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.