CHANGES IN PRIMARY METABOLISM IN CONNECTION WITH ALKALOID BIOSYNTHESIS IN SOLANACEOUS CELL-SUSPENSIONS - A C-13-NMR STUDY

Carbon-13 nuclear magnetic resonance (NMR) spectroscopy was used in th e direct comparison of acetate metabolism in suspension cultures of Da tura stramonium, an alkaloid producer in vitro, and Nicotiana plumbagi nifolia, a non-producer. Growth of cells in the presence of 4 mM [2-C- 13] acetate, resulted in a considerably slower uptake of the substrate from medium in D. stramonium than in N. plumbaginifolia. Initial labe ling, primarily of the intracellular glutamine and malate pools was ob served in N. plumbaginifolia, and putrescine and GABA pools in D. stra monium. The high activity of glutamine synthetase observed in N. plumb aginifolia, which can lead to the non-synthesis of intracellular putre scine by metabolic deviation of glutamate, would be a first explanatio n 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. Copyright (C) 1997 Elsevier Science Ireland Ltd.