Li Hongwei, Wang Peng, Zhang Liwei, Xu Xiao, Cao Zewen, Zhang Long
Department of Entomology, China Agricultural University, Beijing, China.
Front Physiol. 2018 Jun 4;9:663. doi: 10.3389/fphys.2018.00663. eCollection 2018.
The main chemosensory organs of locusts consisted of the antennae and the mouthparts (maxillary and labial palps), which are suggested to perform different functions. However, very few are known about the differences of these two organs at molecular level. To understand the differences of locust antennae and palps in olfaction, the electrophysiological response and olfactory gene expression of these two organs were conducted. Our electrophysiological experiments with showed that the responses of mouthpart palps and antennae to odorants are quite different. Only a few odorants, such as (E,E)-2,4-hexadienal and (E,E)-2,4-heptadienal, elicited stronger electrophysiological responses of both maxillary and labial palps in comparison to the antennae. Additionally, we obtained 114 and 11 putative odorant receptor (OR) gene segments from the antennal and palp transcriptomes, respectively. Two novel odorant-binding proteins (OBPs; and ) and one novel OR () were identified for the first time. Out of the 16 OBP genes tested in RT-PCR and qPCR analyses, was highly expressed in the nymphal palps. , and were only detected in the antennae. The other 11 OBP genes were jointly expressed in both antennae and palps. The relative expression level of in male palps was much higher than that of female palps. Furthermore, for the 11 OR genes identified in palp transcriptome, the expression levels of , and in the palps were significantly higher than those in the antennae. The in palps was demonstrated to be involved in detection of hexanal and E-2-hexenal, as well as (E,E)-2,4-heptadienal. Our results provide information on the different olfactory roles of locust antennae and palps at the molecular level.
蝗虫的主要化学感受器官由触角和口器（下颚须和唇须）组成，它们被认为执行不同的功能。然而，在分子水平上，关于这两个器官的差异却知之甚少。为了解蝗虫触角和触须在嗅觉方面的差异，对这两个器官进行了电生理反应和嗅觉基因表达研究。我们的电生理实验表明，口器触须和触角对气味剂的反应截然不同。只有少数气味剂，如（E,E）-2,4-己二烯醛和（E,E）-2,4-庚二烯醛，与触角相比，能引起下颚须和唇须更强的电生理反应。此外，我们分别从触角和触须转录组中获得了114个和11个假定的气味受体（OR）基因片段。首次鉴定出两种新型气味结合蛋白（OBP； 和 ）和一种新型OR（ ）。在RT-PCR和qPCR分析中检测的16个OBP基因中， 在若虫触须中高表达。 、 和 仅在触角中检测到。其他11个OBP基因在触角和触须中共同表达。 在雄性触须中的相对表达水平远高于雌性触须。此外，对于在触须转录组中鉴定出的11个OR基因， 、 和 在触须中的表达水平显著高于触角。已证明触须中的 参与己醛、E-2-己烯醛以及（E,E）-2,4-庚二烯醛的检测。我们的结果在分子水平上提供了关于蝗虫触角和触须不同嗅觉作用的信息。
