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Pogačar K, Grundner M, Žigon P, Coll A, Panevska A, Lukan T, Petek M, Razinger J, Gruden K, Sepčić K. Protein complexes from edible mushrooms as a sustainable potato protection against coleopteran pests. PLANT BIOTECHNOLOGY JOURNAL 2024. [PMID: 38733093 DOI: 10.1111/pbi.14365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/08/2024] [Accepted: 04/14/2024] [Indexed: 05/13/2024]
Abstract
Protein complexes from edible oyster mushrooms (Pleurotus sp.) composed of pleurotolysin A2 (PlyA2) and pleurotolysin B (PlyB) exert toxicity in feeding tests against Colorado potato beetle (CPB) larvae, acting through the interaction with insect-specific membrane sphingolipid. Here we present a new strategy for crop protection, based on in planta production of PlyA2/PlyB protein complexes, and we exemplify this strategy in construction of transgenic potato plants of cv Désirée. The transgenics in which PlyA2 was directed to the vacuole and PlyB to the endoplasmic reticulum are effectively protected from infestation by CPB larvae without impacting plant performance. These transgenic plants showed a pronounced effect on larval feeding rate, the larvae feeding on transgenic plants being on average five to six folds lighter than larvae feeding on controls. Further, only a fraction (11%-37%) of the larvae that fed on transgenic potato plants completed their life cycle and developed into adult beetles. Moreover, gene expression analysis of CPB larvae exposed to PlyA2/PlyB complexes revealed the response indicative of a general stress status of larvae and no evidence of possibility of developing resistance due to the functional inactivation of PlyA2/PlyB sphingolipid receptors.
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Affiliation(s)
- Karmen Pogačar
- Department of Biotechnology and Systems Biology, National Institute of Biology, Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Maja Grundner
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Primož Žigon
- Plant Protection Department, Agricultural Institute of Slovenia, Ljubljana, Slovenia
| | - Anna Coll
- Department of Biotechnology and Systems Biology, National Institute of Biology, Ljubljana, Slovenia
| | - Anastasija Panevska
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Tjaša Lukan
- Department of Biotechnology and Systems Biology, National Institute of Biology, Ljubljana, Slovenia
| | - Marko Petek
- Department of Biotechnology and Systems Biology, National Institute of Biology, Ljubljana, Slovenia
| | - Jaka Razinger
- Plant Protection Department, Agricultural Institute of Slovenia, Ljubljana, Slovenia
| | - Kristina Gruden
- Department of Biotechnology and Systems Biology, National Institute of Biology, Ljubljana, Slovenia
| | - Kristina Sepčić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
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Paddock KJ, Dellamano K, Hibbard BE, Shelby KS. eCry3.1Ab-resistant Western Corn Rootworm Larval Midgut Epithelia Respond Minimally to Bt Intoxication. JOURNAL OF ECONOMIC ENTOMOLOGY 2023; 116:263-267. [PMID: 36539338 DOI: 10.1093/jee/toac191] [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: 09/08/2022] [Indexed: 06/17/2023]
Abstract
Insect resistance to toxins derived from Bacillus thuringiensis (Bt) is a major issue in agriculture. Resistance to Bt has been linked to the loss of toxin binding sites within the insect, changes within the gut microbiota, and midgut tissue regeneration. Histopathological documentation of intoxication and resistance to Bt is lacking for rootworms in the genus Diabrotica (Coleoptera: Chrysomelidae), a major target of Bt corn. Here, we document the morphological response of both Bt-resistant and Bt-susceptible larval western corn rootworm, Diabrotica virgifera virgifera LeConte, to intoxication with eCry3.1Ab. Gut lumen structural differences are subtle between the two colonies when feeding on non-Bt corn. However, upon ingestion of Bt-corn roots, susceptible larvae develop symptoms indicative of gut disruption by Bt, whereas resistant larvae incur milder effects. Mild disruption of the peritrophic matrix and gut lumen is accompanied by stem cell proliferation that may lead to midgut tissue regeneration. These results help contextualize the multifaceted nature of Bt-resistance in western corn rootworm for the first time from a histopathological perspective.
