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Li H, Deng L, Weng L, Li J, Hu W, Yu J, Xiao Y, Xiao G. Cell wall-localized Bt protein endows rice high resistance to Lepidoptera pests. PEST MANAGEMENT SCIENCE 2024; 80:1728-1739. [PMID: 38009289 DOI: 10.1002/ps.7901] [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: 06/27/2023] [Revised: 11/14/2023] [Accepted: 11/27/2023] [Indexed: 11/28/2023]
Abstract
BACKGROUND The commercialized Bt (Bacillus thuringiensis) crops accumulate Bt protein within cells, but the intracellular interactions of foreign protein with endogenous protein inevitably result in large or small unintended effects. In this study, the Bt gene Cry1Ca was linked with the sequences of extracellular secretion signal peptide and carbohydrate binding module 11 to constitute a fusion gene SP-Cry1Ca-CBM11, and the fusion gene driven by constitutive promoters was used for secreting and anchoring onto the cell wall to minimize unintended effects. RESULTS The transient expression in tobacco leaves demonstrated that the fusion protein was anchored on cell walls. The Cry1Ca contents of five homozygous rice transformants of single-copy insertion were different and descended in the order leaf > root > stem. The maximum content of Cry1Ca was 17.55 μg g-1 in leaves of transformant 21H037. The bioassay results revealed that the transformants exhibited high resistance to lepidopteran pests. The corrected mortality of pink stem borer (Sesamia inferens) and striped stem borer (Chilo suppressalis) ranged from 96.33% to 100%, and from 83.32% to 100%, respectively, and the corrected mortality of rice leaf roller (Cnaphalocrocis medinalis) was 92.53%. Besides, the agronomic traits of the five transformants were normal and similar to that of the recipient, and the transformants were highly resistant to glyphosate at the germination and seedling stages. CONCLUSION The fusion Bt protein was accumulated on cell walls and endowed the rice with high resistance to lepidopteran pests without unintended effects in agronomic traits. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Hua Li
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Lihua Deng
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
| | - Lvshui Weng
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
| | - Jinjiang Li
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
| | - Wenbin Hu
- Hunan Academy of Agricultural Sciences, Changsha, China
| | - Jianghui Yu
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
| | - Youlun Xiao
- Hunan Academy of Agricultural Sciences, Changsha, China
| | - Guoying Xiao
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
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Oyediran I, Rice ME, Conville J, Boudreau E, Morsello S, Burd T. Bt corn hybrids expressing mCry3A and eCry3.1Ab Proteins protect corn roots against western corn rootworm injury. PEST MANAGEMENT SCIENCE 2023; 79:4839-4846. [PMID: 37489843 DOI: 10.1002/ps.7680] [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: 04/26/2023] [Revised: 07/21/2023] [Accepted: 07/25/2023] [Indexed: 07/26/2023]
Abstract
BACKGROUND The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is one of the most serious pests of corn (Zea mays L.) In 2017 and 2018, studies were conducted in fields with and without known unexpected root injury to Cry3Bb1, to determine root protection by Bt corn hybrids expressing both mCry3A and eCry3.1Ab insecticidal crystal proteins, and hybrids expressing either mCry3A or eCry3.1Ab only against the WCR root injury. Node injury was evaluated using the Iowa State University 0-3 node-injury scale (NIS), and the consistency of root protection was also determined. RESULTS In 2017, with medium to high larval feeding pressure, the Bt corn hybrids expressing both mCry3A and eCry3.1Ab in the breeding stack, molecular stack, and Bt corn hybrid expressing eCry3.1Ab only, sustained low node injury compared with Bt corn hybrid expressing mCry3A only, and the non-Bt corn. In 2018, with low larval feeding pressure in most of the locations, node injury was not different for the Bt and Non-Bt corn hybrids. Across all locations in both years, the Bt corn hybrids expressing both mCry3A and eCry3.1Ab provided better and consistent node injury protection. CONCLUSION Bt corn hybrids expressing both mCry3A and eCry3.1Ab proteins provided better root protection and consistency than the Bt corn hybrid expressing mCry3A only, and non-Bt. Therefore, stacking of Bt traits will be the best option for managing insect resistance. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Isaac Oyediran
- Syngenta Crop Protection LLC, Research Triangle Park, North Carolina, USA
| | - Marlin E Rice
- Syngenta Crop Protection LLC, Research Triangle Park, North Carolina, USA
| | - Jared Conville
- Syngenta Crop Protection LLC, Research Triangle Park, North Carolina, USA
| | - Eric Boudreau
- Syngenta Crop Protection LLC, Research Triangle Park, North Carolina, USA
| | | | - Tony Burd
- Syngenta Crop Protection LLC, Greensboro, North Carolina, USA
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Geisert RW, Huynh MP, Pereira AE, Shapiro Ilan DI, Hibbard BE. An improved bioassay for the testing of entomopathogenic nematode virulence to the western corn rootworm (Diabrotica virgifera virgifera) (Coleoptera: Chrysomelidae): with focus on neonate insect assessments. JOURNAL OF ECONOMIC ENTOMOLOGY 2023; 116:726-732. [PMID: 37021702 DOI: 10.1093/jee/toad052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 02/20/2023] [Accepted: 03/06/2023] [Indexed: 06/14/2023]
Abstract
Bioassays involving newly hatched larval insects can be limited by the larvae's feeding state. Assays attempting to monitor mortality effects can be negatively affected by starvation effects on the larvae. Neonate western corn rootworms have significant reductions in viability if not provided food within 24 h post hatch. The recent development of an improved artificial diet for western corn rootworm larvae provides a new bioassay type for evaluating entomopathogenic nematodes that also makes the testing arena easy to observe. Here, we evaluated four species of entomopathogenic nematodes including Heterorhabditis bacteriophora Poinar, Steinernema carpocapsae (Weiser), Steinernema diaprepesi Nguyen & Duncan, and Steinernema rarum (de Doucet) against neonate western corn rootworm, Diabrotica virgifera virgifera LeConte, in 96-well plate diet bioassays. Nematode inoculation levels were 0, 15, 30, 60, and 120 nematodes per larva. Percentage mortality increased for each species as the rate of inoculation increased. Overall, H. bacteriophora and S. carpocapsae caused the greatest amount of larval mortality. The diet-based bioassays were shown to be an effective method for nematode exposure to insect pests. The assays provided adequate moisture to keep nematode from desiccating while also allowing freedom of movement around the arenas. Both rootworm larvae and nematodes were contained within the assay arenas. The addition of nematodes did not cause any significant deterioration of the diet within the three-day period of testing. Overall, the diet bioassays worked well as a measure of entomopathogenic nematode virulence.
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Affiliation(s)
- Ryan W Geisert
- Division of Plant Science & Technology, University of Missouri, Columbia, MO, USA
| | - Man P Huynh
- Division of Plant Science & Technology, University of Missouri, Columbia, MO, USA
- Department of Plant Protection, Can Tho University, Can Tho, Vietnam
| | - Adriano E Pereira
- Plant Genetics Research Unit, USDA-Agricultural Research Service, Columbia, MO, USA
| | - David I Shapiro Ilan
- David I Shapiro Ilan, USDA-ARS, Fruit and Tree Nut Research Station, Byron, GA, USA
| | - Bruce E Hibbard
- Plant Genetics Research Unit, USDA-Agricultural Research Service, Columbia, MO, USA
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Pereira AE, Geisert RW, Hibbard BE. Maize Inbred Mp708 is Highly Susceptible to Western Corn Rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae), in Field and Greenhouse Assays. JOURNAL OF INSECT SCIENCE (ONLINE) 2022; 22:8. [PMID: 36480227 PMCID: PMC9731326 DOI: 10.1093/jisesa/ieac067] [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: 08/01/2022] [Indexed: 06/17/2023]
Abstract
The western corn rootworm (WCR), Diabrotica vifgirera virgifera LeConte, (Coleoptera: Chrysomelidae) causes significant economic damage in corn production each year. Resistance to insecticides and transgenic corn with Bacillus thuringiensis (Bt), Berliner toxins have been reported throughout the United States Corn Belt. Corn breeding programs for natural resistance against WCR larvae could potentially assist in rootworm management. Root damage and root regrowth of eight corn lines were evaluated in field assays at three different locations. Results indicated the inbred 'Mp708' had the greatest root damage and was significantly greater than damage for the susceptible control, B37×H84. In greenhouse assays, we evaluated four of these lines plus a hybrid expressing the mCry3A Bt toxin for damage. The results indicated that Mp708 had significantly higher root damage when compared to 'CRW3(S1)C6' and 'MIR604'. Despite previous work suggesting otherwise, we conclude that Mp708 is highly susceptible to the WCR larvae based on root damage in field and greenhouse plant assays.
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Affiliation(s)
| | - Ryan W Geisert
- Division of Plant Sciences & Technology, University of Missouri, Columbia, MO, 65211, USA
| | - Bruce E Hibbard
- USDA/ARS, University of Missouri, 205 Curtis Hall, Columbia, MO, 65211, USA
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Kuwar SS, Mishra R, Banerjee R, Milligan J, Rydel T, Du Z, Xie Z, Ivashuta S, Kouadio JL, Meyer JM, Bonning BC. Engineering of Cry3Bb1 provides mechanistic insights toward countering western corn rootworm resistance. CURRENT RESEARCH IN INSECT SCIENCE 2022; 2:100033. [PMID: 36003270 PMCID: PMC9387510 DOI: 10.1016/j.cris.2022.100033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 11/28/2022]
Abstract
Cry3Bb1 engineering for receptor retargeting to counter WCR resistance described Phage display screens against BBMV or recombinant insecticidal-protein receptors 77 gut binding peptides selected and engineered into 284 new variants of Cry3Bb1 112 variants were active against susceptible but not resistant WCR Engineering of Cry3Bb1 Domain II loops 1 and 2 disrupted insecticidal activity Sites for Cry3Bb1 engineering and implications for Cry3Bb1 resistance discussed
The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is an economically important pest of corn (maize) in North America and Europe. Current management practices for WCR involve transgenic expression of insecticidal proteins to minimize larval feeding damage to corn roots. The evolution of resistant WCR populations to transgenic corn expressing insecticidal proteins (e.g. Cry3Bb1, Gpp34Ab1/Tpp35Ab1) necessitates efforts to discover and deploy new modes of action for WCR control. Here, we tested the hypothesis that the addition of short peptides selected for binding to the WCR gut would restore insecticidal activity of Cry3Bb1 to resistant insects. Phage display technology coupled with deep sequencing was used to identify peptides selected for binding to WCR brush border membrane vesicles and to recombinant putative receptors aminopeptidase and cadherin. The binding and specificity of selected peptides was confirmed by ELISA and pull-down assays, and candidate gut surface binding partners were identified. Although production of 284 novel Cry3Bb1 variants with these peptides did not restore activity against resistant WCR in artificial diet bioassays, 112 variants were active against susceptible insects. These results provided insights for the mechanism of Cry3Bb1 activity and toward engineering a new mode-of-action via receptor re-targeting in the context of protein structure and function.
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Affiliation(s)
- Suyog S. Kuwar
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA
| | - Ruchir Mishra
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA
| | - Rahul Banerjee
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA
| | - Jason Milligan
- Bayer U.S., Research and Development, Crop Science Plant Biotechnology, Chesterfield, MO, 63017 USA
| | - Timothy Rydel
- Bayer U.S., Research and Development, Crop Science Plant Biotechnology, Chesterfield, MO, 63017 USA
| | - Zijin Du
- Bayer U.S., Research and Development, Crop Science Plant Biotechnology, Chesterfield, MO, 63017 USA
| | - Zhidong Xie
- Bayer U.S., Research and Development, Crop Science Plant Biotechnology, Chesterfield, MO, 63017 USA
| | - Sergey Ivashuta
- Bayer U.S., Research and Development, Crop Science Plant Biotechnology, Chesterfield, MO, 63017 USA
| | - Jean-Louis Kouadio
- Bayer U.S., Research and Development, Crop Science Plant Biotechnology, Chesterfield, MO, 63017 USA
| | - Jason M. Meyer
- Bayer U.S., Research and Development, Crop Science Plant Biotechnology, Chesterfield, MO, 63017 USA
| | - Bryony C. Bonning
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA
- Corresponding author: Department of Entomology and Nematology, University of Florida, PO Box 110620, Gainesville, FL 32611.
