Table 1 Bacterial strains used in this study.

SL1344

S. Typhimurium wild type strain, hisG

¹⁴

E. coli MC1061λpir

hsdR mcrB araD139 ∆(araABC-leu)7679 ∆lacX74 gal1 galK rpsL thi λpir

¹⁵

E. coli MFDpir

MG1655 RP4-2-TC::[∆Mu1::aac(3)IV-∆aphA-∆nic35-∆Mu2::zeo] ∆dapA::(erm-pir) ∆recA

¹⁶

E. coli DH10B

F^- araDJ39 ∆(ara, leu)7697 ∆lacX74 galU galK rpsL deoR ɸ80dlacZ∆M15 endAI nupG recAl mcrA ∆(mrr hsdRMS mcrBC)

¹⁷

∆invA

invA single deletion mutant in SL1344 genetic background; non-functional T3SS1 apparatus

¹⁸

∆ssaR

ssaR single deletion mutant in SL1344 genetic background; non-functional T3SS2 apparatus

¹⁹

T3SS2⁺

chromosomal duplication of ssrB in SL1344 resulting in increased expression of SPI-2 and its associated effectors

This study

T3SS2⁺ ∆sifA

sifA single deletion mutant in the ssrB overexpressing mutant background

This study

T3SS2⁺ ∆sifA-pSifA-2HA

sifA single deletion mutant in the ssrB overexpressing mutant background complemented with pSifA-2HA

This study

T3SS2⁺ ∆sopD2

sopD2 single deletion mutant in the ssrB overexpressing mutant background

This study

T3SS2⁺ ∆sopD2-pSopD2-2HA

sopD2 single deletion mutant in the ssrB overexpressing mutant background complemented with pSopD2-2HA

This study

T3SS2⁺ ∆pipB2

pipB2 single deletion mutant in the ssrB overexpressing mutant background

This study

T3SS2⁺ ∆pipB2-pPipB2-2HA

pipB2 single deletion mutant in the ssrB overexpressing mutant background complemented with pPipB2-2HA

This study

T3SS2⁺ ∆steA

steA single deletion mutant in the ssrB overexpressing mutant background

This study

T3SS2⁺ ∆steA-pSteA-2HA

steA single deletion mutant in the ssrB overexpressing mutant background complemented with pSteA-2HA

This study

T3SS2⁺ ∆sseJ

sseJ single deletion mutant in the ssrB overexpressing mutant background

This study

T3SS2⁺ ∆sseJ-pSseJ-2HA

sseJ single deletion mutant in the ssrB overexpressing mutant background complemented with pSseJ-2HA

This study

T3SS2⁺ ∆sseF

sseF single deletion mutant in the ssrB overexpressing mutant background

This study

T3SS2⁺ ∆sseF-pSseF-2HA

sseF single deletion mutant in the ssrB overexpressing mutant background complemented with pSseF-2HA

This study

T3SS2⁺ pACYC-2HA

ssrB overexpressing mutant transformed with pACYC184 containing a 2xHA tag under the control of the native promoter for pipB2 expression

This study