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Elucidation of Insect Olfaction in the Pea Aphid, Acyrthosiphon pisum

豌豆蚜 Acyrthosiphon pisum 昆虫嗅觉的阐明

基本信息

批准号：
1804053
负责人：
金额：
--
依托单位：
University of Nottingham
依托单位国家：
英国
项目类别：
Studentship
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=studentship-1804053
关键词：
Elucidation Insect Olfaction Pea Aphid

项目摘要

Aphids (Homoptera: Aphididae) are the major pests of arable and horticultural crops in Western and Northern Europe, causing direct damage through their feeding or indirectly through the transmission of plant pathogens eg Barley Yellow Dwarf Virus (BYDV). The sex pheromone components of the pea aphid, Acyrthosiphon pisum, comprise of a mixture of two iridoids (cyclopentanoids), (4aS,7S,7aR)-nepetalactone and (1R,4aS,7S,7aR)-nepetalactol that are emitted by females during the sexual phase of their life cycle. Male aphids are attracted to the sex pheromone and respond to the ratio of the pheromone components in a species-specific manner. Their enantiomers, (4aR,7R,7aS)-nepetalactone and (1S,4aR,7R,7aS)-nepetalactol are not naturally-occurring and do not possess biological activity although they have the same physical and chemical properties as the sex pheromone components and only differ in their three-dimensional structure as mirror images. A. pisum can serve as a tractable model system for investigation of the mechanisms underlying molecular recognition of odorants in animals because of (i) already identified odorants, in particular sex pheromone components described above Nat. Prod. Rep. 2013, 30:1277-1283 (ii) recent advances in the annotation of the pea aphid genome, specifically olfactory proteins that can recognise and discriminate between different odorants (PLoS Biol 2010, 8: e1000313; Insect Mol. Biol. 2010, 19:113-122 and (iii) readily accessible olfactory organs, i.e., aphid antennae. Despite the crucial role that olfaction plays in aphid biology, it has not been possible to elucidate and discriminate unequivocally between two hypotheses underlying the molecular recognition mechanisms underpinning olfactory perception at the peripheral level, ie. (i) odorants directly activate odorant receptors (ORs) (Hypothesis A), and (ii) ORs are activated by odorant-binding protein (OBP)-odorant complexes (Hypothesis B). This project seeks to use a multi-disciplinary approach including molecular biology, electrophysiology and analytical/synthetic organic chemistry to test the two hypotheses showing whether or not there is an essential role for OBPs in determining specific molecular recognition of odorants. Male-antenna specific OR and OBP genes in the A. pisum genome will be identified and quantified using real time RT-qPCR. Male-specific OR genes will be functionally expressed in Xenopus oocytes for functional characterisation with a two electrode voltage clamp technique (PLoS One 2013, 8:e62098). The non-natural enantiomers of the sex pheromone components will be synthesized and used to explore enantiomer discrimination at the OR level. The specificity and response kinetics of male ORs to aphid sex pheromone components and their enantiomers will be measured with and without OBPs. The ability of male-antenna specific OBPs to discriminate enantiomers will be measured using an established high-throughput ESI-MS assay to be done by a collaborating lab (Dr Ales Svatos, Max-Planck Institute for Chemical Ecology, Jena.

蚜虫（同翅目：蚜虫（Aphididae）是西欧和北方的主要农作物和园艺作物害虫，通过取食或通过传播植物病原体如大麦黄矮病毒（BYDV）间接造成危害。豌豆蚜Acyrthosiphon pisum的性信息素组分由两种环烯醚萜类（环戊醇类）（（4aS，7S，7aR）-荆芥内酯和（1 R，4aS，7S，7aR）-荆芥内酯醇）的混合物组成，其由雌性在其生命周期的有性阶段期间释放。雄性蚜虫被性信息素吸引，并以种特异性方式对信息素组分的比例作出反应。它们的对映异构体（4aR，7 R，7aS）-荆芥内酯和（1 S，4aR，7 R，7aS）-荆芥内酯醇不是天然存在的，不具有生物活性，尽管它们具有与性信息素组分相同的物理和化学性质，只是它们的镜像三维结构不同。A.豌豆可用作研究动物中气味剂分子识别机制的易处理模型系统，这是因为（i）已经鉴定的气味剂，特别是上述性信息素组分。Rep. 2013，30：1277-1283（ii）豌豆蚜虫基因组注释的最新进展，特别是可以识别和区分不同气味剂的嗅觉蛋白（PLoS Biol 2010，8：e1000313; Insect Mol. 2010，19：113-122和（iii）容易接近的嗅觉器官，即，蚜虫触角尽管嗅觉在蚜虫生物学中起着至关重要的作用，但在外周水平上支持嗅觉感知的分子识别机制（即嗅觉）的两种假设之间还不能明确地阐明和区分。(i)气味直接激活气味受体（OR）（假设A），和（ii）OR被气味结合蛋白（OBP）-气味复合物激活（假设B）。本项目旨在利用分子生物学、电生理学和分析/合成有机化学等多学科方法来验证两个假设，以表明OBP在确定气味物质的特定分子识别方面是否起着重要作用。雄触角特异的OR和OBP基因在A.将使用真实的时间RT-qPCR鉴定和定量豌豆基因组。雄性特异性OR基因将在非洲爪蟾卵母细胞中功能性表达，用于用双电极电压钳技术进行功能表征（PLoS One 2013，8：e62098）。性信息素组分的非天然对映体将被合成并用于探索在OR水平上的对映体辨别。雄性ORs对蚜虫性信息素组分及其对映体的特异性和反应动力学将在有和没有OBP的情况下进行测量。雄性触角特异性OBP区分对映异构体的能力将使用由合作实验室完成的已建立的高通量ESI-MS测定来测量（Dr Ales Svatos，Max-Planck Institute for Chemical Ecology，Jena.