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Xu D, Tong Y, Chen B, Li B, Wang S, Zhang D. The influence of first desaturase subfamily genes on fatty acid synthesis, desiccation tolerance and inter-caste nutrient transfer in the termite Coptotermes formosanus. INSECT MOLECULAR BIOLOGY 2024; 33:55-68. [PMID: 37750189 DOI: 10.1111/imb.12877] [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: 08/14/2022] [Accepted: 09/13/2023] [Indexed: 09/27/2023]
Abstract
Desaturase enzymes play an essential role in the biosynthesis of unsaturated fatty acids (UFAs). In this study, we identified seven "first desaturase" subfamily genes (Cfor-desatA1, Cfor-desatA2-a, Cfor-desatA2-b, Cfor-desatB-a, Cfor-desatB-b, Cfor-desatD and Cfor-desatE) from the Formosan subterranean termite Coptotermes formosanus. These desaturases were highly expressed in the cuticle and fat body of C. formosanus. Inhibition of either the Cfor-desatA2-a or Cfor-desatA2-b gene resulted in a significant decrease in the contents of fatty acids (C16:0, C18:0, C18:1 and C18:2) in worker castes. Moreover, we observed that inhibition of most of desaturase genes identified in this study had a negative impact on the survival rate and desiccation tolerance of workers. Interestingly, when normal soldiers were reared together with dsCfor-desatA2-b-treated workers, they exhibited higher mortality, suggesting that desaturase had an impact on trophallaxis among C. formosanus castes. Our findings shed light on the novel roles of desaturase family genes in the eusocial termite C. formosanus.
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Affiliation(s)
- Danni Xu
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou, China
| | - Yuxin Tong
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou, China
- School of Forestry and Biotechnology, Zhejiang A&F 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
| | - Baoling Li
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou, China
| | - Shengyin Wang
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou, China
| | - Dayu Zhang
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou, China
- School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, China
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Zhu Q, Li F, Shu Q, Feng P, Wang Y, Dai M, Mao T, Sun H, Wei J, Li B. Disruption of peritrophic matrix chitin metabolism and gut immune by chlorantraniliprole results in pathogenic bacterial infection in Bombyx mori. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2023; 193:105430. [PMID: 37248008 DOI: 10.1016/j.pestbp.2023.105430] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 04/13/2023] [Accepted: 04/18/2023] [Indexed: 05/31/2023]
Abstract
Chlorantraniliprole (CAP) is widely used in pest control, and its environmental residues affect the disease resistance of non-target insect silkworms. Studies have demonstrated that changes in gut microbial communities of insects are associated with susceptibility to pathogens. In the present study, we examined the effects of CAP exposure on the immune system and gut microbial community structure of silkworms. The results showed that after 96 h of exposure to low-concentration CAP, the peritrophic matrix (PM) of silkworm larvae was disrupted, and pathogenic bacteria invaded hemolymph. The trehalase activity in the midgut was significantly decreased, while the activities of chitinase, β-N-acetylglucosaminidase, and chitin deacetylase were increased considerably, resulting in decreased chitin content in PM. In addition, exposure to CAP reduced the expressions of key genes in the Toll, IMD, and JAK/STAT pathways, ultimately leading to the downregulation of antimicrobial peptides (AMPs) genes and alterations in the structure of the gut microbial community. Therefore, after infection with the conditional pathogen Enterobacter cloacae (E. cloacae), CAP-exposed individuals exhibited significantly lower body weight and higher mortality. These findings showed that exposure to low-concentration CAP impacted the biological defense system of silkworms, changed the gut microbial community structure, and increased silkworms' susceptibility to bacterial diseases. Collectively, these findings provided a new perspective for the safety evaluation of low-concentration CAP exposure in sericulture.
