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Introduction: The moth species Athetis lepigone (Moschler) (Lepidoptera: Noctuidae), which has recently been identified as a pest of summer maize (Zea mays L.) in China, has demonstrated a rapid proliferation with in the Huang-Huai-Hai Plain region since its initial discovery in Hebei Province in 2005. It has become a prevalent pest of corn crops, and its ability to adapt quickly to its surroundings is currently being investigated. One of the key characteristics of its siphoning mouthparts is not only the feeding apparatus itself but also the chemosensory organs that enable the detection of chemical signals from the surrounding environment. However, there is a lack of comprehensive research on the genes responsible for chemosensory and metabolic mechanisms in the proboscises of male and female A. lepigone adults. Methods: In this study, we utilized transcriptome analysis to identify a total of fifty chemosensory genes from six distinct families, including 19 odorant-binding proteins (OBPs), 22 chemosensory proteins (CSPs), one co-receptor (Orco), six odorant receptors (ORs), four ionotropic receptors (IRs), and two sensory neuron membrane proteins (SNMPs) in the proboscis. Notably, seven OBPs, two CSPs, and one OR were discovered for the first time. Additionally, fourteen genes related to metabolism, including cytochrome P450 (CYPs) and carboxylesterases (CXEs), were also identified. Furthermore, a qualitative analysis was conducted on the relative transcript levels of eight related genes. The expression of 21 annotated chemosensory and metabolic genes was compared between A. lepigone adults and larvae using qRT-PCR, revealing tissue specificity. The majority of genes exhibited predominant expression in the antennae and proboscis during the adult stage, while showing slight expression in the combination of sixth-instar larval head oral appendages (maxilla, labium, and antenna) and pheromone gland-ovipositors of female adults. Results/discussion: Our study points to a new pest control strategies that these newly discovered genes have the potential to serve as targets for enhancing future pest control, including mating disruption and the use of food attractants. And it would be advantageous to ascertain the distribution of chemosensory gene expression and gain insights into the functionalities of these genes, thereby establishing a novel theoretical framework for the advancement of eco-friendly pesticides and efficient pest management strategies in the future. [ABSTRACT FROM AUTHOR]

Simple Summary: Three bark beetle species, Tomicus yunnanensis, T. brevipilosus, and T. minor, are the most economically significant pests of the Yunnan pine in Southwestern China. Chemical and physical communication play key roles in various life activities. In this study, we described the fine structure of the adult mouthparts of these three Tomicus species using scanning and transmission electron microscopy. We identified three types of mandibular shapes, which match with their biomechanical properties, their ability to process food, and their preferred foraging locations on tree trunks. Eleven types of sensilla were discernible, including sensilla basiconica, sensilla twig basiconica, sensilla coeloconica, sensilla chaetica, sensilla trichoidea, and sensilla digitiformia. The function roles of each sensilla type were given based on its distribution and structures, especially on the internal structures such as dendrites and tubular body. Most chemoreceptors occur on the palpal tips. No significant differences among the sexes or species were identified; however, intraspecific variability in the number of sensilla twig basiconica 3 and sensilla digitiformia sensilla was evident. These findings will aid future studies of the feeding niches and reproductive behaviors of Tomicus beetles. Tomicus yunnanensis, T. brevipilosus, and T. minor are the most economically significant pests of Pinus yunnanensis in Southwestern China. Chemical and physical factors play critical roles in diverse biological activities. Here, we describe the fine structure of the adult mouthparts of these three Tomicus species using scanning and transmission electron microscopy. We identified three types of mandibular shapes, which determine their biomechanical properties, their ability to process food, and their preferred foraging locations on tree trunks. Eleven types of sensilla were discernible, including sensilla basiconica (Sb.1–2), sensilla twig basiconica (Stb.1–3), sensilla coeloconica (Sco), sensilla chaetica (Sch.1–2), sensilla trichoidea (Str.1–2), and sensilla digitiformia (Sdi). Each basiconic sensillum occurs on the palpal tips and is innervated by 2–6 dendrites. Sb.1 are gustatory receptors, Sb.2 are olfactory receptors, and the three other sensilla have dual taste and mechanical functions. Sco, Sch, and Str are mechanoreceptors. Sdi are mechanical vibration receptions, given that they are innervated by one dendrite with numerous dendritic branches into the nonporous cuticle. No significant differences among the sexes or species were identified; however, intraspecific variability in the number of Stb.3 and Sdi sensilla was evident. These results will aid future studies of Tomicus beetle behaviors. [ABSTRACT FROM AUTHOR]

Background: Insects rely on chemosensory perception, mainly olfaction, for the location of mates, food sources, and oviposition sites. Plant-released volatile compounds guide herbivorous insects to search for and locate their host plants, further helping them to identify suitable positions for oviposition. The fall armyworm Spodoptera frugiperda (S. frugiperda) was found to invade China in 2019 and has since seriously threatened multiple crops, particularly maize and rice. However, the chemical and molecular mechanisms underlying oviposition preference in this pest are not fully understood. Here, the oviposition preference of S. frugiperda on maize and rice plants was investigated. Results: GC-EAD and GC–MS/MS techniques were used to identify the antennally active volatiles from maize and rice plants. The attraction and oviposition stimulation of identified components to female adults were tested in both laboratory and field settings. The odorant receptors (ORs) on female antennae were expressed in Xenopus oocytes, and their functions evaluated by RNAi. Ten and eleven compounds of maize and rice plants, respectively, were identified to possess electrophysiological activity from headspace volatiles. Among these compounds, (Z)-3-hexenyl-acetate specifically presented in maize volatiles was found to play a critical role in attracting females and stimulating oviposition compared to rice volatiles. Among the cloned ORs on the antennae of both sexes, SfruOR23 with highly female-biased expression mediated the responses of females to (Z)-3-hexenyl-acetate. Knockdown of SfruOR23 using RNAi markedly reduced the electrophysiological response of female antennae and oviposition preference to the compound. Conclusions: (Z)-3-Hexenyl-acetate is a key volatile mediating the host and oviposition preference of S. frugiperda on maize. The olfactory receptor of (Z)-3-hexenyl-acetate was identified to be SfruOR23, which is mainly expressed in the antennae of S. frugiperda. [ABSTRACT FROM AUTHOR]

Simple Summary: Orthaga achatina (Lepidoptera: Pyralidae) is one of the most serious pests of camphor trees. Insect olfaction play a crucial role in identification of host plants and oviposition sites. In this study, we identified the binding affinities of GOBPs to camphor volatiles and sex pheromone components using fluorescence competition binding assays. Moreover, key amino acid residues that bind to plant volatiles were identified in GOBPs using 3-D structure modeling and ligand molecular docking, predicting the interactions between the GOBPs and the host plant volatiles. Overall, OachGOBP2 showed a wider odorant binding spectrum and higher binding capacity than GOBP1. The olfactory system in insects are crucial for recognition of host plants and oviposition sites. General odorant binding proteins (GOBPs) are thought to be involved in detecting odorants released by host plants. Orthaga achatina (Lepidoptera: Pyralidae) is one of the most serious pests of camphor trees, Cinnamomum camphora (L.) Presl, an important urban tree species in southern China. In this study, we study the GOBPs of O. achatina. Firstly, two full-length GOBP genes (OachGOBP1 and OachGOBP2) were successfully cloned according to transcriptome sequencing results, and real-time quantitative PCR measurements showed that both GOBP genes were specifically expressed in the antennae of both sexes, proposing their important roles in olfaction. Then, both GOBP genes were heterologous expressed in Escherichia coli and fluorescence competitive binding assays were conducted. The results showed that OachGOBP1 could bind Farnesol (Ki = 9.49 μM) and Z11-16: OH (Ki = 1.57 μM). OachGOBP2 has a high binding affinity with two camphor plant volatiles (Farnesol, Ki = 7.33 μM; α-Phellandrene, Ki = 8.71 μM) and two sex pheromone components (Z11-16: OAc, Ki = 2.84 μM; Z11-16: OH, Ki = 3.30 μM). These results indicate that OachGOBP1 and OachGOBP2 differ in terms of odorants and other ligands. Furthermore, key amino acid residues that bind to plant volatiles were identified in GOBPs using 3-D structure modeling and ligand molecular docking, predicting the interactions between the GOBPs and the host plant volatiles. [ABSTRACT FROM AUTHOR]

Pachyrhinus yasumatsui Kono et Morimoto is a major pest of Chinese jujube, which is widespread in northern China and causes severe economic losses in the jujube industry. Chemosensory genes play crucial roles in insect behaviors. Currently, little is known about chemosensory genes in P. yasumatsui. In the present study, antennal transcriptomes of female and male adult P. yasumatsui were annotated. In total, 113 genes involved in chemosensory functions were identified, including 41 odorant receptors, 28 odorant-binding proteins, 16 ionotropic receptors, 15 chemosensory proteins, 9 gustatory receptors, and 4 sensory neuron membrane proteins. Subsequently, the phylogenetic analyses of these olfactory-related proteins in P. yasumatsui were conducted using multiple sequence alignment. Furthermore, sex-specific expression levels of 113 genes were analyzed based on fragments per kilobase of transcript per million mapped reads (FPKM). Then, the quantitative real-time PCR (RT-qPCR) was used to quantify gene expression profiles of 28 P. yasumatsui OBPs (PyasOBPs) and 15 CSPs (PyasCSPs). The results revealed that 20 PyasOBPs and 13 PyasCSPs exhibited significantly higher expression in the antennae than in the bodies, suggesting that they might have functions in olfaction. Moreover, some OBPs and CSPs (PyasOBP6 , PyasOBP7 , PyasOBP16 , PyasOBP21 , and PyasCSP4) exhibited female-biased expression, indicating that they might take part in several female-specific behaviors. This study will promote the understanding of olfactory mechanism in P. yasumatsui , and our findings lay the groundwork for developing environmentally friendly pest management measures. [ABSTRACT FROM AUTHOR]

