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.
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.
Sayanova
O
O
Institute of Arable Crops Research-Long Ashton Research Station, University of Bristol, United Kingdom.
Smith
M A
MA
Lapinskas
P
P
Stobart
A K
AK
Dobson
G
G
Christie
W W
WW
Shewry
P R
PR
Napier
J A
JA
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*
D018076:DNA, Complementary; D015786:Cytochromes b5; D044943:Fatty Acid Desaturases; D050602:Linoleoyl-CoA Desaturase