Arabidopsis thaliana Transcriptome or Gene expression

Perturbation of the cellular redox state by stress conditions is sensed by redox-sensitive proteins so that the cell can physiologically respond to stressors; however, the mechanisms linking sensing to response remain poorly understood in plants. Here we report that the redox-sensitive protein bZIP68 is localized to the nucleus under normal conditions in Arabidopsis seedlings. Upon oxidative stress treatment, some bZIP68 molecules became cytosolic. This oxidative stress-induced nucleocytoplasmic shuttling is dependent on the redox-sensitive Cys320 residue of bZIP68. The bzip68 mutant seedlings displayed aberrant growth responses to exogenously applied soluble sugar (sucrose, glucose, or trehalose) and showed altered tolerance to oxidative stress in a sugar-dependent manner. Our study indicated that bZIP68 normally suppresses expression of stress tolerance genes to promote growth, whereas its inactivation enhances stress tolerance but suppresses growth. bZIP68 might balances stress tolerance with growth through the extent of its oxidative inactivation according to the environment.