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Li R, Song X, Shan S, Hussain Dhiloo K, Wang S, Yin Z, Lu Z, Khashaveh A, Zhang Y. Female-Biased Odorant Receptor MmedOR48 in the Parasitoid Microplitis mediator Broadly Tunes to Plant Volatiles. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024. [PMID: 39052973 DOI: 10.1021/acs.jafc.4c02737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
Odorant receptors (ORs) play a crucial role in insect chemoreception. Here, a female-biased odorant receptor MmedOR48 in parasitoid Microplitis mediator was fully functionally characterized. The qPCR analysis suggested that the expression level of MmedOR48 increased significantly after adult emergence and was expressed much more in the antennae. Moreover, an in situ hybridization assay showed MmedOR48 was extensively located in the olfactory sensory neurons. In two-electrode voltage clamp recordings, recombinant MmedOR48 was broadly tuned to 23 kinds of volatiles, among which five plant aldehyde volatiles excited the strongest current recording values. Subsequent molecular docking analysis coupled with site-directed mutagenesis demonstrated that key amino acid residues Thr142, Gln80, Gln282, and Thr312 together formed the binding site in the active pocket for the typical aldehyde ligands. Furthermore, ligands of MmedOR48 could stimulate electrophysiological activities in female adults of the M. mediator. The main aldehyde ligand, nonanal, aroused significant behavioral preference of M. mediator in females than in males. These findings suggest that MmedOR48 may be involved in the recognition of plant volatiles in M. mediator, which provides valuable insight into understanding the olfactory mechanisms of parasitoids.
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Affiliation(s)
- Ruijun Li
- College of Plant Protection, Hebei Agricultural University, Baoding 071000, China
| | - Xuan Song
- College of Plant Protection, Hebei Agricultural University, Baoding 071000, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Shuang Shan
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- State Key Laboratory of Resource Insects, Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Khalid Hussain Dhiloo
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Department of Entomology, Faculty of Crop Protection, Sindh Agriculture University, Tandojam 70060, Pakistan
| | - Shanning Wang
- Beijing Key Laboratory of Environment Friendly Management on Fruit Diseases and Pests in North China, Institute of Plant Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China
| | - Zixuan Yin
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Ziyun Lu
- IPM Center of Hebei Province, Key Laboratory of Integrated Pest Management on Crops in Northern Region of North China, Ministry of Agriculture and Rural Affairs, Hebei Academy of Agricultural and Forestry Sciences, Baoding, Hebei 071000, China
| | - Adel Khashaveh
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yongjun Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
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Yan R, Chen P, Xu Z, Qian J, Zhu G, Jin Y, Chen B, Chen M. A potential link between aromatics-induced oviposition repellency behaviors and specific odorant receptor of Aedes albopictus. PEST MANAGEMENT SCIENCE 2024; 80:3603-3611. [PMID: 38458148 DOI: 10.1002/ps.8064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Revised: 02/21/2024] [Accepted: 03/07/2024] [Indexed: 03/10/2024]
Abstract
BACKGROUND The Asian tiger mosquito, Aedes albopictus, is a competent vector for the spread of several viral arboviruses including dengue, chikungunya, and Zika. Several vital mosquito behaviors linked to survival and reproduction are primarily dependent on a sophisticated olfactory system for semiochemical perception. However, a limited number of studies has hampered our understanding of the relationship between the A. albopictus acute olfactory system and the complex chemical world. RESULTS Here, we performed a qRT-PCR assay on antennae from A. albopictus of differing sex, age and physiological states, and found that AalbOr10 was enriched in blood-fed female mosquitoes. We then undertook single sensillum recording to de-orphan AalbOr10 using a panel of physiologically and behaviorally relevant odorants in a Drosophila 'empty neuron' system. The results indicated that AalbOr10 was activated by seven aromatic compounds, all of which hampered egg-laying in blood-fed mosquitoes. Furthermore, using a post-RNA interference oviposition assay, we found that reducing the transcript level of AalbOr10 affected repellent activity mediated by 2-ethylphenol at low concentrations (10-4 vol/vol). Computational modeling and molecular docking studies suggested that hydrogen bonds to Y68 and Y150 mediated the interaction of 2-ethylphenol with AalbOr10. CONCLUSION We reveal a potential link between aromatics-induced oviposition repellency behaviors and a specific odorant receptor in A. albopictus. Our findings provide a foundation for identifying active semiochemicals for the monitoring or controlling of mosquito populations. © 2024 Society of Chemical Industry.
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Affiliation(s)
- Ru Yan
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Peitong Chen
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, China
| | - Zhanyi Xu
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, China
| | - Jiali Qian
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, China
| | - Guonian Zhu
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, China
| | - Yongfeng Jin
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Bosheng Chen
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou, China
| | - Mengli Chen
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou, China
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Halty-deLeon L, Pal Mahadevan V, Wiesel E, Hansson BS, Wicher D. Response Plasticity of Drosophila Olfactory Sensory Neurons. Int J Mol Sci 2024; 25:7125. [PMID: 39000230 PMCID: PMC11241008 DOI: 10.3390/ijms25137125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 06/10/2024] [Accepted: 06/23/2024] [Indexed: 07/16/2024] Open
Abstract
In insect olfaction, sensitization refers to the amplification of a weak olfactory signal when the stimulus is repeated within a specific time window. In the vinegar fly, Drosophila melanogaster, this occurs already at the periphery, at the level of olfactory sensory neurons (OSNs) located in the antenna. In our study, we investigate whether sensitization is a widespread property in a set of seven types of OSNs, as well as the mechanisms involved. First, we characterize and compare the differences in spontaneous activity, response velocity and response dynamics, among the selected OSN types. These express different receptors with distinct tuning properties and behavioral relevance. Second, we show that sensitization is not a general property. Among our selected OSN types, it occurs in those responding to more general food odors, while OSNs involved in very specific detection of highly specific ecological cues like pheromones and warning signals show no sensitization. Moreover, we show that mitochondria play an active role in sensitization by contributing to the increase in intracellular Ca2+ upon weak receptor activation. Thus, by using a combination of single sensillum recordings (SSRs), calcium imaging and pharmacology, we widen the understanding of how the olfactory signal is processed at the periphery.
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Affiliation(s)
| | | | - Eric Wiesel
- Max Planck Institute for Chemical Ecology, 07745 Jena, Germany
| | - Bill S Hansson
- Max Planck Institute for Chemical Ecology, 07745 Jena, Germany
| | - Dieter Wicher
- Max Planck Institute for Chemical Ecology, 07745 Jena, Germany
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Liu L, Yang L, Yuan J, Zhang J, Liu C, Zhou H, Liu W, Wang G. D-Limonene Is the Active Olfactory Attractant in Orange Juice for Bactrocera dorsalis (Insecta: Diptera: Tephritidae). Life (Basel) 2024; 14:713. [PMID: 38929696 PMCID: PMC11205096 DOI: 10.3390/life14060713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Revised: 05/22/2024] [Accepted: 05/24/2024] [Indexed: 06/28/2024] Open
Abstract
The oriental fruit fly, Bactrocera dorsalis (Hendel), poses a significant threat to the global fruit industry, causing damage to diverse fruits like citrus, mango, and guava. Chemical pesticides have limited effectiveness, and pesticide residues and pesticide resistance are pressing issues. Therefore, it is essential to develop environmentally friendly pest control methods to address this problem. Behavior-modifying chemicals, including male attractants and intersex protein baits, play a critical role in the control of B. dorsalis. The mature host fruit serves as both an oviposition site and food source under natural conditions, making it a potential attraction source for oriental fruit flies. Orange, Citrus sinensis, is a main host of B. dorsalis, and commercial orange juice is a common attractant for the egg laying of B. dorsalis. Although it can both attract and elicit oviposition behaviors in B. dorsalis adults, its active components are still unclear. This study utilized analytical chemistry, behavioral tests, and electrophysiology to identify the active components of commercial orange juice that attract B. dorsalis, with the aim of providing a reference for the development of behavior-modifying chemical-based techniques to control B. dorsalis. Five compounds with a high abundance were identified via a GC-MS, including D-Limonene, butanoic acid ethyl ester, β-myrcene, linalool, and α-terpineol. Behavioral and electrophysiological experiments uncovered that D-Limonene was the active substance that was the main attractant in the mixture of these five substances, evoking a strong electrophysiological response in adult B. dorsalis. D-Limonene strongly attracts adult B. dorsalis only when they are sexually mature, and the attraction is not rhythmic. Olfaction plays a leading role in the attraction of D-Limonene to adult B. dorsalis, and Orco-/- mediates the perception of D-Limonene by B. dorsalis. Overall, D-Limonene is one of the key attractant compounds for B. dorsalis in the volatile compounds of commercial orange juice, offering possible support for the development of behavior-modifying chemical-based technology to control B. dorsalis in the future.
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Affiliation(s)
- Leyuan Liu
- College of Plant Health & Medicine, Qingdao Agricultural University, Qingdao 266071, China; (L.L.); (H.Z.)
| | - Lang Yang
- Guangxi Key Laboratory of Biology for Crop Diseases and Insect Pests/Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture and Rural Affairs/Plant Protection Research Institution, Guangxi Academy of Agricultural Sciences, Nanning 530007, China;
| | - Jinxi Yuan
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China;
| | - Jie Zhang
- Key Laboratory of Sustainable Management of Forest Ecosystem, Ministry of Education, Northeast Forestry University, Harbin 150040, China; (J.Z.); (C.L.)
| | - Chenhao Liu
- Key Laboratory of Sustainable Management of Forest Ecosystem, Ministry of Education, Northeast Forestry University, Harbin 150040, China; (J.Z.); (C.L.)
| | - Hongxu Zhou
- College of Plant Health & Medicine, Qingdao Agricultural University, Qingdao 266071, China; (L.L.); (H.Z.)
| | - Wei Liu
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China;
| | - Guirong Wang
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China;
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Luo Z, Zhang Y, Zhang P, Liu L, Yuan J, Yan S, Liu W, Wang G. Benzaldehyde acts as a behaviorally active component in brewer's yeast protein powder which attracts B. dorsalis through olfaction. J Chem Ecol 2024:10.1007/s10886-024-01500-2. [PMID: 38740727 DOI: 10.1007/s10886-024-01500-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 04/07/2024] [Accepted: 04/25/2024] [Indexed: 05/16/2024]
Abstract
The Oriental fruit fly, Bactrocera dorsalis, is a significant pest that damages a variety of fruit crops. The effectiveness of chemical pesticides against such pests is limited, raising concerns about pesticide residues and resistance. Proteins naturally attract B. dorsalis and have led to the development of a management strategy known as protein bait attractant technology (BAT). Although the attraction of protein sources to B. dorsalis is well-documented, the biologically active components within these sources are not fully understood. This study employed analytical chemistry, behavioral tests, and electrophysiological techniques to investigate the behaviorally active components of beer yeast protein powder (BYPD), aiming to provide a basis for improving and developing protein baits. An olfactory trap assay confirmed the attractiveness of BYPD, and five components with high abundance were identified from its headspace volatiles using GC-MS. These components included ethanol, isoamyl alcohol, ethyl decanoate, benzaldehyde, and phenylethyl alcohol. Mixtures of these five components demonstrated significant attraction to B. dorsalis adults, with benzaldehyde identified as a potential key component. The attractiveness of benzaldehyde required a relatively large dose, and it was most attractive to adults that had been starved from dusk until the following morning. Attraction of adult flies to benzaldehyde appeared mainly mediated by inputs from olfactory receptors. While EAG data supports that ionotropic receptors could influence the detection of benzaldehyde in female adults, they did not affect female behavior towards benzaldehyde. These findings indicate that benzaldehyde is an important behaviorally active component in BYPD and offer insights for developing novel protein lures to control B. dorsalis in an environmentally friendly manner.
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Affiliation(s)
- Zhicai Luo
- Key Laboratory of Sustainable Management of Forest Ecosystem, Northeast Forestry University, Ministry of Education, Harbin, 150040, China
| | - Yan Zhang
- Key Laboratory of Sustainable Management of Forest Ecosystem, Northeast Forestry University, Ministry of Education, Harbin, 150040, China
| | - Panpan Zhang
- Key Laboratory of Sustainable Management of Forest Ecosystem, Northeast Forestry University, Ministry of Education, Harbin, 150040, China
| | - Leyuan Liu
- College of Plant Health & Medicine, Qingdao Agricultural University, Qingdao, 266071, China
| | - Jinxi Yuan
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
| | - Shanchun Yan
- Key Laboratory of Sustainable Management of Forest Ecosystem, Northeast Forestry University, Ministry of Education, Harbin, 150040, China.
| | - Wei Liu
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China.
| | - Guirong Wang
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
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Castellan I, Duménil C, Rehermann G, Eisenstecken D, Bianchi F, Robatscher P, Spitaler U, Favaro R, Schmidt S, Becher PG, Angeli S. Chemical and Electrophysiological Characterisation of Headspace Volatiles from Yeasts Attractive to Drosophila suzukii. J Chem Ecol 2024:10.1007/s10886-024-01494-x. [PMID: 38691267 DOI: 10.1007/s10886-024-01494-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 04/01/2024] [Accepted: 04/05/2024] [Indexed: 05/03/2024]
Abstract
Chemical control of Drosophila suzukii (Diptera: Drosophilidae) based on the use of insecticides is particularly challenging as the insect attacks ripening fruits shortly before harvest. An alternative strategy may rely on the use of yeasts as phagostimulants and baits, applied on canopy as attract-and-kill formulations. The aim of this research was to identify the most attractive among six yeast species for D. suzukii: Saccharomyces cerevisiae, Hanseniaspora uvarum, Clavispora santaluciae, Saccharomycopsis vini, Issatchenkia terricola, and Metschnikowia pulcherrima. The volatile profile of C. santaluciae was described for the first time. Behavioural experiments identified H. uvarum and S. vini as the most attractive yeasts. The characterization of yeast headspace volatiles using direct headspace (DHS) and solid-phase microextraction (SPME) revealed several strain-specific compounds. With DHS injection, 19 volatiles were characterised, while SPME revealed 71 compounds constituting the yeast headspace. Both analyses revealed terpenoids including β-ocimene, citronellol, (Z)-geraniol (nerol), and geranial as distinct constituents of S. vini. H. uvarum and S. vini were further investigated using closed-loop stripping analysis (CSLA) and electroantennography. Out of 14 compounds quantified by CSLA, ethyl acetate, isoamyl acetate, β-myrcene, benzaldehyde and linalool were detected by D. suzukii antennae and might generate the strong attractiveness of S. vini and H. uvarum. Our results highlight a strong attraction of D. suzukii to various yeasts associated with both the flies and their habitat and demonstrate how different sampling methods can impact the results of volatile compound characterization. It remains to be demonstrated whether the distinct attraction is based on special adaptations to certain yeasts and to what extent the metabolites causing attraction are interchangeable.
