Silencing the odorant coreceptor (Orco) disrupts sex pheromonal communication and feeding responses in Blattella germanica: toward an alternative target for controlling insect‐transmitted human diseases

• Published in: Pest management science Vol. 77; no. 4; pp. 1674 - 1682
• Main Authors: He, Peng, Ma, Yun‐Feng, Wang, Mei‐Mei, Wang, Hong, Dewer, Youssef, Abd El‐Ghany, Nesreen M, Chen, Guang‐Lei, Yang, Gui‐Qing, Zhang, Fan, He, Ming
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.04.2021; Wiley Subscription Services, Inc
• Subjects: Animal behavior; Animals; Antennae; Arthropod Antennae; Blattella germanica; Blattellidae - genetics; Chemical communication; Cockroaches; Communication; Disease transmission; Female; Food; Food processing; Food resources; food‐seeking behavior; Gene expression; Genes; Genetic screening; German cockroaches; Humans; Insect control; Insect Proteins - genetics; Insecta; Insects; Male; Maxillary palps; Odorant receptors; Odorants; olfaction; Olfactory system; Pests; Receptors; Receptors, Odorant - genetics; Ribonucleic acid; RNA; RNA-mediated interference; RNAi; Rural areas; Sex; Sex Attractants; Sex pheromone; transcriptomes; German cockroaches; RNAi; odorant receptors; sex pheromone; olfaction; transcriptomes; food-seeking behavior
• ISSN: 1526-498X; 1526-4998
• DOI: 10.1002/ps.6187

BACKGROUND The German cockroach, Blattella germanica, is one of the most severe pests of urban and rural areas. High‐throughput genetic screening approaches indicate that the olfactory system of this pest is extremely powerful because it has an extensive array of olfactory receptor genes compared with many other insect species. Several of these genes have been identified previously, but their functions have not yet been characterized. RESULTS This study describes the sequence of five transcriptomes of B. germanica adult male antennae, female antennae, maxillary palps, legs, and fifth‐instar nymph antennae to investigate expression patterns of odorant receptors (ORs). Approximately 90% of ORs were found to be the most highly expressed genes in adult or nymph antennae. Additionally, every OR requires an odorant co‐receptor (Orco) to become fully functional, and this was selected and successfully inhibited by injection of the corresponding double‐stranded (ds)RNA targeting the Orco. A strong RNA interference (RNAi) effect was observed in which > 75% of Orco messenger RNA (mRNA) was clearly suppressed after 72 h of treatment. Olfactory behavioral assays showed that Orco‐impaired B. germanica respond more slowly and show less attraction to one volatile sex pheromone and food resources compared with a control group. CONCLUSION The results show that Orco plays a pivotal role in both sex pheromone and food‐seeking olfactory processes, and provide an alternative genetic technique for controlling this urban pest species by olfactory disruption. © 2020 Society of Chemical Industry Conserved odorant co‐receptor (Orco) genes show a close relationship with insect olfaction. Knock‐down of the Orco in the German cockroach led to a reduction in smell ability and the insects were slower to seek sex pheromone and food resources. © 2020 Society of Chemical Industry