AcMNPV, a viral insecticide of Lepidoptera pests, stimulates the immune response of the natural enemy Arma chinensis Fallou.

Abstract

Autographa Californica multiple nucleopolyhedrovirus (AcMNPV) is the most widely studied baculovirus currently used as a biopesticide application for crop pest control. AcMNPV has a good control effect on Lepidoptera pests, but the impact of AcMNPV on other insects in the environment, especially natural enemies, is worth further discussion. Arma chinensis Fallou, an essential natural enemy insect widely distributed in China, can prey on multiple pests that cause severe damage to the production economy and can play an effective role in preventing agroforestry pests. In this study, the natural enemy Arma chinensis Fallou was used as the research material to analyze the effect of AcMNPV on the immune system of Arma chinensis Fallou. The immune mechanism of AcMNPV-EGFP in infecting A. chinensis was revealed for the first time, and the critical factor miR-8 was found. The relationship between AcMNPV, miR-8, and A. chinensis was described. RNAi pathway and JAK/STAT signaling pathway are the main antiviral pathways in insects, and we have newly discovered the molecular regulation mechanism of the Toll signaling pathway in antiviral immunity. In a word, AcMNPV, a Lepidopteran insecticide, affects the immune response of Arma chinensis Fallou and has side effects on natural enemies in the process of pest control.IMPORTANCEAcMNPV is a viral pesticide that is widely used to control Lepidoptera pests. However, the impact on other insects has yet to be thoroughly studied. Therefore, the toxicity and side effects of AcMNPV on non-target organisms need to be effectively evaluated. As a biological control agent in agricultural ecosystems, natural enemy insects can effectively control the number of pests and reduce crop damage. Compared with chemical pesticides, natural enemy insects can avoid or reduce pesticide residues in agricultural products and have no environmental pollution, and pests do not quickly develop resistance to them. It will help ensure crops' safe production and balance the ecosystem. In this study, AcMNPV-EGFP was used to infect the natural enemy-Arma chinensis Fallou, which proved the effect of the virus pesticide on Arma chinensis Fallou. This work helps optimize the joint use of the natural enemy-Arma chinensis Fallou and other insecticides in applying biological control and also provides a reference for understanding the mechanism of insect antiviral infection.