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Rodríguez-González Á, Porteous-Álvarez AJ, Guerra M, González-López Ó, Casquero PA, Escriche B. Effect of Cry Toxins on Xylotrechus arvicola (Coleoptera: Cerambycidae) Larvae. INSECTS 2021; 13:insects13010027. [PMID: 35055870 PMCID: PMC8778931 DOI: 10.3390/insects13010027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/20/2021] [Accepted: 12/24/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary Xylotrechus arvicola is a destructive pest in vineyards (Vitis vinifera) in the main wine-producing areas of the Iberian Peninsula. X. arvicola larvae bore into the grapevine wood-making galleries, thus damaging the plant both directly and indirectly. The susceptibility of X. arvicola larvae to five coleopteran toxic Cry proteins was evaluated under laboratory conditions in order to deepen the knowledge of the effect of these proteins on this insect throughout its biological development. The Cry proteins tested could be applied to control X. arvicola larvae since they were able to kill them and cause serious alterations in the larvae during the remaining months of development that followed. The data presented suggest that these Cry proteins can be used as bioinsecticides against the larvae of this insect, in order to avoid the rapid evolution of resistance against these toxins since not all of the larvae were killed and thus increase vine wood protection. Abstract The beetle Xylotrechus arvicola is a destructive pest in vineyards (Vitis vinifera) in the main wine-producing areas of the Iberian Peninsula. X. arvicola larvae bore into the grapevine wood-making galleries, thus damaging the plant both directly and indirectly; the latter through the proliferation of wood fungi, which can invade the inside of the plant, decreasing the quality and quantity of its production. The susceptibility of X. arvicola larvae to five coleopteran toxic Cry proteins (Cry1B, Cry1I, Cry3A, Cry7A, and Cry23/37) was evaluated under laboratory conditions in order to deepen the knowledge of the effect of these proteins on this insect throughout its biological development. Cry7Ab and Cry1Ba were the most effective in controlling X. arvicola larvae due to the significant reduction in larvae survival (32.9 and 25.9 days, respectively), and by causing serious alterations in the larvae during the remaining months of their development. The developmental stage of the prepupal and pupal stages was not affected by the previous ingestion of Cry proteins. The Cry proteins tested could be applied to control X. arvicola larvae since they were able to kill them and cause serious alterations in the larvae during the remaining months of development that followed. The data presented suggest that these Cry proteins can be used as bioinsecticides against the larvae of this insect, applying them only at the moment when the larvae hatch from the egg outside the grapevine wood (this would only be useful and justified if the economic threshold is exceeded) in order to avoid the rapid evolution of resistance against these toxins since not all of the larvae were killed and thus increase vine wood protection.
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Affiliation(s)
- Álvaro Rodríguez-González
- Grupo Universitario de Investigación en Ingeniería y Agricultura Sostenible (GUIIAS), Instituto de Medio Ambiente Recursos Naturales y Biodiversidad (INMARENBIO), Escuela de Ingeniería Agraria y Forestal (EIAF), Universidad de León, 24071 Leon, Spain; (A.J.P.-Á.); (P.A.C.)
- Correspondence: (Á.R.-G.); (B.E.)
| | - Alejandra J. Porteous-Álvarez
- Grupo Universitario de Investigación en Ingeniería y Agricultura Sostenible (GUIIAS), Instituto de Medio Ambiente Recursos Naturales y Biodiversidad (INMARENBIO), Escuela de Ingeniería Agraria y Forestal (EIAF), Universidad de León, 24071 Leon, Spain; (A.J.P.-Á.); (P.A.C.)
| | - Marcos Guerra
- Grupo Universitario de Investigación en Ingeniería y Agricultura Sostenible (GUIIAS), Escuela de Ingeniería Agraria y Forestal (EIAF), Campus de Ponferrada, Universidad de León, 24401 Ponferrada, Spain;
| | - Óscar González-López
- Departamento de Agricultura y Alimentación, Complejo Científico Tecnológico, Universidad de La Rioja, Área de Producción Vegetal, 26006 Logrono, Spain;
| | - Pedro A. Casquero
- Grupo Universitario de Investigación en Ingeniería y Agricultura Sostenible (GUIIAS), Instituto de Medio Ambiente Recursos Naturales y Biodiversidad (INMARENBIO), Escuela de Ingeniería Agraria y Forestal (EIAF), Universidad de León, 24071 Leon, Spain; (A.J.P.-Á.); (P.A.C.)
| | - Baltasar Escriche
- Instituto Universitario de Biotecnología y Biomedicina (BIOTECMED), Departamento de Genética, Universitat de Valencia, 46100 Burjassot, Spain
- Correspondence: (Á.R.-G.); (B.E.)
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Kouadio JL, Zheng M, Aikins M, Duda D, Duff S, Chen D, Zhang J, Milligan J, Taylor C, Mamanella P, Rydel T, Kessenich C, Panosian T, Yin Y, Moar W, Giddings K, Park Y, Jerga A, Haas J. Structural and functional insights into the first Bacillus thuringiensis vegetative insecticidal protein of the Vpb4 fold, active against western corn rootworm. PLoS One 2021; 16:e0260532. [PMID: 34928980 PMCID: PMC8687597 DOI: 10.1371/journal.pone.0260532] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 11/11/2021] [Indexed: 01/09/2023] Open
Abstract
The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is a major maize pest in the United States causing significant economic loss. The emergence of field-evolved resistant WCR to Bacillus thuringiensis (Bt) traits has prompted the need to discover and deploy new insecticidal proteins in transgenic maize. In the current study we determined the crystal structure and mode of action (MOA) of the Vpb4Da2 protein (formerly known as Vip4Da2) from Bt, the first identified insecticidal Vpb4 protein with commercial level control against WCR. The Vpb4Da2 structure exhibits a six-domain architecture mainly comprised of antiparallel β-sheets organized into β-sandwich layers. The amino-terminal domains 1-3 of the protein share structural homology with the protective antigen (PA) PA14 domain and encompass a long β-pore forming loop as in the clostridial binary-toxB module. Domains 5 and 6 at the carboxyl-terminal half of Vpb4Da2 are unique as this extension is not observed in PA or any other structurally-related protein other than Vpb4 homologs. These unique Vpb4 domains adopt the topologies of carbohydrate-binding modules known to participate in receptor-recognition. Functional assessment of Vpb4Da2 suggests that domains 4-6 comprise the WCR receptor binding region and are key in conferring the observed insecticidal activity against WCR. The current structural analysis was complemented by in vitro and in vivo characterizations, including immuno-histochemistry, demonstrating that Vpb4Da2 follows a MOA that is consistent with well-characterized 3-domain Bt insecticidal proteins despite significant structural differences.
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Affiliation(s)
| | - Meiying Zheng
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Michael Aikins
- Department of Entomology, Kansas State University, Manhattan, Kansas, United States of America
| | - David Duda
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Stephen Duff
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Danqi Chen
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jun Zhang
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jason Milligan
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Christina Taylor
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | | | - Timothy Rydel
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Colton Kessenich
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Timothy Panosian
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Yong Yin
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - William Moar
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Kara Giddings
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Yoonseong Park
- Department of Entomology, Kansas State University, Manhattan, Kansas, United States of America
| | - Agoston Jerga
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jeffrey Haas
- Bayer Crop Science, Chesterfield, Missouri, United States of America
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Guo Y, Sun Y, Liao Q, Carballar-Lejarazú R, Sheng L, Wang S, Zhou J, Zhang F, Wu S. Proteolytic Activation of Bacillus thuringiensis Cry3Aa Toxin in the Red Palm Weevil (Coleoptera: Curculionidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2021; 114:2406-2411. [PMID: 34693979 DOI: 10.1093/jee/toab206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Indexed: 06/13/2023]
Abstract
The red palm weevil (RPW), Rhynchophorus ferrugineus (Oliver) is an important pest of palms that causes significant damage by boring into and feeding within palm stem tissues. Here, we studied the proteolytic process of Cry3Aa in the RPW to understand the mechanism of Cry toxicity. The bioassays showed that Cry3Aa toxin is weakly toxic to the RPW. Proteolytic activation assays indicated the Cry3Aa protein is digested into smaller fragments than the 55-kDa activated fragments under different conditions. In particular, at higher mass ratios of gut protease and Cry3Aa protein (5:1, 2:1, and 1:1, respectively), and at 36.9°C for 16 h in a solution of pH 8.6, the Cry3Aa protoxin is over-digested by the gut proteases of weevil larvae. Moreover, the zymogram analysis of the gut proteases revealed the RPW larvae harbors intestinal digestive enzymes mainly composed of serine proteases. This study describes the proteolytic activation process of Cry3Aa in the midgut of RPW larvae.
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Affiliation(s)
- Yajie Guo
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
- Laboratory of Forest Symbiology, Asian Research Center for Bioresource and Environmental Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Yunzhu Sun
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Qiliao Liao
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Rebeca Carballar-Lejarazú
- Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, CA, USA
| | - Liangjing Sheng
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shaozhen Wang
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jianshuang Zhou
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Feiping Zhang
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Songqing Wu
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
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Gonzalez-Vazquez MC, Vela-Sanchez RA, Rojas-Ruiz NE, Carabarin-Lima A. Importance of Cry Proteins in Biotechnology: Initially a Bioinsecticide, Now a Vaccine Adjuvant. Life (Basel) 2021; 11:999. [PMID: 34685371 PMCID: PMC8541582 DOI: 10.3390/life11100999] [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: 09/07/2021] [Revised: 09/19/2021] [Accepted: 09/19/2021] [Indexed: 11/21/2022] Open
Abstract
A hallmark of Bacillus thuringiensis bacteria is the formation of one or more parasporal crystal (Cry) proteins during sporulation. The toxicity of these proteins is highly specific to insect larvae, exerting lethal effects in different insect species but not in humans or other mammals. The aim of this review is to summarize previous findings on Bacillus thuringiensis, including the characteristics of the bacterium, its subsequent contribution to biotechnology as a bioinsecticide due to the presence of Cry proteins, and its potential application as an adjuvant. In several studies, Cry proteins have been administered together with specific antigens to immunize experimental animal models. The results have shown that these proteins can enhance immunogenicity by generating an adequate immune response capable of protecting the model against an experimental infectious challenge, whereas protection is decreased when the specific antigen is administered without the Cry protein. Therefore, based on previous results and the structural homology between Cry proteins, these molecules have arisen as potential adjuvants in the development of vaccines for both animals and humans. Finally, a model of the interaction of Cry proteins with different components of the immune response is proposed.
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Affiliation(s)
- Maria Cristina Gonzalez-Vazquez
- Centro de Investigaciones en Ciencias Microbiologicas, Instituto de Ciencias, Benemerita Universidad Autonoma de Puebla, Puebla 72000, PU, Mexico; (M.C.G.-V.); (N.E.R.-R.)
| | - Ruth Abril Vela-Sanchez
- Licenciatura en Biotecnología, Benemerita Universidad Autonoma de Puebla, Puebla 72000, PU, Mexico;
| | - Norma Elena Rojas-Ruiz
- Centro de Investigaciones en Ciencias Microbiologicas, Instituto de Ciencias, Benemerita Universidad Autonoma de Puebla, Puebla 72000, PU, Mexico; (M.C.G.-V.); (N.E.R.-R.)
- Licenciatura en Biotecnología, Benemerita Universidad Autonoma de Puebla, Puebla 72000, PU, Mexico;
| | - Alejandro Carabarin-Lima
- Centro de Investigaciones en Ciencias Microbiologicas, Instituto de Ciencias, Benemerita Universidad Autonoma de Puebla, Puebla 72000, PU, Mexico; (M.C.G.-V.); (N.E.R.-R.)
