Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Key Laboratory of Forest Protection of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing 100091, China.
Int J Mol Sci. 2023 Feb 9;24(4):3464. doi: 10.3390/ijms24043464.
Natural enemies such as parasitoids and parasites depend on sensitive olfactory to search for their specific hosts. Herbivore-induced plant volatiles (HIPVs) are vital components in providing host information for many natural enemies of herbivores. However, the olfactory-related proteins involved in the recognition of HIPVs are rarely reported. In this study, we established an exhaustive tissue and developmental expression profile of odorant-binding proteins (OBPs) from , an essential natural enemy in the forestry ecosystem. Twenty DhelOBPs displayed various expression patterns in different organs and adult physiological states, suggesting a potential involvement in olfactory perception. In silico AlphaFold2-based modeling and molecular docking showed similar binding energies between six DhelOBPs (DhelOBP4, 5, 6, 14, 18, and 20) and HIPVs from . While in vitro fluorescence competitive binding assays showed only recombinant DhelOBP4, the most highly expressed in the antennae of emerging adults could bind to HIPVs with high binding affinities. RNAi-mediated behavioral assays indicated that DhelOBP4 was an essential functional protein for adults recognizing two behaviorally attractive substances: -cymene and γ-terpinene. Further binding conformation analyses revealed that Phe 54, Val 56, and Phe 71 might be the key binding sites for DhelOBP4 interacting with HIPVs. In conclusion, our results provide an essential molecular basis for the olfactory perception of and reliable evidence for recognizing the HIPVs of natural enemies from insect OBPs' perspective.
天敌，如寄生蜂和寄生虫，依赖敏感的嗅觉来寻找特定的宿主。植物挥发物（HIPVs）是许多植食性天敌寻找宿主信息的重要组成部分。然而，涉及识别 HIPVs 的嗅觉相关蛋白却很少被报道。在这项研究中，我们建立了一个详尽的组织和发育表达谱，研究了森林生态系统中重要天敌 中的气味结合蛋白（OBPs）。20 个 DhelOBPs 在不同器官和成虫生理状态中表现出不同的表达模式，这表明它们可能参与了嗅觉感知。基于 AlphaFold2 的计算机建模和分子对接表明，DhelOBP4、5、6、14、18 和 20 这 6 个 DhelOBP 与 中的 HIPVs 之间具有相似的结合能。然而，体外荧光竞争结合实验仅显示重组 DhelOBP4 与 HIPVs 具有高结合亲和力，而 DhelOBP4 是成虫触角中表达量最高的蛋白。RNAi 介导的行为测定表明，DhelOBP4 是成虫识别两种具有行为吸引力的物质：-柠檬烯和γ-萜品烯的必需功能蛋白。进一步的结合构象分析表明，Phe54、Val56 和 Phe71 可能是 DhelOBP4 与 HIPVs 相互作用的关键结合位点。综上所述，我们的研究结果为 嗅觉感知提供了重要的分子基础，并从昆虫 OBPs 的角度为识别天敌的 HIPVs 提供了可靠的证据。
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