Changes in lipid peroxidation and flavonoid content in intact and transgenic potato plants ( Solanum tuberosum L.) after exposition to low temperature

Hypothermia leads to metabolic changes that can cause cell death. Thus, breeding varieties resistant to low temperatures is becoming increasingly important. For this purpose, genetic engineering approach is used to transfer genes of desaturases which catalyze the modification of single C-bonds in fatty acid acyl group to double bonds, resulting in an increase of cell membrane fluidity and changes in the antioxidant system. Polyphenols, the secondary plant metabolites, are considered the protective factors as low molecular weight antioxidants. Here we report the effect of short-term low temperature (-9 оС for 10 и 40 min) to lipid peroxidation and flavonoid content in leaves of in vitro cultivated plants of potato ( Solanum tuberosum L.) early ripening variety Skoroplodnii and its transgenic strains with middle and high expression of D12-acyl-lipid desaturase gene. For plant transgenesis, there was used construction of desA from Synechocystis sp. PCC 6803 conjugated to licBM3, encoding thermostable lichenase, a translational reporter, under control of strong constitutive promoter 35S RNA CaMV. It was found that after 10 min exposition to low temperature a peroxidation decreased in reference plants and remained unchanged in the transgenic plants. In case the plants were exposed to hypothermia for 40 min, the peroxidation was low in all variants, being minimal in transgenic plants with high D12-acyl-lipid desaturase gene expression. In all variants the flavonoid content in leaves increased when influenced by low temperature with the most pronounced effect observed in the reference variety.