Simple Summary: Trichogramma wasps are minute egg parasitoids that are one of the most used biocontrol agents to manage lepidopteran pests. Given the great success in industrializing a mass-rearing method for the cost-effective production of Trichogramma dendrolimi, this parasitoid wasp has been used extensively to control agricultural and forestry pests in China. So far, while the biology and ecology of T. dendrolimi have been intensively studied to provide successful biological control, the limited genome information constrains the interpretation of the molecular mechanism underlying its host recognition and parasitism. Here, we assembled a high-quality reference genome for T. dendrolimi and identified the repetitive sequences and protein-coding genes. A phylogenomic tree constructed for T. dendrolimi and 24 hymenopteran species places the family Trichogrammatidae sister in the remaining Chalcidoidea species. We found that significantly expanded and contracted gene families are involved in the development, regulation and transport processes in T. dendrolimi, respectively. Additionally, 24 odorant binding proteins, 100 olfactory receptors, 27 gustatory receptors, 27 ionotropic receptors and 87 venom genes were identified in the genome of T. dendrolimi. Our study provides a foundation for future studies on the molecular mechanism underlying host recognition and parasitism in the Trichogramma species. Trichogramma dendrolimi is one of the most successfully industrialized Trichogramma species used to control agricultural and forestry pests in China. However, the molecular mechanisms underlying its host recognition and parasitism remain largely unknown, partially due to the limited genome information of this parasitoid wasp. Here, we present a high-quality de novo assembly of T. dendrolimi through a combination of Illumina and PacBio sequencing technologies. The final assembly had a length of 215.2 Mb and contains 316 scaffolds with a scaffold N50 size of 1.41 Mb. Repetitive sequences with a length of 63.4 Mb and 12,785 protein-coding genes were identified. Significantly expanded gene families were identified to be involved in the development and regulatory processes, while remarkably contracted gene families were involved in the transport processes in T. dendrolimi. The olfactory and venom-associated genes were identified in T. dendrolimi and 24 other hymenopteran species, using uniform methods combining BLAST and HMM profiling. The identified venom genes of T. dendrolimi were enriched in antioxidant activity, tricarboxylic acid cycle, response to oxidative stress and cell redox homeostasis. Our study provides an important resource for comparative genomics and functional studies to interpret the molecular mechanisms underlying host recognition and parasitism of Trichogramma species. [ABSTRACT FROM AUTHOR]

Simple Summary: Reticulitermes chinensis Snyder is an important pest that destroys trees and buildings and causes great damage. The present study investigated the role of RcOrco. A method for preparing large amounts of dsRNA using sonication of engineered bacteria was established. The dsRNA produced using this method was ingested by R. chinensis via feeding, which decreased the expression level of RcOrco and survival rate. The results of this study enhance our knowledge of orco function in social insects and propose new potential targets for termite control. Reticulitermes chinensis Snyder is a serious pest in China, and the odorant receptor co-receptor gene RcOrco plays a crucial role in olfaction. However, the function of RcOrco in the resistance of termites to entomopathogens has not been reported. We constructed dsRcOrco-HT115 engineered bacteria based on the RcOrco sequence from the full-length transcriptome data of R. chinensis. The engineered bacteria expressed dsRNA of RcOrco. Sonication was used to inactivate the dsRNA-HT115 strain and obtain a large amount of dsRcOrco. The dsRcOrco produced using this method overcame the problem that genetically engineered bacteria could not be applied directly and improved its effectiveness against termites. Bioassays using the dsRcOrco generated using this method showed that dsRcOrco significantly increased the toxicity of the bacterial and fungal pathogens to R. chinensis. The present study showed, for the first time, the function of Orco in termite resistance to pathogens, and the results provide a theoretical basis for the development and application of termite RNA biopesticides. [ABSTRACT FROM AUTHOR]

(E)-β-farnesene (EBF) is a typical and ecologically important infochemical in tri-trophic level interactions among plant-aphid-natural enemies. However, the molecular mechanisms by which parasitoids recognize and utilize EBF are unclear. In this study, we functionally characterized 8 AgifOBPs in Aphidifus gifuensis , one dominant endo -parasitoid of wheat aphid as well as peach aphid in China. Among which, AgifOBP6 was the only OBP upregulated by various doses of EBF, and it showed a strong binding affinity to EBF in vitro. The lack of homology between AgifOBP6 and EBF-binding proteins from aphids or from other aphid natural enemies supported that this was a convergent evolution among insects from different orders driven by EBF. Molecular docking of AgifOBP6 with EBF revealed key interacting residues and hydrophobic forces as the main forces. AgifOBP6 is widely expressed among various antennal sensilla. Furthermore, two bioassays indicated that trace EBF may promote the biological control efficiency of A. gifuensis, especially on winged aphids. In summary, this study reveals an OBP (AgifOBP6) that may play a leading role in aphid alarm pheromone detection by parasitoids and offers a new perspective on aphid biological control by using EBF. These results will improve our understanding of tri-trophic level interactions among plant-aphid-natural enemies. • Nanogram level of E-β-farnesene (EBF) significantly increased the parasitism rate of Aphidifus gifuensis especially to winged aphids. • OBP expression showed strong plasticity to EBF, while only AgifOBP6 consistently upregulated to EBF at all doses in A. gifuensis. • AgifOBP6 is expressed commonly in the wasp sensilla, namely placodea, coeloconica, and trichaidea of antennae. • AgifOBP6 displayed a strong binding affinity with EBF and EBF analog mainly due to the hydrophobic interactions. • EBF binding proteins for aphid and its natural enemy, wasp, had evolved independently along convergent involution. [ABSTRACT FROM AUTHOR]

Micromelalopha troglodyta (Graeser) has been one of the most serious pests on poplars in China. We used Illumina HiSeq 2000 sequencing to construct an antennal transcriptome and identify olfactory-related genes. In total, 142 transcripts were identified, including 74 odorant receptors (ORs), 32 odorant-binding proteins (OBPs), 13 chemosensory proteins (CSPs), 20 ionotropic receptors (IRs), and 3 sensory neuron membrane proteins (SNMPs). The genetic relationships were obtained by the phylogenetic tree, and the tissue-specific expression of important olfactory-related genes was determined by quantitative real-time PCR (qRT–PCR). The results showed that most of these genes are abundantly expressed in the antennae and head. In most insects, olfaction plays a key role in foraging, host localization, and searching for mates. Our research lays the foundation for future research on the molecular mechanism of the olfactory system in M. troglodyta. In addition, this study provides a theoretical basis for exploring the relationship between M. troglodyta and their host plants, and for the biological control of M. troglodyta using olfactory receptor as targets. [ABSTRACT FROM AUTHOR]

The woodwasp Sirex noctilio Fabricius is a worldwide quarantine pest for forestry that mainly harms conifers, especially Pinus species. Sirex nitobei Matsumura, a native species from China and closely related to S. noctilio. Olfaction and gustation play a vital role in the life movements of woodwasps, but the molecular mechanisms of chemoperception in these species remain unclear. We performed a comparative analysis of 41 odorant receptors (ORs), 13 ionotropic receptors (IRs), and 8 gustatory receptors (GRs) of S. noctilio and 43 ORs, 16 IRs, and 10 GRs of S. nitobei. Phylogenetic analysis showed that two species-specific OR subfamilies were identified in each species. In addition to conserved "antennal IRs", "divergent IRs", including 7 SnocIRs and 7 SnitIRs, were found. Moreover, a sugar receptor subfamily (SnocGR5 and SnitGR11), a carbon dioxide receptor subfamily (SnocGR2/GR3 and SnitGR3), and a fructose receptor subfamily (SnitGR9) emerged, but bitter receptors were not identified. The tissue-specific expression profiles showed 36 ORs were enriched in the antennae of S. noctilio. Among them, 19 ORs were female-biased, whereas 4 ORs (SnocOR6/15/18/30) were male-biased. In addition, 34 ORs were highly expressed in S. nitobei antennae, of which 22 ORs were female-biased, whereas SnitOR2/18/30 were male-biased. Seven IRs were enriched in the antennae of both species, of which SnocIR4, 6, 10, 11, and 12 were significantly male-biased, while SnitIR4, 6, 10, 11, and 12 were significantly female-biased. Three GRs were highly expressed in the antennae of both species. SnocGR2 and SnocGR6 were also highly expressed in the head and leg, respectively. In the present study, a total 62 and 69 chemosensory receptor genes were identified in the antennal transcriptomes of S. noctilio and S. nitobei, respectively. Although most receptor genes are homologous, there are also some specific receptor genes, suggesting similarities and differences in molecular mechanisms between the two closely related species. OR genes may be involved in different physiological functions by whether they are expressed in olfactory organs, or obvious gender bias. Our results provide a foundation for further investigating the molecular mechanisms of chemoreception in these two closely related woodwasp species, and establishes a starting point for further research on molecular mechanisms of the olfactory system in symphyta woodwasps. [ABSTRACT FROM AUTHOR]

