Search Results (142)

Background: Chemoreception plays a central role in how insects perceive environmental chemical cues and regulate essential behaviors. Mayflies (Ephemeroptera), among the earliest-diverging lineages of winged insects, are important bioindicators of freshwater ecosystems, yet their chemosensory gene repertoire remains poorly characterized. Methods: Using the high-quality genome of Parafronurus youi, we conducted a genome-wide identification and comparative analysis of six major chemosensory gene families. Results: We identified 72 candidate chemosensory genes, including 10 OBPs, 15 CSPs, 9 ORs, 14 GRs, 23 IRs, and 1 SNMP. These gene families differed markedly in physicochemical properties, conserved motifs, domain architecture, gene structure, chromosomal distribution, and phylogenetic relationships. Chemosensory genes were unevenly distributed across the 11 chromosomes, with several families showing clustered organization, whereas no obvious collinear relationships were detected. Compared with representative terrestrial insects, P. youi possesses a comparatively compact chemosensory repertoire, although this comparison should be interpreted cautiously because data sources and annotation strategies differ among studies. Different gene families showed distinct evolutionary patterns, including structurally conserved soluble binding proteins and co-receptors, limited diversification in several receptor families, and a comparatively well-represented IR repertoire. Conclusions: This study provides the first genome-wide overview of chemosensory genes in Ephemeroptera and offers a basis for future functional and evolutionary studies of chemoreception in palaeopteran insects. Full article

Rhoptroceros cyatheae (Hymenoptera: Selandriidae) is a dominant herbivorous pest of Alsophila spinulosa in southwestern China, including Guizhou and Sichuan provinces. Infestation by this pest impairs spore reproduction of A. spinulosa and reduces the photosynthetic capacity of host plants. However, the chemosensory genes of R. cyatheae have not been reported, and the molecular basis of antennal detection of host volatile organic compounds (VOCs) is poorly understood. This study aims to screen and identify bioactive VOCs potentially involved in host searching behavior of R. cyatheae, analyze antennal VOC detection patterns, and explore the in vitro binding characteristics of an odorant-binding protein (OBP) involved in olfactory recognition, thereby providing a preliminary theoretical basis for the green management of R. cyatheae. Dynamic headspace sampling, gas chromatography-mass spectrometry (GC-MS), and gas chromatography-electroantennography (GC-EAD) were used to measure antennal electrophysiological responses of R. cyatheae to volatiles from its host A. spinulosa. Y-tube olfactometer assays were conducted to evaluate behavioral responses. For RcyaOBP7, fluorescence competitive binding assays, structural modeling, and molecular docking were integrated to investigate its in vitro binding characteristics with nine selected bioactive VOCs. Nine A. spinulosa volatiles were identified that elicited antennal electrophysiological responses in R. cyatheae, and the sawfly showed behavioral orientation to these VOCs, confirming that its antennae can detect host VOCs. In vitro binding assays showed that RcyaOBP7 exhibited strong binding affinity to p-ethylacetophenone, suggesting its potential involvement in antennal olfactory recognition of this volatile. Specific VOCs released by A. spinulosa are among the signaling molecules detected by the antennae of R. cyatheae. In vitro findings indicate that RcyaOBP7 binds specifically to p-ethylacetophenone, suggesting a possible role in antennal olfactory recognition and behaviors such as host location. However, in vivo functional validation and field trials under ecologically relevant conditions are needed to confirm these roles. This study characterizes the in vitro binding properties of RcyaOBP7 and provides a basis for further research on green management strategies for R. cyatheae based on antennal olfactory signals. Full article

The olfactory and gustatory systems are essential for survival, enabling organisms to detect and respond to environmental chemical cues. Although canonical signaling pathways in smell and taste have been well defined, growing evidence highlights additional ion channel families as key modulators of sensory responses. Recent studies identify the anoctamin, transmembrane channel-like, and TMEM63 superfamily as a class of non-canonical sensory effectors that regulate signal amplification, excitability, and epithelial homeostasis across chemosensory systems. In the mammalian olfactory epithelium, specific anoctamin channels enhance odor-evoked responses and contribute to tissue homeostasis. In the gustatory system, salt detection is now understood to involve multiple parallel signaling pathways, with TMC4 emerging as a key contributor to high-salt and salt-associated taste sensing. These channel families are evolutionarily conserved across species, including C. elegans, Drosophila, and aquatic organisms, where they mediate chemosensation, mechanosensation, humidity detection, and osmoregulation. This functional versatility is supported by a shared structural architecture that enables selective ion conduction and, in some members, regulated phospholipid scrambling. This review proposes a unifying framework in which anoctamin and transmembrane channel-like proteins act as multimodal regulators of sensory signaling, linking environmental cues to cellular excitability and microenvironmental control and highlighting new principles of chemosensory organization and therapeutic potential. Full article