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Affiliation(s)
- Qingyu Zhu
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, PR China
| | - Fanchi Li
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, PR China; Sericulture Institute of Soochow University, Suzhou, Jiangsu 215123, PR China
| | - Qilong Shu
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, PR China
| | - Piao Feng
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, PR China
| | - Yuanfei Wang
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, PR China
| | - Minli Dai
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, PR China
| | - Tingting Mao
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, PR China
| | - Haina Sun
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, PR China; Sericulture Institute of Soochow University, Suzhou, Jiangsu 215123, PR China
| | - Jing Wei
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, PR China; Sericulture Institute of Soochow University, Suzhou, Jiangsu 215123, PR China
| | - Bing Li
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, PR China; Sericulture Institute of Soochow University, Suzhou, Jiangsu 215123, PR China.
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Peritrophin-like Genes Are Associated with Delousing Drug Response and Sensitivity in the Sea Louse Caligus rogercresseyi. Int J Mol Sci 2022; 23:ijms232113341. [DOI: 10.3390/ijms232113341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 10/28/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022] Open
Abstract
Caligus rogercresseyi is the main ectoparasite that affects the salmon industry in Chile. The mechanisms used by the parasite to support its life strategy are of great interest for developing control strategies. Due to the critical role of insect peritrophins in host–parasite interactions and response to pest control drugs, this study aimed to identify and characterize the peritrophin-like genes present in C. rogercresseyi. Moreover, the expression of peritrophin-like genes was evaluated on parasites exposed to delousing drugs such as pyrethroids and azamethiphos. Peritrophin genes were identified by homology analysis among the sea louse transcriptome database and arthropods peritrophin-protein database obtained from GenBank and UniProt. Moreover, the gene loci in the parasite genome were located. Furthermore, peritrophin gene expression levels were evaluated by RNA-Seq analysis in sea louse developmental stages and sea lice exposed to delousing drugs deltamethrin, cypermethrin, and azamethiphos. Seven putative peritrophin-like genes were identified in C. rogercresseyi with high homology with other crustacean peritrophins. Differences in the presence of signal peptides, the number of chitin-binding domains, and the position of conserved cysteines were found. In addition, seven peritrophin-like gene sequences were identified in the C. rogercresseyi genome. Gene expression analysis revealed a stage-dependent expression profile. Notably, differential regulation of peritrophin genes in resistant and susceptible populations to delousing drugs was found. These data are the first report and characterization of peritrophin genes in the sea louse C. rogercresseyi, representing valuable knowledge to understand sea louse biology. Moreover, this study provides evidence for a deeper understanding of the molecular basis of C. rogercresseyi response to delousing drugs.
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Ettinger CL, Byrne FJ, de Souza Pacheco I, Brown DJ, Walling LL, Atkinson PW, Redak RA, Stajich JE. Transcriptome and population structure of glassy-winged sharpshooters (Homalodisca vitripennis) with varying insecticide resistance in southern California. BMC Genomics 2022; 23:721. [PMID: 36273137 PMCID: PMC9587601 DOI: 10.1186/s12864-022-08939-1] [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: 08/15/2022] [Accepted: 10/13/2022] [Indexed: 12/02/2022] Open
Abstract
Background Homalodisca vitripennis Germar, the glassy-winged sharpshooter, is an invasive insect in California and a critical threat to agriculture through its transmission of the plant pathogen, Xylella fastidiosa. Quarantine, broad-spectrum insecticides, and biological control have been used for population management of H. vitripennis since its invasion and subsequent proliferation throughout California. Recently wide-spread neonicotinoid resistance has been detected in populations of H. vitripennis in the southern portions of California’s Central Valley. In order to better understand potential mechanisms of H. vitripennis neonicotinoid resistance, we performed RNA sequencing on wild-caught insecticide-resistant and relatively susceptible sharpshooters to profile their transcriptome and population structure. Results We identified 81 differentially expressed genes with higher expression in resistant individuals. The significant largest differentially expressed candidate gene linked to resistance status was a cytochrome P450 gene with similarity to CYP6A9. Furthermore, we observed an over-enrichment of GO terms representing functions supportive of roles in resistance mechanisms (cytochrome P450s, M13 peptidases, and cuticle structural proteins). Finally, we saw no evidence of broad-scale population structure, perhaps due to H. vitripennis' relatively recent introduction to California or due to the relatively small geographic scale investigated here. Conclusions In this work, we characterized the transcriptome of insecticide-resistant and susceptible H. vitripennis and identified candidate genes that may be involved in resistance mechanisms for this species. Future work should seek to build on the transcriptome profiling performed here to confirm the role of the identified genes, particularly the cytochrome P450, in resistance in H. vitripennis. We hope this work helps aid future population management strategies for this and other species with growing insecticide resistance. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08939-1.