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Affiliation(s)
| | | | - Bruce E Hibbard
- Plant Genetics Research Group, USDA-ARS, Columbia, MO, 65211, USA
| | - Kent S Shelby
- Biocontrol of Insect Research Laboratory, USDA-ARS, Columbia, MO, 65211, USA
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3
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Coates BS, Walden KKO, Lata D, Vellichirammal NN, Mitchell RF, Andersson MN, McKay R, Lorenzen MD, Grubbs N, Wang YH, Han J, Xuan JL, Willadsen P, Wang H, French BW, Bansal R, Sedky S, Souza D, Bunn D, Meinke LJ, Miller NJ, Siegfried BD, Sappington TW, Robertson HM. A draft Diabrotica virgifera virgifera genome: insights into control and host plant adaption by a major maize pest insect. BMC Genomics 2023; 24:19. [PMID: 36639634 PMCID: PMC9840275 DOI: 10.1186/s12864-022-08990-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 11/04/2022] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Adaptations by arthropod pests to host plant defenses of crops determine their impacts on agricultural production. The larval host range of western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae), is restricted to maize and a few grasses. Resistance of D. v. virgifera to crop rotation practices and multiple insecticides contributes to its status as the most damaging pest of cultivated maize in North America and Europe. The extent to which adaptations by this pest contributes to host plant specialization remains unknown. RESULTS A 2.42 Gb draft D. v. virgifera genome, Dvir_v2.0, was assembled from short shotgun reads and scaffolded using long-insert mate-pair, transcriptome and linked read data. K-mer analysis predicted a repeat content of ≥ 61.5%. Ortholog assignments for Dvir_2.0 RefSeq models predict a greater number of species-specific gene duplications, including expansions in ATP binding cassette transporter and chemosensory gene families, than in other Coleoptera. A majority of annotated D. v. virgifera cytochrome P450s belong to CYP4, 6, and 9 clades. A total of 5,404 transcripts were differentially-expressed between D. v. virgifera larvae fed maize roots compared to alternative host (Miscanthus), a marginal host (Panicum virgatum), a poor host (Sorghum bicolor) and starvation treatments; Among differentially-expressed transcripts, 1,908 were shared across treatments and the least number were between Miscanthus compared to maize. Differentially-expressed transcripts were enriched for putative spliceosome, proteosome, and intracellular transport functions. General stress pathway functions were unique and enriched among up-regulated transcripts in marginal host, poor host, and starvation responses compared to responses on primary (maize) and alternate hosts. CONCLUSIONS Manual annotation of D. v. virgifera Dvir_2.0 RefSeq models predicted expansion of paralogs with gene families putatively involved in insecticide resistance and chemosensory perception. Our study also suggests that adaptations of D. v. virgifera larvae to feeding on an alternate host plant invoke fewer transcriptional changes compared to marginal or poor hosts. The shared up-regulation of stress response pathways between marginal host and poor host, and starvation treatments may reflect nutrient deprivation. This study provides insight into transcriptomic responses of larval feeding on different host plants and resources for genomic research on this economically significant pest of maize.
