Lipid fatty acid composition of potato plants transformed with the Delta 12-desaturase gene from cyanobacterium

Potato (Solanum tuberosum L.) plants were transformed with the desA gene encoding Delta 12 acyl-lipid desaturase in the cyanobacterium Synechocystis sp. PCC 6803. To evaluate the efficiency of this gene expression in the plant, its sequence was translationally fused with the sequence of the reporter gene encoding thermostable lichenase. A comparison of native and hybrid gene expression showed that lichenase retained its activity and thermostability within the hybrid protein, whereas desaturase retained its capability of inserting the double bond in fatty acid (FA) chains and, thus, to modify their composition in membrane lipids. In most transformed plants, shoots contained higher amounts of polyunsaturated FAs, linoleic and linolenic (by 39-73 and 12-41%, respectively). The total absolute content of unsaturated FAs was also higher in transformants by 20-42% as compared to wild-type plants. When transformed plants were severely cooled (to -7 degree C), the rate of their membrane lipid peroxidation was not enhanced, whereas in wild-type plants, it increased substantially (by 25%) under such conditions. These results could indicate a higher tolerance of transformed plants to low temperatures and the oxidative stress induced by hypothermia.