Oil-from-flax project shows new life for oilseeds

Researchers at University of Hamburg in Germany have provided a glimpse of the future of oilseed crops, by modifying the oil-synthesis pathways in flax to synthesise low levels of health-boosting omega-3 and omega-6 fatty acids in its seeds.

Flax (Linum marginale) has already had three incarnations as a crop: the tough fibres in the crop are used to weave linen, and it provided linseed oil as a pain-thinner in the pre-acrylic era.

In the early 1980s, Dr Allan Green's research team at CSIRO Plant Industry used mutation breeding to modify the inedible linseed oil (linolenic acid) into edible, polyunsaturated linoleic acid. The new crop, Linola, is now grown widely in Canada.

The online forum www.whybiotech.com reported this week that Dr Ernst Heinz's team has succeeded in introducing three genes, from marine algae and moss, into flax.

Green said the three genes code for three plant enzymes: two desaturases and a for three plant enzymes into flax: two desaturases and an elongase to create a flax whose seeds contain about 5 per cent of the very long chain fatty acid eicosapentanoic acid (EPA).

Another research team recently achieved expression of omega-3 fatty acids in the leaves of Arabidopsis, but Green said the German team was the first to demonstrate expression in seeds.

Green, whose Plant Industry research group has been experimenting with a similar approach in the model plant Arabidopsis, described the achievement as an "interim" result -- the low level of EPA expression is not commercially useful. Several more genes would required to achieve expression of docosahexanoic acid (DHA) -- "a much harder task", according to Green, but one that is even more desirable from a human-health perspective.

Research by CSIRO and other research agencies has confirmed the crucial role of omega-3 fatty acids -- DHA in particular -- in the health development and functioning of the brain and visual system.

Research has implicated DHA deficiency, due to excessive consumption of polyunsaturated and saturated fats in fast foods, in childhood behavioural disorders, including attention-deficit hyperactivity disorder.

Currently, marine fish are the food industry's chief source of omega-3 fatty acids in the human diet. Species like Atlantic salmon, mackerel, tuna and sardines accumulate omega-3 fatty acids through their diet, but its ultimate source is marine algae. Marine fish are not a sustainable resource of the healthy oil, so plant biotechnologists are trying to install the omega-3 synthesis pathway in oilseed crops.

Green's CSIRO group is continuing to experiment in Arabidopsis. It has yet to select an oilseed crop for modification, but Green said the technology, once proven, could be deployed in any oilseed crop.

For Australia, the possibilities include flax (linseed), canola, or cottonseed -- the latter is attractive because Australians already eat cottonseed oil from genetically modified cotton varieties.