Somaclonal Variation of Scopolamine Content in Protoplast-Derived Cell Culture Clones of Hyoscyamus muticus

Abstract

We have established clonal cell cultures derived from protoplasts of haploid and diploid Hyoscyamus muticus L. var. Gatersleben (Solanaceae) plants. The scopolamine content of plants and the clones was determined by sensitive enzyme- and radioimmunoassay. Variation in scopolamine content was significant among whole plants. Scopolamine content in haploid plants was found to be clearly 2-3 times higher than in diploid ones. The same difference was observed between the cell culture clones derived from haploid plants compared to the clones derived from diploids. The mean content of scopolamine in cultured cell clones was much smaller than in plants, usually by about a factor of 200. There was also substantial somaclonal variation in scopolamine content of various clones derived from individual haploid and diploid plants. Possible sources and reasons for this variation were tested.

During the time course of the growth of the callus clones maximal scopolamine production occurred after 28 days of incubation. Scopolamine content was observed to be independent of the visible characteristics of the clones. Among 2581 (X-ray, UV-light and MNNG) mutagenised clones no clone could be found which produced higher scopolamine levels than non-mutagenised clones. Scopolamine production varied with passage number. We found that intermediate-producing clones had increased scopolamine levels at the 2nd to the 4th passage but after ten passages reverted to the initial level.

We conclude there is somaclonal variation of secondary metabolite production.