Genomic Sequence And Infectivity Analysis Of WSSV-CN04

White spot syndrome virus(WSSV)is one of the major pathogens that seriously obstructed the development of the shrimp acquclture.It has caused enormous economic losses to shrimp farming industry.In this study,we identified a new WSSV strain,WSSV-CN04,from naturally infected Marsupenaeus japonicus.Whole genomic sequencing indicated that WSSV-CN04 genome was 281,054 bp in length encoding 157 hypothetic proteins.Comparative genomic analysis showed that the genome of WSSV-CN04 was highly similar to that of WSSV-CN03,sharing 97.5% sequence identity.Notably,in WSSV-CN04,the major envelop protein VP24 was not only truncated but also absent in the virions.Since VP24 was previously reported to be essential for WSSV per os infection by mediating WSSV-chitin interaction,we further analyzed the peroral infection of WSSV-CN03 and WSSV-CN04 in Litopenaeus vannamei.The results indicate that due to the partial deletion of the VP24 gene in WSSV-CN04,it cannot be mapped to the envelope of the virion,whereas the VP24-deficient virion reduces the ability to bind to the chitin fraction in the digestive tract and is more likely to be discharge of the digestive tract,resulting in the virus particles in the digestive tract to reduce the residence time,reducing the virus particles through the digestive tract wall into the body of the opportunity to reflect the weaker infectivity.This study further demonstrates the important role of VP24 in WSSV per os infection through digestive tract pathways,provide new ideas for preventing WSSV infection in shrimp farms.