Great effect of porin(aha) in bacterial adhesion and virulence regulation in Aeromonas veronii

Aeromonas veronii is a serious pathogen which can infect mammals and aquatic organisms and causes irreparable damage to fish aquaculture. It has been demonstrated that adhesion to host surface and cells is the initial step in bacterial pathogenesis. Previous study found that bacterial weaken motility probably caused by the absence of flagellar related genes. In this study, we generated the aha deletion and complementary strains and found that two strains can be stably inherited for more than 50 generations. No significant change was found in the growth of mutant △aha. But the ability of biofilm formation, the adhesion and invasion to EPC cells significantly decreased for 3.7-fold and 2.3-fold respectively. Due to aha gene deletion, the stability of A. veronii flagellar was severely declined and the mutant △aha with no mobility. Compared with the wild-type TH0426, the pathogenicity of A. veroniiaha-deleted strain to zebrafish and mice reduced significantly and virulence attenuated severely. Cytotoxicity experiment also proved that mutant △aha showed much weaker virulence at the same time infection. The consequences declared that the stability of flagellar decreased severely with porin missing and lost the motility. Porin regulated by aha gene is essential for the adhesion and virulence of A. veronii. Thence, the mutant △aha of A. veronii provides an important tool for further concentration on the pathogenic mechanism of A. veronii.