Institute of Plant Protection, Agricultural Research Organization, The Volcani Center, Rishon LeZion, Israel.
Institute of Agroecology and Plant Health, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel.
Sci Rep. 2017 Oct 12;7(1):13091. doi: 10.1038/s41598-017-13167-9.
Chemosensing is a primary sense in nature, however little is known about its mechanism in Chelicerata. As a model organism we used the mite Varroa destructor, a key parasite of honeybees. Here we describe a transcriptomic analysis of two physiological stages for the Varroa foreleg, the site of primary olfactory organ. The transcriptomic analysis revealed transcripts of chemosensory related genes belonging to several groups. These include Niemann-Pick disease protein, type C2 (NPC2), gustatory receptors (GRs), ionotropic receptors (IRs), sensory neuron membrane proteins (SNMPs) and odorant binding proteins (OBP). However, no insect odorant receptors (ORs) and odorant co-receptors (ORcos) were found. In addition, we identified a homolog of the most ancient IR co-receptor, IR25a, in Varroa as well as in other members of Acari. High expression of this transcript in the mite's forelegs, while not detectable in the other pairs of legs, suggests a function for this IR25a-like in Varroa chemosensing.
化感作用是自然界的一种主要感觉，但关于节肢动物门的化感作用机制却知之甚少。我们选择了螨类中的麦棉红蜘蛛（Varroa destructor）作为研究模式生物，这是一种对蜜蜂具有关键寄生作用的螨类。在此，我们对麦棉红蜘蛛前腿（主要嗅觉器官所在部位）的两个生理阶段进行了转录组分析。转录组分析揭示了属于几个基因家族的化感相关基因的转录本。这些基因包括 Niemann-Pick 疾病蛋白 C 型 2（NPC2）、味觉受体（GRs）、离子型受体（IRs）、感觉神经元膜蛋白（SNMPs）和气味结合蛋白（OBPs）。然而，没有发现昆虫气味受体（ORs）和气味共受体（ORcos）。此外，我们在麦棉红蜘蛛以及其他节肢动物成员中鉴定到了一种最古老的 IR 共受体 IR25a 的同源物。这种转录本在前腿中的高表达，而在其他腿中则无法检测到，这表明该 IR25a 样蛋白在麦棉红蜘蛛的化感作用中具有功能。
