XVI International Botanical Congess

Three types of phospholipases (PL), PLC, PLD, and PLA2 have been proposed to play important roles in plant signal transduction. PLC generates diacylglycerol and a phosphorylated head group such as inositolpolyphosphates. PLA2 produces lysophospholipid and a free fatty acid, and PLD generates phosphatidic acid and a free alcoholic head group. Many of these phospholipase-produced metabolites serve as messengers in signaling cascades, and they often network with one another in mediating cellular functions. These interactions of phospholipases are exemplified by the recent studies on the activation and function of PLD. PLD is a family of heterogenous enzymes, which are regulated differently by inositolphospholipids and calcium. Activation and suppression of PLD can alter the activities of the other lipid-signaling enzymes and affect the production and function of several lipid mediators, including phosphatidic acid, diacylglycerol, and oxylipins.