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Yang B, Pan F, Yasmeen F, Shan L, Pan J, Zhang M, Weng X, Wang M, Li M, Wang Q, Cheng K. Integrated multi-omic analysis reveals the cytokinin and sucrose metabolism-mediated regulation of flavone glycoside biosynthesis by MeJA exposure in Ficus pandurata Hance. Food Res Int 2023; 174:113680. [PMID: 37981372 DOI: 10.1016/j.foodres.2023.113680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 10/29/2023] [Accepted: 11/03/2023] [Indexed: 11/21/2023]
Abstract
Ficus pandurata Hance (FPH) holds a rich history as a traditional Chinese botanical remedy, utilized both as a culinary condiment and a medicinal intervention for diverse ailments. This study focuses on enhancing FPH's therapeutic potential by subjecting it to exogenous methyl jasmonate (MeJA) treatment, a strategy aimed at elevating the levels of active constituents to align with clinical and commercial requirements. Employing metabolomics, the impact of MeJA treatment on the lipid and flavonoid profiles of FPH leaves was investigated, revealing a marked increase in flavone glycosides, a subset of flavonoids. Investigation into the regulatory mechanism governing flavone glycoside biosynthesis uncovered elevated expression of structural genes associated with flavonoid production in response to MeJA exposure. Global endogenous hormone analysis pinpointed the selective activation of JA and cytokinin biosynthesis following MeJA treatment. Through a comprehensive integration of transcriptomic and metabolomic data, the cooperative stimulation of glucosyltransferase activity, alongside the JA and cytokinin signaling pathways, orchestrated by MeJA were explored. Furthermore, genes linked to sucrose metabolism exhibited heightened expression, concomitant with a noteworthy surge in antioxidant activity subsequent to MeJA treatment. These findings validate the augmentation of FPH leaf antioxidant capacity through MeJA intervention, while also offering profound insights into the regulatory role of MeJA in flavone glycoside biosynthesis, mediated by the interplay between cytokinin and sucrose metabolism pathways.
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Affiliation(s)
- Bingxian Yang
- Key Laboratory of Horticultural Plant Growth and Development, Ministry of Agriculture, Department of Horticulture, Zhejiang University, Hangzhou 310058, China; College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China; Chemical Biology Center, Lishui Institute of Agriculture and Forestry Sciences, Lishui 323000, China
| | - Fupeng Pan
- Chemical Biology Center, Lishui Institute of Agriculture and Forestry Sciences, Lishui 323000, China; Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, Zhejiang A & F University, Hangzhou 311300, China
| | - Farhat Yasmeen
- Department of Biosciences, University of Wah, Wah Cantt 47040, Pakistan
| | - Luhuizi Shan
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Junjie Pan
- Chemical Biology Center, Lishui Institute of Agriculture and Forestry Sciences, Lishui 323000, China
| | - Meng Zhang
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Xinying Weng
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Mengyu Wang
- Key Laboratory of Horticultural Plant Growth and Development, Ministry of Agriculture, Department of Horticulture, Zhejiang University, Hangzhou 310058, China
| | - Mengxin Li
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Qiaomei Wang
- Key Laboratory of Horticultural Plant Growth and Development, Ministry of Agriculture, Department of Horticulture, Zhejiang University, Hangzhou 310058, China.
| | - Kejun Cheng
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China; Chemical Biology Center, Lishui Institute of Agriculture and Forestry Sciences, Lishui 323000, China; Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, Zhejiang A & F University, Hangzhou 311300, China.
