1
|
Li K, Yu S, Yang Y, He YZ, Wu Y. Mechanisms of feeding cessation in Helicoverpa armigera larvae exposed to Bacillus thuringiensis Cry1Ac toxin. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2023; 195:105565. [PMID: 37666620 DOI: 10.1016/j.pestbp.2023.105565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/27/2023] [Accepted: 08/01/2023] [Indexed: 09/06/2023]
Abstract
Insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) have been applied in sprayable formulations and expressed in transgenic crops for the control of pests in the field. When exposed to Bt proteins insect larvae display feeding cessation, yet the mechanism for this phenomenon remains unknown. In this study, we investigated the feeding behavior and underlying mechanisms of cotton bollworm (Helicoverpa armigera) larvae after exposure to the Cry1Ac protein from Bt. Three H. armigera strains were studied: the susceptible SCD strain, the C2/3-KO strain with HaABCC2 and HaABCC3 knocked out and high-level resistance to Cry1Ac (>15,000-fold), and the SCD-KI strain with a T92C point mutation in tetraspanin (HaTSPAN1) and medium-level resistance to Cry1Ac (125-fold). When determining the percentage of insects that continued feeding after various exposure times to Cry1Ac, we observed quick cessation of feeding in larvae from the susceptible SCD strain, whereas larvae from the C2/3-KO strain did not display feeding cessation. In contrast, larvae from the SCD-KI strain rapidly recovered from the initial feeding cessation. Histopathological analyses and qRT-PCR in midguts of SCD larvae after Cry1Ac exposure detected serious epithelial damage and significantly reduced expression of the neuropeptide F gene (NPF) and its potential receptor gene NPFR, which are reported to promote insect feeding. Neither epithelial damage nor altered NPF and NPFR expression appeared in midguts of C2/3-KO larvae after Cry1Ac treatment. The same treatment in SCD-KI larvae resulted in milder epithelial damage and subsequent repair, and a decrease followed by an initial increase in NPF and NPFR expression. These results demonstrate that the feeding cessation response to Cry1Ac in cotton bollworm larvae is closely associated with midgut epithelial damage and downregulation of NPF and NPFR expression. This information provides clues to the mechanism of feeding cessation in response to Bt intoxication and contributes to the mode of action of the Cry1Ac toxin in target pests.
Collapse
Affiliation(s)
- Kaixia Li
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Shan Yu
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Yihua Yang
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Ya-Zhou He
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Yidong Wu
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| |
Collapse
|
2
|
Roller L, Daubnerová I, Mizoguchi A, Satake H, Tanaka Y, Stano M, Klucar L, Žitňan D. Expression analysis of peptidergic enteroendocrine cells in the silkworm Bombyx mori. Cell Tissue Res 2022; 389:385-407. [PMID: 35829810 DOI: 10.1007/s00441-022-03666-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 06/27/2022] [Indexed: 11/25/2022]
Abstract
Enteroendocrine cells (ECs) in the insect midgut respond to physiological changes in the intestine by releasing multiple peptides to control food intake, gastrointestinal activity and systemic metabolism. Here, we performed a comprehensive mapping of ECs producing different regulatory peptides in the larval midgut of Bombyx mori. In total, we identified 20 peptide genes expressed in different ECs in specific regions of the midgut. Transcript-specific in situ hybridisation combined with antibody staining revealed approximately 30 subsets of ECs, each producing a unique peptide or a combination of several different peptides. Functional significance of this diversity and specific roles of different enteroendocrine peptides are largely unknown. Results of this study highlight the importance of the midgut as a major endocrine/paracrine source of regulatory molecules in insects and provide important information to clarify functions of ECs during larval feeding and development.
Collapse
Affiliation(s)
- Ladislav Roller
- Institute of Zoology, Slovak Academy of Sciences, Bratislava, Slovakia.
