Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China.
College of Forestry, Nanjing Forestry University, Nanjing, China.
Pest Manag Sci. 2023 Oct;79(10):3529-3537. doi: 10.1002/ps.7533. Epub 2023 Jun 2.
Commensal microorganisms are widely distributed in insect gut tissues and play important roles in host nutrition, metabolism, reproductive regulation, and especially immune functioning and tolerance to pathogens. Consequently, gut microbiota represent a promising resource for the development of microbial-based products for pest control and management. However, the interactions among host immunity, entomopathogen infections, and gut microbiota remain poorly understood for many arthropod pests.
We previously isolated an Enterococcus strain (HcM7) from Hyphantria cunea larvae guts that increased the survival rates of larvae challenged with nucleopolyhedrovirus (NPV). Here, we further investigated whether this Enterococcus strain stimulates a protective immune response against NPV proliferation. Infection bioassays demonstrated that re-introduction of the HcM7 strain to germfree larvae preactivated the expression of several antimicrobial peptides (particularly H. cunea gloverin 1, HcGlv1), resulting in the significant repression of virus replication in host guts and hemolymph, and consequently improved host survivorship after NPV infection. Furthermore, silencing of the HcGlv1 gene by RNA interference markedly enhanced the deleterious effects of NPV infection, revealing a role of this gut symbiont-induced gene in host defenses against pathogenic infections.
These results show that some gut microorganisms can stimulate host immune systems, thereby contributing to resistance to entomopathogens. Furthermore, HcM7, as a functional symbiotic bacteria of H. cunea larvae, may be a potential target for increasing the effectiveness of biocontrol agents against this devastating pest. © 2023 Society of Chemical Industry.
共生微生物广泛分布于昆虫肠道组织中，在宿主营养、代谢、生殖调控等方面发挥着重要作用，尤其是在宿主免疫功能和对病原体的耐受方面。因此，肠道微生物群代表了一种有前途的资源，可以开发基于微生物的产品来控制和管理害虫。然而，对于许多节肢动物害虫，宿主免疫、昆虫病原感染和肠道微生物群之间的相互作用仍知之甚少。
我们之前从舞毒蛾幼虫肠道中分离到一株肠球菌（HcM7），该菌株能提高幼虫对核型多角体病毒（NPV）的存活率。在这里，我们进一步研究了这种肠球菌菌株是否能刺激针对 NPV 增殖的保护性免疫反应。感染生物测定表明，将 HcM7 菌株重新引入无菌幼虫中，可预先激活几种抗菌肽（特别是 H. cunea gloverin 1，HcGlv1）的表达，导致病毒在宿主肠道和血液中的复制受到显著抑制，从而提高了 NPV 感染后宿主的存活率。此外，通过 RNA 干扰沉默 HcGlv1 基因显著增强了 NPV 感染的有害影响，揭示了这种肠道共生诱导基因在宿主防御病原感染中的作用。
这些结果表明，一些肠道微生物可以刺激宿主免疫系统，从而有助于抵抗昆虫病原。此外，HcM7 作为舞毒蛾幼虫的功能共生细菌，可能是提高生物防治剂对这种破坏性害虫防治效果的潜在目标。 © 2023 化学工业协会。
