Steroidal glycoalkaloids in cell and shoot teratoma cultures of Solanum dulcamara

Bittersweet (Solanum dulcamara L., Solanaceae) is of interest as a source of steroidal alkaloids for the commercial production of hormones. Since glycoalkaloid production is positively correlated to differentiation, tumor and teratoma cultures of the soladulcidine chemotype were established by transformation with Agrobacterium tumefaciens. A newly developed HPLC-system, which allowed separation and sensitive quantitation of the glycoalkaloids soladulcidine-tetraoside, solamargine and solasonine, was used to analyse glycoalkaloid profiles in plants and cultures. Tumors and teratoma were characterized by a shift in their alkaloid pattern from soladulcidine tetraoside to the solasodine glycosides solamargine and solasonine. Shoot teratoma showed a total glycoalkaloid content of 1% dw, which is about fivefold higher than in the source plant. A regenerated plant retained the altered alkaloid spectrum; the levels, however, equalled those of the source plant. From the alteration of alkaloid pattern in the transformed cultures suggestions can be made concerning the biosynthetic pathway. Completion of the biosynthesis of the aglycone is likely to be complete before glycosylation occurs.