Search Results (234)

The polyphagous pest Oxycetonia jucunda Faldermann can cause substantial damage to a range of economically important crops, with the adult beetles feeding directly on floral tissues and young leaves. RT-qPCR is widely used to analyze gene expression, for which the selection of stable reference genes is essential for enabling an accurate normalization of expression. However, no systematic evaluations of suitable reference genes for RT-qPCR analysis using different tissues of O. jucunda have been conducted. To assess their applicability as reliable normalization controls, we used five computational methods to examine the stability of seven potential reference genes (GAPDH, EF1α, RPS3, RPS18, RPL18, RPS31, and UBC5A) across six adult tissues, with three biological replicates per tissue. The findings revealed RPS3 and RPS31 to be the most stably expressed. This pair of reference genes was further validated by normalizing the expression of the odorant-binding protein 3 (OBP3) target gene. Our findings will provide important foundational data for the accurate analysis of functional gene expression in O. jucunda. Full article

The Colorado potato beetle (CPB) is the primary defoliator of potatoes and is notorious for its ability to develop resistance to various insecticides. This remarkable adaptability may partly reflect selective pressures imposed due to the beetle’s coevolution with toxic Solanaceous host plants. As the initial interface between the environment and the insect olfactory system, odorant-binding proteins (OBPs) may sequester excess harmful molecules, such as insecticides and plant allelochemicals, in the perireceptor space, mitigating deleterious effects on vulnerable olfactory sensory neuronal dendrites. In this study, we identified an antenna-specific OBP (LdecOBP33) that is significantly upregulated in a pesticide resistant strain compared to a susceptible one. Competitive displacement fluorescence binding assays demonstrated that the LdecOBP33 protein exhibited broad affinity toward a range of plant volatiles and insecticides. Silencing LdecOBP33 decreased the beetle’s resistance to imidacloprid and impaired its ability to locate host plants. Together, these findings provide insight into a key molecular factor involved in the CPB’s response to environmental challenges, suggesting a potential link between insects’ adaptation to xenobiotics and their olfactory processing. Full article

Tribolium castaneum, the red flour beetle, is both a major pest of stored products and a valuable genetic model. Odorant Binding Proteins (OBPs), traditionally associated with olfaction, are now recognized as multifunctional, contributing to detoxification, immunity, and reproduction. This review synthesizes recent advances in the molecular structure, gene expression, and functional characterization of T. castaneum OBPs—particularly TcOBPC11, TcOBPC12, TcOBPC17, and TcOBP7G. Experimental evidence, including RNA interference, ligand-binding assays, and expression profiling, supports their role in defense against xenobiotics. Comparative genomic analyses reveal lineage-specific expansions and adaptive evolution, especially in Minus-C OBPs. Translational applications include RNA interference (RNAi)-based pest control, OBP-targeting repellents, and biosensors. Outstanding challenges remain, including structural resolution and functional redundancy. Future research integrating CRISPR, single-cell transcriptomics, and structural biology will be critical to decode OBP regulatory networks and leverage their potential in pest management and biotechnology. Full article

Plutella xylostella, a major pest of cruciferous vegetables, depends predominantly on chemoreception to locate host plants. Legs are crucial in insect chemical perception, particularly during close-range and contact chemoreception. However, the molecular basis underlying the chemosensory repertoire in P. xylostella legs remains elusive. To address this, we sequenced chemosensory-related genes in diamondback moth legs. Sequencing identified 32 odorant binding protein (OBP), 18 chemosensory protein (CSP), 26 odorant receptor (OR), 20 gustatory receptor (GR), 15 ionotropic receptor (IR), and 3 sensory neuron membrane protein (SNMP) genes. Comparative analysis with antennal transcriptome data revealed three CSPs, seven ORs, and two GRs newly identified in the legs. Transcriptome analysis showed higher fragments per kilobase of transcript per million mapped reads values for CSPs than for other chemosensory-related gene families. Furthermore, qRT-PCR confirmed the highest expression of PxylCSP9 in the legs, suggesting its role in perceiving external compounds. Fluorescent binding assays revealed high binding affinity of PxylCSP9 for several host plant semiochemicals. Molecular docking predicted a hydrophobic binding pocket in PxylCSP9 with Met11, Leu13, and Leu43 frequently participating in ligand interactions. Our findings indicate that leg-enriched PxylCSP9 is pivotal for host plant recognition during close-range chemoreception, suggesting its potential as a molecular target for precision management through behavior-based strategies. Full article

