biostudies-literatureBondage DDMinistry of Science and Technology, TaiwanE3931-40https://www.ebi.ac.uk/biostudies/studies/S-EPMC4941472biostudies-literatureUnknown113(27)Type VI secretion system (T6SS) is a macromolecular machine used by many Gram-negative bacteria to inject effectors/toxins into eukaryotic hosts or prokaryotic competitors for survival and fitness. To date, our knowledge of the molecular determinants and mechanisms underlying the transport of these effectors remains limited. Here, we report that two T6SS encoded valine-glycine repeat protein G (VgrG) paralogs in Agrobacterium tumefaciens C58 specifically control the secretion and interbacterial competition activity of the type VI DNase toxins Tde1 and Tde2. Deletion and domain-swapping analysis identified that the C-terminal extension of VgrG1 specifically confers Tde1 secretion and Tde1-dependent interbacterial competition activity in planta, and the C-terminal variable region of VgrG2 goProceedings of the National Academy of Sciences of the United States of AmericaVgrG C terminus confers the type VI effector transport specificity and is required for binding with PAAR and adaptor-effector complex.PMC4941472MOST 104-2311-B-001-025-MY3Lin JSLai EMMa LSBondage DDKuo CHfalseVgrG C terminus confers the type VI effector transport specificity and is required for binding with PAAR and adaptor-effector complex.Type VI secretion system (T6SS) is a macromolecular machine used by many Gram-negative bacteria to inject effectors/toxins into eukaryotic hosts or prokaryotic competitors for survival and fitness. To date, our knowledge of the molecular determinants and mechanisms underlying the transport of these effectors remains limited. Here, we report that two T6SS encoded valine-glycine repeat protein G (VgrG) paralogs in Agrobacterium tumefaciens C58 specifically control the secretion and interbacterial competition activity of the type VI DNase toxins Tde1 and Tde2. Deletion and domain-swapping analysis identified that the C-terminal extension of VgrG1 specifically confers Tde1 secretion and Tde1-dependent interbacterial competition activity in planta, and the C-terminal variable region of VgrG2 go2016-01-01T00:00:00Z2016 Jul2026-04-30T03:45:22.603Z2019-03-27T02:18:09ZS-EPMC49414722731321410.1073/pnas.1600428113