Healthy omega-3 enhacement in Echium acanthocarpum transformed hairy roots by overexpression of a 6-desaturase gene from Primula vialli

Omega-3 long change polyunsaturated fatty acids in higher plants are limited with just a few plant genus showing the accumulation of stearidonic acid (SDA) being also the longest and more unsaturated omega-3 fatty acid present. Echium acanthocarpum has been proven to be an efficient and attractive producer of SDA. Improved production of this fatty acid was attained by overexpression of a Δ6-desaturase gene from Primula vialii in transgenic E. acanthocarpum hairy roots. In this transgenic line, a drastic reduction of the substrates LA (linoleic acid) and ALA (α-linolenic acid)(40 and 30%, respectively) was parallel to the dramatic increase in GLA (γ-linolenic acid) and SDA in the total fatty acids extracted. Especially, SDA reached a percentage of 4.7% of total fatty acids, demonstrating the successful manipulation of this biosynthetic pathway in E. acanthocarpum hairy roots by overexpression of this gene. The temperature per se, was also a highly influential factor governing the fatty acid profiles in this novel transgenic hairy root culture. In terms of absolute values, the data were even more evident, due to the significant increase in total lipid extracted from the transgenic hairy root. The amount of SDA and GLA was increased 7.5 and 3 fold, respectively, compared to the control. In this transgenic culture, decreasing the culture temperature influenced directly the increments of polyunsaturated fatty acids, but did not affect lipid classes except when this factor interacted with the overexpression of the P. vialii Δ6-desaturase gene. The activation of the transgene did modify significantly the phospholipids, phosphatidylglycerol and phosphatidylcholine, whose percentages were significantly higher in these cultures compared to the control.