biostudies-literatureUnknown16(5)Lai XAcademia SinicaDiguanylate cyclases (DGCs) synthesize bis-(3',5')-cyclic diguanylic acid (c-di-GMP), a critical bacterial second messenger that coordinates diverse biological processes. <i>Agrobacterium tumefaciens</i>, a plant pathogen causing crown gall disease, relies on type IV secretion system for pathogenesis and type VI secretion system (T6SS) for interbacterial competition. Our study identified two putative DGCs, named <u>d</u>iguanylate <u>c</u>yclase domain proteins regulating <u>v</u>irulences A and B (DcvA and DcvB), that negatively regulate virulence through distinct mechanisms. DcvA suppresses virulence by targeting the VirA/VirG two-component system downstream of VirA. This inhibition is independent of c-di-GMP levels. DcvB positively regulates biofilm formation, inhibits T6SS-mediated intmBioe0003925https://www.ebi.ac.uk/biostudies/studies/S-EPMC12077199biostudies-literatureDistinct strategies of diguanylate cyclase domain proteins on inhibition of virulence and interbacterial competition by agrobacteria.PMC12077199Lai XYu MCheng C-PLai E-MfalseDistinct strategies of diguanylate cyclase domain proteins on inhibition of virulence and interbacterial competition by agrobacteria.Diguanylate cyclases (DGCs) synthesize bis-(3',5')-cyclic diguanylic acid (c-di-GMP), a critical bacterial second messenger that coordinates diverse biological processes. <i>Agrobacterium tumefaciens</i>, a plant pathogen causing crown gall disease, relies on type IV secretion system for pathogenesis and type VI secretion system (T6SS) for interbacterial competition. Our study identified two putative DGCs, named <u>d</u>iguanylate <u>c</u>yclase domain proteins regulating <u>v</u>irulences A and B (DcvA and DcvB), that negatively regulate virulence through distinct mechanisms. DcvA suppresses virulence by targeting the VirA/VirG two-component system downstream of VirA. This inhibition is independent of c-di-GMP levels. DcvB positively regulates biofilm formation, inhibits T6SS-mediated int2025-01-01T00:00:00Z2025 May2026-06-02T17:59:01.247Z2026-04-18T03:12:12.406ZS-EPMC120771994024331310.1128/mbio.00039-25