Evidence for a role of Ethylene-Insensitive 2 gene in the regulation of the oxidative stress response in Arabidopsis

The A rabidopsis Ethylene-Insensitive 2 (EIN2) gene has been shown to be involved in mediating the oxidative stress response: however, little is known about the underlying mechanisms involved. In this study, we found that the ethylene-insensilive mutant ein2-1 showed enhanced tolerance to oxidative stresses caused by both paraquat (PQ) and hydrogen peroxide as well as alleviated oxidative damage. Moreover, higher transcript levels of a choroplast Cu/Zn superoxide dismutase gene CSD2 and a catalase gene CAT3 and, consequently, higher activities of superoxide dismutase (SOD) and catalase (CAT), were detected in ein2-1 plants than in wild-type plants in the absence or presence of PQ. These results suggest that the ein2-1mutation results in constitutive activation of CSD2 and CAT3 genes and increases in the activities of SOD and CAT and, consequently, enhanced oxidative stress tolerance.