Phospholipases in Nitric Oxide-Mediated Plant Signalling

Abstract

Nitric Oxide (NO) is an important redox-based regulator of cell physiology involved in many signaling processes in plants. The precise molecular mechanism of how NO interacts with or activates different targets is still poorly understood. The polar lipid phosphatidic acid (PA) is another molecule involved in plant signaling. NO and PA have been independently regarded as general, multifunctional stress-signaling molecules in plants. Results obtained in our laboratory revealed that NO induces PA formation during plant-defense responses, stomatal closure, and adventitious root formation. Conversely, during extracellular ATP perception, PA modulates NO production. PA is generated via phospholipase D and phospholipase C in concerted action with diacylglycerol kinase. In this chapter, we discuss how NO might act on PA-generating enzymes as well as their common downstream effectors like Ca2+, reactive oxygen species, kinases, and phosphatases.