Arsenite Mediates Selenite Resistance and Reduction in Enterobacter sp. Z1, Thereby Enhancing Bacterial Survival in Selenium Environments

Arsenic (As) is widely present in the environment, and virtually all bacteria possess a conserved ars operon to resist As toxicity. High selenium (Se) concentrations tend to be cytotoxic. Se has an uneven regional distribution and is added to mitigate As contamination in Se-deficient areas. However, the bacterial response to exogenous Se remains poorly understood. Herein, we found that As­(III) presence was crucial for Enterobacter sp. Z1 to develop resistance against Se­(IV). Se­(IV) reduction served as a detoxification mechanism in bacteria, and our results demonstrated an increase in the production of Se nanoparticles (SeNPs) in the presence of As­(III). Tandem mass tag proteomics analysis revealed that the induction of As­(III) activated the inositol phosphate, butanoyl-CoA/dodecanoyl-CoA, TCA cycle, and tyrosine metabolism pathways, thereby enhancing bacterial metabolism to resist Se­(IV). Additionally, arsHRBC, sdr-mdr, purHD, and grxA were activated to participate in the reduction of Se­(IV) into SeNPs. Our findings provide innovative perspectives for exploring As-induced Se biotransformation in prokaryotes.