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Affiliation(s)
- Irene Castellan
- Faculty of Agricultural, Environmental and Food Sciences, Free University of Bozen-Bolzano, Bolzano, Italy
| | - Claire Duménil
- Faculty of Agricultural, Environmental and Food Sciences, Free University of Bozen-Bolzano, Bolzano, Italy
| | - Guillermo Rehermann
- Department of Plant Protection Biology, Chemical Ecology Horticulture Unit, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Daniela Eisenstecken
- Laboratory for Flavours and Metabolites, Institute for Agricultural Chemistry and Food Quality, Laimburg Research Centre, Auer-Ora, Italy
| | - Flavia Bianchi
- Laboratory for Flavours and Metabolites, Institute for Agricultural Chemistry and Food Quality, Laimburg Research Centre, Auer-Ora, Italy
| | - Peter Robatscher
- Laboratory for Flavours and Metabolites, Institute for Agricultural Chemistry and Food Quality, Laimburg Research Centre, Auer-Ora, Italy
| | - Urban Spitaler
- Entomology Group, Institute for Plant Health, Laimburg Research Centre, Auer-Ora, Italy
| | - Riccardo Favaro
- Faculty of Agricultural, Environmental and Food Sciences, Free University of Bozen-Bolzano, Bolzano, Italy
| | - Silvia Schmidt
- Entomology Group, Institute for Plant Health, Laimburg Research Centre, Auer-Ora, Italy
| | - Paul G Becher
- Department of Plant Protection Biology, Chemical Ecology Horticulture Unit, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Sergio Angeli
- Faculty of Agricultural, Environmental and Food Sciences, Free University of Bozen-Bolzano, Bolzano, Italy.
- Competence Centre for Plant Health, Free University of Bozen-Bolzano, Bolzano, Italy.
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Dzaki N, Alenius M. A cilia-bound unconventional secretory pathway for Drosophila odorant receptors. BMC Biol 2024; 22:84. [PMID: 38610043 PMCID: PMC11015608 DOI: 10.1186/s12915-024-01877-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 04/02/2024] [Indexed: 04/14/2024] Open
Abstract
BACKGROUND Post-translational transport is a vital process which ensures that each protein reaches its site of function. Though most do so via an ordered ER-to-Golgi route, an increasing number of proteins are now shown to bypass this conventional secretory pathway. RESULTS In the Drosophila olfactory sensory neurons (OSNs), odorant receptors (ORs) are trafficked from the ER towards the cilia. Here, we show that Or22a, a receptor of various esters and alcoholic compounds, reaches the cilia partially through unconventional means. Or22a frequently present as puncta at the somatic cell body exit and within the dendrite prior to the cilia base. These rarely coincide with markers of either the intermediary ER-Golgi-intermediate-compartment (ERGIC) or Golgi structures. ERGIC and Golgi also displayed axonal localization biases, a further indication that at least some measure of OR transport may occur independently of their involvement. Additionally, neither the loss of several COPII genes involved in anterograde trafficking nor ERGIC itself affected puncta formation or Or22a transport to the cilium. Instead, we observed the consistent colocalization of Or22a puncta with Grasp65, the sole Drosophila homolog of mammalian GRASP55/Grh1, a marker of the unconventional pathway. The numbers of both Or22a and Grasp65-positive puncta were furthermore increased upon nutritional starvation, a condition known to enhance Golgi-bypassing secretory activity. CONCLUSIONS Our results demonstrate an alternative route of Or22a transport, thus expanding the repertoire of unconventional secretion mechanisms in neurons.
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Affiliation(s)
- Najat Dzaki
- Department of Molecular Biology, Umeå University, Umeå, 901 87, SE, Sweden
| | - Mattias Alenius
- Department of Molecular Biology, Umeå University, Umeå, 901 87, SE, Sweden.
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Fang A, Yu CR. Activity-dependent formation of the topographic map and the critical period in the development of mammalian olfactory system. Genesis 2024; 62:e23586. [PMID: 38593162 PMCID: PMC11003738 DOI: 10.1002/dvg.23586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/03/2024] [Accepted: 01/05/2024] [Indexed: 04/11/2024]
Abstract
Neural activity influences every aspect of nervous system development. In olfactory systems, sensory neurons expressing the same odorant receptor project their axons to stereotypically positioned glomeruli, forming a spatial map of odorant receptors in the olfactory bulb. As individual odors activate unique combinations of glomeruli, this map forms the basis for encoding olfactory information. The establishment of this stereotypical olfactory map requires coordinated regulation of axon guidance molecules instructed by spontaneous activity. Recent studies show that sensory experiences also modify innervation patterns in the olfactory bulb, especially during a critical period of the olfactory system development. This review examines evidence in the field to suggest potential mechanisms by which various aspects of neural activity regulate axon targeting. We also discuss the precise functions served by neural plasticity during the critical period.
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Affiliation(s)
- Ai Fang
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - C. Ron Yu
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
- Department of Cell Biology and Physiology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
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Pacalon J, Audic G, Magnat J, Philip M, Golebiowski J, Moreau CJ, Topin J. Elucidation of the structural basis for ligand binding and translocation in conserved insect odorant receptor co-receptors. Nat Commun 2023; 14:8182. [PMID: 38081900 PMCID: PMC10713630 DOI: 10.1038/s41467-023-44058-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 11/28/2023] [Indexed: 12/18/2023] Open
Abstract
In numerous insects, the olfactory receptor family forms a unique class of heteromeric cation channels. Recent progress in resolving the odorant receptor structures offers unprecedented opportunities for deciphering their molecular mechanisms of ligand recognition. Unexpectedly, these structures in apo or ligand-bound states did not reveal the pathway taken by the ligands between the extracellular space and the deep internal cavities. By combining molecular modeling with electrophysiological recordings, we identified amino acids involved in the dynamic entry pathway and the binding of VUAA1 to Drosophila melanogaster's odorant receptor co-receptor (Orco). Our results provide evidence for the exact location of the agonist binding site and a detailed and original mechanism of ligand translocation controlled by a network of conserved residues. These findings would explain the particularly high selectivity of Orcos for their ligands.
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Affiliation(s)
- Jody Pacalon
- Université Côte d'Azur, Institut de Chimie de Nice UMR7272, CNRS, Nice, France
| | | | | | - Manon Philip
- Univ. Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
| | - Jérôme Golebiowski
- Department of Brain & Cognitive Sciences, DGIST, 333, Techno JungAng, Daero, HyeongPoong Myeon, Daegu, Republic of Korea
| | | | - Jérémie Topin
- Université Côte d'Azur, Institut de Chimie de Nice UMR7272, CNRS, Nice, France.
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Mariette J, Noël A, Louis T, Montagné N, Chertemps T, Jacquin-Joly E, Marion-Poll F, Sandoz JC. Transcuticular calcium imaging as a tool for the functional study of insect odorant receptors. Front Mol Neurosci 2023; 16:1182361. [PMID: 37645702 PMCID: PMC10461100 DOI: 10.3389/fnmol.2023.1182361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 07/12/2023] [Indexed: 08/31/2023] Open
Abstract
The primary actors in the detection of olfactory information in insects are odorant receptors (ORs), transmembrane proteins expressed at the dendrites of olfactory sensory neurons (OSNs). In order to decode the insect olfactome, many studies focus on the deorphanization of ORs (i.e., identification of their ligand), using various approaches involving heterologous expression coupled to neurophysiological recordings. The "empty neuron system" of the fruit fly Drosophila melanogaster is an appreciable host for insect ORs, because it conserves the cellular environment of an OSN. Neural activity is usually recorded using labor-intensive electrophysiological approaches (single sensillum recordings, SSR). In this study, we establish a simple method for OR deorphanization using transcuticular calcium imaging (TCI) at the level of the fly antenna. As a proof of concept, we used two previously deorphanized ORs from the cotton leafworm Spodoptera littoralis, a specialist pheromone receptor and a generalist plant odor receptor. We demonstrate that by co-expressing the GCaMP6s/m calcium probes with the OR of interest, it is possible to measure robust odorant-induced responses under conventional microscopy conditions. The tuning breadth and sensitivity of ORs as revealed using TCI were similar to those measured using single sensillum recordings (SSR). We test and discuss the practical advantages of this method in terms of recording duration and the simultaneous testing of several insects.
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Affiliation(s)
- Julia Mariette
- Evolution, Genomes, Behaviour and Ecology, IDEEV, CNRS, Université Paris-Saclay, IRD, Gif-sur-Yvette, France
| | - Amélie Noël
- Evolution, Genomes, Behaviour and Ecology, IDEEV, CNRS, Université Paris-Saclay, IRD, Gif-sur-Yvette, France
| | - Thierry Louis
- Evolution, Genomes, Behaviour and Ecology, IDEEV, CNRS, Université Paris-Saclay, IRD, Gif-sur-Yvette, France
| | - Nicolas Montagné
- Sorbonne Université, INRAE, CNRS, IRD, UPEC, Université Paris Cité, Institute of Ecology and Environmental Sciences of Paris (iEES-Paris), Paris, France
| | - Thomas Chertemps
- Sorbonne Université, INRAE, CNRS, IRD, UPEC, Université Paris Cité, Institute of Ecology and Environmental Sciences of Paris (iEES-Paris), Paris, France
| | - Emmanuelle Jacquin-Joly
- Sorbonne Université, INRAE, CNRS, IRD, UPEC, Université Paris Cité, Institute of Ecology and Environmental Sciences of Paris (iEES-Paris), Paris, France
| | - Frédéric Marion-Poll
- Evolution, Genomes, Behaviour and Ecology, IDEEV, CNRS, Université Paris-Saclay, IRD, Gif-sur-Yvette, France
| | - Jean-Christophe Sandoz
- Evolution, Genomes, Behaviour and Ecology, IDEEV, CNRS, Université Paris-Saclay, IRD, Gif-sur-Yvette, France
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Zhang Y, Wang B, Zhou Y, Liao M, Sheng C, Cao H, Gao Q. Identification and characterization of odorant receptors in Plutella xylostella antenna response to 2,3-dimethyl-6-(1-hydroxy)-pyrazine. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2023; 194:105523. [PMID: 37532335 DOI: 10.1016/j.pestbp.2023.105523] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/26/2023] [Accepted: 07/06/2023] [Indexed: 08/04/2023]
Abstract
Diamondback moth (Plutella xylostella), a worldwide migratory pest that is developing strong resistance to various chemical insecticides. It has been determined that four natural pyrazines isolated from Allium tuberosum showed significant repellent activity to P. xylostella, but the molecular target still unknown. In the present study, a novel synthetic route for 2,3-dimethyl-6-(1-hydroxy)-pyrazine which has the most significant repellent activity with a purity of 90.60% was established. Simultaneously, the bioassay result declared that the repellent grade was IV at a dosage of 0.01 mg which was the same as to the published data. Transcriptomics analysis detected 1643 upregulated and 3837 downregulated genes in P. xylostella antennae following this pyrazine exposure. Then, 2142 differentially expressed genes were annotated using Gene Ontology and 2757 genes were annotated by Kyoto Encyclopedia of Genes and Genomes. Moreover, this procedure identified 84 odour perception-related genes, 58 odorant receptor (OR) genes including 57 conventional ORs and the odorant receptor co-receptor (Orco, atypical odorant receptor) gene, and 26 odorant-binding protein (OBP) genes. Based on quantitative real time PCR (RT-qPCR) and differential expression results, 9 OR genes including the Orco were cloned and characterised. In summary, this study provides important basis for the utilization of pyrazines as the main active ingredients or lead compounds to developing new botanical pesticides, which will reduce application of chemical pesticides and postpone the development of resistance.
