title: SdiA improves the acid tolerance of E. coli by regulating GadW and GadY expression
design: To assess the influence of SdiA on acid tolerance of E. coli, we first constructed sdiA gene-deficient strain in SM10(sdiA), as well as sdiA-overexpression strain in sdiA mutation (sdiA/SdiA). Then a series of growth assaise under different acid stress (24 h of incubation in LBG medium acidified to pH 3-7 by HCl) were performed. Next, we explored the molecular mechanisms responsible for the function of SdiA that were observed above. The transcriptomes of SM10pir, SM10pirsdiA, SM10pirsdiA-SdiA were determined and we mainly focused on AR2 system genes. The results showed that the transcription of gadA, gadB, gadC, gadE and gadX was hardly changed in sdiA-knockouted strain, while overexpression of SdiA enhanced gadA, gadB and gadC expression. This is consistent with the observation that many genes of E. coli that respond to plasmid-based expression of SdiA are largely more different than those that respond to chromosomal SdiA. Noteworthy, the expression of GadW and GadY was changed in both sdiA gene-deficient and its compensatory strains, with the down-regulation in SM10pirsdiA, and up-regulation upon SdiA.
identifiers.namespace: SUB7310485
identifiers.id: E.coli-3