Identification, Expression Patterns, and Functional Characterization of Chemosensory Proteins in Dendroctonus armandi (Coleoptera: Curculionidae: Scolytinae).

Zhumei Li,Honglong Chu,Hui Chen,Yaya Sun,Lulu Dai,Danyang Fu

doi:10.3389/fphys.2018.00291

Abstract

The Chinese white pine beetle, Dendroctonus armandi Tsai and Li (Coleoptera: Curculionidae: Scolytinae), is a serious pest of coniferous forests in China. Thus, there is considerable interest in developing eco-friendly pest-control methods, with the use of semiochemicals as a distinct possibility. Olfaction is extremely important for fitness of D. armandi because it is the primary mechanism through which the insect locates hosts and mates. Thus, here we characterized nine full-length genes encoding chemosensory proteins (CSPs) from D. armandi. The genes were ubiquitously and multiply expressed across different developmental stages and adult tissues, indicating various roles in developmental metamorphosis, olfaction, and gustation. Ligand-binding assays implied that DarmCSP2 may be the carrier of D. armandi pheromones and various plant host volatiles. These volatiles were identified through RNA interference of DarmCSP2 as: (+)-α-pinene, (+)-β-pinene, (−)-β-pinene, (+)-camphene, (+)-3-carene, and myrcene. The systematic chemosensory functional analysis of DarmCSP2 in this study clarified the molecular mechanisms underlying D. armandi olfaction and provided a theoretical foundation for eco-friendly pest control.

Highlights

Chemoreception is an indispensable biological process for many insect species (Sánchez-Gracia et al, 2009), playing a vital role in detecting the specific semiochemicals emitted by host plants or conspecifics (Yoshizawa et al, 2011)
DarmCSPs were classical chemosensory proteins (CSPs) genes based on a variety of hallmarks (Vieira and Rozas, 2011)
Previous reports have indicated that D. ponderosae, I. typographus, and D. valens CSP genes are orthologous (Andersson et al, 2013; Gu et al, 2015)

Summary

Introduction

Chemoreception (olfaction and gustation) is an indispensable biological process for many insect species (Sánchez-Gracia et al, 2009), playing a vital role in detecting the specific semiochemicals emitted by host plants or conspecifics (Yoshizawa et al, 2011). The special tertiary structure of CSPs with hydrophilic surface and hydrophobic cavity allow them to distinguish, capture, and bind hydrophobic chemicals from external environments to ORs or GRs (Pelosi et al, 2005, 2017; Gong et al, 2007; Sánchez-Gracia et al, 2009; Liu et al, 2012; Leal, 2013) Given their critical functions, chemosensory proteins are widespread and have been isolated from multiple insect orders (McKenna et al, 1994; Angeli et al, 1999; Robertson et al, 1999; Marchese et al, 2000; Forêt et al, 2007; Andersson et al, 2013; Li et al, 2013; Yang et al, 2014; He et al, 2017). These sophisticated expression profiles and binding ability suggest that the role of CSPs is complex, spanning from chemoreception to other functions in development, vision, nutrition, reproduction, and regeneration (Nomura et al, 1992; Briand et al, 2002; Wanner et al, 2005; Li et al, 2015; Zhu et al, 2016; Pelosi et al, 2017)

Methods

Results

Conclusion