title: High level accumulation of gamma linolenic acid (C18:3Δ6.9,12 cis) in transgenic safflower (Carthamus tinctorius) seeds.
abstract: Gamma linolenic acid (GLA; C18:3Δ6,9,12 cis), also known as γ-Linolenic acid, is an important essential fatty acid precursor for the synthesis of very long chain polyunsaturated fatty acids and important pathways involved in human health. GLA is synthesized from linoleic acid (LA; C18:2Δ9,12 cis) by endoplasmic reticulum associated Δ6-desaturase activity. Currently sources of GLA are limited to a small number of plant species with poor agronomic properties, and therefore an economical and abundant commercial source of GLA in an existing crop is highly desirable. To this end, the seed oil of a high LA cultivated species of safflower (Carthamus tinctorius) was modified by transformation with Δ6-desaturase from Saprolegnia diclina resulting in levels exceeding 70% (v/v) of GLA. Levels around 50% (v/v) of GLA in seed oil was achieved when Δ12-/Δ6-desaturases from Mortierella alpina was over-expressed in safflower cultivars with either a high LA or high oleic (OA; C18:1Δ9 cis) background. The differences in the overall levels of GLA suggest the accumulation of the novel fatty acid was not limited by a lack of incorporation into the triacylgylcerol backbone (>66% GLA achieved), or correlated with gene dosage (GLA levels independent of gene copy number), but rather reflected the differences in Δ6-desaturase activity from the two sources. To date, these represent the highest accumulation levels of a newly introduced fatty acid in a transgenic crop. Events from these studies have been propagated and recently received FDA approval for commercialization as Sonova™400.
authors.affiliation: SemBioSys Genetics Inc., 110, 2985-23 Ave NE, Calgary, AB, T1Y 7L3, Canada. nykiforukc@sembiosys.com
authors.forename: Cory L
authors.initials: CL
authors.lastname: Nykiforuk
authors.forename: Christine
authors.initials: C
authors.lastname: Shewmaker
authors.forename: Indra
authors.initials: I
authors.lastname: Harry
authors.forename: Olga P
authors.initials: OP
authors.lastname: Yurchenko
authors.forename: Mei
authors.initials: M
authors.lastname: Zhang
authors.forename: Catherine
authors.initials: C
authors.lastname: Reed
authors.forename: Gunamani S
authors.initials: GS
authors.lastname: Oinam
authors.forename: Steve
authors.initials: S
authors.lastname: Zaplachinski
authors.forename: Ana
authors.initials: A
authors.lastname: Fidantsef
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Boothe
authors.forename: Maurice M
authors.initials: MM
authors.lastname: Moloney
mesh_terms: D060054:Agrobacterium / Q000235:genetics / Q000378:metabolism; D031187:Carthamus tinctorius / Q000235:genetics / Q000378:metabolism*; D005591:Chemical Fractionation / Q000379:methods; D003470:Culture Media / Q000378:metabolism; D004789:Enzyme Activation; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D050602:Linoleoyl-CoA Desaturase / Q000235:genetics* / Q000378:metabolism; D019301:Oleic Acid / Q000378:metabolism; D010641:Phenotype; D010938:Plant Oils / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D044762:Saprolegnia / Q000201:enzymology* / Q000235:genetics; D012639:Seeds / Q000235:genetics / Q000378:metabolism*; D017965:gamma-Linolenic Acid / Q000096:biosynthesis*
chemical_list: D003470:Culture Media; D010938:Plant Oils; D010940:Plant Proteins; D011994:Recombinant Proteins; D019301:Oleic Acid; D017965:gamma-Linolenic Acid; D050602:Linoleoyl-CoA Desaturase