title: Contained metabolic engineering in tomatoes by expression of carotenoid biosynthesis genes from the plastid genome.
abstract: Applications of chloroplast engineering in agriculture and biotechnology will depend critically on success in extending the crop range of chloroplast transformation, and on the feasibility of expressing transgenes in edible organs (such as tubers and fruits), which often are not green and thus are much less active in chloroplast gene expression. We have improved a recently developed chloroplast-transformation system for tomato plants and applied it to engineering one of the central metabolic pathways in fruits: carotenoid biosynthesis. We report that plastid expression of a bacterial lycopene beta-cyclase gene results in herbicide resistance and triggers conversion of lycopene, the main storage carotenoid of tomatoes, to beta-carotene, resulting in fourfold enhanced pro-vitamin A content of the fruits. Our results demonstrate the feasibility of engineering nutritionally important biochemical pathways in non-green plastids by transformation of the chloroplast genome.
authors.affiliation: Max-Planck-Institut für Molekulare Pflanzenphysiologie (MPI-MP), Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Wurbs
authors.forename: Stephanie
authors.initials: S
authors.lastname: Ruf
authors.forename: Ralph
authors.initials: R
authors.lastname: Bock
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002338:Carotenoids / Q000096:biosynthesis*; D002736:Chloroplasts / Q000235:genetics*; D002851:Chromatography, High Pressure Liquid; D018742:DNA, Chloroplast / Q000235:genetics; D004885:Erwinia / Q000201:enzymology / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D005818:Genetic Engineering / Q000379:methods; D005822:Genetic Vectors / Q000235:genetics; D053209:Herbicide Resistance / Q000235:genetics; D019753:Intramolecular Lyases / Q000235:genetics* / Q000378:metabolism; D018551:Solanum lycopersicum / Q000235:genetics* / Q000378:metabolism; D010800:Phycomyces / Q000201:enzymology / Q000235:genetics; D030821:Plants, Genetically Modified; D014170:Transformation, Genetic; D019076:Transgenes / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D018742:DNA, Chloroplast; D005656:Fungal Proteins; D002338:Carotenoids; D019753:Intramolecular Lyases; C070925:lycopene cyclase-isomerase