Production of eicosapentaenoic acid (EPA, 20:5n-3) in transgenic peanut (Arachis hypogaea L.) through the alternative Δ8-desaturase pathway.

An important alternative source of fish oil is its production by plants through metabolic engineering. To produce eicosapentaenoic acid (EPA, 20:5n-3) in peanut through the alternative Δ8-pathway, a plant expression vector containing five heterologous genes driven by the constitutive 35S promoter respectively, namely, ∆9-elongase (Isochrysis galbana), ∆8-desaturase (Euglena gracilis), ∆5-desaturase (Mortierella alpina), ∆15-desaturase (Arabidopsis thaliana) and ∆17-desaturase (Phytophthora infestans) were transferred into peanut through Agrobacterium-mediated transformation method. The gas chromatography results indicated that the average content of EPA in the leaves of the transgenic lines was 0.68%, and the highest accumulation of EPA in an individual line reached 0.84%. This finding indicates that it is feasible to synthesize EPA in peanut through metabolic engineering and lays the foundations for the production of very-long-chain polyunsaturated fatty acids (VLCPUFAs) in peanut seeds.