iTRAQ-based quantitative proteomics analysis of molecular mechanisms associated with Bombyx mori (Lepidoptera) larval midgut response to BmNPV in susceptible and near-isogenic strains

• Published in: Journal of proteomics 2017-08, Vol.165, p.35-50
• Main Authors: Yu, Haizhong, Wang, Xueyang, Xu, Jiaping, Ma, Yan, Zhang, Shangzhi, Yu, Dong, Fei, Dongqiong, Muhammad, Azharuddin
• Format: Article
• Language: English
• Subjects: Bombyx mori; Bombyx mori nucleopolyhedrovirus (BmNPV); iTRAQ; Midgut; Quantitative proteomics
• ISSN: 1874-3919
• DOI: 10.1016/j.jprot.2017.06.007

Bombyx mori nucleopolyhedrovirus (BmNPV) has been identified as a major pathogen responsible for severe economic loss. Most silkworm strains are susceptible to BmNPV, with only a few highly resistant strains thus far identified. Here we investigated the molecular basis of silkworm resistance to BmNPV using susceptible (the recurrent parent P50) and resistant (near-isogenic line BC9) strains and a combination of iTRAQ-based quantitative proteomics, reverse-transcription quantitative PCR and Western blotting. By comparing the proteomes of infected and non-infected P50 and BC9 silkworms, we identified 793 differentially expressed proteins (DEPs). By gene ontology and KEGG enrichment analyses, we found that these DEPs are preferentially involved in metabolism, catalytic activity, amino sugar and nucleotide sugar metabolism and carbon metabolism. 114 (14.38%) DEPs were associated with the cytoskeleton, immune response, apoptosis, ubiquitination, translation, ion transport, endocytosis and endopeptidase activity. After removing the genetic background and individual immune stress response proteins, we identified 84 DEPs were found that are potentially involved in resistance to BmNPV. Further studies showed that a serine protease was down-regulated in P50 and up-regulated in BC9 after BmNPV infection. Taken together, these results provide insights into the molecular mechanism of silkworm response to BmNPV. Bombyx mori nucleopolyhedrovirus (BmNPV) is highly pathogenic, causing serious losses in sericulture every year. However, the molecular mechanisms of BmNPV infection and host defence remain unclear. Here we combined quantitative proteomic, bioinformatics, RT-qPCR and Western blotting analyses and found that BmNPV invasion causes complex protein alterations in the larval midgut, and that these changes are related to cytoskeleton, immune response, apoptosis, ubiquitination, translation, ion transport, endocytosis and endopeptidase activity. Five important differentially expression proteins were validation by independent approaches. These finding will help address the molecular mechanisms of silkworm resistance to BmNPV and provide a molecular target for resisting BmNPV. [Display omitted] •Quantitative proteomics of the silkworm midgut after BmNPV infection by iTRAQ.•A total of 793 DEPs were identified after comparing the four proteomes.•Some key DEPs were validated by RT-qPCR and Western blot.•A hypothesised schematic diagram was constructed.•These data will insig