Effects of bm47 Deletion on Viral Replication and Transcription of Bombyx Mori Nucleopolyhedrovirus

Bombyx mori nucleopolyhedrovirus(BmNPV)bm47gene is found in all sequenced lepidopteran nucleopolyhedroviruses(NPVs).It is one of the core genes of NPVs.However,the role of bm47in the biological cycle of NPV remains unknown.In this study,the Red recombination system was used to knock out bm47from BmNPV to construct bm47-ko-Bacmid in E.coli BW25113system.Then bm47gene was introduced back to the viral genome using the Bac-to-Bac system to create the repair virus bm47-re-Bacmid. TCID50assay and real-time PCR(qPCR)were used to evaluate the effects of bm47deletion on viral DNA replication,gene transcription,and protein expression.qPCR results showed that bm47knock-out had no significant effect on viral DNA replication.However,the qPCR results showed that bm47-ko-Bacmid significantly decreased the transcription levels of early gene lef-3,late gene vp39,and very late gene p10at 48 h and 72hafter viral transfection of BmN cells(P0.05).This work will provide a foundation for further studies on the biological function of BmNPVbm47in viral replication and transcription.