Guo Yu-Ruo, Yin Ning-Na, Wu Chun, Yang Zi-Xuan, Wang Zheng-Quan, Liu Nai-Yong
Key Laboratory of Forest Disaster Warning and Control of Yunnan Province, Southwest Forestry University, Kunming 650224, China.
Key Laboratory of Forest Disaster Warning and Control of Yunnan Province, Southwest Forestry University, Kunming 650224, China.
Comp Biochem Physiol B Biochem Mol Biol. 2023 Jun-Jul;266:110835. doi: 10.1016/j.cbpb.2023.110835. Epub 2023 Feb 15.
In the forest ecosystem dominated by the Pinaceae plants, this boring pest Dioryctria abietella is subject to a variety of odorants derived from host and nonhost plants, in which olfactory-related proteins enriched in antennae are key behavioral modulators for the orientation of feeding and ovipositing hosts. Here, we addressed the odorant binding protein (OBP) gene family in D. abietella. Expression profiles revealed that the majority of OBPs were abundantly expressed in the antennae at a female-biased level. A male-antenna-biased DabiPBP1 was a strong candidate for detecting type I and type II pheromones of D. abitella female moths. Using a prokaryotic expression system combined with affinity chromatography, we harvested two antenna-dominant DabiOBPs. In the ligand-binding assays, the two DabiOBPs exhibited different odorant response spectra, as DabiOBP17 was tuned to most odorants with higher affinities compared to DabiOBP4. Of these, DabiOBP4 could strongly bind syringaldehyde and citral (dissociation constants (K) < 14 μM). A floral volatile, benzyl benzoate (K = 4.72 ± 0.20 μM), was the best ligand for DabiOBP17. Remarkably, several green leaf volatiles were found to strongly interact with DabiOBP17 (K < 8.5 μM), including Z3-hexenyl acetate, E2-hexenol, Z2-hexenal and E2-hexenal that may mediate a repellent response to D. abietella. Structural analyses of ligands revealed that the binding of the two DabiOBPs to odorants was associated with carbon-chain lengths and functional groups. Molecular simulations identified several key residues involved in the interactions of DabiOBPs and ligands, suggesting specific binding mechanisms. This study highlights olfactory roles of two antennal DabiOBPs in D. abietella, helping the identification of potentially behavioral compounds for the population control of this pest.
在以松科植物为主的森林生态系统中，这种蛀干害虫冷杉梢斑螟会受到来自寄主植物和非寄主植物的多种气味物质的影响，其中触角中富集的嗅觉相关蛋白是其寻找取食和产卵寄主定向行为的关键调节因子。在此，我们研究了冷杉梢斑螟的气味结合蛋白（OBP）基因家族。表达谱分析表明，大多数OBP在触角中大量表达，且雌性偏向表达水平较高。雄性触角偏向表达的DabiPBP1是检测冷杉梢斑螟雌蛾I型和II型性信息素的有力候选蛋白。利用原核表达系统结合亲和层析，我们获得了两种触角优势表达的DabiOBP。在配体结合试验中，这两种DabiOBP表现出不同的气味反应谱，与DabiOBP4相比，DabiOBP17对大多数气味物质具有更高的亲和力。其中，DabiOBP4能强烈结合丁香醛和柠檬醛（解离常数（K）<14μM）。一种花香挥发物苯甲酸苄酯（K = 4.72±0.20μM）是DabiOBP17的最佳配体。值得注意的是，发现几种绿叶挥发物与DabiOBP17有强烈相互作用（K < 8.5μM），包括乙酸Z-3-己烯酯、E-2-己烯醇、Z-2-己烯醛和E-2-己烯醛，它们可能介导对冷杉梢斑螟的驱避反应。配体的结构分析表明，两种DabiOBP与气味物质的结合与碳链长度和官能团有关。分子模拟确定了参与DabiOBP与配体相互作用的几个关键残基，揭示了特定的结合机制。本研究突出了两种触角DabiOBP在冷杉梢斑螟中的嗅觉作用，有助于鉴定对该害虫种群控制具有潜在行为调控作用的化合物。
