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Ricci A, Polverini E, Bruno S, Dramis L, Ceresini D, Scarano A, Diaz-Sala C. New Insights into the Enhancement of Adventitious Root Formation Using N,N'-Bis(2,3-methylenedioxyphenyl)urea. PLANTS (BASEL, SWITZERLAND) 2023; 12:3610. [PMID: 37896073 PMCID: PMC10610038 DOI: 10.3390/plants12203610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 10/11/2023] [Accepted: 10/13/2023] [Indexed: 10/29/2023]
Abstract
Adventitious rooting is a process of postembryonic organogenesis strongly affected by endogenous and exogenous factors. Although adventitious rooting has been exploited in vegetative propagation programs for many plant species, it is a bottleneck for vegetative multiplication of difficult-to-root species, such as many woody species. The purpose of this research was to understand how N,N'-bis-(2,3-methylenedioxyphenyl)urea could exert its already reported adventitious rooting adjuvant activity, starting from the widely accepted knowledge that adventitious rooting is a hormonally tuned progressive process. Here, by using specific in vitro bioassays, histological analyses, molecular docking simulations and in vitro enzymatic bioassays, we have demonstrated that this urea derivative does not interfere with polar auxin transport; it inhibits cytokinin oxidase/dehydrogenase (CKX); and, possibly, it interacts with the apoplastic portion of the auxin receptor ABP1. As a consequence of this dual binding capacity, the lifespan of endogenous cytokinins could be locally increased and, at the same time, auxin signaling could be favored. This combination of effects could lead to a cell fate transition, which, in turn, could result in increased adventitious rooting.
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Affiliation(s)
- Ada Ricci
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Eugenia Polverini
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, Parco Area delle Scienze 7/A, 43124 Parma, Italy
| | - Stefano Bruno
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy
| | - Lucia Dramis
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Daniela Ceresini
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Antonio Scarano
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy
| | - Carmen Diaz-Sala
- Departamento de Ciencias de la Vida, Universidad de Alcalá, 28871 Alcalá de Henares, Spain
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2
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Wei X, Moreno-Hagelsieb G, Glick BR, Doxey AC. Comparative analysis of adenylate isopentenyl transferase genes in plant growth-promoting bacteria and plant pathogenic bacteria. Heliyon 2023; 9:e13955. [PMID: 36938451 PMCID: PMC10018469 DOI: 10.1016/j.heliyon.2023.e13955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 02/01/2023] [Accepted: 02/06/2023] [Indexed: 03/09/2023] Open
Abstract
Cytokinin is a major phytohormone that has been used in agriculture as a plant-growth stimulating compound since its initial discovery in the 1960s. Isopentenyl transferase (IPT) is a rate-limiting enzyme for cytokinin biosynthesis, which is produced by plants as well as bacteria including both plant pathogenic species and plant growth-promoting bacteria (PGPB). It has been hypothesized that there may be differences in IPT function between plant pathogens and PGPB. However, a comprehensive comparison of IPT genes between plant pathogenic and PGPB species has not been performed. Here, we performed a global comparison of IPT genes across bacteria, analyzing their DNA sequences, codon usage, phyletic distribution, promoter structure and genomic context. We found that adenylate type IPT genes are highly specific to plant-associated bacteria and subdivide into two major clades: clade A, largely composed of proteobacterial plant pathogens; and clade B, largely composed of actinomycete PGPB species. Besides these phylogenetic differences, we identified several genomic features that suggest differences in IPT regulation between pathogens and PGPB. Pathogen-associated IPTs tended to occur in predicted virulence loci, whereas PGPB-associated IPTs tended to co-occur with other genes involved in cytokinin metabolism and degradation. Pathogen-associated IPTs also showed elevated gene copy numbers, significant deviation in codon usage patterns, and extended promoters, suggesting differences in regulation and activity levels. Our results are consistent with the hypothesis that differences in IPT regulation and activity exist between plant pathogens and PGPB, which determine their effect on plant host phenotypes through the control of cytokinin levels.
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Affiliation(s)
- Xin Wei
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | | | - Bernard R. Glick
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Andrew C. Doxey
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
- Corresponding author.
