Fig. 4.

Effect of VgrG2 C-terminal truncation on type VI secretion and Tde2-dependent interbacterial competition activity. (A) Amino acid sequence of VgrG2 C-terminal variable region is shown with the indicated residue number, and the predicted β-strands and loops are marked with blue solid arrows and lines, respectively. VgrG2 C-terminal truncated variants are shown with yellow bars, and the numbers in parentheses represent the terminal amino acid of each variant. Presence (+) or absence (–) of Hcp and Tae secretion and Tde2-dependent antibacterial activity is based on Fig. 3 B and C. (B) Western blot analysis of total (T) and secreted (S) protein from A. tumefaciens ∆vgrG1∆vgrG2 expressing the plasmid control (p) or indicated plasmid. Protein names and molecular weight markers are indicated at the left and right, respectively. The soluble ActC protein was an internal nonsecreted protein control. (C) Effect of VgrG2 C-terminal truncation on Tde2-dependent interbacterial competition activity. Various A. tumefaciens strains shown on the x axis were mixed with ∆tde2-tdi2 at a 10:1 ratio and infiltrated into N. benthamiana leaves. The survival of ∆tde2-tdi2 collected at 0 and 24 h was quantified as cfu. Data are mean ± SEM (n = 5 biological repeats from two independent experiments). Significant difference compared with ∆vgrG1∆vgrG2 (∆G1∆G2) at 24-h postinfiltration (*P ≤ 0.01). vgrG1 and vgrG2 are abbreviated as G1 and G2, respectively.