RESUMEN
The identification of odorant-binding proteins (OBPs) involved in host location by Oides leucomelaena (O. leucomelaena Weise, 1922, Coleoptera, Galerucinae) is significant for its biological control. Tools in the NCBI database were used to compare and analyze the transcriptome sequences of O. leucomelaena with OBP and other chemosensory-related proteins of other Coleoptera insects. Subsequently, MEGA7 was utilized for OBP sequence alignment and the construction of a phylogenetic tree, combined with expression profiling to screen for candidate antennae-specific OBPs. In addition, fumigation experiments with star anise volatiles were conducted to assess the antennae specificity of the candidate OBPs. Finally, molecular docking was employed to speculate on the binding potential of antennae-specific OBPs with star anise volatiles. The study identified 42 candidate OBPs, 8 chemosensory proteins and 27 receptors. OleuOBP3, OleuOBP5, and OleuOBP6 were identified as classic OBP family members specific to the antennae, which was confirmed by volatile fumigation experiments. Molecular docking ultimately clarified that OleuOBP3, OleuOBP5, and OleuOBP6 all exhibit a high affinity for ß-caryophyllene among the star anise volatiles. We successfully obtained three antennae-specific OBPs from O. leucomelaena and determined their high-affinity volatiles, providing a theoretical basis for the development of attractants in subsequent stages.
Asunto(s)
Escarabajos , Proteínas de Insectos , Simulación del Acoplamiento Molecular , Filogenia , Receptores Odorantes , Receptores Odorantes/genética , Receptores Odorantes/química , Receptores Odorantes/metabolismo , Animales , Proteínas de Insectos/genética , Proteínas de Insectos/química , Proteínas de Insectos/metabolismo , Escarabajos/genética , Escarabajos/metabolismo , Antenas de Artrópodos/metabolismo , Transcriptoma , Secuencia de Aminoácidos , Perfilación de la Expresión Génica , Conducta Animal/efectos de los fármacosRESUMEN
The green peach aphid, Myzus persicae, is a worldwide agricultural pest. Chlorpyrifos has been widely used to control M. persicae for decades, thus leading to a high resistance to chlorpyrifos. Recent studies have found that insect odorant binding proteins (OBPs) play essential roles in insecticide resistance. However, the potential resistance mechanism underlying the cross-link between aphid OBPs and chlorpyrifos remains unclear. In this study, two OBPs (MperOBP3 and MperOBP7) were found overexpressed in M. persicae chlorpyrifos-resistant strains (CRR) compared to chlorpyrifos-sensitive strains (CSS); furthermore, chlorpyrifos can significantly induce the expression of both OBPs. An in vitro binding assay indicated that both OBPs strongly bind with chlorpyrifos; an in vivo RNAi and toxicity bioassay confirmed silencing either of the two OBPs can increase the susceptibility of aphids to chlorpyrifos, suggesting that overexpression of MperOBP3 and MperOBP7 contributes to the development of resistance of M. persicae to chlorpyrifos. Our findings provide novel insights into insect OBPs-mediated resistance mechanisms.
Asunto(s)
Áfidos , Cloropirifos , Proteínas de Insectos , Resistencia a los Insecticidas , Insecticidas , Receptores Odorantes , Animales , Áfidos/genética , Áfidos/efectos de los fármacos , Áfidos/metabolismo , Cloropirifos/metabolismo , Cloropirifos/farmacología , Receptores Odorantes/genética , Receptores Odorantes/metabolismo , Receptores Odorantes/química , Resistencia a los Insecticidas/genética , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Proteínas de Insectos/química , Insecticidas/farmacología , Insecticidas/metabolismo , Prunus persica/genética , Prunus persica/parasitología , Prunus persica/metabolismo , Prunus persica/químicaRESUMEN
There are two main families of G protein-coupled receptors that detect odours in humans, the odorant receptors (ORs) and the trace amine-associated receptors (TAARs). Their amino acid sequences are distinct, with the TAARs being most similar to the aminergic receptors such as those activated by adrenaline, serotonin, dopamine and histamine. To elucidate the structural determinants of ligand recognition by TAARs, we have determined the cryo-EM structure of a murine receptor, mTAAR7f, coupled to the heterotrimeric G protein Gs and bound to the odorant N,N-dimethylcyclohexylamine (DMCHA) to an overall resolution of 2.9 Å. DMCHA is bound in a hydrophobic orthosteric binding site primarily through van der Waals interactions and a strong charge-charge interaction between the tertiary amine of the ligand and an aspartic acid residue. This site is distinct and non-overlapping with the binding site for the odorant propionate in the odorant receptor OR51E2. The structure, in combination with mutagenesis data and molecular dynamics simulations suggests that the activation of the receptor follows a similar pathway to that of the ß-adrenoceptors, with the significant difference that DMCHA interacts directly with one of the main activation microswitch residues, Trp6.48.