- Licenciatura en Biotecnología, Benemerita Universidad Autonoma de Puebla, Puebla 72000, PU, Mexico;
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10
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Tetreau G, Andreeva EA, Banneville AS, De Zitter E, Colletier JP. Can (We Make) Bacillus thuringiensis Crystallize More Than Its Toxins? Toxins (Basel) 2021; 13:toxins13070441. [PMID: 34206749 PMCID: PMC8309801 DOI: 10.3390/toxins13070441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/22/2021] [Accepted: 06/24/2021] [Indexed: 11/16/2022] Open
Abstract
The development of finely tuned and reliable crystallization processes to obtain crystalline formulations of proteins has received growing interest from different scientific fields, including toxinology and structural biology, as well as from industry, notably for biotechnological and medical applications. As a natural crystal-making bacterium, Bacillus thuringiensis (Bt) has evolved through millions of years to produce hundreds of highly structurally diverse pesticidal proteins as micrometer-sized crystals. The long-term stability of Bt protein crystals in aqueous environments and their specific and controlled dissolution are characteristics that are particularly sought after. In this article, we explore whether the crystallization machinery of Bt can be hijacked as a means to produce (micro)crystalline formulations of proteins for three different applications: (i) to develop new bioinsecticidal formulations based on rationally improved crystalline toxins, (ii) to functionalize crystals with specific characteristics for biotechnological and medical applications, and (iii) to produce microcrystals of custom proteins for structural biology. By developing the needs of these different fields to figure out if and how Bt could meet each specific requirement, we discuss the already published and/or patented attempts and provide guidelines for future investigations in some underexplored yet promising domains.
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11
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Guo Y, Carballar-Lejarazú R, Sheng L, Fang Y, Wang S, Liang G, Hu X, Wang R, Zhang F, Wu S. Identification and Characterization of Aminopeptidase-N as a Binding Protein for Cry3Aa in the Midgut of Monochamus alternatus (Coleoptera: Cerambycidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2020; 113:2259-2268. [PMID: 32623464 DOI: 10.1093/jee/toaa130] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Indexed: 06/11/2023]
Abstract
Bacillus thuringiensis Cry proteins have been widely used over the past decades for many different insect pests, which are safe for users and the environment. The coleopteran-specific Cry3Aa toxin from B. thuringiensis exhibits toxicity to the larvae of Monochamus alternatus. Receptors play a key role in the mechanisms underlying the toxic action of Cry. However, the binding receptor for Cry3Aa has yet to be identified in the midgut of M. alternatus larvae. Therefore, the aim of this study was to identify the receptor for Cry3Aa toxin in the brush border membrane vesicles (BBMVs) of M. alternatus larvae. Our results indicate that the Cry3Aa toxin binds to the BBMVs (Kd = 247 nM) of M. alternatus via a 107 kDa aminopeptidase N (APN) (Kd = 57 nM). In silico analysis of the APN protein predicted that an 18 amino acid sequence in the N-terminal acted as a signal peptide, and that the Asn residue, located at position 918 in the C-terminus is an anchored site for glycosyl phosphatidyl inositol. Further analysis showed that M. alternatus APN exhibits 75% homology to the APN from Anoplophora glabripenis. Our work, therefore, confirmed that APN, which is localized in the BBMVs in the midgut of M. alternatus larvae, acts as a binding protein for Cry3Aa toxins.
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Affiliation(s)
- Yajie Guo
- College of Forestry, Fujian Province University
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
| | | | - Liangjing Sheng
- College of Forestry, Fujian Province University
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University
| | - Yan Fang
- College of Forestry, Fujian Province University
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University
| | - Shaozhen Wang
- College of Forestry, Fujian Province University
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University
| | - Guanghong Liang
- College of Forestry, Fujian Province University
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University
| | - Xia Hu
- College of Forestry, Fujian Province University
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University
| | - Rong Wang
- College of Forestry, Fujian Province University
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University
| | - Feiping Zhang
- College of Forestry, Fujian Province University
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University
| | - Songqing Wu
- College of Forestry, Fujian Province University
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
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12
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Vílchez S. Making 3D-Cry Toxin Mutants: Much More Than a Tool of Understanding Toxins Mechanism of Action. Toxins (Basel) 2020; 12:toxins12090600. [PMID: 32948025 PMCID: PMC7551160 DOI: 10.3390/toxins12090600] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/15/2020] [Accepted: 08/20/2020] [Indexed: 12/21/2022] Open
Abstract
3D-Cry toxins, produced by the entomopathogenic bacterium Bacillus thuringiensis, have been extensively mutated in order to elucidate their elegant and complex mechanism of action necessary to kill susceptible insects. Together with the study of the resistant insects, 3D-Cry toxin mutants represent one of the pillars to understanding how these toxins exert their activity on their host. The principle is simple, if an amino acid is involved and essential in the mechanism of action, when substituted, the activity of the toxin will be diminished. However, some of the constructed 3D-Cry toxin mutants have shown an enhanced activity against their target insects compared to the parental toxins, suggesting that it is possible to produce novel versions of the natural toxins with an improved performance in the laboratory. In this report, all mutants with an enhanced activity obtained by accident in mutagenesis studies, together with all the variants obtained by rational design or by directed mutagenesis, were compiled. A description of the improved mutants was made considering their historical context and the parallel development of the protein engineering techniques that have been used to obtain them. This report demonstrates that artificial 3D-Cry toxins made in laboratories are a real alternative to natural toxins.
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Affiliation(s)
- Susana Vílchez
- Institute of Biotechnology, Department of Biochemistry and Molecular Biology I, Faculty of Science, University of Granada, 18071 Granada, Spain
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13
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Guo Y, Wang Y, O'Donoghue AJ, Jiang Z, Carballar-Lejarazú R, Liang G, Hu X, Wang R, Xu L, Guan X, Zhang F, Wu S. Engineering of multiple trypsin/chymotrypsin sites in Cry3A to enhance its activity against Monochamus alternatus Hope larvae. PEST MANAGEMENT SCIENCE 2020; 76:3117-3126. [PMID: 32323409 DOI: 10.1002/ps.5866] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/13/2020] [Accepted: 04/22/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Bacillus thuringiensis Cry3 toxins exhibit specific toxicity against several coleopteran larvae. However, owing to its low toxicity to Monochamus alternatus, Cry3A toxin is not useful for managing M. alternatus larvae. Here we assessed the proteolytic activation of Cry3Aa toxin in M. alternatus larval midgut and increased its toxicity by molecular modification. RESULTS Our results indicated that insufficient processing of Cry3Aa protoxin and non-specific enzymatic digestion of Cry3Aa toxin in the midgut of M. alternatus larvae led to low toxicity. The results of transcriptome analysis, enzymatic assay with fluorogenic substrates, and multiplex substrate profiling by mass spectrometry showed that the main digestive enzymes in M. alternatus larval midgut were trypsin-like proteases that preferentially cleaved peptides with arginine and lysine residues. Consequently, trypsin recognition sites were introduced into the Domain I of Cry3Aa protoxin in the loop regions between α-helix 3 and α-helix 4 to facilitate proteolytic activation. Multiple potential trypsin cleavage sites away from the helix sheet and functional regions in Cry3Aa proteins were also mutated to alanine to prevent non-specific enzymatic digestion. Bioassays indicated that a modified Cry3Aa-T toxin (K65A, K70A, K231A, K468A, and K596A) showed a 9.5-fold (LC50 = 12.3 μg/mL) increase in toxicity to M. alternatus larvae when compared to native Cry3Aa toxin. CONCLUSION This study highlights an effective way to increase the toxicity of Cry3Aa toxin to M. alternatus, which may be suitable for managing the resistance of transgenic plants to other pests, including some of the most important pests in agriculture. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Yajie Guo
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yafang Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
- Engineering Research Center of Molecular Diagnostics, Ministry of Education, Department of Biomedical Sciences, School of Life Sciences, Xiamen University, Xiamen, China
| | - Anthony J O'Donoghue
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
| | - Zhenze Jiang
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
| | | | - Guanghong Liang
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xia Hu
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Rong Wang
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Lei Xu
- Graduate School of Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiong Guan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Feiping Zhang
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Songqing Wu
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management in Ecological Forests, Fujian Province University, Fujian Agriculture and Forestry University, Fuzhou, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
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14
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Insecticidal Activity of Bacillus thuringiensis Proteins Against Coleopteran Pests. Toxins (Basel) 2020; 12:toxins12070430. [PMID: 32610662 PMCID: PMC7404982 DOI: 10.3390/toxins12070430] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 06/25/2020] [Accepted: 06/25/2020] [Indexed: 12/17/2022] Open
Abstract
Bacillus thuringiensis is the most successful microbial insecticide agent and its proteins have been studied for many years due to its toxicity against insects mainly belonging to the orders Lepidoptera, Diptera and Coleoptera, which are pests of agro-forestry and medical-veterinary interest. However, studies on the interactions between this bacterium and the insect species classified in the order Coleoptera are more limited when compared to other insect orders. To date, 45 Cry proteins, 2 Cyt proteins, 11 Vip proteins, and 2 Sip proteins have been reported with activity against coleopteran species. A number of these proteins have been successfully used in some insecticidal formulations and in the construction of transgenic crops to provide protection against main beetle pests. In this review, we provide an update on the activity of Bt toxins against coleopteran insects, as well as specific information about the structure and mode of action of coleopteran Bt proteins.
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15
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McDonald J, Burns A, Raybould A. Advancing ecological risk assessment on genetically engineered breeding stacks with combined insect-resistance traits. Transgenic Res 2020; 29:135-148. [PMID: 31953798 PMCID: PMC7000536 DOI: 10.1007/s11248-019-00185-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 12/19/2019] [Indexed: 11/01/2022]
Abstract
To inform the ecological risk assessment (ERA) of a transgenic crop with multiple insecticidal traits combined by conventional breeding (breeding stack), a comparative field study is customarily conducted to compare transgenic protein concentrations in a breeding stack to those in corresponding component single events used in the breeding process. This study tests the hypothesis that transgenic protein expression will not significantly increase due to stacking, such that existing margins of exposure erode to unacceptable levels. Corroboration of this hypothesis allows for the use of existing non-target organism (NTO) effects tests results, where doses were based on the estimated environmental concentrations determined for a component single event. Results from over 20 studies comparing expression profiles of insecticidal proteins produced by commercial events in various combinations of conventionally-bred stacks were examined to evaluate applying previously determined no-observed-effect concentrations (NOECs) to stack ERAs. This paper presents a large number of tests corroborating the hypothesis of no significant increase in insecticidal protein expression due to combination by conventional breeding, and much of the variation in protein expression is likely attributed to genetic and environmental factors. All transgenic protein concentrations were well within conservative margins between exposure and corresponding NOEC. This work supports the conclusion that protein expression data generated for single events and the conservative manner for setting NTO effects test concentrations allows for the transportability of existing NOECs to the ERA of conventionally-bred stacks, and that future tests of the stated hypothesis are no longer critically informative for ERA on breeding stacks.
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Affiliation(s)
- Justin McDonald
- Product Safety, Syngenta Crop Protection, LLC, Research Triangle Park, NC, USA.
| | - Andrea Burns
- Product Safety, Syngenta Crop Protection, LLC, Research Triangle Park, NC, USA
| | - Alan Raybould
- Science, Technology and Innovation Studies and Global Academy of Agriculture and Food Security, University of Edinburgh, Edinburgh, UK
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16
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Differential proteolytic activation of the Bacillus thuringiensis Cry41Aa parasporin modulates its anticancer effect. Biochem J 2019; 476:3805-3816. [PMID: 31794004 DOI: 10.1042/bcj20190732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 11/29/2019] [Accepted: 12/03/2019] [Indexed: 11/17/2022]
Abstract
Bacillus thuringiensis (Bt) is a gram positive spore forming bacterium which produces intracellular protein crystals toxic to a wide variety of insect larvae and is the most commonly used biological pesticide worldwide. More recently, Bt crystal proteins known as parasporins have been discovered, that have no known insecticidal activity but target some human cancer cells exhibiting strong cytocidal activities with different toxicity spectra and varied activity levels. Parasporin-3, also called Cry41Aa, has only been shown to exhibit cytocidal activity towards HL-60 (Human promyelocytic leukemia cells) and HepG2 (Human liver cancer cells) cell lines after being proteolytically cleaved. In order to understand this activation mechanism various mutations were made in the N-terminal region of the protein and the toxicity against both HepG2 and HL-60 cell lines was evaluated. Our results indicate that only N-terminal cleavage is required for activation and that N-terminally deleted mutants show some toxicity without the need for proteolytic activation. Furthermore, we have shown that the level of toxicity towards the two cell lines depends on the protease used to activate the toxin. Proteinase K-activated toxin was significantly more toxic towards HepG2 and HL-60 than trypsin-activated toxin. N-terminal sequencing of activated toxins showed that this difference in toxicity is associated with a difference of just two amino acids (serine and alanine at positions 59 and 60, respectively) which we hypothesize occlude a binding motif.
