Quantitative Profiling of Polar Glycerolipid Species from Organs of Wild-Type Arabidopsis and a PHOSPHOLIPASE Dα1 Knockout Mutant

Lipid profiling is a targeted metabolomics platform that provides a comprehensive analysis of lipid species with high sensitivity. Profiling based on electrospray ionization tandem mass spectrometry (ESI-MS/MS) provides quantitative data and is adaptable to high throughput analyses. Here we report the profiling of 140 apparent molecular species of polar glycerolipids in Arabidopsis leaves, flower stalks, flowers, siliques, roots, and seeds. Considerable differences in lipid species occur among these organs, providing insights into the different lipid metabolic activities in a specific organ. In addition, comparative profiling between wild-type and a knockout mutant pldα1 (locus ID: AT3G15730) provides insight into the metabolic function of phospholipase D (PLD) in different organs. PLDα1 contributes significantly to phosphatidic acid (PA) levels in roots, seeds, flowers, and flower stalks, but little to basal PA levels in siliques and leaves. In seeds of the pldα1 mutant plants, levels of PA, lysophosphatidylcholine, and lysophosphatidylethanolamine were significantly lower than those of wild-type seeds, suggesting a role for PLDα1 in membrane lipid degradation in seeds.