Variation of antioxidant enzyme gene expression during cold storage of aubergine

Reactive oxygen species (ROS) are dangerous molecules because they can cause damage to proteins, lipids and nucleic acids. ROS production in plants increases at low temperatures; particularly sub-tropical species are sensitive to ROS when they are exposed to temperatures below 10 degrees C. To prevent damage from ROS and to scavenge them, plants developed an enzymatic and a non-enzymatic antioxidant system. The enzymatic antioxidant system was studied in this work during the post-harvest cold storage of aubergine using the real time PCR technique in order to monitor changes in the transcript level of genes encoding for ROS scavenging enzymes. Changes in Mn Superoxide-dismutase, Catalase, Glutathione reductase, Ascorbate peroxidase gene expression were analyzed during storage at 0 degrees C and at 10 degrees C up to 10 days. Catalase gene expression is stimulated during storage at 10 degrees C and inhibited at 0 degrees C. Equally, Glutathione reductase gene expression is upregulated in this milder refrigeration condition. On the contrary Mn-superoxide dismutase and Ascorbate peroxidase transcript levels decrease with respect to the initial amount for both temperatures. This suggests that oxidative stress can cause damage during cold storage of aubergine. The expression of ROS scavenging enzymes is positively regulated during the 10 degrees C cold storage contrary to the 0 degrees C cold storage, indicating the presence of oxidative stress and a tissue reaction.