Abstract
Phosphorus limitation leads to a drastic change in membrane lipid composition in plants. Lipidome analysis by liquid chromatography/ ion trap mass spectrometry revealed an accumulation of unknown lipid group in the leaves of A. thaliana by phosphorus limitation. Based on the MS/MS analysis and standard compound, this inducible lipid group was identified as 1,2-diacyl-3-O-alpha-glucuronosylglycerol (GlcADG). During the course of the investigation, an Arabidopsis mutant which accumulated no GlcADG under phosphate-limiting condition, was isolated. Since the mutant was disrupted in a glycosyltransferase gene, this glycosyltransferase were estimated to be involved in the final condensation reaction of diacylglycerol and glucuronic acid. Under phosphate-depleted condition, the mutant showed an enhanced senescence compared with wild type plant, suggesting that GlcADG was involved in the phosphate-limiting growth of A. thaliana. This inducible lipid group was found in leaves of rice, and the level of this lipid also increased by phosphorus limitation, suggesting a conserved physiological significance of this lipid class in plants.
