Changes in primary metabolism in connection with alkaloid biosynthesis in solanaceous cell suspensions: a 13C-NMR study

Abstract

Carbon-13 nuclear magnetic resonance (NMR) spectroscopy was used in the direct comparison of acetate metabolism in suspension cultures of Datura stramonium, an alkaloid producer in vitro, and Nicotiana phumbaginifolia, a non-producer. Growth of cells in the presence of 4 mM [2- 13C] acetate, resulted in a considerably slower uptake of the substrate from medium in D. stramonium than in N. plumbaginifolia. Initial labeling, primarily of the intracellular glutamine and malate pools was observed in N. plumbaginifolia, and putrescine and GABA pools in D. stramonium. The high activity of glutamine synthetase observed in N. plumbaginifolia, which can lead to the non-synthesis of intracellular putrescine by metabolic deviation of glutamate, would be a first explanation for non-biosynthesis of alkaloids for these cell suspensions. On the contrary, the observation of putrescine labeling is in agreement with alkaloid biosynthesis through D. stramonium cell cultures.