TAXOL PRODUCTION IN NODULE CULTURES OF TAXUS

The in vitro synthesis of secondary compounds from plants is one sourc e of scarce and valuable phytopharmaceuticals. Often, some level of ce llular or tissue differentiation is needed for the biosynthesis of man y of these important compounds. Nodule cultures, consisting of cohesiv e multicellular units displaying a high degree of differentiation, wer e initiated from cultured needles of seven Taxisu cultivars (Taxus cus pidata, Taxus x media 'Hicksii', Taxus x hunnewelliana 'Richard Horsey ', Taxus x media 'Dark. Green Spreader', Taxus x media 'L. C. Bobbick, and Taxus brevifolia). Under normal semicontinuous perfusion culture conditions (bimonthly refreshments to yield 0.2% sucrose), only trace amounts of taxol were detected from Taxus nodule cultures, However, wi th an elevated sucrose level (0.5% or 1.0%), taxol production was enha nced in T. cuspidata nodules to approximately 12 mu g taxol/g nodule d ry weight (dw). Stimulation of taxol production by elevated sucrose le vels occurred even in the absence of other nutrients. The effect of in creased sucrase on taxol induction does not appear to be due to an osm otic effect in the medium, suggesting that the increase in taxol produ ction may be correlated with a metabolic process within the nodules. A lthough sucrose had a significant effect on taxol production, taxane p recursors or elicitors of terpenes, as well as other plant secondary m etabolites, had no effect on the production of taxol from these cultur es. In addition to taxol, the higher sucrose levels also induced the p roduction of 7-epi)-10-deacetyltaxol, cephalomannine, and 7-epi-10-dea cetylcephalomannine, so that total content of these taxanes equaled ap proximately 39 mu g taxane/g dw nodules.