Alkaloid biosynthesis in Papaver sp. cells in culture and during organogenesis

In vitro cell cultures of two Papaver species, P. somniferum and P. bracteatum initiated from mature seeds were screened for their ability to produce alkaloids. Protocols for callus induction, somatic embryogenesis and organogenesis were established. The alkaloid contents were analysed by high-performance-liquid chromatography, thin-layer chromatography and spectrophotometric assays. Undifferentiated callus produced small amounts of sanguinarine, which increased with the degree of tissue differentiation. Embryogenic calli were maintained in culture for more than 2 years, retaining a high regeneration capability. Thin-layer chromatography analysis revealed variations in alkaloid spectrum between parallel cell lines. The morphinan alkaloid, thebaine, was found to be accumulated exclusively in morphogenous strains of P. bracteatum, and morphine was the major alkaloid in the spectrum of P. somniferum dedifferentiated callus. Regenerant plants synthesized thebaine and sanguinarine at the same level as juvenile plants grown from P. bracteatum seeds. We revealed differences in the ability to produce different types of alkaloids: seed-derived plants were able to accumulate thebaine while undifferentiated primary cell cultures produced only sanguinarine. The production of either sanguinarine and morphinan alkaloids are found in regenerants showing that both metabolic pathways were active in young plantlets.