Induction of secondary metabolism in grape cell cultures by jasmonates

The use of a genetic approach to study the biosynthetic pathways leading to the production of secondary metabolites in grapes is difficult given the long generation times and difficulty in transforming this species. In the present study, GC/MS and microarray experiments were used to identify compounds produced in grape cell cultures in response to jasmonates and to examine the expression of genes from pathways that produce these secondary metabolites. Methyl jasmonate (MeJA) and jasmonic acid (JA) treatments resulted in the production of at least 25 compounds with sesquiterpene-like mass spectra in the cell cultures. A significantly greater amount of proanthocyanidins was produced in the MeJA-treated cell cultures compared with controls and stilbene biosynthesis was induced in both MeJA- and JA-treated cells. Salicylic acid (SA) suppressed the MeJA-associated increase in sesquiterpenes and proanthocyanidins, but SA did not suppress the stilbene production induced by MeJA treatment. The mechanism by which jasmonates induced secondary metabolite production in cultured grape cells varied depending on the pathway. The increased production of proanthocyanidins and stilbenes was associated with the induction of all of the genes in associated biosynthesis pathways, including those involved in the production of phenylalanine, whereas increased sesquiterpene synthesis was linked to the induction of certain genes from relevant biosynthesis pathways.