MOLECULAR CHARACTERIZATION, EXPRESSION PATTERNS, AND LIGAND‐BINDING PROPERTIES OF TWO ODORANT‐BINDING PROTEIN GENES FROM Orthaga achatina (BUTLER) (LEPIDOPTERA: PYRALIDAE)

Abstract

It is postulated that insect pheromone-binding proteins (PBPs) are involved in sex pheromone reception, while the general odorant-binding proteins (GOBPs) are involved in reception of the general odorants including plant volatiles. However, this functional specificity is not completely conclusive. In the present study, full-length sequences of two new OBP genes were molecularly identified as OachPBP1 and OachGOBP2 from Orthaga achatina, an important pest of the camphor tree Cinnamomum camphora. Quantification of transcript levels by qRT-PCR showed that the two genes highly expressed in antennae, with OachPBP1 male-biased and OachGOBP2 similar between sexes. These expression patterns are consistent with the generally proposed functions of PBPs and GOBPs. With the recombinant proteins obtained by a bacterial expression system, the binding specificity of these proteins was further investigated and compared using the competitive binding assay. OachPBP1 exhibited high binding affinities with all three putative sex pheromones and 10 pheromone analogs, supporting its role in pheromone reception. On the other hand, in addition to binding with some plant volatiles, OachGOBP2 surprisingly displayed similar or even higher binding affinities with the sex pheromones than OachPBP1. Therefore, we propose that OachGOBP2 might play roles in reception of sex pheromone. Additionally, plant volatiles farnesol and farnesene showed high binding with both OachGOBP2 and OachPBP1, suggesting that these volatile chemicals have regulatory functions in the behavior of O. achatina.

Differential Expression Patterns in Chemosensory and Non-Chemosensory Tissues of Putative Chemosensory Genes Identified by Transcriptome Analysis of Insect Pest the Purple Stem Borer Sesamia inferens (Walker)

“…In the early studies, the main method used to identify insect chemosensory genes was direct cloning [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], which normally involves designing degenerate primers, amplifying the fragment and obtaining the full length gene sequences by Rapid Amplification of cDNA Ends (RACE). This method is very time-consuming and inefficient, identifying only one gene each time.…”

Molecular Characterization, Expression Pattern, and Ligand-Binding Property of Three Odorant Binding Protein Genes from Dendrolimus tabulaeformis

“…The pheromone binding feature of GOBPs, as shown in our results, has been found in several insects. For example, pheromone binding properties were found in CsupGOBP2 of C. suppressalis (Gong et al 2009b), BmorGOBP2 of B. mori (He et al 2010; Zhou et al 2009), and AtraGOBP2 of A. stransitella (Liu et al 2012b). Based on the fact that the adults of many species of moths, such as D. tabulaeformis , do not need to locate food or other resources, but focus mainly on mating and oviposition, we propose that the functions of OBPs in these moths may be due to convergent evolution.…”

“…However, recent reports indicate that GOBPs can also bind pheromone components in some moth species. For example, GOBP2 of Orthaga achatina (Butler) showed high binding affinities for their sex pheromones (Liu et al 2012b). GOBP2 protein of Chilo suppressalis (Walker) had significant affinity to Z -11-hexadecenal ( Z 11–16:Ald), the main component of Ch.…”

The Lepidoptera Odorant Binding Protein gene family: Gene gain and loss within the GOBP/PBP complex of moths and butterflies

“…Similar ligand binding studies have also been performed on a limited number of OBPs from a broad range of insect Orders (e.g. Briand et al, 2001a,b;Wojtasek et al, 1998;Qiao et al, 2009;Jiang et al, 2009;Vandermoten et al, 2011;Gu et al, 2011a,b;Liu et al, 2012).…”