Phosphatidic acid promotes the activation and plasma membrane localization of MKK7 and MKK9 in response to salt stress.

Phosphatidic acid (PA) is a lipid secondary messenger involved in intracellular signaling in eukaryotes. It has been confirmed that PA mediates salt stress signaling by promoting activation of Mitogen-activated Protein Kinase 6 (MPK6) which phosphorylates Na/H antiporter SOS1. However, the MPK6-upstream kinases and their relationship to PA remain unclear.

Copper amine oxidase and phospholipase D act independently in abscisic acid (ABA)-induced stomatal closure in Vicia faba and Arabidopsis.

Recent evidence has demonstrated that both copper amine oxidase (CuAO; EC 1.4.3.