Odorant-binding Protein 10 From Bradysia odoriphaga (Diptera: Sciaridae) Binds Volatile Host Plant Compounds

Abstract

Bradysia odoriphaga (Diptera: Sciaridae) is a major insect pest of seven plant families including 30 commercial crops in Asia. The long-term use of chemical pesticides leads to problems such as insect resistance, environmental issues, and food contamination. Against this background, a novel pest control method should be developed. In insects, odorant-binding proteins (OBPs) transport odor molecules, including pheromones and plant volatiles, to olfactory receptors. Here, we expressed and characterized the recombinant B. odoriphaga OBP BodoOBP10, observing that it could bind the sulfur-containing compounds diallyl disulfide and methyl allyl disulfide with Ki values of 8.01 μM and 7.00 μM, respectively. Homology modeling showed that the BodoOBP10 3D structure was similar to that of a typical OBP. Both diallyl disulfide and methyl allyl disulfide bound to the same site on BodoOBP10, mediated by interactions with six hydrophobic residues Met70, Ile75, Thr89, Met90, Leu93, and Leu94, and one aromatic residue, Phe143. Furthermore, silencing BodoOBP10 expression via RNAi significantly reduced the electroantennogram (EAG) response to diallyl disulfide and methyl allyl disulfide. These findings suggest that BodoOBP10 should be involved in the recognition and localization of host plants.

Molecular Characterization of Plant Volatile Compound Interactions with Cnaphalocrocis medinalis Odorant-Binding Proteins

“…For example, Bradysia odoriphaga shows strong EAG responses to the host plant volatiles methyl allyl disulfide and diallyl disulfide. Fluorescence competitive binding has shown that BodoOBP10 binds strongly to these two host plant volatiles, and RNAi has further indicated that BodoOBP10 is involved in host plant recognition and localization [ 46 , 47 ]. In Sitobion avenae , the OBP SaveOBP9 shows a strong binding force (Ki < 10 μM) with four wheat compounds: tetradecane, octanal, decanal, and hexadecane [ 48 ].…”

Roles of insect odorant binding proteins in communication and xenobiotic adaptation

“…A living host of a particular insect can vary greatly based on its life history and feeding guilds, ranging from plants to other animals or humans. Insect OBPs involved in the recognition of host semiochemicals are mainly expressed in the sensillum lymph of the antennae and assist in the adaptation of an insect to their hosts, which has been demonstrated across a diverse range of taxa (131)(132)(133). For example, it was found that An.…”

The Sequence Characteristics and Binding Properties of the Odorant-Binding Protein SvelOBP1 from Sympiezomias velatus (Coleoptera: Curculionidae) to Jujube Volatiles

“…Based on the number of conserved cysteine (Cys) residues, insect OBPs can be divided into five subfamilies: classic OBPs (six conserved cysteines), plus-C OBPs (eight conserved cysteines), minus-C OBPs (four conserved cysteines), dimer OBPs (twelve conserved cysteines) and atypical OBPs (nine to ten conserved cysteines) [16,17]. Since the first OBP was found in Antheraea polyphemus [18], more OBPs have been identified based on the transcriptome sequencing technique in recent years [19][20][21][22][23][24][25][26]. Collectively, these studies illustrated that OBPs, which were highly expressed in antennae as well as other body parts (e.g., legs, wings and larval maxilla), showed specific binding affinities with different host plant volatiles, and this phenomenon indicated that OBPs have the function of orientation and host selection at the molecular level.…”