucrose unloading and sugar utilization in fruit, thereby enhancing fruit sink strength. In addition, girdling induced cytokinin (CK) accumulation, promoted cell division in the fruit, and upregulated the expression of genes related to CK synthesis and activation. Furthermore, the results of a sucrose injection experiment suggested that increased sucrose import induced CK accumulation in the fruit. This study sheds light on the mechanisms by which girdling promotes fruit enlargement and provides novel insights into the interaction between sugar import and CK accumulation.
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Affiliation(s)
| | | | | | | | | | | | | | - Qiang Li
- *Correspondence: Qiang Li, ; Weijie Jiang,
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Sakakibara H. Cytokinin biosynthesis and transport for systemic nitrogen signaling. Plant J 2021; 105:421-430. [PMID: 33015901 DOI: 10.1111/tpj.15011] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 09/20/2020] [Accepted: 09/23/2020] [Indexed: 06/11/2023]
Abstract
The plasticity of growth and development in response to environmental changes is one of the essential aspects of plant behavior. Cytokinins play an important role as signaling molecules in the long-distance communication between organs in systemic growth regulation in response to nitrogen. The spatial distribution of the expression sites of cytokinin biosynthesis genes leads to structural differences in the molecular species transported through the xylem and phloem, giving root-borne trans-hydroxylated cytokinins, namely trans-zeatin (tZ) type, a specialized efficacy in regulating shoot growth. Furthermore, root-to-shoot translocation via the xylem, tZ, and its precursor, the tZ riboside, controls different sets of shoot growth traits to fine-tune shoot growth in response to nitrogen availability. In addition to nitrogen, photosynthetically generated sugars positively regulate de novo cytokinin biosynthesis in the roots, and contribute to plant growth under elevated CO2 conditions. In shoot-to-root signaling, cytokinins also play a role in the regulation of nutrient acquisition and root system growth in cooperation with other types of signaling molecules, such as C-TERMINALLY ENCODED PEPTIDE DOWNSTREAMs. As cytokinin is a key regulator for the maintenance of shoot apical meristem, deepening our understanding of the regulatory mechanisms of cytokinin biosynthesis and transport in response to nitrogen is important not only for basic comprehension of plant growth, but also to ensure the stability of agricultural production.
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Affiliation(s)
- Hitoshi Sakakibara
- Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, 464-8601, Japan
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Pokorná E, Hluska T, Galuszka P, Hallmark HT, Dobrev PI, Záveská Drábková L, Filipi T, Holubová K, Plíhal O, Rashotte AM, Filepová R, Malbeck J, Novák O, Spíchal L, Brzobohatý B, Mazura P, Zahajská L, Motyka V. Cytokinin N-glucosides: Occurrence, Metabolism and Biological Activities in Plants. Biomolecules 2020; 11:E24. [PMID: 33379369 DOI: 10.3390/biom11010024] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Frank M, Cortleven A, Novák O, Schmülling T. Root-derived trans-zeatin cytokinin protects Arabidopsis plants against photoperiod stress. Plant Cell Environ 2020; 43:2637-2649. [PMID: 32716064 DOI: 10.1111/pce.13860] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 07/15/2020] [Indexed: 05/20/2023]
Abstract
Recently, a novel type of abiotic stress caused by a prolongation of the light period-coined photoperiod stress-has been described in Arabidopsis. During the night after the prolongation of the light period, stress and cell death marker genes are induced. The next day, strongly stressed plants display a reduced photosynthetic efficiency and leaf cells eventually enter programmed cell death. The phytohormone cytokinin (CK) acts as a negative regulator of this photoperiod stress syndrome. In this study, we show that Arabidopsis wild-type plants increase the CK concentration in response to photoperiod stress. Analysis of cytokinin synthesis and transport mutants revealed that root-derived trans-zeatin (tZ)-type CKs protect against photoperiod stress. The CK signalling proteins ARABIDOPSIS HISTIDINE PHOSPHOTRANSFER PROTEIN 2 (AHP2), AHP3 and AHP5 and transcription factors ARABIDOPSIS RESPONSE REGULATOR 2 (ARR2), ARR10 and ARR12 are required for the protective activity of CK. Analysis of higher order B-type arr mutants suggested that a complex regulatory circuit exists in which the loss of ARR10 or ARR12 can rescue the arr2 phenotype. Together the results revealed the role of root-derived CK acting in the shoot through the two-component signalling system to protect from the negative consequences of strong photoperiod stress.
