Specific features of oxidative stress in the chilled tobacco plants following transformation with the desC gene for acyl-lipid Δ9-desaturase from Synechococcus vulcanus

Tobacco plants (Nicotiana tabacurn L.) transformed with the desC gene for acyl-lipid Delta 9-desaturase from a thermophilic cyanobacterium Synechococcus vulcanus were cultivated on the agarized Murashige and Skoog medium at 22 degrees C and a 16-h photoperiod. Tobacco plants transformed with an empty binary vector pGA482 served as the control. The investigations showed that, in contrast to the control, transgenic plants maintained a higher activity of antioxidant enzymes during 2-h incubation at 2 degrees C; as a result, these plants resisted more efficiently the accumulation of reactive oxygen species and reduced the rate of the lipid peroxidation. The activity of antioxidant enzymes in the transformed plants is apparently related to the operation of the introduced desC gene for acyl-lipid Delta 9-desaturase because the enhanced activity of the latter increased the relative content of polyunsaturated FAs in membrane lipids and in this way promoted the liquid state of membranes during the chilling period. These changes helped preserve the cellular homeostasis and thereby maintain the steady synthesis of antioxidant enzymes at hypothermic conditions; as a result, cold resistance of transformed tobacco plants increased.