疆夜蛾Plus-C气味结合蛋白PsauOBP7的组织表达谱及配体结合特性分析

【目的】明确疆夜蛾Peridroma saucia Plus-C气味结合蛋白PsauOBP7在不同化学感受器官中的表达谱，解析PsauOBP7重组蛋白的气味结合特异性。【方法】通过qRT-PCR检测PsauOBP7在疆夜蛾雌蛾和雄蛾的触角、口器、足和翅中的表达谱。原核表达并纯化PsauOBP7重组蛋白，利用Western blot检测PsauOBP7在疆夜蛾不同龄期幼虫头部及成虫不同组织中的表达情况；通过荧光竞争结合实验检测PsauOBP7重组蛋白对39种气味化合物的结合能力。【结果】成功表达并纯化PsauOBP7重组蛋白。qRT-PCR及Western blot检测显示PsauOBP7表达于4-6龄幼虫头部及雌雄成虫的触角、口器、足和翅中。荧光竞争结合实验显示PsauOBP7与反-2-己烯醛的结合能力最强，Ki=1.4 μmol/L。此外，PsauOBP7与5种酯类化合物乙酸月桂酯、顺-3-己烯乙酸酯、乙酸苯乙酯、苯甲酸己酯和肉桂酸甲酯有一定的结合能力，Ki值分别为5.7, 6.5, 8.9, 9.5和10.2 μmol/L。PsauOBP7与两种醇类化合物顺-3-己烯-1-醇和法尼醇也有较强的结合能力, Ki值分别为5.8和5.9 μmol/L。【结论】疆夜蛾Plus-C气味结合蛋白PsauOBP7表达于其幼虫和成虫的多种化学感受器官中，且能结合多种植物气味化合物，说明其在疆夜蛾寻找寄主植物过程中发挥重要作用。

Tissue expression profiling and ligand binding characterization of the Plus-C odorant binding protein PsauOBP7 ofPeridroma saucia(Lepidoptera: Noctuidae)

【Aim】 To clarify the expression profile of the Plus-C odorant binding protein PsauOBP7 in different chemosensory organs of the variegated cutworm, Peridroma saucia, and to analyze the odorant binding characteristics of the recombinant PsauOBP7. 【Methods】 The expression profile of PsauOBP7 in antennae, mouthparts, legs and wings of female and male moths of P. saucia was detected by qRT-PCR. The recombinant PsauOBP7 was expressed in prokaryotic expression system and purified. The expression profiles of PsauOBP7 in the head of different instar larvae and different adult tissues of P. saucia were analyzed by Western blot. The binding capabilities of the recombinant PsauOBP7 to 39 odor compounds were detected by fluorescence competitive binding assay. 【Results】 The recombinant PsauOBP7 was successfully expressed and purified. The qRT-PCR and Western blot assays showed that PsauOBP7 was expressed in the head of the 4th-6th instar larvae and the antennae, mouthparts, legs, and wings of female and male adults of P. saucia. The fluorescence competitive binding experiment showed that the binding ability of PsauOBP7 to (E)-2-hexenal was the strongest, with the Ki value of 1.4 μmol/L. In addition, PsauOBP7 had certain binding abilities to five ester compounds, dodecyl acetate, (Z)-3-hexenyl acetate, phenylethyl acetate, hexyl benzoate, and methyl cinnamate, with the Ki values of 5.7, 6.5, 8.9, 9.5, and 10.2 μmol/L, respectively. PsauOBP7 also had strong binding ability to two alcohols, (Z)-3-hexen-1-ol and farnesol, with the Ki values of 5.8 and 5.9 μmol/L, respectively. 【Conclusion】 The Plus-C odorant binding protein PsauOBP7 of P. saucia is expressed in various chemosensory organs of its larvae and adults, and can bind with a variety of plant odor compounds, suggesting that it plays an important role in searching for host plants of P. saucia.