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Affiliation(s)
- Manuel Frank
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Berlin, Germany
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Anne Cortleven
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Berlin, Germany
| | - Ondřej Novák
- Laboratory of Growth Regulators, Faculty of Science, Palacký University & Institute of Experimental Botany, The Czech Academy of Sciences, Olomouc, Czech Republic
| | - Thomas Schmülling
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Berlin, Germany
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Liu CJ, Zhao Y, Zhang K. Cytokinin Transporters: Multisite Players in Cytokinin Homeostasis and Signal Distribution. Front Plant Sci 2019; 10:693. [PMID: 31214217 PMCID: PMC6555093 DOI: 10.3389/fpls.2019.00693] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 05/08/2019] [Indexed: 05/04/2023]
Abstract
Cytokinins (CKs) are a group of mobile adenine derivatives that act as chemical signals regulating a variety of biological processes implicated in plant development and stress responses. Their synthesis, homeostasis, and signaling perception evoke complicated intracellular traffic, intercellular movement, and in short- and long-distance translocation. Over nearly two decades, subsets of membrane transporters have been recognized and implicated in the transport of CKs as well as the related adenylates. In this review, we aim to recapitulate the key progresses in exploration of the transporter proteins involved in cytokinin traffic and translocation, discuss their functional implications in the cytokinin-mediated paracrine and long-distance communication, and highlight some knowledge gaps and open issues toward comprehensively understanding the molecular mechanism of membrane transporters in controlling spatiotemporal distribution of cytokinin species.
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Affiliation(s)
- Chang-Jun Liu
- Department of Biology, Brookhaven National Laboratory, Upton, NY, United States
| | - Yunjun Zhao
- Department of Biology, Brookhaven National Laboratory, Upton, NY, United States
| | - Kewei Zhang
- Department of Biology, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, China
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Žižková E, Kubeš M, Dobrev PI, Přibyl P, Šimura J, Zahajská L, Záveská Drábková L, Novák O, Motyka V. Control of cytokinin and auxin homeostasis in cyanobacteria and algae. Ann Bot 2017; 119:151-166. [PMID: 27707748 PMCID: PMC5218379 DOI: 10.1093/aob/mcw194] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 07/18/2016] [Accepted: 08/11/2016] [Indexed: 05/10/2023]
Abstract
BACKGROUND AND AIMS The metabolism of cytokinins (CKs) and auxins in vascular plants is relatively well understood, but data concerning their metabolic pathways in non-vascular plants are still rather rare. With the aim of filling this gap, 20 representatives of taxonomically major lineages of cyanobacteria and algae from Cyanophyceae, Xanthophyceae, Eustigmatophyceae, Porphyridiophyceae, Chlorophyceae, Ulvophyceae, Trebouxiophyceae, Zygnematophyceae and Klebsormidiophyceae were analysed for endogenous profiles of CKs and auxins and some of them were used for studies of the metabolic fate of exogenously applied radiolabelled CK, [3H]trans-zeatin (transZ) and auxin ([3H]indole-3-acetic acid (IAA)), and the dynamics of endogenous CK and auxin pools during algal growth and cell division. METHODS Quantification of phytohormone levels was performed by high-performance or ultrahigh-performance liquid chromatography-electrospray tandem mass spectrometry (HPLC-MS/MS, UHPLC-MS/MS). The dynamics of exogenously applied [3H]transZ and [3H]IAA in cell cultures were monitored by HPLC with on-line radioactivity detection. KEY RESULTS The comprehensive screen of selected cyanobacteria and algae for endogenous CKs revealed a predominance of bioactive and phosphate CK forms while O- and N-glucosides evidently did not contribute greatly to the total CK pool. The abundance of cis-zeatin-type CKs and occurrence of CK 2-methylthio derivatives pointed to the tRNA pathway as a substantial source of CKs. The importance of the tRNA biosynthetic pathway was proved by the detection of tRNA-bound CKs during the course of Scenedesmus obliquus growth. Among auxins, free IAA and its oxidation catabolite 2-oxindole-3-acetic acid represented the prevailing endogenous forms. After treatment with [3H]IAA, IAA-aspartate and indole-3-acetyl-1-glucosyl ester were detected as major auxin metabolites. Moreover, different dynamics of endogenous CKs and auxin profiles during S. obliquus culture clearly demonstrated diverse roles of both phytohormones in algal growth and cell division. CONCLUSIONS Our data suggest the existence and functioning of a complex network of metabolic pathways and activity control of CKs and auxins in cyanobacteria and algae that apparently differ from those in vascular plants.
