title: Expression of a borage desaturase cDNA containing an N-terminal cytochrome b5 domain results in the accumulation of high levels of delta6-desaturated fatty acids in transgenic tobacco.
abstract: gamma-Linolenic acid (GLA; C18:3 delta(6,9,12)) is a component of the seed oils of evening primrose (Oenothera spp.), borage (Borago officinalis L.), and some other plants. It is widely used as a dietary supplement and for treatment of various medical conditions. GLA is synthesized by a delta6-fatty acid desaturase using linoleic acid (C18:2 delta(9,12)) as a substrate. To enable the production of GLA in conventional oilseeds, we have isolated a cDNA encoding the delta6-fatty acid desaturase from developing seeds of borage and confirmed its function by expression in transgenic tobacco plants. Analysis of leaf lipids from a transformed plant demonstrated the accumulation of GLA and octadecatetraenoic acid (C18:4 delta(6,9,12,15)) to levels of 13.2% and 9.6% of the total fatty acids, respectively. The borage delta6-fatty acid desaturase differs from other desaturase enzymes, characterized from higher plants previously, by the presence of an N-terminal domain related to cytochrome b5.
authors.affiliation: Institute of Arable Crops Research-Long Ashton Research Station, University of Bristol, United Kingdom.
authors.forename: O
authors.initials: O
authors.lastname: Sayanova
authors.forename: M A
authors.initials: MA
authors.lastname: Smith
authors.forename: P
authors.initials: P
authors.lastname: Lapinskas
authors.forename: A K
authors.initials: AK
authors.lastname: Stobart
authors.forename: G
authors.initials: G
authors.lastname: Dobson
authors.forename: W W
authors.initials: WW
authors.lastname: Christie
authors.forename: P R
authors.initials: PR
authors.lastname: Shewry
authors.forename: J A
authors.initials: JA
authors.lastname: Napier
mesh_terms: D000595:Amino Acid Sequence; D015786:Cytochromes b5 / Q000235:genetics*; D018076:DNA, Complementary / Q000235:genetics* / Q000302:isolation & purification; D044943:Fatty Acid Desaturases / Q000235:genetics*; D015870:Gene Expression; D050602:Linoleoyl-CoA Desaturase; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified / Q000235:genetics*; D010947:Plants, Toxic; D016415:Sequence Alignment; D014026:Nicotiana / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D015786:Cytochromes b5; D044943:Fatty Acid Desaturases; D050602:Linoleoyl-CoA Desaturase