ANNEXIN-LIKE PROTEIN FROM ARABIDOPSIS-THALIANA RESCUES DELTA-OXYR MUTANT OF ESCHERICHIA-COLI FROM H2O2 STRESS

Reactive oxygen species are common causes of cellular damages in all a erobic organisms. In Escherichia coli, the oxyR gene product is a posi tive regulator of the oxyR regulon that is induced in response to H2O2 stress. To identify genes involved in counteracting oxidative stress in plants, we transformed a Delta oxyR mutant of E. coli with an Arabi dopsis thaliana cDNA library and selected for clones that restored the ability of the Delta oxyR mutant to grow in the presence of H2O2. Usi ng this approach, we isolated a cDNA that has strong homology with the annexin super gene family, The complemented mutant showed higher cata lase activity. mRNA expression of the annexin gene in A. thaliana was higher in roots as compared with other organs and was also increased w hen the plants were exposed to H2O2 stress or salicylic acid, Based on the results presented in this study, we propose a novel physiological role for annexin in counteracting H2O2 stress.