Asunto(s)
Microscopía por Crioelectrón , Receptores Acoplados a Proteínas G , Receptores Odorantes , Animales , Ratones , Sitios de Unión , Receptores Acoplados a Proteínas G/metabolismo , Receptores Acoplados a Proteínas G/química , Receptores Acoplados a Proteínas G/genética , Receptores Odorantes/metabolismo , Receptores Odorantes/química , Receptores Odorantes/genética , Simulación de Dinámica Molecular , Humanos , Odorantes/análisis , Unión Proteica , Ligandos , Células HEK293RESUMEN
Essential oils (EOs) are natural products currently used to control arthropods, and their interaction with insect odorant-binding proteins (OBPs) is fundamental for the discovery of new repellents. This in silico study aimed to predict the potential of EO components to interact with odorant proteins. A total of 684 EO components from PubChem were docked against 23 odorant binding proteins from Protein Data Bank using AutoDock Vina. The ligands and proteins were optimized using Gaussian 09 and Sybyl-X 2.0, respectively. The nature of the protein-ligand interactions was characterized using LigandScout 4.0, and visualization of the binding mode in selected complexes was carried out by Pymol. Additionally, complexes with the best binding energy in molecular docking were subjected to 500 ns molecular dynamics simulations using Gromacs. The best binding affinity values were obtained for the 1DQE-ferutidine (-11 kcal/mol) and 2WCH-kaurene (-11.2 kcal/mol) complexes. Both are natural ligands that dock onto those proteins at the same binding site as DEET, a well-known insect repellent. This study identifies kaurene and ferutidine as possible candidates for natural insect repellents, offering a potential alternative to synthetic chemicals like DEET.
Asunto(s)
Simulación del Acoplamiento Molecular , Aceites Volátiles , Receptores Odorantes , Receptores Odorantes/química , Receptores Odorantes/metabolismo , Aceites Volátiles/química , Animales , Proteínas de Insectos/química , Proteínas de Insectos/metabolismo , Simulación de Dinámica Molecular , Repelentes de Insectos/química , Ligandos , Relación Estructura-Actividad CuantitativaRESUMEN
Pheromone receptor (PR)-mediated transduction of sex pheromones to electrophysiological signals is the basis for sex pheromone communication. Orthaga achatina, a serious pest of the camphor tree, uses a mixture of four components (Z11-16:OAc, Z11-16:OH, Z11-16:Ald, and Z3,Z6,Z9,Z12,Z15-23:H) as its sex pheromone. In this study, we identified five PR genes (OachPR1-5) by phylogenetic analysis. Further RT-PCR and qPCR experiments showed that PR1-3 were specifically expressed in male antennae, while PR4 was significantly female-biased in expression. Functional characterization using the XOE-TEVC assay demonstrated that PR1 and PR3 both responded strongly to Z11-16:OH, while PR1 and PR3 had a weak response to Z3,Z6,Z9,Z12,Z15-23:H and Z11-16:Ald, respectively. Finally, two key amino acid residues (N78 and R331) were confirmed to be essential for binding of PR3 with Z11-16:OH by molecular docking and site-directed mutagenesis. This study helps understand the sex pheromone recognition molecular mechanism of O. achatina.
