Figure - available from: Communications Biology
This content is subject to copyright. Terms and conditions apply.
Electrophysiological responses of s6 sensillum in control and mutant flies. a Schematic representation of the tip-recording method used to record the electrophysiological activity of a single sensillum on the Drosophila proboscis. The stimulus was contained in a glass microelectrode that capped the tip of the sensillum. Amino acids were dissolved in 1 mM KCl solution. Recordings were obtained from s6 sensilla in control CS and OBP19b-Gal4 mutant female flies. b Representative traces of tip-recording data obtained from control and OBP19b-Gal4 mutant flies after stimulation by 10 mM l-phenylalanine (l-Phe) and by 1 mM KCl. c Histograms representing the mean ± SEM for the number of spikes/s obtained in control and mutant flies in response to stimulation by 3 mM and 10 mM l-Phe, 10 mM d-phenylalanine (d-Phe) and by 1 mM KCl. l-Phe spikes might mask or interfere water response. Thus, the total number of spikes shown here is not a simple summation of spikes elicited by water and l-Phe. Letters indicate significant differences determined with ANOVA and Tukey’s post hoc test (a/b or b/c: p < 0.01; a/c: p < 0.001); N = 8–12.
Source publication
Animals need to detect in the food essential amino acids that they cannot synthesize. We found that the odorant binding protein OBP19b, which is highly expressed in Drosophila melanogaster taste sensilla, is necessary for the detection of several amino acids including the essential l-phenylalanine. The recombinant OBP19b protein was produced and ch...
Similar publications
When flies explore their environment, they encounter odors in complex, highly intermittent plumes. To navigate a plume and, for example, find food, they must solve several challenges, including reliably identifying mixtures of odorants and their intensities, and discriminating odorant mixtures emanating from a single source from odorants emitted fr...
Citations
... OBP49a, which is expressed in the thecogen cells, accessory cells of the sensory neurons in the sensillum, acts in the inhibition of sweet sensing neurons by bitter chemicals [20]. OBP19b has been implicated in amino acid sensation [21]. Furthermore, RNAi-induced decrease of the expression of individual Obp genes led to either increased or decreased consumption of sucrose in the presence of bitter compounds [22]. ...
... Drosophilaodorant binding proteins (OBPs) were initially described in olfactory sensilla [25], and initial studies on the OBPs mainly focused on the olfactory system among the chemosensory systems. A subset of Drosophila OBPs were previously reported to be expressed in taste appendages [5,7,20,21,26], and these proteins were recently discovered to express in other chemosensory and non-chemosensory organs [8]. However, a systematic characterization of the expression of all members of the Obp gene family has not yet been attempted. ...
... The Drosophila labellum has sensilla which are composed of sensory neurons, supporting cells, and glial cells wrapping the sensory neurons' axons ( Fig. 4A). We observed that 17 Obp-GAL4 drivers expressed in the labellum (Figs. 1 and 3), including the previously reported Obp19b [21], with expression in diverse cell types such as the sensory neurons, glia, gland, supporting cells, and some cells that were difficult to identify by gross anatomy (Fig. 3). To identify the positions and types of the cells where each Obp-GAL4 transgene was expressed, we used the UAS-RedStinger/UASmyr.GFP reporter, which marks the nucleus with RFP and intracellular membrane weakly with GFP (Fig. S2). ...
Chemosensation is important for the survival and reproduction of animals. The odorant binding proteins (OBPs) are thought to be involved in chemosensation together with chemosensory receptors. While OBPs were initially considered to deliver hydrophobic odorants to olfactory receptors in the aqueous lymph solution, recent studies suggest more complex roles in various organs. Here, we use GAL4 transgenes to systematically analyze the expression patterns of all 52 members of the Obp gene family and 3 related chemosensory protein genes in adult Drosophila, focusing on chemosensory organs such as the antenna, maxillary palp, pharynx, and labellum, and other organs such as the brain, ventral nerve cord, leg, wing, and intestine. The OBPs were observed to express in diverse organs and in multiple cell types, suggesting that these proteins can indeed carry out diverse functional roles. Also, we constructed 10 labellar-expressing Obp mutants, and obtained behavioral evidence that these OBPs may be involved in bitter sensing. The resources we constructed should be useful for future Drosophila OBP gene family research.
