The opportunistic marine pathogen <i>Vibrio parahaemolyticus</i> becomes virulent by acquiring a plasmid that expresses a deadly toxin

TLDR

AHPND is a shrimp disease that has caused worldwide economic losses since 2009, and it is caused by a specific strain of *Vibrio parahaemolyticus*. The study demonstrates that opportunistic *V. parahaemolyticus* becomes highly virulent after acquiring a unique AHPND‑associated plasmid.

Abstract

Significance Since 2009, an emergent shrimp disease, acute hepatopancreatic necrosis disease (AHPND), has been causing global losses to the shrimp farming industry. The causative agent of AHPND is a specific strain of Vibrio parahaemolyticus . We present evidence here that the opportunistic V. parahaemolyticus becomes highly virulent by acquiring a unique AHPND-associated plasmid. This virulence plasmid, which encodes a binary toxin [ V. parahaemolyticus Photorhabdus insect-related toxins (PirA vp and PirB vp )] that induces cell death, is stably inherited via a postsegregational killing system and disseminated by conjugative transfer. The cytotoxicity of the PirA vp /PirB vp system is analogous to the structurally similar insecticidal pore-forming Cry toxin. These findings will significantly increase our understanding of this emerging disease, which is essential for developing anti-AHPND measures.