Host plant recognition by two odorant‐binding proteins in Rhynchophorus ferrugineus (Coleoptera: Curculionidae)

Abstract

BACKGROUNDRhynchophorus ferrugineus, the red palm weevil (RPW), is a key pest that attacks many economically important palm species and that has evolved a sensitive and specific olfactory system to seek palm hosts. Odorant‐binding proteins (OBPs) not only play crucial roles in its olfactory perception process but are also important molecular targets for the development of new approaches for pest management.RESULTSAnalysis of the tissue expression profiles of RferOBP8 and RferOBP11 revealed that these two Rhynchophorus ferrugineus odorant binding proteins (RferOBPs) exhibited high expression in the antennae and showed sexual dimorphism. We analyzed the volatiles of seven host plants by gas chromatography–mass spectrometry and screened 13 potential ligands by molecular docking. The binding affinity of two recombinant OBPs to aggregation pheromones and 13 palm odorants was tested by fluorescence competitive binding assays. The results revealed that eight tested palm volatiles and ferrugineol have high binding affinities with RferOBP8 or RferOBP11. Behavioral trials showed that these eight odor compounds could elicit an attraction response in adult RPW. RNA interference analysis indicated that the reduction in the expression levels of the two RferOBPs led to a decrease in behavioral responses to these volatiles.CONCLUSIONThese results suggest that RferOBP8 and RferOBP11 are involved in mediating the responses of RPW to palm volatiles and to aggregation pheromones and may play important roles in RPW host‐seeking. This study also provides a theoretical foundation for the promising application of novel molecular targets in the development of new behavioral interference strategies for RPW management in the future. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Binding Properties of Odorant Binding Protein 37 in Plagiodera versicolora to Host Volatile, o-Cymene

“…In R. ferrugineus, silencing RferOBP8 and RferOBP11 reduced preference for eight plant volatiles by Y-tube-choice behavioral assay. 33 In D. helophoroides, RNAi-mediated of DhelOBP4 lost the trend to γterpinene and p-cymene in Y-tube olfactometer bioassays. 46 Silencing HparOBP3 by the injection of dsRNA, the antennal electrophysiological responses and preference to compounds significantly reduced.…”

“…In R. ferrugineus, silencing RferOBP8 and RferOBP11 reduced preference for eight plant volatiles by Y-tube-choice behavioral assay . In D.…”

“…For example, RferOBP8 is located mostly in Rhynchophorus ferrugineus antennae and could bind with palm plant volatiles. 33 HoblOBP9 in Holotrichia oblita had high expression in female antennae and could bind to plantderived volatile (E)-2-hexenol. 34 Plagiodera versicolora (Laicharting) (Coleoptera: Chrysomelidae) that is a specialist herbivore on salicaceous plants.…”

“…OBPs are distributed in the chemosensory organs and involved in insect olfactory detection. For example, RferOBP8 is located mostly in Rhynchophorus ferrugineus antennae and could bind with palm plant volatiles . HoblOBP9 in Holotrichia oblita had high expression in female antennae and could bind to plant-derived volatile ( E )-2-hexenol …”

Odorant binding protein 18 increases the pathogen resistance of the imported willow leaf beetle, Plagiodera versicolora

“…This indicating that PverOBP18 may play an important role in various biologic processes during the life stage of P. versicolora. Usually, the majority of OBP genes are found to be expressed in chemosensory organs of insectile adults, including the antennae, maxillary palp and proboscis, such as P. versicolora ( Liu et al., 2021 ), Tribolium castaneum ( Dippel et al., 2014 ) and Rhynchophorus ferrugineus ( Huang et al., 2023 ). Previous study had found that PverOBP18 was mainly expressed in the antennae of adult P. versicolora when compared to other tissues, indicating the similar chemoreception function in P. versicolora ( Liu et al., 2021 ).…”