title: Orco mediates olfactory behaviors and winged morph differentiation induced by alarm pheromone in the grain aphid, Sitobion avenae.
abstract: Olfaction is crucial for short distance host location and pheromone detection by insects. Complexes of olfactory receptors (ORs) are composed of odor-specific ORs and OR co-receptors (Orco). Orcos are widely co-expressed with odor-specific ORs and are conserved across insect taxa. A number of Orco orthologs have been studied to date, although none has been identified in cereal aphids. In this study, an Orco gene ortholog was cloned from the grain aphid, Sitobion avenae, and named "SaveOrco"; RNA interference (RNAi) reduced the expression of SaveOrco to 34.11% in aphids, resulting in weaker EAG (electroantennogram) responses to plant volatiles (Z-3-hexene-1-ol; methyl salicylate, MeSA) and aphid alarm pheromone (E-β-farnesene, EBF). Aphid wing differentiation induced by EBF was investigated in both RNAi treated and untreated aphids. EBF induced production of winged aphids in both pre-natal and post-natal periods in untreated aphids, but no such induction was observed in the RNAi-treated aphids. We conclude that SaveOrco is crucial for the aphid's response to pheromones and other volatiles, and is involved in wing differentiation triggered by EBF.
authors.affiliation: State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China.
authors.forename: Jia
authors.initials: J
authors.lastname: Fan
authors.affiliation: State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liege, Gembloux, B-5030, Belgium.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Francis
authors.affiliation: State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China.
authors.forename: Dengfa
authors.initials: D
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China.
authors.forename: Jingrun
authors.initials: J
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China. Electronic address: jlchen@ippcaas.cn.
authors.forename: Julian
authors.initials: J
authors.lastname: Chen
mesh_terms: D000818:Animals; D001042:Aphids / Q000254:growth & development / Q000502:physiology*; D057506:Arthropod Antennae / Q000502:physiology; D055724:Electrophysiological Phenomena; D000441:Hexanols / Q000494:pharmacology; D010675:Pheromones / Q000494:pharmacology; D034622:RNA Interference; D018035:Receptors, Odorant / Q000378:metabolism; D012459:Salicylates / Q000494:pharmacology; D012717:Sesquiterpenes / Q000494:pharmacology; D014921:Wings, Animal / Q000254:growth & development
chemical_list: D000441:Hexanols; D010675:Pheromones; D018035:Receptors, Odorant; D012459:Salicylates; D012717:Sesquiterpenes; C062671:beta-farnesene; C051918:3-hexen-1-ol; C033069:methyl salicylate
keywords: Aphid; Electroantennogram (EAG); Olfactometer; Olfactory coreceptor (Orco); RNAi; Winged morph differentiation