Transcriptome-wide analysis of the difference of alternative splicing in susceptible and resistant silkworm strains after BmNPV infection.

Novel alternative splicing events were identified from BmNPV-susceptible and -resistant silkworm strains after BmNPV infection using high-throughput RNA-sequencing strategy. In total, 12.82 Gb clean RNA-seq data were generated for the two midgut samples from BmNPV-susceptible and -resistant silkworm strains, and 14.78 Gb clean data for the two fat body samples. The number of alternative splicing events and isoforms in the BmNPV-susceptible silkworm strain was more than that in the BmNPV-resistant silkworm strain. Furthermore, alternative splicing genes uniquely present in BmNPV-resistant silkworm strain were involved in functions about ribosome, whereas, alternative splicing genes uniquely present in BmNPV-susceptible silkworm strain were implicated in functions like DNA helicase activity and signal transduction. Additionally, 33 expressed SR or SR-like proteins were identified, and three genes encoding SR or SR-like proteins (tetratricopeptide repeat protein 14 homolog, ubiquitin carboxyl-terminal hydrolase 32 and zinc finger CCCH domain-containing protein 18) have a higher number of different alternative splicing events between two silkworm strains. The present study suggested BmNPV treatment may have a smaller effect on the mRNA transcription in BmNPV-resistant silkworms than that in BmNPV-susceptible silkworms, and functions of alternative splicing genes are different between the two silkworm strains.