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3
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Sharma A, Prakash S, Chattopadhyay D. Killing two birds with a single stone-genetic manipulation of cytokinin oxidase/dehydrogenase ( CKX) genes for enhancing crop productivity and amelioration of drought stress response. Front Genet 2022; 13:941595. [PMID: 35923693 PMCID: PMC9340367 DOI: 10.3389/fgene.2022.941595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 06/29/2022] [Indexed: 12/02/2022] Open
Abstract
The development of high-yielding, bio-fortified, stress-tolerant crop cultivars is the need of the hour in the wake of increasing global food insecurity, abrupt climate change, and continuous shrinking of resources and landmass suitable for agriculture. The cytokinin group of phytohormones positively regulates seed yield by simultaneous regulation of source capacity (leaf senescence) and sink strength (grain number and size). Cytokinins also regulate root-shoot architecture by promoting shoot growth and inhibiting root growth. Cytokinin oxidase/dehydrogenase (CKX) are the only enzymes that catalyze the irreversible degradation of active cytokinins and thus negatively regulate the endogenous cytokinin levels. Genetic manipulation of CKX genes is the key to improve seed yield and root-shoot architecture through direct manipulation of endogenous cytokinin levels. Downregulation of CKX genes expressed in sink tissues such as inflorescence meristem and developing seeds, through reverse genetics approaches such as RNAi and CRISPR/Cas9 resulted in increased yield marked by increased number and size of grains. On the other hand, root-specific expression of CKX genes resulted in decreased endogenous cytokinin levels in roots which in turn resulted in increased root growth indicated by increased root branching, root biomass, and root-shoot biomass ratio. Enhanced root growth provided enhanced tolerance to drought stress and improved micronutrient uptake efficiency. In this review, we have emphasized the role of CKX as a genetic factor determining yield, micronutrient uptake efficiency, and response to drought stress. We have summarised the efforts made to increase crop productivity and drought stress tolerance in different crop species through genetic manipulation of CKX family genes.
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Identification and Functional Characterization of Apple MdCKX5.2 in Root Development and Abiotic Stress Tolerance. HORTICULTURAE 2022. [DOI: 10.3390/horticulturae8010062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cytokinin oxidase/dehydrogenases (CKXs) are the key enzymes in cytokinin degradation and have been widely studied in model plants. Little is known about apple’s (Malus×domestica) CKX genes. Here, using genome-wide analysis, we identified 10 MdCKX genes in apple. The phylogenetics, chromosome locations, and genome structures were then tested. Expression analysis showed that MdCKX genes had different expression profiles in apple, pointing to the different roles. Meanwhile, relative expression analysis showed that these genes have different expression patterns in response to several exogenous cytokinin factors, including trans-zeatin (ZT), thidiazuron (TDZ), and N6-furfuryladenine (KT). Finally, we introduced the MdCKX5.2 gene into Arabidopsis to evaluate its functions, and the results suggested the transgenic Arabidopsis displayed phenotypes related to promoting primary root and lateral root development, response to exogenous ZT, and conferring to drought and salt tolerant. Taken together, our results provide insights on the possible application of the MdCKX5.2 gene for molecular breeding in apples.
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5
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Frébortová J, Frébort I. Biochemical and Structural Aspects of Cytokinin Biosynthesis and Degradation in Bacteria. Microorganisms 2021; 9:microorganisms9061314. [PMID: 34208724 PMCID: PMC8234997 DOI: 10.3390/microorganisms9061314] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/11/2021] [Accepted: 06/14/2021] [Indexed: 11/16/2022] Open
Abstract
It has been known for quite some time that cytokinins, hormones typical of plants, are also produced and metabolized in bacteria. Most bacteria can only form the tRNA-bound cytokinins, but there are examples of plant-associated bacteria, both pathogenic and beneficial, that actively synthesize cytokinins to interact with their host. Similar to plants, bacteria produce diverse cytokinin metabolites, employing corresponding metabolic pathways. The identification of genes encoding the enzymes involved in cytokinin biosynthesis and metabolism facilitated their detailed characterization based on both classical enzyme assays and structural approaches. This review summarizes the present knowledge on key enzymes involved in cytokinin biosynthesis, modifications, and degradation in bacteria, and discusses their catalytic properties in relation to the presence of specific amino acid residues and protein structure.
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6
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Nisler J, Kopečný D, Pěkná Z, Končitíková R, Koprna R, Murvanidze N, Werbrouck SPO, Havlíček L, De Diego N, Kopečná M, Wimmer Z, Briozzo P, Moréra S, Zalabák D, Spíchal L, Strnad M. Diphenylurea-derived cytokinin oxidase/dehydrogenase inhibitors for biotechnology and agriculture. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:355-370. [PMID: 32945834 DOI: 10.1093/jxb/eraa437] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 09/17/2020] [Indexed: 05/11/2023]
Abstract
Increasing crop productivity is our major challenge if we are to meet global needs for food, fodder and fuel. Controlling the content of the plant hormone cytokinin is a method of improving plant productivity. Cytokinin oxidase/dehydrogenase (CKO/CKX) is a major target in this regard because it degrades cytokinins. Here, we describe the synthesis and biological activities of new CKX inhibitors derived mainly from diphenylurea. They were tested on four CKX isoforms from maize and Arabidopsis, where the best compounds showed IC50 values in the 10-8 M concentration range. The binding mode of the most efficient inhibitors was characterized from high-resolution crystal complexed structures. Although these compounds do not possess intrinsic cytokinin activity, we have demonstrated their tremendous potential for use in the plant tissue culture industry as well as in agriculture. We have identified a key substance, compound 19, which not only increases stress resistance and seed yield in Arabidopsis, but also improves the yield of wheat, barley and rapeseed grains under field conditions. Our findings reveal that modulation of cytokinin levels via CKX inhibition can positively affect plant growth, development and yield, and prove that CKX inhibitors can be an attractive target in plant biotechnology and agriculture.