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Affiliation(s)
- Cassandra L Ettinger
- Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA, USA.
| | - Frank J Byrne
- Department of Entomology, University of California, Riverside, Riverside, CA, USA
| | | | - Dylan J Brown
- Department of Entomology, University of California, Riverside, Riverside, CA, USA
| | - Linda L Walling
- Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, USA.,Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, USA
| | - Peter W Atkinson
- Department of Entomology, University of California, Riverside, Riverside, CA, USA.,Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, USA
| | - Richard A Redak
- Department of Entomology, University of California, Riverside, Riverside, CA, USA
| | - Jason E Stajich
- Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA, USA. .,Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, USA.
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Characteristics of the Peritrophic Matrix of the Silkworm, Bombyx mori and Factors Influencing Its Formation. INSECTS 2021; 12:insects12060516. [PMID: 34199436 PMCID: PMC8227122 DOI: 10.3390/insects12060516] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/25/2021] [Accepted: 05/28/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary The insect midgut is an important digestive organ with the peritrophic matrix (PM) being a semi-permeable membrane secreted by the midgut cells. The PM plays an important role in improving midgut digestion efficiency and protecting the midgut from food particles and exogenous pathogens. The silkworm, Bombyx mori, is an economically important insect. Understanding the structure of the PM is necessary for studying its function, but characteristics of PM in B. mori have been rarely reported. In this study, we conducted a comprehensive study on the PM structure of the PM in silkworms and found its thickness increased gradually during growth, but there was no difference in the thickness comparing the anterior, middle, and posterior regions. Permeability of the PM gradually decreased from the anterior to posterior regions. In addition, we found the formation of the PM was influenced by food ingestion and the gut microbiota. Abstract The peritrophic matrix (PM) secreted by the midgut cells of insects is formed by the binding of PM proteins to chitin fibrils. The PM envelops the food bolus, serving as a barrier between the content of the midgut lumen and its epithelium, and plays a protective role for epithelial cells against mechanical damage, pathogens, toxins, and other harmful substances. However, few studies have investigated the characteristics and synthesis factors of the PM in the silkworm, Bombyx mori. Here, we examined the characteristics of the PM in the silkworms. The PM thickness of the silkworms increased gradually during growth, while there was no significant difference in thickness along the entire PM region. Permeability of the PM decreased gradually from the anterior to posterior PM. We also found that PM synthesis was affected by food ingestion and the gut microbiota. Our results are beneficial for future studies regarding the function of the PM in silkworms.