The mechanism by which odorants are recognized by olfactory receptors remains primarily unresolved. While charge transport is believed to play a significant role, its precise nature is still unclear. Here, we present a novel perspective by exploring the interplay between the intrinsic energy scales of odorant molecules and the gap states that facilitate intermolecular charge transport. We find that odorants act as weak tunneling conductors mainly because of the limited magnitude of electronic coupling between frontier molecular levels. This behavior is further connected to electron–phonon interaction and reorganization energy, suggesting that physically meaningful values for the latter parameter emerge only in the deep off-resonant tunneling regime. These findings complement the swipe card model of olfaction, in which an odorant needs both the right shape to bind to a receptor and the correct vibrational frequency to trigger signal transduction. Moreover, they reveal that the underlying mechanisms are much more complex than previously assumed. Full article

The red flower aphid (Uroleucon gobonis) is a significant agricultural pest causing damage via direct feeding and virus transmission. Chemical sensory proteins (CSPs) are critical for insecticide resistance, mediating the detection of semiochemicals or the sequestration of neuroactive insecticides. This study provides the first comprehensive identification and functional characterization of chemosensory gene families in Uroleucon gobonis to elucidate their roles in chemoperception and resistance. We conducted de novo transcriptome sequencing and assembly to identify chemosensory genes. Their phylogenetic relationships and structural motifs were analyzed. Developmental expression patterns were assessed via RNA-seq, and tissue-specific expression was validated using quantitative real-time PCR (qRT-PCR). We identified 40 chemosensory genes: 12 odorant-binding proteins (OBPs), 8 CSPs, 14 odorant receptors (ORs), and 6 gustatory receptors (GRs). Phylogenetic analysis revealed species-specific adaptations, including the absence of GR clades 2/4 and minimal representation in CSP Subgroup III. Structural motifs were highly conserved in ORs/OBPs but divergent in CSPs/GRs. RNA-seq identified 1896 differentially expressed genes (DEGs) between instars, including stage-specific regulation of UgobCSP4, UgobCSP6, UgobOBP3, and UgobOBP10. qRT-PCR confirmed extreme spatial expression, such as leg-specific UgobCSP6 and antennae-specific UgobOBP10. These findings elucidate key molecular adaptations in chemosensory gene families governing perception and potential insecticide resistance in Uroleucon gobonis. The identified stage- and tissue-specific genes provide targets for developing species-specific pest control strategies. Full article

Olfactory perception depends on soluble proteins in the perireceptor environment that support odorant transport, mucosal protection, and tissue homeostasis. In insects, odorant-binding proteins (OBPs) in the sensillum lymph are indispensable for odor detection, whereas in humans the indispensability of OBPs (OBP2A/2B) remains unclear because they are inconsistently detected in nasal mucus. Consequently, it remains unclear whether other soluble proteins compensate for this function or how they contribute to odorant processing and signal transmission within the olfactory mucus. Accumulating evidence indicates that OBP-like lipocalins (LCN1, LCN2, LCN15) and apolipoprotein D, together with bactericidal/permeability-increasing (BPI)-fold proteins, act as major mediators of odorant solubilization, antimicrobial defense, oxidative stress regulation, and extracellular matrix (ECM) remodeling. Alterations in those proteins and ECM organization are linked to idiopathic and age-related smell loss, chronic rhinosinusitis, and neurodegenerative disorders, underscoring their broad relevance at the interface of chemosensation, mucosal defense, and brain health. Major unresolved issues include the functional indispensability of human OBPs, the receptor-specific contributions of OBP-like proteins, and the mechanistic relationships linking olfactory proteome remodeling, sensory signaling, and disease progression. This review provides an integrative overview of structural and mechanistic insights, highlights current controversies, and proposes future research directions, including receptor–protein mapping, integrated structural–functional studies, structural–functional analysis of OBP–ECM networks, and clinical validation of OBP-related biomarkers. Full article

Odorant receptors (ORs) in Drosophila melanogaster represent important proteins of the insect’s olfactory system, enabling the detection of environmental cues such as food sources, host plants, and mating signals. Their modulation by natural ligands offers a sustainable strategy for pest management, particularly through the use of bioactive compounds obtained from agricultural crop and food production residues (ACFPR). In this study, as a model we employed the AlphaFold-predicted structure of the odorant receptor Q9W1P8 for structure-based virtual screening. Molecular docking was carried out using GNINA, a deep learning-enhanced docking tool. Screening of 164 ACFPR-derived compounds from different sources revealed several strong binders, including α-tomatine, peonidin 3-rutinoside, and cinnamtannin B1. Predicted binding modes support the role of plant-derived molecules as candidate modulators of insect olfactory receptors. These findings highlight the utility of integrating AlphaFold models with advanced docking platforms to support the development of sustainable pest management strategies. Full article

