Odor-Binding Protein 2 in Apis mellifera ligustica Plays Important Roles in the Response to Floral Volatiles Stimuli from Melon and Tomato Flowers

TL;DR

This study explores how a protein in honeybees helps them detect floral scents from melon and tomato flowers, influencing their foraging behavior.

Contribution

The study identifies AmelOBP2 as a key protein involved in honeybee recognition of melon and tomato floral volatiles.

Findings

AmelOBP2 mRNA is highly expressed in honeybee antennae, especially in melon greenhouses.

AmelOBP2 binds more strongly to melon floral volatiles than tomato ones.

Knocking down AmelOBP2 reduced honeybee electroantennogram responses to specific floral compounds.

Abstract

Honeybee olfaction can influence foraging behavior and affect crop pollination. Odor-binding proteins play a vital role in honeybee olfactory perception. A previous study based on the antennal transcriptome of Apis mellifera ligustica in melon and tomato greenhouses revealed that AmelOBP2 is highly expressed. Therefore, we aimed to further investigate the olfactory recognition mechanism of honeybees by detecting the expression levels and binding ability of AmelOBP2 to floral volatiles of melon and tomato flowers. The results show that AmelOBP2 mRNA was highly expressed in the antennae of honeybees, and its protein expression was highest in the antennae at 20 days of age and was higher in the melon greenhouse. The binding ability of AmelOBP2 to floral volatiles of melon was stronger than that of tomato. AmelOBP2 had a stronger binding ability with aldehydes in melon floral volatiles and with terpenes and benzenes in tomato floral volatiles. After feeding with siRNA, the electroantennogram response of honeybees to E-2-hexenal, E-2-octenal, and 1-nonanal decreased markedly, confirming the role of AmelOBP2 in the recognition of melon and tomato floral volatiles. These results elucidate the molecular mechanisms underlying honeybee flower-visiting behavior and provide a theoretical reference for regulating the behavior of honeybees using plant volatiles.

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