Delivery of an Rhs-family nuclease effector reveals direct penetration of the gram-positive cell envelope by a type VI secretion system in Acidovorax citrulli.

ABSTRACT: The type VI secretion system (T6SS) is a double-tubular nanomachine widely found in gram-negative bacteria. Its spear-like Hcp tube is capable of penetrating a neighboring cell for cytosol-to-cytosol protein delivery. However, gram-positive bacteria have been considered impenetrable to such T6SS action. Here we report that the T6SS of a plant pathogen, Acidovorax citrulli (AC), could deliver an Rhs-family nuclease effector RhsB to kill not only gram-negative but also gram-positive bacteria. Using bioinformatic, biochemical, and genetic assays, we systematically identified T6SS-secreted effectors and determined that RhsB is a crucial antibacterial effector. RhsB contains an N-terminal PAAR domain, a middle Rhs domain, and an unknown C-terminal domain. RhsB is subject to self-cleavage

SUBMITTER: Pei TT 

PROVIDER: S-EPMC10989746 | biostudies-literature | 2022 Mar

REPOSITORIES: biostudies-literature