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Affiliation(s)
- Brad S. Coates
- grid.508983.fCorn Insects & Crop Genetics Research Unit, USDA-ARS, 2310 Pammel Dr, 532 Science II, Iowa State University, Ames, IA 50011 USA
| | - Kimberly K. O. Walden
- grid.35403.310000 0004 1936 9991Roy J. Carver Biotechnology Center, University of Illinois at Champaign-Urbana, Urbana, IL USA
| | - Dimpal Lata
- grid.62813.3e0000 0004 1936 7806Department of Biology, Illinois Institute of Technology, Chicago, IL USA
| | | | - Robert F. Mitchell
- grid.267474.40000 0001 0674 4543University of Wisconsin Oshkosh, Oshkosh, WI USA
| | - Martin N. Andersson
- grid.4514.40000 0001 0930 2361Department of Biology, Lund University, Lund, Sweden
| | - Rachel McKay
- grid.267474.40000 0001 0674 4543University of Wisconsin Oshkosh, Oshkosh, WI USA
| | - Marcé D. Lorenzen
- grid.40803.3f0000 0001 2173 6074Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC USA
| | - Nathaniel Grubbs
- grid.40803.3f0000 0001 2173 6074Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC USA
| | - Yu-Hui Wang
- grid.40803.3f0000 0001 2173 6074Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC USA
| | - Jinlong Han
- grid.40803.3f0000 0001 2173 6074Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC USA
| | - Jing Li Xuan
- grid.40803.3f0000 0001 2173 6074Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC USA
| | - Peter Willadsen
- grid.40803.3f0000 0001 2173 6074Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC USA
| | - Huichun Wang
- grid.24434.350000 0004 1937 0060Department of Entomology, University of Nebraska, Lincoln, NE USA
| | - B. Wade French
- grid.508981.dIntegrated Crop Systems Research Unit, USDA-ARS, Brookings, SD USA
| | - Raman Bansal
- grid.512850.bUSDA-ARS, San Joaquin Valley Agricultural Sciences Center, Parlier, CA USA
| | - Sammy Sedky
- grid.512850.bUSDA-ARS, San Joaquin Valley Agricultural Sciences Center, Parlier, CA USA
| | - Dariane Souza
- grid.15276.370000 0004 1936 8091Department of Entomology, University of Florida, Gainesville, FL USA
| | - Dakota Bunn
- grid.62813.3e0000 0004 1936 7806Department of Biology, Illinois Institute of Technology, Chicago, IL USA
| | - Lance J. Meinke
- grid.24434.350000 0004 1937 0060Department of Entomology, University of Nebraska, Lincoln, NE USA
| | - Nicholas J. Miller
- grid.62813.3e0000 0004 1936 7806Department of Biology, Illinois Institute of Technology, Chicago, IL USA
| | - Blair D. Siegfried
- grid.15276.370000 0004 1936 8091Department of Entomology, University of Florida, Gainesville, FL USA
| | - Thomas W. Sappington
- grid.508983.fCorn Insects & Crop Genetics Research Unit, USDA-ARS, 2310 Pammel Dr, 532 Science II, Iowa State University, Ames, IA 50011 USA
| | - Hugh M. Robertson
- grid.35403.310000 0004 1936 9991Department of Entomology, University of Illinois at Champaign-Urbana, Urbana, IL USA
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Edrington T, Wang R, McKinnon L, Kessenich C, Hodge-Bell K, Li W, Tan J, Brown G, Wang C, Li B, Giddings K. Food and feed safety of the Bacillus thuringiensis derived protein Vpb4Da2, a novel protein for control of western corn rootworm. PLoS One 2022; 17:e0272311. [PMID: 35921368 PMCID: PMC9348738 DOI: 10.1371/journal.pone.0272311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 07/18/2022] [Indexed: 11/30/2022] Open
Abstract
Western corn rootworm (WCR), Diabrotica virgifera virgifera, LeConte, is an insect pest that poses a significant threat to the productivity of modern agriculture, causing significant economic and crop losses. The development of genetically modified (GM) crops expressing one or more proteins that confer tolerance to specific insect pests, such as WCR, was a historic breakthrough in agricultural biotechnology and continues to serve as an invaluable tool in pest management. Despite this, evolving resistance to existing insect control proteins expressed in current generation GM crops requires continued identification of new proteins with distinct modes of action while retaining targeted insecticidal efficacy. GM crops expressing insecticidal proteins must undergo extensive safety assessments prior to commercialization to ensure that they pose no increased risk to the health of humans or other animals relative to their non-GM conventional counterparts. As part of these safety evaluations, a weight of evidence approach is utilized to assess the safety of the expressed insecticidal proteins to evaluate any potential risk in the context of dietary exposure. This study describes the food and feed safety assessment of Vpb4Da2, a new Bacillus thuringiensis insecticidal protein that confers in planta tolerance to WCR. Vpb4Da2 exhibits structural and functional similarities to other insect control proteins expressed in commercialized GM crops. In addition, the lack of homology to known toxins or allergens, a lack of acute toxicity in mice, inactivation by conditions commonly experienced in the human gut or during cooking/food processing, and the extremely low expected dietary exposure to Vpb4Da2 provide a substantial weight of evidence to demonstrate that the Vpb4Da2 protein poses no indication of a risk to the health of humans or other animals.