BACKGROUND: Anopheles sinensis is the most widely distributed mosquito species and is the main transmitter of Plasmodium vivax malaria in China. Most previous research has focused on the mechanistic understanding of biological processes in An. sinensis and novel ways of interrupting malaria transmission. However, the development of functional genomics and genetics‐based vector control strategies against An. sinensis remain limited because of insufficient site‐specific genome editing tools. RESULTS: We report the first successful application of the CRISPR/Cas9 mediated knock‐in for highly efficient, site‐specific mutagenesis in An. sinensis. The EGFP marker gene driven by the 3 × P3 promoter was precisely integrated into the odorant receptor co‐receptor (Orco) by direct injections of Cas9 protein, double‐stranded DNA donor, and Orco‐gRNA. We achieved a mutation rate of 3.77%, similar to rates in other mosquito species. Precise knock‐in at the intended locus was confirmed by polymerase chain reaction (PCR) amplification and sequencing. The Orco mutation severely impaired mosquito sensitivity to some odors and their ability to locate and discriminate a human host. CONCLUSION: Orco was confirmed as a key mediator of multiple olfactory‐driven behaviors in the An. sinensis life cycle, highlighting the importance of Orco as a key molecular target for malaria control. The results also demonstrated that CRISPR/Cas9 was a simple and highly efficient genome editing technique for An. sinensis and could be used to develop genetic control tools for this vector. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Simple Summary: Odorant receptors (ORs) play an important role in the olfactory system in insects. However, there is no functional research on the odorant receptors of Galeruca daurica. In this study, 21 OR genes were identified from the transcriptome database of G. daurica adults. Most GdauORs were mainly expressed in antennae, and the expression levels of GdauORs in adults were affected by age. When GdauOR4, GdauOR15, and GdauORco were silenced by RNAi, the electrophysiological responses to host plant volatiles were significantly decreased. Galeruca daurica (Joannis) is an oligophagous pest in the grasslands of Inner Mongolia, China, which feed mainly on Allium spp. Odorant receptors (ORs) play an important role in the olfactory system in insects, and function together with olfactory co-receptor (ORco). In this study, 21 OR genes were identified from the transcriptome database of G. daurica adults, and named GdauOR1-20 and GdauORco. The expression profiles were examined by RT-qPCR and RNA interference (RNAi) and electroantennogram (EAG) experiments were conducted to further identify the olfactory functions of GdauOR4, GdauOR11, GdauOR15, and GdauORco. It was found that 15 GdauORs (OR1, OR3-6, OR8, OR11-13, OR15, OR17-20, and ORco) were mainly expressed in antennae, and the expression levels of GdauORs in adults were affected by age. When GdauOR4, GdauOR15, and GdauORco were silenced by RNAi, the electrophysiological responses to host plant volatiles were significantly decreased in G. daurica. This study lays a necessary foundation for clarifying the mechanism on finding host plants in G. daurica. [ABSTRACT FROM AUTHOR]

BACKGOUND Sex pheromones of the fall armyworm, Spodoptera frugiperda, show differences in composition and proportions in different geographical populations, but always contain Z9‐14:OAc as the major component. Odorant receptor neurons (ORNs) housed in the long trichoid sensilla (TS) of male antennae are essential to detect female‐released sex pheromones in moths. RESULTS: In this study, we identified seven components from pheromone gland extracts of female S. frugiperda in the Yunnan population from China, including (Z)‐7‐dodecen‐1‐yl acetate (Z7‐12:OAc), (Z)‐9‐tetradecenal (Z9‐14:Ald), (Z)‐9‐dodecen‐1‐yl acetate (Z9‐12:OAc), (Z)‐9‐tetradecen‐1‐yl acetate (Z9‐14:OAc), (E)‐11‐tetradecen‐1‐yl acetate (E11‐14:OAc), (Z)‐11‐tetradecen‐1‐yl acetate (Z11‐14:OAc) and (Z)‐11‐hexadecen‐1‐yl acetate (Z11‐16:OAc) at a ratio of 1.2:4:0.8:79.1:1.6:1.6:11.7 by gas chromatography coupled with mass spectrometry. Gas chromatography‐electroantennographic detection showed that Z9‐14:OAc, Z7‐12:OAc and Z11‐16:OAc are the male antennal active components. Peripheral coding of pheromones in males was investigated by single sensillum recording. Five functional neurons housed in three types of TS were identified based on profiles of neuronal responses, which are responsible for attractive component Z9‐14:OAc, synergistic components Z7‐12:OAc, Z11‐16:OAc, interspecific pheromones (Z)‐9‐tetradecen‐1‐ol (Z9‐14:OH) and (Z,E)‐9,12‐tetradecadien‐1‐yl acetate (Z9,E12‐14:OAc), respectively. Wind tunnel and field tests demonstrated that a ternary combination of Z9‐14:OAc, Z7‐12:OAc and Z11‐16:OAc at a ratio of 88:1:11 shows the strongest attractiveness to males. Conclusion: An optimized pheromone blend of Z9‐14:OAc, Z7‐12:OAc and Z11‐16:OAc in an 88:1:11 ratio was identified for monitoring the invasive pest S. frugiperda in China. Five functional ORNs encoding intra‐ and interspecific pheromones were identified in male antennae, of which three neurons encode attractive component Z9‐14:OAc, synergistic components Z7‐12:OAc and Z11‐16:OAc, respectively, and the other two neurons encode interspecific pheromones Z9‐14:OH and Z9,E12‐14:OAc, separately. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Insect olfactory proteins can transmit chemical signals in the environment that serve as the basis for foraging, mate searching, predator avoidance and oviposition selection. Semanotus bifasciatus is an important destructive borer pest, but its olfactory mechanism is not clear. We identified the chemosensory genes of S. bifasciatus in China, then we conducted a phylogenetic analysis of the olfactory genes of S. bifasciatus and other species. And the expression profiles of odorant binding proteins (OBPs) genes in different tissues and different genders of S. bifasciatus were determined by quantitative real-time PCR for the first time. Results: A total of 32 OBPs, 8 chemosensory proteins (CSPs), 71 odorant receptors (ORs), 34 gustatory receptors (GRs), 18 ionotropic receptors (IRs), and 3 sensory neuron membrane proteins (SNMPs) were identified. In the tissue expression analysis of OBP genes, 7 OBPs were higher expressed in antennae, among them, SbifOBP2, SbifOBP3, SbifOBP6, SbifOBP7 and SbifOBP20 were female-biased expression, while SbifOBP1 was male-biased expression and SbifOBP22 was no-biased expression in antennae. In addition, the expressed levels of SbifOBP4, SbifOBP12, SbifOBP15, SbifOBP27 and SbifOBP29 were very poor in the antennae, and SbifOBP4 and SbifOBP29 was abundant in the head or legs, and both of them were male-biased expression. While SbifOBP15 was highly expressed only at the end of the abdomen with its expression level in females three times than males. Other OBPs were expressed not only in antennae but also in various tissues. Conclusion: We identified 166 olfactory genes from S. bifasciatus, and classified these genes into groups and predicted their functions by phylogenetic analysis. The majority of OBPs were antenna-biased expressed, which are involved in odor recognition, sex pheromone detection, and/or host plant volatile detection. However, also some OBPs were detected biased expression in the head, legs or end of the abdomen, indicating that they may function in the different physiological processes in S. bifasciatus. [ABSTRACT FROM AUTHOR]

Simple Summary: In this study, we conducted antennal transcriptome analysis in Glenea cantor (Cerambycidae: Lamiinae) and identified 76 olfactory-related genes, including 29 odorant binding proteins (OBPs), 14 chemosensory proteins (CSPs), 13 odorant receptors (ORs), 18 ionotropic receptors (IRs) and 2 sensory neuron membrane proteins (SNMPs). We also verified the reliability of transcriptome differential genes by qRT-PCR, which indicated the reliability of the transcriptome. Based on the relative expression of 30 d adults, GcanOBP22 and GcanOBP25 were highly expressed not only in the antennae, but also in the wings and legs. In addition, GcanCSP4 was the highest expression on the female antennae at 12 d. These findings laid the foundation for further research on the mechanism of G. cantor olfactory mechanism at the molecular level. Glenea cantor Fabricius (Cerambycidae: Lamiinae) is a pest that devastates urban landscapes and causes ecological loss in southern China and Southeast Asian countries where its main host kapok trees are planted. The olfactory system plays a vital role in mating, foraging, and spawning in G. cantor as an ideal target for pest control. However, the olfactory mechanism of G. cantor is poorly understood at the molecular level. In this study, we first established the antennal transcriptome of G. cantor and identified 76 olfactory-related genes, including 29 odorant binding proteins (OBPs), 14 chemosensory proteins (CSPs), 13 odorant receptors (ORs), 18 ionotropic receptors (IRs) and 2 sensory neuron membrane proteins (SNMPs). Furthermore, the phylogenetic trees of olfactory genes were constructed to study the homology with other species of insects. We also verified the reliability of transcriptome differential genes by qRT-PCR, which indicated the reliability of the transcriptome. Based on the relative expression of 30 d adults, GcanOBP22 and GcanOBP25 were highly expressed not only in the antennae, but also in the wings and legs. In addition, GcanCSP4 was the highest expression on the female antennae at 12 d. These findings laid the foundation for further research on the mechanism of G. cantor olfactory mechanism at the molecular level. [ABSTRACT FROM AUTHOR]

Cotesia ruficrus presents a promising local natural enemy for controlling the invasive fall armyworm Spodoptera frugiperda in China. However, the mechanisms underlying how C. ruficrus locates its target pest remain unclear. In this study, we analyzed the expression patterns of 18 CrufOBPs across different developmental stages of C. ruficrus , and found that CrufOBP1 exhibited consistent and high expression levels in female adults. CrufOBP1 transcript was predominantly localized in sensilla placodea and sensilla trichodea on the antennae. Additionally, we confirmed the binding properties of CrufOBP1 protein to various cuticular compounds of S. frugiperda larvae. Subsequent electroantennogram and behavioral assays revealed that 1-(2-hydroxy-5-methylphenyl)-ethanone attracted female C. ruficrus , consequently increased the parasitism rate. However, upon silencing CrufOBP1 , females exhibited reduced attraction towards 1-(2-hydroxy-5-methylphenyl)-ethanone, indicating the crucial role of CrufOBP1 in the chemoreception of C. ruficrus. These findings shed light on the kairomone-based mechanism employed by C. ruficrus to locate S. frugiperda larvae and hold a promise for the development of environmentally friendly pest management strategies. [Display omitted] [ABSTRACT FROM AUTHOR]

