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Jameson PE. Cytokinin Translocation to, and Biosynthesis and Metabolism within, Cereal and Legume Seeds: Looking Back to Inform the Future. Metabolites 2023; 13:1076. [PMID: 37887400 PMCID: PMC10609209 DOI: 10.3390/metabo13101076] [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: 09/13/2023] [Revised: 10/08/2023] [Accepted: 10/10/2023] [Indexed: 10/28/2023] Open
Abstract
Early in the history of cytokinins, it was clear that Zea mays seeds contained not just trans-zeatin, but its nucleosides and nucleotides. Subsequently, both pods and seeds of legumes and cereal grains have been shown to contain a complex of cytokinin forms. Relative to the very high quantities of cytokinin detected in developing seeds, only a limited amount appears to have been translocated from the parent plant. Translocation experiments, and the detection of high levels of endogenous cytokinin in the maternal seed coat tissues of legumes, indicates that cytokinin does not readily cross the maternal/filial boundary, indicating that the filial tissues are autonomous for cytokinin biosynthesis. Within the seed, trans-zeatin plays a key role in sink establishment and it may also contribute to sink strength. The roles, if any, of the other biologically active forms of cytokinin (cis-zeatin, dihydrozeatin and isopentenyladenine) remain to be elucidated. The recent identification of genes coding for the enzyme that leads to the biosynthesis of trans-zeatin in rice (OsCYP735A3 and 4), and the identification of a gene coding for an enzyme (CPN1) that converts trans-zeatin riboside to trans-zeatin in the apoplast, further cements the key role played by trans-zeatin in plants.
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Affiliation(s)
- Paula E Jameson
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
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Jameson PE. Zeatin: The 60th anniversary of its identification. PLANT PHYSIOLOGY 2023; 192:34-55. [PMID: 36789623 PMCID: PMC10152681 DOI: 10.1093/plphys/kiad094] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 05/03/2023]
Abstract
While various labs had shown cell division-inducing activity in a variety of plant extracts for over a decade, the identification of zeatin (Z) in 1964, the first known naturally occurring cytokinin, belongs to Letham and co-workers. Using extracts from maize (Zea mays), they were the first to obtain crystals of pure Z and in sufficient quantity for structural determination by MS, NMR, chromatography, and mixed melting-point analysis. This group also crystallized Z-9-riboside (ZR) from coconut (Cocos nucifera) milk. However, their chemical contributions go well beyond the identification of Z and ZR and include two unambiguous syntheses of trans-Z (to establish stereochemistry), the synthesis of 3H-cytokinins that facilitated metabolic studies, and the synthesis of deuterated internal standards for accurate mass spectral quantification. Letham and associates also unequivocally identified Z nucleotide, the 7-and 9-glucoside conjugates of Z, and the O-glucosides of Z, ZR, dihydro Z (DHZ) and DHZR as endogenous compounds and as metabolites of exogenous Z. Their contributions to the role of cytokinins in plant physiology and development were also substantial, especially the role of cytokinins moving in the xylem. These biological advances are described and briefly related to the genetic/molecular biological contributions of others that established that plants have an absolute requirement for cytokinin.
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Affiliation(s)
- Paula Elizabeth Jameson
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
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Chen L, Zhao J, Song J, Jameson PE. Cytokinin glucosyl transferases, key regulators of cytokinin homeostasis, have potential value for wheat improvement. PLANT BIOTECHNOLOGY JOURNAL 2021; 19:878-896. [PMID: 33811433 PMCID: PMC8131048 DOI: 10.1111/pbi.13595] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/28/2021] [Indexed: 05/05/2023]
Abstract
The cytokinins, which are N6 -substituted adenine derivatives, control key aspects of crop productivity. Cytokinin levels are controlled via biosynthesis by isopentenyl transferase (IPT), destruction by cytokinin oxidase/dehydrogenase (CKX), and inactivation via glucosylation by cytokinin glucosyl transferases (CGTs). While both yield components and tolerance to drought and related abiotic stressors have been positively addressed via manipulation of IPT and/or CKX expression, much less attention has been paid to the CGTs. As naming of the CGTs has been unclear, we suggest COGT, CNGT, CONGT and CNOGT to describe the O-, N- and dual function CGTs. As specific CGT mutants of both rice and arabidopsis showed impacts on yield components, we interrogated the wheat genome database, IWGSC RefSeq v1.0 & v2.0, to investigate wheat CGTs. Besides providing unambiguous names for the 53 wheat CGTs, we show their expression patterns in 70 developmental tissues and their response characteristics to various stress conditions by reviewing more than 1000 RNA-seq data sets. These revealed various patterns of responses and showed expression generally being more limited in reproductive tissues than in vegetative tissues. Multiple cis-regulatory elements are present in the 3 kb upstream of the start codons of the 53 CGTs. Elements associated with abscisic acid, light and methyl jasmonate are particularly over-represented, indicative of the responsiveness of CGTs to the environment. These data sets indicate that CGTs have potential value for wheat improvement and that these could be targeted in TILLING or gene editing wheat breeding programmes.
