title: Comparative transcriptome analysis of three oil palm fruit and seed tissues that differ in oil content and fatty acid composition.
abstract: Oil palm (Elaeis guineensis) produces two oils of major economic importance, commonly referred to as palm oil and palm kernel oil, extracted from the mesocarp and the endosperm, respectively. While lauric acid predominates in endosperm oil, the major fatty acids (FAs) of mesocarp oil are palmitic and oleic acids. The oil palm embryo also stores oil, which contains a significant proportion of linoleic acid. In addition, the three tissues display high variation for oil content at maturity. To gain insight into the mechanisms that govern such differences in oil content and FA composition, tissue transcriptome and lipid composition were compared during development. The contribution of the cytosolic and plastidial glycolytic routes differed markedly between the mesocarp and seed tissues, but transcriptional patterns of genes involved in the conversion of sucrose to pyruvate were not related to variations for oil content. Accumulation of lauric acid relied on the dramatic up-regulation of a specialized acyl-acyl carrier protein thioesterase paralog and the concerted recruitment of specific isoforms of triacylglycerol assembly enzymes. Three paralogs of the WRINKLED1 (WRI1) transcription factor were identified, of which EgWRI1-1 and EgWRI1-2 were massively transcribed during oil deposition in the mesocarp and the endosperm, respectively. None of the three WRI1 paralogs were detected in the embryo. The transcription level of FA synthesis genes correlated with the amount of WRI1 transcripts and oil content. Changes in triacylglycerol content and FA composition of Nicotiana benthamiana leaves infiltrated with various combinations of WRI1 and FatB paralogs from oil palm validated functions inferred from transcriptome analysis.
authors.affiliation: Institut de Recherche pour le Développement, Unité Mixte de Recherche Diversité, Adaptation et Développement des Plantes, BP 64501, 34394 Montpellier, France. stephane.dussert@ird.fr
authors.forename: Stéphane
authors.initials: S
authors.lastname: Dussert
authors.forename: Chloé
authors.initials: C
authors.lastname: Guerin
authors.forename: Mariette
authors.initials: M
authors.lastname: Andersson
authors.forename: Thierry
authors.initials: T
authors.lastname: Joët
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Tranbarger
authors.forename: Maxime
authors.initials: M
authors.lastname: Pizot
authors.forename: Gautier
authors.initials: G
authors.lastname: Sarah
authors.forename: Alphonse
authors.initials: A
authors.lastname: Omore
authors.forename: Tristan
authors.initials: T
authors.lastname: Durand-Gasselin
authors.forename: Fabienne
authors.initials: F
authors.lastname: Morcillo
mesh_terms: D029681:Arabidopsis Proteins / Q000235:genetics; D028023:Arecaceae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D001483:Base Sequence; D056625:Endosperm / Q000235:genetics / Q000378:metabolism; D005227:Fatty Acids / Q000032:analysis* / Q000096:biosynthesis; D005638:Fruit / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling / Q000379:methods; D018506:Gene Expression Regulation, Plant; D007850:Lauric Acids / Q000032:analysis / Q000378:metabolism; D008055:Lipids / Q000032:analysis; D008969:Molecular Sequence Data; D000073878:Palm Oil; D010802:Phylogeny; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010938:Plant Oils; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D012639:Seeds / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D013869:Thiolester Hydrolases / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D005227:Fatty Acids; D007850:Lauric Acids; D008055:Lipids; D010938:Plant Oils; D010940:Plant Proteins; D014157:Transcription Factors; D014280:Triglycerides; C495665:WRINKLED1 protein, Arabidopsis; C030358:lauric acid; D000073878:Palm Oil; D013869:Thiolester Hydrolases; C018748:oleoyl-(acyl-carrier-protein) hydrolase