Development of a recombinant baculovirus with dual effects to mediate V-ATPase interference by RNA in the fall armyworm Spodoptera frugiperda

The fall armyworm (FAW) Spodoptera frugiperda has rapidly spread from the American continent to many other areas and caused serious damage to local agriculture. To explore a more environmentally friendly and effective strategy to control this pest, we developed a dual-effect RNAi system based on baculovirus infection and gene silencing. V-ATPase subunits A and B of FAW (SfvATPaseA and SfvATPaseB) were cloned to construct a recombinant baculoviruses (rBviruses) of Bacmid-dsSfvATPaseA and Bacmid-dsSfvATPaseB with the capacity to produce small interfering RNA. The efficacy of baculovirus-mediated RNAi was evaluated by injection delivery. The results showed that the relative expression levels of SfvATPaseA and SfvATPaseB were significantly suppressed by the constructed rBviruses, with reduction rates of 73.85% and 69.82%, respectively. The inhibition rates of larval body weight and length resulting from RNAi were more than 82% and 40%, respectively. More importantly, these two rBviruses greatly accelerated the larval death of FAW; compared to a bacmid control, the total mortality was two days less. After ten serial passages, both rBviruses exhibited excellent genetic stabilities. These results suggest that the creation of dual-effect biopesticides with both viral infection and gene silencing activities is feasible and prospective.

Automated summary

A dual-effect RNAi system based on baculovirus infection and gene silencing was developed to control the fall armyworm. The injection of recombinant baculoviruses carrying small interfering RNA significantly suppressed the expression of target genes and reduced the body weight and length of the larvae, leading to accelerated larval death. These findings suggest the feasibility and prospects of developing biopesticides using a dual-effect RNAi system.