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Affiliation(s)
- Yongjie Zhang
- Anhui Province Engineering Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, 230036 Hefei, China; Anhui Province Key Laboratory of Crop Integrated Pest Management, School of Plant Protection, Anhui Agricultural University, 230036 Hefei, China
| | - Buguo Wang
- Anhui Province Engineering Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, 230036 Hefei, China; Anhui Province Key Laboratory of Crop Integrated Pest Management, School of Plant Protection, Anhui Agricultural University, 230036 Hefei, China
| | - Yeping Zhou
- Anhui Province Engineering Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, 230036 Hefei, China; Anhui Province Key Laboratory of Crop Integrated Pest Management, School of Plant Protection, Anhui Agricultural University, 230036 Hefei, China
| | - Min Liao
- Anhui Province Engineering Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, 230036 Hefei, China; Anhui Province Key Laboratory of Crop Integrated Pest Management, School of Plant Protection, Anhui Agricultural University, 230036 Hefei, China
| | - Chengwang Sheng
- Anhui Province Engineering Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, 230036 Hefei, China; Anhui Province Key Laboratory of Crop Integrated Pest Management, School of Plant Protection, Anhui Agricultural University, 230036 Hefei, China
| | - Haiqun Cao
- Anhui Province Engineering Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, 230036 Hefei, China; Anhui Province Key Laboratory of Crop Integrated Pest Management, School of Plant Protection, Anhui Agricultural University, 230036 Hefei, China
| | - Quan Gao
- Anhui Province Engineering Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, 230036 Hefei, China; Anhui Province Key Laboratory of Crop Integrated Pest Management, School of Plant Protection, Anhui Agricultural University, 230036 Hefei, China.
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12
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Tatarko AR, Leonard AS, Mathew D. A neonicotinoid pesticide alters Drosophila olfactory processing. Sci Rep 2023; 13:10606. [PMID: 37391495 PMCID: PMC10313779 DOI: 10.1038/s41598-023-37589-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 06/23/2023] [Indexed: 07/02/2023] Open
Abstract
Neonicotinoid pesticides are well-known for their sublethal effects on insect behavior and physiology. Recent work suggests neonicotinoids can impair insect olfactory processing, with potential downstream effects on behavior and possibly survival. However, it is unclear whether impairment occurs during peripheral olfactory detection, during information processing in central brain regions, or in both contexts. We used Drosophila melanogaster to explore the potential for neonicotinoids to disrupt olfaction by conducting electrophysiological analyses of single neurons and whole antennae of flies exposed to varying concentrations of the neonicotinoid imidacloprid (IMD) that were shown to cause relative differences in fly survival. Our results demonstrated that IMD exposure significantly reduced the activity of a single focal olfactory neuron and delayed the return to baseline activity of the whole antenna. To determine if IMD also impacts olfactory-guided behavior, we compared flies' relative preference for odor sources varying in ethanol content. Flies exposed to IMD had a greater relative preference for ethanol-laced pineapple juice than control flies, demonstrating that neuronal shifts induced by IMD that we observed are associated with changes in relative preference. Given the interest in the sensory impacts of agrochemical exposure on wild insect behavior and physiology, we highlight the potential of Drosophila as a tractable model for investigating the effects of pesticides at scales ranging from single-neuron physiology to olfactory-guided behavior.
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Affiliation(s)
- Anna R Tatarko
- Department of Biology, University of Nevada-Reno, Reno, NV, 89557, USA.
| | - Anne S Leonard
- Department of Biology, University of Nevada-Reno, Reno, NV, 89557, USA
| | - Dennis Mathew
- Department of Biology, University of Nevada-Reno, Reno, NV, 89557, USA
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13
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Prelic S, Getahun MN, Kaltofen S, Hansson BS, Wicher D. Modulation of the NO-cGMP pathway has no effect on olfactory responses in the Drosophila antenna. Front Cell Neurosci 2023; 17:1180798. [PMID: 37305438 PMCID: PMC10248080 DOI: 10.3389/fncel.2023.1180798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 05/02/2023] [Indexed: 06/13/2023] Open
Abstract
Olfaction is a crucial sensory modality in insects and is underpinned by odor-sensitive sensory neurons expressing odorant receptors that function in the dendrites as odorant-gated ion channels. Along with expression, trafficking, and receptor complexing, the regulation of odorant receptor function is paramount to ensure the extraordinary sensory abilities of insects. However, the full extent of regulation of sensory neuron activity remains to be elucidated. For instance, our understanding of the intracellular effectors that mediate signaling pathways within antennal cells is incomplete within the context of olfaction in vivo. Here, with the use of optical and electrophysiological techniques in live antennal tissue, we investigate whether nitric oxide signaling occurs in the sensory periphery of Drosophila. To answer this, we first query antennal transcriptomic datasets to demonstrate the presence of nitric oxide signaling machinery in antennal tissue. Next, by applying various modulators of the NO-cGMP pathway in open antennal preparations, we show that olfactory responses are unaffected by a wide panel of NO-cGMP pathway inhibitors and activators over short and long timescales. We further examine the action of cAMP and cGMP, cyclic nucleotides previously linked to olfactory processes as intracellular potentiators of receptor functioning, and find that both long-term and short-term applications or microinjections of cGMP have no effect on olfactory responses in vivo as measured by calcium imaging and single sensillum recording. The absence of the effect of cGMP is shown in contrast to cAMP, which elicits increased responses when perfused shortly before olfactory responses in OSNs. Taken together, the apparent absence of nitric oxide signaling in olfactory neurons indicates that this gaseous messenger may play no role as a regulator of olfactory transduction in insects, though may play other physiological roles at the sensory periphery of the antenna.
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Affiliation(s)
- Sinisa Prelic
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Merid N. Getahun
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Sabine Kaltofen
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Bill S. Hansson
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Dieter Wicher
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
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14
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Chang H, Cassau S, Krieger J, Guo X, Knaden M, Kang L, Hansson BS. A chemical defense deters cannibalism in migratory locusts. Science 2023; 380:537-543. [PMID: 37141362 DOI: 10.1126/science.ade6155] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Many animals engage in cannibalism to supplement their diets. Among dense populations of migratory locusts, cannibalism is prevalent. We show that under crowded conditions, locusts produce an anticannibalistic pheromone called phenylacetonitrile. Both the degree of cannibalism and the production of phenylacetonitrile are density dependent and covary. We identified the olfactory receptor that detects phenylacetonitrile and used genome editing to make this receptor nonfunctional, thereby abolishing the negative behavioral response. We also inactivated the gene underlying phenylacetonitrile production and show that locusts that lack this compound lose its protection and are more frequently exposed to intraspecific predation. Thus, we reveal an anticannibalistic feature built on a specifically produced odor. The system is very likely to be of major importance in locust population ecology, and our results might therefore provide opportunities in locust management.
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Affiliation(s)
- Hetan Chang
- Department of Evolutionary Ecology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Sina Cassau
- Department of Animal Physiology, Martin-Luther-Universitat Halle-Wittenberg, Halle (Saale), Germany
| | - Jürgen Krieger
- Department of Animal Physiology, Martin-Luther-Universitat Halle-Wittenberg, Halle (Saale), Germany
| | - Xiaojiao Guo
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, P. R. China
| | - Markus Knaden
- Department of Evolutionary Ecology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Le Kang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, P. R. China
| | - Bill S Hansson
- Department of Evolutionary Ecology, Max Planck Institute for Chemical Ecology, Jena, Germany
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15
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Lv M, Xu X, Zhang X, Yuwen B, Zhang L. Serotonin/GABA receptors modulate odor input to olfactory receptor neuron in locusts. Front Cell Neurosci 2023; 17:1156144. [PMID: 37187607 PMCID: PMC10175586 DOI: 10.3389/fncel.2023.1156144] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 03/27/2023] [Indexed: 05/17/2023] Open
Abstract
Introduction Serotonin (5-hydroxytryptamine; 5-HT) and GABA (γ-aminobutyric acid) are involved in the regulation of behaviors in the central nervous system. However, it remains unclear whether they modulate olfaction in the peripheral nervous system, and how they modulate olfaction. Methods and results One 5-HT receptor sequence (Lmig5-HT2) and one GABA receptor sequence (LmigGABAb) were identified in locust antennae by transcriptome analysis and polymerase chain reaction experiments. In situ hybridization localized Lmig5-HT2 to accessory cells, while LmigGABAb was localized to olfactory receptor neurons (ORNs) in locust chemosensilla. Single-unit electrophysiological recordings combined with RNA interference (RNAi) experiments indicated ORNs of locusts with knockdown of Lmig5-HT2 (ds-Lmig5-HT2) and LmigGABAb (ds-LmigGABAb) to some odors had significantly higher responses than wild-type and control locusts in the dose-dependent responses. Moreover, the gaps between the responses of ORNs of RNAi ones and those of wild-type and ds-GFP enlarged with an increase in concentrations of odors. Discussion Taken together, our findings suggest that 5-HT, GABA, and their receptors exist in the insect peripheral nervous system and that they may function as negative feedback to ORNs and contribute to a fine-tuning mechanism for olfaction in the peripheral nervous system.
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Affiliation(s)
- Mingyue Lv
- Department of Agricultural Insects and Pest Control, China Agricultural University, Beijing, China
| | - Xiao Xu
- Department of Agricultural Insects and Pest Control, China Agricultural University, Beijing, China
| | - Xinyang Zhang
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Bo Yuwen
- Department of Agricultural Insects and Pest Control, China Agricultural University, Beijing, China
| | - Long Zhang
- Department of Agricultural Insects and Pest Control, China Agricultural University, Beijing, China
- Plant Protection Institute, Shandong Provincial Engineering Technology Research Center on Biocontrol for Pests, Jinan, China
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16
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Benton R, Dahanukar A. Chemosensory Coding in Drosophila Single Sensilla. Cold Spring Harb Protoc 2023; 2023:107803-pdb.top. [PMID: 36446528 DOI: 10.1101/pdb.top107803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The chemical senses-smell and taste-detect and discriminate an enormous diversity of environmental stimuli and provide fascinating but challenging models to investigate how sensory cues are represented in the brain. Important stimulus-coding events occur in peripheral sensory neurons, which express specific combinations of chemosensory receptors with defined ligand-response profiles. These receptors convert ligand recognition into spatial and temporal patterns of neural activity that are transmitted to, and interpreted in, central brain regions. Drosophila melanogaster provides an attractive model to study chemosensory coding because it possesses relatively simple peripheral olfactory and gustatory systems that display many organizational parallels to those of vertebrates. Moreover, nearly all peripheral chemosensory neurons have been molecularly characterized and are accessible for physiological analysis, as they are exposed on the surface of sensory organs housed in specialized hairs called sensilla. Here, we briefly review anatomical, molecular, and physiological properties of adult Drosophila olfactory and gustatory systems and provide background to methods for electrophysiological recordings of ligand-evoked activity from different types of chemosensory sensilla.
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Affiliation(s)
- Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Anupama Dahanukar
- Department of Molecular, Cell & Systems Biology, University of California, Riverside, California 92521, USA
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17
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Benton R, Dahanukar A. Recording from Fly Olfactory Sensilla. Cold Spring Harb Protoc 2023; 2023:108063-pdb.prot. [PMID: 36446530 DOI: 10.1101/pdb.prot108063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Abstract
Olfactory systems detect and discriminate an enormous diversity of volatile environmental stimuli and provide important paradigms to investigate how sensory cues are represented in the brain. Key stimulus-coding events occur in peripheral olfactory sensory neurons, which typically express a single olfactory receptor-from a large repertoire encoded in the genome-with a defined ligand-response profile. These receptors convert odor ligand recognition into spatial and temporal patterns of neural activity that are transmitted to, and interpreted in, central brain regions. Drosophila provides an attractive model to study olfactory coding because it possesses a relatively simple peripheral olfactory system that displays many organizational parallels to those of vertebrates. Moreover, nearly all olfactory sensory neurons have been molecularly characterized and are accessible for physiological analysis, as they are exposed on the surface of sensory organs (antennae and maxillary palps) housed in specialized hairs called sensilla. This protocol describes how to perform recordings of odor-evoked activity from Drosophila olfactory sensilla, covering the basics of sample preparation, setting up the electrophysiology rig, assembling an odor stimulus-delivery device, and data analysis. The methodology can be used to characterize the ligand-recognition properties of most olfactory sensory neurons and the role of olfactory receptors (and other molecular components) in signal transduction.
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Affiliation(s)
- Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Anupama Dahanukar
- Department of Molecular, Cell & Systems Biology, University of California, Riverside, California 92521, USA
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18
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Boronat-Garcia A, Iben J, Dominguez-Martin E, Stopfer M. Identification and analysis of odorant receptors expressed in the two main olfactory organs, antennae and palps, of Schistocerca americana. Sci Rep 2022; 12:22628. [PMID: 36587060 PMCID: PMC9805433 DOI: 10.1038/s41598-022-27199-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 12/28/2022] [Indexed: 01/01/2023] Open
Abstract
Locusts depend upon their sense of smell and provide useful models for understanding olfaction. Extending this understanding requires knowledge of the molecular and structural organization of the olfactory system. Odor sensing begins with olfactory receptor neurons (ORNs), which express odorant receptors (ORs). In insects, ORNs are housed, in varying numbers, in olfactory sensilla. Because the organization of ORs within sensilla affects their function, it is essential to identify the ORs they contain. Here, using RNA sequencing, we identified 179 putative ORs in the transcriptomes of the two main olfactory organs, antenna and palp, of the locust Schistocerca americana. Quantitative expression analysis showed most putative ORs (140) are expressed in antennae while only 31 are in the palps. Further, our analysis identified one OR detected only in the palps and seven ORs that are expressed differentially by sex. An in situ analysis of OR expression suggested ORs are organized in non-random combinations within antennal sensilla. A phylogenetic comparison of OR predicted protein sequences revealed homologous relationships among two other Acrididae species. Our results provide a foundation for understanding the organization of the first stage of the olfactory system in S. americana, a well-studied model for olfactory processing.