Asunto(s)
Proteínas de Insectos , Filogenia , Receptores Odorantes , Atractivos Sexuales , Atractivos Sexuales/química , Atractivos Sexuales/metabolismo , Animales , Receptores Odorantes/genética , Receptores Odorantes/metabolismo , Receptores Odorantes/química , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Proteínas de Insectos/química , Masculino , Femenino , Simulación del Acoplamiento Molecular , Alcoholes Grasos/metabolismo , Alcoholes Grasos/química , Alcoholes Grasos/farmacología , AldehídosRESUMEN
Odorant binding proteins (OBPs) are involved in odorant discrimination and act as the first filter in the peripheral olfactory system. Previous studies have shown that BhorOBP29 is potentially involved in olfactory perception in an important wood-boring pest Batocera horsfieldi (Hope) (Coleoptera: Cerambycidae), however, its function remains unclear. Here, we investigated the ligand-binding profiles of recombinant BhorOBP29 with 22 compounds from its host plant using fluorescence competitive binding assays and fluorescence quenching assays. The results showed that BhorOBP29 could bind to five ligands relying mainly on hydrophobic interactions. Molecular docking analysis indicated that residues Ile48, Leu51, Met52, Trp57, Asn105, and Val119 were extensively involved in the interactions between BhorOBP29 and the five ligands. Furthermore, the site-directed mutagenesis analysis revealed that Leu51 and Met52 residues were indispensable for BhorOBP29-ligands binding. Finally, electroantennogram (EAG) assays confirmed that hexanal, (-)-limonene, and 2-methylbutyraldehyde elicited a concentration-dependent EAG response with a maximum at the concentration of 1/10 v/v. These findings suggest that BhorOBP29 may play a significant role in the perception of host plant volatiles by B. horsfieldi. This study may help to discover novel behavioral regulation and environmentally friendly strategies for controlling B. horsfieldi in the future.
Asunto(s)
Escarabajos , Simulación del Acoplamiento Molecular , Unión Proteica , Receptores Odorantes , Compuestos Orgánicos Volátiles , Animales , Receptores Odorantes/química , Receptores Odorantes/metabolismo , Receptores Odorantes/genética , Escarabajos/metabolismo , Compuestos Orgánicos Volátiles/metabolismo , Compuestos Orgánicos Volátiles/química , Proteínas de Insectos/genética , Proteínas de Insectos/química , Proteínas de Insectos/metabolismo , Ligandos , Secuencia de Aminoácidos , Plantas/metabolismo , Plantas/químicaRESUMEN
Aethina tumida (small hive beetle, SHB) is a rapidly spreading invasive parasite of bee colonies. The olfactory system plays a key role in insect behavior, and odorant-binding proteins (OBPs) are involved in the first step of the olfactory signal transduction pathway and the detection of host volatiles. However, the olfactory mechanism of OBPs in SHB-localized bee colonies is unclear. In this study, electroantennogram (EAG) and behavioral bioassay showed that only three compounds (2-heptanone, ocimene, and ethyl palmitate) from bee colonies triggered high electrophysiological and behavioral responses. Three antenna-specific OBP genes (OBP6, OBP11, and OBP19) were identified, and they were significantly expressed on adult days 6-7. Furthermore, by combining RNA interference (RNAi) with EAG, olfactometer bioassay, competitive fluorescence binding assays, and molecular docking, we found that these three OBP genes were involved in the recognition of 2-heptanone and ethyl palmitate, and AtumOBP6 is also involved in the recognition of ocimene. These data indicate that AtumOBP6, AtumOBP11, and AtumOBP19 play an important role in the olfactory response to bee colony volatiles. Our results provide new insights into the functions of the OBP families in A. tumida and help to explore more potential target genes for environmentally friendly pest control strategies.
Asunto(s)
Escarabajos , Receptores Odorantes , Compuestos Orgánicos Volátiles , Animales , Receptores Odorantes/genética , Receptores Odorantes/metabolismo , Receptores Odorantes/química , Escarabajos/efectos de los fármacos , Compuestos Orgánicos Volátiles/farmacología , Compuestos Orgánicos Volátiles/química , Compuestos Orgánicos Volátiles/metabolismo , Abejas , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Proteínas de Insectos/química , Simulación del Acoplamiento Molecular , Antenas de Artrópodos/metabolismo , Antenas de Artrópodos/efectos de los fármacos , Conducta Animal/efectos de los fármacosRESUMEN
Glyphodes pyloalis Walker (Lepidoptera: Pyralidae) is the most destructive pest, causing severe damage to mulberry production in China's sericulture industry. The insecticide application in mulberry orchards poses a significant risk of poisoning to Bombyx mori. Shifting from insecticides to odor attractants is a beneficial alternative, but not much data is available on the olfactory system of G. pyloalis. We identified 114 chemosensory genes from the antennal transcriptome database of G. pyloalis, with 18 odorant-binding protein (OBP) and 17 chemosensory protein (CSP) genes significantly expressed in the antennae. Ligand-binding assays for two antennae-biased expressed general odorant-binding proteins (GOBPs) showed high binding affinities of GOBP1 to hexadecanal, ß-ionone, and 2-ethylhexyl acrylate, while GOBP2 exhibited binding to 4-tert-octylphenol, benzyl benzoate, ß-ionone, and farnesol. Computational simulations indicated that van der Waal forces predominantly contributed to the binding free energy in the binding processes of complexes. Among them, Phe12 of GOBP1 and Phe19 of GOBP2 were demonstrated to play crucial roles in their bindings to plant volatiles using site-directed mutagenesis experiments. Moreover, hexadecanal and ß-ionone attracted G. pyloalis male moths in the behavioral assays, while none of the candidate plant volatiles significantly affected female moths. Our findings provide a comprehensive understanding of the molecular mechanisms underlying olfactory recognition in G. pyloalis, setting the groundwork for novel mulberry pests control strategies based on insect olfaction.
