• Medientyp: E-Artikel
  • Titel: Increased sterol biosynthesis in tobacco calli resistant to a triazole herbicide which inhibits demethylation of 14α-methyl sterols
  • Beteiligte: Schaller, Hubert; Maillot-Vernier, Pascale; Belliard, Geneviève; Benveniste, Pierre
  • Erschienen: Springer-Verlag, 1992
  • Erschienen in: Planta
  • Sprache: Englisch
  • ISSN: 0032-0935; 1432-2048
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  • Beschreibung: <p>The γ-keto triazole derivative 4,4-dimethyl-1-(2-methoxyphenyl)-1-(1,2,4-triazol-1-yl)-1-penten-3-one is toxic to Nicotiana tabacum L. cv. Xanthi plants or cell cultures. Analysis of the sterol composition of treated wild-type plant material demonstrates that this herbicide is an inhibitor of the C-14α-methyl demethylation process in sterol biosynthesis. Selection experiments, consisting of screening large populations of microcalli derived from UV-mutagenized tobacco protoplasts for resistance to a lethal dose (1 mg·l-1) of the γ-keto triazole, have resulted in the recovery of two groups of resistant calli. In the first group, selected calli show a sterol composition in the absence or presence of the inhibitor very similar to that of wild-type sensitive calli, whereas in the second group the main feature of the selected calli is a new sterol profile. These calli present an overproduction of sterols with a concomitant esterification of overproduced metabolites, just as it was demonstrated for calli previously selected in our laboratory for resistance to LAB 170250F, a triazole fungicide (Maillot-Vernier et al., 1991, Mol. Gen. Genet. 231, 33—40).</p>