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Bastarache P, Wajnberg G, Dumas P, Chacko S, Lacroix J, Crapoulet N, Moffat CE, Morin P. Transcriptomics-Based Approach Identifies Spinosad-Associated Targets in the Colorado Potato Beetle, Leptinotarsa decemlineata. INSECTS 2020; 11:insects11110820. [PMID: 33233355 PMCID: PMC7700309 DOI: 10.3390/insects11110820] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/18/2020] [Accepted: 11/19/2020] [Indexed: 12/13/2022]
Abstract
Simple Summary The Colorado potato beetle Leptinotarsa decemlineata is a potato pest that can cause substantial damages to potato crops worldwide. Multiple approaches have been leveraged to control this pest including the use of a variety of insecticides. Resistance to different insecticides aimed at controlling this insect has been reported and much work has been conducted in recent years to elucidate the underlying molecular changes associated with insecticide resistance in L. decemlineata. However, information is sparse regarding the molecular impact associated with spinosad treatment in this insect pest. The current study thus explores transcriptional changes associated with spinosad response in L. decemlineata exposed to this compound using high-throughput sequencing. Results presented show multiple transcripts of interest that exhibit differential expression in spinosad-treated L. decemlineata and provide a preliminary footprint of transcripts affected by this insecticide in this potato pest. Select targets identified in this signature should be further explored in follow-up studies to better characterize their contribution, if any, in the process of spinosad resistance. Abstract The Colorado potato beetle Leptinotarsa decemlineata is an insect pest that threatens potato crops globally. The primary method to control its damage on potato plants is the use of insecticides, including imidacloprid, chlorantraniliprole and spinosad. However, insecticide resistance has been frequently observed in Colorado potato beetles. The molecular targets and the basis of resistance to imidacloprid and chlorantraniliprole have both been previously quantified. This work was undertaken with the overarching goal of better characterizing the molecular changes associated with spinosad exposure in this insect pest. Next-generation sequencing was conducted to identify transcripts that were differentially expressed between Colorado potato beetles exposed to spinosad versus control insects. Results showed several transcripts that exhibit different expression levels between the two conditions, including ones coding for venom carboxylesterase-6, chitinase 10, juvenile hormone esterase and multidrug resistance-associated protein 4. In addition, several microRNAs, such as miR-12-3p and miR-750-3p, were also modulated in the investigated conditions. Overall, this work reveals a molecular footprint underlying spinosad response in Colorado potato beetles and provides novel leads that could be targeted as part of RNAi-based approaches to control this insect pest.
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Affiliation(s)
- Pierre Bastarache
- Department of Chemistry and Biochemistry, Université de Moncton, 18 Antonine-Maillet Avenue, Moncton, NB E1A 3E9, Canada; (P.B.); (P.D.)
| | - Gabriel Wajnberg
- Atlantic Cancer Research Institute, Pavillon Hôtel-Dieu 35 Providence Street, Moncton, NB E1C 8X3, Canada; (G.W.); (S.C.); (J.L.); (N.C.)
| | - Pascal Dumas
- Department of Chemistry and Biochemistry, Université de Moncton, 18 Antonine-Maillet Avenue, Moncton, NB E1A 3E9, Canada; (P.B.); (P.D.)
| | - Simi Chacko
- Atlantic Cancer Research Institute, Pavillon Hôtel-Dieu 35 Providence Street, Moncton, NB E1C 8X3, Canada; (G.W.); (S.C.); (J.L.); (N.C.)
| | - Jacynthe Lacroix
- Atlantic Cancer Research Institute, Pavillon Hôtel-Dieu 35 Providence Street, Moncton, NB E1C 8X3, Canada; (G.W.); (S.C.); (J.L.); (N.C.)
| | - Nicolas Crapoulet
- Atlantic Cancer Research Institute, Pavillon Hôtel-Dieu 35 Providence Street, Moncton, NB E1C 8X3, Canada; (G.W.); (S.C.); (J.L.); (N.C.)
| | - Chandra E. Moffat
- Fredericton Research and Development Centre, Agriculture and Agri-Food Canada, 850 Lincoln Road, Fredericton, NB E3B 4Z7, Canada;
| | - Pier Morin
- Department of Chemistry and Biochemistry, Université de Moncton, 18 Antonine-Maillet Avenue, Moncton, NB E1A 3E9, Canada; (P.B.); (P.D.)
