PDF(Pubmed)
Abstract：
Aphidius gifuensis is the dominant parasitic natural enemy of aphids. Elucidating the molecular mechanism of host recognition of A. gifuensis would improve its biological control effect. Chemosensory proteins (CSPs) play a crucial role in insect olfactory systems and are mainly involved in host localization. In this study, a total of nine CSPs of A. gifuensis with complete open reading frames were identified based on antennal transcriptome data. Phylogenetic analysis revealed that AgifCSPs were mainly clustered into three subgroups (AgifCSP1/2/7/8, AgifCSP3/9, and AgifCSP4/5/6). AgifCSP2/5 showed high expression in the antennae of both sexes. Moreover, AgifCSP5 was found to be specifically expressed in the antennae. In addition, fluorescent binding assays revealed that AifCSP5 had greater affinities for 7 of 32 volatile odor molecules from various sources. Molecular docking and site-directed mutagenesis results revealed that the residue at which AgifCSP5 binds to these seven plant volatiles is Tyr75. Behavior tests further confirmed that trans-2-nonenal, one of the seven active volatiles in the ligand binding test, significantly attracted female adults at a relatively low concentration of 10 mg/mL. In conclusion, AgifCSP5 may be involved in locating aphid-infested crops from long distances by detecting and binding trans-2-nonenal. These findings provide a theoretical foundation for further understanding the olfactory recognition mechanisms and indirect aphid localization behavior of A. gifuensis from long distances by first identifying the host plant of aphids.
摘要：
蚜虫是蚜虫的主要寄生天敌。阐明紫菜宿主识别的分子机制将提高其生物防治效果。化学感觉蛋白（CSP）在昆虫嗅觉系统中起着至关重要的作用，并且主要参与宿主定位。在这项研究中,根据触角转录组数据，总共鉴定了9个具有完整开放阅读框的双歧杆菌CSP。系统发育分析表明，AgifCSP主要分为三个亚组（AgifCSP1/2/7/8，AgifCSP3/9和AgifCSP4/5/6）。AgifCSP2/5在两性的触角中均显示出高表达。此外，发现AgifCSP5在触角中特异性表达。此外,荧光结合测定显示，AifCSP5对来自各种来源的32种挥发性气味分子中的7种具有更大的亲和力。分子对接和定点诱变结果表明，AgifCSP5与这7种植物挥发物结合的残基是Tyr75。行为测试进一步证实，反式-2-壬烯，配体结合试验中的七种活性挥发物之一,在相对较低的10mg/mL浓度下显着吸引女性成年人。总之,通过检测和结合反式2-壬烯醛，AgifCSP5可能参与远距离定位蚜虫感染的作物。这些发现为通过首次识别蚜虫的寄主植物，进一步从远距离了解吉夫草的嗅觉识别机制和间接蚜虫定位行为提供了理论基础。