Asunto(s)
Proteínas de Insectos , Mariposas Nocturnas , Receptores Odorantes , Animales , Receptores Odorantes/metabolismo , Receptores Odorantes/genética , Receptores Odorantes/química , Mariposas Nocturnas/metabolismo , Mariposas Nocturnas/genética , Proteínas de Insectos/metabolismo , Proteínas de Insectos/genética , Proteínas de Insectos/química , Masculino , Femenino , Antenas de Artrópodos/metabolismo , Compuestos Orgánicos Volátiles/metabolismoRESUMEN
Profiling of metabolites that contribute to the taste and odor of fruit products is important to produce the desired products. In this study, volatile and non-volatile compounds were analyzed using SPME/GC-MS and UHPLC-Q-Exactive-orbitrap-MS/MS, respectively. A total of 59 volatiles (including alcohols, aldehydes, acids, terpenes, ketones, phenols, and hydrocarbons et al.) and 18 non-volatiles (including phenolic acids, flavones, flavonoids, glucosides, phenols, and quinic acid derivatives et al.) were detected in dried Kirkir fruits. The binding interactions between the key volatiles and the detected non-volatiles with taste and olfactory receptors were also evaluated. Based on the molecular docking, 11 volatile compounds may contribute to the overall odor, while 16 non-volatile compounds may contribute to the taste of the Kirkir fruits. In conclusion, in silico studies can serve as a powerful technique for understanding mechanisms of interaction and predicting the key phytochemicals that contribute to the odor and taste of fruits.
Asunto(s)
Frutas , Simulación del Acoplamiento Molecular , Gusto , Compuestos Orgánicos Volátiles , Frutas/química , Frutas/metabolismo , Compuestos Orgánicos Volátiles/química , Compuestos Orgánicos Volátiles/metabolismo , Odorantes/análisis , Cromatografía de Gases y Espectrometría de Masas , Receptores Odorantes/química , Receptores Odorantes/metabolismo , Espectrometría de Masas en Tándem , Extractos Vegetales/química , Extractos Vegetales/metabolismo , Humanos , Cromatografía Líquida de Alta PresiónRESUMEN
Apriona germari (Hope) presents a significant threat as a dangerous wood-boring pest, inflicting substantial harm to forest trees. Investigating the olfactory sensory system of A. germari holds substantial theoretical promise for developing eco-friendly control strategies. To date, however, the olfactory perception mechanism in A. germari remains largely unknown. Therefore, we performed transcriptome sequencing of A. germari across four distinct body parts: antennae, foreleg tarsal segments, mouthparts (maxillary and labial palps), and abdomen terminals, pinpointing the odorant binding protein (OBP) genes and analyzing their expression. We found eight AgerOBPs (5, 19, 23, 25, 29, 59, 63, 70) highly expressed in the antennae. In our competitive binding experiments, AgerOBP23 showed strong binding abilities to the pheromone component fuscumol acetate, eight plant volatiles (farnesol, cis-3-hexenal, nerolidol, myristol acetate, cis-3-hexenyl benzoate, (-)-α-cedrene, 3-ethylacetophenone, and decane), and four insecticides (chlorpyrifos, phoxim, indoxacarb, and cypermethrin). However, AgerOBP29 and AgerOBP63 did not show prominent binding activities to these tested chemicals. Through homology modeling and molecular docking, we identified the key amino acid sites involved in the binding process of AgerOBP23 to these ligands, which shed light on the molecular interactions underlying its binding specificity. Our study suggests that AgerOBP23 may serve as a potential target for future investigations of AgerOBP ligand binding. This approach is consistent with the reverse chemical ecology principle, establishing the groundwork for future studies focusing on attractant or repellent development by exploring further the molecular interactions between OBP and various compounds.
