豌豆蚜感受报警信息素的分子机制研究

发布时间：2018-06-12 20:03

本文选题：豌豆蚜 + 报警信息素　；参考：《吉林大学》2015年硕士论文

【摘要】：昆虫依靠灵敏的嗅觉系统来感知环境中特异性气味分子，进而启动相应的行为反应，例如寻找食物、寻找产卵或生殖场所、逃避天敌等。蚜虫是农业和林业上重要的害虫，其在受到外界威胁时会分泌一种报警信息素，，这种报警信息素的主要成分是(E)-β-farnesene（EBF），它不仅可以有效防止蚜虫聚集、控制蚜虫数量，而且为天敌搜寻蚜虫提供了可靠的线索。阐明蚜虫识别报警信息素的分子机制，可以为从分子水平筛选和设计比EBF更稳定的、不易挥发的蚜虫报警信息素类似物。本实验室从棉蚜和豌豆蚜基因组中鉴定了全部的气味结合蛋白和气味受体家族基因。本文建立了蚜虫RNAi干扰的方法，通过比较基因组学结合RNAi和行为测定等技术初步明确了蚜虫识别报警信息素的分子机制。主要研究结果如下： 1．明确了豌豆蚜通过嗅觉受体识别报警信息素。从豌豆蚜触角中鉴定和克隆了非典型气味受体Orco基因，研究了Orco基因的时空表达谱，明确了Orco基因主要在蚜虫触角中表达。体外合成Orco基因dsRNA，注射后72h， Orco基因相对表达量与对照相比下降了50%左右，触角电位记录结果表明注射了dsRNA的蚜虫对EBF的反应显著减弱，Y型管行为实验结果显示，注射了dsRNA的蚜虫对EBF没有趋避行为。 2．利用RNAi技术证明OBP3和OBP7基因在豌豆蚜体内参与了对报警信息素EBF的识别。单独注射OBP3或OBP7的dsRNA，虽然基因表达量显著下降，但是豌豆蚜对EBF的趋避行为和EAG反应与对照组相比都没有显著性差异。同时注射OBP3和OBP7的dsRNA，处理组蚜虫对EBF丧失了趋避行为，相应的EAG反应显著减弱。 3．两个嗅觉受体基因参与豌豆蚜对报警信息素EBF的识别。单独注射OR5或OR20的dsRNA，基因表达量显著下降，而且豌豆蚜对EBF的趋避行为和EAG反应显著减弱。利用EAG玻璃电极遮盖豌豆蚜触角第五第六节的EAG实验表明，豌豆蚜触角感受EBF的部位主要在触角顶端两节。实时荧光定量PCR检测到这两条基因在豌豆蚜触角中高度表达。
[Abstract]:Insects rely on a sensitive olfactory system to sense the specific odour molecules in the environment, and then initiate corresponding behavioral responses, such as looking for food, finding spawning or reproductive sites, avoiding natural enemies, and so on. Aphids are important pests in agriculture and forestry. Aphids secrete an alarm pheromone when threatened by the outside world. The main component of this warning pheromone is Ean- 尾 -farneseneeEBFN, which can not only effectively prevent aphids from gathering and control the number of aphids. It also provides reliable clues for natural enemies to search for aphids. The molecular mechanism of aphids recognizing alarm pheromones can be used to screen and design more stable and non-volatile aphids warning pheromones at molecular level than EBF. All the odor binding proteins and odor receptor genes were identified from the genome of cotton aphids and pea aphids in our laboratory. In this paper, a method of RNAi interference in aphids was established. The molecular mechanism of aphids' recognition of alarm pheromones was preliminarily clarified by means of comparative genomics, RNAi and behavior determination techniques. The main results are as follows: 1. The alarm pheromone was recognized by the olfactory receptors of the pea aphids. The atypical odor receptor Orco gene was identified and cloned from the antennae of the pea aphid. The spatial and temporal expression profiles of the Orco gene were studied. The results showed that the Orco gene was mainly expressed in the antennae of the aphid. Orco gene dsRNAs were synthesized in vitro. The relative expression of Orco gene decreased by about 50% compared with the control at 72 h after injection. The results of antenna potential recording showed that the response of aphids injected with dsRNA to EBF was significantly decreased. Aphids injected with dsRNA did not avoid EBF. 2. RNAi technique was used to prove that OBP3 and OBP7 genes were involved in the recognition of alarm pheromone EBF in pea aphids. DsRNAs of OBP3 or OBP7 alone had no significant difference in EBF avoidance behavior and EAG response to EBF, although the gene expression level was significantly decreased. After dsRNAs of OBP3 and OBP7 were injected at the same time, the aphids in the treatment group lost the behavior of avoidance to EBF, and the corresponding EAG response was significantly weakened. 3. Two olfactory receptor genes were involved in the recognition of the alarm pheromone EBF in pea aphids. DsRNAs of OR5 or OR20 alone decreased gene expression, and the resistance to EBF and EAG response of aphids decreased significantly. The EAG experiment using EAG glass electrode to cover the fifth and sixth session of the antennae of the pea aphid showed that the part of the antennae of the apical pea aphid felt EBF mainly in the two segments of the top of the antennae. The two genes were highly expressed in the antennae of the pea aphid by real time fluorescence quantitative PCR.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S433

【参考文献】