Fried pepper oil (FPO) is a widely used flavoring oil in China, but it suffers from complex chemical reactions that give an unpleasant odor. The aim of this paper is to study the main causes of off-flavor in FPO, as well as identify key off-flavor compounds in FPO. Fifty-eight volatiles were identified using HS-SPME–GC–MS (headspace solid-phase microextraction–gas chromatography–mass spectrometry) during storage. Fifteen off-flavor compounds were initially targeted by odor activity values (OAVs) calculations and partial least squares regression (PLSR) analysis. Eventually, five key off-flavor compounds were identified by recombination experiments and omission test, which were hexanal, (E) - 2-octenal, terpinyl acetate, α -terpineol, and hexanoic acid. The off-flavors could derive from the oxidative degradation of long-chain fatty acids and the acid-catalyzed rearrangement of terpenes. The results of the study provide a theoretical basis for the regulation of off-flavor in FPO and a practical guide for the industrial production of FPO. [Display omitted] • Five odorants with off-flavor have been identified as markers of flavor damage. • Off-flavor of FPO was most related to aldehydes and alcohols. • Oxidative cleavage of long-chain fatty acids could be a main source of off-flavor. • Terpene degradation could be lead to flavor attenuation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Study quality changes in frozen mackerel via multi-omics techniques. • Employed mixed-factor analysis for cooked mackerel's sensory attributes. • PLSR used to link DEPs, DEMs, and mackerel quality. • The prediction of fishiness based on DEPs and DEMs through the use of machine learning. This study employed gas chromatography-mass spectrometry with olfactory (GC–MS–O) and multi-omics methods to investigate the changes in volatile flavor compounds during the freezing process of Pacific chub mackerel (Scomber japonicus) from Japan and China, and Spanish mackerel (Scomberomorus niphonius). A total of 18 volatile flavor compounds were identified, and significant differences in volatile flavor components were observed among samples frozen for 1 week, 1 year, and 2 years. The results of the Partial least squares regression (PLSR) indicated that the fishy odor was correlated with independent variables such as fatty acids (FA 22:4, FA 28:6, FA 24:4), differentially expressed genes (Gene.2425 (NDUFA5), Gene.38 (GPX1), and Gene.2844 (DAD1)). Classification and regression tree (CART) analysis revealed that the peak area values of fatty acids (FA 22:5, FA 20:4) and fatty acid esters of hydroxy fatty acids (FAHFA 18:0/22:3) were the main differentiating factors for fishy odor perception. [ABSTRACT FROM AUTHOR]

Chemosensory genes play important roles in insect behaviors and have thus become potential molecular targets for pest control based on the manipulation of chemoreception-driven behaviors. The great gray weevil Sympiezomias velatus (Chevrolat) (Coleoptera: Curculionidae) is an important agricultural pest that causes serious economic losses to many crops in China, but its chemosensory genes have not been reported. Here we assembled the antennal transcriptomes of female and male adult S. velatus and revealed the major chemosensory genes necessary for olfaction. A total of 138 candidate chemosensory genes in six families were identified, including 41 encoding odorant-binding proteins (OBPs), 11 encoding chemosensory proteins (CSPs), 62 encoding odorant receptors (ORs), 15 encoding gustatory receptors (GRs), six encoding ionotropic receptors (IRs), and three encoding sensory neuron membrane proteins (SNMPs). We analyzed their phylogenetic relationship based on the amino acid sequences of these chemosensory-related protein families in S. velatus and other insects, and the expression profiles based on their antennal transcriptomes. Chemosensory genes that show antenna-abundant/specific or sex-biased expression were observed, suggesting that these genes might have functions in olfaction. Furthermore, we chose an antenna-abundant OBP belonging to ABPX subfamily, SvelOBP15, to investigate its binding property. The results showed that among 33 tested compounds, SvelOBP15 displayed high binding affinities (Ki = 7.36–12.94 μmol/L) with farnesol, nerolidol, limonene and diisobutyl phthalate, indicating that SvelOBP15 plays olfactory roles by binding and transporting specific plant volatiles. These findings will help us better understand the olfactory systems of S. velatus , and provide a basis for functional elucidation of these chemosensory genes. [ABSTRACT FROM AUTHOR]

Iseropus (Gregopimpla) kuwanae Vlereck (Hymenoptera: Ichneumonidae) is an ectoparasitoid wasp that attacks the larvae of Rondotia menciana Moore (Lepidoptera: Bombycidae), which is a major pest harming mulberry trees in China. In this study, we obtained the antennal transcriptome dataset of I. kuwanae using RNA‐Seq technology. A total of 22,090,144 clean reads were generated, and 21,802 unigenes were assembled. Among them, 11,546 (52.96%) unigenes were matched in the NCBI non‐redundant protein database (E‐value of 10−5). Moreover, a total of 9,229 (42.33%) and 5,305 (24.33%) unigenes were annotated by Gene Ontology and Clusters of Orthologous Groups of the proteins database respectively. By antennal transcriptome analysis, a total of 122 candidate chemosensory genes were identified, including 11 odorant‐binding protein (OBP) genes, 6 chemosensory protein (CSP) genes, 87 olfactory receptor (OR) genes (including one odorant co‐receptor, Orco), 16 ionotropic receptor genes and two sensory neuron membrane protein genes. RT‐qPCR assays revealed that seven of the 11 IkuwOBPs were predominantly expressed in the antennae of I. kuwanae adults. IkuwOBP4 was highly expressed in the head. IkuwOBP7 and IkuwOBP8 had higher expression levels in the legs. Interestingly, IkuwOBP6 was significantly expressed in both female antennae and ovipositor. The present findings can provide the basis for the subsequent in‐depth exploration of chemosensory mechanisms in I. kuwanae. [ABSTRACT FROM AUTHOR]

Labs as guide dogs or sniffer dogs in usage have been introduced into China for more than 20 years. These two types of working dogs own blunt or acute olfactory senses, which have been obtained by artificial selection in relatively closed populations. In order to attain stable olfactory attributes and meet use-oriented demands, Chinese breeders keep doing the same artificial selection. Though olfactory behavior is canine genetic behavior, genotypes of OR genes formed by breeding schemes are largely unknown. Here, we characterized 26 SNPs, 2 deletions, and 2 insertions of 7 OR genes between sniffer dogs and guide dogs in order to find out the candidate alleles associated with working specific traits. The results showed that there were candidate functional SNP alleles in one locus that had statistically severely significant differences between the two subpopulations. Furthermore, the levels of polymorphism were not high in all loci and linkage disequilibrium only happened within one OR gene. Hardy–Weinberg equilibrium (HWE) tests showed that there was a higher ratio not in HWE and lower FST within the two working dog populations. We conclude that artificial selection in working capacities has acted on SNP alleles of OR genes in a dog breed and driven the evolution in compliance with people's intentions though the changes are limited in decades of strategic breeding. [ABSTRACT FROM AUTHOR]

The bark beetle, Scolytus schevyrewi (S. schevyrewi) , is an economically important pest in China that causes serious damage to the fruit industry, particularly, in Xinjiang Province. Chemical signals play an important role in the behavior of most insects, accordingly, ecofriendly traps can be used to monitor and control the target pests in agriculture. In order to lay a foundation for future research on chemical communication mechanisms at the molecular level, we generate antennal transcriptome databases for male and female S. schevyrewi using RNA sequencing (RNA-seq) analysis. By assembling and analyzing the adult male and female antennal transcriptomes, we identified 47 odorant receptors (ORs), 22 ionotropic receptors (IRs), 22 odorant-binding proteins (OBPs), and 11 chemosensory proteins (CSPs). Furthermore, expression levels of all the candidate OBPs and CSPs were validated in different tissues of male and female adults by semiquantitative reverse transcription PCR (RT-PCR). ScosOBP2 and ScosOBP18 were highly expressed in female antennae. ScosCSP2, ScosCSP3 , and ScosCSP5 were specifically expressed in the antennae of both males and females. These results provide new potential molecular targets to inform and improve future management strategies of S. schevyrewi. [ABSTRACT FROM AUTHOR]

Endoclita signifier Walker (Lepidoptera: Hepialidae), a polyphagous insect, has become a new wood-boring pest in Eucalyptus plantations in southern China since 2007, which represents a typical example of native insect adaptation to an exotic host. After the third instar, larvae move from soil to standing trees and damage the plants with a wormhole. Although females disperse to lay eggs, larvae can accurately find eucalyptus in a mingled forest of eight species, which leads us to hypothesize that the larval olfactory system contributes to its host selection. Herein, we investigated the transcriptomes of the head and tegument of E. signifer larvae and explored the expression profiles of olfactory proteins. We identified 15 odorant-binding proteins (OBPs), including seven general OBPs (GOPBs), six chemosensory proteins (CSPs), two odorant receptors (ORs), one gustatory receptor (GR), 14 ionotropic receptors (IRs), and one sensory neuron membrane protein (SNMP). Expression profiles indicated that all olfactory proteins, except for EsigCSP1, were expressed in the head, and most were also detected in non-olfactory tissues, especially thorax tegument. Furthermore, EsigOBP2, EsigOBP8, EsigGOBP1, EsigGOBP2, EsigGOBP5, EsigCSP3, EsigCSP5, and EsigOR1 were expressed most strongly in the head; moreover, EsigCSP3 expressed abundantly in the head. EsigGR1 exhibited the highest expression among all tissues. Besides phylogenetic analysis shows that EsigGOBP7 probably is the pheromone-binding protein (PBP) of E. signifier. This study provides the molecular basis for future study of chemosensation in E. signifier larvae. EsigCSP3 and EsigGR1, which have unique expression patterns, might be factors that govern the host choice of larvae and worth further exploration. [ABSTRACT FROM AUTHOR]

