Proteomics analysis of digestive juice from silkworm during Bombyx mori nucleopolyhedrovirus infection.

Previous studies have analyzed the midgut transcriptome and proteome after challenge with Bombyx mori nucleopolyhedrovirus (BmNPV), however little information is available on the digestive juice proteome after BmNPV challenge. This study investigated BmNPV infection-induced protein changes in the digestive juice of silkworms using shotgun proteomics and MS sequencing. From the digestive juice of normal third-day, fifth-instar silkworm larvae, 75 proteins were identified, 44 of which were unknown; from larvae 6 h after inoculation with BmNPV, 106 proteins were identified, of which 39 were unknown. After BmNPV challenge, more secreted proteins appeared that had antiviral and digestive features. GO annotation analysis clustered most proteins in the lumen into catalytic, binding, and metabolic processes. Numerous proteins were reported to have BmNPV interactions. Hsp70 protein cognate, lipase-1, and chlorophyllide A-binding protein precursor were upregulated significantly after BmNPV challenge. Levels of trypsin-like serine protease, beta-1,3-glucanase, catalase, and serine protease transcripts decreased or were not significantly change after BmNPV challenge. Taken together, these findings provided insights into the interaction between host and BmNPV and revealed potential functions of digestive juice after per os BmNPV infection.