Asunto(s)
Proteínas de Insectos , Receptores Odorantes , Receptores Odorantes/metabolismo , Receptores Odorantes/genética , Receptores Odorantes/química , Proteínas de Insectos/metabolismo , Proteínas de Insectos/genética , Proteínas de Insectos/química , Animales , Simulación del Acoplamiento Molecular , Filogenia , Feromonas/metabolismo , Feromonas/químicaRESUMEN
Odorant receptors (ORs) play a crucial role in insect chemoreception. Here, a female-biased odorant receptor MmedOR48 in parasitoid Microplitis mediator was fully functionally characterized. The qPCR analysis suggested that the expression level of MmedOR48 increased significantly after adult emergence and was expressed much more in the antennae. Moreover, an in situ hybridization assay showed MmedOR48 was extensively located in the olfactory sensory neurons. In two-electrode voltage clamp recordings, recombinant MmedOR48 was broadly tuned to 23 kinds of volatiles, among which five plant aldehyde volatiles excited the strongest current recording values. Subsequent molecular docking analysis coupled with site-directed mutagenesis demonstrated that key amino acid residues Thr142, Gln80, Gln282, and Thr312 together formed the binding site in the active pocket for the typical aldehyde ligands. Furthermore, ligands of MmedOR48 could stimulate electrophysiological activities in female adults of the M. mediator. The main aldehyde ligand, nonanal, aroused significant behavioral preference of M. mediator in females than in males. These findings suggest that MmedOR48 may be involved in the recognition of plant volatiles in M. mediator, which provides valuable insight into understanding the olfactory mechanisms of parasitoids.
Asunto(s)
Proteínas de Insectos , Receptores Odorantes , Compuestos Orgánicos Volátiles , Receptores Odorantes/genética , Receptores Odorantes/metabolismo , Receptores Odorantes/química , Femenino , Animales , Compuestos Orgánicos Volátiles/metabolismo , Compuestos Orgánicos Volátiles/química , Masculino , Proteínas de Insectos/metabolismo , Proteínas de Insectos/genética , Proteínas de Insectos/química , Avispas/química , Avispas/fisiología , Avispas/metabolismo , Simulación del Acoplamiento Molecular , Plantas/parasitología , Plantas/química , Plantas/metabolismoRESUMEN
The cotton whitefly, Bemisia tabaci, is considered as a species complex with 46 cryptic species, with Asia II-1 being predominant in Asia. This study addresses a significant knowledge gap in the characterization of odorant-binding proteins (OBPs) and chemosensory proteins (CSPs) in Asia II-1. We explored the expression patterns of OBPs and CSPs throughout their developmental stages and compared the motif patterns of these proteins. Significant differences in expression patterns were observed for the 14 OBPs and 14 CSPs of B. tabaci Asia II-1, with OBP8 and CSP4 showing higher expression across the developmental stages. Phylogenetic analysis reveals that OBP8 and CSP4 form distinct clades, with OBP8 appearing to be an ancestral gene, giving rise to the evolution of other odorant-binding proteins in B. tabaci. The genomic distribution of OBPs and CSPs highlights gene clustering on the chromosomes, suggesting functional conservation and evolutionary events following the birth-and-death model. Molecular docking studies indicate strong binding affinities of OBP8 and CSP4 with various odour compounds like ß-caryophyllene, α-pinene, ß-pinene and limonene, reinforcing their roles in host recognition and reproductive functions. This study elaborates on our understanding of the putative roles of different OBPs and CSPs in B. tabaci Asia II-1, hitherto unexplored. The dynamics of the expression of OBPs and CSPs and their interactions with odour compounds offer scope for developing innovative methods for controlling this global invasive pest.