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Affiliation(s)
- Alejandra Boronat-Garcia
- grid.420089.70000 0000 9635 8082Section on Sensory Coding and Neural Ensembles, National Institutes of Health, Eunice Kennedy Shriver National Institute of Child and Human Development, Bethesda, MD USA
| | - James Iben
- grid.420089.70000 0000 9635 8082Molecular and Genomics Core, National Institutes of Health, Eunice Kennedy Shriver National Institute of Child and Human Development, Bethesda, MD USA
| | - Eunice Dominguez-Martin
- grid.416870.c0000 0001 2177 357XBiochemistry Section, National Institutes of Health, National Institute of Neurological Disorders and Stroke, Bethesda, MD USA
| | - Mark Stopfer
- grid.420089.70000 0000 9635 8082Section on Sensory Coding and Neural Ensembles, National Institutes of Health, Eunice Kennedy Shriver National Institute of Child and Human Development, Bethesda, MD USA
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19
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Abstract
Among the many wonders of nature, the sense of smell of the fly Drosophila melanogaster might seem, at first glance, of esoteric interest. Nevertheless, for over a century, the 'nose' of this insect has been an extraordinary system to explore questions in animal behaviour, ecology and evolution, neuroscience, physiology and molecular genetics. The insights gained are relevant for our understanding of the sensory biology of vertebrates, including humans, and other insect species, encompassing those detrimental to human health. Here, I present an overview of our current knowledge of D. melanogaster olfaction, from molecules to behaviours, with an emphasis on the historical motivations of studies and illustration of how technical innovations have enabled advances. I also highlight some of the pressing and long-term questions.
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Affiliation(s)
- Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
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20
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Tadres D, Wong PH, To T, Moehlis J, Louis M. Depolarization block in olfactory sensory neurons expands the dimensionality of odor encoding. SCIENCE ADVANCES 2022; 8:eade7209. [PMID: 36525486 PMCID: PMC9757753 DOI: 10.1126/sciadv.ade7209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 11/15/2022] [Indexed: 05/20/2023]
Abstract
Upon strong and prolonged excitation, neurons can undergo a silent state called depolarization block that is often associated with disorders such as epileptic seizures. Here, we show that neurons in the peripheral olfactory system undergo depolarization block as part of their normal physiological function. Typically, olfactory sensory neurons enter depolarization block at odor concentrations three orders of magnitude above their detection threshold, thereby defining receptive fields over concentration bands. The silencing of high-affinity olfactory sensory neurons produces sparser peripheral odor representations at high-odor concentrations, which might facilitate perceptual discrimination. Using a conductance-based model of the olfactory transduction cascade paired with spike generation, we provide numerical and experimental evidence that depolarization block arises from the slow inactivation of sodium channels-a process that could affect a variety of sensory neurons. The existence of ethologically relevant depolarization block in olfactory sensory neurons creates an additional dimension that expands the peripheral encoding of odors.
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Affiliation(s)
- David Tadres
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA, USA
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Philip H. Wong
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA, USA
- Department of Mechanical Engineering, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Thuc To
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Jeff Moehlis
- Department of Mechanical Engineering, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Matthieu Louis
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA, USA
- Department of Physics, University of California, Santa Barbara, Santa Barbara, CA, USA
- Corresponding author.
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21
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Ikeda K, Kataoka M, Tanaka NK. Nonsynaptic Transmission Mediates Light Context-Dependent Odor Responses in Drosophila melanogaster. J Neurosci 2022; 42:8621-8628. [PMID: 36180227 PMCID: PMC9671575 DOI: 10.1523/jneurosci.1106-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 09/23/2022] [Accepted: 09/26/2022] [Indexed: 11/21/2022] Open
Abstract
Recent connectome analyses of the entire synaptic circuit in the nervous system have provided tremendous insights into how neural processing occurs through the synaptic relay of neural information. Conversely, the extent to which ephaptic transmission which does not depend on the synapses contributes to the relay of neural information, especially beyond a distance between adjacent neurons and to neural processing remains unclear. We show that ephaptic transmission mediated by extracellular potential changes in female Drosophila melanogaster can reach >200 µm, equivalent to the depth of its brain. Furthermore, ephaptic transmission driven by retinal photoreceptor cells mediates light-evoked firing rate increases in olfactory sensory neurons. These results indicate that ephaptic transmission contributes to sensory responses that can change momentarily in a context-dependent manner.SIGNIFICANCE STATEMENT Although extracellular field potential activities are commonly observed in many nervous systems, this activity has been generally considered as a side effect of synchronized spiking of neurons. This study, however, shows that field potential changes in retinae evoked by a sensory stimulus can control the excitability of distant neurons in vivo and mediates multimodal sensory integration in Drosophila melanogaster As such ephaptic transmission is more effective at a short distance, the ephaptic transmission from the retinae may contribute significantly to firing rate changes in downstream neurons of the photoreceptor cells in the optic lobe.
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Affiliation(s)
- Kazuaki Ikeda
- Division of Biology, Department of Biological Sciences, School of Science, Hokkaido University, Sapporo, 060-0810, Japan
- Graduate School of Life Sciences, Hokkaido University, Sapporo, 060-0810, Japan
| | - Masaki Kataoka
- Division of Biology, Department of Biological Sciences, School of Science, Hokkaido University, Sapporo, 060-0810, Japan
- Graduate School of Life Sciences, Hokkaido University, Sapporo, 060-0810, Japan
| | - Nobuaki K Tanaka
- Division of Biology, Department of Biological Sciences, School of Science, Hokkaido University, Sapporo, 060-0810, Japan
- Graduate School of Life Sciences, Hokkaido University, Sapporo, 060-0810, Japan
- Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan
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22
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Scalzotto M, Ng R, Cruchet S, Saina M, Armida J, Su CY, Benton R. Pheromone sensing in Drosophila requires support cell-expressed Osiris 8. BMC Biol 2022; 20:230. [PMID: 36217142 PMCID: PMC9552441 DOI: 10.1186/s12915-022-01425-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 09/29/2022] [Indexed: 11/16/2022] Open
Abstract
Background The nose of most animals comprises multiple sensory subsystems, which are defined by the expression of different olfactory receptor families. Drosophila melanogaster antennae contain two morphologically and functionally distinct subsystems that express odorant receptors (Ors) or ionotropic receptors (Irs). Although these receptors have been thoroughly characterized in this species, the subsystem-specific expression and roles of other genes are much less well-understood. Results Here we generate subsystem-specific transcriptomic datasets to identify hundreds of genes, encoding diverse protein classes, that are selectively enriched in either Or or Ir subsystems. Using single-cell antennal transcriptomic data and RNA in situ hybridization, we find that most neuronal genes—other than sensory receptor genes—are broadly expressed within the subsystems. By contrast, we identify many non-neuronal genes that exhibit highly selective expression, revealing substantial molecular heterogeneity in the non-neuronal cellular components of the olfactory subsystems. We characterize one Or subsystem-specific non-neuronal molecule, Osiris 8 (Osi8), a conserved member of a large, insect-specific family of transmembrane proteins. Osi8 is expressed in the membranes of tormogen support cells of pheromone-sensing trichoid sensilla. Loss of Osi8 does not have obvious impact on trichoid sensillar development or basal neuronal activity, but abolishes high sensitivity responses to pheromone ligands. Conclusions This work identifies a new protein required for insect pheromone detection, emphasizes the importance of support cells in neuronal sensory functions, and provides a resource for future characterization of other olfactory subsystem-specific genes. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01425-w.
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Affiliation(s)
- Marta Scalzotto
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Renny Ng
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Steeve Cruchet
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Michael Saina
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Jan Armida
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Chih-Ying Su
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland.
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23
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Fan XB, Mo BT, Li GC, Huang LQ, Guo H, Gong XL, Wang CZ. Mutagenesis of the odorant receptor co-receptor (Orco) reveals severe olfactory defects in the crop pest moth Helicoverpa armigera. BMC Biol 2022; 20:214. [PMID: 36175945 PMCID: PMC9524114 DOI: 10.1186/s12915-022-01411-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 09/16/2022] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Odorant receptors (ORs) as odorant-gated ion channels play a crucial role in insect olfaction. They are formed by a heteromultimeric complex of the odorant receptor co-receptor (Orco) and a ligand-selective Or. Other types of olfactory receptor proteins, such as ionotropic receptors (IRs) and some gustatory receptors (GRs), are also involved in the olfactory system of insects. Orco as an obligatory subunit of ORs is highly conserved, providing an opportunity to systematically evaluate OR-dependent olfactory responses. RESULTS Herein, we successfully established a homozygous mutant (Orco-/-) of Helicoverpa armigera, a notorious crop pest, using the CRISPR/Cas9 gene editing technique. We then compared the olfactory response characteristics of wild type (WT) and Orco-/- adults and larvae. Orco-/- males were infertile, while Orco-/- females were fertile. The lifespan of Orco-/- females was longer than that of WT females. The expressions of most Ors, Irs, and other olfaction-related genes in adult antennae of Orco-/- moths were not obviously affected, but some of them were up- or down-regulated. In addition, there was no change in the neuroanatomical phenotype of Orco-/- moths at the level of the antennal lobe (including the macroglomerular complex region of the male). Using EAG and SSR techniques, we discovered that electrophysiological responses of Orco-/- moths to sex pheromone components and many host plant odorants were absent. The upwind flight behaviors toward sex pheromones of Orco-/- males were severely reduced in a wind tunnel experiment. The oviposition selectivity of Orco-/- females to the host plant (green pepper) has completely disappeared, and the chemotaxis toward green pepper was also lost in Orco-/- larvae. CONCLUSIONS Our study indicates that OR-mediated olfaction is essential for pheromone communication, oviposition selection, and larval chemotaxis of H. armigera, suggesting a strategy in which mate searching and host-seeking behaviors of moth pests could be disrupted by inhibiting or silencing Orco expression.
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Affiliation(s)
- Xiao-Bin Fan
- grid.9227.e0000000119573309State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing, 100101 People’s Republic of China ,grid.410726.60000 0004 1797 8419CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Bao-Tong Mo
- grid.9227.e0000000119573309State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing, 100101 People’s Republic of China ,grid.410726.60000 0004 1797 8419CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Guo-Cheng Li
- grid.9227.e0000000119573309State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing, 100101 People’s Republic of China ,grid.410726.60000 0004 1797 8419CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Ling-Qiao Huang
- grid.9227.e0000000119573309State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing, 100101 People’s Republic of China
| | - Hao Guo
- grid.9227.e0000000119573309State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing, 100101 People’s Republic of China ,grid.410726.60000 0004 1797 8419CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Xin-Lin Gong
- grid.9227.e0000000119573309State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing, 100101 People’s Republic of China ,grid.410726.60000 0004 1797 8419CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - Chen-Zhu Wang
- grid.9227.e0000000119573309State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing, 100101 People’s Republic of China ,grid.410726.60000 0004 1797 8419CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, People’s Republic of China
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Au DD, Foden AJ, Park SJ, Nguyen TH, Liu JC, Tran MD, Jaime OG, Yu Z, Holmes TC. Mosquito cryptochromes expressed in Drosophila confer species-specific behavioral light responses. Curr Biol 2022; 32:3731-3744.e4. [PMID: 35914532 PMCID: PMC9810238 DOI: 10.1016/j.cub.2022.07.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 04/28/2022] [Accepted: 07/08/2022] [Indexed: 01/07/2023]
Abstract
Cryptochrome (CRY) is a short-wavelength light-sensitive photoreceptor expressed in a subset of circadian neurons and eyes in Drosophila that regulates light-evoked circadian clock resetting. Acutely, light evokes rapid electrical excitation of the ventral lateral subset of circadian neurons and confers circadian-modulated avoidance behavioral responses to short-wavelength light. Recent work shows dramatically different avoidance versus attraction behavioral responses to short-wavelength light in day-active versus night-active mosquitoes and that these behavioral responses are attenuated by CRY protein degradation by constant light exposure in mosquitoes. To determine whether CRY1s mediate species-specific coding for behavioral and electrophysiological light responses, we used an "empty neuron" approach and transgenically expressed diurnal Aedes aegypti (AeCRY1) versus nocturnal Anopheles gambiae (AgCRY1) in a cry-null Drosophila background. AeCRY1 is much less light sensitive than either AgCRY1 or DmCRY as shown by partial behavioral rhythmicity following constant light exposure. Remarkably, expression of nocturnal AgCRY1 confers low survival to constant white light as does expression of AeCRY1 to a lesser extent. AgCRY1 mediates significantly stronger electrophysiological cell-autonomous responses to 365 nm ultraviolet (UV) light relative to AeCRY1. AgCRY1 expression mediates electrophysiological sensitivity to 635 nm red light, whereas AeCRY1 does not, consistent with species-specific mosquito red light responses. AgCRY1 and DmCRY mediate intensity-dependent avoidance behavior to UV light at different light intensity thresholds, whereas AeCRY1 does not, thus mimicking mosquito and fly behaviors. These findings highlight CRY as a key non-image-forming visual photoreceptor that mediates physiological and behavioral light responses in a species-specific fashion.
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Affiliation(s)
- David D Au
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA 92697, USA
| | - Alexander J Foden
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA 92697, USA
| | - Soo Jee Park
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA 92697, USA
| | - Thanh H Nguyen
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA 92697, USA
| | - Jenny C Liu
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA 92697, USA
| | - Mary D Tran
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA 92697, USA
| | - Olga G Jaime
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA 92697, USA
| | - Zhaoxia Yu
- Department of Statistics, Donald Bren School of Information and Computer Sciences, University of California, Irvine, Irvine, CA 92697, USA; Center for Neural Circuit Mapping, University of California, Irvine, Irvine, CA 92697, USA
| | - Todd C Holmes
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA 92697, USA; Center for Neural Circuit Mapping, University of California, Irvine, Irvine, CA 92697, USA.
