Different Binding Affinities of Three General Odorant-Binding Proteins inGrapholita funebrana(Treitscheke) (Lepidoptera: Tortricidae) to Sex Pheromones, Host Plant Volatiles, and Insecticides

Abstract

Insect general odorant-binding proteins (GOBPs) play irreplaceable roles in filtering, binding, and transporting host odorants to olfactory receptors. Grapholita funebrana (Treitscheke) (Lepidoptera: Tortricidae), an economically important pest of fruit crops, uses fruit volatiles as cues to locate host plants. However, the functions of GOBPs in G. funebrana are still unknown. Three GOBP genes, namely, GfunGOBP1, GfunGOBP2, and GfunGOBP3, were cloned, and their expression profiles in different tissues were detected by the method of real-time quantitative PCR (RT-qPCR). The binding properties of recombinant GfunGOBPs (rGfunGOBPs) to various ligands were investigated via fluorescence binding assays. The three GfunGOBPs were mainly expressed in the antennae of both male and female moths. All these three rGfunGOBPs could bind to sex pheromones, while having varying affinities toward these pheromones. The three rGfunGOBPs also displayed a wide range of ligand-binding spectrums with tested host odorants. The rGfunGOBP1, rGfunGOBP2, and rGfunGOBP3 bound to 34, 33, and 30 out of the 41 tested odorants, respectively. Three rGfunGOBPs had overlapping binding activities to β-myrcene, (-)-α-phellandrene, and ethyl isovalerate with the Ki less than 3.0 μM. The rGfunGOBP1 and rGfunGOBP3 could selectively bind to several insecticides, whereas rGfunGOBP2 could not. Three rGfunGOBPs had the dual functions of selectively binding to sex pheromones and host odorants. Moreover, the rGfunGOBP1 and rGfunGOBP3 can also serve as ‘signal proteins’ and bind to different insecticides. This study contributed to elucidating the potential molecular mechanism of the olfaction for G. funebrana, and thereby promotes the development of effective botanical attractants or pheromone synergists to control G. funebrana.

Two Antenna-Enriched Odorant Binding Proteins in Dioryctria abietella Tuned to General Odorants and Insecticides

“…In other insects, OBPs specifically or highly presented in the antennae have been indicated to be involved in host orientation and partner recognition [8,13,33]. In some case, sex-biased OBPs were capable of guiding female or male specific behaviors, such as CquiOBP1 in Culex quinquefasciatus [34], BodoOBP5 in Bradysia odoriphaga [35] and GfunGOBP3 in Grapholita funebrana [36] for female oviposition behaviors, as well as BodoOBP1 and BodoOBP2 in B. odoriphaga [37] and AlepOBP6 in A. lepigone [8] for male mating behaviors. Given the high and female-biased expression of two of the DabiOBPs in the principle olfactory organ, it was postulated that the two DabiOBPs were likely to sense odorants derived from host or non-host plants, with an emphasis on the putative roles in detecting oviposition-related compounds.…”

Identifying the Key Role of Plutella xylostella General Odorant Binding Protein 2 in Perceiving a Larval Attractant, (E,E)-2,6-Farnesol

“…12,14,15 Some recent evidence show that GOBP2 is directly involved in the perception of a sex pheromone component, (Z, E)-9, 11-tetradecadienyl acetate, in adult S. litura. 14 Additionally, insect GOBP2 can bind to many other compounds with different structures, including insecticides, 42,46,47 suggesting it may have multiple unknown physiological functions that warrant further investigation. Molecular simulation techniques were used to unravel the interaction mechanism between PxylGOBP2 and farnesol.…”

“…litura . Additionally, insect GOBP2 can bind to many other compounds with different structures, including insecticides, ,, suggesting it may have multiple unknown physiological functions that warrant further investigation.…”

Molecular and Functional Characterization of Three General Odorant-Binding Protein 2 Genes in Cydia pomonella (Lepidoptera: Tortricidae)

“…GOBPs can be further classified into two classes, GOBP1 and GOBP2. The main functions of GOBPs are the perception of host volatiles and the sex pheromone, which have been reported in various moths and butterflies, including Spodoptera frugiperda [14], Athetis lepigone [15], Conogethes pinicolalis [16], Hyphantria cunea [17], Grapholita funebrana [18], Orthaga achatina [19], Papilio xuthus [20], and so on. In addition, some GOBPs have binding abilities to insecticides, such as A. lepigone [21], Spodoptera litura [22], and P. xuthus [20].…”