铃夜蛾雄性触角A、B和C型感器内气味受体的组合编码研究

Helicoverpa armigera and Helicoverpa assulta use (Z)-11-hexadecenal (Z11–16: Ald) and (Z)-9-hexadecenal (Z9–16: Ald) as the essential sex pheromone components but in opposite ratios, 97:3 and 7:93 respectively. The male moths evolved delicate chemoreception mechanisms to detect the opposite ratios of female sex pheromones. Our previous study indicated that the spike frequency and abundance of the olfactory sensory neurons (OSN) in the antennal trichoid sensilla determine the peripheral coding to the sex pheromones. One OSNs in the A type and another in the C type sensilla are tuned to the two components respectively. In the antennal lobe, α and β glomeruli show corresponding activities to two sex pheromone components. The responding profiles of the OSNs and glomeruli are mainly determined by the tuning spectrum of the pheromone receptors (PRs) expressed in the dendrite. However, we also found that some OSNs in the B type and C type sensilla responding to behavioral antagonists also play a crucial role in intra- and inter-specific communications. The goal of this project is further to examine the combinatorial coding mechanisms of the PRs in the A, B and C type sensilla of H. armigera and H. assulta. We will mainly focus on three aspects. First, we will characterize the function of OR11 located in a “silent OSN” in the A type sensilla and the receptors tuning to behavioral antagonists in the B and C type sensilla by heterologous expression systems. Secondly, we will determine the localization of PRs in each type of sensilla by in situ hybridization, and reveal the molecular basis of the subtypes in the C type sensilla. Finally, we will detect the responding activities of glomeruli in antennal lobes to agonists and antagonists by calcium imaging, and uncover the connections of PRs, OSNs, types of sensilla and glomeruli in the olfactory systems. We expect important discoveries on molecular mechanisms of pheromone coding in moths, and provide solid foundation for utilization of behavioral antagonists in pest control.

铃夜蛾属昆虫棉铃虫和烟青虫的性信息素组分均为Z11-16:Ald和Z9-16:Ald，比例分别为 97:3和7:93。前期我们揭示了二种昆虫对相反比例信息素的神经编码机制，在外周取决于雄性触角A型和C型感器内相关嗅觉神经元(OSN)的放电频率和丰度，在触角叶表现为α和β两个神经纤维球的活性，明确了调谐两种组分受体的特性，还发现B型和C型感器内调谐行为拮抗素的OSN也深刻影响同种的识别和种间隔离。本项目拟进一步剖析两种昆虫A、B、C型感器内气味受体的组合编码机制，内容包括：1)利用异源表达系统，研究A型感器中 “沉默”受体OR11的功能，鉴定B型和C型感器内调谐行为拮抗素的受体；2)利用原位杂交等技术，定位各型感器中OSN表达受体组合，揭示感器功能分化的分子基础；3)结合脑成像研究，建立气味受体-OSN-感器-神经纤维球间精确的联络图。预期在嗅觉分子编码和行为拮抗素应用方面取得突破。

铃夜蛾属昆虫棉铃虫和烟青虫的性信息素组分均为Z11-16:Ald和Z9-16:Ald，比例分别为97:3和7:93。前期我们揭示了二种昆虫对相反比例信息素的神经编码机制，在外周取决于雄性触角A型和C型感器内相关嗅觉神经元(OSN)的放电频率和丰度，在触角叶表现为两个神经纤维球的活性，明确了调谐两种组分的受体的特性，还发现B型和C型感器内调谐行为拮抗素的OSN也深刻影响同种的识别和种间的隔离。本项目进一步剖析两种昆虫A、B、C型感器内信息素受体的组合编码机制，在以下8个方面取得重要研究进展：(1) 利用果蝇空神经元表达系统鉴定了棉铃虫和烟青虫全套信息素受体的功能；(2) 分析了棉铃虫和烟青虫信息素受体的分子特征、表达模式、功能和演化； (3) 阐明了A、B、C型感器—嗅觉感受神经元—信息素受体—神经纤维球的联络图；(4) 揭示了A型感器内信息素结合蛋白与信息素受体OR13的协同感受性信息素主要组分Z11-16:Ald的模式；(5) 明确了棉铃虫与东方粘虫共享Z11-16:Ald作为性信息素的主要组分，并有类似的信息素受体和嗅觉神经通路; (6) 重新鉴定了入侵中国的草地贪夜蛾的性信息素；(7) 发现烟青虫通过产卵器上表达的气味受体HassOR31感受寄主植物气味物质； (8) 发现了菜粉蝶感受黑芥子苷的一个味觉受体。在国际重要期刊上发表标注项目的论文9篇，其中Insect Biochemistry and Molecular Biology 4篇，Entomologia Experimentalis et Applicata 1篇，eLife 1篇，PLoS Genetics 1篇，Insect Science 1篇，昆虫学报1篇。这些研究成果为利用信息化合物防治鳞翅目农业害虫提供了坚实的基础。