Induction of ABA 8'-hydroxylase by (+)-S-,(-)-R- and 8',8',8'-trifluoro-S-abscisic acid in suspension cultures of potato and Arabidopsis

Suspension cultures of potato and Arabidopsis were incubated with 50 mu M of (+)-ABA and (-)-ABA for 3 hr. These pretreatments were found to increase the rate, by two- to seven-fold, of formation of [H-2(6)] phaseic acid (PA) from [H-2(6)] ABA, applied in a subsequent incubation. Pretreatment with trifluoro-ABA had a higher efficacy, increasing the rate of conversion 15-fold. Suspension culture cells that had been dehydrated and then rehydrated in the presence of [H-2(6)] ABA displayed a much lower enhancement of PA formation. We conclude that ABA induces its own oxidative catabolism in suspension cultures. (C) 1997 Elsevier Science Ltd. All rights reserved.