The gene expression profile of resistant and susceptible Bombyx mori strains reveals cypovirus-associated variations in host gene transcript levels

Abstract

High-throughput paired-end RNA sequencing (RNA-Seq) was performed to investigate the gene expression profile of a susceptible Bombyx mori strain, Lan5, and a resistant B. mori strain, Ou17, which were both orally infected with B. mori cypovirus (BmCPV) in the midgut. There were 330 and 218 up-regulated genes, while there were 147 and 260 down-regulated genes in the Lan5 and Ou17 strains, respectively. Gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment for differentially expressed genes (DEGs) were carried out. Moreover, gene interaction network (STRING) analyses were performed to analyze the relationships among the shared DEGs. Some of these genes were related and formed a large network, in which the genes for B. mori cuticular protein RR-2 motif 123 (BmCPR123) and the gene for B. mori DNA replication licensing factor Mcm2-like (BmMCM2) were key genes among the common up-regulated DEGs, whereas the gene for B. mori heat shock protein 20.1 (Bmhsp20.1) was the central gene among the shared down-regulated DEGs between Lan5 vs Lan5-CPV and Ou17 vs Ou17-CPV. These findings established a comprehensive database of genes that are differentially expressed in response to BmCPV infection between silkworm strains that differed in resistance to BmCPV and implied that these DEGs might be involved in B. mori immune responses against BmCPV infection.

Antimicrobial Peptides as Potential Antiviral Factors in Insect Antiviral Immune Response

“…For viral diseases of silkworm, currently there is no effective treatment. Although there exist specific strains of silkworm that are resistant to some viruses, the specific mechanism is unclear ( 88 – 90 ). Like other insects, RNAi was considered as the major defense strategy against viral infections in B. mori ( 91 ).…”

Stimulator of interferon genes (STING) provides insect antiviral immunity by promoting Dredd caspase–mediated NF-κB activation

“…Expression of several antimicrobial peptides, including gloverin-1, gloverin-2, gloverin-3, gloverin-4, and lysozyme, was also induced in silkworm fat body and hemocytes by BmNPV infection (18). Gloverin has been identified as an antiviral protein combating baculovirus infection and highly expressed in BmNPV-resistant silkworm strains (19,20). Therefore, it is of interest to investigate whether activation of the NF-B signaling pathway by viral infection in insects is mediated by certain unknown molecules, such as putative STING.…”

Transcriptome analysis of interactions between silkworm and cytoplasmic polyhedrosis virus

“…With the advent of next-generation sequencing technologies, there has been a rapid development in genome-wide studies of host and virus interactions. Recently, several studies on the transcriptional response of silkworm against BmCPV challenge have been reported; these focused on differentially expressed genes 15 16 17 18 and miRNAs 19 , and host RNAi-related genes 20 . The primary issue in BmCPV study is that why this virus only infects the MG of silkworm.…”