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. 2020 Feb 5;10:3077. doi: 10.3389/fmicb.2019.03077

FIGURE 1.

FIGURE 1

Agrobacterium tumefaciens type VI secretion system (T6SS)-dependent antibacterial activity against Escherichia coli strains. (A,B) A. tumefaciens T6SS antibacterial activity against E. coli strains DH10B and BW25113. A. tumefaciens was co-cultured at a ratio of 30:1 with E. coli DH10B or BW25113, both E. coli strains harboring vector pRL662, on Agrobacterium Kill (AK) agar medium for 16 h. The bacterial mixtures were serially diluted and spotted (A) or quantified by counting cfu (B) on gentamicin-containing lysogeny broth (LB) agar plates to selectively recover E. coli. (C) E. coli DH10B was complemented by either vector only (vec) or derivative expressing rpsL, galK, nupG, or rpsLStr in trans before being subjected to A. tumefaciens T6SS-dependent antibacterial activity assay as described in (B). Susceptibility index (SI) was defined as the subtraction difference of the recovery log(cfu) of that attacked by ΔtssL to that attacked by wild-type A. tumefaciens C58. Data are mean ± SD of three independent experiments calculated by t-test with P < 0.05 for statistical significance (B) or single-factor analysis of variance (ANOVA) and Tukey honestly significant difference (HSD), in which two groups with significant differences are indicated with different letters (a and b) (C).