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Affiliation(s)
- Jaroslav Nisler
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences & Palacký University, Šlechtitelů 27, Olomouc, Czech Republic
- Department of Chemistry of Natural Compounds, Faculty of Food and Biochemical Technology, University of Chemistry and Technology in Prague, Technická 5, Prague, 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, 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, Šlechtitelů 27, Olomouc, Czech Republic
| | - Zuzana Pěkná
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc, Czech Republic
| | - Radka Končitíková
- Department of Protein Biochemistry and Proteomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 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, Olomouc, Czech Republic
| | - Nino Murvanidze
- Department Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Stefaan P O Werbrouck
- Department Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Libor Havlíček
- Isotope Laboratory, Institute of Experimental Botany, The Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic
| | - Nuria De Diego
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc, Czech Republic
| | - Martina Kopečná
- Department of Protein Biochemistry and Proteomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc, Czech Republic
| | - Zdeněk Wimmer
- Department of Chemistry of Natural Compounds, Faculty of Food and Biochemical Technology, University of Chemistry and Technology in Prague, Technická 5, Prague, Czech Republic
- Isotope Laboratory, Institute of Experimental Botany, The Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic
| | - Pierre Briozzo
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Route de Saint-Cyr, Versailles, France
| | - Solange Moréra
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - David Zalabák
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc, Czech Republic
| | - Lukáš Spíchal
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc, Czech Republic
| | - Miroslav Strnad
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences & Palacký University, Šlechtitelů 27, Olomouc, Czech Republic
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Nguyen HN, Kambhampati S, Kisiala A, Seegobin M, Emery RJN. The soybean ( Glycine max L.) cytokinin oxidase/dehydrogenase multigene family; Identification of natural variations for altered cytokinin content and seed yield. PLANT DIRECT 2021; 5:e00308. [PMID: 33644633 PMCID: PMC7887454 DOI: 10.1002/pld3.308] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 01/15/2021] [Accepted: 01/18/2021] [Indexed: 05/11/2023]
Abstract
Cytokinins (CKs) play a fundamental role in regulating dynamics of organ source/sink relationships during plant development, including flowering and seed formation stages. As a result, CKs are key drivers of seed yield. The cytokinin oxidase/dehydrogenase (CKX) is one of the critical enzymes responsible for regulating plant CK levels by causing their irreversible degradation. Variation of CKX activity is significantly correlated with seed yield in many crop species while in soybean (Glycine max L.), the possible associations between CKX gene family members (GFMs) and yield parameters have not yet been assessed. In this study, 17 GmCKX GFMs were identified, and natural variations among GmCKX genes were probed among soybean cultivars with varying yield characteristics. The key CKX genes responsible for regulating CK content during seed filling stages of reproductive development were highlighted using comparative phylogenetics, gene expression analysis and CK metabolite profiling. Five of the seventeen identified GmCKX GFMs, showed natural variations in the form of single nucleotide polymorphisms (SNPs). The gene GmCKX7-1, with high expression during critical seed filling stages, was found to have a non-synonymous mutation (H105Q), on one of the active site residues, Histidine 105, previously reported to be essential for co-factor binding to maintain structural integrity of the enzyme. Soybean lines with this mutation had higher CK content and desired yield characteristics. The potential for marker-assisted selection based on the identified natural variation within GmCKX7-1, is discussed in the context of hormonal control that can result in higher soybean yield.
