Chemosensory proteins used as target for screening behaviourally active compounds in the rice pest Cnaphalocrocis medinalis (Lepidoptera: Pyralidae)

Abstract

Reverse chemical ecology based on insect functional odorant binding proteins has been extensively studied to screen behaviourally active compounds, whereas chemosensory proteins (CSPs), which are reportedly involved in olfactory chemical reception and could serve as molecular targets remain unclear. In the present study, two behaviourally active compounds for Cnaphalocrocis medinalis, a serious pest of rice in Asia, were successfully screened via an antenna-biased CSP, CmedCSP33. Fluorescence competitive binding assays showed that CmedCSP33 could bind to seven out of 32 rice volatiles. Fluorescence quenching experiments revealed that CmedCSP33 forms a stable complex with nerolidol and β-ionone, and circular dichroism (CD) spectra demonstrated that these two compounds cause conformational changes in CmedCSP33. Furthermore, H-tube olfactometer bioassays showed that C. medinalis displayed prominent attractant responses to nerolidol and prominent repellent responses to β-ionone. Additionally, binding assays and CD spectra at different pH values implied that extensive conformational changes may be a general feature of CSPs for triggering the subsequent chemical transduction. Overall, our findings provide evidence for the involvement of CSPs in olfactory perception, and a protocol for effectively screening behaviourally active compounds.

Comparative genomic and transcriptomic analyses of chemosensory genes in the citrus fruit fly Bactrocera (Tetradacus) minax

“…Moreover, the expression patterns at three different developmental stages (larva, pupa and adult) were compared between B. dorsalis and B. minax. 25,37,33,35,30,29,34 OBP genes were identified in B. minax, B. dorsalis, B. cucurbitae, B. latifrons, B. oleae, R. zephyria, and C. capitata, respectively ( Table 1). 37 of 52 OBP sequences in D. melanogaster showed high homology to those in the seven selected tephritid species (Table 1).…”

Expression Profiles and Binding Properties of the Chemosensory Protein PxylCSP11 from the Diamondback Moth, Plutella xylostella (Lepidoptera: Plutellidae)

“…M. alternatus MaltCSP5 is mainly expressed in male and female antennae, and the protein has a high binding affinity to most pine volatiles ( Ali et al 2019 ). An antenna-enriched Cmed CSP33 protein in Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae) exhibites strong binding abilities to seven compounds of rice volatiles ( Duan et al 2019 ). Based on the above-mentioned study, the antennae-predominant Pxyl CSP11 may be responsible for binding host volatiles in olfactory recognition.…”

Deorphanization of an odorant receptor revealed new bioactive components for green mirid bug Apolygus lucorum (Hemiptera: Miridae)

“…Reverse chemical ecology approach, a new concept in the field of insect chemical ecology and similar to ‘receptor‐based drug discovery’, was firstly proposed by Professor Walter S. Leal in 2005 and recently is gaining more attention for the management of agricultural and medical pests . This method has been developed based on understanding the molecular basis of the insect's olfactory system and binding ability of two major types of olfactory proteins‐OBPs and ORs‐ to behaviorally active compounds . In comparison with conventional chemical ecology, reverse chemical ecology strategy is a quick and cost‐effective approach for screening of potential semiochemicals with putative behavioral effects which could be used as attractants or repellents.…”

“…34,35 This method has been developed based on understanding the molecular basis of the insect's olfactory system and binding ability of two major types of olfactory proteins-OBPs and ORs-to behaviorally active compounds. 8,36 In comparison with conventional chemical ecology, reverse chemical ecology strategy is a quick and cost-effective approach for screening of potential semiochemicals with putative behavioral effects which could be used as attractants or repellents. Among a large number of ORs expressed in the antennae of A. lucorum, a few have been functionally characterized and their ligands have been identified.…”