ABA-dependent amine oxidases-derived H2O2 affects stomata conductance.

Recently we showed that ABA is at least partly responsible for the induction of the polyamine exodus pathway in Vitis vinifera plants. Both sensitive and tolerant plants employ this pathway to orchestrate stress responses, differing between stress adaptation and programmed cell death. Herein we show that ABA is an upstream signal for the induction of the polyamine catabolic pathway in Vitis vinifera. Thus, amine oxidases are producing H2O2 which signals stomata closure. Moreover, the previously proposed model for the polyamine catabolic pathway is updated and discussed.