The mandarin fish, Siniperca chuatsi , is an economically important perciform species with widespread aquaculture practices in China. Its special feeding habit, acceptance of only live prey fishes, contributes to its delicious meat. However, little is currently known about related genetic mechanisms. Here, we performed whole-genome sequencing and assembled a 758.78 Mb genome assembly of the mandarin fish, with the scaffold and contig N50 values reaching 2.64 Mb and 46.11 Kb, respectively. Approximately 92.8% of the scaffolds were ordered onto 24 chromosomes (Chrs) with the assistance of a previously established genetic linkage map. The chromosome-level genome contained 19,904 protein-coding genes, of which 19,059 (95.75%) genes were functionally annotated. The special feeding behavior of mandarin fish could be attributable to the interaction of a variety of sense organs (such as vision, smell, and endocrine organs). Through comparative genomics analysis, some interesting results were found. For example, olfactory receptor (OR) genes (especially the beta and delta types) underwent a significant expansion, and endocrinology/vision related npy , spexin , and opsin genes presented various functional mutations. These may contribute to the special feeding habit of the mandarin fish by strengthening the olfactory and visual systems. Meanwhile, previously identified sex-related genes and quantitative trait locis (QTLs) were localized on the Chr14 and Chr17, respectively. 155 toxin proteins were predicted from mandarin fish genome. In summary, the high-quality genome assembly of the mandarin fish provides novel insights into the feeding habit of live prey and offers a valuable genetic resource for the quality improvement of this freshwater fish. [ABSTRACT FROM AUTHOR]

Sex pheromones serve a critical role in Lepidopterans finding mates. Male moths perceive and react to sex pheromones emitted by conspecific females through a delicate pheromone communication system. Pheromone receptors (PRs) are the key sensory elements at the beginning of that process. The codling moth (Cydia pomnonella) is an important pome fruit pest globally and a serious invasive species in China. Pheromone‐based techniques have been used successfully in monitoring and controlling this species. We conducted ribonucleic acid sequencing analysis of the codling moth antennal transcriptome and identified 66 odorant receptors (ORs) in a population from Xinjiang province, China, of which 14 were PRs, including two novel PRs (CpomOR2e and CpomOR73). Four PRs that contain full‐length open reading frames (CpomOR1, OR2a, OR5, OR7) and four PRs with ligands that have not been reported previously (CpomOR1, OR2a, OR5, OR7) were selected to deorphanize in the heterologous Xenopus oocyte expression system. Specifically, we found that CpomOR2a and CpomOR5 responded to (E,E)‐8, 10‐dodecadien‐1‐yl acetate (codlemone acetate). Furthermore, CpomOR5 (EC50 = 1.379 × 10−8 mol/L) was much more sensitive to codlemone acetate than CpomOR2a (EC50 = 1.663 × 10−6 mol/L). Since codlemone acetate is an important component of C. pomonella sex pheromone, our results improve the current understanding of pheromone communication in codling moths and will be helpful for the development of pest management strategies. [ABSTRACT FROM AUTHOR]

To determine the key odorants of a popular Chinses rice wine, Shaoxing-jiu, volatile compounds were analyzed by using sensory-directed flavor approaches, including gas chromatography-mass spectrometry (GC-MS), gas chromatography-flame photometric detector (FPD), gas chromatography olfactometry (GC-O), aroma recombination and omission experiments, and odorant addition experiments. Fifty-five volatile compounds were detected in traditional Shaoxing-jiu via GC-MS, more than those in mechanical Shaoxing-jiu. Thirty-four aroma-active compounds in traditional Shaoxing-jiu were determined via GC-O. According to aroma recombination and omission experiments, the aroma profile of the recombination model constructed by these aroma-active compounds at their detected concentrations was similar to that of traditional Shaoxing-jiu, and 15 of them were affirmed as key odorants. Among the key odorants, phenylethyl alcohol, furfural, γ-nonalactone and dimethyl trisulfide presented very highly significant aroma contributions, indicating that their omission would cause great aroma differences. Then odorant addition experiments highlighted the aroma impacts of these four paramount key odorants on sensory descriptors in traditional Shaoxing-jiu. [ABSTRACT FROM AUTHOR]

Background: The woodwasp Sirex noctilio Fabricius is a major quarantine pest worldwide that was first discovered in China in 2013 and mainly harms Pinus sylvestris var. mongolica Litv.. S. nitobei Matsumura is a native species in China and is closely related to S. noctilio. Recently, the two woodwasps species were found attacking the P. sylvestris var. mongolica Litv in succession. The olfactory system is the foundation of insect behavior. Olfactory genes were identified through antennal transcriptome analysis. The expression profiles odorant binding proteins (OBPs) were analyzed with RT-qPCR. Results: From our transcriptome analysis, 16 OBPs, 7 chemosensory proteins (CSPs), 41 odorant receptors (ORs), 8 gustatory receptors (GRs), 13 ionotropic receptors (IRs), and one sensory neuron membrane protein (SNMP) were identified in S. noctilio, while 15 OBPs, 6 CSPs, 43 ORs, 10 GRs, 16 IRs, and 1 SNMP were identified in S. nitobei. Most of the olfactory genes identified in two species were homologous. However, some species-specific olfactory genes were identified from the antennal transcriptomes, including SnocOBP13, SnocCSP6, SnocOR26, SnocGR2, SnocIR7 in S. noctilio and SnitGR9, SnitGR11, SnitIR17 in S. nitobei. In total, 14 OBPs were expressed primarily in the antennae. SnocOBP9 and SnitOBP9, identified as PBP homologues, were sex-biased expression in two siricid, but with different pattern. SnocOBP11 and SnitOBP11 were highly expressed in antennae and clearly expressed in external genitalia. SnocOBP7 and SnitOBP7 were highly expressed in male genitalia. SnocOBP3 and SnocOBP10 were highly expressed in female genitalia and male heads, while SnitOBP3 and SnitOBP10 did not show obvious tissue bias. Conclusion: We analyzed 86 and 91 olfactory genes from S. noctilio and S. nitobei, respectively. Most of the olfactory genes identified were homologous, but also some species-specific olfactory genes were identified, which indicated the similarities and differences of the molecular mechanisms between the two closely-related species. Different expression in the antennae, external genitals or heads, exhibiting an obvious sex bias, suggested their different role in recognizing sex pheromones or plant volatiles. Species-specific expression for several OBPs genes may suggest that they strengthened or lost their original function during species differentiation, resulting in olfactory differences between the two species. [ABSTRACT FROM AUTHOR]

Jasminum sambac is a flower and usually used in food, cosmetics or other chemical industries for its unique flavour characteristics in China. However, molecular sensory technologies have not applied to identify aroma‐active compounds in J sambac concrete. In this study, gas chromatography‐olfactometry (GC‐O), gas chromatography‐mass spectrometry and solvent‐assisted flavour evaporation were applied to isolate the odorants in three Chinese J sambac concrete (E1, E2 and E3) obtained from different companies. A total of forty‐nine, forty‐eight, thirty‐nine odorants were screened by GC‐O with aroma extract dilution analysis in E1, E2 and E3, respectively. The higher flavour dilution (FD) factors were linalool (19 683‐59 049, floral), methyl anthranilate (6561‐19 683, grape‐like) and benzyl acetate (2187‐19 683, floral). Twenty‐two aroma compounds were quantitated by gas chromatography‐flame ionization detection with internal standard, and then their odour activity values were obtained. Linalool, cis‐3‐hexenyl acetate, linalyl acetate, eugenol and methyl salicylate contributed greatly to the aroma of J sambac concretes. The aroma recombination model was established by mixing twenty‐two key odorants based on their measured concentrations, and the result revealed that the overall aroma profile was similar to that of the original sample. These results proved basic data for improvement of the national standard of jasmine concrete. [ABSTRACT FROM AUTHOR]

The predatory insect Arma chinensis (Hemiptera: Pentatomidae) is widely distributed in China, where it is also used to control many agricultural and forest pests. The chemosensory genes expressed in its antennae play crucial roles in food-seeking and mating behaviors. To better understand the olfaction of A. chinensis antennae, we identified the genes related to food-seeking and mating. Sequencing of the antennal transcriptomes of full and hungry male and female A. chinensis revealed 38 odorant-binding proteins (OBPs), 1 chemosensory protein (CSP), 1 Niemann–Pick C2 protein (NPC2), 3 odorant receptors (ORs), 12 ionotropic receptors (IRs), 2 gustatory receptors (GRs), and 3 sensory neuron membrane proteins (SNMPs). These results were used to construct phylogenetic trees. A quantitative real-time PCR (qRT-PCR) analysis showed that the relative transcript levels of AchiGR1 , AchiGR2 , and AchiOBP28 were higher in female than in male antennae in both full and hungry insects, but that the expression of AchiOBP13 and AchiOBP16 was higher only in full A. chinensis females. Thus, the latter genes may encode proteins involved in oviposition selection behavior. AchiGRs (1 and 2), AchiIR6 , and AchiOBPs (6–8 , 12 , 20–22 , 28 , and 34) were highly expressed only in the antennae of full males, indicating the participation of these genes in mate-searching or male pheromone recognition. The expression of AchiOBP31 in the antennae of starved males, AchiOBPs (15 , 18 , and 29) in the antennae of starved females, and AchiOBPs (3 , 4 , and 24) in the antennae of starved males and females suggested that these genes encode food-seeking functions. Our identification of chemosensory genes in A. chinensis antennae and their differential expression in full and hungry insects provides the basis for further functional studies on the chemoreception system of A. chinensis and the sex hormones of predatory insects. [ABSTRACT FROM AUTHOR]

Studies of chemosensory genes are key to a better understanding of intra- and interspecific communications between insects and their environment and provide opportunities for developing environmentally friendly pesticides to target pest species. The bamboo locust Ceracris kiangsu Tsai (Orthoptera: Acrididae) is one of the most important bamboo leaf-eating insects in southern China. However, the genes underlying olfactory sensation are lacking in the bamboo locust. In this study, the transcriptomes of male and female C. kiangsu antennae were sequenced and analyzed. A total of 125 chemosensory genes, including 91 odorant receptors (ORs), 13 ionotropic receptors (IRs), 13 odorant-binding proteins (OBPs), six chemosensory proteins (CSPs), and two sensory neuron membrane proteins, were identified based on sequence alignment and phylogenetic analyses. The expression patterns of all candidate genes on the antennae of males and females, maxillary palps, tarsi, wings, and thoraxes-abdomens were confirmed by real-time quantitative PCR. The analyses demonstrated that most genes are highly expressed in the antennae, and 35 ORs, 7 IRs, 10 OBPs, and 1 CSP exhibit significantly male-biased expression patterns, indicating their potential functions in mating behavior and the recognition of female sex pheromones. In addition to the antennal-predominant genes, some were abundant in the maxillary palps and some in the non-olfactory tissues, suggesting their different functions in the olfactory system of C. kiangsu. Our research offers an extensive resource for investigating the chemoreception mechanism of C. kiangsu. Further studies of olfactory function will provide comprehensive methods and original strategies for integrated pest management. [ABSTRACT FROM AUTHOR]

