Fig. 4.

T6SS2 is necessary for killing. (A) CFU counts for each coincubation spot for coincubations of ES114 with FQ1 wild-type, vasA_1 mutant, vasA_2 mutant, vasA_2 mutant with IPTG-inducible vasAB_2 complement plasmid, and (C) ES114 with FQ2 and EBS wild-type and vasA_2 mutant strains and corresponding fluorescence microscopy images of ES114 at 15 h. (Scale bars, 2 mm.) All experiments were performed at least three times and a representative experiment (n = 4) is shown. Asterisks indicate P < 0.05 (Student’s t test) indicating a statistically significant decrease in ES114 CFUs at 5 h compared with 0 h for each coincubation. (B) Fluorescence microscopy images of FQ-A001 strains (wild-type, vasA_1 mutant, and vasA_2 mutant) with IPTG-inducible vipA_2::gfp fusion plasmid were taken after 2 h on LBS agar pads supplemented with 0.5 mM IPTG. White arrows indicate T6SS2 sheaths. (Scale bar, 1 µm.)