... Frontiers in Nutrition 05 frontiersin.org secreted from nearby cells can bind certain amino acids to impact their detection by taste cells (121), but it is unclear how conserved this mechanism may be. Despite some differences from the mammalian system, the Drosophila model offers a way to study dose-dependent encoding of individual or groups of amino acids to better understand this canonical yet complex taste modality. ...
Across species, taste provides important chemical information about potential food sources and the surrounding environment. As details about the chemicals and receptors responsible for gustation are discovered, a complex view of the taste system is emerging with significant contributions from research using the fruit fly, Drosophila melanogaster, as a model organism. In this brief review, we summarize recent advances in Drosophila gustation and their relevance to taste research more broadly. Our goal is to highlight the molecular mechanisms underlying the first step of gustatory circuits: ligand-receptor interactions in primary taste cells. After an introduction to the Drosophila taste system and how it encodes the canonical taste modalities sweet, bitter, and salty, we describe recent insights into the complex nature of carboxylic acid and amino acid detection in the context of sour and umami taste, respectively. Our analysis extends to non-canonical taste modalities including metals, fatty acids, and bacterial components, and highlights unexpected receptors and signaling pathways that have recently been identified in Drosophila taste cells. Comparing the intricate molecular and cellular underpinnings of how ligands are detected in vivo in fruit flies reveals both specific and promiscuous receptor selectivity for taste encoding. Throughout this review, we compare and contextualize these Drosophila findings with mammalian research to not only emphasize the conservation of these chemosensory systems, but to demonstrate the power of this model organism in elucidating the neurobiology of taste and feeding.
... OBP sequence of flies has a substantial amount of histidine in Nterminal-extension whereas ants, beetles, and wasps represent the same in C-terminal extension having great binding affinity with metals like zinc, nickel and copper suggesting the essential role of histidine and acidic amino acids in metal binding (Shah et al., 2022). Similarly, OBP19b of Drosophila exhibited great binding affinity with L-glutamine and L-phenylalanine, emphasising its vital role in the detection of essential amino acids (Rihani et al., 2019). Conformational changes in N and C terminal leads to binding of OBP with different compounds. ...
... Some OBPs may be associated with insect taste perception, mating behavior, nymph survival or insecticide resistance. [19][20][21][22] The red palm weevil (RPW), Rhynchophorus ferrugineus Olivier, is a devastating transboundary pest for palm plants, causing significant economic damage globally. 23 RPW feeds not only on important economic plants such as date palm (Phoenix dactylifera), coconut (Cocos nucifera), oil palm (Elaeis guineensis), sago palm (Metroxylon sagu) and sugar palm (Arenga pinnata) but also on ornamental plants such as Canary Island date palm (Phoenix canariensis), ribbon palm (Livistona decora) and Chinese fan palm (Livistona chinensis). ...
BACKGROUND
Rhynchophorus ferrugineus, the red palm weevil (RPW), is a key pest that attacks many economically important palm species and that has evolved a sensitive and specific olfactory system to seek palm hosts. Odorant‐binding proteins (OBPs) not only play crucial roles in its olfactory perception process but are also important molecular targets for the development of new approaches for pest management.
RESULTS
Analysis of the tissue expression profiles of RferOBP8 and RferOBP11 revealed that these two Rhynchophorus ferrugineus odorant binding proteins (RferOBPs) exhibited high expression in the antennae and showed sexual dimorphism. We analyzed the volatiles of seven host plants by gas chromatography–mass spectrometry and screened 13 potential ligands by molecular docking. The binding affinity of two recombinant OBPs to aggregation pheromones and 13 palm odorants was tested by fluorescence competitive binding assays. The results revealed that eight tested palm volatiles and ferrugineol have high binding affinities with RferOBP8 or RferOBP11. Behavioral trials showed that these eight odor compounds could elicit an attraction response in adult RPW. RNA interference analysis indicated that the reduction in the expression levels of the two RferOBPs led to a decrease in behavioral responses to these volatiles.
