We have focused on the study of redox signaling systems and the response of plants to oxidative stress using two model systems: Arabidopsis and cereals. In Arabidopsis our main objective was to establish the function of NTRC, a peculiar NTR with a joint Trx domain at the C-terminus with chloroplast localization, for which we have proposed a reaction mechanism. We have also established the central function of NTRC to maintain the redox homeostasis of the chloroplast, involved in the regulation of processes such as starch synthesis. Finally, we have shown for the first time the existence of overoxidation sensitive 2-Cys Prx in prokaryotic organisms, such as the cyanobacterium Anabaena. In a second objective that we have addressed, mechanisms of detoxification in cereal seed cells, we have shown that the antioxidant system formed by NTR, Trx and 1-Cys Prx is accumulated in the nucleus of seed cells, thus suggesting its function in redox control of gene expression.