Genome wide microarray based expression profiles associated with BmNPV resistance and susceptibility in Indian silkworm races of Bombyx mori

• First report on identification of antiviral immune response in Indian silkworm races of Bombyx mori using microarray technique
• Specific focus on differential level of gene expression patterns in resistant and susceptible B. mori breeds against BmNPV
• Unraveling of immune response against BmNPV in Indian silkworm races, which are known to possess resistance character
• Identification of genes associated with viral resistance using microarray technique
• Outcome of the study can be utilized to develop disease resistance silkworm breeds through gene targeted breeding

The molecular mechanism involved in BmNPV resistance was investigated using a genome wide microarray in midgut tissue of Indian silkworm Bombyx mori. In resistant race (Sarupat), 735 genes up-regulated and 589 genes down-regulated at 12 h post BmNPV infection. Similarly, in case of susceptible race (CSR-2), 2183 genes up-regulated and 2115 genes down-regulated. Among these, nine up-regulated and eight down-regulated genes were validated using real-time qPCR analysis. In Sarupat, vacuolar protein sorting associated, Xfin-like protein and carboxypeptidase E-like protein genes significantly up-regulated in infected midgut; prominently down-regulated genes were glutamate receptor ionotropic kainite 2-like, BTB/POZ domain and transferrin. Considerably up-regulated genes in the CSR-2 were peptidoglycan recognition protein S6 precursor and rapamycin while the conspicuous down-regulated genes were facilitated trehalose transporter and zinc transporter ZIP1-like gene. The up-regulation of genes in resistant race after BmNPV infection indicates their possible role in antiviral immune response.