Transcriptional Responses of Daphnis nerii Larval Midgut to Oral Infection by 2 Daphnis nerii cypovirus-23

Background: Daphnis nerii cypovirus-23 (DnCPV-23) is a new type of cypovirus and has lethal effect on the oleander hawk moth, Daphnis nerii , which feeds on leave of Oleander and Catharanthus et al. After DnCPV-23 infection, the change of Daphnis nerii responses has not been reported. Methods: : In order to better understand the pathogenic mechanism of DnCPV-23 infection, 3rdinstar Daphnis nerii larvae were orally infected with DnCPV-23 occlusion bodies and the transcriptional responses of the Daphnis nerii midgut were analyzed 72 h post-infection using RNA-seq. Results: : The results showed that 1,979 differentially expressed Daphnis nerii transcripts in the infected midgut had been identified. KEGG analysis showed that protein digestion and absorption, Toll and Imd signaling pathway were down-regulated. Based on the result, it was possible the function of food digestion and absorption in insect midgut was impaired after virus infection. In addition, the down-regulation of the immune response may be conducive to viral immune escape. Glycerophospholipid metabolism and xenobiotics metabolism were up-regulated. These two types of pathways may affect the viral replication and xenobiotic detoxification of insect, respectively. Conclusion: These results may facilitate a better understanding of the changes in Daphnis nerii metabolism during cypovirus infection and serve as a basis for future research on the molecular mechanism of DnCPV-23 invasion.