FIG 6.

FleR and RetS repress the activity of H1-T6SS independently. (A) Relative expression of tse1 measured by RT-qPCR in the PAO1, ΔfleR, ΔretS, and ΔfleR ΔretS strains. (B) Western blot analysis of Tse1-His in the cell-associated protein fractions from the strains of PAO1, ΔfleR, ΔretS, and ΔfleR ΔretS. (C) Bacterial killing assay between the indicated PAO1 strains and the E. coli prey. (D) Relative expression of fleR and retS in the PAO1, ΔfleR, and ΔretS strains. Data are represented as the mean ± SD (n = 3). **, P < 0.01; ***, P < 0.001 versus PAO1(EV) based on one-way ANOVA. N.D., not detected; EV, empty vector for the control.