Cytokinins as regulators of gene expression

Schmülling, Thomas; Schäfer, Silke; Romanov, G. A.

doi:10.1034/j.1399-3054.1997.1000312.x

Cited by 41 publications

(40 citation statements)

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“…This was due exclusively to an increase in the production of 1,3,6,7 xanthones. Changes on the expression and activity of several enzymes due to the action of auxins and cytokinins, including enzymes from the phenylpropanoid pathway, have been reported by other authors ( [24,25], and refs. therein).…”

Section: Effects Of Phytohormones On Xanthone Accumulation In H Andrmentioning

confidence: 83%

“…This was due to an increase in the production of other unidentified 1,3,5,6 xanthones by suspended cells. These results indicate that in spite of the fact that culture media and particularly phytohormones play an important role in regulation of secondary metabolism [11][12][13]24,25], a balance of several other factors also determines secondary metabolites accumulation. The cell suspensions of H. androsaemum are characterized mainly by isolated cells and small aggregates of two to ten cells, occasionally reaching 1 mm in diameter, in a dedifferenciated state.…”

Section: Xanthone Accumulation In Suspended Cells 6ersus Callimentioning

confidence: 88%

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Xanthone biosynthesis and accumulation in calli and suspended cells of Hypericum androsaemum

et al. 2000

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Calli and suspended cells of Hypericum androsaemum accumulated high levels of 1,3,5,6 and 1,3,6,7 oxygenated xanthones. The major compounds include simple oxygenated xanthones or derivatives with prenyl, pyran or methoxyl groups, four of them being new natural compounds. A hypothetical biosynthetic scheme is proposed based on the isolated compounds and statistical analysis. Xanthone accumulation was influenced greatly by medium factors, namely hormone supplementation. Calli grown with 4.5 mM a-naphtaleneacetic acid (NAA) +2.3 mM kinetin (KIN) had the highest specific xanthone production (1.3% biomass dry weight (DW)), whereas suspended cells grown in similar medium accumulated a lower amount (0.87% DW). Calli displayed a negative linear relationship between total xanthone accumulation and NAA concentration, in the range of 4.5 -22.5 mM. However, in this range the xanthone 1,3,6,7/1,3,5,6 ratio and the biomass production showed a positive linear relationship with NAA concentration. Substitution of 4.5 mM of NAA by the same molar amount of 2,4-dichlorophenoxyacetic acid (2,4-D), in the presence of 2.3 mM of KIN, caused a decrease in xanthone accumulation in calli. The use of N 6 -benzyladenine (BA) instead of KIN reduced xanthone production, independently of the auxin used. This effect was attenuated when both hormones were present.

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Section: Effects Of Phytohormones On Xanthone Accumulation In H Andrmentioning

confidence: 83%

Section: Xanthone Accumulation In Suspended Cells 6ersus Callimentioning

confidence: 88%

Xanthone biosynthesis and accumulation in calli and suspended cells of Hypericum androsaemum

et al. 2000

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“…The expression of various genes is modulated by this hormone, and numerous cytokinin-regulated genes have been described (Schmü lling et al, 1997;Rashotte et al, 2003). Phosphotransfer between His and Asp residues of signaling proteins, generally referred to as a twocomponent regulatory system or a His-Asp phosphorelay, is involved in cytokinin signal transduction (Inoue et al, 2001;Kieber, 2001;Schmü lling, 2001;Suzuki et al, 2001;Kakimoto, 2003).…”

mentioning

confidence: 99%

Molecular Characterization of Cytokinin-Responsive Histidine Kinases in Maize. Differential Ligand Preferences and Response to cis-Zeatin

et al. 2004

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Genes for cytokinin-responsive His-protein kinases (ZmHK1, ZmHK2, and ZmHK3a) were isolated from maize (Zea mays). Heterologous expression of each of the ZmHKs in Escherichia coli having the DrcsC and cps::lacZ genetic background conferred cytokinin-inducibility of lacZ expression on the bacteria. In the recombinant E. coli system, ZmHK1 and ZmHK3a were more sensitive to free-base cytokinins than to the corresponding nucleosides; isopentenyladenine was most effective for ZmHK1, while ZmHK2 tended to be most sensitive to trans-zeatin and the riboside. In contrast to a known cytokinin receptor of Arabidopsis (AHK4/CRE1/WOL), all ZmHKs responded to cis-zeatin (cZ), which generally is believed to be inactive or only weakly active. In cultured maize cells, expression of ZmRR1, a cytokinin-inducible response regulator, was induced by cZ as well as by trans-zeatin. These results strongly suggest that maize cytokinin receptors differ in ligand preference, and that cZ is an active cytokinin at least in maize.

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“…In contrast to brassinosteroids and gibberellins, which repress photomorphogenesis and negatively regulate chloroplast development (Li and Chory, 1999;Alabadí and Blázquez, 2009), cytokinins promote the etioplast-tochloroplast transition and the formation of the electron transport chain (Cherniad'ev, 2000) and control the expression of nuclear chloroplast genes (Schmü lling et al, 1997). In response to ethylene, nuclear photosynthesis genes are generally down-regulated.…”

Section: Hormonesmentioning

confidence: 99%

Intracompartmental and Intercompartmental Transcriptional Networks Coordinate the Expression of Genes for Organellar Functions

et al. 2011

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(X.W., G.H., K.F.X.M.)Genes for mitochondrial and chloroplast proteins are distributed between the nuclear and organellar genomes. Organelle biogenesis and metabolism, therefore, require appropriate coordination of gene expression in the different compartments to ensure efficient synthesis of essential multiprotein complexes of mixed genetic origin. Whereas organelle-to-nucleus signaling influences nuclear gene expression at the transcriptional level, organellar gene expression (OGE) is thought to be primarily regulated posttranscriptionally. Here, we show that intracompartmental and intercompartmental transcriptional networks coordinate the expression of genes for organellar functions. Nearly 1,300 ATH1 microarray-based transcriptional profiles of nuclear and organellar genes for mitochondrial and chloroplast proteins in the model plant Arabidopsis (Arabidopsis thaliana) were analyzed. The activity of genes involved in organellar energy production (OEP) or OGE in each of the organelles and in the nucleus is highly coordinated. Intracompartmental networks that link the OEP and OGE gene sets serve to synchronize the expression of nucleus-and organelle-encoded proteins. At a higher regulatory level, coexpression of organellar and nuclear OEP/OGE genes typically modulates chloroplast functions but affects mitochondria only when chloroplast functions are perturbed. Under conditions that induce energy shortage, the intercompartmental coregulation of photosynthesis genes can even override intracompartmental networks. We conclude that dynamic intracompartmental and intercompartmental transcriptional networks for OEP and OGE genes adjust the activity of organelles in response to the cellular energy state and environmental stresses, and we identify candidate cis-elements involved in the transcriptional coregulation of nuclear genes. Regarding the transcriptional regulation of chloroplast genes, novel tentative target genes of s factors are identified.

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Cytokinins as regulators of gene expression

Cited by 41 publications

References 0 publications

Xanthone biosynthesis and accumulation in calli and suspended cells of Hypericum androsaemum

Xanthone biosynthesis and accumulation in calli and suspended cells of Hypericum androsaemum

Molecular Characterization of Cytokinin-Responsive Histidine Kinases in Maize. Differential Ligand Preferences and Response to cis-Zeatin

Intracompartmental and Intercompartmental Transcriptional Networks Coordinate the Expression of Genes for Organellar Functions

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