Discovery of behaviorally active semiochemicals in Aenasius bambawalei using a reverse chemical ecology approach

Abstract

BACKGROUND The invasive mealybug, Phenacoccus solenopsis, has caused serious damage to cotton crops throughout the world. Aenasius bambawalei is a dominant endoparasitoid of P. solenopsis. Exploration of behaviorally active semiochemicals may promote the efficacy of parasitoids used in biological control. Reverse chemical ecology, based on the physiological function of odorant‐binding proteins (OBPs), provides an effective approach to screen behaviorally active compounds to target insect pests. Determination of the binding mechanisms and specificity towards different odorants in A. bambawalei may facilitate the development of more‐efficient biological control strategies. RESULTS We characterized the expression profile and analyzed the binding affinity of OBP28 in A. bambawalei. AbamOBP28 showed high expression in the wings and antennae of both male and female A. bambawalei. A fluorescence competitive binding assay indicated that AbamOBP28 displayed strong binding affinity to most candidate ligands. Circular dichroism spectra demonstrated that 1‐octen‐3‐one, myrcene, dodecane, 2,4,4‐trimethyl‐2‐pentene, nonanal, and limonene elicited conformational changes in AbamOBP28. Electrophysiological and behavioral bioassays revealed that diethyl sebacate, 2,4,4‐trimethyl‐2‐pentene, and 1‐octen‐3‐one evoked significant electroantennography responses and functioned as attractants in A. bambawalei at specific concentrations. Furthermore, three‐dimensional structure modeling and molecular docking showed that hydrogen bonds were formed by Glu1 and Ser75 of AbamOBP28 with diethyl sebacate, respectively. CONCLUSION These results demonstrate that AbamOBP28 is involved in the chemoreception of A. bambawalei. The identified protein provides a potential target for efficient enemy utilization and pest control, and the overall results may help develop protocols for more effective screening of behaviorally active semiochemicals. © 2021 Society of Chemical Industry

Sublethal Exposure to Cadmium Induces Chemosensory Dysfunction in Fire Ants

“…The detailed procedures for protein function determination, including cDNA cloning, vector plasmid construction, recombinant protein expression and purification, and the binding affinity evaluation of SiOBPs, are respectively elaborated in Text S8, Text S9, and Text S10 based on previous studies. 27,37 Electrophysiological Responses in Cd-Contaminated S. invicta. Electroantennography (EAG) is an efficient technology to explore insect chemoreception mechanisms and screen the bioactive semiochemical components.…”

“…2,4,6-Trimethylpyridine had been found to have strong electrophysiological and behavioral activities with fire ant workers in our previous studies. , Ant workers from colonies without Cd exposure were used for RNA extraction. The detailed procedures for protein function determination, including cDNA cloning, vector plasmid construction, recombinant protein expression and purification, and the binding affinity evaluation of SiOBPs, are respectively elaborated in Text S8, Text S9, and Text S10 based on previous studies. , …”

Odorant‐binding protein 19 in Monochamus alternatus involved in the recognition of a volatile strongly emitted from ovipositing host pines

“…, 2017; Xu et al. , 2021). Moreover, knockdown of OBPs that play essential roles in detecting key chemical signals may lead to behavior disorder by inducing loss of function, which may contribute to pest management (Pelletier et al.…”

“…Due to the importance of OBPs in olfactory recognition, they can be used as targets to screen for active volatiles that have potential to regulate the behavior of insects, which is an important aspect of reverse chemical ecology (Leal et al, 2008;Zhu et al, 2017;Xu et al, 2021). Moreover, knockdown of OBPs that play essential roles in detecting key chemical signals may lead to behavior disorder by inducing loss of function, which may contribute to pest management (Pelletier et al, 2010;Zhang et al, 2017;Wang et al, 2021).…”

The Olfactory Chemosensation of Hematophagous Hemipteran Insects

“…In R. prolixus , one male-enriched OR (RproOR80) was functionally sensitized to 4-methylcyclohexanol, which turned out to be a strong repellent for kissing bugs by inducing a significant decrease in residence time to the host and a remarkable reduction in blood intake ( Franco et al, 2018 ). This reverse chemical ecology strategy has also been adopted for identifying compounds with biological significance for other blood-feeding insects ( Leal et al, 2008 ; Choo et al, 2018 ), agricultural insects ( Xu et al, 2021 ), and mammals ( Zhu et al, 2017 ). All these studies highlight the value of conducting further explorations of novel behaviorally active semiochemicals based on the reverse chemical ecology strategy for better controlling insect pests, such as bed bugs and kissing bugs and terminating the potential disease transmission.…”