Construction of a BmNPV Polyhedrin-plus Bac-to-Bac System for the Silkworm,Bombyx mori

Usually the recombinant baculovirus was generated through replacing the foreign gene into the polyhedrin locus resulting in a polyhedrin-negative virus. Such polh-negative baculovirus can infect insect cell lines well and insect also through subcutaneous injection, but is less infective to silkworm through per oral ingestion. In order to improve the inoculation efficiency, a polyhedrin-plus Bac-to-Bac expression system for application in silkworm was constructed in this paper. Using this new system, the foreign gene and polyhedrin were both expressed at higher level and large amount of polyhedra were formed. Thereby the recombinant baculovirus can infect silkworm larva by oral administration. This new system also widen the application of baculovirus in the field of biological insecticide, gene therapy and other aspects.