CONCLUSION
These results suggest that RferOBP8 and RferOBP11 are involved in mediating the responses of RPW to palm volatiles and to aggregation pheromones and may play important roles in RPW host‐seeking. This study also provides a theoretical foundation for the promising application of novel molecular targets in the development of new behavioral interference strategies for RPW management in the future. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
... Chemosensory pathways in D. v. virgifera are involved in perception of plant volatiles attracting larvae to roots [88,89], adults to oviposition [90] and feeding sites [91], and sexual communication [92,93]. OBPs are soluble proteins present in the sensillar lymph that were initially believed to transport odorants to the chemoreceptors, but now are recognized as playing diverse olfactory and non-olfactory roles [94][95][96][97][98][99]. ORs of beetles comprise exceptionally large radiations of chemoreceptors and are the primary means by which volatile compounds are recognized by the olfactory system [73]. ...
Background
Adaptations by arthropod pests to host plant defenses of crops determine their impacts on agricultural production. The larval host range of western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae), is restricted to maize and a few grasses. Resistance of D. v. virgifera to crop rotation practices and multiple insecticides contributes to its status as the most damaging pest of cultivated maize in North America and Europe. The extent to which adaptations by this pest contributes to host plant specialization remains unknown.
Results
A 2.42 Gb draft D. v. virgifera genome, Dvir_v2.0, was assembled from short shotgun reads and scaffolded using long-insert mate-pair, transcriptome and linked read data. K-mer analysis predicted a repeat content of ≥ 61.5%. Ortholog assignments for Dvir_2.0 RefSeq models predict a greater number of species-specific gene duplications, including expansions in ATP binding cassette transporter and chemosensory gene families, than in other Coleoptera. A majority of annotated D. v. virgifera cytochrome P450s belong to CYP4, 6, and 9 clades. A total of 5,404 transcripts were differentially-expressed between D. v. virgifera larvae fed maize roots compared to alternative host (Miscanthus), a marginal host (Panicum virgatum), a poor host (Sorghum bicolor) and starvation treatments; Among differentially-expressed transcripts, 1,908 were shared across treatments and the least number were between Miscanthus compared to maize. Differentially-expressed transcripts were enriched for putative spliceosome, proteosome, and intracellular transport functions. General stress pathway functions were unique and enriched among up-regulated transcripts in marginal host, poor host, and starvation responses compared to responses on primary (maize) and alternate hosts.
Conclusions
Manual annotation of D. v. virgifera Dvir_2.0 RefSeq models predicted expansion of paralogs with gene families putatively involved in insecticide resistance and chemosensory perception. Our study also suggests that adaptations of D. v. virgifera larvae to feeding on an alternate host plant invoke fewer transcriptional changes compared to marginal or poor hosts. The shared up-regulation of stress response pathways between marginal host and poor host, and starvation treatments may reflect nutrient deprivation. This study provides insight into transcriptomic responses of larval feeding on different host plants and resources for genomic research on this economically significant pest of maize.
... Both leg-expressed OBP57d and OBP57e respond in a speciesspecific manner to C6-C9 fatty acids and elicit egg-laying behavior [29]. Additionally, the proboscis-expressed OBP19b is necessary to transport essential amino acids [30]. OBP59a, which is expressed in the second antennal segment, is implicated in hygrosensation [31,32]. ...
... We believe that our proteomic analysis missed several proteins expressed at a minute level in the proboscis. For instance, despite the high number of dissected proboscis, we did not detect OBP19b, which is nevertheless present in this taste organ, given that it is involved in the detection of amino acids by the proboscis taste sensilla [30]. While the evaluation of the level of protein expression based on mRNA expression could be a useful approach in some cases, it remains difficult to carry out, given the possible posttranslational modifications and also for technical reasons due to the devices used to detect proteins or mRNA levels. ...
