Alkaloid metabolism in wounded Catharanthus roseus seedlings

The effect of mechanical wounding on alkaloid metabolism was analyzed in Catharanthus roseus seedlings. Wounding induced an increase in ajmalicine accumulation, whereas catharanthine remained unaffected. A positive dual effect on vindoline was noticed. Short and mid-term effects were detected between 12 and 24 h after mechanical damage was inflicted, and apparently resulted from the accelerated transformation of the tabersonine intermediaries to vindoline. Long-term effects involved a generalized increase in carbon flux towards alkaloid synthesis. Exposure to ethylene (1 ppm) produced similar results to those observed in wounded seedlings, suggesting that it might be mediating the wound-induced increase in alkaloid synthesis. No synergistic or additive effects were observed when wounded seedlings were exposed to ethylene or jasmonate.