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Affiliation(s)
| | - Shrikaar Kambhampati
- Department of BiologyTrent UniversityPeterboroughONCanada
- Donald Danforth Plant Science CenterSt. LouisMOUSA
| | - Anna Kisiala
- Department of BiologyTrent UniversityPeterboroughONCanada
| | - Mark Seegobin
- Department of BiologyTrent UniversityPeterboroughONCanada
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Alteration of Electron Acceptor Preferences in the Oxidative Half-Reaction of Flavin-Dependent Oxidases and Dehydrogenases. Int J Mol Sci 2020; 21:ijms21113797. [PMID: 32471202 PMCID: PMC7312611 DOI: 10.3390/ijms21113797] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 05/22/2020] [Accepted: 05/24/2020] [Indexed: 11/30/2022] Open
Abstract
In this review, recent progress in the engineering of the oxidative half-reaction of flavin-dependent oxidases and dehydrogenases is discussed, considering their current and future applications in bioelectrochemical studies, such as for the development of biosensors and biofuel cells. There have been two approaches in the studies of oxidative half-reaction: engineering of the oxidative half-reaction with oxygen, and engineering of the preference for artificial electron acceptors. The challenges for engineering oxidative half-reactions with oxygen are further categorized into the following approaches: (1) mutation to the putative residues that compose the cavity where oxygen may be located, (2) investigation of the vicinities where the reaction with oxygen may take place, and (3) investigation of possible oxygen access routes to the isoalloxazine ring. Among these approaches, introducing a mutation at the oxygen access route to the isoalloxazine ring represents the most versatile and effective strategy. Studies to engineer the preference of artificial electron acceptors are categorized into three different approaches: (1) engineering of the charge at the residues around the substrate entrance, (2) engineering of a cavity in the vicinity of flavin, and (3) decreasing the glycosylation degree of enzymes. Among these approaches, altering the charge in the vicinity where the electron acceptor may be accessed will be most relevant.
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9
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Czajkowska BI, Finlay CM, Jones G, Brown TA. Diversity of a cytokinin dehydrogenase gene in wild and cultivated barley. PLoS One 2019; 14:e0225899. [PMID: 31805120 PMCID: PMC6894797 DOI: 10.1371/journal.pone.0225899] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 11/14/2019] [Indexed: 01/09/2023] Open
Abstract
The cytokinin dehydrogenase gene HvCKX2.1 is the regulatory target for the most abundant heterochromatic small RNAs in drought-stressed barley caryopses. We investigated the diversity of HvCKX2.1 in 228 barley landraces and 216 wild accessions and identified 14 haplotypes, five of these with ten or more members, coding for four different protein variants. The third largest haplotype was abundant in wild accessions (51 members), but absent from the landrace collection. Protein structure predictions indicated that the amino acid substitution specific to haplotype 3 could result in a change in the functional properties of the HvCKX2.1 protein. Haplotypes 1–3 have overlapping geographical distributions in the wild population, but the average rainfall amounts at the collection sites for haplotype 3 plants are significantly higher during November to February compared to the equivalent data for plants of haplotypes 1 and 2. We argue that the likelihood that haplotype 3 plants were excluded from landraces by sampling bias that occurred when the first wild barley plants were taken into cultivation is low, and that it is reasonable to suggest that plants with haplotype 3 are absent from the crop because these plants were less suited to the artificial conditions associated with cultivation. Although the cytokinin signalling pathway influences many aspects of plant development, the identified role of HvCKX2.1 in the drought response raises the possibility that the particular aspect of cultivation that mitigated against haplotype 3 relates in some way to water utilization. Our results therefore highlight the possibility that water utilization properties should be looked on as a possible component of the suite of physiological adaptations accompanying the domestication and subsequent evolution of cultivated barley.
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Affiliation(s)
- Beata I. Czajkowska
- Department of Earth and Environmental Sciences, Manchester Institute of Biotechnology, University of Manchester, Manchester, England, United Kingdom
| | - Conor M. Finlay
- Lydia Becker Institute of Immunology and Inflammation, School of Biological Sciences, University of Manchester, Manchester, England, United Kingdom
| | - Glynis Jones
- Department of Archaeology, University of Sheffield, Northgate House, West Street, Sheffield, England, United Kingdom
| | - Terence A. Brown
- Department of Earth and Environmental Sciences, Manchester Institute of Biotechnology, University of Manchester, Manchester, England, United Kingdom
- * E-mail:
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Jaworek P, Tarkowski P, Hluska T, Kouřil Š, Vrobel O, Nisler J, Kopečný D. Characterization of five CHASE-containing histidine kinase receptors from Populus × canadensis cv. Robusta sensing isoprenoid and aromatic cytokinins. PLANTA 2019; 251:1. [PMID: 31776777 DOI: 10.1007/s00425-019-03297-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 10/17/2019] [Indexed: 06/10/2023]
Abstract
Five poplar CHASE-containing histidine kinase receptors bind cytokinins and display kinase activities. Both endogenous isoprenoid and aromatic cytokinins bind to the receptors in live cell assays. Cytokinins are phytohormones that play key roles in various developmental processes in plants. The poplar species Populus × canadensis, cv. Robusta, is the first organism found to contain aromatic cytokinins. Here, we report the functional characterization of five CHASE-containing histidine kinases from P. × canadensis: PcHK2, PcHK3a, PcHK3b, PcHK4a and PcHK4b. A qPCR analysis revealed high transcript levels of all PcHKs other than PcHK4b across multiple poplar organs. The ligand specificity was determined using a live cell Escherichia coli assay and we provide evidence based on UHPLC-MS/MS data that ribosides can be true ligands. PcHK2 exhibited higher sensitivity to iP-type cytokinins than the other receptors, while PcHK3a and PcHK3b bound these cytokinins much more weakly, because they possess two isoleucine residues that clash with the cytokinin base and destabilize its binding. All receptors display kinase activity but their activation ratios in the presence/absence of cytokinin differ significantly. PcHK4a displays over 400-fold higher kinase activity in the presence of cytokinin, suggesting involvement in strong responses to changes in cytokinin levels. trans-Zeatin was both the most abundant cytokinin in poplar and that with the highest variation in abundance, which is consistent with its strong binding to all five HKs and activation of cytokinin signaling via A-type response regulators. The aromatic cytokinins' biological significance remains unclear, their levels vary diurnally, seasonally, and annually. PcHK3 and PcHK4 display the strongest binding at pH 7.5 and 5.5, respectively, in line with their putative membrane localization in the endoplasmic reticulum and plasma membrane.
