Expression pattern of two dehydroascorbate reductase genes from tomato (Solanum lycopersicum L.) in response to stress

Dehydroascorbate reductase (DHAR) plays an important role in the ascorbate-glutathione cycle in plants by controlling the homeostasis of reactive oxygen species. Expression profiles of two DHAR genes (SlDHAR1 and SlDHAR2) in tomato leaves were analyzed in response to abiotic and oxidative stresses as well as their expression in various organs were investigated under normal growth conditions. Multiple copies of SlDHAR homologues exist in the tomato genome. SlDHAR1 expression was dominant in stems and flowers but moderate in leaves; however, SlDHAR2 induction was strong in stems, leaves, and flowers, and young leaves showed the highest expression of SlDHAR2. Both genes were transcribed after treatment with salt, dehydration, and methyl viologen. Prolonged stress reduced SlDHAR genes expression. The level of hydrogen peroxide increased, and DHAR activity was altered by stress treatment. Results indicate that SlDHAR genes could play a role in multiple stress responses.