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25
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Zhang R, Li LS, Rao B, Rong H, Sun MY, Yao J, Chen R, Zhou Q, Mennerick S, Raman B, Wang LV. Multiscale photoacoustic tomography of neural activities with GCaMP calcium indicators. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:JBO-220087GR. [PMID: 36088528 PMCID: PMC9463545 DOI: 10.1117/1.jbo.27.9.096004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 08/24/2022] [Indexed: 06/15/2023]
Abstract
SIGNIFICANCE Optical imaging of responses in fluorescently labeled neurons has progressed significantly in recent years. However, there is still a need to monitor neural activities at divergent spatial scales and at depths beyond the optical diffusion limit. AIM To meet these needs, we aim to develop multiscale photoacoustic tomography (PAT) to image neural activities across spatial scales with a genetically encoded calcium indicator GCaMP. APPROACH First, using photoacoustic microscopy, we show that depth-resolved GCaMP signals can be monitored in vivo from a fly brain in response to odor stimulation without depth scanning and even with the cuticle intact. In vivo monitoring of GCaMP signals was also demonstrated in mouse brains. Next, using photoacoustic computed tomography, we imaged neural responses of a mouse brain slice at depths beyond the optical diffusion limit. RESULTS We provide the first unambiguous demonstration that multiscale PAT can be used to record neural activities in transgenic flies and mice with select neurons expressing GCaMP. CONCLUSIONS Our results indicate that the combination of multiscale PAT and fluorescent neural activity indicators provides a methodology for imaging targeted neurons at various scales.
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Affiliation(s)
- Ruiying Zhang
- Washington University in Saint Louis, Department of Biomedical Engineering, Saint Louis, Missouri, United States
| | - Lei S. Li
- California Institute of Technology, Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
| | - Bin Rao
- Washington University in Saint Louis, Department of Biomedical Engineering, Saint Louis, Missouri, United States
| | - Haoyang Rong
- Washington University in Saint Louis, Department of Biomedical Engineering, Saint Louis, Missouri, United States
| | - Min-Yu Sun
- Washington University School of Medicine, Department of Psychiatry, Saint Louis, Missouri, United States
| | - Junjie Yao
- Washington University in Saint Louis, Department of Biomedical Engineering, Saint Louis, Missouri, United States
| | - Ruimin Chen
- University of Southern California, Department of Biomedical Engineering, Los Angeles, California, United States
| | - Qifa Zhou
- University of Southern California, Department of Biomedical Engineering, Los Angeles, California, United States
| | - Steven Mennerick
- Washington University School of Medicine, Department of Psychiatry, Saint Louis, Missouri, United States
| | - Baranidharan Raman
- Washington University in Saint Louis, Department of Biomedical Engineering, Saint Louis, Missouri, United States
| | - Lihong V. Wang
- California Institute of Technology, Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
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26
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Copy number changes in co-expressed odorant receptor genes enable selection for sensory differences in drosophilid species. Nat Ecol Evol 2022; 6:1343-1353. [PMID: 35864227 DOI: 10.1038/s41559-022-01830-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 06/15/2022] [Indexed: 11/09/2022]
Abstract
Despite numerous examples of chemoreceptor gene family expansions and contractions, how these relate to modifications in the sensory neuron populations in which they are expressed remains unclear. Drosophila melanogaster's odorant receptor (Or) family is ideal for addressing this question because most Ors are expressed in distinct olfactory sensory neuron (OSN) types. Between-species changes in Or copy number may therefore indicate increases or reductions in the number of OSN populations. Here we investigated the Or67a subfamily, which exhibits copy number variation in D. melanogaster and its closest relatives: D. simulans, D. sechellia and D. mauritiana. These species' common ancestor had three Or67a paralogues that had already diverged adaptively. Following speciation, two Or67a paralogues were lost independently in D. melanogaster and D. sechellia, with ongoing positive selection shaping the intact genes. Unexpectedly, the functionally diverged Or67a paralogues in D. simulans are co-expressed in a single neuron population, which projects to a glomerulus homologous to that innervated by Or67a neurons in D. melanogaster. Thus, while sensory pathway neuroanatomy is conserved, independent selection on co-expressed receptors has contributed to species-specific peripheral coding. This work reveals a type of adaptive change largely overlooked for olfactory evolution, raising the possibility that similar processes influence other cases of insect Or co-expression.
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27
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Fleischer J, Rausch A, Dietze K, Erler S, Cassau S, Krieger J. A small number of male-biased candidate pheromone receptors are expressed in large subsets of the olfactory sensory neurons in the antennae of drones from the European honey bee Apis mellifera. INSECT SCIENCE 2022; 29:749-766. [PMID: 34346151 DOI: 10.1111/1744-7917.12960] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/21/2021] [Accepted: 07/29/2021] [Indexed: 06/13/2023]
Abstract
In the European honey bee (Apis mellifera), the olfactory system is essential for foraging and intraspecific communication via pheromones. Honey bees are equipped with a large repertoire of olfactory receptors belonging to the insect odorant receptor (OR) family. Previous studies have indicated that the transcription level of a few OR types including OR11, a receptor activated by the queen-released pheromone compound (2E)-9-oxodecenoic acid (9-ODA), is significantly higher in the antenna of males (drones) than in female workers. However, the number and distribution of antennal cells expressing male-biased ORs is elusive. Here, we analyzed antennal sections from bees by in situ hybridization for the expression of the male-biased receptors OR11, OR18, and OR170. Our results demonstrate that these receptors are expressed in only moderate numbers of cells in the antennae of females (workers and queens), whereas substantially higher cell numbers express these ORs in drones. Thus, the reported male-biased transcript levels are due to sex-specific differences in the number of antennal cells expressing these receptors. Detailed analyses for OR11 and OR18 in drone antennae revealed expression in two distinct subsets of olfactory sensory neurons (OSNs) that in total account for approximately 69% of the OR-positive cells. Such high percentages of OSNs expressing given receptors are reminiscent of male-biased ORs in moths that mediate the detection of female-released sex pheromone components. Collectively, our findings indicate remarkable similarities between male antennae of bees and moths and support the concept that male-biased ORs in bee drones serve the detection of female-emitted sex pheromones.
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Affiliation(s)
- Joerg Fleischer
- Martin Luther University Halle-Wittenberg, Institute of Biology/Zoology, Department of Animal Physiology, Halle (Saale)
| | - Alexander Rausch
- Martin Luther University Halle-Wittenberg, Institute of Biology/Zoology, Department of Animal Physiology, Halle (Saale)
| | - Kathrin Dietze
- Martin Luther University Halle-Wittenberg, Institute of Biology/Zoology, Department of Animal Physiology, Halle (Saale)
| | - Silvio Erler
- Institute for Bee Protection, Julius Kühn Institute (JKI)-Federal Research Centre for Cultivated Plants, Braunschweig, Germany
| | - Sina Cassau
- Martin Luther University Halle-Wittenberg, Institute of Biology/Zoology, Department of Animal Physiology, Halle (Saale)
| | - Jürgen Krieger
- Martin Luther University Halle-Wittenberg, Institute of Biology/Zoology, Department of Animal Physiology, Halle (Saale)
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28
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Sims C, Birkett MA, Withall DM. Enantiomeric Discrimination in Insects: The Role of OBPs and ORs. INSECTS 2022; 13:insects13040368. [PMID: 35447810 PMCID: PMC9030700 DOI: 10.3390/insects13040368] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/25/2022] [Accepted: 03/30/2022] [Indexed: 01/27/2023]
Abstract
Olfaction is a complex recognition process that is critical for chemical communication in insects. Though some insect species are capable of discrimination between compounds that are structurally similar, little is understood about how this high level of discrimination arises. Some insects rely on discriminating between enantiomers of a compound, demonstrating an ability for highly selective recognition. The role of two major peripheral olfactory proteins in insect olfaction, i.e., odorant-binding proteins (OBPs) and odorant receptors (ORs) has been extensively studied. OBPs and ORs have variable discrimination capabilities, with some found to display highly specialized binding capability, whilst others exhibit promiscuous binding activity. A deeper understanding of how odorant-protein interactions induce a response in an insect relies on further analysis such as structural studies. In this review, we explore the potential role of OBPs and ORs in highly specific recognition, specifically enantiomeric discrimination. We summarize the state of research into OBP and OR function and focus on reported examples in the literature of clear enantiomeric discrimination by these proteins.
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Affiliation(s)
- Cassie Sims
- Biointeractions and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK; (C.S.); (M.A.B.)
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Michael A. Birkett
- Biointeractions and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK; (C.S.); (M.A.B.)
| | - David M. Withall
- Biointeractions and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK; (C.S.); (M.A.B.)
- Correspondence: ; Tel.: +44-(0)-1582-938201
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Time-Dependent Odorant Sensitivity Modulation in Insects. INSECTS 2022; 13:insects13040354. [PMID: 35447796 PMCID: PMC9028461 DOI: 10.3390/insects13040354] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 01/18/2023]
Abstract
Simple Summary Insects, including blood-feeding female mosquitoes, can transmit deadly diseases, such as malaria, encephalitis, dengue, and yellow fever. Insects use olfaction to locate food sources, mates, and hosts. The nature of odorant plumes poses a challenge for insects in locating odorant sources in the environment. In order to modulate the system for the detection of fresh stimuli or changes in odorant concentrations, the olfaction system desensitizes to different concentrations and durations of stimuli. Without this ability, the chemotaxis behaviors of insects are defective. Thus, understanding how insects adjust their olfactory response dynamics to parse the chemical language of the external environment is not only a basic biology question but also has far-reaching implications for repellents and pest control. Abstract Insects use olfaction to detect ecologically relevant chemicals in their environment. To maintain useful responses over a variety of stimuli, olfactory receptor neurons are desensitized to prolonged or high concentrations of stimuli. Depending on the timescale, the desensitization is classified as short-term, which typically spans a few seconds; or long-term, which spans from minutes to hours. Compared with the well-studied mechanisms of desensitization in vertebrate olfactory neurons, the mechanisms underlying invertebrate olfactory sensitivity regulation remain poorly understood. Recently, using a large-scale functional screen, a conserved critical receptor phosphorylation site has been identified in the model insect Drosophila melanogaster, providing new insight into the molecular basis of desensitization in insects. Here, we summarize the progress in this area and provide perspectives on future directions to determine the molecular mechanisms that orchestrate the desensitization in insect olfaction.
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Odorant-receptor-mediated regulation of chemosensory gene expression in the malaria mosquito Anopheles gambiae. Cell Rep 2022; 38:110494. [PMID: 35263579 PMCID: PMC8957105 DOI: 10.1016/j.celrep.2022.110494] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/03/2022] [Accepted: 02/14/2022] [Indexed: 01/07/2023] Open
Abstract
Mosquitoes locate and approach humans based on the activity of odorant receptors (ORs) expressed on olfactory receptor neurons (ORNs). Olfactogenetic experiments in Anopheles gambiae mosquitoes revealed that the ectopic expression of an AgOR (AgOR2) in ORNs dampened the activity of the expressing neuron. This contrasts with studies in Drosophila melanogaster in which the ectopic expression of non-native ORs in ORNs confers ectopic neuronal responses without interfering with native olfactory physiology. RNA-seq analyses comparing wild-type antennae to those ectopically expressing AgOR2 in ORNs indicated that nearly all AgOR transcripts were significantly downregulated (except for AgOR2). Additional experiments suggest that AgOR2 protein rather than mRNA mediates this downregulation. Using in situ hybridization, we find that AgOR gene choice is active into adulthood and that AgOR2 expression inhibits AgORs from turning on at this late stage. Our study shows that the ORNs of Anopheles mosquitoes (in contrast to Drosophila) are sensitive to a currently unexplored mechanism of AgOR regulation. Maguire et al. discover that the ectopic expression of an olfactory receptor can downregulate the transcription of endogenous odorant receptors in mosquito olfactory neurons. The onset of mosquito odorant-receptor expression by an olfactory neuron continues into adult stages, and is particularly sensitive to exogenous olfactory reception expression.
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Gupta A, Singh SS, Mittal AM, Singh P, Goyal S, Kannan KR, Gupta AK, Gupta N. Mosquito Olfactory Response Ensemble enables pattern discovery by curating a behavioral and electrophysiological response database. iScience 2022; 25:103938. [PMID: 35265812 PMCID: PMC8899409 DOI: 10.1016/j.isci.2022.103938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 12/21/2021] [Accepted: 02/14/2022] [Indexed: 11/12/2022] Open
Abstract
Many experimental studies have examined behavioral and electrophysiological responses of mosquitoes to odors. However, the differences across studies in data collection, processing, and reporting make it difficult to perform large-scale analyses combining data from multiple studies. Here we extract and standardize data for 12 mosquito species, along with Drosophila melanogaster for comparison, from over 170 studies and curate the Mosquito Olfactory Response Ensemble (MORE), publicly available at https://neuralsystems.github.io/MORE. We demonstrate the ability of MORE in generating biological insights by finding patterns across studies. Our analyses reveal that ORs are tuned to specific ranges of several physicochemical properties of odorants; the empty-neuron recording technique for measuring OR responses is more sensitive than the Xenopus oocyte technique; there are systematic differences in the behavioral preferences reported by different types of assays; and odorants tend to become less attractive or more aversive at higher concentrations. MORE is a database of behavioral and electrophysiological responses to odors MORE includes data from 170 studies covering 12 species of mosquitoes along with flies MORE shows differences in odor preferences measured with different assays Empty-neuron technique measures responses more sensitively than the oocyte technique
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Miazzi F, Jain K, Kaltofen S, Bello JE, Hansson BS, Wicher D. Targeting Insect Olfaction in vivo and in vitro Using Functional Imaging. Front Cell Neurosci 2022; 16:839811. [PMID: 35281299 PMCID: PMC8907589 DOI: 10.3389/fncel.2022.839811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 02/03/2022] [Indexed: 11/13/2022] Open
Abstract
Insects decode volatile chemical signals from its surrounding environment with the help of its olfactory system, in a fast and reliable manner for its survival. In order to accomplish this task, odorant receptors (ORs) expressed in olfactory sensory neurons (OSNs) in the fly's antenna process such odor information. In order to study such a sophisticated process, we require access to the sensory neurons to perform functional imaging. In this article, we present different preparations to monitor odor information processing in Drosophila melanogaster OSNs using functional imaging of their Ca2+ dynamics. First, we established an in vivo preparation to image specific OSN population expressing the fluorescent Ca2+ reporter GCaMP3 during OR activation with airborne odors. Next, we developed a method to extract and to embed OSNs in a silica hydrogel with OR activation by dissolved odors. The odor response dynamics under these different conditions was qualitatively similar which indicates that the reduction of complexity did not affect the concentration dependence of odor responses at OSN level.
