Dihydrolipoamide Acetyltransferase AceF Influences the Type III Secretion System and Resistance to Oxidative Stresses through RsmY/Z in .

Carbon metabolism plays an important role in bacterial physiology and pathogenesis. The type III secretion system (T3SS) of is a virulence factor that contributes to acute infections. It has been demonstrated that bacterial metabolism affects the T3SS. Meanwhile, expression of T3SS genes is negatively regulated by the small RNAs RsmY and RsmZ. In this study, we studied the relationship between the dihydrolipoamide acetyltransferase gene and the T3SS. Our results reveal an upregulation of RsmY and RsmZ in the mutant, which represses the expression of the T3SS genes. Meanwhile, the mutant is more tolerant to hydrogen peroxide. We demonstrate that the expression levels of the catalase KatB and the alkyl hydroperoxide reductase AhpB are increased in the mutant. The simultaneous deletion of and in the mutant restored the expression levels of and , as well as bacterial susceptibility to hydrogen peroxide. Thus, we identify a novel role of AceF in the virulence and oxidative response of .