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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, Jameson GB, Guo Y, Song J, Jameson PE. The LONELY GUY gene family: from mosses to wheat, the key to the formation of active cytokinins in plants. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:625-645. [PMID: 35108444 PMCID: PMC8989509 DOI: 10.1111/pbi.13783] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 01/06/2022] [Accepted: 01/13/2022] [Indexed: 05/19/2023]
Abstract
LONELY GUY (LOG) was first identified in a screen of rice mutants with defects in meristem maintenance. In plants, LOG codes for cytokinin riboside 5'-monophosphate phosphoribohydrolase, which converts inactive cytokinin nucleotides directly to the active free bases. Many enzymes with the PGGxGTxxE motif have been misannotated as lysine decarboxylases; conversely not all enzymes containing this motif are cytokinin-specific LOGs. As LOG mutants clearly impact yield in rice, we investigated the LOG gene family in bread wheat. By interrogating the wheat (Triticum aestivum) genome database, we show that wheat has multiple LOGs. The close alignment of TaLOG1, TaLOG2 and TaLOG6 with the X-ray structures of two functional Arabidopsis thaliana LOGs allows us to infer that the wheat LOGs 1-11 are functional LOGs. Using RNA-seq data sets, we assessed TaLOG expression across 70 tissue types, their responses to various stressors, the pattern of cis-regulatory elements (CREs) and intron/exon patterns. TaLOG gene family members are expressed variously across tissue types. When the TaLOG CREs are compared with those of the cytokinin dehydrogenases (CKX) and glucosyltransferases (CGT), there is close alignment of CREs between TaLOGs and TaCKXs reflecting the key role of CKX in maintaining cytokinin homeostasis. However, we suggest that the main homeostatic mechanism controlling cytokinin levels in response to biotic and abiotic challenge resides in the CGTs, rather than LOG or CKX. However, LOG transgenics and identified mutants in rice variously impact yield, providing interesting avenues for investigation in wheat.
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Affiliation(s)
- Lei Chen
- School of Life SciencesYantai UniversityYantaiChina
| | | | - Yichu Guo
- School of Life SciencesYantai UniversityYantaiChina
| | - Jiancheng Song
- School of Life SciencesYantai UniversityYantaiChina
- Yantai Jien Biological Science & Technology LtdYEDAYantaiChina
| | - Paula E. Jameson
- School of Life SciencesYantai UniversityYantaiChina
- School of Biological SciencesUniversity of CanterburyChristchurchNew 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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The Hulks and the Deadpools of the Cytokinin Universe: A Dual Strategy for Cytokinin Production, Translocation, and Signal Transduction. Biomolecules 2021; 11:biom11020209. [PMID: 33546210 PMCID: PMC7913349 DOI: 10.3390/biom11020209] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 01/27/2021] [Accepted: 01/28/2021] [Indexed: 02/06/2023] Open
Abstract
Cytokinins are plant hormones, derivatives of adenine with a side chain at the N6-position. They are involved in many physiological processes. While the metabolism of trans-zeatin and isopentenyladenine, which are considered to be highly active cytokinins, has been extensively studied, there are others with less obvious functions, such as cis-zeatin, dihydrozeatin, and aromatic cytokinins, which have been comparatively neglected. To help explain this duality, we present a novel hypothesis metaphorically comparing various cytokinin forms, enzymes of CK metabolism, and their signalling and transporter functions to the comics superheroes Hulk and Deadpool. Hulk is a powerful but short-lived creation, whilst Deadpool presents a more subtle and enduring force. With this dual framework in mind, this review compares different cytokinin metabolites, and their biosynthesis, translocation, and sensing to illustrate the different mechanisms behind the two CK strategies. This is put together and applied to a plant developmental scale and, beyond plants, to interactions with organisms of other kingdoms, to highlight where future study can benefit the understanding of plant fitness and productivity.
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Identification of Potential Metabolic Markers for the Selection of a High-Yield Clone of Quercus acutissima in Clonal Seed Orchard. FORESTS 2018. [DOI: 10.3390/f9030116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Frébort I, Kowalska M, Hluska T, Frébortová J, Galuszka P. Evolution of cytokinin biosynthesis and degradation. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:2431-52. [PMID: 21321050 DOI: 10.1093/jxb/err004] [Citation(s) in RCA: 219] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Cytokinin hormones are important regulators of development and environmental responses of plants that execute their action via the molecular machinery of signal perception and transduction. The limiting step of the whole process is the availability of the hormone in suitable concentrations in the right place and at the right time to interact with the specific receptor. Hence, the hormone concentrations in individual tissues, cells, and organelles must be properly maintained by biosynthetic and metabolic enzymes. Although there are merely two active cytokinins, isopentenyladenine and its hydroxylated derivative zeatin, a variety of conjugates they may form and the number of enzymes/isozymes with varying substrate specificity involved in their biosynthesis and conversion gives the plant a variety of tools for fine tuning of the hormone level. Recent genome-wide studies revealed the existence of the respective coding genes and gene families in plants and in some bacteria. This review summarizes present knowledge on the enzymes that synthesize cytokinins, form cytokinin conjugates, and carry out irreversible elimination of the hormones, including their phylogenetic analysis and possible variations in different organisms.