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Affiliation(s)
- Fabio Miazzi
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Kalpana Jain
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Sabine Kaltofen
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Jan E. Bello
- Department of Entomology, University of California, Riverside, Riverside, CA, United States
| | - Bill S. Hansson
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Dieter Wicher
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
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Koutroumpa F, Monsempès C, Anton S, François MC, Montagné N, Jacquin-Joly E. Pheromone Receptor Knock-Out Affects Pheromone Detection and Brain Structure in a Moth. Biomolecules 2022; 12:biom12030341. [PMID: 35327533 PMCID: PMC8945201 DOI: 10.3390/biom12030341] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/17/2022] [Accepted: 02/20/2022] [Indexed: 02/05/2023] Open
Abstract
Sex pheromone receptors are crucial in insects for mate finding and contribute to species premating isolation. Many pheromone receptors have been functionally characterized, especially in moths, but loss of function studies are rare. Notably, the potential role of pheromone receptors in the development of the macroglomeruli in the antennal lobe (the brain structures processing pheromone signals) is not known. Here, we used CRISPR-Cas9 to knock-out the receptor for the major component of the sex pheromone of the noctuid moth Spodoptera littoralis, and investigated the resulting effects on electrophysiological responses of peripheral pheromone-sensitive neurons and on the structure of the macroglomeruli. We show that the inactivation of the receptor specifically affected the responses of the corresponding antennal neurons did not impact the number of macroglomeruli in the antennal lobe but reduced the size of the macroglomerulus processing input from neurons tuned to the main pheromone component. We suggest that this mutant neuroanatomical phenotype results from a lack of neuronal activity due to the absence of the pheromone receptor and potentially reduced neural connectivity between peripheral and antennal lobe neurons. This is the first evidence of the role of a moth pheromone receptor in macroglomerulus development and extends our knowledge of the different functions odorant receptors can have in insect neurodevelopment.
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Affiliation(s)
- Fotini Koutroumpa
- Institute of Ecology and Environmental Sciences of Paris, INRAE, Sorbonne Université, CNRS, IRD, UPEC, Université de Paris, 78000 Versailles, France; (F.K.); (C.M.); (M.-C.F.); (N.M.)
- INRAE, Université de Tours, ISP, 37380 Nouzilly, France
| | - Christelle Monsempès
- Institute of Ecology and Environmental Sciences of Paris, INRAE, Sorbonne Université, CNRS, IRD, UPEC, Université de Paris, 78000 Versailles, France; (F.K.); (C.M.); (M.-C.F.); (N.M.)
| | - Sylvia Anton
- Institute for Genetics, Environment and Plant Protection, INRAE, Institut Agro, Université Rennes 1, 49045 Angers, France;
| | - Marie-Christine François
- Institute of Ecology and Environmental Sciences of Paris, INRAE, Sorbonne Université, CNRS, IRD, UPEC, Université de Paris, 78000 Versailles, France; (F.K.); (C.M.); (M.-C.F.); (N.M.)
| | - Nicolas Montagné
- Institute of Ecology and Environmental Sciences of Paris, INRAE, Sorbonne Université, CNRS, IRD, UPEC, Université de Paris, 78000 Versailles, France; (F.K.); (C.M.); (M.-C.F.); (N.M.)
| | - Emmanuelle Jacquin-Joly
- Institute of Ecology and Environmental Sciences of Paris, INRAE, Sorbonne Université, CNRS, IRD, UPEC, Université de Paris, 78000 Versailles, France; (F.K.); (C.M.); (M.-C.F.); (N.M.)
- Correspondence:
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Guo H, Huang LQ, Gong XL, Wang CZ. Comparison of functions of pheromone receptor repertoires in Helicoverpa armigera and Helicoverpa assulta using a Drosophila expression system. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2022; 141:103702. [PMID: 34942332 DOI: 10.1016/j.ibmb.2021.103702] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 12/07/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
Helicoverpa armigera and H. assulta are sympatric closely related species sharing two sex pheromone components, (Z)-11-hexadecenal (Z11-16:Ald) and (Z)-9-hexadecenal (Z9-16:Ald) but in opposite ratios, 97:3 and 3:97 respectively. This feature makes them a feasible model for studying the evolution of pheromone coding mechanisms of lepidopteran insects. Despite a decade-long study to deorphanize the pheromone receptor (PR) repertoires of the two species, the comparison of the function of all PR orthologs between the two species is incomplete. Moreover, the ligands of OR14 and OR15 have so far not been found, likely due to the missing of the active ligand(s) in the compound panel and/or incompatibility of heterologous expression systems used. In the present study, we expressed the PR repertoires of both Helicoverpa species in Drosophila T1 neurons to comparatively study the function of PRs. Among those PRs, OR13, OR6, and OR14 of both species are functionally conserved and narrowly tuned, and the T1 neurons expressing each of them respond to Z11-16:Ald, (Z)-9-hexadecenol (Z9-16:OH), and (Z)-11-hexadecenyl acetate (Z11-16:Ac), respectively. While HarmOR16-expressing neurons respond strongly to (Z)-9-tetradecenal (Z9-14:Ald) and (Z)-11-hexadecenol (Z11-16:OH), the neurons expressing HassOR16 mainly respond to Z9-14:Ald and also weakly respond to (Z)-9-tetradecenol (Z9-14:OH). Moreover, HarmOR14b-expressing neurons are activated by Z9-14:Ald, whereas HassOR14b-expressing neurons are sensitive to Z9-16:Ald, Z9-14:Ald, and (Z)-9-hexadecenol (Z9-16:OH). In addition, HarmOR15-expressing neurons are selectively responsive to Z9-14:Ald. However, the Drosophila T1 neurons expressing either HarmOR11 or HassOR11 are silent to all of the compounds tested. In summary, except for OR11, we have deorphanized all the PRs of these two Helicoverpa species using a Drosophila expression system and a large panel of pheromone compounds, thereby providing a valuable reference for parsing the code of peripheral coding of pheromones.
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Affiliation(s)
- Hao Guo
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Ling-Qiao Huang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Xin-Lin Gong
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Chen-Zhu Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, PR China.
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Drosophila melanogaster Chemosensory Pathways as Potential Targets to Curb the Insect Menace. INSECTS 2022; 13:insects13020142. [PMID: 35206716 PMCID: PMC8874460 DOI: 10.3390/insects13020142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/19/2022] [Accepted: 01/25/2022] [Indexed: 11/17/2022]
Abstract
Simple Summary The perception and processing of chemosensory stimuli are indispensable to the survival of living organisms. In insects, olfaction and gustation play a critical role in seeking food, finding mates and avoiding signs of danger. This review aims to present updated information about olfactory and gustatory signaling in the fruit fly Drosophila melanogaster. We have described the mechanisms involved in olfactory and gustatory perceptions at the molecular level, the receptors along with the allied molecules involved, and their signaling pathways in the fruit fly. Due to the magnifying problems of disease-causing insect vectors and crop pests, the applications of chemosensory signaling in controlling pests and insect vectors are also discussed. Abstract From a unicellular bacterium to a more complex human, smell and taste form an integral part of the basic sensory system. In fruit flies Drosophila melanogaster, the behavioral responses to odorants and tastants are simple, though quite sensitive, and robust. They explain the organization and elementary functioning of the chemosensory system. Molecular and functional analyses of the receptors and other critical molecules involved in olfaction and gustation are not yet completely understood. Hence, a better understanding of chemosensory cue-dependent fruit flies, playing a major role in deciphering the host-seeking behavior of pathogen transmitting insect vectors (mosquitoes, sandflies, ticks) and crop pests (Drosophila suzukii, Queensland fruit fly), is needed. Using D. melanogaster as a model organism, the knowledge gained may be implemented to design new means of controlling insects as well as in analyzing current batches of insect and pest repellents. In this review, the complete mechanisms of olfactory and gustatory perception, along with their implementation in controlling the global threat of disease-transmitting insect vectors and crop-damaging pests, are explained in fruit flies.
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Tumkaya T, Burhanudin S, Khalilnezhad A, Stewart J, Choi H, Claridge-Chang A. Most primary olfactory neurons have individually neutral effects on behavior. eLife 2022; 11:71238. [PMID: 35044905 PMCID: PMC8806191 DOI: 10.7554/elife.71238] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Accepted: 01/17/2022] [Indexed: 11/13/2022] Open
Abstract
Animals use olfactory receptors to navigate mates, food, and danger. However, for complex olfactory systems, it is unknown what proportion of primary olfactory sensory neurons can individually drive avoidance or attraction. Similarly, the rules that govern behavioral responses to receptor combinations are unclear. We used optogenetic analysis in Drosophila to map the behavior elicited by olfactory-receptor neuron (ORN) classes: just one-fifth of ORN-types drove either avoidance or attraction. Although wind and hunger are closely linked to olfaction, neither had much effect on single-class responses. Several pooling rules have been invoked to explain how ORN types combine their behavioral influences; we activated two-way combinations and compared patterns of single- and double-ORN responses: these comparisons were inconsistent with simple pooling. We infer that the majority of primary olfactory sensory neurons have neutral behavioral effects individually, but participate in broad, odor-elicited ensembles with potent behavioral effects arising from complex interactions.
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Affiliation(s)
| | | | | | - James Stewart
- Program in Neuroscience and Behavioral Disorders, Duke NUS Graduate Medical School
| | - Hyungwon Choi
- Department of Medicine, National University of Singapore
| | - Adam Claridge-Chang
- Program in Neuroscience and Behavioral Disorders, Duke NUS Graduate Medical School
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37
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Matsunaga T, Reisenman CE, Goldman-Huertas B, Brand P, Miao K, Suzuki HC, Verster KI, Ramírez SR, Whiteman NK. Evolution of olfactory receptors tuned to mustard oils in herbivorous Drosophilidae. Mol Biol Evol 2021; 39:6486429. [PMID: 34963012 PMCID: PMC8826531 DOI: 10.1093/molbev/msab362] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The diversity of herbivorous insects is attributed to their propensity to specialize on toxic plants. In an evolutionary twist, toxins betray the identity of their bearers when herbivores coopt them as cues for host-plant finding, but the evolutionary mechanisms underlying this phenomenon are poorly understood. We focused on Scaptomyza flava, an herbivorous drosophilid specialized on isothiocyanate (ITC)-producing (Brassicales) plants, and identified Or67b paralogs that were triplicated as mustard-specific herbivory evolved. Using in vivo heterologous systems for the expression of olfactory receptors, we found that S. flava Or67bs, but not the homologs from microbe-feeding relatives, responded selectively to ITCs, each paralog detecting different ITC subsets. Consistent with this, S. flava was attracted to ITCs, as was Drosophila melanogaster expressing S. flava Or67b3 in the homologous Or67b olfactory circuit. ITCs were likely coopted as olfactory attractants through gene duplication and functional specialization (neofunctionalization and subfunctionalization) in S. flava, a recently derived herbivore.
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Affiliation(s)
- Teruyuki Matsunaga
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA
| | - Carolina E Reisenman
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA.,Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA
| | - Benjamin Goldman-Huertas
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA.,Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ
| | - Philipp Brand
- Department of Evolution and Ecology, University of California Davis, Davis, CA
| | - Kevin Miao
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA
| | - Hiromu C Suzuki
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA
| | - Kirsten I Verster
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA
| | - Santiago R Ramírez
- Department of Evolution and Ecology, University of California Davis, Davis, CA
| | - Noah K Whiteman
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA.,Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA
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38
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Antennal lobe organisation in ant, Oecophylla smaragdina: A Golgi study. J Biosci 2021. [DOI: 10.1007/s12038-021-00233-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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39
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Vulpe A, Menuz K. Ir76b is a Co-receptor for Amine Responses in Drosophila Olfactory Neurons. Front Cell Neurosci 2021; 15:759238. [PMID: 34867202 PMCID: PMC8635857 DOI: 10.3389/fncel.2021.759238] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/27/2021] [Indexed: 11/22/2022] Open
Abstract
Two large families of olfactory receptors, the Odorant Receptors (ORs) and Ionotropic Receptors (IRs), mediate responses to most odors in the insect olfactory system. Individual odorant binding "tuning" OrX receptors are expressed by olfactory neurons in basiconic and trichoid sensilla and require the co-receptor Orco. The situation for IRs is more complex. Different tuning IrX receptors are expressed by olfactory neurons in coeloconic sensilla and rely on either the Ir25a or Ir8a co-receptors; some evidence suggests that Ir76b may also act as a co-receptor, but its function has not been systematically examined. Surprisingly, recent data indicate that nearly all coeloconic olfactory neurons co-express Ir25a, Ir8a, and Ir76b. Here, we demonstrate that Ir76b and Ir25a function together in all amine-sensing olfactory receptor neurons. In most neurons, loss of either co-receptor abolishes amine responses. In contrast, amine responses persist in the absence of Ir76b or Ir25a in ac1 sensilla but are lost in a double mutant. We show that responses mediated by acid-sensing neurons do not require Ir76b, despite their expression of this co-receptor. Our study also demonstrates that one population of coeloconic olfactory neurons exhibits Ir76b/Ir25a-dependent and Orco-dependent responses to distinct odorants. Together, our data establish the role of Ir76b as a bona fide co-receptor, which acts in partnership with Ir25a. Given that these co-receptors are among the most highly conserved olfactory receptors and are often co-expressed in chemosensory neurons, our data suggest Ir76b and Ir25a also work in tandem in other insects.