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Affiliation(s)
- Lei Chen
- School of Life SciencesYantai UniversityYantaiChina
| | - Jing Zhao
- School of Life SciencesYantai UniversityYantaiChina
| | | | - Paula E. Jameson
- School of Life SciencesYantai UniversityYantaiChina
- School of Biological SciencesUniversity of CanterburyChristchurchNew Zealand
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Werner T, Hanus J, Holub J, Schmülling T, Van Onckelen H, Strnad M. New cytokinin metabolites in IPT transgenic Arabidopsis thaliana plants. PHYSIOLOGIA PLANTARUM 2003; 118:127-137. [PMID: 12702021 DOI: 10.1034/j.1399-3054.2003.00094.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Two novel cytokinin metabolites were identified in transgenic Arabidopsis thaliana (L.) Heynh. plants containing the bacterial IPT gene under the transcriptional control of a heat-regulated promoter. After cyclic heat-shock treatment, the endogenous cytokinin concentrations were elevated up to 100-fold compared to the wild-type plants. More then 20 different cytokinin metabolites were found, with zeatin-type cytokinins being the most abundant. The metabolic inactivation of these compounds occurred predominantly through N-glucosylation. No significant accumulation of isopentenyladenine-type cytokinins, and only a small increase in dihydrozeatin metabolites, was observed. Subsequent studies of the abundant, unidentified conjugates revealed the presence of zeatin and dihydrozeatin diglucoside conjugates. Structural analysis, utilizing electrospray-liquid tandem mass spectrometry, identified these as a zeatin-O-glucoside-9-glucoside and dihydrozeatin-O-glucoside-9-glucoside, respectively. A third unknown metabolite, was tentatively identified as a phosphorylated form of zeatin-9-glucoside. The biological activity of these compounds in three cytokinin bioassays was low. A comparison of the cytokinin pattern in transgenic and wild-type plants indicates that these specific metabolites accumulate as a consequence of enhanced cytokinin biosynthesis, and are probably involved in the homeostatic mechanisms that control endogenous cytokinin levels.
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Affiliation(s)
- Tomás Werner
- Laboratory of Growth Regulators, Palacký University & Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 783 71 Olomouc, Czech Republic Isotope Laboratory, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 142 20 Praha, Czech Republic Institute of Biology, Free University of Berlin, D-14195 Berlin, Germany Laboratory for Plant Biochemistry and Physiology, Department of Biology, University of Antwerp, B-2610 Antwerp, Belgium
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Martin RC, Mok MC, Habben JE, Mok DW. A maize cytokinin gene encoding an O-glucosyltransferase specific to cis-zeatin. Proc Natl Acad Sci U S A 2001; 98:5922-6. [PMID: 11331778 PMCID: PMC33314 DOI: 10.1073/pnas.101128798] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Zeatin is a naturally occurring cytokinin. Biosynthesis and metabolism studies of zeatin have been directed mostly at the trans isomer, although cis-zeatin and its riboside occur as major components in some plant species. It is not known whether parallel regulatory pathways exist for the two isomers. Based on the sequence of the gene ZOG1 encoding a trans-zeatin O-glucosyltransferase from Phaseolus (EC ), a cis-zeatin-specific O-glucosyltransferase was isolated from maize. This gene, cisZOG1, contains an ORF of 1,401 nucleotides encoding a protein of 51.1 kDa with 41% identity to the Phaseolus ZOG1 protein. Unexpectedly, the maize enzyme recognizes as substrates cis-zeatin and UDP-glucose but not cis-ribosylzeatin, trans-zeatin, or trans-ribosylzeatin. This finding indicates the existence of cis-specific regulatory elements in plants and suggests that cis-zeatin and derivatives may be more important in cytokinin homeostasis than currently recognized.
