Profiling Membrane Lipids in Plant Stress Responses

A sensitive approach based on electrospray ionization tandem mass spectrometry has been employed to profile membrane lipid molecular species in Arabidopsis undergoing cold and freezing stresses. Freezing at a sublethal temperature induced a decline in many molecular species of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylglycerol (PG) but induced an increase in phosphatidic acid (PA) and lysophospholipids. To probe the metabolic steps generating these changes, lipids ofArabidopsis deficient in the most abundant phospholipase D, PLDα, were analyzed. The PC content dropped only half as much, and PA levels rose only half as high in the PLDα-deficient plants as in wild-type plants. In…