Agricultural pests can rapidly adapt to chemical pressures, and expression-based surveys of chemosensory genes may not fully capture the associated genomic variation. We hypothesized that the molecular profiles of chemosensory and detoxification genes in the mulberry thrips Pseudodendrothrips mori Niwa (Thysanoptera: Thripidae) are associated with local genomic variability and methylation context alongside transcript abundance. To explore this, we integrated PacBio HiFi-derived single-nucleotide polymorphisms (SNPs), structural variants (SVs), DNA methylation, and RNA-seq data on a chromosome-level reference genome. We analyzed 179 focal genes from six families, applying a consensus prioritization framework—based on weighted percentiles of feature values, principal component distances, and anomaly-detection scores—to rank the candidates. The integrated priority score correlated positively with SNP (r = 0.603) and SV burden (r = 0.632) and negatively with local methylation (r = −0.524), whereas its correlation with expression was weaker (r = 0.427). Three OBPs—PSMOgene01223, PSMOgene012530, and PSMOgene012982—emerged among the highest-priority candidates, exhibiting favorable in silico docking scores (−5.038 to −6.792 kcal/mol) with (Z)-octadec-11-enyl acetate and a long-chain oxygenated acetate. These findings indicate potential linkages between multi-omics plasticity and chemosensory gene variation. Furthermore, these computationally prioritized OBPs suggest potential targets for exploring semiochemical-based management tools. Full article

Bactrocera dorsalis (Hendel) is a major fruit-feeding pest that poses a severe and persistent threat to the horticulture industry in tropical and subtropical regions. Methyl eugenol (ME) is a powerful male-specific attractant phytochemical and pheromone precursor that has been widely exploited in lure-and-kill pest management programs. Upon ingestion, ME is metabolized (E)-coniferyl alcohol (E-CF) and 2-allyl-4,5-dimethoxyphenol (DMP), which are stored in the male rectal glands and released during courtship to attract females. Despite its ecological significance, the fundamental molecular mechanism underlying ME perception remains poorly understood. Here, we performed a comparative transcriptomic analysis of ME-responsive and ME-non-responsive male B. dorsalis across four tissues (head, gut, midleg, and wing). A total of 15,727 genes were annotated, of which 970 were associated with odorant-binding proteins (OBPs), odorant receptors (ORs), gustatory receptors (GRs), ionotropic receptors (IRs), and chemosensory proteins (CSPs), as well as detoxification families comprising cytochrome P450s (CYPs), carboxylesterases (CaEs), glutathione S-transferases (GSTs), and uridine diphosphate (UDP)-glycosyltransferases (UGTs), and the stress-related heat shock proteins (HSPs) genes. Differential expression analysis identified 7222, 7763, and 6105 differentially expressed genes (DEGs) in the head, gut, and wings/midlegs, respectively, between ME-responsive and ME-non-responsive males. Notably, CYPs, UGTs, and HSPs involved in detoxification and stress response were significantly downregulated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that CYPs were significantly enriched in metabolic detoxification pathways. These findings reveal a complex molecular interplay between olfaction and detoxification and suggest that ME induces coordinated genetic pathways supporting survival, reproduction, and environmental adaptability. This knowledge provides a foundation for the development of eco-friendly pest management strategies targeting these molecular mechanisms. Full article

The soybean pod borer, Leguminivora glycinivorella, is a monophagous pest that threatens soybean production. Its larvae feed concealed within pods, which limits the efficacy of conventional insecticides. Elucidating its chemosensory system is therefore essential for developing green, behavior-based management strategies. Reference-based transcriptomics across multiple tissues of L. glycinivorella identified a comprehensive repertoire of chemosensory genes, including 76 odorant receptors (ORs), 15 gustatory receptors (GRs), 18 ionotropic receptors (IRs), 52 odorant-binding proteins (OBPs), 18 chemosensory proteins (CSPs), and 4 sensory neuron membrane proteins (SNMPs). Sequence and phylogenetic analyses characterized these candidates within the context of known insect chemosensory families. Notably, canonical bitter GRs and specific IR lineages (e.g., IR100/IR85a) were not detected in our dataset, potentially reflecting adaptation to the specialized soybean-feeding habit of this pest. Expression profiling further revealed pronounced sexual and tissue dimorphism: male antennae showed significant enrichment of putative pheromone receptors (PRs) and LglySNMP1, whereas several OBPs and ORs exhibited female-biased expression, suggesting roles in host location and oviposition. Additionally, the high expression of GR43a homologs points to fructose sensing, while the lack of detectable CO₂ receptor components (except LglyGR2) suggests atypical carbon dioxide perception mechanisms. Collectively, this study provides a valuable expression atlas of chemosensory genes in L. glycinivorella and identifies sex-specific candidate genes for future functional validation and behavior-based pest management. Full article

