Influence of feeding precursors on tropane alkaloid production during an abiotic stress in Datura innoxia transformed roots
2000
Boitel-Conti, M. | Laberche, J.C. | Lanoue, A. | Ducrocq, C. | Sangwan-Norreel, B.S.
The effects of feeding tropane alkaloid precursors in transformed root culture of Datura innoxia Mill. were studied during a stress treatment. The permeabilizing effect of Tween 20 on tropane alkaloid production by hairy root cultures was studied in flasks with different feeding of precursors (L-ornithine, L-arginine, L-phenylalanine, DL-beta-phenyllactic acid, and tropinone). It has been shown that the addition of various precursors alone (0.5 m mol l-1) was ineffective in stimulating hyoscyamine production. In contrast, a short treatment with Tween 20, combined with L-phenylalanine feeding, amplified the level of hyoscyamine released into the medium compared with the Tween treatment alone. Thus, the total hyoscyamine content per flask was increased (+ 40%) compared with the control. When DL-beta-phenyllactic acid (0.5 m mol l-1) was used, this last effect became more pronounced (+ 60%). These results show that permeabilization with Tween modulates tropane alkaloid accumulation by a release of alkaloids into the medium and a restoration of hyoscyamine root content. The simultaneous feeding of DL-beta-phenyllactic acid and tropinone during the Tween treatment gave a similar effect to that obtained with DL-beta-phenyllactic acid and Tween, suggesting that the synthesis of the tropate moiety determines the flux at the level of the esterification of tropine.
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