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Affiliation(s)
- R C Martin
- Department of Horticulture and Center for Gene Research and Biotechnology, Oregon State University, Corvallis, OR 97331-7304, USA
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Blanco MH, Quintana MDC, Hernández L. Determination of Dihydrozeatin and Dihydrozeatin Riboside by Cathodic Stripping Voltammetry. ELECTROANAL 2000. [DOI: 10.1002/(sici)1521-4109(200002)12:2<147::aid-elan147>3.0.co;2-f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Hernández P, Paton F, Ballesteros Y, Hernández L. Voltammetry study of zeatin in a carbon fiber ultramicroelectrode. Determination by adsorptive stripping. ELECTROANAL 1997. [DOI: 10.1002/elan.1140090309] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Hormonal Regulation of Seed Development. ADVANCES IN CELLULAR AND MOLECULAR BIOLOGY OF PLANTS 1997. [DOI: 10.1007/978-94-015-8909-3_4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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Identification of O-α-d-galactopyranosylsaccharinic acids as their trimethylsilyl derivatives by mass spectrometry. Carbohydr Res 1989. [DOI: 10.1016/0008-6215(89)85004-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Hutton M, Van Staden J. Transport and Metabolism of Labelled Zeatin Applied to the Stems of Phaseolus vulgaris at Different Stages of Development. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/s0044-328x(84)80088-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Palni LM, Palmer MV, Letham DS. The stability and biological activity of cytokinin metabolites in soybean callus tissue. PLANTA 1984; 160:242-9. [PMID: 24258507 DOI: 10.1007/bf00402861] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/1983] [Accepted: 11/02/1983] [Indexed: 05/04/2023]
Abstract
The activity, uptake and metabolism of cytokinin metabolites was determined in soybean (Glycine max (L.) Merr.) callus tissue. The following activity sequence was established: zeatin riboside (ZR)>zeatin (Z)>O-glucosides of Z, ZR and their dihydro derivatives>lupinic acid (an alanine conjugate of Z)>7- and 9-glucosides of Z which were almost inactive. The 7- and 9-glucosides and lupinic acid were taken up very slowly by the callus tissue and showed great metabolic stability, but some degradation to 7-glucosyladenine, 9-glucosyladenine and the 9-alanine conjugate of adenine occurred. Compared with its aglycone, O-glucosyl-ZR exhibited slow uptake and greatly enhanced stability but gas chromatographic-mass spectrometric analysis showed that appreciable amounts were hydrolyzed to ZR in the tissue. Both ZR and O-glucosyl-ZR were metabolised extensively, with adenine, adenosine, and adenine nucleotide(s) as the major metabolites. A diversity of minor metabolites of ZR were identified, including O-glucosides, lupinic acid and dihydrolupinic acid. The metabolism of ZR was suppressed by 3-isobutyl-1-methylxanthine. When compared with the soybean callus line normally used for cytokinin bioassays (cv. Acme, cotyledonary callus), related callus lines exhibited greatly differing growth responses to cytokinin: however, these were not reflected in marked differences in metabolism.
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Affiliation(s)
- L M Palni
- Research School of Biological Sciences, Australian National University, P.O. Box 475, 2601, Canberra City, ACT, Australia
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Tsui C, Shao L, Wang C, Tao GQ, Letham D, Parker C, Summons R, Hocart C. Identification of a cytokinin in water chestnuts (corms of Eleocharis tuberosa). ACTA ACUST UNITED AC 1983. [DOI: 10.1016/0304-4211(83)90119-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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McGaw BA, Horgan R. Cytokinin oxidase fromZea mays kernels andVinca rosea crown-gall tissue. PLANTA 1983; 159:30-7. [PMID: 24258083 DOI: 10.1007/bf00998811] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/1983] [Accepted: 05/05/1983] [Indexed: 05/11/2023]
Abstract
Cytokinin oxidase has been partially purified from matureZea mays kernels and fromVinca rosea corwn-gall tissue. The molecular weights of the two enzymes, determined by gel filtration, are very different: 94,400 (±10%) forZ. mays and 25,100 (±10%) forV. rosea. Specificity studies have been performed using a large number of synthetic and naturally occurring cytokinins. Only a small number of these compounds serve as substrates and both enzymes exhibit similar substrate specificity. In agreement with other workers, a Δ(2) double bond in the N(6) side chain is essential for activity. The presence of glucosyl or ribosyl groups in the 7-or 9-position or an alanyl group in the 9-position of the purine moiety have little effect on their susceptibility to cytokinin oxidase, but O-glucosyl derivatives are resistant to oxidation. The relevance of these enzyme systems to studies on cytokinin metabolism and to the endogenous cytokinins is discussed.
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Affiliation(s)
- B A McGaw
- Department of Botany and Microbiology, University College of Wales, SY23 3DA, Aberystwyth, Dyfed, UK
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Sjut V, Palmer M. Reversed-phase high-performance liquid chromatography of plant hormones: some useful differences in stationary phase selectivity. J Chromatogr A 1983. [DOI: 10.1016/s0021-9673(01)96377-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Palmer M, Scott I, Horgan R. Cytokinin metabolism in Phaseolus vulgaris L. II. Comparative metabolism of exogenous cytokinins by detached leaves. ACTA ACUST UNITED AC 1981. [DOI: 10.1016/0304-4211(81)90141-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Laloue M, Pethe-Terrine C, Guern J. Uptake and Metabolism of Cytokinins in Tobacco Cells: Studies in Relation to the Expression of Their Biological Activities. ACTA ACUST UNITED AC 1981. [DOI: 10.1007/978-3-642-68035-9_8] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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Cytokinin Translocation and Metabolism in Species of the Leguminoseae: Studies in Relation to Shoot and Nodule Development. PROCEEDINGS IN LIFE SCIENCES 1981. [DOI: 10.1007/978-3-642-68035-9_7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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