Patatin-related phospholipase pPLAIIIδ increases seed oil content with long-chain fatty acids in Arabidopsis

Abstract

The release of fatty acids from membrane lipids has been implicated in various metabolic and physiological processes, but in many cases, the enzymes involved and their functions in plants remain unclear. Patatin-related phospholipase As (pPLAs) constitute a major family of acyl-hydrolyzing enzymes in plants. Here, we show that pPLAIIId promotes the production of triacylglycerols with 20- and 22-carbon fatty acids in Arabidopsis (Arabidopsis thaliana). Of the four pPLAIIIs (a, b, g, d), only pPLAIIId gene knockout results in a decrease in seed oil content, and pPLAIIId is most highly expressed in developing embryos. The overexpression of pPLAIIId increases the content of triacylglycerol and 20- and 22-carbon fatty acids in seeds with a corresponding decrease in 18-carbon fatty acids. Several genes in the glycerolipid biosynthetic pathways are up-regulated in pPLAIIId-overexpressing siliques. pPLAIIId hydrolyzes phosphatidylcholine and also acyl-coenzyme A to release fatty acids. pPLAIIId-overexpressing plants have a lower level, whereas pPLAIIId knockout plants have a higher level, of acyl-coenzyme A than the wild type. Whereas seed yield decreases in transgenic plants that ubiquitously overexpress pPLAIIId, seed-specific overexpression of pPLAIIId increases seed oil content without any detrimental effect on overall seed yield. These results indicate that pPLAIIId-mediated phospholipid turnover plays a role in fatty acid remodeling and glycerolipid production. © 2013 American Society of Plant Biologists. All Rights Reserved.