SdiA improves the acid tolerance of E. coli by regulating GadW and GadY expression
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.
SUB7310485
E.coli-3