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Affiliation(s)
- Alina Vulpe
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
| | - Karen Menuz
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
- Connecticut Institute for Brain and Cognitive Sciences, University of Connecticut, Storrs, CT, United States
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40
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Llopis-Giménez A, Caballero-Vidal G, Jacquin-Joly E, Crava CM, Herrero S. Baculovirus infection affects caterpillar chemoperception. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2021; 138:103648. [PMID: 34536505 DOI: 10.1016/j.ibmb.2021.103648] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 09/11/2021] [Accepted: 09/11/2021] [Indexed: 06/13/2023]
Abstract
Baculoviruses are double-stranded DNA entomopathogenic viruses that infect predominantly insects of the order Lepidoptera. Research in the last decade has started to disentangle the mechanisms underlying the insect-virus interaction, particularly focusing on the effects of the baculovirus infection in the host's physiology. Among crucial physiological functions, olfaction has a key role in reproductive tasks, food source detection and enemy avoidance. In this work, we describe that Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) induces expression changes in some odorant receptors (ORs) - the centrepiece of insect's olfaction - when infecting larvae from its natural host Spodoptera exigua (Lepidoptera: Noctuidae). Different ORs are up-regulated in larvae after SeMNPV infection, and two of them, SexiOR35 and SexiOR23, were selected for further functional characterization by heterologous expression in empty neurons of Drosophila melanogaster coupled to single-sensillum recordings. SexiOR35 appears to be a broadly tuned receptor able to recognise multiple and different chemical compounds. SexiOR23, although correctly expressed in Drosophila neurons, did not display any significant response to a panel of 58 stimuli. Behavioural experiments revealed that larvae infected by SeMNPV exhibit altered olfactory-driven behaviour to diet when it is supplemented with the plant volatiles linalool or estragole, two of the main SexiOR35 ligands, supporting the hypothesis that viral infection triggers changes in host perception through changes in the expression level of specific ORs.
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Affiliation(s)
- Angel Llopis-Giménez
- Department of Genetics, University Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, 46100, Burjassot (València), Spain
| | - Gabriela Caballero-Vidal
- INRAE, Sorbonne Université, CNRS, IRD, UPEC, Université de Paris, Institute of Ecology and Environmental Sciences of Paris, F78026, Versailles Cedex, France
| | - Emmanuelle Jacquin-Joly
- INRAE, Sorbonne Université, CNRS, IRD, UPEC, Université de Paris, Institute of Ecology and Environmental Sciences of Paris, F78026, Versailles Cedex, France
| | - Cristina Maria Crava
- Department of Genetics, University Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, 46100, Burjassot (València), Spain.
| | - Salvador Herrero
- Department of Genetics, University Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, 46100, Burjassot (València), Spain.
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41
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Revadi SV, Giannuzzi VA, Rossi V, Hunger GM, Conchou L, Rondoni G, Conti E, Anderson P, Walker WB, Jacquin-Joly E, Koutroumpa F, Becher PG. Stage-specific expression of an odorant receptor underlies olfactory behavioral plasticity in Spodoptera littoralis larvae. BMC Biol 2021; 19:231. [PMID: 34706739 PMCID: PMC8555055 DOI: 10.1186/s12915-021-01159-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 09/27/2021] [Indexed: 11/21/2022] Open
Abstract
Background The detection of environmental cues and signals via the sensory system directs behavioral choices in diverse organisms. Insect larvae rely on input from the chemosensory system, mainly olfaction, for locating food sources. In several lepidopteran species, foraging behavior and food preferences change across larval instars; however, the molecular mechanisms underlying such behavioral plasticity during larval development are not fully understood. Here, we hypothesize that expression patterns of odorant receptors (ORs) change during development, as a possible mechanism influencing instar-specific olfactory-guided behavior and food preferences. Results We investigated the expression patterns of ORs in larvae of the cotton leafworm Spodoptera littoralis between the first and fourth instar and revealed that some of the ORs show instar-specific expression. We functionally characterized one OR expressed in the first instar, SlitOR40, as responding to the plant volatile, β-caryophyllene and its isomer α-humulene. In agreement with the proposed hypothesis, we showed that first but not fourth instar larvae responded behaviorally to β-caryophyllene and α-humulene. Moreover, knocking out this odorant receptor via CRISPR-Cas9, we confirmed that instar-specific responses towards its cognate ligands rely on the expression of SlitOR40. Conclusion Our results provide evidence that larvae of S. littoralis change their peripheral olfactory system during development. Furthermore, our data demonstrate an unprecedented instar-specific behavioral plasticity mediated by an OR, and knocking out this OR disrupts larval behavioral plasticity. The ecological relevance of such behavioral plasticity for S. littoralis remains to be elucidated, but our results demonstrate an olfactory mechanism underlying this plasticity in foraging behavior during larval development. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01159-1.
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Affiliation(s)
- Santosh V Revadi
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Box 190, 23422, Lomma, Sweden. .,INRAE, Sorbonne Université, CNRS, IRD, UPEC, Université Paris Diderot, Institute of Ecology and Environmental Sciences of Paris, Department of Sensory Ecology, Route de Saint-Cyr, 78026, Versailles Cedex, France.
| | - Vito Antonio Giannuzzi
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Box 190, 23422, Lomma, Sweden.,Department of Agricultural, Food and Environmental Sciences, University of Perugia, 06121, Perugia, Italy
| | - Valeria Rossi
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Box 190, 23422, Lomma, Sweden.,Department of Agricultural, Food and Environmental Sciences, University of Perugia, 06121, Perugia, Italy
| | - Gert Martin Hunger
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Box 190, 23422, Lomma, Sweden
| | - Lucie Conchou
- AGRIODOR, 6 rue Pierre Joseph Colin, 35000, Rennes, France
| | - Gabriele Rondoni
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, 06121, Perugia, Italy
| | - Eric Conti
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, 06121, Perugia, Italy
| | - Peter Anderson
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Box 190, 23422, Lomma, Sweden
| | - William B Walker
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Box 190, 23422, Lomma, Sweden.,United States Department of Agriculture - Agricultural Research Service, Temperate Tree Fruit and Vegetable Research Unit, 5230 Konnowac Pass Road, Wapato, WA, 98951, USA
| | - Emmanuelle Jacquin-Joly
- INRAE, Sorbonne Université, CNRS, IRD, UPEC, Université Paris Diderot, Institute of Ecology and Environmental Sciences of Paris, Department of Sensory Ecology, Route de Saint-Cyr, 78026, Versailles Cedex, France
| | - Fotini Koutroumpa
- INRAE, Sorbonne Université, CNRS, IRD, UPEC, Université Paris Diderot, Institute of Ecology and Environmental Sciences of Paris, Department of Sensory Ecology, Route de Saint-Cyr, 78026, Versailles Cedex, France
| | - Paul G Becher
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Box 190, 23422, Lomma, Sweden
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Zhu X, Xu B, Qin Z, Kader A, Song B, Chen H, Liu Y, Liu W. Identification of Candidate Olfactory Genes in Scolytus schevyrewi Based on Transcriptomic Analysis. Front Physiol 2021; 12:717698. [PMID: 34671270 PMCID: PMC8521011 DOI: 10.3389/fphys.2021.717698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 08/30/2021] [Indexed: 11/20/2022] Open
Abstract
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.
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Affiliation(s)
- Xiaofeng Zhu
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Oasis, Ministry of Agriculture and Rural Affairs, Institute of Plant Protection, Xinjiang Academy of Agricultural Sciences, Urumqi, China
| | - Bingqiang Xu
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Oasis, Ministry of Agriculture and Rural Affairs, Institute of Plant Protection, Xinjiang Academy of Agricultural Sciences, Urumqi, China
| | - Zhenjie Qin
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Abudukyoum Kader
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Oasis, Ministry of Agriculture and Rural Affairs, Institute of Plant Protection, Xinjiang Academy of Agricultural Sciences, Urumqi, China
| | - Bo Song
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Oasis, Ministry of Agriculture and Rural Affairs, Institute of Plant Protection, Xinjiang Academy of Agricultural Sciences, Urumqi, China
| | - Haoyu Chen
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Oasis, Ministry of Agriculture and Rural Affairs, Institute of Plant Protection, Xinjiang Academy of Agricultural Sciences, Urumqi, China
| | - Yang Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Wei Liu
- Guangdong Laboratory for Lingnan Modern Agriculture (Shenzhen Branch), Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
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43
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Baldwin SR, Mohapatra P, Nagalla M, Sindvani R, Amaya D, Dickson HA, Menuz K. Identification and characterization of CYPs induced in the Drosophila antenna by exposure to a plant odorant. Sci Rep 2021; 11:20530. [PMID: 34654888 PMCID: PMC8521596 DOI: 10.1038/s41598-021-99910-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/04/2021] [Indexed: 12/13/2022] Open
Abstract
Members of the cytochrome p450 (CYP) enzyme family are abundantly expressed in insect olfactory tissues, where they are thought to act as Odorant Degrading Enzymes (ODEs). However, their contribution to olfactory signaling in vivo is poorly understood. This is due in part to the challenge of identifying which of the dozens of antennal-expressed CYPs might inactivate a given odorant. Here, we tested a high-throughput deorphanization strategy in Drosophila to identify CYPs that are transcriptionally induced by exposure to odorants. We discovered three CYPs selectively upregulated by geranyl acetate using transcriptional profiling. Although these CYPs are broadly expressed in the antenna in non-neuronal cells, electrophysiological recordings from CYP mutants did not reveal any changes in olfactory neuron responses to this odorant. Neurons were desensitized by pre-exposing flies to the odorant, but this effect was similar in CYP mutants. Together, our data suggest that the induction of a CYP gene by an odorant does not necessarily indicate a role for that CYP in neuronal responses to that odorant. We go on to show that some CYPs have highly restricted expression patterns in the antenna, and suggest that such CYPs may be useful candidates for further studies on olfactory CYP function.
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Affiliation(s)
- Shane R Baldwin
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, 06269, USA
- MBF Bioscience, Williston, VT, 05495, USA
| | - Pratyajit Mohapatra
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, 06269, USA
| | - Monica Nagalla
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, 06269, USA
- Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Rhea Sindvani
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, 06269, USA
- School of Medicine, University of Connecticut, Farmington, CT, 06032, USA
| | - Desiree Amaya
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, 06269, USA
- Biomedical Sciences Program, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Hope A Dickson
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, 06269, USA
| | - Karen Menuz
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, 06269, USA.
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, 06269, USA.
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Mika K, Benton R. Olfactory Receptor Gene Regulation in Insects: Multiple Mechanisms for Singular Expression. Front Neurosci 2021; 15:738088. [PMID: 34602974 PMCID: PMC8481607 DOI: 10.3389/fnins.2021.738088] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 08/24/2021] [Indexed: 12/25/2022] Open
Abstract
The singular expression of insect olfactory receptors in specific populations of olfactory sensory neurons is fundamental to the encoding of odors in patterns of neuronal activity in the brain. How a receptor gene is selected, from among a large repertoire in the genome, to be expressed in a particular neuron is an outstanding question. Focusing on Drosophila melanogaster, where most investigations have been performed, but incorporating recent insights from other insect species, we review the multilevel regulatory mechanisms of olfactory receptor expression. We discuss how cis-regulatory elements, trans-acting factors, chromatin modifications, and feedback pathways collaborate to activate and maintain expression of the chosen receptor (and to suppress others), highlighting similarities and differences with the mechanisms underlying singular receptor expression in mammals. We also consider the plasticity of receptor regulation in response to environmental cues and internal state during the lifetime of an individual, as well as the evolution of novel expression patterns over longer timescales. Finally, we describe the mechanisms and potential significance of examples of receptor co-expression.
