Attempts to produce solasodine in callus and suspension cultures of Solanum mauritianum Scop.

Abstract

Callus cultures of Solarium mauritianum Stop. were initiated from green berry explants on a hormone-free Murashige and Skoog (1962) medium excluding glycine, and containing 0.1 g L-' myo-inositol and 3% sucrose. Such cultures contained 10.08 f 0.59 pg g-' DW of solasodine, which is equivalent to that in the leaves of mature S. mauritianum plants, but far less than that extracted from the green berries (185 pg g-' DW). In vitro solasodine productivity could be increased by reducing the strength of the medium by half, substituting 3% glucose for 3% sucrose as carbon source, or by the addition of certain combinations of BA and NAA. Phosphate limitation and alterations in the carbon:nitrogen ratio were not able to increase solasodine productivity. Suspension cultures of S. mauritianum were initiated and maintained in a Murashige and Skoog (1962) medium with the RT vitamins of Khanna and Staba (1968), 0.1 g L-' myo-inositol, 3% sucrose and 1 mg L-' 2,4-D. No solasodine was detectable in these cultures, or slight modifications thereof.Abbreviations: BA -benzyladenine; NAA -naphthaleneacetic acid; 2,4-D -2,4-dichlorophenoxyacetic acid; MS -Murashige and Skoog's (1962) medium.

Initiation of and solasodine production in hairy root cultures of Solanum mauritianum Scop.

“…In the most productive medium, the solasodine level was lower than the 184 pg g-' DW previously recorded in the green berries of S. mauritianum, using the same extraction and detection protocol, but was far higher than that recorded in the roots of an intact plant (30 pg g-t DW) [6]. It was also far greater than that of any callus or suspension culture of the same species [6].…”

“…It was also far greater than that of any callus or suspension culture of the same species [6]. Overall, taking into account the ease with which the hairy roots could be continuously subcultured, the rate of growth in the full-strength medium containing 3% sucrose and the high levels of solasodine present, these cultures do appear to provide a favourable system for the potential in vitro synthesis of solasodine.…”

“…Previously, solasodine levels in callus cultures of S. muuritiunum were found to be increased if the strength of the medium was reduced by half or if 3% glucose was substituted for the usual 3% sucrose in the medium [6]. Therefore, hairy roots were subcultured onto media modified in the same manner.…”

“…The samples were extracted and purified as previously described for callus and suspension cultures of S. mauritianum [6]. Solasodine levels were determined by HPLC [7].…”

“…Those that have been successfully transformed include the potato, Solanum tuberosum [21, 22, 281 and Solanum nigrum [18, 301. We are not aware of any reports of Solanum species in which hairy root cultures have been examined as a means of solasodine production. We have previously examined factors affecting the solasodine content of callus and suspension cultures of S. mauritianum [6], a widespread weed in South Africa [32]. We now report on the production of solasodine in hairy root cultures of this species.…”