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Affiliation(s)
- Pavel Jaworek
- Department of Phytochemistry, Faculty of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University Olomouc, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
- Department of Protein Biochemistry and Proteomics, Faculty of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University Olomouc, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
| | - Petr Tarkowski
- Department of Phytochemistry, Faculty of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University Olomouc, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
- Department of Genetic Resources for Vegetables, Medicinal and Special Plants, Centre of the Region Haná for Biotechnological and Agricultural Research, Crop Research Institute, Šlechtitelů 29, 783 71, Olomouc, Czech Republic
| | - Tomáš Hluska
- Department of Genetic Resources for Vegetables, Medicinal and Special Plants, Centre of the Region Haná for Biotechnological and Agricultural Research, Crop Research Institute, Šlechtitelů 29, 783 71, Olomouc, Czech Republic
| | - Štěpán Kouřil
- Department of Phytochemistry, Faculty of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University Olomouc, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
| | - Ondřej Vrobel
- Department of Phytochemistry, Faculty of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University Olomouc, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
- Department of Genetic Resources for Vegetables, Medicinal and Special Plants, Centre of the Region Haná for Biotechnological and Agricultural Research, Crop Research Institute, Šlechtitelů 29, 783 71, Olomouc, Czech Republic
| | - Jaroslav Nisler
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany, AS CR & Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
| | - David Kopečný
- Department of Protein Biochemistry and Proteomics, Faculty of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University Olomouc, Šlechtitelů 27, 783 71, Olomouc, Czech Republic.
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11
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Wan L, Koeck M, Williams SJ, Ashton AR, Lawrence GJ, Sakakibara H, Kojima M, Böttcher C, Ericsson DJ, Hardham AR, Jones DA, Ellis JG, Kobe B, Dodds PN. Structural and functional insights into the modulation of the activity of a flax cytokinin oxidase by flax rust effector AvrL567-A. MOLECULAR PLANT PATHOLOGY 2019; 20:211-222. [PMID: 30242946 PMCID: PMC6637871 DOI: 10.1111/mpp.12749] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
During infection, plant pathogens secrete effector proteins to facilitate colonization. In comparison with our knowledge of bacterial effectors, the current understanding of how fungal effectors function is limited. In this study, we show that the effector AvrL567-A from the flax rust fungus Melampsora lini interacts with a flax cytosolic cytokinin oxidase, LuCKX1.1, using both yeast two-hybrid and in planta bimolecular fluorescence assays. Purified LuCKX1.1 protein shows catalytic activity against both N6-(Δ2-isopentenyl)-adenine (2iP) and trans-zeatin (tZ) substrates. Incubation of LuCKX1.1 with AvrL567-A results in increased catalytic activity against both substrates. The crystal structure of LuCKX1.1 and docking studies with AvrL567-A indicate that the AvrL567 binding site involves a flexible surface-exposed region that surrounds the cytokinin substrate access site, which may explain its effect in modulating LuCKX1.1 activity. Expression of AvrL567-A in transgenic flax plants gave rise to an epinastic leaf phenotype consistent with hormonal effects, although no difference in overall cytokinin levels was observed. We propose that, during infection, plant pathogens may differentially modify the levels of extracellular and intracellular cytokinins.