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Affiliation(s)
| | - Rong Wang
- Bayer Crop Science, Chesterfield, MO, United States of America
- * E-mail:
| | - Lucas McKinnon
- Bayer Crop Science, Chesterfield, MO, United States of America
| | | | | | - Wenze Li
- Bayer Crop Science, Chesterfield, MO, United States of America
| | - Jianguo Tan
- Bayer Crop Science, Chesterfield, MO, United States of America
| | - Gregory Brown
- Bayer Crop Science, Chesterfield, MO, United States of America
| | - Cunxi Wang
- Bayer Crop Science, Chesterfield, MO, United States of America
| | - Bin Li
- Bayer Crop Science, Chesterfield, MO, United States of America
| | - Kara Giddings
- Bayer Crop Science, Chesterfield, MO, United States of America
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5
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Coates BS, Deleury E, Gassmann AJ, Hibbard BE, Meinke LJ, Miller NJ, Petzold-Maxwell J, French BW, Sappington TW, Siegfried BD, Guillemaud T. Up-regulation of apoptotic- and cell survival-related gene pathways following exposures of western corn rootworm to B. thuringiensis crystalline pesticidal proteins in transgenic maize roots. BMC Genomics 2021; 22:639. [PMID: 34479486 PMCID: PMC8418000 DOI: 10.1186/s12864-021-07932-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 08/04/2021] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Resistance of pest insect species to insecticides, including B. thuringiensis (Bt) pesticidal proteins expressed by transgenic plants, is a threat to global food security. Despite the western corn rootworm, Diabrotica virgifera virgifera, being a major pest of maize and having populations showing increasing levels of resistance to hybrids expressing Bt pesticidal proteins, the cell mechanisms leading to mortality are not fully understood. RESULTS Twenty unique RNA-seq libraries from the Bt susceptible D. v. virgifera inbred line Ped12, representing all growth stages and a range of different adult and larval exposures, were assembled into a reference transcriptome. Ten-day exposures of Ped12 larvae to transgenic Bt Cry3Bb1 and Gpp34/Tpp35Ab1 maize roots showed significant differential expression of 1055 and 1374 transcripts, respectively, compared to cohorts on non-Bt maize. Among these, 696 were differentially expressed in both Cry3Bb1 and Gpp34/Tpp35Ab1 maize exposures. Differentially-expressed transcripts encoded protein domains putatively involved in detoxification, metabolism, binding, and transport, were, in part, shared among transcripts that changed significantly following exposures to the entomopathogens Heterorhabditis bacteriophora and Metarhizium anisopliae. Differentially expressed transcripts in common between Bt and entomopathogen treatments encode proteins in general stress response pathways, including putative Bt binding receptors from the ATP binding cassette transporter superfamily. Putative caspases, pro- and anti-apoptotic factors, as well as endoplasmic reticulum (ER) stress-response factors were identified among transcripts uniquely up-regulated following exposure to either Bt protein. CONCLUSIONS Our study suggests that the up-regulation of genes involved in ER stress management and apoptotic progression may be important in determining cell fate following exposure of susceptible D. v. virgifera larvae to Bt maize roots. This study provides novel insights into insect response to Bt intoxication, and a possible framework for future investigations of resistance mechanisms.
