Identification and functional characterization of odorant-binding proteins 69a and 76a of Drosophila suzukii

Haixia Zhan; Du Li; Youssef Dewer; Changying Niu; Fengqi Li; Chen Luo

doi:10.1016/j.heliyon.2021.e06427

Identification and functional characterization of odorant-binding proteins 69a and 76a of Drosophila suzukii

Heliyon. 2021 Mar 10;7(3):e06427. doi: 10.1016/j.heliyon.2021.e06427. eCollection 2021 Mar.

Authors

Haixia Zhan¹, Du Li^{1

2}, Youssef Dewer³, Changying Niu², Fengqi Li¹, Chen Luo¹

Affiliations

¹ Beijing Key Laboratory of Environment Friendly Management on Fruit Diseases and Pests in North China, Institute of Plant and Environment Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China.
² Hubei Key Laboratory of Insect Resource Application and Sustainable Pest Control, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan, China.
³ Bioassay Research Department, Central Agricultural Pesticide Laboratory, Agricultural Research Center, Dokki, Giza, Egypt.

Abstract

The fruit fly Drosophila suzukii is a fruit crop pest that causes a severe economic threat to soft summer fruit worldwide. The male sex pheromone, cis-vaccenyl acetate (cVA) has multiple functions in intra-species communication in Drosophila melanogaster, which is required in male to suppress male-male courtship. D. suzukii males do not produce cVA; however, the odorant receptor for cVA (Or67d) is still functional. The lack of cVA in D. suzukii casts the question of whether this pheromone might have been replaced by another compound similar to cVA that disrupts mating in D. suzukii. In order to address this question, we cloned two D. suzukii adult antenna-specific odorant-binding proteins (OBPs) DsOBP69a and DsOBP76a and aligned with their D. melanogaster orthologues. Moreover, we examined the binding properties of the newly identified recombinant proteins against 26 potential ligands including cVA, using the fluorescence-based ligand binding assay. The alignment showed that DsOBP69a and DsOBP76a, have six conserved cysteines and belong to the classic OBP family. Furthermore, our results revealed that cVA did not bind to DsOBP69a or DsOBP76a proteins. Interestingly, the floral odorant β-ionone and the bitter substance berberine chloride and coumarin displayed high binding ability. It is also worth noting that DsOBP69a and DsOBP76a have different affinities to (Z)-7-Tricosene that may reflect different functional roles. These findings suggest that DsOBP69a and DsOBP76a are potentially involved in olfaction and gustation of D. suzukii.

Keywords: (Z)-7-tricosene; Berberine; Competitive binding; Drosophila suzukii; Odorant-binding proteins; cis-vaccenyl acetate (cVA); β-ionone.