The Gene Hunter: exploring fungal genes for the production of omega-3 fatty acids

Building on the success of the Bioactive Oils Program, one of Phytolaʼs core objectives is to develop oilseeds containing very long chain polyunsaturated fatty acids (VLCPUFAs) for applications in aquaculture.

For more than a decade, Dr. Xiao Qiu (University of Saskatchewan) has been a major player in the hunt for novel genes for producing VLCPUFAs in plants. In 2005, his group was the first to report the successful production of docosahexaenoic acid (DHA) in an oilseed crop. Since then, much of his work has focused on other nutritionally important fatty acids in the same pathway, and on developing strategies to increase the selective accumulation of omega-3 PUFAs, which are vitally important for the aquaculture industry and for human health.

Recently, Qiuʼs group has isolated an omega-3 specific desaturase gene from a fungus called Claviceps purpurea. The enzyme encoded by this desaturase gene is capable of converting omega-6 fatty acids to omega-3 fatty acids, an activity not normally present in animals or plants. This enzyme not only increases the availability of omega-3 fatty acid precursors, but can also convert omega-6 by-products into their more desirable omega-3 counterparts.

Currently, his group is working on newly identified desaturase and elongase enzymes from a variety of other fungal sources.

“Selection of PUFA genes from diverse sources, especially from non-plant sources, can make a positive contribution to transgenic production of VLCPUFAs”, explains Qiu. “Because these genes have less similarity to their plant homologues, they might be subject to less stringent regulatory control by the host plant.”

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