Abstract: The recombinant plasmid pRE112-ΔacrR was constructed by amplifying the upstream and downstream homologous arms of acrR gene from the genomic DNA of Aeromonas veronii C4 and ligating them into the suicide plasmid pRE112. Subsequently the recombinant plasmid was transformed into E. coli WM3064, and mobilized into A. veronii to select the acrR gene knockout strain. Biofilm assay and growth curve analysis showed that knockout of acrR gene enhanced the biofilm formation but did not affect the growth of A. veronii. This study not only provided a necessary research material for the further exploration of the functions of AcrR in A. veronii, but also shed a light on the potential roles of AcrR in biofilm formation.

Key words: acrR gene, gene knockout, biofilm, Aeromonas veronii