The effect of potato plant transformation with the gene encoding Δ12-acyl-lipid desaturase on the CO2 exchange and activities of antioxidant enzymes under hypothermia

The effects of potato (Solanum tuberosum L., cv. Desnitsa) plant transformation with the desA gene encoding Delta 12-acyl-lipid desaturase from Synechocystis sp. PCC 6803 on the regulation of free-radical processes in relation to plant tolerance to hypothermia are considered. It was shown that the content of polyunsaturated fatty acids (PUFA) in transformed plants was higher than in wild-type ones. In particular, the content of linoleic acid in transformants was higher by 35% and the content of linolenic acid was by 41% higher than in untransformed plants. In addition, transformation induced an increase in the absolute content of C-16-PUFA and on the whole resulted in a marked accumulation of membrane lipids. As judged from the values of the damage index and the ratio of photosynthesis to respiration in wild-type and transformed plants under cold treatment, these changes in lipid metabolism favored the protection of coupling membranes, thus preventing plants against free-radical oxidation under low-temperature stress. As a result, the intensity of oxidative stress in transformed plants was much lower than in wild-type ones, whereas antioxidant enzymes (superoxide dismutase, catalase, peroxidase) were not substantially activated under hypothermia.