Acta Entomologica Sinica ›› 2021, Vol. 64 ›› Issue (5): 627-644.doi: 10.16380/j.kcxb.2021.05.010

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Progress in the functional research of odorant receptors of agricultural insects

 YOU Yin-Wei1,*, ZHANG Long    

  1.  (1. Biotechnology Research Center, Shandong Academy of Agricultural Sciences, Jinan 250100, China; 2. College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China)
  • Online:2021-05-20 Published:2021-05-31

Abstract:  Insects mainly rely on the olfactory system to seek foods, find mates, control mating, select oviposition sites and avoid natural enemies. Olfactory system is crucial for insect reproduction and survival. Odorant receptor (OR) is one of the key components of the olfactory system in insects. ORs can be activated by semiochemicals and then trigger special behaviors. With the development of sequencing technique, genomes and transcriptomes of plenty of agricultural insects have been sequenced, and OR gene families are analyzed and acquired from the sequencing data. Heterologous expression system and CRISPR/Cas9 system are frequently used in the research of OR functions nowadays. Heterologous expression system combined with recording system can be used to express target ORs and screen ligands. CRISPR/Cas9 system can be used to knock out target OR genes from insect chromosome, and then their functions are studied by electrophysiological techniques and behavioral experiments. In this article we systematically summaried the odorantresponse spectra and functions of the ORs of 30 agricultural insect species in six orders, Lepidoptera, Orthoptera, Hemiptera, Diptera, Hymenoptera and Coleoptera, particularly in Lepidoptera. Sex pheromones of agricultural insects are usually produced by females and consist of blends of two or more components at certain ratios, including behavioral antagonists involved in interspecific reproductive isolation. So several sex pheromone receptors in one species will be used to sense these pheromonal messages and then regulate intra- and inter-specific sexual behaviors. Some ORs are mainly tuned to plant volatiles including floral scent compounds, which play roles in host plant selection and oviposition site selection. Aggregation pheromone receptors can be activated by aggregation pheromones triggering aggregation behavior. Alarm pheromone receptors can be activated by alarm pheromones eliciting repellent behavior. Studies of odorant-response spectra and functions of ORs of agricultural insects will lay solid foundations for developing sex attractants, food attractants, antifeedants and aggregation pheromones used in pest control. At last we suggested the main research directions in the future for the agricultural insect ORs, including: (1) developing new heterologous expression systems for ORs; (2) investigating the functions of sex pheromone receptors in females specifically tuned to male-emitted sex pheromone components; and (3) exploring the molecular mechanisms of OR-odorant specific interactions.

Key words: Agricultural insects, odorant receptor, sequencing technique, odorant-response spectrum, biological function