Fan Jia, Xue Wenxin, Duan Hongxia, Jiang Xin, Zhang Yong, Yu Wenjuan, Jiang Shanshan, Sun Jingrun, Chen Julian
State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
Department of Applied Chemistry, College of Science, China Agricultural University, Beijing 100193, China.
J Insect Physiol. 2017 Aug;101:151-160. doi: 10.1016/j.jinsphys.2017.07.014. Epub 2017 Aug 1.
(E)-β-farnesene (EBF) is the common active component of aphid alarm pheromone. Either or both of two orthologs of ordorant-binding proteins (OBPs), OBP3 and OBP7, recently reported in aphids, may be involved in EBF perception. The aim of this study was to investigate the respondence of the aphid Rhopalosiphum padi to its intraspecific alarm pheromone and which OBP is responsible for that response. We tested the olfactory response of the aphid R. padi to EBF and freshly crushed aphids. Then, we extracted the volatiles from crushed aphids using solid phase microextraction (SPME) for analysis with GC×GC-TOF/MS. We also cloned two OBPs cDNAs in R. padi (RpadOBP3 and RpadOBP7) and expressed them in competent Escherichia coli cells. Both recombinant proteins, RpadOBP3 and RpadOBP7, bound EBF well, with RpadOBP7 having specifically stronger affinity for EBF than for other volatiles. Based on the crystal structure of the OBPs with high identity, we performed homology modeling and analyzed the interactions between RpadOBPs and EBF. In conclusion, R. padi was repelled by both EBF and crushed aphids. EBF was identified as the only volatile that acted as the alarm pheromone. Our results indicated that OBP7 is a potential molecular target to control wheat aphids by disturbing their behaviors to the alarm pheromone.
（E）-β-法尼烯（EBF）是蚜虫报警信息素的常见活性成分。最近在蚜虫中报道的两种气味结合蛋白（OBP）直系同源物OBP3和OBP7中的一种或两种可能参与EBF的感知。本研究的目的是调查禾谷缢管蚜对其种内报警信息素的反应以及哪种OBP负责这种反应。我们测试了禾谷缢管蚜对EBF和新鲜碾碎蚜虫的嗅觉反应。然后，我们使用固相微萃取（SPME）从碾碎的蚜虫中提取挥发物，用于气相色谱-质谱联用仪（GC×GC-TOF/MS）分析。我们还克隆了禾谷缢管蚜中的两个OBP cDNA（RpadOBP3和RpadOBP7），并在感受态大肠杆菌细胞中表达它们。两种重组蛋白RpadOBP3和RpadOBP7都能很好地结合EBF，其中RpadOBP7对EBF的特异性亲和力比对其他挥发物更强。基于具有高度同一性的OBP晶体结构，我们进行了同源建模并分析了RpadOBP与EBF之间的相互作用。总之，禾谷缢管蚜对EBF和碾碎的蚜虫都有排斥反应。EBF被确定为唯一作为报警信息素的挥发物。我们的结果表明，OBP7是通过干扰小麦蚜虫对报警信息素的行为来控制小麦蚜虫的潜在分子靶点。
