Transcriptome sequencing to unravel the molecular mechanisms underlying the cuticle liquefaction of Antheraea pernyi following Antheraea pernyi nucleopolyhedrovirus challenge

Abstract

Baculovirus causes liquefaction of insect cuticle to enhance the dissemination of progeny virions away from the host cadavers for increasing viral transmission rates. Antheraea pernyi nucleopolyhedrovirus (ApNPV) infects A. pernyi larvae with circular pus blotches formed in cuticle in the early stage of liquefaction. To investigate the formation mechanism of those pus blotches, the transcriptome profile changes of the cuticles between ApNPV-infected and non-infected A. pernyi larvae were analyzed using RNA-Seq. The transcriptome was de novo assembled using the Trinity platform. Comparison of gene expression levels revealed that a total of 2990 and 4427 unigenes were up- and down-regulated respectively in ApNPV-infected cuticle, of which 2620 and 1903 differentially expressed genes (DEGs) could be enriched in different GO terms and KEGG pathways. In this study, we focused on chitin metabolism related DEGs, and screened 10 genes involved in chitin synthesis and degradation with down-regulated trends, indicating that the chitin metabolism pathway was inhibited by ApNPV infection, which may promote liquefaction of A. pernyi cuticle. Besides, we also identified a large number of DEGs involved in immune related pathways via KEGG analysis, indicating that intense immune responses occurred in A. pernyi cuticle. Our research findings will serve as a basis for further researching the molecular mechanisms underlying cuticle liquefaction of A. pernyi induced by ApNPV infection.