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Affiliation(s)
- Eva Žižková
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany CAS, Rozvojová 263, CZ-165 02 Prague 6, Czech Republic
| | - Martin Kubeš
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany CAS, Rozvojová 263, CZ-165 02 Prague 6, Czech Republic
- 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
| | - Petre I Dobrev
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany CAS, Rozvojová 263, CZ-165 02 Prague 6, Czech Republic
| | - Pavel Přibyl
- Centre for Phycology and Biorefinery Research Centre of Competence, Institute of Botany CAS, Dukelská 135, CZ-379 82 Třeboň, Czech Republic
| | - Jan Šimura
- 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
| | - Lenka Zahajská
- Isotope Laboratory, Institute of Experimental Botany CAS, Vídeňská 1083, CZ-142 20 Prague 4, Czech Republic
| | - Lenka Záveská Drábková
- Department of Taxonomy and Biosystematics, Institute of Botany CAS, Zámek 1, CZ-252 43 Průhonice, Czech Republic
| | - Ondřej Novák
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science of Palacký University and Institute of Experimental Botany CAS, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic
| | - Václav Motyka
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany CAS, Rozvojová 263, CZ-165 02 Prague 6, Czech Republic
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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 Sci 2016; 247:127-37. [PMID: 27095406 DOI: 10.1016/j.plantsci.2016.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 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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Hernández I, Miret JA, Van Der Kelen K, Rombaut D, Van Breusegem F, Munné-Bosch S. Zeatin modulates flower bud development and tocopherol levels in Cistus albidus (L.) plants as they age. Plant Biol (Stuttg) 2015; 17:90-96. [PMID: 24943106 DOI: 10.1111/plb.12207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 04/12/2014] [Indexed: 06/03/2023]
Abstract
In a previous study we showed that Cistus albidus (L.) experiences an age-dependent decay in flower vigour correlated with a decline in trans-zeatin (tZ) levels. In the present study we aimed to establish a causal relationship between these two phenomena. Exogenous tZ applied to plants grown under semi-controlled conditions did not rescue flower vigour; however, it accelerated flower development, but only in younger individuals. Older plants showed lower tocopherol levels in flower buds, which were restored by exogenous tZ, suggesting that a loss of antioxidant defences may underlie the age-dependent decay in flower vigour. We conclude that declining tZ levels may not be directly responsible for the age-associated loss of floral vigour; that tZ modulates the speed of flower development as plants age; and that flower buds alter their sensitivity to tZ as plants age.
