A Vibrio-specific T6SS effector reshapes microbial competition by disrupting Vibrio bioenergetics

Type VI secretion systems (T6SSs) are widely distributed among Vibrio species, yet their roles in the coexistence of toxigenic and non-toxigenic strains remain unclear. Here, we report an orphan T6SS effector-immunity module, T6SS effector specific to Vibrios (TseVs)-cognate immunity protein (TsiVs), primarily harbored by non-toxigenic Vibrio cholerae. TseVs exhibits robust vibriocidal activity, specifically targeting susceptible Vibrios lacking the TsiVs. TseVs forms dual-membrane, ion-selective pores that collapse Na⁺/K⁺ homeostasis, resulting in membrane depolarization and ATP depletion. Remarkably, non-Vibrio bacteria evade TseVs through proton motive force (PMF)-dependent resilience, uncovering an immunity-independent defense strategy. Furthermore, tseVs-positive non-toxigenic V. cholerae strains are globally distributed and have dominated in recent decades, highlighting TseVs's ecological significance in Vibrio population dynamics. By linking TseVs bioenergetic targeting mechanisms to Vibrio population shifts, we demonstrate how T6SS effectors shape microbial genetic diversity. Our findings suggest that TseVs represents a promising model for precision antimicrobial strategies, minimizing collateral damage to commensal microbiota.