Tobacco cells transformed with the fission yeast Spcdc25 mitotic inducer display growth and morphological characteristics as well as starch and sugar status evocable by cytokinin application
Language English Country France Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
18550380
DOI
10.1016/j.plaphy.2008.04.017
PII: S0981-9428(08)00054-5
Knihovny.cz E-resources
- MeSH
- Cell Cycle drug effects genetics physiology MeSH
- Cytokinins metabolism pharmacology MeSH
- Fungal Proteins genetics physiology MeSH
- Plants, Genetically Modified drug effects genetics metabolism MeSH
- Cells, Cultured MeSH
- Cell Cycle Proteins genetics physiology MeSH
- ras-GRF1 genetics physiology MeSH
- Gene Expression Regulation, Plant drug effects MeSH
- Carbohydrates analysis MeSH
- Schizosaccharomyces genetics MeSH
- Starch analysis MeSH
- Nicotiana cytology genetics growth & development MeSH
- Transformation, Genetic MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Cytokinins MeSH
- Fungal Proteins MeSH
- Cell Cycle Proteins MeSH
- ras-GRF1 MeSH
- Carbohydrates MeSH
- Starch MeSH
In plants, the G2/M control of cell cycle remains an elusive issue as doubts persist about activatory dephosphorylation--in other eukaryotes provided by CDC25 phosphatase and serving as a final all-or-nothing mitosis regulator. We report on the effects of tobacco (Nicotiana tabacum L., cv. Samsun) transformation with fission yeast (Schizosaccharomyces pombe) cdc25 (Spcdc25) on cell characteristics. Transformed cell suspension cultures showed higher dry mass accumulation during the exponential phase and clustered more circular cell phenotypes compared to chains of elongated WT cells. Similar cell parameters, as in the transformants, can be induced in WT by cytokinins. Spcdc25 cells, after cytokinin treatment, showed giant cell clusters and growth inhibition. In addition, Spcdc25 expression led to altered carbohydrate status: increased starch and soluble sugars with higher sucrose:hexoses ratio, inducible in WT by cytokinin treatment. Taken together, the Spcdc25 transformation had a cytokinin-like effect on studied characteristics. However, endogenous cytokinin determination revealed markedly lower cytokinin levels in Spcdc25 transformants. This indicates that the cells sense Spcdc25 expression as an increased cytokinin availability, manifested by changed cell morphology, and in consequence decrease endogenous cytokinin levels. Clearly, the results on cell growth and morphology are consistent with the model of G2/M control including cytokinin-regulated activatory dephosphorylation. Nevertheless, no clear link is obvious between Spcdc25 transformation and carbohydrate status and thus the observed cytokinin-like effect on carbohydrate levels poses a problem. Hence, we propose that Spcdc25-induced higher CDK(s) activity at G2/M generates a signal-modifying carbohydrate metabolism to meet high energy and C demands of forthcoming cell division.
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