- Institute of Molecular Physiology and Genetics, Centre of Biosciences SAS, Bratislava, Slovakia.
| | - Ivana Daubnerová
- Institute of Zoology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Akira Mizoguchi
- Division of Liberal Arts and Sciences, Aichi Gakuin University, Nisshin, Aichi, Japan
| | - Honoo Satake
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Yoshiaki Tanaka
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Matej Stano
- Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Lubos Klucar
- Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Dušan Žitňan
- Institute of Zoology, Slovak Academy of Sciences, Bratislava, Slovakia
| |
Collapse
|
3
|
Mang D, Shu M, Endo H, Yoshizawa Y, Nagata S, Kikuta S, Sato R. Expression of a sugar clade gustatory receptor, BmGr6, in the oral sensory organs, midgut, and central nervous system of larvae of the silkworm Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2016; 70:85-98. [PMID: 26721200 DOI: 10.1016/j.ibmb.2015.12.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Revised: 11/22/2015] [Accepted: 12/20/2015] [Indexed: 06/05/2023]
Abstract
Insects taste nonvolatile chemicals through gustatory receptors (Grs) and make choices for feeding, mating, and oviposition. To date, genome projects have identified 69 Gr genes in the silkworm, Bombyx mori; however, the expression sites of these Grs remain to be explored. In this study, we used reverse transcription (RT)-PCR to investigate expression of the B. mori Gr-6 (BmGr6) gene, a member of the putative sugar clade gene family in various tissues. BmGr6 is expressed in the midgut, central nervous system (CNS), and oral sensory organs. Moreover, immunohistochemistry using an anti-BmGr6 antiserum demonstrated that BmGr6 is expressed in cells by oral sensory organs, midgut and nervous system. Furthermore, double-immunohistochemistry indicated that BmGr6 is expressed in midgut enteroendocrine cells, also in CNS neurosecretory cells. In particular, a portion of BmGr6-expressing cells, in both midgut and CNS, secretes FMRFamide-related peptides (FaRPs). These results suggest that BmGr6 functions not only as a taste receptor, but also as a chemical sensor such as for the regulation of gut movement, physiological conditions, and feeding behavior of larvae.
Collapse
Affiliation(s)
- Dingze Mang
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei 2-24-16, Tokyo 184-8588, Japan
| | - Min Shu
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei 2-24-16, Tokyo 184-8588, Japan
| | - Haruka Endo
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei 2-24-16, Tokyo 184-8588, Japan
| | - Yasutaka Yoshizawa
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei 2-24-16, Tokyo 184-8588, Japan
| | - Shinji Nagata
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Shingo Kikuta
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei 2-24-16, Tokyo 184-8588, Japan
| | - Ryoichi Sato
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei 2-24-16, Tokyo 184-8588, Japan.
| |
Collapse
|
4
|
Audsley N, Matthews HJ, Price NR, Weaver RJ. Allatoregulatory peptides in Lepidoptera, structures, distribution and functions. JOURNAL OF INSECT PHYSIOLOGY 2008; 54:969-980. [PMID: 18377924 DOI: 10.1016/j.jinsphys.2008.01.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2007] [Revised: 01/18/2008] [Accepted: 01/22/2008] [Indexed: 05/26/2023]
Abstract
Allatoregulatory peptides either inhibit (allatostatins) or stimulate (allatotropins) juvenile hormone (JH) synthesis by the corpora allata (CA) of insects. However, these peptides are pleitropic, the regulation of JH biosynthesis is not their only function. There are currently three allatostatin families (A-, B-, and C-type allatostatins) that inhibit JH biosynthesis, and two structurally unrelated allatotropins. The C-type allatostatin, characterised by its blocked N-terminus and a disulphide bridge between its two cysteine residues, was originally isolated from Manduca sexta. This peptide exists only in a single from in Lepidoptera and is the only peptide that has been shown to inhibit JH synthesis by the CA in vitro in this group of insects. The C-type allatostatin also inhibits spontaneous contractions of the foregut. The A-type allatostatins, which exist in multiple forms in a single insect, have also been characterised from Lepidoptera. This family of peptides does not appear to have any regulatory effect on JH biosynthesis, but does inhibit foregut muscle contractions. Two structurally unrelated allatotropins stimulate JH biosynthesis in Lepidoptera. The first was identified in M. sexta (Manse-AT) and occurs in other moths. The second (Spofr AT2) has only been identified in Spodoptera frugiperda. Manduca sexta allatotropin also stimulates heart muscle contractions and gut peristalsis, and inhibits ion transport across the midgut of larval M. sexta. The C-terminal (amide) pentapeptide of Manse-AT is important for JH biosynthesis activity. The most active conformation of Manse-AS requires the disulphide bridge, although the aromatic residues also have a significant effect on biological activity. Both A- and C-type allatostatins and Manse-AT are localised in neurosecretory cells of the brain and are present in the corpora cardiaca, CA and ventral nerve cord, although variations in localisation exist in different moths and at different stages of development. The presence of Manse-AS and Manse-AT in the CA correlates with the biological activity of these peptides on JH biosynthesis. There is currently no explanation for the presence of A-type allatostatins in the CA. The three peptide types are also co-localised in neurosecretory cells of the frontal ganglion, and are present in the recurrent nerve that supplies the muscles of the gut, particularly the crop and stomodeal valve, in agreement with their role in the regulation of gut peristalsis. There is also evidence that they are expressed in the midgut and reproductive tissues.