- Correspondence: ; Tel.: +1-(506)-858-4355; Fax: +1-(506)-858-4541
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Zha XL, Yu XB, Zhang HY, Wang H, Huang XZ, Shen YH, Lu C. Identification of Peritrophins and Antiviral Effect of Bm01504 against BmNPV in the Silkworm, Bombyx mori. Int J Mol Sci 2020; 21:ijms21217973. [PMID: 33121000 PMCID: PMC7663561 DOI: 10.3390/ijms21217973] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 10/23/2020] [Accepted: 10/23/2020] [Indexed: 01/15/2023] Open
Abstract
The insect midgut secretes a semi-permeable, acellular peritrophic membrane (PM) that maintains intestinal structure, promotes digestion, and protects the midgut from food particles and pathogenic microorganisms. Peritrophin is an important PM protein (PMP) in the PM. Here, we identified 11 peritrophins with 1–16 chitin binding domains (CBDs) comprising 50–56 amino acid residues. Multiple CBDs in the same peritrophin clustered together, rather than by species. The CBD contained six highly conserved cysteine residues, with the key feature of amino acids between them being CX11-15CX5CX9-14CX11-12CX6-7C. Peritrophins with 2 and 4 CBDs (Bm09641 and Bm01504, respectively), and with 1, 8, and 16 CBDs (Bm11851, Bm00185, and Bm01491, respectively) were mainly expressed in the anterior midgut, and throughout the midgut, respectively. Survival rates of transgenic silkworms with Bm01504 overexpression (Bm01504-OE) and knockout (Bm01504-KO) infected with B. morinucleopolyhedrovirus (BmNPV) were significantly higher and lower, whereas expression of the key viral gene, p10, were lower and higher, respectively, compared with wild type (WT). Therefore, Bm01504-OE and Bm01504-KO transgenic silkworms were more and less resistant, respectively, to BmNPV. Bm01504 plays important roles in resisting BmNPV invasion. We provide a new perspective for studying PM function, and reveal how the silkworm midgut resists invasive exogenous pathogenic microorganisms.
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Affiliation(s)
- Xu-Le Zha
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Beibei, Chongqing 400715, China; (X.-L.Z.); (X.-B.Y.); (H.-Y.Z.); (H.W.)
| | - Xin-Bo Yu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Beibei, Chongqing 400715, China; (X.-L.Z.); (X.-B.Y.); (H.-Y.Z.); (H.W.)
| | - Hong-Yan Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Beibei, Chongqing 400715, China; (X.-L.Z.); (X.-B.Y.); (H.-Y.Z.); (H.W.)
| | - Han Wang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Beibei, Chongqing 400715, China; (X.-L.Z.); (X.-B.Y.); (H.-Y.Z.); (H.W.)
| | - Xian-Zhi Huang
- Science and Technology Department, Southwest University, Chongqing 400715, China;
| | - Yi-Hong Shen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Beibei, Chongqing 400715, China; (X.-L.Z.); (X.-B.Y.); (H.-Y.Z.); (H.W.)
- Correspondence: (Y.-H.S.); (C.L.); Tel.: +86-138-8360-7000 (Y.-H.S.); +86-23-6825-0346 (C.L.)
| | - Cheng Lu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Beibei, Chongqing 400715, China; (X.-L.Z.); (X.-B.Y.); (H.-Y.Z.); (H.W.)
- Correspondence: (Y.-H.S.); (C.L.); Tel.: +86-138-8360-7000 (Y.-H.S.); +86-23-6825-0346 (C.L.)
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Wang S, Wang P. Functional redundancy of structural proteins of the peritrophic membrane in Trichoplusia ni. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 125:103456. [PMID: 32814147 DOI: 10.1016/j.ibmb.2020.103456] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 08/08/2020] [Accepted: 08/10/2020] [Indexed: 06/11/2023]
Abstract
The peritrophic membrane (or peritrophic matrix) (PM) in insects is formed by binding of PM proteins with multiple chitin binding domains (CBDs) to chitin fibrils. Multi-CBD chitin binding proteins (CBPs) and the insect intestinal mucin (IIM) are major PM structural proteins. To understand the biochemical and physiological role of IIM in structural formation and physiological function of the PM, Trichoplusia ni mutant strains lacking IIM were generated by CRISPR/Cas9 mutagenesis. The mutant T. ni larvae were confirmed to lack IIM, but PM formation was observed as in wild type larvae and lacking IIM in the PM did not result in changes of protease activities in the larval midgut. Larval growth and development of the mutant strains were similar to the wild type strain on artificial diet and cabbage leaves, but had a decreased survival in the 5th instar. The larvae of the mutant strains with the PM formed without IIM did not have a change of susceptibility to the infection of the baculovirus AcMNPV and the Bacillus thuringiensis (Bt) formulation Dipel, to the toxicity of the Bt toxins Cry1Ac and Cry2Ab and the chemical insecticide sodium aluminofluoride. Treatment of the mutant T. ni larvae with Calcofluor reduced the larval susceptibility to the toxicity of Bt Cry1Ac, as similarly observed in the wild type larvae. Overall, in the mutant T. ni larvae, the PM was formed without IIM and the lacking of IIM in the PM did not drastically impact the performance of larvae on diet or cabbage leaves under the laboratory conditions.
