ACCUMULATION AND METABOLISM OF MEDICARPIN AND MAACKIAIN MALONYLGLUCOSIDES IN ELICITED CHICKPEA (CICER-ARIETINUM L) CELL-SUSPENSION CULTURES

Upon elicitation, chickpea cell suspension cultures accumulate the two pterocarpan phytoalexins, medicarpin and maackiain, and their corresponding 3-O-glucoside-6'-O-malonates. Both pterocarpan conjugates are also constitutive metabolites of the cell cultures. The ratio of accumulating aglyca to conjugates depends on the intensity of the elicitor effect. Low or moderate amounts of elicitor favour conjugate formation whereas high doses predominantly lead to aglycone formation. The effect of different elicitor doses could also be observed at the enzymatic level. The activities of the enzymes involved in pterocarpan conjugation and hydrolysis correlate with the changing ratio of accumulating aglyca and conjugates. The pterocarpan phytoalexins are not totally synthesized de-novo because elicitation leads to a consumption of preformed pterocarpan conjugates for phytoalexin aglyca formation.