Yongchao Guan , Meng Zhang , Yingda Wang , Zhongzhuo Liu , Zelin Zhao , Hong Wang , Dingjie An , Aidong Qian , Yuanhuan Kang , Wuwen Sun , Xiaofeng Shan
J. Microbiol. 2022;60(12):1153-1161. Published online November 10, 2022
Aeromonas veronii is a pathogen which can induce diseases in
humans, animals and aquatic organisms, but its pathogenic
mechanism and virulence factors are still elusive. In this study,
we successfully constructed a mutant strain (ΔascP) by homologous
recombination. The results showed that the deletion
of the ascP gene significantly down-regulated the expression
of associated effector proteins in A. veronii compared
to its wild type. The adhesive and invasive abilities of ΔascP to
EPC cells were 0.82-fold lower in contrast to the wild strain.
The toxicity of ΔascP to cells was decreased by about 2.91-fold
(1 h) and 1.74-fold (2 h). Furthermore, the LD50 of the mutant
strain of crucian carp was reduced by 19.94-fold, and
the virulence was considerably attenuated. In contrast to the
wild strain, the ΔascP content in the liver and spleen was considerably
lower. The titers of serum cytokines (IL-8, TNF-α,
and IL-1β) in crucian carp after the infection of the ΔascP strain
were considerably lower in contrast to the wild strain. Hence,
the ascP gene is essential for the etiopathogenesis of A. veronii
TH0426.