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Affiliation(s)
- Ivo Frébort
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 813/21, CZ-78371 Olomouc, Czech Republic.
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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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11
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Zažímalová E, Kamínek M, Březinová A, Motyka V. Control of cytokinin biosynthesis and metabolism. BIOCHEMISTRY AND MOLECULAR BIOLOGY OF PLANT HORMONES 1999. [DOI: 10.1016/s0167-7306(08)60486-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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12
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Sembdner G, Atzorn R, Schneider G. Plant hormone conjugation. PLANT MOLECULAR BIOLOGY 1994; 26:1459-1481. [PMID: 7858200 DOI: 10.1007/bf00016485] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- G Sembdner
- Institut für Pflanzenbiochemie, Halle, Germany
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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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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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The Identity of the Major Metabolite of Benzylaminopurine in Soybean Cultures, and the Inhibition of Its Formation by Aminophylline. ACTA ACUST UNITED AC 1982. [DOI: 10.1016/s0304-4211(82)80005-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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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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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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Scott IM, Horgan R, McGaw BA. Zeatin-9-glucoside, a major endogenous cytokinin of Vinca rosea L. crown gall tissue. PLANTA 1980; 149:472-475. [PMID: 24306475 DOI: 10.1007/bf00385750] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/1980] [Accepted: 04/09/1980] [Indexed: 06/02/2023]
Abstract
Cultured crown gall tissue of Vinca rosea L. was found to contain, in addition to the previously reported cytokinins zeatin, zeatin riboside, and the 0-glucosides of these two compounds, relatively high levels of zeatin-9-D-glucopyranoside. This is the first conclusive identification of an endogenous cytokinin 9-glucoside.
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Affiliation(s)
- I M Scott
- Department of Botany and Microbiology, University College of Wales, SY23 3DA, Aberystwyth, UK
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Weiler EW. Radioimmunoassays for trans-zeatin and related cytokinins. PLANTA 1980; 149:155-62. [PMID: 24306247 DOI: 10.1007/bf00380877] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/1979] [Accepted: 01/20/1980] [Indexed: 05/04/2023]
Abstract
Radioimmunoassays for the quantitation of trans-zeatin and related cytokinins have been developed. Antisera produced against bovine serum albumin conjugates of trans-zeatinriboside have a high affinity (Ka=2.4.10(-11) M) for zeatinriboside and for zeatin, but show a negligible cross reaction to isopentenyladenosine (0.1%) and cis-zeatinriboside (0.4%), only a slight cross reaction to dihydrozeatin (1.7%), and no cross reaction at all to other purines, such as adenosine and related, compounds, was observed. The assays are sensitive and measuring ranges extend from 0.06-30 pmol (0.02-10 ng) of zeatinriboside. This has been achieved by employing as tracers immunoreactive zeatin derivatives with high-specific activity, (tritiated zeatinriboside-dialcohol: 8.37.10(11) Bq mmol(-1) and zeatinribosyl-[(125)I]tyramine: ca. 1.9.10(13) Bq mmol(-1). The detection limit is 40 fmol (15pg) for the assay employing the tritiated tracer, and assay reproducibility is high (variation coefficients of triplicates less than 5%). Several hundred assays can be completed in one day, and, due to the high specificity of this assay, crude extracts may be used for analysis. The course of zeatin levels in developing fruits of Lycopersicon esculentum cv. Moneymaker is given.
