Specific Response And Resistance Mechanism Of Bombyx Mori C-type Lectin BmS7 To BmNPV

Bombyx mori nuclear polyhedrosis virus(BmNPV)disease is a major infectious disease in the sericulture industry.There is currently no good solution.In the anti-BmNPV immune mechanism of silkworm,the pattern recognition receptor is an important pathway for virus-infected cells.C-type lectin is one of the major pattern recognition receptors in many insects innate immunity,and is increasingly considered to be immune to disease resistance.It plays an important role in whether or not silkworm has this immune system.In this study,BmNPV was added by silkworm,qRT-PCR was used to detect the BmS7 gene of silkworm C-type lectin and the gene expression of BmS7-mediated innate immune signaling pathway,and the specificity of response to BmNPV infection was studied.The results can be cultivated.Technical references for disease-resistant varieties.1.BmNPV induces specific expression of C-type lectin BmS7 in silkwormBombyx mori was supplemented with BmNPV and BmCPV,and Staphylococcus aureus and Escherichia coli were injected.The BmS7 gene 'of silkworm C-type lectin was detected by qRT-PCR.The results showed that only silkworm infected BmNPV in silkworm midgut,fat body and hemolymph tissue,silkworm The transcription level of the C-type lectin BmS7 is highly upregulated.It is speculated that the expression of BmS7 gene in the silkworm C-type lectin is unique to BmNPV infection.The consistent results of different varieties of silkworms further suggest that the abnormal expression of BmS7 gene in the silkworm C-type lectin is a specific response to BmNPV infection.2.The position of the silkworm C-type lectin BmS7 protein in cellsThe C-type lectin BmS7 gene in the midgut cells of silkworms changed at the protein level after infection with BmNPV.After BmNPV infection in silkworm,the expression of BmS7 protein in the midgut cells was much higher than that in the uninfected silkworm.It was speculated that the mRNA and functional proteins of BmS7 were synchronously increased after BmNPV infection.Immunofluorescence labeling assay showed that the C-type lectin BmS7 protein was concentrated in the inner side of the cell membrane,suggesting that the C-type lectin BmS7 protein acts as a pattern recognition receptor.Although there is no transmembrane domain,it is predicted to predict the C-type lectin BmS7.Proteins are downstream signaling proteins of receptors on the cell membrane.3.Resistance of BmNPV to the silkworm C-type lectin BmS7 and its mediated immune pathwayInjecting dsRNA into the silkworm dorsal vein interfered with the expression of BmS7 gene of silkworm C-type lectin,and then infected BmNPV,and found that the incidence of silkworm increased,and the ability of silkworm to resist BmNPV decreased.qRT-PCR results showed that BmS7 gene of silkworm C-type lectin The expression was down-regulated and the viral load was elevated.It is predicted that the BmS7 gene plays an important role in the process of BmNPV infection.The expression of target genes in Toll,IMD and JAK/STA,which may be mediated by the BmS7 gene,It shows that there are only significant differences in the impact of the IMD pathway.