ADVANTAGES AND LIMITATIONS IN THE USE OF HAIRY ROOT CULTURES FOR THE PRODUCTION OF TROPANE ALKALOIDS - USE OF ANTI-AUXINS IN THE MAINTENANCE OF NORMAL ROOT MORPHOLOGY

Brugmansia candida hairy roots, obtained by infection with Agrobacteri um rhizogenes LBA 9402, exhibit, after subculturing in liquid media, a tendency towards dedifferentiation. It has been found that the follow ing strategies can be applied to inhibit this dedifferentiation and pr eserve normal root morphology: (a) lowering both the mineral and sucro se concentration in the media employed so as to diminish osmotic stres s (a condition to which these roots appear to be particularly suscepti ble); (b) employing antiauxins in appropriate concentrations; and (c) maintaining the hairy roots on solid media prior to use in production processes in liquid media. The first strategy suggested does not favor alkaloid productivity, but in this case a two-step method could be at tempted: biomass with normal root morphology could be obtained in a fi rst stage using low sucrose concentrations, and in a second stage, suc rose could be increased in order to achieve higher productivity. In al l the clones of B. candida obtained, alkaloid production was biased to wards scopolamine.