Drosophila melanogaster flies use their proboscis to taste and distinguish edible compounds from toxic compounds. With their proboscis, flies can detect sex pheromones at a close distance or by contact. Most of the known proteins associated with probosci’s detection belong to gustatory receptor families. To extend our knowledge of the proboscis-taste proteins involved in chemo-detection, we used a proteomic approach to identify soluble proteins from Drosophila females and males. This investigation, performed with hundreds of dissected proboscises, was initiated by the chromatographic separation of tryptic peptides, followed by tandem mass spectrometry, allowing for femtomole detection sensitivity. We found 586 proteins, including enzymes, that are involved in intermediary metabolism and proteins dedicated to various functions, such as nucleic acid metabolism, ion transport, immunity, digestion, and organ development. Among 60 proteins potentially involved in chemosensory detection, we identified two odorant-binding proteins (OBPs), i.e., OBP56d (which showed much higher expression in females than in males) and OBP19d. Because OBP56d was also reported to be more highly expressed in the antennae of females, this protein can be involved in the detection of both volatile and contact male pheromone(s). Our proteomic study paves the way to better understand the complex role of Drosophila proboscis in the chemical detection of food and pheromonal compounds.
... For example, the NlugOBP3 is associated with the nymph survival of Nilaparvata lugens [18]. Some OBPs might be related to insect taste perception or involved in insecticide resistance [19][20][21][22][23][24]. CSPs are much smaller and more conserved than OBPs, which have the four typically conserved cysteine residues forming two disulphide bridges [6,25,26]. ...
... Thus, we speculate that the nine OBPs and three CSPs, which are highly expressed in N. cincticeps antennae, might be involved in the perception and discrimination of the two rice volatiles induced by RDV infection. In addition, two OBP (NcinOBP12, OBP14) and two CSP genes (NcinCSP1, CSP5, CSP7, CSP8) are markedly expressed in N. cincticeps head and leg compared with antennae respectively, which may play other functions, for instance, carriers of visual pigments, regeneration and development, anti-inflammatory action, nutrition or insecticide resistance [4,24,71]. The specific functions of these OBP and CSP genes will be studied in the next step. ...
The insect odorant binding proteins (OBPs) and chemosensory proteins (CSPs) are involved in the perception and discrimination of insects to host odor cues. Nephotettix cincticeps, one of the destructive pests of rice plants, not only directly damages hosts by sucking, but also indirectly transmits plant viruses in the field. Previous study found that two rice volatiles ((E)-β-caryophyllene and 2-heptanol) induced by rice dwarf virus (RDV) mediated the olfactory behavior of N. cincticeps, which may promote virus dispersal. However, the OBPs and CSPs in N. cincticeps are still unknown. In this study, to identify the OBP and CSP genes in N. cincticeps, transcriptomic analyses were performed. In total, 46,623 unigenes were obtained. Twenty putative OBP and 13 CSP genes were discovered and identified. Phylogenetic analyses revealed that five putative OBPs belonged to the plus-C OBP family, and the other classic OBPs and CSPs were distributed among other orthologous groups. A total of 12 OBP and 10 CSP genes were detected, and nine OBP and three CSP genes were highly expressed in N. cincticeps antennae compared with other tissues. This study, for the first time, provides a valuable resource to well understand the molecular mechanism of N. cincticeps in the perception and discrimination of the two volatiles induced by RDV infection.
... Together, these data are consistent with a combination of the carrier and presentation models for OBP function and implicate a direct interaction between the LUSH and Or67d-Orco pheromone receptors on the dendrites. Following these studies, many groups have demonstrated specific roles for OBP members in the detection of volatile ligands in many species [79][80][81][82][83][84][85][86][87][88], and even for tastants and humidity [89,90]. Finally, in Drosophila, an odorant-binding protein has been implicated in blocking sugar taste detection when sucrose is present with bitter compounds [91]. ...
Human and insect olfaction share many general features, but insects differ from mammalian systems in important ways. Mammalian olfactory neurons share the same overlying fluid layer in the nose, and neuronal tuning entirely depends upon receptor specificity. In insects, the olfactory neurons are anatomically segregated into sensilla, and small clusters of olfactory neurons dendrites share extracellular fluid that can be independently regulated in different sensilla. Small extracellular proteins called odorant-binding proteins are differentially secreted into this sensillum lymph fluid where they have been shown to confer sensitivity to specific odorants, and they can also affect the kinetics of the olfactory neuron responses. Insect olfactory receptors are not G-protein-coupled receptors, such as vertebrate olfactory receptors, but are ligand-gated ion channels opened by direct interactions with odorant molecules. Recently, several examples of insect olfactory neurons expressing multiple receptors have been identified, indicating that the mechanisms for neuronal tuning may be broader in insects than mammals. Finally, recent advances in genome editing are finding applications in many species, including agricultural pests and human disease vectors.
