The complementation of the functional assembly of SPI-1 T3SS was also confirmed using TER assays, where the levels of decrease in resistance after infection with ΔmreC strain reverted to that of the parent strain upon induction of the transcriptional regulator hilA (Figure 9B and S9), or complementation of the ΔmreC mutation (Figure 4). Here, SPI1 is linked to infection.