BdorCSP2 Is Important for Antifeed and Oviposition-Deterring Activities Induced by Rhodojaponin-III against Bactrocera dorsalis

Xin Yi,Xiaolin Dong,Meiying Hu,Peidan Wang,Haiming Zhao,Guohua Zhong,Elena Papaleo

doi:10.1371/journal.pone.0077295

Abstract

Rhodojaponin-III is a nonvolatile botanical grayanoid diterpene compound, which has antifeedant and oviposition deterrence effects against many kinds of insects. However, the molecular mechanism of the chemoreception process remains unknown. In this study, the important role of BdorCSP2 in the recognition of Rhodojaponin-III was identified. The full length cDNA encoding BdorCSP2 was cloned from legs of Bactrocera dorsalis. The results of expression pattern revealed that BdorCSP2 was abundantly expressed in the legs of adult B. dorsalis. Moreover, the expression of BdorCSP2 could be up-regulated by Rhodojaponin-III. In order to gain comprehensive understanding of the recognition process, the binding affinity between BdorCSP2 and Rhodojaponin-III was measured by fluorescence binding assay. Silencing the expression of BdorCSP2 through the ingestion of dsRNA could weaken the effect of oviposition deterrence and antifeedant of Rhodojaponin-III. These results suggested that BdorCSP2 of B. dorsalis could be involved in chemoreception of Rhodojaponin-III and played a critical role in antifeedant and oviposition behaviors induced by Rhodojaponin-III.

Highlights

Insects use chemical signals to locate and access habitat, food, partners, and sites for oviposition [1]
Multiple sequences alignment revealed that BdorCSP2 shared relatively high sequence identity with other members of the chemosensory proteins (CSPs) family isolated from contact sensilla (45%-65%) (Figure 1)
The results suggested that BdorCSP2 played an important role in antifeeding and oviposition deterrence activities induced by Rhodojaponin-III against B. dorsalis

Summary

Introduction

Insects use chemical signals to locate and access habitat, food, partners, and sites for oviposition [1]. The compounds which have effects of antifeedant and oviposition deterrence are parts of these defensive chemicals. Researchers are devoted to extract the novel botanical compounds that dually had both antifeeding and oviposition deterring activities to mediate insect behaviors [4,5,6]. Rhodojaponin-III, a diterpene compound isolated from the flowers of Rhododendron molle G, has been reported to have intense antifeedant activities against many kinds of agricultural pests [7]. Unlike other volatile chemicals, Rhodojaponin-III is a nonvolatile compound that could inhibit oviposition activities [7,8,9]. With its intense oviposition deterrence and antifeedant activities, Rhodojaponin-III could be an efficient candidate for sustainable pest management [11]. Little is known about the detailed chemoreception mechanism of Rhodojaponin-III as an antifeedant and oviposition deterrent to influence insect behaviors

Methods

Results

Conclusion