Lovastatin Induces Cytokinin Dependence in Tobacco Cultures
The mevalonate pathway participates in the formation of cytokinins, abscisic acid, gibberellins, ubiquinones, plastoquinones, dolichols, sterols, carotenoids, chlorophylls, and numerous other isoprenoids in plant cells. The first committed step in this pathway is the irreversible reduction of 3-hydroxy-3-methylglutaryl CoA (HMG CoA) to mevalonate, a reaction that is catalyzed by HMG CoA reductase. We have studied the effects of a potent HMG CoA reductase inhibitor (lovastatin) on growth of a cytokinin-independent Nicotiana tabacum cell line and found that growth inhibition at low concentrations of inhibitor is reversed by various cytokinins. However, cytokinin analogs with little or no cytokinin activity do not restore growth to lovastatin-treated cells. These results are consistent with the hypothesis that cytokinin biosynthesis is more sensitive to lovastatin than the biosynthesis of other essential isoprenoid compounds in tobacco cells.
KeywordsMevalonate Pathway Mevalonic Acid Aspergillus Terreus Cytokinin Biosynthesis Tobacco Culture
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