ABSTRACT
A protocol for the elicitation of capsaicinoids, the pungent principle of peppers, as well as for the biosynthetic intermediaries vanillin and ferulic acid was developed for in vitro cell suspension cultures, and immobilized placentas of Capsicum chinense Jacq. in vitro cultures were exposed to different doses of methyl jasmonate and salicylic acid, which were effective in eliciting specialized metabolism in both of these cultures, resulting in an increased accumulation of the analyzed metabolites.
Subject(s)
Capsicum/metabolism , Tissue Culture Techniques/methods , Cells, Cultured , Metabolome , Plant Cells/metabolism , SuspensionsABSTRACT
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.
Subject(s)
Catharanthus/metabolism , Vinblastine/analogs & derivatives , Vinca Alkaloids/metabolism , Catharanthus/drug effects , Ethylenes/pharmacology , Plant Diseases , Secologanin Tryptamine Alkaloids/metabolism , Seedlings/drug effects , Seedlings/metabolism , Vinblastine/metabolismABSTRACT
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.