BACKGROUND Thrips, Megalurothrips usitatus, usually display aggregation behavior, which is probably mediated by a male‐produced aggregation pheromone. Aggregation pheromones are species‐specific, and can be used to develop commercial lures for monitoring and mass‐trapping of pests. The active components of the aggregation pheromone for four thrips species have been identified. However, the components of M. usitatus‐produced aggregation pheromone are still not clear. RESULT: Y‐tube olfactometer assays showed that both male and virgin female M. usitatus were significantly attracted to male but not female volatiles. This was additionally supported by electroantennogram (EAG) assays. Coupled gas chromatography‐electroantennogram detection (GC‐EAD) showed that one component of male‐specific odors elicited a significant electrophysiological response. This compound was characterized as (2E,6E)‐farnesyl acetate, which is structurally different from the active components of the aggregation pheromones of other reported thrips species. Electroantennal responses of M. usitatus increased with increasing doses of synthetic (2E,6E)‐farnesyl acetate. Additionally, this compound significantly attracted adults in laboratory behavioral bioassays. Under field conditions, sticky traps with synthetic (2E,6E)‐farnesyl acetate caught 1.5‐7‐fold more M. usitatus than controls, and this effect of the compound at a dose of 60 μg lasted at least 6 days. CONCLUSION: (2E,6E)‐Farnesyl acetate was identified as the male‐produced aggregation pheromone of M. usitatus. It could attract this thrips species under laboratory and field conditions, suggesting considerable potential as a commercial application to control M. usitatus populations. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Insect olfaction and vision play important roles in survival and reproduction. Diurnal butterflies mainly rely on visual cues whereas nocturnal moths rely on olfactory signals to locate external resources. Histia rhodope Cramer (Lepidoptera: Zygaenidae) is an important pest of the landscape tree Bischofia polycarpa in China and other Southeast Asian regions. As a diurnal moth, H. rhodope represents a suitable model for studying the evolutionary shift from olfactory to visual communication. However, only a few chemosensory soluble proteins have been characterized and information on H. rhodope chemoreceptor genes is currently lacking. In this study, we identified 45 odorant receptors (ORs), nine ionotropic receptors (IRs), eight gustatory receptors (GRs) and two sensory neuron membrane proteins (SNMPs) from our previously acquired H. rhodope antennal transcriptomic data. The number of chemoreceptors of H. rhodope was less compared with that found in many nocturnal moths. Some specific chemoreceptors such as OR co-receptor (ORco), ionotropic receptors co-receptor, CO2 receptors, sugar receptors and bitter receptors were predicted by phylogenetic analysis. Notably, two candidate pheromone receptors (PRs) were identified within a novel PR lineage. qRT-PCR results showed that almost all tested genes (22/24) were predominantly expressed in antennae, indicating that they may be important in olfactory function. Among these antennae-enriched genes, six ORs, five IRs and two GRs displayed female-biased expression, while two ORs displayed male-biased expression. Additionally, HrhoIR75q.2 and HrhoGR67 were more highly expressed in heads and legs. This study enriches the olfactory gene inventory of H. rhodope and provides the foundation for further research of the chemoreception mechanism in diurnal moths. [ABSTRACT FROM AUTHOR]

Despite intense interest in bees, no genomes are available for the bee family Colletidae. Colletes gigas , one of the largest species of the genus Colletes in the world, is an ideal candidate to fill this gap. Endemic to China, C. gigas has been the focus of studies on its nesting biology and pollination of the economically important oil tree Camellia oleifera , which is chemically defended. To enable deeper study of its biology, we sequenced the whole genome of C. gigas using single-molecule real-time sequencing on the Pacific Bioscience Sequel platform. In total, 40.58 G (150×) of long reads were generated and the final assembly of 326 scaffolds was 273.06 Mb with a N50 length of 8.11 Mb, which captured 94.4% complete Benchmarking Universal Single-Copy Orthologs. We predicted 11,016 protein-coding genes, of which 98.50% and 84.75% were supported by protein- and transcriptome-based evidence, respectively. In addition, we identified 26.27% of repeats and 870 noncoding RNAs. The bee phylogeny with this newly sequenced colletid genome is consistent with available results, supporting Colletidae as sister to Halictidae when Stenotritidae is not included. Gene family evolution analyses identified 9,069 gene families, of which 70 experienced significant expansions (33 families) or contractions (37 families), and it appears that olfactory receptors and carboxylesterase may be involved in specializing on and detoxifying Ca. oleifera pollen. Our high-quality draft genome for C. gigas lays the foundation for insights on the biology and behavior of this species, including its evolutionary history, nesting biology, and interactions with the plant Ca. oleifera. [ABSTRACT FROM AUTHOR]

BACKGROUND: The Apolygus lucorum is one of the most destructive insect pests in China with a wide range of host plants. Interaction of A. lucorum with surrounding environment heavily relies on chemical communication. Deorphanization of receptors involved in odors detection elevates our understanding of the olfactory system of this pest and may help to develop a chemical ecology‐based control strategy. RESULTS: AlucOR80, an odorant receptor (OR) in A. lucorum was newly cloned. Gene expression analysis showed that this receptor was mainly expressed in the antennae and head of both sexes but with a male bias. The Xenopus oocytes heterologous expression system coupled with the two‐electrode voltage‐clamp (TEVC) recording revealed that AlucOR80 was tuned to 21 selected compounds. Furthermore, electroantennogram (EAG) tests confirmed that all 21 ligands of AlucOR80 were electrophysiologically active in antennae of both sexes. Behavioral trials in a three‐cage olfactometer indicated that 16 compounds were behaviorally active, amongst which, 12 components were attractants and four components were repellents for adults of both sexes. Butyl butyrate and Dimethyl disulfide (DMDS) were the strongest attractive and repellant compounds, respectively. Importantly, we found the repellency of 1, 8‐Cineole, S‐(−)‐cis‐Verbenol and (1S)–(1)‐beta‐Pinene against adults of A. lucorum. CONCLUSION: Although AlucOR80 is a general OR, may play important role in the olfactory perception of A. lucorum. Screening of AlucOR80 ligands by behavioral assay provided valuable insights by which olfactory‐based management approaches could be developed by utilizing the behaviorally active components as attractants or repellents. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Background: The tiny casebearer moth Coleophora obducta, an important defoliator of Larix spp., is a major threat to ecological security in north China. Studies have shown that C. obducta is strongly specific to host plants; it is unable complete its life cycle without Larix spp. The sex pheromones of C. obducta Z5-10:OH have been elucidated; and eight types of antennae sensilla, have been detected, indicating that an exploration of its olfactory proteins is necessary, due to the general lack of information on this topic. Methods: We investigated the whole body transcriptome of C. obducta, performed a phylogenetic analysis of its olfactory proteins and produced expression profiles of three pheromone-binding proteins (CobdPBPs) by qRT–PCR. Results: We identified 16 odorant binding proteins, 14 chemosensory proteins, three sensory neuron membrane proteins, six odorant degrading enzymes, five antennal esterases, 13 odorant receptors, seven ionotropic receptors and 10 gustatory receptors, including three PBPs and one odorant co-receptor. Additionally, three putative pheromone receptors, two bitter gustatory receptors and five functional ionotropic receptors were found by phylogenetic analysis. The expression profiles of three PBPs in males and females showed that all of them exhibited male-specific expression and two were expressed at significantly higher levels in males. These data provide a molecular foundation from which to explore the olfactory recognition process and may be useful in the development of a new integrated pest management strategy targeting olfactory recognition of C. obducta. [ABSTRACT FROM AUTHOR]

Chemosensory proteins (CSPs) are thought to play roles in the insect olfactory system by binding and carrying hydrophobic odorants across the aqueous sensillar lymph. The band-winged grasshopper, Oedaleus asiaticus Bei-Bienko, is one of the most important grasshopper pests in northern China, but there is little information about its olfactory system. In order to investigate the olfactory functions of CSPs in this pest, three CSP genes (OasiCSP4, OasiCSP11 and OasiCSP12) were expressed in Escherichia coli, and the binding affinities of the three recombinant CSP proteins were measured for 16 volatiles from the host plant (Stipa krylovii), fecal material and body of live adult O. asiaticus using fluorescence competitive binding assays. To further verify their olfactory functions, RNA interference (RNAi) and electrophysiological recording were conducted. The three recombinant proteins displayed different degrees of binding to various volatiles in ligand-binding assays, with OasiCSP12 having higher binding affinities for more volatiles than OasiCSP4 and OasiCSP11. OasiCSP12 exhibited strong binding affinities (Ki < 20 μΜ) for five host plant volatiles and one volatile from the live body of adult O. asiaticus. The transcript levels of the three OasiCSP genes were significantly lower after silencing the individual genes by RNAi, which in turn reduced the EAG responses in adults of both sexes to most tested compounds. Our study indicates that these three OasiCSPs are involved in the detection of volatile semiochemicals, and may play important roles in finding host plants and in aggregation in O. asiaticus. [ABSTRACT FROM AUTHOR]