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Affiliation(s)
- Shaohua Wang
- Department of Entomology, Cornell University, Geneva, NY, 14456, USA; School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Ping Wang
- Department of Entomology, Cornell University, Geneva, NY, 14456, USA.
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Scharf ME. Challenges and physiological implications of wood feeding in termites. CURRENT OPINION IN INSECT SCIENCE 2020; 41:79-85. [PMID: 32823202 DOI: 10.1016/j.cois.2020.07.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 07/26/2020] [Accepted: 07/28/2020] [Indexed: 06/11/2023]
Abstract
Termites are fascinating insects for a number of reasons, one of which being their specialization on diets of wood lignocellulose. The goal of this review is to consider stress-inducing characteristics of wood and apparent molecular-physiological adaptations in termite guts to overcome these stressors. Defensive factors present in wood include extractive secondary plant metabolites, lignin and related phenolics, crystalline cellulose, and low nitrogen content. Molecular-physiological adaptations of the termite gut to deal with these factors include robust detoxification and antioxidant machinery, the production of a peritrophic matrix and a wide range of cellulases from host and symbiotic sources, and creation of niches available to nitrogen-fixing bacterial symbionts. Considering termite gut physiology and symbioses in the context of stress-response has applied implications. These outcomes can include development of efficient biomass breakdown strategies, protection of microbes during industrial processing applications, and safeguarding wooden structures from termite damage.
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Affiliation(s)
- Michael E Scharf
- Department of Entomology, Purdue University, West Lafayette, IN 47907, USA.
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10
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Sousa G, Gandara ACP, Oliveira PL, Gomes FM, Bahia AC, Machado EA. The relationship between oxidant levels and gut physiology in a litter-feeding termite. Sci Rep 2019; 9:670. [PMID: 30679618 PMCID: PMC6345907 DOI: 10.1038/s41598-018-37043-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 11/28/2018] [Indexed: 11/09/2022] Open
Abstract
The termite gut is an efficient decomposer of polyphenol-rich diets, such as lignocellulosic biomasses, and it has been proposed that non-enzymatic oxidative mechanisms could be involved with the digestive process in these animals. However, oxidant levels are completely unknown in termites, as well as protective mechanisms against oxidative damage to the termite gut and its microbiota. As the first step in investigating the role oxidants plays in termite gut physiology, this work presents oxidant levels, antioxidant enzymatic defenses, cell renewal and microbiota abundance along the litter-feeding termite Cornitermes cumulans gut compartments (foregut, midgut, mixed segment and hindgut p1, p3, p4, and p5 segments) and salivary glands. The results show variable levels of oxidants along the C. cumulans gut, the production of antioxidant enzymes, gut cell renewal as potential defenses against oxidative injuries and the profile of microbiota distribution (being predominantly inverse to oxidant levels). In this fashion, the oxidative challenges imposed by polyphenol-rich diet seem to be circumvented by the C. cumulans gut, ensuring efficiency of the digestive process together with preservation of tissue homoeostasis and microbiota growth. These results present new insights into the physicochemical properties of the gut in a litter-feeding termite, expanding our view in relation to termites’ digestive physiology.
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Affiliation(s)
- Gessica Sousa
- Laboratório de Bioquímica de Insetos e Parasitos (Labip), Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ana Caroline P Gandara
- Laboratório de Bioquímica de Artrópodes Hematófagos, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Pedro L Oliveira
- Laboratório de Bioquímica de Artrópodes Hematófagos, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fabio M Gomes
- Laboratory of Malaria and Vector Research, National Institute of Health, Bethesda, United States of America
| | - Ana Cristina Bahia
- Laboratório de Bioquímica de Insetos e Parasitos (Labip), Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ednildo A Machado
- Laboratório de Bioquímica de Insetos e Parasitos (Labip), Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. .,Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular (INCT-EM), Rio de Janeiro, Brazil.