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17
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Rodríguez-González Á, Porteous-Álvarez AJ, Val MD, Casquero PA, Escriche B. Toxicity of five Cry proteins against the insect pest Acanthoscelides obtectus (Coleoptera: Chrisomelidae: Bruchinae). J Invertebr Pathol 2019; 169:107295. [PMID: 31783031 DOI: 10.1016/j.jip.2019.107295] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 11/22/2019] [Accepted: 11/24/2019] [Indexed: 11/29/2022]
Abstract
The beetle Acanthoscelides obtectus (Say) causes severe post-harvest losses in the common bean (Phaseolus vulgaris). Under laboratory conditions, the susceptibility of A. obtectus to five coleopteran-specific Cry toxic proteins from Bacillus thuringiensis (Cry1Ba, Cry1Ia, Cry3Aa, Cry7Ab, and Cry23/37) was evaluated. After 30 days exposure, Cry proteins demonstrated high activity against A. obtectus adults (100% mortality). Proteins showed statistical differences in toxicity parameters compared to the control treatment, but the parameters were similar among them, and indicated that the final toxic effects can be observed after the 24th day. The toxic effects on A. obtectus larvae were evaluated indirectly by allowing adults to oviposit on treated beans and recording the emergence of F1 adults. All treatments resulted in a lower rate of successful emergence compared to the control treatment, ranging from 60% (Cry23/37) to 10% (Cry1Ia) reduction in eclosion. Finally, to evaluate the ability of Cry proteins to protect the beans against A. obtectus; the number of beans infested, the number of holes in each bean and bean weight loss were determined 45 days after the treatment. The parameters showed significant bean protection by all Cry proteins analyzed compared to control treatment. Cry23/37 showed the best results, however, results for the other proteins were similar. The proteins belong to different Cry protein families, which suggest that they could be used in combination to increase plant protection without compromising resistance management. Moreover, adult emergence and bean protection results indicate differences among the proteins, which may suggest different modes of action. Our results indicate that the studied Cry proteins can be applied for the control of A. obtectus larvae and adults.
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Affiliation(s)
- Álvaro Rodríguez-González
- Grupo Universitario de Investigación en Ingeniería y Agricultura Sostenible (GUIIAS). Instituto de Medio Ambiente Recursos Naturales y Biodiversidad. Universidad de León, Avenida de Portugal 41, León 24071, Spain.
| | - Alejandra J Porteous-Álvarez
- Grupo Universitario de Investigación en Ingeniería y Agricultura Sostenible (GUIIAS). Instituto de Medio Ambiente Recursos Naturales y Biodiversidad. Universidad de León, Avenida de Portugal 41, León 24071, Spain
| | - Mario Del Val
- Grupo Universitario de Investigación en Ingeniería y Agricultura Sostenible (GUIIAS). Instituto de Medio Ambiente Recursos Naturales y Biodiversidad. Universidad de León, Avenida de Portugal 41, León 24071, Spain
| | - Pedro A Casquero
- Grupo Universitario de Investigación en Ingeniería y Agricultura Sostenible (GUIIAS). Instituto de Medio Ambiente Recursos Naturales y Biodiversidad. Universidad de León, Avenida de Portugal 41, León 24071, Spain
| | - Baltasar Escriche
- ERI de Biotecnología y Biomedicina (BIOTECMED), Departamento de Genética, Universitat de València, Burjassot 46100, Spain
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18
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Wang K, Shu C, Zhang J. Effective bacterial insecticidal proteins against coleopteran pests: A review. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2019; 102:e21558. [PMID: 31094011 DOI: 10.1002/arch.21558] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 04/02/2019] [Accepted: 04/17/2019] [Indexed: 06/09/2023]
Abstract
Coleoptera, the order of insects commonly referred to as beetles, are able to survive in various environments, and thus, comprise the largest order in the animal kingdom. Coleopterans mainly include coprophagous and phytophagous lineages, and many species of the latter lineage are serious pests. In addition to traditional chemical methods, biocontrol measures using various bacterial insecticidal proteins have also gradually been developed to control these insect pests. In this review, we summarized the possible coleopteran-pest-specific bacteria and insecticidal proteins that have been reported in the literature thus far and have provided a comprehensive overview and long-term guidance for the control of coleopteran pests in the future.
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Affiliation(s)
- Kui Wang
- College of Life Sciences, Northeast Agricultural University, Harbin, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Changlong Shu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jie Zhang
- College of Life Sciences, Northeast Agricultural University, Harbin, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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19
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Cervantes FA, Backus EA, Godfrey L, Rojas MG, Akbar W, Clark TL. Quantitative Differences in Feeding Behavior of Lygus lineolaris (Hemiptera: Miridae) on Transgenic and Nontransgenic Cotton. JOURNAL OF ECONOMIC ENTOMOLOGY 2019; 112:1920-1925. [PMID: 30915452 DOI: 10.1093/jee/toz054] [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: 06/12/2018] [Indexed: 06/09/2023]
Abstract
Lygus lineolaris (Palisot de Beauvois) is one of the most important pests on cotton in the United States. Previous research showed that transgenic cotton plants expressing the Bacillus thurigiensis (Bt) crystalline protein Cry51Aa2.834_16 (designated MON 88702) have insecticidal effects on nymphal L. lineolaris. The present study is the first to examine effects of a Bt-expressing cotton on feeding by a heteropteran like L. lineolaris. We compared stylet probing behaviors of third-instar nymphs on pin-head squares (i.e., buds <3 mm wide) of MON 88702 cotton versus nontransgenic (control) DP393 plants using AC-DC electropenetrography. Waveforms were quantified based on appearances previously characterized and correlated with adult L. lineolaris feeding behaviors; nymphal and adult waveforms had the same appearance. Generalized third-instar feeding included maceration of tissues during cell rupturing (waveform CR), tasting/testing during a waveform called transition (T), and ingestion (I); all were similar between MON 88702 and DP393 plants. However, the number of events and duration of each waveform were different between treatments. Relative to nymphs on DP393, those on MON 88702 spent more time overall in stylet probing, due to increased number of maceration events per probe and longer durations of tasting/testing, per waveform event, per probe, and per insect; yet, ingestion events were shorter and more frequent. These findings support that MON 88702 cotton plants were less palatable and/or preorally digestible to L. lineolaris nymphs than DP393, suggesting antixenosis for MON 88702. Transgenic cotton antixenosis could positively affect cotton pest management by reducing feeding of L. lineolaris nymphs and protecting crop yield.
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Affiliation(s)
- Felix A Cervantes
- USDA Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, CA
| | - Elaine A Backus
- USDA Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, CA
| | - Larry Godfrey
- Department of Entomology and Nematology, University of California, Davis, Davis, CA
| | - Maria G Rojas
- USDA Agricultural Research Service, 59 Lee Road, Stoneville, MS
| | - Waseem Akbar
- Bayer Crop Science, 800 North Lindbergh Blvd. St. Louis, MO
| | - Thomas L Clark
- Bayer Crop Science, 800 North Lindbergh Blvd. St. Louis, MO
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20
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Park Y, Hua G, Ambati S, Taylor M, Adang MJ. Binding and Synergizing Motif within Coleopteran Cadherin Enhances Cry3Bb Toxicity on the Colorado Potato Beetle and the Lesser Mealworm. Toxins (Basel) 2019; 11:toxins11070386. [PMID: 31269670 PMCID: PMC6669875 DOI: 10.3390/toxins11070386] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 06/19/2019] [Accepted: 06/24/2019] [Indexed: 12/20/2022] Open
Abstract
Cry3Bb toxin from Bacillus thuringiensis is an important insecticidal protein due to its potency against coleopteran pests, especially rootworms. Cadherin, a protein in the insect midgut epithelium, is a receptor of Cry toxins; in some insect species toxin-binding domains of cadherins-synergized Cry toxicity. Previously, we reported that the DvCad1-CR8-10 fragment of Diabrotica virgifera virgifera cadherin-like protein (GenBank Accession #EF531715) enhanced Cry3Bb toxicity to the Colorado Potato Beetle (CPB), Leptinotarsadecimlineata (L. decimlineata). We report that individual CR domains of the DvCad1-CR8-10 fragment were found to have strong binding affinities to α-chymotrypsin-treated Cry3Bb. The dissociation constant (Kd) of Cry3Bb binding to the CR8, CR9, and CR10 domain was 4.9 nM, 28.2 nM, and 4.6 nM, respectively. CR8 and CR10, but not CR9, enhanced Cry3Bb toxicity against L. decimlineata and the lesser mealworm Alphitobius diaperinus neonates. In-frame deletions of the DvCad1-CR10 open reading frame defined a high-affinity binding and synergistic site to a motif in residues I1226–D1278. A 26 amino acid peptide from the high affinity Cry3Bb-binding region of CR10 functioned as a Cry3Bb synergist against coleopteran larvae.
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Affiliation(s)
- Youngjin Park
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Gang Hua
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Suresh Ambati
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Milton Taylor
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Michael J Adang
- Department of Entomology, University of Georgia, Athens, GA 30602, USA.
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.
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21
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Zhao Z, Meihls LN, Hibbard BE, Ji T, Elsik CG, Shelby KS. Differential gene expression in response to eCry3.1Ab ingestion in an unselected and eCry3.1Ab-selected western corn rootworm (Diabrotica virgifera virgifera LeConte) population. Sci Rep 2019; 9:4896. [PMID: 30894586 PMCID: PMC6427003 DOI: 10.1038/s41598-019-41067-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 02/26/2019] [Indexed: 01/09/2023] Open
Abstract
Diabrotica virgifera virgifera LeConte, the western corn rootworm (WCR) is one of the most destructive pests in the U.S. Corn Belt. Transgenic maize lines expressing various Cry toxins from Bacillus thuringiensis have been adopted as a management strategy. However, resistance to many Bt toxins has occurred. To investigate the mechanisms of Bt resistance we carried out RNA-seq using Illumina sequencing technology on resistant, eCry3.1Ab-selected and susceptible, unselected, whole WCR neonates which fed on seedling maize with and without eCry3.1Ab for 12 and 24 hours. In a parallel experiment RNA-seq experiments were conducted when only the midgut of neonate WCR was evaluated from the same treatments. After de novo transcriptome assembly we identified differentially expressed genes (DEGs). Results from the assemblies and annotation indicate that WCR neonates from the eCry3.1Ab-selected resistant colony expressed a small number of up and down-regulated genes following Bt intoxication. In contrast, unselected susceptible WCR neonates expressed a large number of up and down-regulated transcripts in response to intoxication. Annotation and pathway analysis of DEGs between susceptible and resistant whole WCR and their midgut tissue revealed genes associated with cell membrane, immune response, detoxification, and potential Bt receptors which are likely related to eCry3.1Ab resistance. This research provides a framework to study the toxicology of Bt toxins and mechanism of resistance in WCR, an economically important coleopteran pest species.
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Affiliation(s)
- Zixiao Zhao
- Division of Plant Sciences, University of Missouri, Columbia, MO, USA
| | - Lisa N Meihls
- Division of Plant Sciences, University of Missouri, Columbia, MO, USA.,USDA-ARS, Columbia, MO, Columbia, MO, USA
| | - Bruce E Hibbard
- Division of Plant Sciences, University of Missouri, Columbia, MO, USA.,USDA-ARS, Columbia, MO, Columbia, MO, USA
| | - Tieming Ji
- Department of Statistics, University of Missouri, Columbia, MO, USA
| | - Christine G Elsik
- Division of Plant Sciences, University of Missouri, Columbia, MO, USA.,Division of Animal Sciences, University of Missouri, Columbia, MO, USA.,MU Informatics Institute, University of Missouri, Columbia, MO, USA
| | - Kent S Shelby
- Division of Plant Sciences, University of Missouri, Columbia, MO, USA. .,USDA-ARS, Columbia, MO, Columbia, MO, USA.
