Plant secondary metabolites are crucial in affecting the interactions between insect herbivores and entomoviruses. However, there is limited knowledge regarding the impact of such metabolites on the susceptibility of insect herbivores to entomoviruses. In this study, we adopted the allicin, caterpillars (Spodoptera exigua) and nucleopolyhedrovirus (SeMNPV) as a system, and found that allicin significantly increased the mortality of S. exigua larvae infected with SeMNPV by 36.03–59.45% when infected with the virus at a concentration of 2.12 × 10³ OB·mL⁻¹. Furthermore, NPV-infected larvae together treated with allicin inhibited the growth and development of larvae, comparing to individual NPV-infected larvae. Notably, we observed a significant enrichment of differentially expressed genes involved in the cytochrome P450-mediated metabolism pathway between the NPV-infected and allicin combined with NPV-treated groups. The silencing of CYP340AA1 through RNA interference significantly increased the mortality of larvae infected with SeMNPV. This investigation indicates that allicin might be a potential candidate for improving the performance of the NPV against insect herbivores and identifies that CYP340AA1 gene is important in this process.

植物次生代谢产物对于影响昆虫食草动物和昆虫病毒之间的相互作用至关重要。然而，关于此类代谢物对昆虫食草动物对昆虫病毒敏感性的影响的知识有限。在本研究中，我们以大蒜素、甜菜夜蛾（ Spodoptera exigua ）和核多角体病毒（SeMNPV）为系统，发现大蒜素显着增加了感染SeMNPV的甜菜夜蛾幼虫在感染病毒后的死亡率，提高了36.03%~59.45%。浓度为2.12×10 ³ OB·mL ^-1 。此外，与单独感染NPV的幼虫相比，用大蒜素一起处理感染NPV的幼虫抑制了幼虫的生长和发育。值得注意的是，我们观察到 NPV 感染组和大蒜素联合 NPV 治疗组之间参与细胞色素 P450 介导的代谢途径的差异表达基因显着富集。通过RNA干扰沉默CYP340AA1显着增加了感染SeMNPV的幼虫的死亡率。这项研究表明大蒜素可能是提高 NPV 对抗食草昆虫性能的潜在候选者，并确定 CYP340AA1 基因在此过程中很重要。