High level production of adrenic acid in Physcomitrella patens using the algae Pavlova sp. Δ5-elongase gene

Adrenic acid (ADA), an ω-6 polyunsaturated fatty acid (PUFA), has attracted much interest due to its pharmaceutical potential. Exploiting the wealth of information currently available on in planta oil biosynthesis, and coupling this information with the tool of genetic engineering, it is now feasible to deliberately alter fatty acid biosynthetic pathways to generate unique oils in commodity crops. In this study, a Δ5-elongase gene from the algae Pavlova sp. related to the biosynthesis of C22 PUFAs was targeted to enable production of ADA in the moss Physcomitrella patens. Heterologous expression of this gene was under the control of a tandemly duplicate 35S promoter. It was established that ADA (0.42 mg/l) was synthesized in P. patens from endogenous arachidonic acid (ARA) via the expressed Pavlova sp. Δ5-elongase in the moss. In an attempt to maximize ADA production, medium optimization was effected by the response surface methodology (RSM), resulting in a significant elevation of ADA (4.51 mg/l) production under optimum conditions. To the best of our knowledge, this is the first study describing the expression of a PUFA synthesizing enzyme in non-seed lower plant without supplying the exogenous fatty acid.