Binding Properties of Odorant-Binding Protein 4 of Tirathaba rufivena to Areca catechu Volatiles.

Xiang Zhou,Zheng Wang,Minghui Liu,Guangchao Cui,Jixing Guo,Shumei Yang,Zimeng Du,Yunlong Qian

doi:10.3390/plants11020167

Abstract

Odorant-binding proteins (OBPs) play a key role in the olfactory system and are essential for mating and oviposition host selection. Tirathaba rufivena, a serious lepidopterous insect pest of the palm area in recent years, has threatened cultivations of Areca catechu in Hainan. Female-biased odorant-binding protein 4 of T. rufivena (TrufOBP4) expression was hypothesized to participate in the process of oviposition host recognition and localization. In this study, we cloned and analyzed the cDNA sequence of TrufOBP4. The predicted mature protein TrufOBP4 is a small, soluble, secretory protein and belongs to a classic OBP subfamily. Fluorescence binding assay results showed that TrufOBP4 had high binding abilities with the host plant volatiles, octyl methoxycinnamate, dibutyl phthalate, myristic acid and palmitic acid. These four components tend to dock in the same binding pocket based on the molecular docking result. The interactions and contributions of key amino acid residues were also characterized. This research provides evidence that TrufOBP4 might participate in the chemoreception of volatile compounds from inflorescences of A. catechu and can contribute to the integrated management of T. rufivena.

Highlights

The olfactory system of insects plays an important role in behaviors such as host seeking, mating, and oviposition [1]
Three pairs of disulfide bridges were formed by six conserved cysteines, which demonstrated that TrufOBP4 could belong to classic Odorant binding proteins (OBPs) subfamilies
TrufOBP4 was clustered with GmelOBP7 in the phylogenetic tree, which was consistent with the highest sequence similarity between them

Summary

Introduction

The olfactory system of insects plays an important role in behaviors such as host seeking, mating, and oviposition [1]. Insects can acquire information from chemical odorants in the external environment and respond [2]. The process of odor molecular recognition in insects is a very complex chain reaction [3,4,5]. The water-soluble carriers are required to transport the lipophilic odorant molecule to receptive membranes. OBPs are small and water-soluble proteins, and a typical OBP contains six conserved cysteine residues [8]. OBPs with more or less than six conserved cysteines have been identified and designated Plus-C OBPs and Minus-C OBPs, respectively [1,11]

Methods

Findings

Discussion

Conclusion