Insects rely heavily on olfaction to regulate essential behaviors such as host location, oviposition and mating. The invasive cotton mealybug, Phenacoccus solenopsis Tinsley represents a global threat to cotton and numerous cultivated crops. To elucidate the molecular basis of its olfaction mechanisms, we sequenced and assembled antennal transcriptomes from male and female adults using Illumina NovaSeq X Plus technology. Among 13,891 unigenes, 91 chemosensory genes were identified, including 40 odorant receptors, 13 gustatory receptors, 19 ionotropic receptors, 10 odorant-binding proteins, 7 chemosensory proteins, and 2 sensory neuron membrane proteins. Differential expression analysis revealed 6312 genes with significant sex-biased expression between male and female antennae, including 55 chemosensory genes. Phylogenetic analyses further clarified the evolutionary relationships of these chemosensory genes with homologs from other hemipteran species. Notably, validation confirmed that 18 PsolORs were male-biased. This comprehensive transcriptomic study establishes a foundation for further functional characterization of pheromone reception and provides valuable candidate genes for dissecting chemoreception mechanisms in P. solenopsis. Full article

Bactrocera dorsalis Hendel is a devastating invasive pest that costs billions of dollars in agricultural losses worldwide. Current control strategies rely heavily on male-specific attractants such as methyl eugenol, which are less effective against females, underscoring the need for female-targeted control approaches. Here, we investigated the molecular mechanisms underlying female attraction to cis-linalool oxide by functionally characterizing the odorant receptor OR45a, identifying it as a molecular target for female-oriented pest management. We conducted spatiotemporal expression analysis of OR45a in response to cis-linalool oxide, followed by RNAi and behavioral assays. Phylogenetic analysis of OR45a orthologs from 10 Dipteran species, combined with structural topology prediction and solvent-accessible surface area (ASA) analysis, helped identify functional domains and residues. Site-directed mutagenesis and two-electrode voltage clamp (TEVC) recordings validated receptor–ligand interactions. Results showed that OR45a was specifically upregulated in antennae, with peak expression at 10 days post-eclosion, coinciding with oviposition periods. RNAi significantly reduced OR45a transcript levels and female behavioral responses to cis-linalool oxide. Phylogenetic analysis showed that OR45a is highly conserved within Tephritidae but diverges from Drosophilidae, with closest similarity to Anastrepha ludens, indicating ecological specialization. Structural modeling predicted a canonical seven-transmembrane architecture with three extracellular loops forming the ligand-binding pocket. Among five key residues identified, Leu122 and Ile146 were essential for ligand recognition, while Tyr107 contributed to protein stability. These findings reveal a female-specific odorant receptor mechanism in B. dorsalis and provide molecular targets for OR45a-based attractants, addressing a critical gap in female-focused pest management. Full article

Anastatus orientalis, a prominent egg parasitoid of Lycorma delicatula, demonstrates considerable potential for biological control. A. orientalis is dependent on host volatiles to identify and locate appropriate hosts for reproduction, with its olfactory system playing a vital role in volatile detection. There is little known about the chemosensory genes in A. orientalis. Therefore, here, we conducted a transcriptome analysis of the males and females from A. orientalis. Overall, 24 odorant binding proteins (OBPs), 4 chemosensory proteins (CSPs), 26 odorant receptors (ORs), 3 gustatory receptors (GRs), 3 ionotropic receptors (IRs), and 2 sensory neuron membrane proteins (SNMPs) were identified by transcriptome analysis. The values for fragments per kilobase per million (FPKM) indicated that the chemosensory protein gene families in A. orientalis exhibit different expression levels in male and female adults, with some genes showing significant differences and displaying sex-biased expression. Furthermore, RACE technology, phylogenetic analysis, and expression analysis were used to investigate the role that AoOBP8 plays in olfaction in A. orientalis. AoOBP8 was highly expressed in females and the heads of adults, indicating that the gene has a crucial role to play in the search for hosts and in oviposition in female adults, while the head is crucial in recognizing chemical information. These results contribute to a deeper understanding of the functions of chemosensory protein gene families in A. orientalis and offer a reference for developing biocontrol methods for forestry pests. Full article

This study employed a combined computational and experimental approach to investigate the molecular recognition mechanism of 4-methylphenol by human olfactory receptor hOR9Q2. The strategy integrated molecular docking using BIOVIA Discovery Studio, structural modeling of hOR9Q2 based on the AlphaFold2-predicted, molecular dynamics simulations with GROMACS software employing the AMBER14SB force field, and systematic site-directed mutagenesis validation. Computational simulations revealed that the binding cavity formed by transmembrane domains TM3, TM5, and TM6 serves as the key interaction region, with van der Waals, hydrophobic, and Pi-sulfur interactions driving stable binding (ΔG = −40.173 ± 0.34 kJ/mol). Functional characterization identified six critical residues (Cys112, Val158, Met207, Phe251, Leu255, and Tyr259) as essential for receptor activation, while mutations at Ile71 and Ala108 resulted in partial functional impairment. This study reveals the structural basis for hOR9Q2’s selective response to 4-methylphenol, while establishing a computational–experimental framework for precisely locating functional sites on olfactory receptors. These findings elucidate the molecular mechanism of odorant recognition and provide insights for developing odorant prediction models and designing specific olfactory receptor modulators. Full article

