Myricetin inhibits Micropterus salmoides rhabdovirus infection by damping inflammation through the NF-κB pathway

Largemouth bass have been plagued by diseases elicited by bacteria, parasites, and viruses, particularly viral diseases, which have caused significant economic losses in recent years. And there is a lack of approved antiviral drugs in the aquaculture industry. Micropterus salmoides Rhabdovirus (MSRV) is the causative agent of Micropterus salmoides Rhabdovirus disease, which mostly affects largemouth bass fry. By using experimental infection, transcriptome sequencing, and inhibitor treatment, the inflammatory response mediated by mitogen-activated protein kinase (MAPK), phosphatidylinositol3-kinase (PI3K), and nuclear factor kappa-B (NF-κB) pathways was verified as one of the pathological processes of MSRV infection. Further, Myricetin, arteannuin, naringenin, ursolic acid, andrographolide, and resveratrol were selected to evolute their anti-inflammatory activity based on the promoter of NF-κB and found myricetin, naringenin, andrographolide, and resveratrol significantly inhibited NF-κB 1 promoter activity. Myricetin was found to damp MSRV caused-inflammation and inhibit MSRV infection by suppressing NF-κB signaling. Besides, myricetin improves the survival rate of largemouth bass after MSRV infection. In conclusion, myricetin presented anti-MSRV activity by targeting the NF-κB inflammatory pathway and can be further developed as a potential preventative drug of rhabdovirus disease.