Echinophora tenuifolia L. subsp. sibthorpiana (E. tenuifolia), Apiaceae, is a traditional medicinal and culinary plant, yet its phytochemical composition and biological activity have not been fully investigated. The aim of the present study was to evaluate the chemical profile of E. tenuifolia aerial parts extract and to assess its effects on healthspan and metabolic regulation in Caenorhabditis elegans (C. elegans). The characterization of the extract by NMR spectroscopy and HPLC-PDA revealed the presence of secondary metabolites, with rutin being the most abundant phenolic compound identified in the extract, alongside the presence of chlorogenic acid, ferulic acid, rosmarinic acid, caffeic acid, p-coumaric acid, and salicylic acid. The extract supplementation enhanced early-life locomotor activity and chemosensory behavior without affecting the lifespan. It also significantly improved thermotolerance and resistance to oxidative stress in C. elegans. Additionally, in a glucose-induced obesity model, the extract reduced lipid accumulation and triglyceride levels and restored glucose-impaired mitochondrial membrane potential. The extract dose-dependently alleviated glucose-induced endoplasmic reticulum and mitochondrial stress by suppressing the expression of both essential chaperones: endoplasmic reticulum chaperone BiP homolog hsp-4 and heat shock protein hsp-6. These findings indicate that E. tenuifolia extract possesses potential beneficial effects on metabolic and mitochondrial health under glucose-induced stress conditions. These observations are likely mediated by the synergistic phenolic composition of the extract, and reveal E. tenuifolia as a promising source of bioactive compounds relevant to aging and preventive strategies for cardiometabolic health. Full article

The Asian migratory locust (Oedaleus decorus asiaticus) is a major grassland pest in northern China, with outbreak dynamics closely linked to phase transition mediated by chemical communication. This study focused on a chemosensory protein, OasiCSP12, to explore its potential role in this process. We analyzed its expression patterns via qRT-PCR, purified the recombinant protein, and identified potential ligands through fluorescence competitive binding assays. Structural insights were gained through homology modeling, molecular docking, and molecular dynamics simulations, with binding energetics assessed using MM/PBSA. Results showed that OasiCSP12 expression is phase- and sex-specific, being significantly upregulated in gregarious adult antennae. The protein bound selectively to 15 locust body-surface volatiles, including aldehydes and esters. Its structure features a hydrophobic binding cavity where van der Waals interactions, primarily predicted to be mediated by residues Val86, Leu71, and Trp101, likely stabilize ligand complexes. These findings indicate that OasiCSP12 is potentially associated with both chemical perception and phase regulation in O. d. asiaticus, providing a candidate target for developing behavior-based green control strategies against this pest. Full article

The Mediterranean fruit fly (Ceratitis capitata) is a globally invasive pest that affects a wide range of fruit and vegetable crops. Identifying cost-effective attractants is essential for sustainable integrated pest management (IPM). This study explored whether molecular docking, combined with electrophysiological recordings, can help prioritize structurally diverse compounds with potential relevance to medfly olfaction. We assessed the predicted interactions of more than 100 attractant-related and semiochemical compounds, including multiple stereoisomers, with 14 odorant-binding proteins (OBPs) and four odorant receptors (ORs). Trimedlure served as a benchmark ligand. Docking suggested that several sesquiterpenes may interact favorably with subsets of OBPs and ORs, although these predictions require biochemical validation. A small set of compounds with high predicted affinity, readily available in the laboratory, was further examined using electroantennography (EAG), which confirmed that selected sesquiterpenes elicited peripheral antennal activation in irradiated males. Overall, our results demonstrate the utility of computational screening as an exploratory tool for prioritizing candidate ligands and generating hypotheses about chemosensory processing in C. capitata. Integrating molecular modeling with biochemical and behavioral validation is a promising approach to developing next-generation IPM attractants. Full article

Odorant-binding proteins (OBPs) and chemosensory proteins (CSPs) serve as carriers for signal molecules within the insect olfactory system, playing a crucial role in detecting chemical cues related to feeding and reproduction. However, their roles in host shift and environmental adaptation remain poorly understood. This study identified the OBP and CSP gene families across 32 Drosophila species, revealing their adaptive evolutionary trajectory. It was found that the gene number of the OBP family varied widely between species, ranging from 37 to 66 genes, while the gene number of the CSP family was conserved. The OBP family experienced two major gene expansion events on the ancestral branches of the diet-diverse melanogaster lineage, leading to an increased number. Positive selection occurred during evolution in the orthologous groups of Obp22a, Obp57e and Obp83ef. Homology modeling and molecular docking revealed that variation in the positively selected sites across different Drosophila species resulted in significant changes to free binding energy and affinity for plant odors and insecticides. Our findings highlight gene expansion and functional diversification within the Drosophila OBP family may contribute to shaping the dietary spectrum and promoting adaptation to toxic substances. Full article

