The octadecanoid pathway leads to the production of jasmonic acid which is an important signaling molecule in plants. Exogenously added jasmonic acid or methyl jasmonate has been shown to increase production of the terpenoid indole alkaloids (TIAs) in Catharanthus roseus plants, hairy roots, and cell suspension cultures. Two pharmaceutically important TIAs are the anticancer drugs vinblastine and vincristine which are produced in small quantities within the plant. Our aim is to increase the production of these compounds within C. roseus hairy roots.

The role of the octadecanoid pathway for production of TIAs differs between C. roseus cell suspension cultures and whole plants. In cell suspension cultures, inhibition of the octadecanoid pathway leads to a decrease in TIA production which can be restored when methyl jasmonate is added. Similarly addition of early precursors of the octadecanoid pathway leads to an increase in TIA production (Gantet et al. 1998. Plant Cell Physiology. 39(2): 220-225). In seedlings inhibition of the octadecanoid pathway or the addition of early precursors did not change TIA production (Aerts et al. 1996 Phytochemistry 42(2): 417-422).

The aim of this study is to determine the role of the octadecanoid pathway on TIA production in C. roseus hairy roots. We will discuss the effects of various octadecanoid precursors and inhibitors on TIA production in C. roseus hairy roots during late exponential growth phase. Our results suggest that hairy roots behave like whole plants in that inhibition of the octadecanoid pathway or the addition of early octadecanoid precursors did not change TIA production.