Collapse
Affiliation(s)
- N Audsley
- Central Science Laboratory, Sand Hutton, York YO41 1LZ, UK.
| | | | | | | |
Collapse
|
5
|
Christie AE, Sousa GL, Rus S, Smith CM, Towle DW, Hartline DK, Dickinson PS. Identification of A-type allatostatins possessing -YXFGI/Vamide carboxy-termini from the nervous system of the copepod crustacean Calanus finmarchicus. Gen Comp Endocrinol 2008; 155:526-33. [PMID: 17950732 DOI: 10.1016/j.ygcen.2007.09.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Revised: 08/23/2007] [Accepted: 09/12/2007] [Indexed: 11/24/2022]
Abstract
The copepod crustacean Calanus finmarchicus plays a critical role in the ecology of the Gulf of Maine and other regions of the North Atlantic. To increase our understanding of the physiology of this species, a normalized, whole organism cDNA library was constructed, and expressed sequence tags (ESTs) of the clones were generated. Among these ESTs was one with homology to known cDNAs encoding prepro-A-type allatostatins (A-type ASTs), a well-known family of arthropod peptides that regulate juvenile hormone production in insects. Sequence analysis of the clone from which the EST was generated, with subsequent translation of its open reading frame, showed it to encode five novel A-type ASTs, whose mature structures were predicted to be APYGFGIamide, pE/EPYGFGIamide, ALYGFGIamide, pE/EPYNFGIamide, and pQ/QPYNFGVamide. Each of the peptides is present as a single copy within the prepro-hormone with the exception of APYGFGIamide, which is present in three copies. Surprisingly, the organization of the Calanus prepro-A-type AST, specifically the number of encoded A-type peptides, is more similar to those of insects than it is to the known decapod crustacean prepro-hormones. Moreover, the Calanus A-type ASTs possess isoleucine or valine residues at their carboxy (C)-termini rather than leucine, which is present in most other family members. Wholemount immunohistochemistry suggests that six pairs of somata produce the native Calanus A-type ASTs: five in the protocerebrum and one in the suboesophageal region. To the best of our knowledge, our report is the first characterization of a neuropeptidergic system in a copepod, the first identification of A-type ASTs from a non-decapod crustacean, the first report of crustacean A-type ASTs possessing isoleucine C-terminal residues, and the first report from any species of an A-type peptide possessing a valine C-terminal residue.
Collapse
Affiliation(s)
- Andrew E Christie
- Department of Biology, University of Washington, Box 351800, Seattle, WA 98195-1800, USA.
| | | | | | | | | | | | | |
Collapse
|
6
|
Meyering-Vos M, Merz S, Sertkol M, Hoffmann KH. Functional analysis of the allatostatin-A type gene in the cricket Gryllus bimaculatus and the armyworm Spodoptera frugiperda. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2006; 36:492-504. [PMID: 16731345 DOI: 10.1016/j.ibmb.2006.03.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2005] [Revised: 03/22/2006] [Accepted: 03/23/2006] [Indexed: 05/09/2023]
Abstract
Double-stranded RNA (dsRNA) gene interference is an efficient method to silence gene expression in a sequence specific manner. Here we show, that dsRNA targeting the allatostatin (AS)-A type (FGL/I/V-amide) gene of Gryllus bimaculatus (Ensifera, Gryllidae) and Spodoptera frugiperda (Lepidoptera, Noctuidae) injected into freshly moulted larvae or adult crickets and moths produced a rapid and long-lasting reduction in the mRNA levels in various tissues. The effect lasted up to 7 days. Following dsRNA injection, the juvenile hormone (JH) titers in the hemolymph were clearly raised in both species. AS-dsRNA injection induced a reduced body weight in larval and adult crickets and the imaginal moult was incomplete. Silencing allatostatin type-A expression also reduced the egg and testes development in crickets, and the oviposition rate was drastically diminished in both species.
Collapse
Affiliation(s)
- Martina Meyering-Vos
- Department of Animal Ecology I, University of Bayreuth, Universitätsstr. 30, D-95440 Bayreuth, Germany.
| | | | | | | |
Collapse
|