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Wu W, Gu D, Yan S, Li Z. RNA interference of endoglucanases in the formosan subterranean termite Coptotermes formosanus shiraki (Blattodea: Rhinotermitidae) by dsRNA injection or ingestion. JOURNAL OF INSECT PHYSIOLOGY 2019; 112:15-22. [PMID: 30472007 DOI: 10.1016/j.jinsphys.2018.11.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 11/14/2018] [Accepted: 11/21/2018] [Indexed: 06/09/2023]
Abstract
Termites obtain energy and nutrition from wood and wood-related materials by utilizing endogenous and symbiotic cellulases. Endoglucanase is one of the key cellulases in cellulose digestion. Previous studies have shown that the inhibition of the cellulase enzyme system would be a plausible approach for termite control. In the present study, we studied the effect of RNAi on termites by targeting a conserved region of five endoglucanase genes from Coptotermes formosanus (CfEGs). Both dsRNA injection and oral delivery resulted in significant gene silencing of CfEGs and consequently led to mortality, reduced enzyme activity, and reduced weight compared to control worker termites. An injection dose of 150 ng and a feeding dose of 2 μg/cm2 provided for the best RNAi efficiency. dsCfEG was further combined with flufenoxuron, an insect growth regulator used to manage/suppress subterranean termites, and when fed to workers, caused a lower enzyme activity compared to the dsCfEG- or flufenoxuron-only treatment. The weight loss (∼0.598 mg) and mortality (∼28%) observed in the combined dsCfEG and flufenoxuron treatment differed significantly from those observed in the flufenoxuron-only treatment (∼0.208 mg and ∼16%, respectively). Although the effects of these dsCfEG treatments on mortality were insufficient to serve as termiticides, dsCfEGs could be used in combination with other treatments to increase efficacy. This study provides a research basis for the use of RNAi in termiticides.
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Affiliation(s)
- Wenjing Wu
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Guangdong Institute of Applied Biological Resources, 105 Xingang Road West, Guangzhou 510260, PR China
| | - Daifei Gu
- College of Forestry, Northeast Forestry University, No. 26, Hexing Road, Harbin 150040, PR China
| | - Shanchun Yan
- College of Forestry, Northeast Forestry University, No. 26, Hexing Road, Harbin 150040, PR China
| | - Zhiqiang Li
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Guangdong Institute of Applied Biological Resources, 105 Xingang Road West, Guangzhou 510260, PR China.
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Raje KR, Peterson BF, Scharf ME. Screening of 57 Candidate Double-Stranded RNAs for Insecticidal Activity Against the Pest Termite Reticulitermes flavipes (Isoptera: Rhinotermitidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2018; 111:2782-2787. [PMID: 30272186 DOI: 10.1093/jee/toy294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Indexed: 06/08/2023]
Abstract
RNA interference insecticides have received increasing attention in recent years due to their classification as a reduced-risk biopesticide and their proposed faster path to registration compared with conventional synthetic insecticides. The goal of this study was to synthesize and compare efficacy of 62 double-stranded RNAs (dsRNAs) from 31 target genes against the pest termite species, Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae). Fifty-seven dsRNAs of ~125 base pairs each were successfully synthesized. First-tier screens using a combination immersion/feeding assay revealed 10 top candidates and also that dsRNAs coming from synthesis reactions with 80-90× yields were the most effective. Follow-up studies using uptake enhancers in combination with top candidate dsRNAs were unsuccessful. Subsequent concentration range feeding assays on the top candidates revealed two lead termiticidal dsRNAs (3' Hexamerin-2 and 3' Glycosyl Hydrolase Family [GHF] 9-2 cellulase) and another that enhanced feeding (5' GHF9-2 cellulase). Testing a matrix of combinations of these three dsRNAs revealed ultimately that the most consistently effective dsRNA combination was the 3' Hexamerin-2 + 3' GHF9-2 cellulase dsRNA combination. These results provide new information on candidate termiticidal dsRNAs and some apparent factors that have a bearing on their efficacy. Despite these successes, further research and development will be necessary to move dsRNA termiticides from pest management theory to real-world application.