Chemosensory proteins (CSPs) are found in the olfactory sensory organs (antennae and maxillary palps) and/or gustatory sensory organs (labellum and legs) and have long been accepted to function through the binding of odorants. However, the same CSPs are also expressed in many tissues other than olfactory and gustatory organs, such as the gut, brain, fat body, wing, epidermis, Corpora allata, salivary gland, pheromone gland, prothoracic gland, etc. In this report, we suggest renaming the “chemosensory protein (CSP)” the “4-Cysteine Soluble Protein (4CSP)”. This paradigm and nomenclature shift is based on molecular characteristics, genomic mining, tissue distribution, and functional roles beyond those related to olfaction. We examined prior studies on this protein gene family to bolster the renaming, highlighting the most recent findings that we ascribe to “pleiotropic properties” and evolutionary relevance rather than smell. The scope of the report, per se, is broad, and this is especially true given the volume of data that has been gathered on 4CSP expressed in ways that are not consistent with the olfactory paradigm. Statements outlining the many chemosensory properties of 4CSPs, particularly how they activate olfactory receptor neurons (ORNs), are currently scarce, if they exist at all. Many debates currently focus on 4CSPs’ non-chemosensory functions, which are backed by a multitude of evidence, from gene evolution to tissue distribution. Therefore, strong arguments in favor of renaming chemosensory proteins are becoming evident here, outweighing the drawbacks. Full article

Insects rely on their olfactory systems for host finding, mate choice, and oviposition. These odor-guided behaviors are mediated by the peripheral chemosensory system. The solanaceous pests Phthorimaea operculella and Phthorimaea absoluta cause severe damage to solanaceous crops worldwide. In this study, we aimed to elucidate the olfactory molecular mechanisms of these two pests. We first screened and identified odorant-binding proteins (OBPs), chemosensory proteins (CSPs), and sensory neuron membrane proteins (SNMPs) from the genomes of P. operculella and P. absoluta. We then used RNA sequencing to characterize the tissue expression profiles of OBPs, CSPs, and SNMPs in P. operculella across developmental stages and adult chemosensory organs. From P. operculella, 47 OBPs, 26 CSPs, and 2 SNMPs were identified, and from P. absoluta, 39 OBPs, 24 CSPs, and 2 SNMPs were identified. RNA-seq-based expression profiling in P. operculella was used to resolve sex-biased deployment in antennae: DESeq2 analysis (|log₂FC| > 1, FDR < 0.05) identified 24 OBPs and four CSPs with significant sexual dimorphism, with 14 OBPs and four CSPs upregulated in female antennae (FAn) and 10 OBPs and one CSP, together with SNMP2, upregulated in male antennae (MAn). In reproductive tissues (FOv vs. MGe), three OBPs and one CSP were enriched in the female ovipositor (FOv), whereas six OBPs and five CSPs were enriched in male genitalia (MGe), and no SNMPs met the differential-expression threshold. These candidate genes provide molecular entry points for functional studies and for developing behavior-based, environmentally compatible management strategies for P. operculella and P. absoluta. Full article

Olfaction is essential for key insect behaviors, such as host-seeking and mating, and is initiated by odorant-binding proteins (OBPs), which bind and transport hydrophobic odors. Thrips hawaiiensis is a major pest that infests the flowers of numerous horticultural crops, yet its chemosensory mechanisms remain poorly understood. Now, the availability of its genome assembly allows us to address this gap. To this end, we performed a comprehensive exploration and comparative analysis of its OBP genes. Our genome-wide analysis identified a total of 12 OBP genes in T. hawaiiensis, whereas the repertoire across other published thrips genomes ranges from 10 to 17, a count significantly lower than that in most other insects. Notably, transcriptomic and RT-qPCR analyses revealed consistent male-biased expression of OBPs in T. hawaiiensis, supporting their role in mate-finding and foraging behaviors. Furthermore, we identified 11 chemosensory proteins (CSPs). Transcriptomic and RT-qPCR analyses revealed that these CSPs exhibit an expression pattern similar to that of the OBPs, with over half of the genes showing significantly higher expression in males. This work provides a foundational framework for future functional studies of olfactory proteins, both in T. hawaiiensis and the wider insect community. 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 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