Asunto(s)
Hemípteros , Proteínas de Insectos , Filogenia , Receptores Odorantes , Animales , Hemípteros/metabolismo , Hemípteros/genética , Receptores Odorantes/genética , Receptores Odorantes/metabolismo , Receptores Odorantes/química , Proteínas de Insectos/metabolismo , Proteínas de Insectos/genética , Proteínas de Insectos/química , Regulación del Desarrollo de la Expresión Génica , Simulación del Acoplamiento Molecular , Sesquiterpenos Policíclicos/metabolismo , Limoneno/metabolismo , Sesquiterpenos/metabolismoRESUMEN
Recently, various biosensors based on odorant-binding proteins (OBPs) were developed for the detection of odorants and pheromones. However, important data gaps exist regarding the sensitive and selective detection of aldehydes with various carbon numbers. In this work, an OBP2a-based electrochemical impedance spectroscopy (EIS) biosensor was developed by immobilizing OBP2a on a gold interdigital electrode, and was characterized by EIS and atomic force microscopy. EIS responses showed the OBP2a-based biosensor was highly sensitive to citronellal, lily aldehyde, octanal, and decanal (detection limit of 10-11 mol/L), and was selective towards aldehydes compared with interfering odorants such as small-molecule alcohols and fatty acids (selectivity coefficients lower than 0.15). Moreover, the OBP2a-based biosensor exhibited high repeatability (relative standard deviation: 1.6%-9.1 %, n = 3 for each odorant), stability (NIC declined by 3.6 % on 6th day), and recovery (91.2%-96.6 % on three real samples). More specifically, the sensitivity of the biosensor to aldehydes was positively correlated to the molecular weight and the heterocyclic molecule structure of the odorants. These results proved the availability and the potential usage of the OBP2a-based EIS biosensor for the rapid and sensitive detection of aldehydes in aspects such as medical diagnostics, food and favor analysis, and environmental monitoring.
Asunto(s)
Aldehídos , Técnicas Biosensibles , Receptores Odorantes , Técnicas Biosensibles/métodos , Aldehídos/química , Aldehídos/análisis , Receptores Odorantes/química , Receptores Odorantes/metabolismo , Técnicas Electroquímicas , Electrodos , Límite de Detección , Odorantes/análisis , Oro/química , Espectroscopía DieléctricaRESUMEN
Geosmin, a ubiquitous volatile sesquiterpenoid of microbiological origin, is causative for deteriorating the quality of many foods, beverages, and drinking water, by eliciting an undesirable "earthy/musty" off-flavor. Moreover, and across species from worm to human, geosmin is a volatile, chemosensory trigger of both avoidance and attraction behaviors, suggesting its role as semiochemical. Volatiles typically are detected by chemosensory receptors of the nose, which have evolved to best detect ecologically relevant food-related odorants and semiochemicals. An insect receptor for geosmin was recently identified in flies. A human geosmin-selective receptor, however, has been elusive. Here, we report on the identification and characterization of a human odorant receptor for geosmin, with its function being conserved in orthologs across six mammalian species. Notably, the receptor from the desert-dwelling kangaroo rat showed a more than 100-fold higher sensitivity compared to its human ortholog and detected geosmin at low nmol/L concentrations in extracts from geosmin-producing actinomycetes.
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Naftoles , Receptores Odorantes , Sesquiterpenos , Animales , Humanos , Naftoles/metabolismo , Naftoles/química , Naftoles/análisis , Sesquiterpenos/metabolismo , Sesquiterpenos/análisis , Sesquiterpenos/química , Receptores Odorantes/metabolismo , Receptores Odorantes/genética , Receptores Odorantes/química , Ratas , Feromonas/metabolismo , Feromonas/química , Feromonas/análisis , Odorantes/análisisRESUMEN
In Bactrocera dorsalis, both males and females release chemical signals to attract mates. In our previous study, we identified ethyl laurate, ethyl myristate, and ethyl palmitate as potent female-derived pheromones that contribute to mate attraction. However, the mechanisms underlying the olfactory recognition remain unclear. In this study, we observed strong antennal and behavioral responses in male B. dorsalis to these female-derived pheromones, and further investigation revealed significant upregulation of OBP49a and OBP83b following exposure to these compounds. Through fluorescence competitive binding assays and RNA interference techniques, we demonstrated the crucial roles of OBP49a and OBP83b in detecting female-derived pheromones. Finally, molecular docking analysis identified key residues, including His134 in OBP83b and a lysine residue in OBP49a, which formed hydrogen bonds with female-derived pheromones, facilitating their binding. These findings not only advance our understanding of olfactory recognition of pheromones in B. dorsalis but also offer potential targets for developing olfaction-interfering techniques for pest control.