... In addition, the OBPs abundantly expressed in female and/or male reproductive tissues may be candidates for the development, as implied in Drosophila melanogaster. 45 In insects, some OBPs highly expressed in taste organs including the proboscis are involved in gustatory perception, such as DmelOBP19b and DmelOBP49a in D. melanogaster, 46,47 DsecOBP57d and DsecOBP57e in Drosophila sechellia, 48 as well as PregOBP56a in Phormia regina. 49 In P. xuthus, Ugajin and Ozaki reported the expression of 44 OBPs in the foreleg tarsus, a critical taste organ. ...
In this study, we annotated 49 odorant-binding proteins (OBPs) in Papilio xuthus, with four novel genes and seven improved sequences. Expression profiles identified numerous OBPs in antennae or reproductive tissues. Using two antenna-enriched general OBPs (PxutGOBP1 and PxutGOBP2) as targets, we screened three key compounds by a reverse chemical ecology strategy. Of these, an oviposition stimulant vicenin-2 could strongly interact with PxutGOBP1, representing a dissociation constant (Ki) value of 10.34 ± 0.07 μM. Molecular simulations and site-directed mutagenesis revealed the importance of His66, Thr73, and Phe118 between PxutGOBP1 and vicenin-2 interactions. Two other compounds, an ordinary floral scent β-ionone and a widely used insecticide chlorpyrifos, exhibited high affinities to PxutGOBPs (Ki < 13 μM). Furthermore, two mutations His66Ala and Thr73Ala of PxutGOBP1 significantly reduced the binding to chlorpyrifos. Our study provides insights into the putative roles of PxutGOBPs in odorant perception and identifies key binding sites of PxutGOBP1 to vicenin-2 and chlorpyrifos.
... Activation of the olfactory receptor DmelOR67d requires a complex comprised of LUSH (DmelOBP76a) and cis-vaccenyl acetate (cVA), the male-specific pheromone of Drosophila melanogaster, rather than cVA alone [12]. Involved in the uptake of nutrients, DmelOBP19b, highly expressed in D. melanogaster taste sensilla, is necessary for detection of L-phenylalanine and L-glutamine that it cannot synthesize [13]. The regulation of release of pheromones may be contributed by OBP10 in seminal fluid of Helicoverpa armigera and H. assulta [14]. ...
As a quarantine pest of conifer, Sirex noctilio has caused widespread harm around the world. It is expected that the molecular mechanism of protein–ligand binding can be elucidated to carry out the pest control. Through studies of SnocOBP12–ligand hydrophobic binding and dynamics and responsible amino acid residues identification, we got some promising results. SnocOBP12 had a general and excellent affinity for host plant volatiles, and may be a key protein for S. noctilio to find host plants. Among the many odor molecules that are bound to SnocOBP12, (−)-α-cedrene and (E)-β-farnesene from host plants and (−)-globuol from the symbiotic fungi of Sirex noctilio stood out and formed highly stable complexes with SnocOBP12. By the molecular mechanics Poisson–Boltzmann surface area (MM-PBSA) method, the calculated free binding energy of the three complexes was −30.572 ± 0.101 kcal/mol, −28.349 ± 0.119 kcal/mol and −25.244 ± 0.152 kcal/mol, respectively. It was found that the van der Waals energy contributed to the stability of the complexes. Some key amino acid residues were also found: LEU74 and TYR109 were very important for SnocOBP12 to stably bind (−)-α-cedrene, while for (E)-β-farnesene, ILE6, MET10, and LEU74 were very important for the stable binding system. We discovered three potential ligands and analyzed the interaction pattern of the protein with them, this paper provides a favorable molecular basis for optimizing the attractant formulation. Investigation of the binding characteristics in the olfactory system at the molecular level is helpful to understand the behavior of S. noctilio and develop new methods for more effective and environmentally friendly pest control.
