clpV is a key virulence gene during in vivo Pseudomonas plecoglossicida infection

Abstract Interaction between bacterial pathogen and aquatic animal host is exceedingly complex, which involves large dynamic changes in gene expression during different stages of the disease. However, research on identifying key virulence genes based on the dynamics of gene expression changes of a one‐sided bacterial pathogen in tissue has not been reported so far across different stages of infectious disease. The clpV for the T6SS of Pseudomonas plecoglossicida was identified for a candidate for key virulence gene based on dynamic changes of gene expression. For the Epinephelus coioides infected using clpV ‐RNAi strain, no deaths were observed up to 20 dpi. The spleens, kidneys and livers of all the E. coioides that received clpV ‐RNAi strain failed to develop visible nodules at 5–8 dpi, with the swelling gradually disappearing. The burdens of clpV ‐RNAi strain in the spleen and blood were greatly reduced at most of the time points after injection, and the burdens of clpV ‐RNAi strain in the head kidneys and trunk kidneys also had a sharp reduction from 72 to 120 hpi. This paper provides a new insight into the discovery of key virulence genes of pathogens in infected tissue systems.