Asunto(s)
Proteínas de Insectos , Tephritidae , Animales , Femenino , Tephritidae/metabolismo , Tephritidae/química , Tephritidae/fisiología , Tephritidae/genética , Proteínas de Insectos/metabolismo , Proteínas de Insectos/química , Proteínas de Insectos/genética , Masculino , Receptores Odorantes/metabolismo , Receptores Odorantes/química , Receptores Odorantes/genética , Atractivos Sexuales/química , Atractivos Sexuales/metabolismo , Simulación del Acoplamiento Molecular , Feromonas/metabolismo , Feromonas/química , OlfatoRESUMEN
Insects detect and discriminate a diverse array of chemicals using odorant receptors (ORs), which are ligand-gated ion channels comprising a divergent odorant-sensing OR and a conserved odorant receptor co-receptor (Orco). In this work, we report structures of the ApOR5-Orco heterocomplex from the pea aphid Acyrthosiphon pisum alone and bound to its known activating ligand, geranyl acetate. In these structures, three ApOrco subunits serve as scaffold components that cannot bind the ligand and remain relatively unchanged. Upon ligand binding, the pore-forming helix S7b of ApOR5 shifts outward from the central pore axis, causing an asymmetrical pore opening for ion influx. Our study provides insights into odorant recognition and channel gating of the OR-Orco heterocomplex and offers structural resources to support development of innovative insecticides and repellents for pest control.
Asunto(s)
Acetatos , Áfidos , Proteínas de Insectos , Receptores Odorantes , Receptores Odorantes/química , Receptores Odorantes/metabolismo , Receptores Odorantes/genética , Animales , Proteínas de Insectos/química , Proteínas de Insectos/metabolismo , Proteínas de Insectos/genética , Áfidos/química , Acetatos/química , Acetatos/metabolismo , Ligandos , Terpenos/química , Terpenos/metabolismo , Odorantes/análisis , Subunidades de Proteína/química , Subunidades de Proteína/metabolismo , Activación del Canal Iónico , Microscopía por Crioelectrón , Monoterpenos AcíclicosRESUMEN
Most insects, including human-targeting mosquitoes, detect odors through odorant-activated ion channel complexes consisting of a divergent odorant-binding subunit (OR) and a conserved co-receptor subunit (Orco). As a basis for understanding how odorants activate these heteromeric receptors, we report here cryo-electron microscopy structures of two different heteromeric odorant receptor complexes containing ORs from disease-vector mosquitos Aedes aegypti or Anopheles gambiae. These structures reveal an unexpected stoichiometry of one OR to three Orco subunits. Comparison of structures in odorant-bound and unbound states indicates that odorant binding to the sole OR subunit is sufficient to open the channel pore, suggesting a mechanism of OR activation and a conceptual framework for understanding evolution of insect odorant receptor sensitivity.
Asunto(s)
Aedes , Anopheles , Microscopía por Crioelectrón , Proteínas de Insectos , Odorantes , Receptores Odorantes , Animales , Aedes/fisiología , Anopheles/fisiología , Proteínas de Insectos/química , Proteínas de Insectos/metabolismo , Multimerización de Proteína , Subunidades de Proteína/química , Subunidades de Proteína/metabolismo , Receptores Odorantes/química , Receptores Odorantes/metabolismoRESUMEN
Aphidius gifuensis is the dominant parasitic natural enemy of aphids. Elucidating the molecular mechanism of host recognition of A. gifuensis would improve its biological control effect. Chemosensory proteins (CSPs) play a crucial role in insect olfactory systems and are mainly involved in host localization. In this study, a total of nine CSPs of A. gifuensis with complete open reading frames were identified based on antennal transcriptome data. Phylogenetic analysis revealed that AgifCSPs were mainly clustered into three subgroups (AgifCSP1/2/7/8, AgifCSP3/9, and AgifCSP4/5/6). AgifCSP2/5 showed high expression in the antennae of both sexes. Moreover, AgifCSP5 was found to be specifically expressed in the antennae. In addition, fluorescent binding assays revealed that AifCSP5 had greater affinities for 7 of 32 volatile odor molecules from various sources. Molecular docking and site-directed mutagenesis results revealed that the residue at which AgifCSP5 binds to these seven plant volatiles is Tyr75. Behavior tests further confirmed that trans-2-nonenal, one of the seven active volatiles in the ligand binding test, significantly attracted female adults at a relatively low concentration of 10 mg/mL. In conclusion, AgifCSP5 may be involved in locating aphid-infested crops from long distances by detecting and binding trans-2-nonenal. These findings provide a theoretical foundation for further understanding the olfactory recognition mechanisms and indirect aphid localization behavior of A. gifuensis from long distances by first identifying the host plant of aphids.
