Identification and Functional Analysis of SlitOBP11 From Spodoptera litura.

Jiaojiao Luo,Lin He,Jie Liu,Zan Zhang,Kun Li,Dongzhen Li,Xiao Sun

doi:10.3389/fphys.2021.619816

Abstract

Odorant binding proteins (OBPs) play a key role in the olfactory recognition of insects, whose functions have been extensively studied in adult insects but rarely in larvae. In this study, one OBP (SlitOBP11) with high expression in larval antenna but low expression in adult antenna of Spodoptera litura was screened by RNA-seq and verified by quantitative real-time PCR. Furthermore, the function of SlitOBP11 was explored by analysis of the expression patterns and prokaryotic expression of proteins as well as assays of competitive binding. Competitive binding assay demonstrated that SlitOBP11 had high binding affinity to all four female sex pheromone components, but exhibited almost no binding affinity to plant volatiles except for a low affinity to Phenylacetaldehyde and Phenethyl acetate. Homology modeling and molecular docking implied that the shape of these four sex pheromones were linear, which were appropriate for the binding channel of SlitOBP11 and the amino acid residue Asn99 of SlitOBP11 might play an important role in binding. Taken together, our results indicate that SlitOBP11 may be involved in the perception of female sex pheromones by S. litura larvae, and OBPs in the larvae of S. litura play an important role in the olfactory perception process.

Highlights

Perception of chemical signals from the environment by olfaction is essential for the life of insects, and plays important roles in their host identification, search for mates and choice of oviposition sites (Brito et al, 2016)
pheromone binding proteins (PBPs) are known to have high expression in the antenna of male and participate in the recognition of sex pheromones (Vogt and Riddiford, 1981; Maida et al, 2005; Wen et al, 2019), while general odorant binding proteins (GOBPs) are believed to be involved in the recognition of general odorants such as plant volatiles as well as aggregation, alarm and trace pheromones
According to the Signal P 5.0 server, 23 amino acids were predicted as the signal peptide at the hydrophobic N-terminus

Summary

Introduction

Perception of chemical signals from the environment by olfaction is essential for the life of insects, and plays important roles in their host identification, search for mates and choice of oviposition sites (Brito et al, 2016). According to the sequence characteristics and homology, the OBP family in Lepidopteran insects can be subdivided into pheromone binding proteins (PBPs), antennal binding proteins (ABPx; Li et al, 2016), and general odorant binding proteins (GOBPs; Krieger et al, 1996). PBPs are known to have high expression in the antenna of male and participate in the recognition of sex pheromones (Vogt and Riddiford, 1981; Maida et al, 2005; Wen et al, 2019), while GOBPs are believed to be involved in the recognition of general odorants such as plant volatiles as well as aggregation, alarm and trace pheromones. It can be speculated that PBPs are the main OBPs for the perception of pheromones, some other common OBPs may be involved in pheromone perception

Methods

Results

Conclusion