Gynaephora qinghaiensis is a major grassland pest common in the alpine meadows of the western plateau of China, and its biological behavior is affected by the synergy of a variety of chemicals in the environment. OBPs can dissolve and transport odor molecules such as volatile plant compounds through lymphatic fluid, which plays an important olfactory-to-olfactory role. However, the specific function of OBPs in the interaction mechanism between moths and volatile plant compounds is still unknown. The purpose of this study was to analyze the binding characteristics of GqinOBP10 and its volatile plant compounds in moths and to explore its role in the olfactory perception mechanism of moths so as to study the corresponding target ligands and achieve green control. The purified GqinOBP10 was subjected to fluorescence competitive binding to eight ligands. The 3D modeling of GqinOBP10 was carried out by the SWISS-MODEL website, and the molecular docking was carried out by Autodock 4.2.6 software, and the binding of GqinOBP10 to eight ligands was simulated and verified. The results showed that the cloned strain with the full length of GqinOBP10 was cloned. The fluorescence competition binding results showed that GqinOBP10 had strong binding ability to eight volatile plant compounds, among which the binding ability to 2-Amino-1-phenylethanol and 2-Oleoylglycerol was the strongest, and had high binding ability with the other six ligands. The molecular docking results showed that the binding energy of GqinOBP10 and eight odorant molecules was negative, and all of them could form 1~4 hydrogen bond for binding, among which the binding performance with 2-Oleoylglycerol was the best. The findings suggest that dsOBP10 injection leads to a notable decrease in both the expression levels of GqinOBP10 and the antennal potential response in male and female tissues. This indicates that GqinOBP10 is likely crucial for the localization and recognition of host plants in G. qinghaiensis. By silencing GqinOBP10, the olfactory perception of host volatiles is significantly impaired, highlighting the protein’s importance in the caterpillars’ ability to detect and respond to their environment. These insights provide a valuable basis for developing targeted attractants, potentially enhancing pest management strategies by manipulating olfactory cues in these caterpillars. Further research could explore the specific mechanisms by which GqinOBP10 influences olfactory perception and host plant selection. Full article

Varroa destructor is a major health problem for honey bees (Apis mellifera). Selective breeding of Varroa-resistant bees is a suitable long-term solution to Varroa parasitism. After three generations of selecting honey bees for lower (resistant) and higher (susceptible) V. destructor population growth (LVG and HVG, respectively), LVG bees showed increased behavioral, cellular, and humoral immunity against Varroa. To further analyze resistance, the transcriptomes of both bee genotypes were examined, revealing that parasitized LVG bees had fewer differentially expressed genes (DEGs) than parasitized HVG bees, indicating a reduced impact by Varroa with greater resistance. Annotations of the altered DEGs showed that both genotypes were affected with an increased demand for energy, protein, and repair during parasitism. However, there were also DEGs in LVG bees, possibly related to resistance, such as up-regulation of odorant binding protein genes and down-regulation of the corazonin receptor gene, whereas DEGs in the HVG bees may be more related to stress, such as up-regulation of ATP synthase and down-regulation of the transcription factor dorsal. Overall, this work shows that selection for LVG and HVG bees resulted in genotypes with widespread differences in gene expression during Varroa parasitism, which may be related to resistance and susceptibility. Full article

Insecticide resistance has become a critical issue threatening global agricultural production and food security. Previous studies have primarily focused on resistance mechanisms such as target-site mutations, enhanced metabolic detoxification, and reduced cuticular penetration. However, growing evidence in recent years indicates that odorant-binding proteins (OBPs) and chemosensory proteins (CSPs)—beyond their roles in chemoreception—also play key roles in the development of insecticide resistance. Research has revealed that these proteins significantly modulate insect susceptibility to insecticides through various mechanisms, including direct binding to insecticides, regulation of detoxification metabolic pathways, and influence on behavioral adaptations in pests. This review also systematically summarizes modern research strategies employed to investigate OBPs/CSPs functions, including high-throughput omics technologies, RNA interference, CRISPR-Cas9 gene editing, and molecular docking, while discussing the potential of targeting these proteins for developing novel insecticides and resistance management strategies. Although significant progress has been made in laboratory studies, the practical application of OBPs/CSPs-mediated resistance mechanisms still faces multiple challenges. Future research should prioritize multi-gene targeting strategies, cross-species functional validation, and field trial implementation to facilitate the development of green and precise pest control approaches based on OBPs and CSPs, thereby offering new pathways for sustainable agriculture. Full article