Membrane Remodelling in Phosphorus‐Deficient Plants

AbstractPhosphate deficiency results in alterations in the membrane lipid composition of plants, because phospholipids are replaced with nonphosphorous glycolipids. During phosphate deprivation, phospholipids are degraded by phospholipase D (PLD) and phosphatidate phosphatase (PAP), or by phospholipase C (PLC), resulting in the release of diacylglycerol, which is made available for glycolipid synthesis. Free phosphate is employed for essential cellular processes, includingDNAandRNAsynthesis. Expression of genes of galactolipid synthesis is induced in an auxin‐dependent manner during phosphate limitation. The galactolipid digalactosyldiacylglycerol (DGDG) accumulates under phosphate deprivation in plastidial and extraplastidial membranes. Furthermore, the two anionic glycolipids sulfoquinovosyldiacylglycerol and glucuronosyldiacylglycerol accumulate in the chloroplast, as surrogates for phosphatidylglycerol. Further phosphate‐free glycolipids (glucosylceramide, sterol glucosides, acylated sterol glucosides) accumulate in the plasma membrane under phosphate deprivation. The replacement of phospholipids with glycolipids during phosphate starvation has already been established in some bacteria, and therefore represents an ancient, essential adaptation process to low‐phosphate conditions in the environment.