Potential use of a group II alphabaculovirus isolated from Mamestra brassicae as a broad-spectrum biological pesticide

A novel native isolate of Mamestra brassicae nucleopolyhedrovirus, designated MabrNPV-CHb1, was identified in this study. The complete nucleotide sequence of MabrNPV-CHb1 was determined. The MabrNPV-CHb1 genome consists of 154,451 bp, with a G + C content of 40.05%. The genomic sequence and comparative analysis indicated that MabrNPV-CHb1 shares high nucleotide identity with MabrNPV-K1, HearMNPV, MacoNPV-B and MacoNPV-A. The major difference between MabrNPV-CHb1 and MabrNPV-K1 is the absence of MabrNPV-CHb1 ORF134 in MabrNPV-K1. The MabrNPV-CHb1 ORF134 is a gene encoding a putative transposase, and phylogenetic analysis suggests that it is derived through horizontal gene transfer (HGT) from ascoviruses. MabrNPV-CHb1 exhibits broad-spectrum activity against lepidopteran agricultural pests, including insects in the families Noctuidae and Plutellidae. A high yield of MabrNPV-CHb1 occlusion bodies was obtained by propagation in alternative hosts, demonstrating its potential for pesticide application. Its broad host range, high yields in alternative hosts and clear genetic background could extend its potential applications as a broad-spectrum insecticide in the future.