Overexpression of the acyl-lipid Δ12-desaturase gene protects potato plants from low temperature damage

The responses of plant leaves to chilling were studied in potato (Solanum tuberosum L., cv. Desnitsa) and in its transformants with the native desA gene that encodes the acyl-lipid Δ12-desaturase from the cyanobacterium Synechocystis sp. PCC 6803 and with the hybrid desA gene fused to the reporter gene of thermostable lichenase (licBM3) from Clostridium thermocellum. Cold stress caused a rapid and significant increase in superoxide production and lipid peroxidation (the content of conjugated dienes and malonic dialdehyde) in wild-type plants. By contrast no significant increase was detected in transformed plants under cold stress conditions. This can be attributed to the fact that the overexpression of the acyl-lipid Δ12-desaturase in transformed potato plants promotes fatty acid polyunsaturation and presumably averts the accelerated generation of the superoxide anion, thus suppressing lipid peroxidation under low-temperature stress