麦长管蚜对驱避剂的嗅觉识别及其激活翅型分化机制

The peripheral nervous system of the insect with a variety of sensilla and reactors, are of two key functions of sensory identification and reactor response. The project team's previous study showed that aphid alarm pheromone [(E)-β-farnesene,EBF] and herbivore induced plant volatiles (HIPVs) [methyl salicylate, MeSA]，are two kinds of wheat aphid repellents and have the effect of activating wing differentiation, resulting in a significant increase in the proportion of winged aphids in the population, but the mechanism of olfactory nerve is unclear. In the proposal, based on the genomics of Sitobion avenae by third generation sequence technology, around afferent signal pathway (olfactory recognition) and efferent nerve pathway (stimulating wing differentiation signal). Researches will be conducted to annotate and functional identify the olfactory related genes, the signal transduction and regulation genes of winge morph differentiation in S. avenae. The aim is to uncover specific recognition and responsive gene families for EBF and MeSA. Then, in combination some known genes, for example OBP3/7/9, OR5/ORCO, and InOR1/InOR2 which are associated with EBF recognition of olfactory and wing morph differentiation, with comprehensive genomics, chemical ecology, and molecular biology techniques, a systematical study conducted on S. avenae's detection and response to repellents (EBF and MeSA). The results will lay a foundation for the molecular mechanism of the olfactory perception, phenotypic plasticity of wings in wheat aphid by repellents.

昆虫外周神经系统连接感觉器和反应器，分别具有识别外界信号和产生应答反应的功能。本项目组前期研究表明，蚜虫报警激素——(E)-β-法呢烯（EBF）和虫害诱导植物挥发物——水杨酸甲酯（MeSA）是蚜虫驱避剂，并具有刺激蚜虫翅分化，导致种群中有翅蚜比例上升的作用，但其嗅觉神经机制尚不清楚。本项目基于麦长管蚜基因组三代测序数据，围绕外周神经感觉器信号通路（嗅觉识别）和反应器信号转导（刺激翅分化信号），对麦长管蚜嗅觉关联基因和翅分化信号转导及调控基因进行注释和功能鉴定，发掘对EBF及MeSA特异识别及应答基因；结合已知与EBF识别嗅觉相关基因OBP3/7/9 、OR5/ORCO基因和逆境诱导翅分化有关受体InOR1/InOR2，综合基因组学、化学生态学、分子生物学技术手段，深入研究麦长管蚜识别和响应驱避剂EBF和MeSA的分子机制。为揭示驱避剂对麦长管蚜的驱散及有翅蚜增加的翅型可塑性分子机制奠定基础。

本项目以我国小麦重大害虫荻草谷网蚜为研究对象，针对报警信息素 (E)-β-法尼烯（EBF）既驱避蚜虫，又引发“类拥挤”效应，导致种群有翅蚜比例上升的现象，开展其外周嗅觉神经信号通路和翅分化反应器信号转导分子机制解析。.在项目资助下，组装荻草谷网蚜基因组图谱；获取了珍贵的蚜触角、头、足、翅、腹管、尾片空间转录组数据，分析蚜气味结合蛋白（OBP）表达模式；近一步分析EBF结合蛋白在成蚜期的表达模式；筛选参与翅型分化发育的蚜虫特有新基因ZX-5。主要结果如下：.1).组装首个荻草谷网蚜基因组（397.90Mb），并进一步装载到染色体水平（2n=18）。注释16006个编码基因。系统进化分析显示，荻草谷网蚜与豌豆蚜相对近缘，其分化大约发生在7.69-8.83亿年前；.2).OBP的组织表达特征分析揭示广泛的协作互作模式。例如，EBF结合蛋白OBP3在翅和腹管显著高表达，提示除参与EBF识别可能有其它生理功能，以及不限于化学信息物的配体结合谱；.3).EBF结合蛋白在成蚜期的表达特征分析揭示其协作模式。OBP9通过上调表达量来响应特定浓度的EBF诱导，而OBP7只在有翅型中出现诱导响应。无论有、无翅型的OBP3均不响应EBF诱导。以上说明OBP3和OBP9共同构筑蚜虫EBF识别的分子基础，而OBP7在有翅蚜更灵敏的BEF识别过程中发挥重要作用；.4).基于基因组和转录组联合分析，富集有翅蚜特异表达新基因数据，结合功能验证筛选并发现新基因ZX-5在有翅若蚜羽化过程中可保证翅的发育完全和充分伸展。.本项目结合化学生态学、分子生物学方法对蚜虫EBF识别和响应诱导的翅表型可塑性分子机制开展了研究。以上进展为全面解析EBF生物学功能，揭示驱避剂诱导蚜虫翅分化联动机制奠定理论基础。同时为充分挖掘EBF应用潜力，利用其实现驱避蚜虫、吸引天敌和调控有翅蚜发生、阻断虫源扩散的绿色控蚜技术提供理论支撑。