NECESSITY OF A FUNCTIONAL OCTADECANOIC PATHWAY FOR INDOLE ALKALOID SYNTHESIS BY CATHARANTHUS-ROSEUS CELL-SUSPENSIONS CULTURED IN AN AUXIN-STARVED MEDIUM

The effect of methyl jasmonate (mJA), jasmonic acid and traumatic acid , derivatives of the octadecanoic pathway, on the production of alkalo ids by cell suspension cultures of Catharanthus roseus L. (G) Don was investigated, Cells cultured in the presence of auxin (m-cells) did no t accumulate alkaloids, The addition of exogenous mJA to m-cells resto red the ability to produce alkaloids, In cells cultured in a 2,4-D-sta rved medium (p-cells), exogenous mJA greatly increased alkaloid produc tion, Similar data were obtained for jasmonic acid, In contrast, traum atic acid had no effect on alkaloid production, The sensitivity of cel l suspension cultures to exogenous mJA was restricted to the first fou r days of subculture corresponding to the active growth phase, whereas the alkaloid accumulation occurred only during the stationary phase o f the subculture (days 6 to 10), When p-cells were treated with octade canoic pathway inhibitors, the ability to produce alkaloids was strong ly reduced, The addition of exogenous mJA always restored the ability to produce alkaloids, These data suggest that in response to auxin dep letion, endogenous mJA could be produced and act by linking physiologi cal events thus leading to alkaloid biosynthesis activation.