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). A number of Orcoorthologs have been studied to date, although none has been identified in cereal aphids. It believes that the aphid's responses topheromone and plant volatiles at the molecular level offers a promising way to explain the ecological context of aphid-aphid and aphid-plant interactions. In turn, this approach will facilitate the design and implementation of sustainable aphid management strategy, namely the push-pull strategy.

Recently, researchers at State Key Laboratory of Plant Diseases and Insect Pests, Institute of Plant Protection of CAAS have published a research paper on Insect Biochemistry and Molecular Biology to obtain a deeper understanding of the physiological function of Orco in Sitobion avenae. In this study, an Orco gene ortholog was cloned from the grain aphid, S. 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 postnatal periods in untreated aphids, but no such induction was observed in the RNAi-treated aphids. The study concludes that SaveOrco is crucial for the aphid's response to pheromones and other volatiles, and is involved in wing differentiation triggered by EBF.

The study was financially supported by the China Postdoctoral Science Foundation (2012M510672), the National Natural Science Foundation of China (31371946, 31401740), The Agricultural Science and Technology Innovation Program (ASTIP), The National S &T Major Project (2014ZX0800201B), and Project of Modern Agro-Industry Technology Research System (CARS-3).