Expression of a cyanobacterial Delta(6)-desaturase gene results in gamma-linolenic acid production in transgenic plants

Gamma-linolenic acid (GLA), a nutritionally important fatty acid in human and animal diets, is not produced in oil seed crops. Many oil seed plants, however, produce significant quantities of linoleic acid, a fatty acid that could be converted to GLA by the enzyme Delta(6)-desaturase if it were present. As a first step to producing GLA in oil seed crops, we have cloned a cyanobacterial Delta(6)-desaturase gene. Expression of this gene in transgenic tobacco resulted in GLA accumulation. Octadecatetraenoic acid, a highly unsaturated, industrially important fatty acid, was also found in transgenic tobacco plants expressing the cyanobacterial Delta(6)-desaturase. This is the first example of engineering the production of 'novel' polyunsaturated fatty acids in transgenic plants.