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Affiliation(s)
- Li Wan
- School of Chemistry and Molecular Biosciences, Australian Infectious Diseases Research Centre and Institute for Molecular BioscienceUniversity of QueenslandBrisbaneQLD4072Australia
- Department of BiologyUniversity of North CarolinaChapel HillNorth Carolina27599‐3280USA
| | - Markus Koeck
- Commonwealth Scientific and Industrial Research Organisation Agriculture and FoodCanberraACT2601Australia
| | - Simon J. Williams
- School of Chemistry and Molecular Biosciences, Australian Infectious Diseases Research Centre and Institute for Molecular BioscienceUniversity of QueenslandBrisbaneQLD4072Australia
- Division of Plant Sciences, Research School of BiologyAustralian National UniversityCanberraACT2601Australia
| | - Anthony R. Ashton
- Commonwealth Scientific and Industrial Research Organisation Agriculture and FoodCanberraACT2601Australia
| | - Gregory J. Lawrence
- Commonwealth Scientific and Industrial Research Organisation Agriculture and FoodCanberraACT2601Australia
| | - Hitoshi Sakakibara
- RIKEN Center for Sustainable Resource ScienceYokohamaKanagawa230‐0045Japan
| | - Mikiko Kojima
- RIKEN Center for Sustainable Resource ScienceYokohamaKanagawa230‐0045Japan
| | - Christine Böttcher
- Commonwealth Scientific and Industrial Research Organisation Agriculture and FoodAdelaideSA5064Australia
| | - Daniel J. Ericsson
- Australian SynchrotronMacromolecular CrystallographyClaytonVictoria3168Australia
| | - Adrienne R. Hardham
- Division of Plant Sciences, Research School of BiologyAustralian National UniversityCanberraACT2601Australia
| | - David A. Jones
- Division of Plant Sciences, Research School of BiologyAustralian National UniversityCanberraACT2601Australia
| | - Jeffrey G. Ellis
- Commonwealth Scientific and Industrial Research Organisation Agriculture and FoodCanberraACT2601Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Australian Infectious Diseases Research Centre and Institute for Molecular BioscienceUniversity of QueenslandBrisbaneQLD4072Australia
| | - Peter N. Dodds
- Commonwealth Scientific and Industrial Research Organisation Agriculture and FoodCanberraACT2601Australia
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Kumbhar NM, Gopal JS. Structural significance of hypermodified nucleoside 5-carboxymethylaminomethyluridine (cmnm 5U) from 'wobble' (34th) position of mitochondrial tRNAs: Molecular modeling and Markov state model studies. J Mol Graph Model 2018; 86:66-83. [PMID: 30336453 DOI: 10.1016/j.jmgm.2018.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 10/02/2018] [Accepted: 10/04/2018] [Indexed: 11/28/2022]
Abstract
A quantum chemical semi-empirical RM1 approach was used to deduce the structural role of hypermodified nucleoside 5-carboxymethylaminomethyluridine 5'-monophosphate (pcmnm5U) from 'wobble' (34th) position of mitochondrial tRNAs. The energetically preferred pcmnm5U(34) adopted a 'skew' conformation for C5-substituted side chain (-CH2-NH2+-CH2-COO-) moiety that orient towards the 5'-ribose-phosphate backbone, which support 'anti' orientation of glycosyl (χ34) torsion angle. Preferred conformation of pcmnm5U(34) was stabilized by O(4) … HC(10), O1P⋯HN(11), O(15) … HN(11), O(15) … HC(10), O4' … HC(6) and O(2) … HC2' hydrogen bonding interactions. The high flexibility of side chain moiety displayed different structural properties for pcmnm5U(34). Three different conformations of pcmnm5U(34) were observed in molecular dynamics simulations and Markov state model studies. The unmodified uracil revealed 'syn' and 'anti' orientations for glycosyl (χ34) torsion angle that substantiate the role of "-CH2-NH2+-CH2-COO-" moiety in maintaining the 'anti' orientation of pcmnm5U(34). The preferred conformation of pcmnm5U(34) helps to recognize Guanosine more proficiently than Adenosine from the third position of codons. The role of pcmnm5U(34) in tRNA biogenesis paves the way to understand its structural significance in usual mitochondrial metabolism and respiration.