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Affiliation(s)
- Brad S Coates
- USDA-ARS, Corn Insects & Crop Genetics Research Unit, 103 Genetics Laboratory, Iowa State University, Ames, IA, 50011, USA.
| | | | | | | | - Lance J Meinke
- Department of Entomology, University of Nebraska, Lincoln, NE, USA
| | | | | | - B Wade French
- USDA-ARS, North Central Agricultural Research Laboratory, Brookings, SD, USA
| | - Thomas W Sappington
- USDA-ARS, Corn Insects & Crop Genetics Research Unit, 103 Genetics Laboratory, Iowa State University, Ames, IA, 50011, USA
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6
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Zhao Z, Elsik CG, E Hibbard B, S Shelby K. Detection of alternative splicing in western corn rootworm (Diabrotica virgifera virgifera LeConte) in association with eCry3.1Ab resistance using RNA-seq and PacBio Iso-Seq. INSECT MOLECULAR BIOLOGY 2021; 30:436-445. [PMID: 33955085 DOI: 10.1111/imb.12709] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 05/01/2021] [Indexed: 06/12/2023]
Abstract
Alternative splicing is a common feature in eukaryotes that not only increases the transcript diversity, but also has functional consequences. In insects, alternative splicing has been found associated with resistance to pesticides and Bt toxins. Up to date, the alternative splicing in western corn rootworm (Diabrotica virgifera virgifera LeConte) has not been studied. To investigate its alternative splicing pattern and relation to Bt resistance, we carried out single-molecule real-time (SMRT) transcript sequencing and Iso-seq analysis on resistant, eCry3.1Ab-selected and susceptible, unselected, western corn rootworm neonate midguts which fed on seedling maize with and without eCry3.1Ab for 12 and 24 h. We present transcriptome-wide alternative splicing patterns of western corn rootworm midgut in response to feeding on eCry3.1Ab-expressing corn using a comprehensive approach that combines both RNA-seq and SMRT transcript sequencing techniques. The results showed genes in western corn rootworm are highly alternatively spliced, which happens on 67.73% of multi-exon genes. One of the alternative splicing events we identified was a novel peritrophic matrix protein with two alternative splicing isoforms. Analysis of differential exon usage between resistant and susceptible colonies showed that in eCry3.1Ab-resistant western corn rootworm, expression of one isoform was significantly higher than in the susceptible colony, while no significant differences between colonies were observed with the other isoform. Our results provide the first survey of alternative splicing in western corn rootworm and suggest that the observed alternatively spliced isoforms of peritrophic matrix protein may be associated with eCry3.1Ab resistance in western corn rootworm.
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Affiliation(s)
- Z Zhao
- Division of Plant Sciences, University of Missouri, Columbia, MO, USA
| | - C G Elsik
- Division of Plant Sciences, University of Missouri, Columbia, MO, USA
- Division of Animal Sciences, University of Missouri, Columbia, MO, USA
- Institute for Data Science and Informatics, University of Missouri, Columbia, MO, USA
| | - B E Hibbard
- Division of Plant Sciences, University of Missouri, Columbia, MO, USA
- USDA-ARS Plant Genetics Research Unit, Columbia, MO, USA
| | - K S Shelby
- Division of Plant Sciences, University of Missouri, Columbia, MO, USA
- USDA-ARS Biological Control of Insects Research Laboratory, Columbia, MO, USA
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7
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Liu L, Li Z, Luo X, Zhang X, Chou SH, Wang J, He J. Which Is Stronger? A Continuing Battle Between Cry Toxins and Insects. Front Microbiol 2021; 12:665101. [PMID: 34140940 PMCID: PMC8203666 DOI: 10.3389/fmicb.2021.665101] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 04/20/2021] [Indexed: 12/20/2022] Open
Abstract
In this article, we review the latest works on the insecticidal mechanisms of Bacillus thuringiensis Cry toxins and the resistance mechanisms of insects against Cry toxins. Currently, there are two models of insecticidal mechanisms for Cry toxins, namely, the sequential binding model and the signaling pathway model. In the sequential binding model, Cry toxins are activated to bind to their cognate receptors in the mid-intestinal epithelial cell membrane, such as the glycophosphatidylinositol (GPI)-anchored aminopeptidases-N (APNs), alkaline phosphatases (ALPs), cadherins, and ABC transporters, to form pores that elicit cell lysis, while in the signaling pathway model, the activated Cry toxins first bind to the cadherin receptor, triggering an extensive cell signaling cascade to induce cell apoptosis. However, these two models cannot seem to fully describe the complexity of the insecticidal process of Cry toxins, and new models are required. Regarding the resistance mechanism against Cry toxins, the main method insects employed is to reduce the effective binding of Cry toxins to their cognate cell membrane receptors by gene mutations, or to reduce the expression levels of the corresponding receptors by trans-regulation. Moreover, the epigenetic mechanisms, host intestinal microbiota, and detoxification enzymes also play significant roles in the insects' resistance against Cry toxins. Today, high-throughput sequencing technologies like transcriptomics, proteomics, and metagenomics are powerful weapons for studying the insecticidal mechanisms of Cry toxins and the resistance mechanisms of insects. We believe that this review shall shed some light on the interactions between Cry toxins and insects, which can further facilitate the development and utilization of Cry toxins.
