Characterization and pathogenicity of acute hepatopancreatic necrosis disease natural mutants, pirABvp (‐) V. parahaemolyticus, and pirABvp (+) V. campbellii strains
文摘
A composite transposon, named Tn6264, consists of pirABvp genes and the flanking insertion sequence (ISVal1), is associated with AHPND of shrimp. Two types of pirABvp deletion mutants of V. parahaemolyticus were found in the AHPND-affected farms. The type I mutants, named pirABvp(-), have deletions (4.4-kb or 6.0-kb) of entire pirABvp genes and the downstream ISVal1. The type II mutants, named pirAvp(-), have smaller deletions (1.5-kb or 1.6-kb) of pirAvp and including a partial pirBvp. V. campbellii strains carrying pirABvp genes were found, through laboratory bioassays and histologicial evaluation, to cause AHPND.