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22
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Hou J, Cong R, Izumi-Willcoxon M, Ali H, Zheng Y, Bermudez E, McDonald M, Nelson M, Yamamoto T. Engineering of Bacillus thuringiensis Cry Proteins to Enhance the Activity against Western Corn Rootworm. Toxins (Basel) 2019; 11:toxins11030162. [PMID: 30875860 PMCID: PMC6468356 DOI: 10.3390/toxins11030162] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 03/07/2019] [Accepted: 03/10/2019] [Indexed: 12/02/2022] Open
Abstract
A novel Bacillus thuringiensis Cry protein, Cry8Hb, active against Diabrotica virgifera virgifera (Western corn rootworm, WCRW) was discovered. Unexpectedly, the anti-rootworm activity of the Cry8Hb toxin was enhanced significantly by fusing Escherichia coli maltose binding protein (MBP) to this Cry toxin. While the exact mechanism of the activity enhancement remains indefinite, it is probable that the enhancement is a result of increased solubility of the MBP-Cry8Hb fusion in the rootworm midgut. This hypothesis was examined using a synthetic Cry3 protein called IP3-1, which was not soluble at a neutral pH like Cry8Hb and marginally active to WCRW. When IP3-1 was fused to MBP, its anti-WCRW activity was enhanced 13-fold. To further test the hypothesis, DNA shuffling was performed on IP3-1 to increase the solubility without MBP. Screening of shuffled libraries found six new IP3 variants showing very high anti-WCRW activity without MBP. Sequence and 3D structure analysis of those highly active, shuffled IP3 variants revealed several charge-altering mutations such as Lys to Glu on the putative MBP-attaching side of the IP3 molecule. It is likely that those mutations make the protein acidic to substitute the functions of MBP including enhancing the solubility of IP3 at a neutral pH.
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Affiliation(s)
- Jingtong Hou
- Corteva Agrisciences, Agriculture Division of DowDuPont, Hayward and California 94545, USA.
| | - Ruth Cong
- Corteva Agrisciences, Agriculture Division of DowDuPont, Hayward and California 94545, USA.
| | - Michi Izumi-Willcoxon
- Corteva Agrisciences, Agriculture Division of DowDuPont, Hayward and California 94545, USA.
| | - Hana Ali
- Corteva Agrisciences, Agriculture Division of DowDuPont, Hayward and California 94545, USA.
| | - Yi Zheng
- Corteva Agrisciences, Agriculture Division of DowDuPont, Hayward and California 94545, USA.
| | - Ericka Bermudez
- Corteva Agrisciences, Agriculture Division of DowDuPont, Hayward and California 94545, USA.
| | - Mark McDonald
- Corteva Agrisciences, Agriculture Division of DowDuPont, Hayward and California 94545, USA.
| | - Mark Nelson
- Corteva Agrisciences, Agriculture Division of DowDuPont, Johnston, IA 50131, USA.
| | - Takashi Yamamoto
- Corteva Agrisciences, Agriculture Division of DowDuPont, Hayward and California 94545, USA.
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23
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Abdelgaffar HM, Oppert C, Sun X, Monserrate J, Jurat-Fuentes JL. Differential heliothine susceptibility to Cry1Ac associated with gut proteolytic activity. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2019; 153:1-8. [PMID: 30744882 DOI: 10.1016/j.pestbp.2018.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 09/26/2018] [Accepted: 10/04/2018] [Indexed: 06/09/2023]
Abstract
The Cry1Ac protein is the most active insecticidal toxin from the bacterium Bacillus thuringiensis (Bt) to members of the heliothinae subfamily in Lepidoptera, which includes some of the most devastating pests of corn and cotton worldwide. However, there are wide discrepancies in susceptibility among members of this subfamily in the US. Specifically, susceptibility to Cry1Ac in Helicoverpa zea (Hz) is >100-fold lower when compared to Heliothis virescens (Hv) larvae. The biochemical properties and Cry1Ac protoxin processing activity of gut digestive fluids from larvae of Hz and Hv were compared to test their role in differential susceptibility to Cry1Ac. Comparatively lower protease activity, associated with slower Cry1Ac proteolytic processing, was detected in digestive fluids of Hz compared to Hv. Moreover, Cry1Ac toxin processed by Hz digestive fluids displayed significantly lower toxicity in vitro against cultured insect cells compared to toxin activated by Hv proteases. These data support a contributing role for gut proteases in differential susceptibility to Cry1Ac in heliothine larvae.
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Affiliation(s)
- Heba M Abdelgaffar
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37996, USA
| | - Cris Oppert
- Bayer CropScience, Morrisville, NC 27709, USA
| | - Xiaocun Sun
- Research Computing Support, Office of Information and Technology, University of Tennessee, Knoxville, TN 37996, USA
| | | | - Juan Luis Jurat-Fuentes
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37996, USA..
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24
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Yang J, Quan Y, Sivaprasath P, Shabbir MZ, Wang Z, Ferré J, He K. Insecticidal Activity and Synergistic Combinations of Ten Different Bt Toxins against Mythimna separata (Walker). Toxins (Basel) 2018; 10:E454. [PMID: 30400341 PMCID: PMC6266902 DOI: 10.3390/toxins10110454] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 10/31/2018] [Accepted: 11/01/2018] [Indexed: 11/23/2022] Open
Abstract
The oriental armyworm (OAW), Mythimna separata (Walker), is a destructive pest of agricultural crops in Asia and Australia. Commercialized Bt crops have performed very well against their target pests; however, very few studies have been done on the susceptibility of OAW to Bt toxins in either sprays or expressed in Bt crops. In this work, we evaluated the toxicities of Cry1Ab, Cry1Ac, Cry1Ah, Cry1Fa, Cry2Aa, Cry2Ab, Cry1Ie, Vip3Aa19, Vip3Aa16, and Vip3Ca against OAW neonate larvae, as well as the interaction between Cry and Vip toxins. The results from bioassays revealed that LC50 (lethal concentration for 50% mortality) values ranged from 1.6 to 78.6 μg/g (toxin/diet) for those toxins. Among them, Vip3 proteins, along with Cry1A proteins and Cry2Aa, were the ones with the highest potency, with LC50 values ranging from 1.6 to 7.4 μg/g. Synergism between Cry and Vip toxins was observed, being high in the combination of Vip3Aa16 with Cry1 toxins, with synergetic factors ranging from 2.2 to 9.2. The Vip3Ca toxin did not show any synergistic effect with any of the toxins tested. These results can help in designing new combinations of pyramiding genes in Bt crops, as well as in recombinant bacteria, for the control of OAW as well as for resistance management programs.
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Affiliation(s)
- Jing Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2, West Yuanmingyuan Road, Beijing 100193, China.
| | - Yudong Quan
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain.
| | - Prabu Sivaprasath
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2, West Yuanmingyuan Road, Beijing 100193, China.
| | - Muhammad Zeeshan Shabbir
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2, West Yuanmingyuan Road, Beijing 100193, China.
| | - Zhenying Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2, West Yuanmingyuan Road, Beijing 100193, China.
| | - Juan Ferré
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain.
| | - Kanglai He
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, No. 2, West Yuanmingyuan Road, Beijing 100193, China.
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25
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Geisert RW, Cheruiyot DJ, Hibbard BE, Shapiro-Ilan DI, Shelby KS, Coudron TA. Comparative Assessment of Four Steinernematidae and Three Heterorhabditidae Species for Infectivity of Larval Diabrotica Virgifera Virgifera. JOURNAL OF ECONOMIC ENTOMOLOGY 2018; 111:542-548. [PMID: 29365135 DOI: 10.1093/jee/tox372] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Larval Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) were exposed to seven different entomopathogenic nematode species to test their potential infectivity in a laboratory setting. Known D. virgifera-infecting nematode species Heterorhabditis bacteriophora Poinar, Heterorhabditis megidis Poinar, Jackson & Klein, Steinernema feltiae Filipjev, and Steinernema carpocapsae Weiser were tested in a concerted experiment alongside Steinernema diaprepesi Nguyen & Duncan, Steinernema riobrave Cabanillas, Poinar & Raulston, and a Missouri wild-type H. bacteriophora which have not been previously tested on D. virgifera. The species S. rarum Doucet was tested separately for D. virgifera infectivity. Third-instar D. virgifera were exposed to either 60 or 120 nematodes per larva for 6 d. Following exposure, mortality was recorded and larvae were examined to determine the presence of active nematode infections. Results indicated a significantly higher proportion of larvae with active infections from the Heterorhabditidae species and S. diaprepesi than the other Steinernematidae species for both exposure rates; mortality data indicated a similar trend. Steinernema rarum showed almost no infectivity in laboratory experiments.
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Affiliation(s)
- Ryan W Geisert
- Biological Control of Insects Research Laboratory, USDA-Agricultural Research Service, Columbia, MO
| | - Dorothy J Cheruiyot
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA
| | - Bruce E Hibbard
- Plant Genetics Research Unit, USDA-Agricultural Research Service, Columbia, MO
| | - David I Shapiro-Ilan
- Southeastern Fruit and Tree Nut Research Laboratory, USDA-Agricultural Research Service, Byron, GA
| | - Kent S Shelby
- Biological Control of Insects Research Laboratory, USDA-Agricultural Research Service, Columbia, MO
| | - Thomas A Coudron
- Biological Control of Insects Research Laboratory, USDA-Agricultural Research Service, Columbia, MO
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26
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Wei J, O'Rear J, Schellenberger U, Rosen BA, Park Y, McDonald MJ, Zhu G, Xie W, Kassa A, Procyk L, Perez Ortega C, Zhao J, Yalpani N, Crane VC, Diehn SH, Sandahl GA, Nelson ME, Lu AL, Wu G, Liu L. A selective insecticidal protein from Pseudomonas mosselii for corn rootworm control. PLANT BIOTECHNOLOGY JOURNAL 2018; 16:649-659. [PMID: 28796437 PMCID: PMC5787824 DOI: 10.1111/pbi.12806] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 07/22/2017] [Accepted: 08/04/2017] [Indexed: 06/07/2023]
Abstract
The coleopteran insect western corn rootworm (WCR, Diabrotica virgifera virgifera) is an economically important pest in North America and Europe. Transgenic corn plants producing Bacillus thuringiensis (Bt) insecticidal proteins have been useful against this devastating pest, but evolution of resistance has reduced their efficacy. Here, we report the discovery of a novel insecticidal protein, PIP-47Aa, from an isolate of Pseudomonas mosselii. PIP-47Aa sequence shows no shared motifs, domains or signatures with other known proteins. Recombinant PIP-47Aa kills WCR, two other corn rootworm pests (Diabrotica barberi and Diabrotica undecimpunctata howardi) and two other beetle species (Diabrotica speciosa and Phyllotreta cruciferae), but it was not toxic to the spotted lady beetle (Coleomegilla maculata) or seven species of Lepidoptera and Hemiptera. Transgenic corn plants expressing PIP-47Aa show significant protection from root damage by WCR. PIP-47Aa kills a WCR strain resistant to mCry3A and does not share rootworm midgut binding sites with mCry3A or AfIP-1A/1B from Alcaligenes that acts like Cry34Ab1/Cry35Ab1. Our results indicate that PIP-47Aa is a novel insecticidal protein for controlling the corn rootworm pests.
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Affiliation(s)
| | | | - Ute Schellenberger
- DuPont PioneerHaywardCAUSA
- Present address:
TeneoBio Inc.1490 O'Brien DriveMenlo ParkCA94025USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Lu Liu
- DuPont PioneerHaywardCAUSA
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27
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Shah JV, Yadav R, Ingle SS. Engineered Cry1Ac-Cry9Aa hybrid Bacillus thuringiensis delta-endotoxin with improved insecticidal activity against Helicoverpa armigera. Arch Microbiol 2017; 199:1069-1075. [PMID: 28685236 DOI: 10.1007/s00203-017-1407-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 04/14/2017] [Accepted: 06/28/2017] [Indexed: 10/19/2022]
Abstract
Recombinant Bt construct was prepared by exchange of pore forming domain I with cry1Ac to cry9Aa gene by overlap extension PCR (OE-PCR) technique. Construction of cry1Ac-cry9Aa was accomplished by six base pair homology at 3' ends of PCR products of domain I of cry1Ac and domain II and III of cry9Aa. The recombinant toxin was also modified by deletion of N-terminal alpha helix-1 of recombinant toxin. Both Cry toxins were expressed in E. coli BL21(DE3) plysS and purified by His-tag purification. Upon insect bioassay analysis against devastating crop pest Helicoverpa armigera, toxicity of recombinant toxin was found around fivefold higher than native Cry1Ac while alpha helix-1 deleted N-terminal modified toxin did not resulted in significant increase in toxicity. The recombinant Cry toxins such as Cry1Ac-Cry9Aa and Cry1Ac-Cry9AaMod may be used for insect pest control.
