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Wang Q, Smid HM, Dicke M, Haverkamp A. The olfactory system of Pieris brassicae caterpillars: from receptors to glomeruli. INSECT SCIENCE 2024; 31:469-488. [PMID: 38105530 DOI: 10.1111/1744-7917.13304] [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: 06/12/2023] [Revised: 10/17/2023] [Accepted: 10/30/2023] [Indexed: 12/19/2023]
Abstract
The olfactory system of adult lepidopterans is among the best described neuronal circuits. However, comparatively little is known about the organization of the olfactory system in the larval stage of these insects. Here, we explore the expression of olfactory receptors and the organization of olfactory sensory neurons in caterpillars of Pieris brassicae, a significant pest species in Europe and a well-studied species for its chemical ecology. To describe the larval olfactory system in this species, we first analyzed the head transcriptome of third-instar larvae (L3) and identified 16 odorant receptors (ORs) including the OR coreceptor (Orco), 13 ionotropic receptors (IRs), and 8 gustatory receptors (GRs). We then quantified the expression of these 16 ORs in different life stages, using qPCR, and found that the majority of ORs had significantly higher expression in the L4 stage than in the L3 and L5 stages, indicating that the larval olfactory system is not static throughout caterpillar development. Using an Orco-specific antibody, we identified all olfactory receptor neurons (ORNs) expressing the Orco protein in L3, L4, and L5 caterpillars and found a total of 34 Orco-positive ORNs, distributed among three sensilla on the antenna. The number of Orco-positive ORNs did not differ among the three larval instars. Finally, we used retrograde axon tracing of the antennal nerve and identified a mean of 15 glomeruli in the larval antennal center (LAC), suggesting that the caterpillar olfactory system follows a similar design as the adult olfactory system, although with a lower numerical redundancy. Taken together, our results provide a detailed analysis of the larval olfactory neurons in P. brassicae, highlighting both the differences as well as the commonalities with the adult olfactory system. These findings contribute to a better understanding of the development of the olfactory system in insects and its life-stage-specific adaptations.
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Affiliation(s)
- Qi Wang
- Laboratory of Entomology, Wageningen University and Research, Wageningen, the Netherlands
| | - Hans M Smid
- Laboratory of Entomology, Wageningen University and Research, Wageningen, the Netherlands
| | - Marcel Dicke
- Laboratory of Entomology, Wageningen University and Research, Wageningen, the Netherlands
| | - Alexander Haverkamp
- Laboratory of Entomology, Wageningen University and Research, Wageningen, the Netherlands
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Zou Y, Chen Y, Wang D, Xie X, Li G, Zheng C, Wen J, Su H, Liu X, Zeng L, Lu Y, Cao F. The Effects of Nine Compounds on Aldehyde-Oxidase-Related Genes in Bactrocera dorsalis (Hendel). Genes (Basel) 2023; 15:35. [PMID: 38254925 PMCID: PMC10815873 DOI: 10.3390/genes15010035] [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: 10/30/2023] [Revised: 12/15/2023] [Accepted: 12/17/2023] [Indexed: 01/24/2024] Open
Abstract
Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) (B. dorsalis) is an important agricultural, major invasive, and quarantine pest that can cause significant damage to the economic value of the fruit and vegetable industry. Male bait is one of the most effective methods of surveying, monitoring, and controlling B. dorsalis. In our study, we constructed cDNA libraries using total RNA extracted independently from the antennae, mouthparts, and thoracic legs of male and female adults and the ovipositors of female adults and screened out four aldehyde-oxidase-related genes (AOX-related), C58800, C66700, C67485, and C67698. Molecular docking predictions showed that eight compounds, including 3,4-dimethoxycinnamyl alcohol, 3,4-dimethoxy-cinnamaldehyde, deet, ethyl N-acetyl-N-butyl-β-alaninate, n-butyl butyrate, n-butyl butyrate, ethyl butyrate, methyl eugenol, and ethyl acetate, could combine with proteins encoded by the four B. dorsalis AOX-related genes. Furthermore, QPCR was performed to confirm that four compounds, including 3,4-dimethoxy cinnamic aldehyde, butyl levulinic acid ethyl ester (mosquito repellent), butyl butyrate, and methyl eugenol, induced significant changes in the AOX-related genes of B. dorsalis. These results provide useful information and guidance for the batch screening of potentially useful compounds and the search for effective attractants of B. dorsalis.
