THE KINETICS OF TAXOID ACCUMULATION IN CELL-SUSPENSION CULTURES OF TAXUS FOLLOWING ELICITATION WITH METHYL JASMONATE

Cell suspension cultures of Taxus canadensis and Taxus cuspidata rapid ly produced paclitaxel (Taxol) and other taxoids in response to elicit ation with methyl jasmonate. By optimizing the concentration of the el icitor, and the timing of elicitation, we have achieved the most rapid accumulation of paclitaxel in a plant cell culture, yet reported. The greatest accumulation of paclitaxel occurred when methyl jasmonate wa s added to cultures at a final concentration of 200 mu M on day 7 of t he culture cycle. The concentration of paclitaxel increased in the ext racellular (cell-free) medium to 117 mg/day within 5 days following el icitation, equivalent to a rate of 23.4 mg/L per day. Paclitaxel was o nly one of many taxoids whose concentrations increased significantly i n response to elicitation. Despite the rapid accumulation and high con centration of paclitaxel, its concentration never exceeded 20% of the total taxoids produced in the elicited culture. Two other taxoids, 13- acetyl-9-dihydrobaccatin III and baccatin VI, accounted for 39% to 62% of the total taxoids in elicited cultures. The accumulation of baccat in III did not parallel the pattern of accumulation for paclitaxel. Ba ccatin III continued to accumulate until the end of the cu Itu re cycl e, at which point most of the cells in the culture were dead, implying a possible role as a degradation product of taxoid biosynthesis, rath er than as a precursor. (C) 1999 John Wiley & Sons, Inc. Biotechnol Bi oeng 62: 97-105, 1999.