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Affiliation(s)
- Jigar V Shah
- Ground Floor Lab, Department of Microbiology and Biotechnology Centre, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, India
| | - Rakeshkumar Yadav
- Ground Floor Lab, Department of Microbiology and Biotechnology Centre, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, India
| | - Sanjay S Ingle
- Ground Floor Lab, Department of Microbiology and Biotechnology Centre, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, India.
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28
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Cry3Bb1-Resistant Western Corn Rootworm, Diabrotica virgifera virgifera (LeConte) Does Not Exhibit Cross-Resistance to DvSnf7 dsRNA. PLoS One 2017; 12:e0169175. [PMID: 28060922 PMCID: PMC5217956 DOI: 10.1371/journal.pone.0169175] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 12/13/2016] [Indexed: 11/28/2022] Open
Abstract
Background and Methodology There is a continuing need to express new insect control compounds in transgenic maize against western corn rootworm, Diabrotica virgifera virgifera (LeConte) (WCR). In this study three experiments were conducted to determine cross-resistance between the new insecticidal DvSnf7 dsRNA, and Bacillus thuringiensis (Bt) Cry3Bb1; used to control WCR since 2003, with field-evolved resistance being reported. Laboratory susceptible and Cry3Bb1-resistant WCR were evaluated against DvSnf7 dsRNA in larval diet-incorporation bioassays. Additionally, the susceptibility of seven field and one field-derived WCR populations to DvSnf7 (and Cry3Bb1) was assessed in larval diet-overlay bioassays. Finally, beetle emergence of laboratory susceptible and Cry3Bb1-resistant WCR was evaluated with maize plants in the greenhouse expressing Cry3Bb1, Cry34Ab1/Cry35Ab1, or DvSnf7 dsRNA singly, or in combination. Principal Findings and Conclusions The Cry3Bb1-resistant colony had slight but significantly (2.7-fold; P<0.05) decreased susceptibility to DvSnf7 compared to the susceptible colony, but when repeated using a field-derived WCR population selected for reduced Cry3Bb1 susceptibility, there was no significant difference (P<0.05) in DvSnf7 susceptibility compared to that same susceptible population. Additionally, this 2.7-fold difference in susceptibility falls within the range of DvSnf7 susceptibility among the seven field populations tested. Additionally, there was no correlation between susceptibility to DvSnf7 and Cry3Bb1 for all populations evaluated. In greenhouse studies, there were no significant differences (P<0.05) between beetle emergence of susceptible and Cry3Bb1-resistant colonies on DvSnf7 and Cry34Ab1/Cry35Ab1, and between DvSnf7 and MON 87411 (DvSnf7 + Cry3Bb1) for the Cry3Bb1-resistant colony. These results demonstrate no cross-resistance between DvSnf7 and Cry3Bb1 against WCR. Therefore, pyramiding DvSnf7 with Bt proteins such as Cry3Bb1 and Cry34Ab1/Cry35Ab1 will provide a valuable IRM tool against WCR that will increase the durability of these Bt proteins. These results also illustrate the importance of using appropriate bioassay methods when characterizing field-evolved resistant WCR populations.
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29
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Jurat-Fuentes JL, Crickmore N. Specificity determinants for Cry insecticidal proteins: Insights from their mode of action. J Invertebr Pathol 2017; 142:5-10. [DOI: 10.1016/j.jip.2016.07.018] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 06/02/2016] [Accepted: 07/28/2016] [Indexed: 12/17/2022]
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30
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Graser G, Walters FS, Burns A, Sauve A, Raybould A. A General Approach to Test for Interaction Among Mixtures of Insecticidal Proteins Which Target Different Orders of Insect Pests. JOURNAL OF INSECT SCIENCE (ONLINE) 2017; 17:3065810. [PMID: 28355479 PMCID: PMC5416900 DOI: 10.1093/jisesa/iex003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Indexed: 05/31/2023]
Abstract
A shift toward transgenic crops which produce combinations of insecticidal proteins has increased the interest (Syngenta Seeds, Inc., Minnetonka, MN) in studying the potential for interactions amongst those proteins. We present a general testing method which accommodates proteins with nonoverlapping spectrums of activity. Our sequential testing approach first investigates groups of the proteins with overlapping activity; e.g., proteins active against Lepidoptera or Coleoptera, respectively. The Colby method is used to test for interactions within each respective group. Subsequently, the mixture of proteins within each group is regarded as a single entity and tests for interactions between the groups (when combined) is conducted using analysis of variance. We illustrate the method using Cry1Ab, Vip3Aa20, and Cry1F (a mixture of proteins active against Lepidoptera), and mCry3A and eCry3.1Ab (a mixture of proteins active against Coleoptera). These insecticidal proteins are produced by Bt11 × MIR162 × TC1507 × MIR604 × 5307 maize. We detected no interactions between Cry1Ab, Vip3Aa20, and Cry1F in tests using larvae of two different lepidopteran species, and possible slight antagonism between mCry3A and eCry3.1Ab with a coleopteran test species. We detected no effect of (eCry3.1Ab + mCry3A) on the potency of (Cry1Ab + Vip3Aa20 + Cry1F) to lepidopteran larvae, and no effect of (Cry1Ab + Vip3Aa20 + Cry1F) on the potency of (mCry3A + eCry3.1Ab) to coleopteran larvae. We discuss implications of these results for characterization of Bt11 × MIR162 × TC1507 × MIR604 × 5307 maize, and the value of the method for characterizing other transgenic crops that produce several insecticidal proteins.
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Affiliation(s)
- Gerson Graser
- Syngenta Crop Protection, Product Safety, LLC, PO Box 12257, 9 Davis Drive, Durham, NC 27709, USA
| | - Frederick S. Walters
- Syngenta Crop Protection, Product Safety, LLC, PO Box 12257, 9 Davis Drive, Durham, NC 27709, USA
| | - Andrea Burns
- Syngenta Crop Protection, Product Safety, LLC, PO Box 12257, 9 Davis Drive, Durham, NC 27709, USA
| | - Alaina Sauve
- Syngenta Crop Protection, Product Safety, LLC, PO Box 12257, 9 Davis Drive, Durham, NC 27709, USA
| | - Alan Raybould
- Syngenta Crop Protection AG, Regulatory Affairs, Schwarzwaldallee 215, Basel, CH-4058, Switzerland
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Hernández-Martínez P, Vera-Velasco NM, Escriche B. Unshared binding sites for Bacillus thuringiensis Cry3Aa and Cry3Ca proteins in the weevil Cylas puncticollis (Brentidae). Toxicon 2016; 122:50-53. [PMID: 27662801 PMCID: PMC5090047 DOI: 10.1016/j.toxicon.2016.09.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 09/16/2016] [Accepted: 09/17/2016] [Indexed: 11/01/2022]
Abstract
Bacillus thuringiensis Cry3Aa and Cry3Ca proteins have been reported to be toxic against the African sweetpotato pest Cylas puncticollis. In the present work, the binding sites of these proteins in C. puncticollis brush border vesicles suggest the occurrence of different binding sites, but only one of them is shared. Our results suggest that pest resistance mediated by alteration of the shared Cry-receptor binding site might not render both Cry proteins ineffective. N-terminal sequence of Cry3C activated by trypsin or chymotrypsin was identified at 159 and 153 positions, respectively. Cry3Aa and Cry3Ca proteins bound specifically to C. puncticollis BBMV. Cry3Aa and Cry3Ca proteins do not completely compete for the same binding sites.
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32
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Geisert RW, Hibbard BE. Evaluation of Potential Fitness Costs Associated With eCry3.1Ab Resistance in Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2016; 109:1853-1858. [PMID: 27151470 DOI: 10.1093/jee/tow095] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 04/10/2016] [Indexed: 06/05/2023]
Abstract
Both an eCry3.1Ab-selected and paired control western corn rootworm, Diabrotica virgifera virgifera LeConte, colony were tested for adult longevity, egg oviposition, egg viability, and larval development in order to evaluate the potential fitness costs associated with eCry3.1Ab resistance. Adult longevity experiments were conducted by pairing virgin males and females together in plastic boxes supplied with food, water, and ovipositional medium and observed for survival time. Eggs were also collected from the ovipositional medium once a week to determine average egg oviposition and egg viability. Larval development time experiments were conducted by infesting seedling assays with 25 neonate larvae and recording larval recovery after several days. Adult longevity, average egg oviposition, and larval development time results indicated a lack of fitness costs associated with eCry3.1Ab resistance in the western corn rootworm. Results of egg viability indicated a fitness advantage for the eCry3.1Ab-selected colony with a significantly higher egg hatch than the control.
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Affiliation(s)
- Ryan W Geisert
- USDA-ARS, 1503 S. Providence, Research PK, Columbia, MO 65211 ,
| | - Bruce E Hibbard
- USDA-ARS, 205 Curtis Hall, University of Missouri, Columbia, MO 65211
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33
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Gowda A, Rydel TJ, Wollacott AM, Brown RS, Akbar W, Clark TL, Flasinski S, Nageotte JR, Read AC, Shi X, Werner BJ, Pleau MJ, Baum JA. A transgenic approach for controlling Lygus in cotton. Nat Commun 2016; 7:12213. [PMID: 27426014 PMCID: PMC4960306 DOI: 10.1038/ncomms12213] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 06/13/2016] [Indexed: 01/22/2023] Open
Abstract
Lygus species of plant-feeding insects have emerged as economically important pests of cotton in the United States. These species are not controlled by commercial Bacillus thuringiensis (Bt) cotton varieties resulting in economic losses and increased application of insecticide. Previously, a Bt crystal protein (Cry51Aa2) was reported with insecticidal activity against Lygus spp. However, transgenic cotton plants expressing this protein did not exhibit effective protection from Lygus feeding damage. Here we employ various optimization strategies, informed in part by protein crystallography and modelling, to identify limited amino-acid substitutions in Cry51Aa2 that increase insecticidal activity towards Lygus spp. by >200-fold. Transgenic cotton expressing the variant protein, Cry51Aa2.834_16, reduce populations of Lygus spp. up to 30-fold in whole-plant caged field trials. One transgenic event, designated MON88702, has been selected for further development of cotton varieties that could potentially reduce or eliminate insecticide application for control of Lygus and the associated environmental impacts. Plant-feeding insects of the Lygus genus have emerged as a major pest effecting cotton crops in the USA. Here the authors optimize the insecticidal activity of a Bacillus thuringiensis crystal protein and produce transgenic plants that are resistant to feeding damage by Lygus species.
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Affiliation(s)
| | | | | | | | - Waseem Akbar
- Monsanto Company, Chesterfield, Missouri 63017, USA
| | | | | | | | | | - Xiaohong Shi
- Monsanto Company, Chesterfield, Missouri 63017, USA
| | | | | | - James A Baum
- Monsanto Company, Chesterfield, Missouri 63017, USA
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Jakka SRK, Shrestha RB, Gassmann AJ. Broad-spectrum resistance to Bacillus thuringiensis toxins by western corn rootworm (Diabrotica virgifera virgifera). Sci Rep 2016; 6:27860. [PMID: 27297953 PMCID: PMC4906537 DOI: 10.1038/srep27860] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 05/25/2016] [Indexed: 12/27/2022] Open
Abstract
The evolution of resistance and cross-resistance threaten the sustainability of genetically engineered crops that produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt). Western corn rootworm, Diabrotica virgifera virgifera LeConte, is a serious pest of maize and has been managed with Bt maize since 2003. We conducted laboratory bioassays with maize hybrids producing Bt toxins Cry3Bb1, mCry3A, eCry3.1Ab, and Cry34/35Ab1, which represent all commercialized Bt toxins for management of western corn rootworm. We tested populations from fields where severe injury to Cry3Bb1 maize was observed, and populations that had never been exposed to Bt maize. Consistent with past studies, bioassays indicated that field populations were resistant to Cry3Bb1 maize and mCry3A maize, and that cross-resistance was present between these two types of Bt maize. Additionally, bioassays revealed resistance to eCry3.1Ab maize and cross-resistance among Cry3Bb1, mCry3A and eCry3.1Ab. However, no resistance or cross-resistance was detected for Cry34/35Ab1 maize. This broad-spectrum resistance illustrates the potential for insect pests to develop resistance rapidly to multiple Bt toxins when structural similarities are present among toxins, and raises concerns about the long-term durability of Bt crops for management of some insect pests.
