Inactivation of () induces the SOS response and MGEs mobilization and silences the general stress response and virulence program in .

Bacteria have evolved numerous regulatory pathways to survive in changing environments. The SOS response is an inducible DNA damage repair system that plays an indispensable role in bacterial adaptation and pathogenesis. Here we report a discovery of the previously uncharacterized protein Lmo0946 as an SOS response interfering factor (Sif) in the human pathogen Functional genetic studies demonstrated that is indispensable for normal growth of in stress-free as well as multi-stress conditions, and contributes to susceptibility to β-lactam antibiotics, biofilm formation and virulence.