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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- 2.Alberts AW, Chen J, Kuron G, Hunt V, Huff J, Hoffman C, Rothrock J, Lopez M, Joshua H, Harris E, Patchett A, Monagan R, Currie S, Stapley E, Albers-Schönberg G, Hensens O, Hirschfield J, Hoogsteen K, Liesch J, Springer J (1980) Mevinolin: a highly potent competitive inhibitor of hydroxymethylglutaryl-coenzyme A reductase and a cholesterol-lowering agent. Proc Natl Acad Sci USA 77: 3957–3961PubMedCrossRefGoogle Scholar
- 4.Bach TJ, Lichtenthaler HK (1982) Mevinolin: a highly specific inhibitor of microsomal 3-hydroxy-3-methylglutaryl-coenzyme A reductase of radish plants. Z. Naturforsch 37c: 46–50Google Scholar
- 6.Bach TF, Lichtenthaler HK (1983) Mechanisms of inhibition by mevinolin (MK803) of microsome-bound radish and of partially purified yeast HMG-CoA reductase (EC126.96.36.199). Z. Naturforsch 38c: 212–219Google Scholar
- 11.Hata S, Takagishi H, Kouchi H (1987) Variation in the content and composition of sterols in alfalfa seedlings treated with compactin (ML-236B) and mevalonic acid. Plant Cell Physiol 28: 709–714Google Scholar
- 12.Letham DS, Higgins TJV, Goodwin PB, Jacobsen JV (1978) Phytohormones in retrospect. In DS Letham, PB Goodwin, TJV Higgins, eds, Phytohormones and Related Compounds: A Comprehensive Treatise, Vol 1. Elsevier/North-Holland, New York, pp 1–27Google Scholar
- 15.Miller CO (1968) Biochemistry and Physiology of Plant Growth Substances. Runge, Ottawa, pp 33–45Google Scholar
- 18.Noodén LD, Guiamét JJ, Singh S, Letham DS, Tsuji J, Schneider MJ (1990) Hormonal control of senescence. In RP Pharis, SB Rood, eds, Plant Growth Substances. Springer-Verlag, Berlin, pp 537–546Google Scholar