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Affiliation(s)
- Siva R. K. Jakka
- Department of Entomology, Iowa State University, Ames, IA 50011, USA.
| | - Ram B. Shrestha
- Department of Entomology, Iowa State University, Ames, IA 50011, USA.
| | - Aaron J. Gassmann
- Department of Entomology, Iowa State University, Ames, IA 50011, USA.
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Broad-spectrum resistance to Bacillus thuringiensis toxins by western corn rootworm (Diabrotica virgifera virgifera). Sci Rep 2016. [PMID: 27297953 DOI: 10.1038/srep27860.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The evolution of resistance and cross-resistance threaten the sustainability of genetically engineered crops that produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt). Western corn rootworm, Diabrotica virgifera virgifera LeConte, is a serious pest of maize and has been managed with Bt maize since 2003. We conducted laboratory bioassays with maize hybrids producing Bt toxins Cry3Bb1, mCry3A, eCry3.1Ab, and Cry34/35Ab1, which represent all commercialized Bt toxins for management of western corn rootworm. We tested populations from fields where severe injury to Cry3Bb1 maize was observed, and populations that had never been exposed to Bt maize. Consistent with past studies, bioassays indicated that field populations were resistant to Cry3Bb1 maize and mCry3A maize, and that cross-resistance was present between these two types of Bt maize. Additionally, bioassays revealed resistance to eCry3.1Ab maize and cross-resistance among Cry3Bb1, mCry3A and eCry3.1Ab. However, no resistance or cross-resistance was detected for Cry34/35Ab1 maize. This broad-spectrum resistance illustrates the potential for insect pests to develop resistance rapidly to multiple Bt toxins when structural similarities are present among toxins, and raises concerns about the long-term durability of Bt crops for management of some insect pests.
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36
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Rausch MA, Chougule NP, Deist BR, Bonning BC. Modification of Cry4Aa toward Improved Toxin Processing in the Gut of the Pea Aphid, Acyrthosiphon pisum. PLoS One 2016; 11:e0155466. [PMID: 27171411 PMCID: PMC4865192 DOI: 10.1371/journal.pone.0155466] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 04/30/2016] [Indexed: 11/19/2022] Open
Abstract
Aphids are sap-sucking insects (order: Hemiptera) that cause extensive damage to a wide range of agricultural crops. Our goal was to optimize a naturally occurring insecticidal crystalline (Cry) toxins produced by the soil-dwelling bacterium Bacillus thuringiensis for use against the pea aphid, Acyrthosiphon pisum. On the basis that activation of the Cry4Aa toxin is a rate-limiting factor contributing to the relatively low aphicidal activity of this toxin, we introduced cathepsin L and cathepsin B cleavage sites into Cry4Aa for rapid activation in the aphid gut environment. Incubation of modified Cry4Aa and aphid proteases in vitro demonstrated enhanced processing of the toxin into the active form for some of the modified constructs relative to non-modified Cry4Aa. Aphids fed artificial diet with toxin at a final concentration of 125 μg/ml showed enhanced mortality after two days for one of the four modified constructs. Although only modest toxin improvement was achieved by use of this strategy, such specific toxin modifications designed to overcome factors that limit aphid toxicity could be applied toward managing aphid populations via transgenic plant resistance.
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Affiliation(s)
- Michael A. Rausch
- Department of Entomology, Iowa State University, Ames, Iowa, United States of America
| | - Nanasaheb P. Chougule
- Department of Entomology, Iowa State University, Ames, Iowa, United States of America
| | - Benjamin R. Deist
- Department of Entomology, Iowa State University, Ames, Iowa, United States of America
| | - Bryony C. Bonning
- Department of Entomology, Iowa State University, Ames, Iowa, United States of America
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Geisert RW, Ellersieck MR, Hibbard BE. Tolerance of eCry3.1Ab in Reciprocal Cross Offspring of eCry3.1Ab-Selected and Control Colonies of Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2016; 109:815-820. [PMID: 26628501 DOI: 10.1093/jee/tov335] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Two new insect colonies were created by separating virgin western corn rootworm, Diabrotica virgifera virgifera LeConte, males and females from both a selected laboratory colony that was being reared on eCry3.1Ab-expressing corn (Zea mays L.) and a control colony reared on its near-isoline corn. Females from the selected colony were paired with males of the control colony and vice versa to create both a selected female by control male colony (Sel♀) and control female by selected male colony (Con♀). Both colonies along with their parental colonies (eCry3.1Ab-selected and control) were evaluated on eCry3.1Ab-expressing corn and its near-isoline in seedling assays. Larvae from each colony were also used in diet toxicity experiments in order to determine the LC50 and EC50 values for the eCry3.1Ab toxin for each. Statistical analysis of seedling assay experiments did not indicate any significant colony×corn interaction but did show a significant main effect of corn type for both larval recovery and larval head capsule widths. Results from the diet toxicity assays showed the control colony to have a significantly lower LC50 value than the selected and cross colonies and a significantly lower EC50 than the selected and Con♀ colonies. Calculations of dominance values (h) of eCry3.1Ab resistance traits from seedling assays indicated that the two reciprocal cross colonies have a dominance value (h) of ∼1, suggesting dominance of the eCry3.1Ab resistance trait.
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38
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Zhao JZ, Oneal MA, Richtman NM, Thompson SD, Cowart MC, Nelson ME, Pan Z, Alves AP, Yamamoto T. mCry3A-Selected Western Corn Rootworm (Coleoptera: Chrysomelidae) Colony Exhibits High Resistance and Has Reduced Binding of mCry3A to Midgut Tissue. JOURNAL OF ECONOMIC ENTOMOLOGY 2016; 109:1369-1377. [PMID: 27016600 DOI: 10.1093/jee/tow049] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 02/25/2016] [Indexed: 06/05/2023]
Abstract
Several Bt maize events expressing various insecticidal Cry protein genes have been commercialized for management of western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae). We used high efficacy (>99.7%) experimental maize events that express mCry3A for selections under laboratory conditions to develop a western corn rootworm colony resistant to mCry3A at higher levels than published results. The resistance ratio (RR) to mCry3A was >97-fold based on LC 50 values in diet-based bioassays after six generations of selections when compared to that of an unselected Control colony. Using a sublethal seedling assay (SSA) method, we confirmed that the colony had no cross-resistance to maize event DAS-59122-7, which expresses Cry34/35Ab. Reciprocal crosses between the mCry3A-resistant colony and the susceptible colony were performed to test the inheritance of resistance. Larval survival and development evaluated by the SSA method indicated that resistance to mCry3A was inherited autosomally and was incompletely recessive (h = 0.23-0.25). Specific binding of mCry3A to brush border membrane vesicles of midgut tissue revealed reduced binding in the resistant colony when compared to binding in the susceptible colony. This is the first report where resistance in western corn rootworm has been shown to involve reduced binding of a Cry3-class protein in midgut tissue.
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39
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Wu S, Zhu X, Liu Z, Shao E, Rebeca CL, Guo Y, Xiong Y, Mou Y, Xu R, Hu X, Liang G, Zou S, Guan X, Zhang F. Identification of Genes Relevant to Pesticides and Biology from Global Transcriptome Data of Monochamus alternatus Hope (Coleoptera: Cerambycidae) Larvae. PLoS One 2016; 11:e0147855. [PMID: 26815657 PMCID: PMC4729689 DOI: 10.1371/journal.pone.0147855] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 01/08/2016] [Indexed: 12/13/2022] Open
Abstract
Monochamus alternatus Hope is the main vector in China of the Pine Wilt Disease caused by the pine wood nematode Bursaphelenchus xylophilus. Although chemical control is traditionally used to prevent pine wilt disease, new strategies based in biological control are promising ways for the management of the disease. However, there is no deep sequence analysis of Monochamus alternatus Hope that describes the transcriptome and no information is available about gene function of this insect vector. We used next generation sequencing technology to sequence the whole fourth instar larva transcriptome of Monochamus alternatus Hope and successfully built a Monochamus alternatus Hope transcriptome database. In total, 105,612 unigenes were assigned for Gene Ontology (GO) terms, information for 16,730 classified unigenes was obtained in the Clusters of Orthologous Groups (COGs) database, and 13,024 unigenes matched with 224 predicted pathways in the Kyoto Encyclopedia of Genes and Genome (KEGG). In addition, genes related to putative insecticide resistance-related genes, RNAi, the Bt receptor, intestinal digestive enzymes, possible future insect control targets and immune-related molecules are described. This study provides valuable basic information that can be used as a gateway to develop new molecular tools for Monochamus alternatus Hope control strategies.
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Affiliation(s)
- Songqing Wu
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
- Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
| | - Xiaoli Zhu
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
- Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
| | - Zhaoxia Liu
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
- Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
| | - Ensi Shao
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
- Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
| | - Carballar-Lejarazú Rebeca
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, CA, 92697, United States of America
| | - Yajie Guo
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
| | - Yueting Xiong
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
| | - Yani Mou
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
| | - Runxue Xu
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
| | - Xia Hu
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
| | - Guanghong Liang
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
| | - Shuangquan Zou
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
| | - Xiong Guan
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
- Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
- * E-mail: (FPZ); (XG)
| | - Feiping Zhang
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, 350002, People’s Republic of China
- * E-mail: (FPZ); (XG)
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40
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Lombardo L, Coppola G, Zelasco S. New Technologies for Insect-Resistant and Herbicide-Tolerant Plants. Trends Biotechnol 2016; 34:49-57. [DOI: 10.1016/j.tibtech.2015.10.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/21/2015] [Accepted: 10/22/2015] [Indexed: 12/17/2022]
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41
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Frank DL, Kurtz R, Tinsley NA, Gassmann AJ, Meinke LJ, Moellenbeck D, Gray ME, Bledsoe LW, Krupke CH, Estes RE, Weber P, Hibbard BE. Effect of Seed Blends and Soil-Insecticide on Western and Northern Corn Rootworm Emergence from mCry3A+eCry3.1Ab Bt Maize. JOURNAL OF ECONOMIC ENTOMOLOGY 2015; 108:1260-1270. [PMID: 26470254 DOI: 10.1093/jee/tov081] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 03/13/2015] [Indexed: 06/05/2023]
Abstract
Seed blends containing various ratios of transgenic Bt maize (Zea mays L.) expressing the mCry3A+eCry3.1Ab proteins and non-Bt maize (near-isoline maize) were deployed alone and in combination with a soil applied pyrethroid insecticide (Force CS) to evaluate the emergence of the western corn rootworm, Diabrotica virgifera virgifera LeConte, in a total of nine field environments across the Midwestern United States in 2010 and 2011. Northern corn rootworm, Diabrotica barberi Smith & Lawrence emergence was also evaluated in four of these environments. Both western and northern corn rootworm beetle emergence from all Bt treatments was significantly reduced when compared with beetle emergence from near-isoline treatments. Averaged across all environments, western corn rootworm beetle emergence from 95:5, 90:10, and 80:20 seed blend ratios of mCry3A+eCry3.1Ab: near-isoline were 2.6-, 4.2-, and 6.7-fold greater than that from the 100:0 ratio treatment. Northern corn rootworm emergence from the same seed blend treatments resulted in 2.8-, 3.2-, and 4.2-fold more beetles than from the 100:0 treatment. The addition of Force CS (tefluthrin) significantly reduced western corn rootworm beetle emergence for each of the three treatments to which it was applied. Force CS also significantly delayed the number of days to 50% beetle emergence in western corn rootworms. Time to 50% beetle emergence in the 100% mCry3A+eCry3.1Ab treatment with Force CS was delayed 13.7 d when compared with western corn rootworm beetle emergence on near-isoline corn. These data are discussed in terms of rootworm resistance management.
