Knockout of two alanine racemase genes of Vibrio anguillarum and its potential as an attenuated vaccine in olive flounder (Paralichthys olivaceus)

In this paper, we generated auxotrophic Vibrio anguillarum mutants by knockout of alanine racemase genes, and evaluated their potential as a prophylactic vaccine in olive flounder. The results of the vaccine experiment showed that the survival rate and serum agglutination titer of fish immunized with 1 × 105 CFU/fish of Δalr1Δalr2 V. anguillarum were significantly higher than fish immunized with 1 × 105 CFU/fish of FKC V. anguillarum, suggesting that Δalr1Δalr2 V. anguillarum can elicit protective immune responses more efficiently than FKC V. anguillarum.