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Affiliation(s)
- I Hernández
- Departament de Biologia Vegetal, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
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Zalabák D, Galuszka P, Mrízová K, Podlešáková K, Gu R, Frébortová J. Biochemical characterization of the maize cytokinin dehydrogenase family and cytokinin profiling in developing maize plantlets in relation to the expression of cytokinin dehydrogenase genes. Plant Physiol Biochem 2014; 74:283-93. [PMID: 24333683 DOI: 10.1016/j.plaphy.2013.11.020] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 11/19/2013] [Indexed: 05/18/2023]
Abstract
The cytokinin dehydrogenases (CKX; EC 1.5.99.12) are a protein family that maintains the endogenous levels of cytokinins in plants by catalyzing their oxidative degradation. The CKX family in maize (Zea mays L.) has thirteen members, only two of which--ZmCKX1 and ZmCKX10--have previously been characterized in detail. In this study, nine further maize CKX isoforms were heterologously expressed in Escherichia coli, purified by affinity and ion-exchange chromatography and biochemically characterized. ZmCKX6 and ZmCKX9 could only be expressed successfully after the removal of putative sequence-specific vacuolar sorting signals (LLPT and LPTS, respectively), suggesting that these proteins are localized to the vacuole. Substrate specificity analyses revealed that the CKX isoforms can be grouped into two subfamilies: members of the first strongly prefer cytokinin free bases while members of the second degrade a broad range of substrates. The most active isoform was found to be ZmCKX1. One of the studied isoforms, ZmCKX6, seemed to encode a nonfunctional enzyme due to a mutation in a conserved HFG protein domain at the C-terminus. Site-directed mutagenesis experiments revealed that this domain is essential for CKX activity. The roles of the maize CKX enzymes in the development of maize seedlings during the two weeks immediately after radicle emergence were also investigated. It appears that ZmCKX1 is a key regulator of active cytokinin levels in developing maize roots. However, the expression of individual CKX isoforms in the shoots varied and none of them seemed to have strong effects on the cytokinin pool.
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Affiliation(s)
- David Zalabák
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Molecular Biology, Šlechtitelů 11, Olomouc 783 71, Czech Republic.
| | - Petr Galuszka
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Molecular Biology, Šlechtitelů 11, Olomouc 783 71, Czech Republic.
| | - Katarina Mrízová
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Molecular Biology, Šlechtitelů 11, Olomouc 783 71, Czech Republic.
| | - Kateřina Podlešáková
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Chemical Biology and Genetics, Šlechtitelů 11, Olomouc 783 71, Czech Republic.
| | - Riliang Gu
- Key Lab of Plant Nutrition, MOA, College of Resources and Environmental Science, China Agricultural University, 100193 Beijing, China.
| | - Jitka Frébortová
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Chemical Biology and Genetics, Šlechtitelů 11, Olomouc 783 71, Czech Republic.
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Stirk WA, Bálint P, Tarkowská D, Novák O, Strnad M, Ördög V, van Staden J. Hormone profiles in microalgae: gibberellins and brassinosteroids. Plant Physiol Biochem 2013; 70:348-53. [PMID: 23811778 DOI: 10.1016/j.plaphy.2013.05.037] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 05/28/2013] [Indexed: 05/07/2023]
Abstract
Endogenous gibberellins and brassinosteroids were quantified in 24 axenic microalgae strains from the Chlorophyceae, Trebouxiophyceae, Ulvophyceae and Charophyceae microalgae strains after 4 days in culture. This is the first report of endogenous gibberellins being successfully detected in microalgae. Between 18 and 20 gibberellins were quantified in all strains with concentrations ranging from 342.7 pg mg(-1) DW in Raphidocelis subcapitata MACC 317-4746.1 pg mg(-)(1) DW in Scotiellopsis terrestris MACC 44. Slower growing strains (S. terrestris MACC 44, Gyoerffyana humicola MACC 334, Nautococcus mamillatus MACC 716 and Chlorococcum ellipsoideum MACC 712) exhibited the highest gibberellin contents while lowest levels of gibberellins were found in faster growing strains (R. subcapitata MACC 317 and Coelastrum excentrica MACC 504). In all strains, the active gibberellin detected in the highest concentration was GA6, the predominant intermediates were GA15 and GA53 and the main biosynthetic end products were GA13 and GA51. Gibberellin profiles were similar in all strains except for the presence/absence of GA12 and GA12ald. To date this is the second report of endogenous brassinosteroids in microalgae. Brassinosteroids were detected in all 24 strains with concentrations ranging from 117.3 pg mg(-)(1) DW in R. subcapitata MACC 317-977.8 pg mg(-)(1) DW in Klebsormidium flaccidum MACC 692. Two brassinosteroids, brassinolide and castasterone were determined in all the strains. Generally, brassinolide occurred in higher concentrations than castasterone.
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Affiliation(s)
- W A Stirk
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, P/Bag X01, Scottsville 3209, South Africa.
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