Effects of Nicotine Precursors on Nicotine Content in Callus Cultures of Burley Tobacco Alkaloid Lines1
- R. D. Miller,
- G. B. Collins and
- D. L. Davis2
Callus cultures of four hurley tobacco (Nicotiana tabacum L.) genotypes differing in alkaloid content were grown on three basal media supplemented with compounds known to be intermediates in the biosynthesis of nicotine. The effects of these compounds on nicotine concentrations in the calli were evaluated to determine if one or more of the compounds were limiting to nicotine synthesis in the low alkaloid genotypes. In general, the supplemental compounds tested reduced nicotine concentrations in the calli of all four alkaloid genotypes. Callus cultures of high alkaloid lines underwent more extensive root and shoot differentiation than did cultures of low alkaloid genotypes. However, genotypic and treatment effects were unaffected by state of differentiation present in the calli. Although several of the treatments had a significant effect on the nicotine content of the calll, none eliminated differences between dominant and recessive alleles at both loci known to control nicotine levels in tobacco. Nicotine levels detected in all control and treatment cultures of the four alkaloid genotypes were proportional to nicotine concentration in the respective intact plants. The results of the present study suggest that differences in nicotine concentrations among callus cultures of the four alkaloid genotypes are not due to a biosynthetic block in the formation of the pyridine or pyrrolidine rings of nicotine.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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