title: Expression of rapeseed microsomal lysophosphatidic acid acyltransferase isozymes enhances seed oil content in Arabidopsis.
abstract: In higher plants, lysophosphatidic acid acyltransferase (LPAAT), located in the cytoplasmic endomembrane compartment, plays an essential role in the synthesis of phosphatidic acid, a key intermediate in the biosynthesis of membrane phospholipids in all tissues and storage lipids in developing seeds. In order to assess the contribution of LPAATs to the synthesis of storage lipids, we have characterized two microsomal LPAAT isozymes, the products of homoeologous genes that are expressed in rapeseed (Brassica napus). DNA sequence homologies, complementation of a bacterial LPAAT-deficient mutant, and enzymatic properties confirmed that each of two cDNAs isolated from a Brassica napus immature embryo library encoded a functional LPAAT possessing the properties of a eukaryotic pathway enzyme. Analyses in planta revealed differences in the expression of the two genes, one of which was detected in all rapeseed tissues and during silique and seed development, whereas the expression of the second gene was restricted predominantly to siliques and developing seeds. Expression of each rapeseed LPAAT isozyme in Arabidopsis (Arabidopsis thaliana) resulted in the production of seeds characterized by a greater lipid content and seed mass. These results support the hypothesis that increasing the expression of glycerolipid acyltransferases in seeds leads to a greater flux of intermediates through the Kennedy pathway and results in enhanced triacylglycerol accumulation.
authors: Laboratoire Génome et Développement des Plantes, CNRS-UP-IRD UMR 5096, Université de Perpignan, 66860 Perpignan, France.
authors: Sylvie
authors: S
authors: Maisonneuve
authors: Jean-Jacques
authors: JJ
authors: Bessoule
authors: René
authors: R
authors: Lessire
authors: Michel
authors: M
authors: Delseny
authors: Thomas J
authors: TJ
authors: Roscoe
mesh_terms: D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029741:Brassica rapa / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D018744:DNA, Plant / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010938:Plant Oils / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012639:Seeds / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D014280:Triglycerides / Q000096:biosynthesis
chemical_list: D018744:DNA, Plant; D007527:Isoenzymes; D010938:Plant Oils; D010940:Plant Proteins; D014280:Triglycerides; D000217:Acyltransferases; C018764:2-acylglycerophosphate acyltransferase