State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
Insect Sci. 2021 Dec;28(6):1766-1779. doi: 10.1111/1744-7917.12894. Epub 2021 Jan 18.
Baculoviruses are natural enemies of agricultural and forest insect pests and play an important role in biological pest control. Oral infection by baculovirus in the insect midgut is necessary for establishing systemic infection and eventually killing the insect. Since the insect midgut continuously encounters microbiota, the gut microbiota could affect baculovirus infection. Here, we demonstrated that gut microbiota modulates immune responses and promotes baculovirus infection in the cotton bollworm, Helicoverpa armigera. After oral infection, numerous host immunity-related genes including genes encoding Toll and immune deficiency (IMD) pathway components were upregulated in the midgut. Elimination of the gut microbiota significantly increased the resistance to viral infection in H. armigera. Quantitative real-time reverse transcription polymerase chain reaction and proteomic analysis showed that downregulation of the antiviral factor prophenoloxidase (PPO) could be mediated by microbiota during infection. It implied that midgut microbiota diminishes the expression of PPO to facilitate viral infection in H. armigera. Our findings revealed that the microbiota plays an important role in modulating the resistance of H. armigera to baculovirus infection, providing new insights in applying biopesticide.
杆状病毒是农业和森林害虫的天然天敌，在生物防治中发挥着重要作用。昆虫中肠通过口服感染杆状病毒是建立系统感染并最终杀死昆虫所必需的。由于昆虫中肠不断接触微生物群，肠道微生物群可能会影响杆状病毒的感染。在这里，我们证明了肠道微生物群可以调节免疫反应并促进棉铃虫 Helicoverpa armigera 杆状病毒的感染。在口服感染后，大量与宿主免疫相关的基因，包括编码 Toll 和免疫缺陷（IMD）途径成分的基因，在中肠中被上调。消除肠道微生物群会显著增加棉铃虫对病毒感染的抵抗力。实时定量逆转录聚合酶链反应和蛋白质组学分析表明，在感染过程中，微生物群可以介导抗病毒因子酚氧化酶（PPO）的下调。这意味着中肠微生物群减少了 PPO 的表达，从而促进了 H. armigera 中杆状病毒的感染。我们的研究结果表明，微生物群在调节 H. armigera 对杆状病毒感染的抗性方面起着重要作用，为生物农药的应用提供了新的见解。
