Role of ABA in ethylene-independent Iris flower senescence

This project aims at investigating the role of ABA in ethylene-independent flower senescence. Our hypothesis is that ABA (abscisic acid) as a developmental factor activates PP2C (protein phosphatase 2C), an ABA signalling regulator. Activated PP2C probably dephosphorylates an interacting component essential for ABA signalling and turns on the pathway for “death protein” synthesis, which activates hydrolytic enzymes like proteases, leading to PCD and floral death. By using flag petal rims of cut Iris flowers, we have gathered physiological and molecular evidences suggesting a direct role of ABA in upregulating the early steps of ethylene-independant petal senescence, and “Blue Magic” Iris could serve as a good model plant for studying age-dependent, ethylene-independant senescence of flowers, some of which are food crops.