Activities of Hydrogen Peroxide-Scavenging Enzymes during Low-Temperature Hardening of Potato Plants Transformed by the desA Gene of Δ12-Acyl-Lipid Desaturase

Changes in Fatty Acid Composition and Lipid Content Occurring in Potato Leaves during Cold Hardening: the Role of ∆12-Acyl-Lipid Desaturase

“…As for the activities of ∆12and Δ15(ω3)-desaturases calculated for the hardening period, they hardly changed, though 15:0 14 ± 1 0.4 0 ± 0 0 ± 0 0 ± 0 0 ± 0 0 ± 0 0 ± 0 some authors described an increase in the level of expression of the FAD6 gene encoding ∆12-desaturase localized in chloroplasts and involved in the formation of linoleic (С 18:2 ) acid during the first hours of cold hardening of potato [20]. Thus, according to the results of our study, cell membranes of potato leaves during hardening are enriched with FA (including PUFA), which agrees with the data about an increase in the resistance of these plants to frost (Table 1) and oxidative stress [6]. Lavrova et al [16] showed that the long-term hardening of potato at low temperatures caused an increase in the content of unsaturated FA in lipids at the expense of diene and triene FA, while short-term cold exposure resulted in an increase only in the content of triene FA and, therefore, the activity of ω3-desaturases.…”

“…Thus, based on the obtained data, we can conclude that the total FA of membrane lipids in leaves of control potato plants during a low-temperature hardening process increases by ~25% mainly due to the PUFA accumulation. This process is probably caused by the activation of lipid metabolism (including desaturase enzymes) by a hardening temperature, which results in a more stable functioning of cell membrane structures and the prevention of a partial electron drop to oxygen with ROS formation [5,6]. Note that membrane rich in PUFAs are now considered as supramolecular antioxidants; their oxidation may represent a mechanism of protection of other important macromolecules from ROS [28].…”

“…The growing conditions included 22°С, 16-h photoperiod, and illumination equal to 100 μmol quanta/(m 2 s). The hardening was carried out at 5°С for six days in accordance with our previous study [6].…”

“…Based on this hypothesis, we first studied a long-term effect of low hardening temperatures on the oxidative stress (OS) processes in potato, a typical representative of chilling-tolerant plants. The obtained data showed that, unlike chilling-sensitive plants, potato plants subjected to prolonged hypothermia without ice formation do not show any significant accumulation of ROS and activation of LP processes [5,6]. Therefore, cell membranes of potato plants (including chloroplasts and mitochondria membranes representing the main ROS producers in the case of an impaired functional activity) are rather OS-resistant.…”