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BMC Biol

Title:		Mutagenesis of the odorant receptor co-receptor (Orco) reveals severe olfactory defects in the crop pest moth Helicoverpa armigera
Author(s):		Fan XB; Mo BT; Li GC; Huang LQ; Guo H; Gong XL; Wang CZ;
Address:		"State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing, 100101, People's Republic of China. CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, People's Republic of China. State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing, 100101, People's Republic of China. czwang@ioz.ac.cn. CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, People's Republic of China. czwang@ioz.ac.cn"
Journal Title:		BMC Biol
Year:		2022
Volume:		20220930
Issue:		1
Page Number:		214 -
DOI:		10.1186/s12915-022-01411-2
ISSN/ISBN:		1741-7007 (Electronic) 1741-7007 (Linking)
Abstract:		"BACKGROUND: Odorant receptors (ORs) as odorant-gated ion channels play a crucial role in insect olfaction. They are formed by a heteromultimeric complex of the odorant receptor co-receptor (Orco) and a ligand-selective Or. Other types of olfactory receptor proteins, such as ionotropic receptors (IRs) and some gustatory receptors (GRs), are also involved in the olfactory system of insects. Orco as an obligatory subunit of ORs is highly conserved, providing an opportunity to systematically evaluate OR-dependent olfactory responses. RESULTS: Herein, we successfully established a homozygous mutant (Orco(-/-)) of Helicoverpa armigera, a notorious crop pest, using the CRISPR/Cas9 gene editing technique. We then compared the olfactory response characteristics of wild type (WT) and Orco(-/-) adults and larvae. Orco(-/-) males were infertile, while Orco(-/-) females were fertile. The lifespan of Orco(-/-) females was longer than that of WT females. The expressions of most Ors, Irs, and other olfaction-related genes in adult antennae of Orco(-/-) moths were not obviously affected, but some of them were up- or down-regulated. In addition, there was no change in the neuroanatomical phenotype of Orco(-/-) moths at the level of the antennal lobe (including the macroglomerular complex region of the male). Using EAG and SSR techniques, we discovered that electrophysiological responses of Orco(-/-) moths to sex pheromone components and many host plant odorants were absent. The upwind flight behaviors toward sex pheromones of Orco(-/-) males were severely reduced in a wind tunnel experiment. The oviposition selectivity of Orco(-/-) females to the host plant (green pepper) has completely disappeared, and the chemotaxis toward green pepper was also lost in Orco(-/-) larvae. CONCLUSIONS: Our study indicates that OR-mediated olfaction is essential for pheromone communication, oviposition selection, and larval chemotaxis of H. armigera, suggesting a strategy in which mate searching and host-seeking behaviors of moth pests could be disrupted by inhibiting or silencing Orco expression"
Keywords:		"Animals Female Male Electrolytes Insect Proteins/metabolism Ion Channels Larva/genetics/metabolism Ligands *Moths/genetics Mutagenesis Pheromones *Receptors, Odorant/metabolism *Sex Attractants Smell CRISPR/Cas9 Chemotaxis Eag Helicoverpa armigera Odorant;"
Notes:		"MedlineFan, Xiao-Bin Mo, Bao-Tong Li, Guo-Cheng Huang, Ling-Qiao Guo, Hao Gong, Xin-Lin Wang, Chen-Zhu eng Research Support, Non-U.S. Gov't England 2022/09/30 BMC Biol. 2022 Sep 30; 20(1):214. doi: 10.1186/s12915-022-01411-2"