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Affiliation(s)
- Kapil R Raje
- Department of Entomology, Purdue University, West Lafayette, IN
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Wu W, Li Z. dsRNA Injection Successfully Inhibited Two Endogenous β-Glucosidases in Coptotermes formosanus (Isoptera: Rhinotermitidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2018; 111:860-867. [PMID: 29360999 DOI: 10.1093/jee/tox371] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Indexed: 06/07/2023]
Abstract
Cellulose digestion is an essential process of termites, and it is accomplished by three types of cellulases. β-Glucosidase (BG), one of the critical cellulases responsible for cellulose degradation and glucose production, has been considered as a potential target for pest management strategies. Previous experiments identified two new endogenous BG homologs, CfBG-Ia and CfBG-Ib, in the digestive system of Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). The objectives of this study were to assess the impact of RNA interference on CfBG-Ia and CfBG-Ib expression and on termite survival. We tested the expression profiles of worker termites which were injected with gene-specific double-stranded RNA (dsRNA, targeting one gene at a time) and a dsRNA cocktail (targeting CfBG-Ia and CfBG-Ib simultaneously). The expression of CfBG-Ib showed a sharp decline in both dsCfBG-Ib and dsRNA cocktail treatments. The expression of CfBG-Ia reduced quickly and significantly in the dsRNA cocktail treatment; while in dsCfBG-Ia treatment, it decreased on the fifth day. Results showed that treatment with the dsRNA cocktail caused greater inhibition of the transcript expression and a shorter response time. However, the expression of nontarget BG homologs was increased as the target BG homologs were being repressed during the testing period in dsRNA cocktail treatment. These results demonstrate that targeting cellulase-coding genes may be a potential strategy to inhibit termite digestion process, or at least dsRNA cocktails serve as a means for identifying the most susceptible target gene families or biological processes.
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Affiliation(s)
- Wenjing Wu
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Guangdong Institute of Applied Biological Resources, Guangzhou, Guangdong, China
| | - Zhiqiang Li
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Guangdong Institute of Applied Biological Resources, Guangzhou, Guangdong, China
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Darrington M, Dalmay T, Morrison NI, Chapman T. Implementing the sterile insect technique with RNA interference - a review. ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA 2017; 164:155-175. [PMID: 29200471 PMCID: PMC5697603 DOI: 10.1111/eea.12575] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/06/2017] [Indexed: 05/22/2023]
Abstract
We review RNA interference (RNAi) of insect pests and its potential for implementing sterile insect technique (SIT)-related control. The molecular mechanisms that support RNAi in pest species are reviewed in detail, drawing on literature from a range of species including Drosophila melanogaster Meigen and Homo sapiens L. The underlying genes that enable RNAi are generally conserved across taxa, although variance exists in both their form and function. RNAi represents a plausible, non-GM system for targeting populations of insects for control purposes, if RNAi effector molecules can be delivered environmentally (eRNAi). We consider studies of eRNAi from across several insect orders and review to what extent taxonomy, genetics, and differing methods of double-stranded (ds) RNA synthesis and delivery can influence the efficiency of gene knockdown. Several factors, including the secondary structure of the target mRNA and the specific nucleotide sequence of dsRNA effector molecules, can affect the potency of eRNAi. However, taxonomic relationships between insects cannot be used to reliably forecast the efficiency of an eRNAi response. The mechanisms by which insects acquire dsRNA from their environment require further research, but the evidence to date suggests that endocytosis and transport channels both play key roles. Delivery of RNA molecules packaged in intermediary carriers such as bacteria or nanoparticles may facilitate their entry into and through the gut, and enable the evasion of host defence systems, such as toxic pH, that would otherwise attenuate the potential for RNAi.
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Affiliation(s)
- Michael Darrington
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNorfolkNR4 7TJUK
| | - Tamas Dalmay
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNorfolkNR4 7TJUK
| | | | - Tracey Chapman
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNorfolkNR4 7TJUK
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