The chive midge, Bradysia odoriphaga , is a major insect pest affecting Chinese chive production in China. Its adult life stage is nonfeeding and has a short life span. Hence, the perception of chemical stimuli is important for its adult behavior and reproductive success. To better understand its chemosensory process at the molecular level, chemosensory receptor genes were identified based on transcriptomes of B. odoriphaga. In total, 101 chemosensory genes were identified from the antenna and body transcriptomes, including 71 odorant receptors (ORs), 18 ionotropic receptors (IRs), 5 gustatory receptors (GRs), and 7 sensory neuron membrane proteins (SNMPs). Phylogenetic analysis indicated that most of these genes have homologs among other Dipteran insects. A transcript abundance comparison based on FPKM values was conducted to analyze the sex- and tissue-specific expression profiles of these chemosensory genes. Moreover, quantitative real-time PCR of OR transcripts was performed on different tissues (female antennae, male antennae, heads, and legs) to verify the transcriptional expression levels of ORs in the transcriptomes. This analysis suggested that 44 ORs showed significantly higher expression in the female antennae, while 16 OR transcripts were most highly expressed in the male antennae and may play significant roles in sex pheromone detection. In addition, some IRs and GRs might be involved in CO2 and sugar detection and temperature sensing. In the present study, 101 chemosensory genes were identified, and their putative functions were predicted. This work could provide a basis to facilitate functional clarification of these chemosensory genes at the molecular level. [ABSTRACT FROM AUTHOR]

Recent studies have suggested that insulinoma-associated protein 1 (INSM1) is a useful marker for pathological diagnosis of neuroendocrine tumors. In the present study, we investigated the association between INSM1 expression and prognosis in patients with olfactory neuroblastoma (ONB) and assessed the usefulness of INSM1 as a prognostic biomarker in these patients. Immunohistochemistry was performed on 109 ONB patients who underwent endoscopic surgery at Beijing Tong Ren Hospital (Beijing, China) between June 2006 and November 2021 Patient age at the time of surgery ranged from 10 months to 72 years (mean age, 43.55 ± 13.47 years). In total, 63 (57.8%) and 46 (42.2%) tumors occurred in male and female patients, respectively. The percentages of grade I–IV cases were 13.8% (15/109), 36.7% (40/109), 29.4% (32/109) and 20.2% (22/109), respectively. The expression rate (moderately/strongly positive) of INSM1 was significantly higher in high-grade (Ⅲ/Ⅳ; 83%; 45/54) than low-grade (Ⅰ/Ⅱ; 27%; 15/55) ONB cases. High expression levels of INSM1 were significantly positively associated with high pathological stage (p < 0.001), local recurrence, and death. Kaplan‑Meier analysis revealed that patients with high INSM1 expression had significantly shorter disease‑free survival (DFS) and mean survival (75.01 ± 10.71 vs. 158.56 ± 10.32) times, and shorter overall survival (OS). Multivariate Cox regression analysis revealed that INSM1 was an independent prognostic factor for DFS (HR: 4.963, 95%CI [2.11–10.84] p < 0.001) and OS (HR: 4.791, 95%CI [2.117–10.485], p < 0.001) after adjusting for sex, age, and tumor grade. In addition, INSM1 was an independent prognostic factor for DFS in patients treated with surgery (HR: 3.714, 95%CI [1.267–10.889], p = 0.017) and chemotherapy (HR: 5.574, 95%CI [1.584–19.612], p = 0.007). INSM1 expression had a positive association with the prognosis of patients with ONB and could serve as a prognostic biomarker in these patients. [ABSTRACT FROM AUTHOR]

Holotrichia oblita is one of the nastiest pests in China. In present research, four full-length cDNA encoding of HoblOBP genes were cloned and sequenced from H. oblita. The mRNA of HoblOBPs were predominantly expressed in antenna. The recombinant HoblOBPs proteins were obtained for fluorescence binding assays. Four of HoblOBPs could mediate the response of H. oblita to organic fertilizers-derived attractants, including HoblOBP5 binding to skatole; HoblOBP8 binding to p-cresol, indole and skatole; HoblOBP9 binding to indole and 4-allylanisole; and HoblOBP24 binding to p-cresol, indole and 4-ethylphenol. Further, RNA interference demonstrated that transcripts of HoblOBP5 , 8 , 9 , and 24 decreased in a time-dependent manner after dsRNA-injection. Knockdown of HoblOBP5 , 8 , 9 , and 24 by injection of dsRNA successfully interfered with behavioral responses towards the target compounds in beetles. Our results showed that HoblOBP5, HoblOBP8, HoblOBP9 and HoblOBP24 are essential in mediating the approach behavior of H. oblita. • Six recombinant HoblOBPs from Holotrichia oblita was expressed and purified. • HoblOBP5 , 8 , 9 , and 24 showed high binding affinity to five compounds. • RNA interference demonstrated that HoblOBP5 , 8 , 9 , and 24 are essential in mediating the approach behavior of H. oblita. [ABSTRACT FROM AUTHOR]

Southern rice black-streaked dwarf virus, transmitted by the white-backed planthopper (Sogatella furcifera [Horváth]) (Hemiptera: Delphacidae) was first found in Guangdong Province, China. A previous study has demonstrated that the host plant preferences of S. furcifera are altered by infection with the virus, with virus-free S. furcifera preferring virus-infected rice plants over healthy rice plants, whereas viruliferous S. furcifera prefer uninfected plants. To test the hypothesis that odorant-binding proteins (OBPs) are involved in the preference of S. furcifera for virus-infected rice plants, we first compared the expression levels of SfurOBP2 and SfurOBP11 in virus-free and viruliferous S. furcifera. The results show that mRNA transcript of these 2 genes were significantly reduced in viruliferous S. furcifera. We then used RNAi-mediated gene silencing to confirm the function of these 2 odorant-binding proteins in host selection of S. furcifera. The results showed that silencing of the SfurOBP2 gene caused virus-free S. furcifera to no longer prefer virus-infected rice plants over uninfected rice plants, but the ability to locate host plants was maintained. These results indicate that SfurOBP2 appears to play a crucial role in the preference of S. furcifera for virus-infected rice plants. [ABSTRACT FROM AUTHOR]

The band-winged grasshopper Oedaleus asiaticus (Orthoptera: Acridoidea) is an important insect pest in north China. Chemosensory membrane proteins are believed to be crucial factors in direct interactions with odorants in the chemosensory process. However, there is much limited information on the chemosensory system in this pest. In this study, a total of 69 candidate chemosensory membrane protein genes, including 60 olfactory receptors (ORs), 6 ionotropic receptors (IRs) and 3 sensory neuron membrane proteins (SNMPs), were identified for the first time from the antennal transcriptomes of O. asiaticus. Blastp match and phylogenetic analysis demonstrated that these chemosensory membrane proteins were the closest to their orthologous species, Locusta migratoria. The qRT-PCR analysis revealed that all tested 14 OR and two SNMP genes (OasiSNMP1 and OasiSNMP2a) were strongly expressed in adult antennae, and nearly all tested genes (15/16) displayed significant differences in the expression levels between both sexes. Moreover, two IR genes (OasiIR25a and OasiIR76b) had uniquely high expression levels in the antennae, labial palps and maxillary palps, while three IR genes (OasiIR1 , OasiIR2 and OasiIR3) were highly expressed in most tested tissues (heads without antennae and mouthparts, labial palps, maxillary palps, labia without labial palps, thoraxes, tarsi, and abdomens) except for antennae, labra, and wings but OasiIR5a was just faintly expressed in the antennae, labia without labial palps, labial palps, maxillary palps and abdomen. Our results provide important molecular information for further investigation on the chemoreception mechanisms in O. asiaticus. Unlabelled Image [ABSTRACT FROM AUTHOR]

Highlights • Three a alleles and three b alleles in U. esculenta were cloned so far. • The a locus encodes 2 pheromones and a receptor, with a structural variant a3 allele. • The a locus is responsible for the conjugation formation and cells fusion. • The b locus is essential for hyphal growth and pathogenicity. • A solopathogenic strain UeTSP could trigger hyphal growth and infection. Abstract Ustilago esculenta is closely related to the smut fungus Ustilago maydis and, in an endophytic-like life in the plant Zizania latifolia , only infects host stems and causes swollen stems to form edible galls called Jiaobai in China. In order to study its different modes of invasion and sites of symptom development from other smut fungi at the molecular level, we first characterized the a and b mating-type loci of U. esculenta. The a loci contained three a mating-type alleles, encoding two pheromones and one pheromone receptor per allele. The pheromone/receptor system controlled the conjugation formation, the initial step of mating, in which each pheromone was specific for recognition by only one mating partner. In addition, there are at least three b alleles identified in U. esculenta , encoding two subunits of heterodimeric homeodomain transcription factors bE and bW, responsible for hyphal growth and invasiveness. Hyphal formation, elongation and invasion after mating of two compatible partners occurred, only when a heterodimer complex was formed by the bE and bW proteins derived from different alleles. We also demonstrated that even with only one paired pheromone-pheromone receptor, the active b locus heterodimer triggered hyphal growth and infection. [ABSTRACT FROM AUTHOR]