Asunto(s)
Áfidos , Proteínas de Insectos , Filogenia , Animales , Áfidos/genética , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Proteínas de Insectos/química , Femenino , Masculino , Interacciones Huésped-Parásitos/genética , Antenas de Artrópodos/metabolismo , Simulación del Acoplamiento Molecular , Secuencia de Aminoácidos , Receptores Odorantes/genética , Receptores Odorantes/química , Receptores Odorantes/metabolismo , Avispas/genética , Avispas/fisiologíaRESUMEN
Insect olfactory receptors (ORs) are seven-transmembrane domain ion channels that function by forming heteromeric complexes with olfactory receptor co-receptors (Orcos). In this study, we investigated the potential for enhancing sensitivity of odor detection and responsivity through genetic modification of Orcos, considering its wider application in odor sensing. First, we measured the intensity of response to 1-octen-3-ol for the mosquito Aedes aegypti OR (AaOR8) when complexed individually with an Orco from the same mosquito (AaOrco), the honeybee Apis mellifera (AmOrco), the silkworm Bombyx mori (BmOrco), or the fruit fly Drosophila melanogaster (DmOrco). Relative to the other Orcos, AmOrco demonstrated higher sensitivity and responsivity, with a 1.8 to 21-fold decrease in the half-maximal effective concentration (EC50) and a 1.6-8.8-fold increase in the maximal effect (Emax), respectively. Furthermore, AmOrco co-expressed with AaOR10, BmOR56, or DmOR47a showed higher sensitivity and responsivity than AaOrco, BmOrco, or DmOrco co-expressed with their respective ORs. To further increase sensitivity and responsivity, we engineered chimeric Orcos by fusing AmOrco with DmOrco, considering the domain characteristics of Orcos. The response to 1-octen-3-ol was evaluated for AaOR8 when complexed individually with AmOrco, as well as for a mutant that combines DmOrco from the N-terminal (NT) to the C-terminal region of the fourth transmembrane domain (TM4) with the region of AmOrco following TM4 (Dm[NT-TM4]AmOrco). When compared to AmOrco, Dm(NT-TM4)AmOrco showed higher sensitivity and responsivity, with a 1.4-fold decrease in the EC50 and a 1.4-fold increase in the Emax, respectively. In addition, Dm(NT-TM4)AmOrco co-expressed with either DmOR47a or BmOR56 demonstrated higher sensitivity and responsivity than AmOrco co-expressed with their respective ORs. These results suggest that AmOrco could be a relatively more sensitive Orco, and further enhancement of sensitivity and responsivity could be achieved through recombination with heterologous Orcos near the TM4 of AmOrco.
Asunto(s)
Odorantes , Receptores Odorantes , Animales , Receptores Odorantes/genética , Receptores Odorantes/metabolismo , Receptores Odorantes/química , Odorantes/análisis , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Bombyx/genética , Bombyx/metabolismo , Aedes/genética , Aedes/metabolismo , Proteínas Recombinantes de Fusión/metabolismo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/química , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Proteínas de Insectos/química , Abejas/metabolismo , Abejas/genética , Células HEK293 , OctanolesRESUMEN
Indole is widely present in nature and contributes significantly to the smell of flowers and animal excretion. However, the odor perception mechanism for indole is unclear, despite previous reports suggesting that it activates the Olfr740 family of receptors. In this study, we successfully identified another receptor, Olfr205, that is responsive to indole. Molecular model construction and binding pocket analysis predicted that the A202 residue in transmembrane helix 5 of Olfr205 forms a crucial hydrogen bond with indole, facilitating receptor activation. Additionally, G112 in transmembrane helix 3 of the Olfr740 family is involved in indole activation of receptors. Finally, our mutant function assay showed that substitution of A202 in Olfr205 and G112 in Olfr740 with other amino acids significantly decreased the receptor response to indole, which provides robust evidence to confirm the docking results. In summary, our study is the first to reveal that Olfr205 is an olfactory receptor distinct from those in the Olfr740 family that is activated by indole. Moreover, these receptors display different indole-binding mechanisms. This study sheds light on molecular binding mechanisms and contributes to a deeper understanding of indole perception.