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Affiliation(s)
- Lu Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Zhou Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xing Luo
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xia Zhang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.,Department of Molecular Biology, Qingdao Vland Biotech Inc., Qingdao, China
| | - Shan-Ho Chou
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jieping Wang
- Agricultural Bioresources Institute, Fujian Academy of Agricultural Sciences, Fuzhou, China
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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8
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Jurat-Fuentes JL, Heckel DG, Ferré J. Mechanisms of Resistance to Insecticidal Proteins from Bacillus thuringiensis. ANNUAL REVIEW OF ENTOMOLOGY 2021; 66:121-140. [PMID: 33417820 DOI: 10.1146/annurev-ento-052620-073348] [Citation(s) in RCA: 116] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) are used in sprayable formulations or produced in transgenic crops as the most successful alternatives to synthetic pesticides. The most relevant threat to sustainability of Bt insecticidal proteins (toxins) is the evolution of resistance in target pests. To date, high-level resistance to Bt sprays has been limited to one species in the field and another in commercial greenhouses. In contrast, there are currently seven lepidopteran and one coleopteran species that have evolved practical resistance to transgenic plants producing insecticidal Bt proteins. In this article, we present a review of the current knowledge on mechanisms of resistance to Bt toxins, with emphasis on key resistance genes and field-evolved resistance, to support improvement of Bt technology and its sustainability.
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Affiliation(s)
- Juan Luis Jurat-Fuentes
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, Tennessee 37996, USA;
| | - David G Heckel
- Department of Entomology, Max Planck Institute for Chemical Ecology, Jena 07745, Germany;
| | - Juan Ferré
- ERI of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot 46100, Spain;
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9
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Ren Y, Zhou X, Dong Y, Zhang J, Wang J, Yang M. Exogenous Gene Expression and Insect Resistance in Dual Bt Toxin Populus × euramericana 'Neva' Transgenic Plants. FRONTIERS IN PLANT SCIENCE 2021; 12:660226. [PMID: 34122482 PMCID: PMC8193859 DOI: 10.3389/fpls.2021.660226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 05/03/2021] [Indexed: 05/07/2023]
Abstract
Bacillus thuringiensis (Bt) insecticidal protein genes are important tools in efforts to develop insect resistance in poplar. In this study, the Cry1Ac and Cry3A Bt toxin genes were simultaneously transformed into the poplar variety Populus × euramericana 'Neva' by Agrobacterium-mediated transformation to explore the exogenous gene expression and insect resistance, and to examine the effects of Bt toxin on the growth and development of Anoplophora glabripennis larvae after feeding on the transgenic plant. Integration and expression of the transgenes were determined by molecular analyses and the insect resistance of transgenic lines was evaluated in feeding experiments. Sixteen transgenic dual Bt toxin genes Populus × euramericana 'Neva' lines were obtained. The dual Bt toxin genes were expressed at both the transcriptional and translational levels; however, Cry3A protein levels were much higher than those of Cry1Ac. Some of the transgenic lines exhibited high resistance to the first instar larvae of Hyphantria cunea and Micromelalopha troglodyta, and the first and second instar larvae and adults of Plagiodera versicolora. Six transgenic lines inhibited the growth and development of A. glabripennis larvae. The differences in the transcriptomes of A. glabripennis larvae fed transgenic lines or non-transgenic control by RNA-seq analyses were determined to reveal the mechanism by which Bt toxin regulates the growth and development of longicorn beetle larvae. The expression of genes related to Bt prototoxin activation, digestive enzymes, binding receptors, and detoxification and protective enzymes showed significant changes in A. glabripennis larvae fed Bt toxin, indicating that the larvae responded by regulating the expression of genes related to their growth and development. This study lay a theoretical foundation for developing resistance to A. glabripennis in poplar, and provide a foundation for exploring the mechanism of Bt toxin action on Cerambycidae insects.
