Vindoline biosynthesis is transcriptionally blocked in Catharanthus roseus cell suspension cultures

Catharanthus roseus cell cultures were exposed to different conditions in order to induce alkaloid metabolism. The exposure to jasmonate and fungal elicitors resulted in the transcriptional activation of tryptophan decarboxylase and in the accumulation of the monoterpenoid indole alkaloids ajmalicine and catharanthine, but not of vindoline. The inability of the cell cultures to produce vindoline was related to a lack of expression of the desacetoxyvindoline 4-hydroxylase (D4h) gene. Southern blot analysis revealed that D4h gene was not lost in the cell cultures.