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Affiliation(s)
- Yan Zou
- School of Tropical Agriculture and Forestry, Hainan University, Haikou 570100, China; (Y.Z.); (X.X.); (J.W.); (X.L.)
| | - Yupeng Chen
- Department of Entomology, South China Agricultural University, Guangzhou 510642, China; (Y.C.); (G.L.); (C.Z.); (H.S.); (L.Z.); (Y.L.)
| | - Duoduo Wang
- College of Life Sciences, Zhejiang Normal University, Jinhua 321004, China;
| | - Xiaowei Xie
- School of Tropical Agriculture and Forestry, Hainan University, Haikou 570100, China; (Y.Z.); (X.X.); (J.W.); (X.L.)
| | - Gen Li
- Department of Entomology, South China Agricultural University, Guangzhou 510642, China; (Y.C.); (G.L.); (C.Z.); (H.S.); (L.Z.); (Y.L.)
| | - Chunyan Zheng
- Department of Entomology, South China Agricultural University, Guangzhou 510642, China; (Y.C.); (G.L.); (C.Z.); (H.S.); (L.Z.); (Y.L.)
| | - Jian Wen
- School of Tropical Agriculture and Forestry, Hainan University, Haikou 570100, China; (Y.Z.); (X.X.); (J.W.); (X.L.)
| | - Hongai Su
- Department of Entomology, South China Agricultural University, Guangzhou 510642, China; (Y.C.); (G.L.); (C.Z.); (H.S.); (L.Z.); (Y.L.)
| | - Xin Liu
- School of Tropical Agriculture and Forestry, Hainan University, Haikou 570100, China; (Y.Z.); (X.X.); (J.W.); (X.L.)
| | - Ling Zeng
- Department of Entomology, South China Agricultural University, Guangzhou 510642, China; (Y.C.); (G.L.); (C.Z.); (H.S.); (L.Z.); (Y.L.)
| | - Yongyue Lu
- Department of Entomology, South China Agricultural University, Guangzhou 510642, China; (Y.C.); (G.L.); (C.Z.); (H.S.); (L.Z.); (Y.L.)
| | - Fengqin Cao
- School of Tropical Agriculture and Forestry, Hainan University, Haikou 570100, China; (Y.Z.); (X.X.); (J.W.); (X.L.)
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Trebels B, Dippel S, Anders J, Ernst C, Goetz B, Keyser T, Rexer KH, Wimmer EA, Schachtner J. Anatomic and neurochemical analysis of the palpal olfactory system in the red flour beetle Tribolium castaneum, HERBST. Front Cell Neurosci 2023; 17:1097462. [PMID: 36998268 PMCID: PMC10043995 DOI: 10.3389/fncel.2023.1097462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 01/30/2023] [Indexed: 02/25/2023] Open
Abstract
The paired antennal lobes were long considered the sole primary processing centers of the olfactory pathway in holometabolous insects receiving input from the olfactory sensory neurons of the antennae and mouthparts. In hemimetabolous insects, however, olfactory cues of the antennae and palps are processed separately. For the holometabolous red flour beetle Tribolium castaneum, we could show that primary processing of the palpal and antennal olfactory input also occurs separately and at distinct neuronal centers. While the antennal olfactory sensory neurons project into the antennal lobes, those of the palps project into the paired glomerular lobes and the unpaired gnathal olfactory center. Here we provide an extended analysis of the palpal olfactory pathway by combining scanning electron micrographs with confocal imaging of immunohistochemical staining and reporter expression identifying chemosensory and odorant receptor-expressing neurons in the palpal sensilla. In addition, we extended the anatomical characterization of the gnathal olfactory center by 3D reconstructions and investigated the distribution of several neuromediators. The similarities in the neuromediator repertoire between antennal lobes, glomerular lobes, and gnathal olfactory center underline the role of the latter two as additional primary olfactory processing centers.
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Affiliation(s)
- Björn Trebels
- Animal Physiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
- *Correspondence: Joachim Schachtner Björn Trebels Ernst A. Wimmer
| | - Stefan Dippel
- Animal Physiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Janet Anders
- Animal Physiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Clara Ernst
- Animal Physiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Brigitte Goetz
- Animal Physiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Tim Keyser
- Animal Physiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Karl Heinz Rexer
- Biodiversity of Plants, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Ernst A. Wimmer
- Department of Developmental Biology, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, Georg-August-University Göttingen, Göttingen, Germany
- *Correspondence: Joachim Schachtner Björn Trebels Ernst A. Wimmer
| | - Joachim Schachtner
- Animal Physiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
- Clausthal University of Technology, Clausthal-Zellerfeld, Germany
- *Correspondence: Joachim Schachtner Björn Trebels Ernst A. Wimmer
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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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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; 12:341. [PMID: 35327533 PMCID: PMC8945201 DOI: 10.3390/biom12030341] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [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.)
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