Double trouble: Bacillus depends on a functional Tat machinery to avoid severe oxidative stress and starvation upon entry into a NaCl-depleted environment

The widely conserved twin-arginine translocases (Tat) allow the transport of fully folded cofactor-containing proteins across biological membranes. In doing so, these serve different functions ranging from energy conversion to cell division. Gram-positive soil bacterium Bacillus subtilis, Tat machinery is essential for effective growth in media lacking iron or NaCl. It was previously shown that this phenomenon relates Tat-dependent export heme-containing peroxidase EfeB, which converts Fe2+ Fe3+ at expense hydrogen peroxide. However, reasons why majority tat mutant bacteria perish upon dilution NaCl-deprived medium and how, after several hours, a sub-population adapts condition unknown. Here we show that, absence NaCl, face two major problems, namely severe oxidative stress membrane starvation leading death. cells can overcome challenges if they are fed with arginine, implies arginine depletion cause death resumed synthesis permits their survival. Altogether, our findings system B. subtilis needed preclude sudden drops environmental Na+ concentration as caused by flooding rain.