Abstract Clostera restitura Walker (Lepidoptera: Notodontidae) is one of the most destructive defoliators of poplars in China. We constructed an antennal transcriptome using Illumina Hiseq 2500™ sequencing and characterized the expression profiles of odorant binding proteins for better understanding of the olfactory receptive system and the role of putative olfactory proteins in C. restitura. A total of 165 transcripts were identified, including 43 transcripts encoding putative odorant-binding proteins (OBPs), 13 chemosensory proteins (CSPs), 78 odorant receptors (ORs), 15 ionotropic receptors (IRs), 13 gustatory receptors (GRs), and 3 sensory neuron membrane proteins (SNMPs). Furthermore, we systematically analyzed expression patterns of eight OBPs from different tissues of both C. restitura sexes by using reverse transcription PCR and quantitative real time PCR (RT-qPCR). The expression level of CresGOBP2 in female antennae was approximately two times higher than in males, and two pheromone binding proteins PBPs (CresPBP1 and -PBP3) and three OBPs (CresOBP9, −10, and −16) were more highly enriched in male antennae than in female antennae. CresOBP10 showed a remarkably high expression in legs compared to other studied insects. Our results suggested that these proteins might play a key role in foraging, seeking mates, and host recognition in C. restitura. Our findings provided a foundation for future studies on the molecular mechanisms controlling the olfactory system in C. restitura and potential novel targets for pest control strategies. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract Galeruca daurica is a new pest causing great losses in the Inner Mongolian grasslands of China. The adults enter obligatory diapause during summer. However, the molecular mechanism of summer diapause remains unknown. We used iTRAQ to conduct proteomic analysis of adult G. daurica at the pre-diapause (PD), diapause (D) and post-diapause (TD) stages during summer diapause. A total of 139 and 118 differentially expressed proteins (DEPs) were detected in D/PD and TD/D comparisons, respectively. Besides a large number of DEPs involved in metabolic process, stress response, cytoskeletal reorganization, and phagosome pathway, many new proteins related to diapause were found in this study, such as encapsulation-relating proteins, odorant binding proteins, chemosensory proteins and ribosomal proteins. KEGG analysis revealed that the phagosome pathway was the only common significantly enriched pathway in both D/PD and TD/D. In addition, juvenile hormone regulation and Ca2+ signaling may play an important role in the regulation of summer diapause in G. daurica. Our proteomic analysis provides a new insight into the mechanism of obligatory summer diapause, and lays a foundation for future molecular level studies. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Anomala corpulenta is an insect pest that is widely distributed in China, and it can cause large economic losses in agriculture, horticulture, and forestry. It is difficult to control because most of the lifecycle is underground. Trapping adults would be an environmentally sustainable way to reduce damage caused by this insect. Odorant-binding proteins (OBPs) and chemosensory proteins (CSPs) are considered to be important chemodetection proteins. In this study, we investigate the expression of odorant-binding protein genes and chemosensory protein genes in different tissues of the adult and other developmental stages. The antenna had the highest expression levels for OBPs and CSPs of all tissues, except for OBP7 which was most highly expressed in the head without antenna. Besides the antenna, the head without antenna had the next highest expression levels for all OBP and CSP genes. The expression of OBP2, OBP3, OBP14, and CSP in the adult was higher than in other stages, while, OBP7 was lower than in other stages. Before estimating the expression of OBPs and CSPs, seven candidate reference genes were tested for stability among the tissues of adult and other development stages. GAPDH was the best reference gene in different tissues of the adult, and RPL13a was the best reference gene in different development stages. Our results provide a foundation for further research on the molecular aspects of chemical communication of this insect. [ABSTRACT FROM AUTHOR]

Samples were collected from six different organized industrial odor sources in Tianjin Binhai New Area, including pharmacy, paint spraying, oil refinery, petrochemical, resin synthesis, and rubber manufacturing. Chemical analysis was conducted to identify and quantify major odorous volatile organic compounds (VOCs) and subsequently, establish source profiles. Olfactory measurement was used to characterize the sensory stimulating intensity of odorous VOCs and express them as odor concentration. The TVOC mass concentrations of these six sources were between 10.9 and 225.3 mg/m3. Toluene was the most abundant component in profiles of both pharmacy and spraying sources with abundances of 79.1 and 94%, respectively. The petrochemical source was characterized by high levels of o,m,p-xylene (more than 60%). Sulfides were identified almost solely in the rubber manufacturing source. High levels of styrene were found in the resin synthesis source, whereas the oil refinery source was dominated by halocarbons. The odor concentration of oil refinery, spraying, rubber manufacturing, and resin synthesis all exceeded the Chinese emission standards for odor pollutants (GB14554-93) during the study period. Based on industrial processing analysis and factor analysis, toluene, m,p-xylene, carbon disulfide, toluene, three types of halogenated hydrocarbons, and styrene were the markers of pharmacy, petrochemical, rubber manufacturing, spraying, oil refinery, and resin synthesis sources, respectively. Production process and factor analysis methods were used to identify the markers of each odor source, which were based on instrument analysis and olfactory measurement. [ABSTRACT FROM AUTHOR]

A precise chemosensory system can help insects complete various important behavioral responses by accurately identifying different external odorants. Therefore, deeply understanding the mechanism of insect recognition of important odorants will help us develop efficient and environmentally-friendly behavioral inhibitors. Spodoptera frugiperda is a polyphagous pest that feeds on >350 different host plants worldwide and also harms maize production in China. However, the molecular mechanism of the first step for males to use odorant-binding proteins (OBPs) to recognize sex pheromones remains unclear. Here, we obtained 50 OBPs from the S. frugiperda genome, and the expression level of SfruGOBP1 in females was significantly higher than that in males, whereas SfruGOBP2 displayed male-biased expression. Fluorescence competitive binding assays showed that only SfruGOBP2 showed binding affinities for the four sex pheromones of female S. frugiperda. Subsequently, we identified some key amino acid residues that can participate in the interaction between SfruGOBP2 and sex pheromones using molecular docking and site-directed mutagenesis methods. These findings will help us explore the interaction mechanism between GOBPs and sex pheromones in moths, and provide important target genes for developing new mating inhibitors of S. frugiperda in the future. [Display omitted] • The expression level of SfruGOBP1 in females was significantly higher than that in males. • SfruGOBP2 displayed male-biased expression. • Only SfruGOBP2 showed binding affinities for the four sex pheromones of female S. frugiperda. • Some key amino acid residues that can participate in the interaction between SfruGOBP2 and sex pheromones. [ABSTRACT FROM AUTHOR]

[Display omitted] • Strip green tea (SGT) volatile metabolite variations during process were clarified. • Fixation and rubbing were the key processes responsible for SGT aroma formation. • Lipid and glycoside derivatization were crucial in the volatile conversion of SGT. • Thirty-four differential volatiles were identified at different rubbing degrees. • Moderate rubbing was beneficial to the shape and aroma formation of SGT. Strip green tea (SGT) is widely distributed in China owing to its unique appearance and aroma but the evolution and formation mechanisms of volatile metabolites (VMs) during SGT processing, and especially in the unique process of rubbing, remain unclear. In this study, based on untargeted metabolomics, 217 VMs (8 categories) were identified, and fixation and rubbing processes were found to be key for SGT aroma formation. Moreover, targeted metabolomics was applied to obtain 38 differential VMs and their related substances, of which fatty acid-derived volatiles (14 VMs) and glycoside-derived volatiles (8 VMs) showed significant contributions to SGT aroma, and their derivation laws during SGT manufacturing were clarified. Furthermore, the effect of rubbing degree on volatile metabolite formation was explored, and 11 key differential VMs were screened by variable importance in projection, and odor activity value analyses. Appropriate rubbing promoted the loss of grassy VMs (such as 1-octanol and 2-pentyl-furan) and enrichment of floral/fruity VMs (such as trans -β-ionone, nonanal, geraniol, citral, (Z)-3,7-dimethyl-2,6-octadien-1-ol, and (Z)-hexanoic acid, 3-hexenyl ester). Our study not only enriches the chemical theory of green tea processing but also provides technical support for the precision directional processing of high-quality SGT. [ABSTRACT FROM AUTHOR]

• We reported for the first time the identification of OR genes in the gastropod R. venosa. • Significant changes in OR genes expression in larvae from G3 stage to J4 stage indicate changes in larval olfactory function. • Larvae of R. venosa at the J4 stage (competent larva, 1000–1500 μm shell length) possess the ability to sense shellfish odor during settlement and metamorphosis. • The olfactory perception of R. venosa larvae is of great significance to settlement and metamorphosis behavior. The rapa whelk Rapana venosa , an economically important marine fishery resource in China but a major invader all over the world, changes from a phytophagous to a carnivorous form following settlement and metamorphosis. However, the low settlement and metamorphosis rates (<1%) of larvae limit the abundance of R. venosa. This critical step (settlement and metamorphosis) remains poorly characterized but may be related to how larvae perceive the presence of shellfish, their new source of food. Here, we report that larvae may use olfactory perception to sense shellfish. Olfactory receptor (OR) genes are involved in odor sensing in animals. We identified a total of 463 OR genes, which could be grouped into nine clades based on phylogenetic analysis. When assessing the attraction of larvae at different developmental stages to oyster odor , R. venosa showed active settlement and metamorphosis behavior only at the J4 stage (competent larva, 1000–1500 μm shell length) and in the presence of shellfish odor at the same time. Expression of OR gene family members differed between stage 2 (four-spiral whorl stage) and stage 1 (single- to three-spiral whorl stage), indicating significant changes in the olfactory system during larval development. These findings broaden our understanding of olfactory perception, settlement, and metamorphosis in gastropods and can be used to improve R. venosa harvesting, as well as the sustainable development and utilization of this resource. [ABSTRACT FROM AUTHOR]

BACKGROUND: Monitoring traps and control methods are needed for the long-legged chafer, Hoplia spectabilis Medvedev, which has recently reached outbreak numbers in pastureland of Qinghai Province, China. RESULTS: Field trapping experiments, using cross-pane funnel (barrier) traps, showed that H. spectabilis adults were not significantly attracted to branches of the host plant Dasiphora fructicosa (L.) Rydb. However, beetles were slightly attracted to similar host plant branches infested by conspecific beetles, possibly owing to weakly attractive volatiles, primarily ( Z)-3-hexenyl acetate, released from beetle-damaged host leaves. This compound was weakly attractive when released from traps. However, H. spectabilis beetles showed strong visual responses to yellow- or white-painted trap panes, with weaker responses to blue, red or green panes, and least response to black panes. Black traps at 0.2-1.5 m above ground intercepted significantly more beetles than traps at 2.5 m. The mean flight height based on trap catches was 0.88 m (SD = 0.76), yielding an effective flight layer of 1.9 m. Flight response of beetles to colored barrier traps occurred between 10:00 and 18:00, and peaked between 12:00-14:00, when daily temperatures reached their maximum. CONCLUSION: Unbaited yellow or white cross-pane funnel traps are recommended for both monitoring and mass-trapping programs against this economically and ecologically important scarab beetle. Copyright © 2010 Society of Chemical Industry [ABSTRACT FROM AUTHOR]