title: Increased production of wax esters in transgenic tobacco plants by expression of a fatty acid reductase:wax synthase gene fusion.
abstract: Wax esters are hydrophobic lipids consisting of a fatty acid moiety linked to a fatty alcohol with an ester bond. Plant-derived wax esters are today of particular concern for their potential as cost-effective and sustainable sources of lubricants. However, this aspect is hampered by the fact that the level of wax esters in plants generally is too low to allow commercial exploitation. To investigate whether wax ester biosynthesis can be increased in plants using transgenic approaches, we have here exploited a fusion between two bacterial genes together encoding a single wax ester-forming enzyme, and targeted the resulting protein to chloroplasts in stably transformed tobacco (Nicotiana benthamiana) plants. Compared to wild-type controls, transgenic plants showed both in leaves and stems a significant increase in the total level of wax esters, being eight-fold at the whole plant level. The profiles of fatty acid methyl ester and fatty alcohol in wax esters were related, and C16 and C18 molecules constituted predominant forms. Strong transformants displayed certain developmental aberrations, such as stunted growth and chlorotic leaves and stems. These negative effects were associated with an accumulation of fatty alcohols, suggesting that an adequate balance between formation and esterification of fatty alcohols is crucial for a high wax ester production. The results show that wax ester engineering in transgenic plants is feasible, and suggest that higher yields may become achieved in the near future.
authors.affiliation: Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7080, 75007, Uppsala, Sweden.
authors.forename: Selcuk
authors.initials: S
authors.lastname: Aslan
authors.affiliation: Department of Plant Breeding, Swedish University of Agricultural Sciences (SLU), Alnarp, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Hofvander
authors.affiliation: Department of Food Science, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
authors.forename: Paresh
authors.initials: P
authors.lastname: Dutta
authors.affiliation: Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7080, 75007, Uppsala, Sweden.
authors.forename: Chuanxin
authors.initials: C
authors.lastname: Sun
authors.affiliation: Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7080, 75007, Uppsala, Sweden. Folke.Sitbon@slu.se.
authors.forename: Folke
authors.initials: F
authors.lastname: Sitbon
mesh_terms: D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D000445:Aldehyde Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D004952:Esters / Q000378:metabolism*; D050939:Gene Fusion / Q000502:physiology*; D010641:Phenotype; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D014026:Nicotiana / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D014885:Waxes / Q000378:metabolism*
chemical_list: D004952:Esters; D014885:Waxes; D000445:Aldehyde Oxidoreductases; C027902:fatty acid reductase; D000217:Acyltransferases; C079165:long-chain-alcohol O-fatty-acyltransferase
keywords: Fatty acyl reductase; Tobacco (Nicotiana benthamiana); Transgenic plants; Wax ester; Wax synthase