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Affiliation(s)
- E W Weiler
- Lehrstuhl für Pflanzenphysiologie, Ruhr-Universität Bochum, Postfach 102148, D-4630, Bochum 10, Germany
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Summons RE, Entsch B, Letham DS, Gollnow BI, Macleod JK. Regulators of cell division in plant tissues : XXVIII. Metabolites of zeatin in sweet-corn kernels: Purifications and identifications using high-performance liquid chromatography and chemical-ionization mass spectrometry. PLANTA 1980; 147:422-434. [PMID: 24311164 DOI: 10.1007/bf00380183] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/1979] [Accepted: 11/19/1979] [Indexed: 06/02/2023]
Abstract
The cytokinins in certain fractions prepared from extracts of immature sweet-corn (Zea mays L.) kernels using polystyrene ion-exchange resins have been further investigated. Cytokinins active in the radish cotyledon bioassay were purified from these fractions and identified as 9-β-D-glucopyranosylzeatin, 9-β-D-glucopyranosyldihydrozeatin, O-β-D-glucopyranosylzeatin. and O-β-D-glucopyranosyl-9-β-D-ribofuranosylzeatin. In addition, compounds which resemble zeatin and its glycosides in chromatographic behaviour and in ultraviolet absorption characteristics were purified from extracts of the same material by high-performance liquid chromatography. In addition to zeatin and zeatin riboside, the following compounds were identified unambiguously: O-β-D-glucopyranosyl-9-β-D-ribofuranosyldihydrozeatin, O-β-D-glucopyranosyldihydrozeatin, and hihydrozeatin riboside. A further compound was tentatively identified as O-β-D-glucopyranosylzeatin, and at least two unidentified compounds appeared to be new derivatives of zeatin. In identifying the above compounds, chemical-ionization mass spectrometry proved to be an invaluable complementary technique, yielding spectra showing intense protonated-molecular-ion peaks and also prominent structure-related fragmentation that was either not evident or very minor in the electron-impact spectra. An assessment of the relative importance of the various possible mechanisms for cytokinin modification and inactivation in mature sweet-corn kernels was made by supplying [(3)H]zeatin and [(3)H]zeatin riboside to such kernels after excision. The principal metabolites of zeatin were adenine nucleotides, adenosine and adenine, while little of the metabolite radioactivity was attributable to known O-glucosides. Adenine nucleotides and adenine were the principal metabolites of zeatin riboside, while lesser metabolites were identified as adenosine, dihydrozeatin, and the O-glucosides of dihydrozeatin and dihydrozeatin riboside. Side-chain cleavage, rather than side-chain modification, appears to be the dominant form of cytokinin metabolism in mature sweet-corn kernels.
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Entsch B, Parker CW, Letham DS, Summons RE. Preparation and characterization, using high-performance liquid chromatography, of an enzyme forming glucosides of cytokinins. BIOCHIMICA ET BIOPHYSICA ACTA 1979; 570:124-39. [PMID: 486500 DOI: 10.1016/0005-2744(79)90207-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cytokinins can occur naturally as glycosides with beta-D-glucose as the sugar substituent. From radish (Raphanus sativus) cotyledons, an enzyme has been partly purified which synthesizes the 7-glucopyranoside of zeatin [6-(4-hydroxy-3-methylbut-trans-2-enylamino)purine], a compound known to occur in this species. High-performance reverse-phase liquid chromatography was uniquely useful as the analytical procedure for quantitative study of the minute amounts of enzyme available. The enzyme uses UDPglucose as the source of the sugar residue. A large number of derivatives of purine are glucosylated, but adenine derivatives with an alkyl side chain at least three carbon atoms in length at position N6 are preferentially glucosylated. This corresponds to the structural features required for high cytokinin activity. The 7-glucoside of zeatin is known to be very weakly active in cytokinin bioassays. Hence, this enzyme, and others catalyzing the same reaction, have a role in the regulation of cytokinin activity.
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Summons RE, Duke CC, Eichholzer JV, Entsch B, Letham DS, MacLeod JK, Parker CW. Mass spectrometric analysis of cytokinins in plant tissues. II—Quantitation of cytokinins inZea mays kernels using deuterium labelled standards. ACTA ACUST UNITED AC 1979. [DOI: 10.1002/bms.1200060908] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Letham DS, Summons RE, Parker CW, Macleod JK. Regulators of cell division in plant tissues : XXVII. Identification of an amino-acid conjugate of 6-benzylaminopurine formed in Phaseolus vulgaris seedlings. PLANTA 1979; 146:71-74. [PMID: 24317948 DOI: 10.1007/bf00381257] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/1978] [Revised: 12/12/1978] [Accepted: 02/12/1979] [Indexed: 06/02/2023]
Abstract
6-[(3)H]Benzylaminopurine was supplied through the transpiration stream to de-rooted Phaseolus vulgaris L. seedlings. The principal metabolite formed was identified as β-(6-benzylaminopurin-9-yl)alanine by comparison with the synthetic compound.
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Affiliation(s)
- D S Letham
- Research School of Biological Sciences and Research School of Chemistry, Australian National University, Box 475, P.O., 2601, Canberra, A.C.T., Australia
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