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Affiliation(s)
- Yachao Ren
- Forest Department, Forestry College, Hebei Agricultural University, Baoding, China
- Hebei Key Laboratory for Tree Genetic Resources and Forest Protection, Baoding, China
| | - Xinglu Zhou
- Forest Department, Forestry College, Hebei Agricultural University, Baoding, China
- Hebei Key Laboratory for Tree Genetic Resources and Forest Protection, Baoding, China
| | - Yan Dong
- Forest Department, Forestry College, Hebei Agricultural University, Baoding, China
- Hebei Key Laboratory for Tree Genetic Resources and Forest Protection, Baoding, China
| | - Jun Zhang
- Forest Department, Forestry College, Hebei Agricultural University, Baoding, China
- Hebei Key Laboratory for Tree Genetic Resources and Forest Protection, Baoding, China
| | - Jinmao Wang
- Forest Department, Forestry College, Hebei Agricultural University, Baoding, China
- Hebei Key Laboratory for Tree Genetic Resources and Forest Protection, Baoding, China
| | - Minsheng Yang
- Forest Department, Forestry College, Hebei Agricultural University, Baoding, China
- Hebei Key Laboratory for Tree Genetic Resources and Forest Protection, Baoding, China
- *Correspondence: Minsheng Yang,
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10
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Functional validation of DvABCB1 as a receptor of Cry3 toxins in western corn rootworm, Diabrotica virgifera virgifera. Sci Rep 2020; 10:15830. [PMID: 32985523 PMCID: PMC7522262 DOI: 10.1038/s41598-020-72572-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/03/2020] [Indexed: 02/03/2023] Open
Abstract
Western corn rootworm (WCR), Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae), is a serious insect pest in the major corn growing areas of North America and in parts of Europe. WCR populations with resistance to Bacillus thuringiensis (Bt) toxins utilized in commercial transgenic traits have been reported, raising concerns over their continued efficacy in WCR management. Understanding the modes of action of Bt toxins is important for WCR control and resistance management. Although different classes of proteins have been identified as Bt receptors for lepidopteran insects, identification of receptors in WCR has been limited with no reports of functional validation. Our results demonstrate that heterologous expression of DvABCB1 in Sf9 and HEK293 cells conferred sensitivity to the cytotoxic effects of Cry3A toxins. The result was further validated using knockdown of DvABCB1 by RNAi which rendered WCR larvae insensitive to a Cry3A toxin. However, silencing of DvABCB2 which is highly homologous to DvABCB1 at the amino acid level, did not reduce the sensitivity of WCR larvae to a Cry3A toxin. Furthermore, our functional studies corroborate different mode-of-actions for other insecticidal proteins including Cry34Ab1/35Ab1, Cry6Aa1, and IPD072Aa against WCR. Finally, reduced expression and alternatively spliced transcripts of DvABCB1 were identified in a mCry3A-resistant strain of WCR. Our results provide the first clear demonstration of a functional receptor in the molecular mechanism of Cry3A toxicity in WCR and confirmed its role in the mechanism of resistance in a mCry3A resistant strain of WCR.
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