Distinct Roles of Shewanella oneidensis Thioredoxin in Regulation of Cellular Responses to Hydrogen and Organic Peroxides

The Trx and Grx systems are deeply involved in bacterial responses to H2 O2 -induced oxidative stress. However, little is known about their roles in response to other ROS, such as organic peroxides (OPs). In this study, we usedS. oneidensis as a research model to investigate the interplay between Trx/Grx and OxyR/OhrR. We show that Trxs mediate the redox status of transcriptional OP-responding regulator OhrR. Although none of thetrx orgrx genes are directly controlled by OxyR or OhrR, expression oftrxA andtrxC is induced bytert -butyl hydroperoxide (t -BHP). We further show that thetrxA andtrxC genes respond to effects of glutathione (GSH) depletion rather than oxidation. These findings underscore the particular importance of Trx in the bacterial OP stress response.