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Affiliation(s)
- Navanath M Kumbhar
- Garware Research Centre, Department of Chemistry, Savitribai Phule Pune University (Formerly University of Pune), Pune, 411007, India.
| | - Janhavi S Gopal
- Institute of Bioinformatics and Biotechnology, Savitribai Phule Pune University (Formerly University of Pune), Pune, 411007, India
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13
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Joshi R, Sahoo KK, Tripathi AK, Kumar R, Gupta BK, Pareek A, Singla-Pareek SL. Knockdown of an inflorescence meristem-specific cytokinin oxidase - OsCKX2 in rice reduces yield penalty under salinity stress condition. PLANT, CELL & ENVIRONMENT 2018; 41:936-946. [PMID: 28337744 DOI: 10.1111/pce.12947] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 02/14/2017] [Accepted: 02/19/2017] [Indexed: 05/04/2023]
Abstract
Cytokinins play a significant role in determining grain yield in plants. Cytokinin oxidases catalyse irreversible degradation of cytokinins and hence modulate cellular cytokinin levels. Here, we studied the role of an inflorescence meristem-specific rice cytokinin oxidase - OsCKX2 - in reducing yield penalty under salinity stress conditions. We utilized an RNAi-based approach to study the function of OsCKX2 in maintaining grain yield under salinity stress condition. Ultra-performance liquid chromatography-based estimation revealed a significant increase in cytokinins in the inflorescence meristem of OsCKX2-knockdown plants. To determine if there exists a correlation between OsCKX2 levels and yield under salinity stress condition, we assessed the growth, physiology and grain yield of OsCKX2-knockdown plants vis-à-vis the wild type. OsCKX2-knockdown plants showed better vegetative growth, higher relative water content and photosynthetic efficiency and reduced electrolyte leakage as compared with the wild type under salinity stress. Importantly, we found a negative correlation between OsCKX2 expression and plant productivity as evident by assessment of agronomical parameters such as panicle branching, filled grains per plant and harvest index both under control and salinity stress conditions. These results suggest that OsCKX2, via controlling cytokinin levels, regulates floral primordial activity modulating rice grain yield under normal as well as abiotic stress conditions.
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Affiliation(s)
- Rohit Joshi
- Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India
| | - Khirod Kumar Sahoo
- Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India
| | - Amit Kumar Tripathi
- Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India
| | - Ritesh Kumar
- Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India
| | - Brijesh Kumar Gupta
- Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India
| | - Ashwani Pareek
- Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Sneh Lata Singla-Pareek
- Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India
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14
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Gigli-Bisceglia N, Engelsdorf T, Strnad M, Vaahtera L, Khan GA, Jamoune A, Alipanah L, Novák O, Persson S, Hejatko J, Hamann T. Cell wall integrity modulates Arabidopsis thaliana cell cycle gene expression in a cytokinin- and nitrate reductase-dependent manner. Development 2018; 145:dev.166678. [DOI: 10.1242/dev.166678] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 08/28/2018] [Indexed: 12/15/2022]
Abstract
During plant growth and defense, cell cycle activity needs to be coordinated with cell wall integrity. Little is known about how coordination is achieved. Here we investigated coordination in Arabidopsis thaliana seedlings by studying the impact of cell wall damage (CWD, caused by cellulose biosynthesis inhibition) on cytokinin homeostasis, cell cycle gene expression and shape in root tips. CWD inhibited cell cycle gene expression and increased transition zone cell width in an osmo-sensitive manner. These results were correlated with CWD-induced, osmo-sensitive changes in cytokinin homeostasis. Expression of CYTOKININ OXIDASE/DEHYDROGENASE2 and 3 (CKX2, CKX3), encoding cytokinin-degrading enzymes was induced by CWD and reduced by osmoticum treatment. In nitrate reductase1 nitrate reductase2 (nia1 nia2) seedlings, neither CKX2 and CKX3 transcript levels were increased nor cell cycle gene expression repressed by CWD. Moreover, established CWD-induced responses like jasmonic acid, salicylic acid and lignin production, were also absent, implying a central role of NIA1- and NIA2-mediated processes in regulation of CWD responses. These results suggest that CWD enhances cytokinin degradation rates through a NIA1 and NIA2-mediated process, subsequently attenuating cell cycle gene expression.
