Ac25 in Autographa californica multiple nucleopolyhedrovirus was crucial for progeny budded virion production

Recombinant AcMNPV-gp64-EGFP and synergist triphenyl phosphate, an effective combination against Spodoptera frugiperda

OBJECTIVES

AcMNPV is a kind of microbial insecticide that can significantly relieve the resistance of Spodoptera frugiperda to chemical pesticides. TPP is a widely used synergist, which can reduce the use of pesticides by inhibiting carboxylesterase. It is emergently needed to develop a biological control way of Spodoptera frugiperda.

RESULTS

GP64 mediates low-pH-triggered membrane fusion during entry by endocytosis and participates in AcMNPV particle budding. We explored the synergistic anti-insect activity of AcMNPV-gp64-EGFP and TPP. AcMNPV-gp64-EGFP could increase progeny virus proliferation and accelerate the transcription of 38k and vp39 genes. TPP could inhibit the carboxylesterase activity in the midgut of Spodoptera frugiperda larvae infected with AcMNPV-gp64-EGFP and enhance the virulence of AcMNPV-gp64-EGFP to Spodoptera frugiperda.

CONCLUSIONS

TPP targeted carboxylesterase inhibition so that AcMNPV-gp64-EGFP could escape the antiviral response in insect hosts. It provided a novel strategy for the prevention of Spodoptera frugiperda.

Ac106/107 affects production of infectious progeny BV by regulating transcription of late viral genes and host cell energy metabolism

BACKGROUND

AcMNPV is a model organism of baculovirus, and Spodoptera frugiperda is one of its hosts. Disclosing the role of ac106/107 in AcMNPV infecting Spodoptera frugiperda 9 (Sf9) cells is of great significance for modifying AcMNPV as a microbial insecticide. This work constructed recombinant baculovirus that knocking out, repairment and overexpression of ac106/107 and explored the effects of Ac106/107 on the proliferation of progeny viruses. Moreover, the potential mechanism and targets of ac106/107 were further revealed.

RESULTS

First, compared with the Bacmid-EGFP transfection group, the progeny virus does not proliferate after knocking out of ac106/107, and the proliferation ability increases by 14.5% at 72 h post transfection (h p.t.) when overexpression of ac106/107. However, knockout, repairment and overexpression of ac106/107 have no effect on viral DNA replication. Secondly, Ac106/107-EGFP was located in the cytoplasm and nucleus. Transcription level of late viral genes and viral RNA polymerase subunit genes in the Bacmid^ac106/107KO -EGFP transfection group and Bacmid-Ac106/107-EGFP transfection group was reduced and increased, respectively. Thirdly, AcMNPV would increase the glucose utilization and lactate consumption of the host Sf9 cells, and Bacmid^ac106/107KO -EGFP transfection group had lower glucose consumption and lactic acid accumulation than Bacmid-EGFP, Bacmid^ac106/107KO -Ac106/107(rep)-EGFP and Bacmid-Ac106/107-EGFP transfection groups.

CONCLUSION

Ac106/107 can enter the nucleus and affect transcription of viral RNA polymerase subunit genes, which in turn affects the transcription of late genes, and ultimately affects virus proliferation and energy metabolism in host cells. © 2021 Society of Chemical Industry.