title: An enzyme regulating triacylglycerol composition is encoded by the ROD1 gene of Arabidopsis.
abstract: The polyunsaturated fatty acids (PUFAs) linoleic acid (18:2) and alpha-linolenic acid (18:3) in triacylglycerols (TAG) are major factors affecting the quality of plant oils for human health, as well as for biofuels and other renewable applications. These PUFAs are essential fatty acids for animals and plants, but also are the source of unhealthy trans fats during the processing of many foodstuffs. PUFAs 18:2 and 18:3 are synthesized in developing seeds by the desaturation of oleic acid (18:1) esterified on the membrane lipid phosphatidylcholine (PC) on the endoplasmic reticulum. The reactions and fluxes involved in this metabolism are incompletely understood, however. Here we show that a previously unrecognized enzyme, phosphatidylcholine:diacylglycerol cholinephosphotransferase (PDCT), encoded by the Arabidopsis ROD1 gene, is a major reaction for the transfer of 18:1 into PC for desaturation and also for the reverse transfer of 18:2 and 18:3 into the TAG synthesis pathway. The PDCT enzyme catalyzes transfer of the phosphocholine headgroup from PC to diacylglycerol, and mutation of rod1 reduces 18:2 and 18:3 accumulation in seed TAG by 40%. Our discovery of PDCT is important for understanding glycerolipid metabolism in plants and other organisms, and provides tools to modify the fatty acid compositions of plant oils for improved nutrition, biofuel, and other purposes.
authors.affiliation: Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA.
authors.forename: Chaofu
authors.initials: C
authors.lastname: Lu
authors.forename: Zhanguo
authors.initials: Z
authors.lastname: Xin
authors.forename: Zhonghai
authors.initials: Z
authors.lastname: Ren
authors.forename: Martine
authors.initials: M
authors.lastname: Miquel
authors.forename: John
authors.initials: J
authors.lastname: Browse
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics*; D003433:Crosses, Genetic; D005227:Fatty Acids / Q000032:analysis; D017343:Genes, Plant; D007553:Isotope Labeling; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010713:Phosphatidylcholines / Q000378:metabolism; D010770:Phosphotransferases / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D012639:Seeds / Q000737:chemistry; D020539:Sequence Analysis, Protein; D017855:Transferases (Other Substituted Phosphate Groups) / Q000737:chemistry / Q000235:genetics*; D014280:Triglycerides / Q000096:biosynthesis / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D005227:Fatty Acids; D010713:Phosphatidylcholines; D014280:Triglycerides; D010770:Phosphotransferases; C545204:ROD1 protein, Arabidopsis; D017855:Transferases (Other Substituted Phosphate Groups)