INHIBITION OF ALKALOID ACCUMULATION BY 2,4-D IN CATHARANTHUS-ROSEUS CELL-SUSPENSION IS OVERCOME BY METHYL JASMONATE

In Catharanthus roseus cells (strain C20) 2,4-D exerted a dramatic inh ibition on alkaloid terpenoid precursor availability. In this conditio n, ajmalicine content is less than 2 mu g/gDW. During one subculture t he auxin depletion enhanced greatly the ajmalicine content: about 300 mu g/gDW. In presence of 2,4-D, exogenous methyl jasmonate (MJ) trigge red an ajmalicine accumulation corresponding to 80 % of the one observ ed in a 2,4-D free medium. Thus MJ takes the auxin depletion signal pl ace. In a 2,4-D free medium, inhibition of MJ synthesis by salicylhydr oxamic acid or salicylic acid limits greatly alkaloid content which co uld be restored by exogenous MJ. Thus, MJ can be regarded as a seconda ry messenger in transduction of the auxin depletion signal.