May play a role in resistance to osmotic downshock. Expression is sigma B-dependent. Induced by high salt concentrations. Cells lacking this gene grow normally in minimal medium or in high-osmolarity environments, and exhibit the same survival capacity as the wild-type strain upon a drastic osmotic downshift. They sporulate and germinate normally. Combination with an MscL mutation enhances the osmosensitivity of MscL mutants subsequent to a hypo-osmotic shock. Belongs to the MscS (TC 1.A.23) family.