title: Improved stearate phenotype in transgenic canola expressing a modified acyl-acyl carrier protein thioesterase.
abstract: The engineering of crops for selected fatty acid production is one of the major goals of plant biotechnology. The Garm FatA1, an acyl-acyl carrier protein (ACP) thioesterase isolated from Garcinia mangostana, generates an elevated stearate (18:0) phenotype in transgenic Brassica plants. By site-directed mutagenesis, we generated seven mutants that showed up to a 13-fold increase in specific enzyme activity toward 18:0-ACP in vitro. The seed-specific expression of mutant S111A/V193A in Brassica plants results in transgenic plants that accumulate 55-68% more stearate than plants expressing the wild-type enzyme. Our results demonstrate that a thioesterase can be engineered to increase specific activity and that its improved function demonstrated in vitro is retained in vivo.
authors.affiliation: Calgene, LLC, Davis, CA 95616, USA.
authors.forename: M T
authors.initials: MT
authors.lastname: Facciotti
authors.forename: P B
authors.initials: PB
authors.lastname: Bertain
authors.forename: L
authors.initials: L
authors.lastname: Yuan
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001937:Brassica / Q000235:genetics* / Q000378:metabolism; D017931:DNA Primers; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D030821:Plants, Genetically Modified / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013229:Stearic Acids / Q000378:metabolism*; D013869:Thiolester Hydrolases / Q000235:genetics*
chemical_list: D017931:DNA Primers; D013229:Stearic Acids; C031183:stearic acid; D013869:Thiolester Hydrolases; C018748:oleoyl-(acyl-carrier-protein) hydrolase