Differential enhancement of benzophenanthridine alkaloid content in cell suspension cultures of Sanguinaria canadensis under conditions of combined hormonal deprivation and fungal elicitation.

ABSTRACT

An elicitation protocol, resulting in the accumulation of sanguinarine in suspension cultures of Papaver bracteatum, was assessed for induction of the same alkaloid in Sanguinaria canadensis. Although only a trace constituent of P. bracteatum plants, sanguinarine is a major alkaloid (1-3% dry wt) of S. canadensis rhizomes. By combining hormonal deprivation for various intervals and a 3-day fungal (Verticillium dahliae) elicitation, benzophenanthridine alkaloid accumulation was induced in S. canadensis cell suspensions. Chelirubine content increased (0.1-1.3% dry wt) consistently in elicited cell cultures while chelerythrine (0.01-0.10% dry wt) and sanguinarine (0-0.02% dry wt) levels were considerably less. Alkaloid accumulation always occurred upon removal of hormone but only at certain time intervals in the log phase upon fungal elicitation. Levels of dopamine, a precursor of the alkaloids, fluctuated over the incubation period, but displayed a 2- to 6-fold increase in cell suspensions grown without hormone. In some experiments dopamine accumulated to levels > 20% dry wt, and these increases were enhanced by the addition of fungal elicitor. Although the same fungal elicitor induces benzophenanthridines in taxonomically related S. canadensis and P. bracteatum, it did not elicit the accumulation of the same alkaloid in the two different plant cultures.