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Affiliation(s)
| | - Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
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45
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Roberts RE, Yuvaraj JK, Andersson MN. Codon Optimization of Insect Odorant Receptor Genes May Increase Their Stable Expression for Functional Characterization in HEK293 Cells. Front Cell Neurosci 2021; 15:744401. [PMID: 34552471 PMCID: PMC8450354 DOI: 10.3389/fncel.2021.744401] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 08/17/2021] [Indexed: 11/13/2022] Open
Abstract
Insect odorant receptor (OR) genes are routinely expressed in Human Embryonic Kidney (HEK) 293 cells for functional characterization ("de-orphanization") using transient or stable expression. However, progress in this research field has been hampered because some insect ORs are not functional in this system, which may be due to insufficient protein levels. We investigated whether codon optimization of insect OR sequences for expression in human cells could facilitate their functional characterization in HEK293 cells with stable and inducible expression. We tested the olfactory receptor co-receptor (Orco) proteins from the bark beetles Ips typographus ("Ityp") and Dendroctonus ponderosae ("Dpon"), and six ItypORs previously characterized in Xenopus laevis oocytes and/or HEK cells. Western blot analysis indicated that codon optimization yielded increased cellular protein levels for seven of the eight receptors. Our experimental assays demonstrated that codon optimization enabled functional characterization of two ORs (ItypOR25 and ItypOR29) which are unresponsive when expressed from wildtype (non-codon optimized) genes. Similar to previous Xenopus oocyte recordings, ItypOR25 responded primarily to the host/conifer monoterpene (+)-3-carene. ItypOR29 responded primarily to (+)-isopinochamphone and similar ketones produced by fungal symbionts and trees. Codon optimization also resulted in significantly increased responses in ItypOR49 to its pheromone ligand (R)-(-)-ipsdienol, and improved responses to the Orco agonist VUAA1 in ItypOrco. However, codon optimization did not result in functional expression of DponOrco, ItypOR23, ItypOR27, and ItypOR28 despite higher protein levels as indicated by Western blots. We conclude that codon optimization may enable or improve the functional characterization of insect ORs in HEK cells, although this method is not sufficient for all ORs that are not functionally expressed from wildtype genes.
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46
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Shaw KH, Dent CI, Johnson TK, Anderson A, de Bruyne M, Warr CG. Natural variation at the Drosophila melanogaster Or22 odorant receptor locus is associated with changes in olfactory behaviour. Open Biol 2021; 11:210158. [PMID: 34582710 PMCID: PMC8478520 DOI: 10.1098/rsob.210158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
In insects, many critical olfactory behaviours are mediated by the large odorant receptor (Or) gene family, which determines the response properties of different classes of olfactory receptor neurons (ORNs). While ORN responses are generally conserved within and between Drosophila species, variant alleles of the D. melanogaster Or22 locus have previously been shown to alter the response profile of an ORN class called ab3A. These alleles show potential clinal variation, suggesting that selection is acting at this locus. Here, we investigated if the changes seen in ab3A responses lead to changes in olfactory-related behaviours. We show that variation at the Or22 locus and in the ab3A neurons are not fully compensated for by other ORNs and lead to overall changes in antennal odorant detection. We further show that this correlates with differences in odorant preference behaviour and with differences in oviposition site preference, with flies that have the chimaeric short allele strongly preferring to oviposit on banana. These findings indicate that variation at the Or22 locus leads to changes in olfactory-driven behaviours, and add support to the idea that the ab3A neurons are of especial importance to the ecology of Drosophila flies.
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Affiliation(s)
- Katherine H. Shaw
- Tasmanian School of Medicine, University of Tasmania, Hobart 7000, Tasmania, Australia
| | - Craig I. Dent
- School of Biological Sciences, Monash University, Clayton 3800, Victoria, Australia
| | - Travis K. Johnson
- School of Biological Sciences, Monash University, Clayton 3800, Victoria, Australia
| | - Alisha Anderson
- Ecosystems Sciences, CSIRO, Black Mountain, Australian Capital Territory 2601, Australia
| | - Marien de Bruyne
- School of Biological Sciences, Monash University, Clayton 3800, Victoria, Australia
| | - Coral G. Warr
- Tasmanian School of Medicine, University of Tasmania, Hobart 7000, Tasmania, Australia,School of Biological Sciences, Monash University, Clayton 3800, Victoria, Australia,School of Molecular Sciences, La Trobe University, Bundoora 3083, Victoria, Australia
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47
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Caballero-Vidal G, Bouysset C, Gévar J, Mbouzid H, Nara C, Delaroche J, Golebiowski J, Montagné N, Fiorucci S, Jacquin-Joly E. Reverse chemical ecology in a moth: machine learning on odorant receptors identifies new behaviorally active agonists. Cell Mol Life Sci 2021; 78:6593-6603. [PMID: 34448011 PMCID: PMC8558168 DOI: 10.1007/s00018-021-03919-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 07/23/2021] [Accepted: 08/11/2021] [Indexed: 12/03/2022]
Abstract
The concept of reverse chemical ecology (exploitation of molecular knowledge for chemical ecology) has recently emerged in conservation biology and human health. Here, we extend this concept to crop protection. Targeting odorant receptors from a crop pest insect, the noctuid moth Spodoptera littoralis, we demonstrate that reverse chemical ecology has the potential to accelerate the discovery of novel crop pest insect attractants and repellents. Using machine learning, we first predicted novel natural ligands for two odorant receptors, SlitOR24 and 25. Then, electrophysiological validation proved in silico predictions to be highly sensitive, as 93% and 67% of predicted agonists triggered a response in Drosophila olfactory neurons expressing SlitOR24 and SlitOR25, respectively, despite a lack of specificity. Last, when tested in Y-maze behavioral assays, the most active novel ligands of the receptors were attractive to caterpillars. This work provides a template for rational design of new eco-friendly semiochemicals to manage crop pest populations.
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Affiliation(s)
- Gabriela Caballero-Vidal
- INRAE, Sorbonne Université, CNRS, IRD, UPEC, Université de Paris, Institute of Ecology and Environmental Sciences of Paris, 78000, Versailles, France.,Disease Vector Group, Chemical Ecology Unit, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden.,Max Planck Centre Next Generation Chemical Ecology, Uppsala, Sweden
| | - Cédric Bouysset
- Université Côte d'Azur, CNRS, Institut de Chimie de Nice UMR7272, 28 avenue Valrose, 06108, Nice, France
| | - Jérémy Gévar
- INRAE, Sorbonne Université, CNRS, IRD, UPEC, Université de Paris, Institute of Ecology and Environmental Sciences of Paris, 78000, Versailles, France
| | - Hayat Mbouzid
- INRAE, Sorbonne Université, CNRS, IRD, UPEC, Université de Paris, Institute of Ecology and Environmental Sciences of Paris, 78000, Versailles, France
| | - Céline Nara
- INRAE, Sorbonne Université, CNRS, IRD, UPEC, Université de Paris, Institute of Ecology and Environmental Sciences of Paris, 78000, Versailles, France
| | - Julie Delaroche
- INRAE, Sorbonne Université, CNRS, IRD, UPEC, Université de Paris, Institute of Ecology and Environmental Sciences of Paris, 78000, Versailles, France
| | - Jérôme Golebiowski
- Université Côte d'Azur, CNRS, Institut de Chimie de Nice UMR7272, 28 avenue Valrose, 06108, Nice, France.,Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, 711-873, South Korea
| | - Nicolas Montagné
- INRAE, Sorbonne Université, CNRS, IRD, UPEC, Université de Paris, Institute of Ecology and Environmental Sciences of Paris, 78000, Versailles, France.
| | - Sébastien Fiorucci
- Université Côte d'Azur, CNRS, Institut de Chimie de Nice UMR7272, 28 avenue Valrose, 06108, Nice, France.
| | - Emmanuelle Jacquin-Joly
- INRAE, Sorbonne Université, CNRS, IRD, UPEC, Université de Paris, Institute of Ecology and Environmental Sciences of Paris, 78000, Versailles, France.
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48
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Nava Gonzales C, McKaughan Q, Bushong EA, Cauwenberghs K, Ng R, Madany M, Ellisman MH, Su CY. Systematic morphological and morphometric analysis of identified olfactory receptor neurons in Drosophila melanogaster. eLife 2021; 10:69896. [PMID: 34423777 PMCID: PMC8410077 DOI: 10.7554/elife.69896] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 08/20/2021] [Indexed: 12/03/2022] Open
Abstract
The biophysical properties of sensory neurons are influenced by their morphometric and morphological features, whose precise measurements require high-quality volume electron microscopy (EM). However, systematic surveys of nanoscale characteristics for identified neurons are scarce. Here, we characterize the morphology of Drosophila olfactory receptor neurons (ORNs) across the majority of genetically identified sensory hairs. By analyzing serial block-face electron microscopy images of cryofixed antennal tissues, we compile an extensive morphometric data set based on 122 reconstructed 3D models for 33 of the 40 identified antennal ORN types. Additionally, we observe multiple novel features—including extracellular vacuoles within sensillum lumen, intricate dendritic branching, mitochondria enrichment in select ORNs, novel sensillum types, and empty sensilla containing no neurons—which raise new questions pertinent to cell biology and sensory neurobiology. Our systematic survey is critical for future investigations into how the size and shape of sensory neurons influence their responses, sensitivity, and circuit function.
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Affiliation(s)
- Cesar Nava Gonzales
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, San Diego, United States
| | - Quintyn McKaughan
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, San Diego, United States
| | - Eric A Bushong
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California, San Diego, San Diego, United States
| | - Kalyani Cauwenberghs
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, San Diego, United States
| | - Renny Ng
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, San Diego, United States
| | - Matthew Madany
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California, San Diego, San Diego, United States
| | - Mark H Ellisman
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California, San Diego, San Diego, United States
| | - Chih-Ying Su
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, San Diego, United States
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49
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Vulpe A, Kim HS, Ballou S, Wu ST, Grabe V, Nava Gonzales C, Liang T, Sachse S, Jeanne JM, Su CY, Menuz K. An ammonium transporter is a non-canonical olfactory receptor for ammonia. Curr Biol 2021; 31:3382-3390.e7. [PMID: 34111404 PMCID: PMC8355169 DOI: 10.1016/j.cub.2021.05.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/18/2021] [Accepted: 05/13/2021] [Indexed: 10/21/2022]
Abstract
Numerous hematophagous insects are attracted to ammonia, a volatile released in human sweat and breath.1-3 Low levels of ammonia also attract non-biting insects such as the genetic model organism Drosophila melanogaster and several species of agricultural pests.4,5 Two families of ligand-gated ion channels function as olfactory receptors in insects,6-10 and studies have linked ammonia sensitivity to a particular olfactory receptor in Drosophila.5,11,12 Given the widespread importance of ammonia to insect behavior, it is surprising that the genomes of most insects lack an ortholog of this gene.6 Here, we show that canonical olfactory receptors are not necessary for responses to ammonia in Drosophila. Instead, we demonstrate that a member of the ancient electrogenic ammonium transporter family, Amt, is likely a new type of olfactory receptor. We report two hitherto unidentified olfactory neuron populations that mediate neuronal and behavioral responses to ammonia in Drosophila. Their endogenous ammonia responses are lost in Amt mutant flies, and ectopic expression of either Drosophila or Anopheles Amt confers ammonia sensitivity. These results suggest that Amt is the first transporter known to function as an olfactory receptor in animals and that its function may be conserved across insect species.
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Affiliation(s)
- Alina Vulpe
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT 06269, USA
| | - Hyong S Kim
- Department of Neuroscience, Yale University, New Haven, CT 06510, USA
| | - Sydney Ballou
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT 06269, USA
| | - Shiuan-Tze Wu
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Veit Grabe
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena 07745, Germany
| | - Cesar Nava Gonzales
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Tiffany Liang
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT 06269, USA
| | - Silke Sachse
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena 07745, Germany
| | - James M Jeanne
- Department of Neuroscience, Yale University, New Haven, CT 06510, USA
| | - Chih-Ying Su
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Karen Menuz
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT 06269, USA; Connecticut Institute for Brain and Cognitive Sciences, University of Connecticut, Storrs, CT 06269, USA.
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50
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Jana SC, Dutta P, Jain A, Singh A, Adusumilli L, Girotra M, Kumari D, Shirolikar S, Ray K. Kinesin-2 transports Orco into the olfactory cilium of Drosophila melanogaster at specific developmental stages. PLoS Genet 2021; 17:e1009752. [PMID: 34411092 PMCID: PMC8407544 DOI: 10.1371/journal.pgen.1009752] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 08/31/2021] [Accepted: 07/29/2021] [Indexed: 12/21/2022] Open
Abstract
The cilium, the sensing centre for the cell, displays an extensive repertoire of receptors for various cell signalling processes. The dynamic nature of ciliary signalling indicates that the ciliary entry of receptors and associated proteins must be regulated and conditional. To understand this process, we studied the ciliary localisation of the odour-receptor coreceptor (Orco), a seven-pass transmembrane protein essential for insect olfaction. Little is known about when and how Orco gets into the cilia. Here, using Drosophila melanogaster, we show that the bulk of Orco selectively enters the cilia on adult olfactory sensory neurons in two discrete, one-hour intervals after eclosion. A conditional loss of heterotrimeric kinesin-2 during this period reduces the electrophysiological response to odours and affects olfactory behaviour. We further show that Orco binds to the C-terminal tail fragments of the heterotrimeric kinesin-2 motor, which is required to transfer Orco from the ciliary base to the outer segment and maintain within an approximately four-micron stretch at the distal portion of the ciliary outer-segment. The Orco transport was not affected by the loss of critical intraflagellar transport components, IFT172/Oseg2 and IFT88/NompB, respectively, during the adult stage. These results highlight a novel developmental regulation of seven-pass transmembrane receptor transport into the cilia and indicate that ciliary signalling is both developmentally and temporally regulated.
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Affiliation(s)
- Swadhin Chandra Jana
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
- Instituto Gulbenkian de Ciência (IGC), Oeiras, Portugal
| | - Priya Dutta
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Akanksha Jain
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Anjusha Singh
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Lavanya Adusumilli
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Mukul Girotra
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Diksha Kumari
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Seema Shirolikar
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Krishanu Ray
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
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