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Affiliation(s)
- Nora Gigli-Bisceglia
- Department of Biology, Høgskoleringen 5, Realfagbygget, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Timo Engelsdorf
- Department of Biology, Høgskoleringen 5, Realfagbygget, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Miroslav Strnad
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany of the Czech Academy of Sciences & Faculty of Science of Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
| | - Lauri Vaahtera
- Department of Biology, Høgskoleringen 5, Realfagbygget, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | | | - Amel Jamoune
- Laboratory of Molecular Plant Physiology and Functional Genomics and Proteomics of Plants CEITEC-Central European Institute of Technology Masaryk University Kamenice 5, CZ-625 00 Brno, Czech Republic
| | - Leila Alipanah
- Department of Biology, Høgskoleringen 5, Realfagbygget, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Ondřej Novák
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany of the Czech Academy of Sciences & Faculty of Science of Palacký University, Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
| | - Staffan Persson
- School of Biosciences, University of Melbourne, Parkville VIC 3010, Australia
| | - Jan Hejatko
- Laboratory of Molecular Plant Physiology and Functional Genomics and Proteomics of Plants CEITEC-Central European Institute of Technology Masaryk University Kamenice 5, CZ-625 00 Brno, Czech Republic
| | - Thorsten Hamann
- Department of Biology, Høgskoleringen 5, Realfagbygget, Norwegian University of Science and Technology, 7491 Trondheim, Norway
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15
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Ewing TA, Fraaije MW, Mattevi A, van Berkel WJ. The VAO/PCMH flavoprotein family. Arch Biochem Biophys 2017; 632:104-117. [DOI: 10.1016/j.abb.2017.06.022] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 06/26/2017] [Accepted: 06/29/2017] [Indexed: 01/15/2023]
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16
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Nisler J, Kopečný D, Končitíková R, Zatloukal M, Bazgier V, Berka K, Zalabák D, Briozzo P, Strnad M, Spíchal L. Novel thidiazuron-derived inhibitors of cytokinin oxidase/dehydrogenase. PLANT MOLECULAR BIOLOGY 2016; 92:235-48. [PMID: 27422623 DOI: 10.1007/s11103-016-0509-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 06/29/2016] [Indexed: 05/11/2023]
Abstract
Two new TDZ derivatives (HETDZ and 3FMTDZ) are very potent inhibitors of CKX and are promising candidates for in vivo studies. Cytokinin hormones regulate a wide range of essential processes in plants. Thidiazuron (N-phenyl-N'-1,2,3-thiadiazol-5-yl urea, TDZ), formerly registered as a cotton defoliant, is a well known inhibitor of cytokinin oxidase/dehydrogenase (CKX), an enzyme catalyzing the degradation of cytokinins. TDZ thus increases the lifetime of cytokinins and their effects in plants. We used in silico modeling to design, synthesize and characterize twenty new TDZ derivatives with improved inhibitory properties. Two compounds, namely 1-[1,2,3]thiadiazol-5-yl-3-(3-trifluoromethoxy-phenyl)urea (3FMTDZ) and 1-[2-(2-hydroxyethyl)phenyl]-3-(1,2,3-thiadiazol-5-yl)urea (HETDZ), displayed up to 15-fold lower IC 50 values compared with TDZ for AtCKX2 from Arabidopsis thaliana and ZmCKX1 and ZmCKX4a from Zea mays. Binding modes of 3FMTDZ and HETDZ were analyzed by X-ray crystallography. Crystal structure complexes, solved at 2.0 Å resolution, revealed that HETDZ and 3FMTDZ bound differently in the active site of ZmCKX4a: the thiadiazolyl ring of 3FMTDZ was positioned over the isoalloxazine ring of FAD, whereas that of HETDZ had the opposite orientation, pointing toward the entrance of the active site. The compounds were further tested for cytokinin activity in several cytokinin bioassays. We suggest that the combination of simple synthesis, lowered cytokinin activity, and enhanced inhibitory effects on CKX isoforms, makes 3FMTDZ and HETDZ suitable candidates for in vivo studies.
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Affiliation(s)
- Jaroslav Nisler
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), Institute of Experimental Botany AS CR, Palacký University, Šlechtitelů 27, 783 71, Olomouc, 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, 783 71, Olomouc, Czech Republic.
- Department of Chemistry of Natural Compounds, Faculty of Food and Biochemical Technology, University of Chemistry and Technology in Prague, Technická 5, 166 28, Prague, 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, Šlechtitelů 27, 783 71, Olomouc, Czech Republic.
| | - Radka Končitíková
- Department of Protein Biochemistry and Proteomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
| | - Marek Zatloukal
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), Institute of Experimental Botany AS CR, Palacký University, Šlechtitelů 27, 783 71, Olomouc, 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, 783 71, Olomouc, Czech Republic
| | - Václav Bazgier
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), Institute of Experimental Botany AS CR, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
- Department of Physical Chemistry, Faculty of Science, Palacký University, 17. listopadu 1192/12, 771 46, Olomouc, Czech Republic
| | - Karel Berka
- Department of Physical Chemistry, Faculty of Science, Palacký University, 17. listopadu 1192/12, 771 46, Olomouc, Czech Republic
- Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University, 17. listopadu 1192/12, 771 46, Olomouc, Czech Republic
| | - David Zalabák
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
| | - Pierre Briozzo
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, Université Paris-Saclay, 78026, Versailles, France
| | - Miroslav Strnad
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), Institute of Experimental Botany AS CR, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
| | - Lukáš Spíchal
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research (CRH), Institute of Experimental Botany AS CR, Palacký University, Šlechtitelů 27, 783 71, Olomouc, 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, 783 71, Olomouc, Czech Republic
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