Conclusions
Previous work demonstrated that PagR is necessary for full induction of the SPI-2 type-3 secretion system (Jiang et al., 2020). Our data show that PagR also regulates expression of the genes encoding the subunits of the TktC transketolase (i.e., tktD, tktE ), the third transketolase enzyme identified in S. Typhimurium (Shaw et al., 2018). Transketolases are essential for S. Typhimurium virulence (Shaw et al., 2018), and PagR appears to be a link between genetic regulation of the pathogenic machinery and a metabolic function essential for the pathogenic lifestyle of this bacterium. Moreover, the data presented here indicate that TktC has a function in the cell that differs from those of TktA and TktB. Future research into the identity of the co-efector of PagR and into the function of TktC, will illuminate the connections between central metabolism and the pathogenic machinery in S. Typhimurium.­­