Discrimination of Oviposition Deterrent Volatile β-Ionone by Odorant-Binding Proteins 1 and 4 in the Whitefly Bemisia tabaci.

Li Li,Qu Qu,Yang Yang,Tian Tian,Luo Luo,Dewer Dewer

doi:10.3390/biom9100563

Abstract

The whitefly, Bemisia tabaci, is an important invasive economic pest of agricultural crops worldwide. β-ionone has a significant oviposition repellent effect against B. tabaci, but the olfactory molecular mechanism of this insect for recognizing β-ionone is unclear. To clarify the binding properties of odorant-binding proteins (OBPs) with β-ionone, we performed gene cloning, evolution analysis, bacterial expression, fluorescence competitive binding assay, and molecular docking to study the binding function of OBP1 and OBP4 on β-ionone. The results showed that after the OBP1 and OBP4 proteins were recombined, the compound β-ionone exhibited a reduction in the fluorescence binding affinity to <50%, with a dissociation constant of 5.15 and 3.62 μM for OBP1 and OBP4, respectively. Our data indicate that β-ionone has high affinity for OBP1 and OBP4, which play a crucial role in the identification of oviposition sites in B. tabaci. The findings of this study suggest that whiteflies employ β-ionone compound in the selection of the suitable egg-laying sites on host plants during the oviposition behavior.

Highlights

Insects have many chemosensory organs, including antennae and other parts of the body, that play a key role in communication, such as in host-plant recognition
OBP4 gene sequences of B. tabaci were obtained, which were consistent with the odorant-binding proteins (OBPs) sequences in our previous reports
Sequence alignment and phylogenetic tree construction of B. tabaci OBP1, OBP4, and the OBPs of other insects show that Q-type B. tabaci OBP1 is closely related to B-type B. tabaci OBP1

Summary

Introduction

Insects have many chemosensory organs, including antennae and other parts of the body, that play a key role in communication, such as in host-plant recognition. These chemosensory organs enable insects to successfully complete a series of important functions such as foraging, mating, oviposition, and avoidance. These behaviors contribute to insect survival in a complex environment [1,2]. OBPs are the most extensively studied chemosensory proteins. The first OBP was discovered in the 1980s in the male moth antenna of Antheraea polyphemus [3], which subsequently prompted entomologists to study OBP function

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Conclusion