Transcriptome-Based Identification of Highly Similar Odorant-Binding Proteins among Neotropical Stink Bugs and Their Egg Parasitoid

Luciana R Farias,Priscila Grynberg,Débora P Paula,Sônia N Báo,Raul A Laumann,Miguel Borges,Maria Carolina Blassioli-Moraes,Pedro H C Schimmelpfeng,Marcos M C Costa,Roberto C Togawa,Natália F Martins

doi:10.1371/journal.pone.0132286

Luciana R Farias, Priscila Grynberg + Show 9 more

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https://doi.org/10.1371/journal.pone.0132286

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Abstract

Olfaction plays a fundamental role in insect survival through resource location and intra and interspecific communications. We used RNA-Seq to analyze transcriptomes for odorant-binding proteins (OBPs) from major stink bug pest species in Brazil, Euschistus heros, Chinavia ubica, and Dichelops melacanthus, and from their egg parasitoid, Telenomus podisi. We identified 23 OBPs in E. heros, 25 OBPs in C. ubica, 9 OBPs in D. melacanthus, and 7 OBPs in T. podisi. The deduced amino acid sequences of the full-length OBPs had low intraspecific similarity, but very high similarity between two pairs of OBPs from E. heros and C. ubica (76.4 and 84.0%) and between two pairs of OBPs from the parasitoid and its preferred host E. heros (82.4 and 88.5%), confirmed by a high similarity of their predicted tertiary structures. The similar pairs of OBPs from E. heros and C. ubica may suggest that they have derived from a common ancestor, and retain the same biological function to bind a ligand perceived or produced in both species. The T. podisi OBPs similar to E. heros were not orthologous to any known hymenopteran OBPs, and may have evolved independently and converged to the host OBPs, providing a possible basis for the host location of T. podisi using E. heros semiochemical cues.

Highlights

The phytophagous stink bugs, Euschistus heros (Fabricius, 1794), Chinavia ubica (Rolston, 1983) and Dichelops melacanthus (Dallas, 1851) (Hemiptera: Pentatomidae), are responsible for severe damage to important crops in the Neotropical region, mostly soybean in the reproductive stage [1,2,3,4]
The transcriptomes of E. heros, C. ubica and D. melacanthus stink bugs were similar to that of other hemipteran species and the transcriptome of T. podisi parasitoid was similar to other hymenopteran species
Transcriptome analyses enabled the mining of putative odorant binding proteins (OBPs), with a similar number identified from E. heros and C. ubica stink bugs, which was higher than from other Hemiptera in the Miridae, Aphididae and Delphacidae families

Summary

Introduction

The phytophagous stink bugs, Euschistus heros (Fabricius, 1794), Chinavia ubica (Rolston, 1983) and Dichelops melacanthus (Dallas, 1851) (Hemiptera: Pentatomidae), are responsible for severe damage to important crops in the Neotropical region, mostly soybean in the reproductive stage [1,2,3,4] They locate their host plants through constitutive plant volatiles [5], and signal within their own species through pheromones (e.g. sexual and alarm) [6,7]. OBPs have been classified into subfamilies based on the number of conserved Cys: classical OBPs (six), plus-C (more than six and a conserved proline, and according to Ji et al [44] with a C-terminal extension), minus-C (less than six), and OBP dimers (two complete OBP domains each with six conserved Cys) [37,41,43,45,46,47,48,49,50]

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