Hydrogen sulfide (H2S) is a gasotransmitter produced primarily by gut microbiota and has emerged as an important signaling molecule in gut bacteria, as beneficial levels can protect pathogenic bacteria from oxidative stress that arises from inflammatory responses or antibiotics, and microbiota-derived H2S can be toxic for invading bacterial pathogens in the gut. Reactive sulfur species (RSS) containing sulfane sulfur derived from H2S, mediate these beneficial and toxic effects by modifying reactive cysteines through a post-translational modification called persulfidation. Therefore, maintaining RSS homeostasis is essential to leverage their benefits while preventing toxicity. Bacteria achieve this homeostasis by expressing persulfide-sensing transcriptional regulators whose regulon encodes for sulfur detoxification genes.
Here we will discuss recent advances in the mechanism of RSS sensing in different pathogenic and non-pathogenic bacteria, as well as multiomic approaches to study the response to RSS accumulation and RSS-derived post-translational modifications in bacteria.