title: Metabolic engineering of astaxanthin biosynthesis in maize endosperm and characterization of a prototype high oil hybrid.
abstract: Maize was genetically engineered for the biosynthesis of the high value carotenoid astaxanthin in the kernel endosperm. Introduction of a β-carotene hydroxylase and a β-carotene ketolase into a white maize genetic background extended the carotenoid pathway to astaxanthin. Simultaneously, phytoene synthase, the controlling enzyme of carotenogenesis, was over-expressed for enhanced carotenoid production and lycopene ε-cyclase was knocked-down to direct more precursors into the β-branch of the extended ketocarotenoid pathway which ends with astaxanthin. This astaxanthin-accumulating transgenic line was crossed into a high oil- maize genotype in order to increase the storage capacity for lipophilic astaxanthin. The high oil astaxanthin hybrid was compared to its astaxanthin producing parent. We report an in depth metabolomic and proteomic analysis which revealed major up- or down- regulation of genes involved in primary metabolism. Specifically, amino acid biosynthesis and the citric acid cycle which compete with the synthesis or utilization of pyruvate and glyceraldehyde 3-phosphate, the precursors for carotenogenesis, were down-regulated. Nevertheless, principal component analysis demonstrated that this compositional change is within the range of the two wild type parents used to generate the high oil producing astaxanthin hybrid.
authors.affiliation: Department of Plant Production and Forestry Science, University of Lleida-Agrotecnio Center, Lleida, Spain.
authors.forename: Gemma
authors.initials: G
authors.lastname: Farré
authors.affiliation: School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, UK.
authors.forename: Laura
authors.initials: L
authors.lastname: Perez-Fons
authors.affiliation: Unité de Biochimie et Physiologie Moléculaire des Plantes, INRA Montpellier, Montpellier, France.|Institut de Génétique et de Biologie Moléculaire et Cellulairem, UMR 7104, Illkirch, France.
authors.forename: Mathilde
authors.initials: M
authors.lastname: Decourcelle
authors.affiliation: Biosynthesis Group, Institute of Molecular Biosciences, Goethe University Frankfurt/M, Max von Laue Str. 9, 60438, Frankfurt, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Breitenbach
authors.affiliation: Unité de Biochimie et Physiologie Moléculaire des Plantes, INRA Montpellier, Montpellier, France.
authors.forename: Sonia
authors.initials: S
authors.lastname: Hem
authors.affiliation: Department of Plant Production and Forestry Science, University of Lleida-Agrotecnio Center, Lleida, Spain.
authors.forename: Changfu
authors.initials: C
authors.lastname: Zhu
authors.affiliation: Department of Plant Production and Forestry Science, University of Lleida-Agrotecnio Center, Lleida, Spain.
authors.forename: Teresa
authors.initials: T
authors.lastname: Capell
authors.affiliation: Department of Plant Production and Forestry Science, University of Lleida-Agrotecnio Center, Lleida, Spain.|Catalan Institute for Research and Advanced Studies (ICREA), Barcelona, Spain.
authors.forename: Paul
authors.initials: P
authors.lastname: Christou
authors.affiliation: School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, UK.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Fraser
authors.affiliation: Biosynthesis Group, Institute of Molecular Biosciences, Goethe University Frankfurt/M, Max von Laue Str. 9, 60438, Frankfurt, Germany. sandmann@bio.uni-frankfurt.de.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Sandmann
mesh_terms: D002338:Carotenoids / Q000235:genetics / Q000378:metabolism; D056625:Endosperm / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D060847:Metabolic Engineering / Q000379:methods*; D055442:Metabolome; D030821:Plants, Genetically Modified; D020543:Proteome / Q000378:metabolism; D024341:Xanthophylls / Q000096:biosynthesis / Q000235:genetics; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism*
chemical_list: D020543:Proteome; D024341:Xanthophylls; D002338:Carotenoids; C005948:astaxanthine
keywords: Astaxanthin; GM maize; Genetically engineered carotenoid biosynthesis; Metabolomics; Transcriptomics