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Affiliation(s)
- Daniel L Frank
- USDA-ARS, Plant Genetics Research Unit, 205 Curtis Hall, University of Missouri, Columbia, MO 65211, USA Present address: Extension Service, Agriculture and Natural Resources Unit, West Virginia University, Morgantown, WV 26506, USA
| | - Ryan Kurtz
- Syngenta Biotechnology, Inc., 3054 E. Cornwallis Rd., Research Triangle Park, NC 27709, USA Present address: Cotton Incorporated, 6399 Weston Pkwy, Cary, NC 27513, USA
| | - Nicholas A Tinsley
- Department of Crop Sciences, University of Illinois, Urbana, IL 61801, USA
| | - Aaron J Gassmann
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
| | - Lance J Meinke
- Department of Entomology, University of Nebraska, Lincoln, NE 68583, USA
| | - Daniel Moellenbeck
- DM Crop Research Group, Inc., 700 North 3rd St., P.O. Box 53, Polk City, IA 50226, USA
| | - Michael E Gray
- Department of Crop Sciences, University of Illinois, Urbana, IL 61801, USA
| | - Larry W Bledsoe
- Department of Entomology, Purdue University, West Lafayette, IN 47907, USA
| | - Christian H Krupke
- Department of Entomology, Purdue University, West Lafayette, IN 47907, USA
| | - Ronald E Estes
- Department of Crop Sciences, University of Illinois, Urbana, IL 61801, USA
| | - Patrick Weber
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
| | - Bruce E Hibbard
- USDA-ARS, Plant Genetics Research Unit, 205 Curtis Hall, University of Missouri, Columbia, MO 65211, USA
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42
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Bt toxin modification for enhanced efficacy. Toxins (Basel) 2014; 6:3005-27. [PMID: 25340556 PMCID: PMC4210883 DOI: 10.3390/toxins6103005] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 09/28/2014] [Accepted: 09/29/2014] [Indexed: 11/23/2022] Open
Abstract
Insect-specific toxins derived from Bacillus thuringiensis (Bt) provide a valuable resource for pest suppression. Here we review the different strategies that have been employed to enhance toxicity against specific target species including those that have evolved resistance to Bt, or to modify the host range of Bt crystal (Cry) and cytolytic (Cyt) toxins. These strategies include toxin truncation, modification of protease cleavage sites, domain swapping, site-directed mutagenesis, peptide addition, and phage display screens for mutated toxins with enhanced activity. Toxin optimization provides a useful approach to extend the utility of these proteins for suppression of pests that exhibit low susceptibility to native Bt toxins, and to overcome field resistance.
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43
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Shared binding sites for the Bacillus thuringiensis proteins Cry3Bb, Cry3Ca, and Cry7Aa in the African sweet potato pest Cylas puncticollis (Brentidae). Appl Environ Microbiol 2014; 80:7545-50. [PMID: 25261517 DOI: 10.1128/aem.02514-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Bacillus thuringiensis Cry3Bb, Cry3Ca, and Cry7Aa have been reported to be toxic against larvae of the genus Cylas, which are important pests of sweet potato worldwide and particularly in sub-Saharan Africa. However, relatively little is known about the processing and binding interactions of these coleopteran-specific Cry proteins. The aim of the present study was to determine whether Cry3Bb, Cry3Ca, and Cry7Aa proteins have shared binding sites in Cylas puncticollis to orient the pest resistance strategy by genetic transformation. Interestingly, processing of the 129-kDa Cry7Aa protoxin using commercial trypsin or chymotrypsin rendered two fragments of about 70 kDa and 65 kDa. N-terminal sequencing of the trypsin-activated Cry7Aa fragments revealed that processing occurs at Glu(47) for the 70-kDa form or Ile(88) for the 65-kDa form. Homologous binding assays showed specific binding of the two Cry3 proteins and the 65-kDa Cry7Aa fragment to brush border membrane vesicles (BBMV) from C. puncticollis larvae. The 70-kDa fragment did not bind to BBMV. Heterologous-competition assays showed that Cry3Bb, Cry3Ca, and Cry7Aa (65-kDa fragment) competed for the same binding sites. Hence, our results suggest that pest resistance mediated by the alteration of a shared Cry receptor binding site might render all three Cry toxins ineffective.
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Hiltpold I, Adamczyk JJ, Higdon ML, Clark TL, Ellersieck MR, Hibbard BE. Carbon isotope ratios document that the elytra of western corn rootworm (Coleoptera: Chrysomelidae) reflects adult versus larval feeding and later instar larvae prefer Bt corn to alternate hosts. ENVIRONMENTAL ENTOMOLOGY 2014; 43:840-848. [PMID: 24874160 DOI: 10.1603/en13248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In much of the Corn Belt and parts of Europe, the western corn rootworm, Diabrotica virgifera virgifera LeConte, is the most important insect pest of maize. The need for additional basic knowledge of this pest has been highlighted while developing resistance management plans for insecticidal genetically modified crops. This study evaluated the possibility of tracking feeding habits of western corn rootworm larvae using stable carbon isotope signatures. Plants accumulate different ratios of (13)C:(12)C isotopes, usually expressed as δ(13)C, according to whether they use the C3 or C4 photosynthetic pathway. Herbivore biomass is expected to reflect the δ(13)C of the food they eat. For the current experiment, western corn rootworm larvae were grown on different species of plants exhibiting different δ(13)C values. The δ(13)C values were then measured in elytra of emerged beetles. When beetles were unfed, biomass reflected larval feeding. When beetles were fed for 31 d postemergence, δ(13)C values of elytra almost exclusively reflected adult feeding. These results suggest the use of caution in the interpretation of δ(13)C data aiming to document larval diet history when adult feeding history is unknown. The technique was also used to evaluate western corn rootworm larval choice between alternate hosts and maize with and without genetically modified (Bt) traits aimed at their control. Propensity for feeding on alternate hosts versus maize was biased toward feeding on maize regardless whether the maize had Bt or not, suggesting western corn rootworm larvae were not repelled by Bt. These data will be helpful for regulators in interpreting western corn rootworm feeding data on Bt maize.
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Affiliation(s)
- Ivan Hiltpold
- Division of Plant Science, University of Missouri, 205 Curtis Hall, Columbia, MO 65211, USA
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45
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García-Robles I, Ochoa-Campuzano C, Fernández-Crespo E, Camañes G, Martínez-Ramírez AC, González-Bosch C, García-Agustín P, Rausell C, Real MD. Combining hexanoic acid plant priming with Bacillus thuringiensis insecticidal activity against Colorado potato beetle. Int J Mol Sci 2013; 14:12138-56. [PMID: 23743826 PMCID: PMC3709778 DOI: 10.3390/ijms140612138] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 05/29/2013] [Accepted: 05/31/2013] [Indexed: 01/17/2023] Open
Abstract
Interaction between insect herbivores and host plants can be modulated by endogenous and exogenous compounds present in the source of food and might be successfully exploited in Colorado potato beetle (CPB) pest management. Feeding tests with CPB larvae reared on three solanaceous plants (potato, eggplant and tomato) resulted in variable larval growth rates and differential susceptibility to Bacillus thuringiensis Cry3Aa toxin as a function of the host plant. An inverse correlation with toxicity was observed in Cry3Aa proteolytic patterns generated by CPB midgut brush-border membrane vesicles (BBMV) from Solanaceae-fed larvae, being the toxin most extensively proteolyzed on potato, followed by eggplant and tomato. We found that CPB cysteine proteases intestains may interact with Cry3Aa toxin and, in CPB BBMV from larvae fed all three Solanaceae, the toxin was able to compete for the hydrolysis of a papain substrate. In response to treatment with the JA-dependent plant inducer Hexanoic acid (Hx), we showed that eggplant reduced OPDA basal levels and both, potato and eggplant induced JA-Ile. CPB larvae feeding on Hx-induced plants exhibited enhanced Cry3Aa toxicity, which correlated with altered papain activity. Results indicated host-mediated effects on B. thuringiensis efficacy against CPB that can be enhanced in combination with Hx plant induction.
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Affiliation(s)
- Inmaculada García-Robles
- Department of Genetics, University of Valencia, Dr. Moliner 50, Burjassot 46100, Valencia, Spain; E-Mails: (I.G.-R.); (C.O.-C.); (A.C.M.-R.); (C.R.)
| | - Camila Ochoa-Campuzano
- Department of Genetics, University of Valencia, Dr. Moliner 50, Burjassot 46100, Valencia, Spain; E-Mails: (I.G.-R.); (C.O.-C.); (A.C.M.-R.); (C.R.)
| | - Emma Fernández-Crespo
- Biochemistry and Biotechnology Laboratory, Plant Physiology Area, Department CAMN, University Jaume I, Castellón 12071, Spain; E-Mails: (E.F.-C.); (G.C.); (P.G.-A.)
| | - Gemma Camañes
- Biochemistry and Biotechnology Laboratory, Plant Physiology Area, Department CAMN, University Jaume I, Castellón 12071, Spain; E-Mails: (E.F.-C.); (G.C.); (P.G.-A.)
| | - Amparo C. Martínez-Ramírez
- Department of Genetics, University of Valencia, Dr. Moliner 50, Burjassot 46100, Valencia, Spain; E-Mails: (I.G.-R.); (C.O.-C.); (A.C.M.-R.); (C.R.)
| | - Carmen González-Bosch
- Department of Biochemistry and Molecular Biology, University of Valencia, IATA (CSIC), Paterna, Valencia 46980, Spain; E-Mail:
| | - Pilar García-Agustín
- Biochemistry and Biotechnology Laboratory, Plant Physiology Area, Department CAMN, University Jaume I, Castellón 12071, Spain; E-Mails: (E.F.-C.); (G.C.); (P.G.-A.)
| | - Carolina Rausell
- Department of Genetics, University of Valencia, Dr. Moliner 50, Burjassot 46100, Valencia, Spain; E-Mails: (I.G.-R.); (C.O.-C.); (A.C.M.-R.); (C.R.)
| | - María Dolores Real
- Department of Genetics, University of Valencia, Dr. Moliner 50, Burjassot 46100, Valencia, Spain; E-Mails: (I.G.-R.); (C.O.-C.); (A.C.M.-R.); (C.R.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +34-963-543-397; Fax: +34-963-543-029
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Retargeting of the Bacillus thuringiensis toxin Cyt2Aa against hemipteran insect pests. Proc Natl Acad Sci U S A 2013; 110:8465-70. [PMID: 23650347 DOI: 10.1073/pnas.1222144110] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although transgenic crops expressing Bacillus thuringiensis (Bt) toxins have been used successfully for management of lepidopteran and coleopteran pest species, the sap-sucking insects (Hemiptera) are not particularly susceptible to Bt toxins. To overcome this limitation, we demonstrate that addition of a short peptide sequence selected for binding to the gut of the targeted pest species serves to increase toxicity against said pest. Insertion of a 12-aa pea aphid gut-binding peptide by adding to or replacing amino acids in one of three loops of the Bt cytolytic toxin, Cyt2Aa, resulted in enhanced binding and toxicity against both the pea aphid, Acyrthosiphon pisum, and the green peach aphid, Myzus persicae. This strategy may allow for transgenic plant-mediated suppression of other hemipteran pests, which include some of the most important pests of global agriculture.
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Bacillus thuringiensis Cry34Ab1/Cry35Ab1 interactions with western corn rootworm midgut membrane binding sites. PLoS One 2013; 8:e53079. [PMID: 23308139 PMCID: PMC3537739 DOI: 10.1371/journal.pone.0053079] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 11/23/2012] [Indexed: 11/19/2022] Open
Abstract
Background Bacillus thuringiensis (Bt) Cry34Ab1/Cry35Ab1 are binary insecticidal proteins that are co-expressed in transgenic corn hybrids for control of western corn rootworm, Diabrotica virgifera virgifera LeConte. Bt crystal (Cry) proteins with limited potential for field-relevant cross-resistance are used in combination, along with non-transgenic corn refuges, as a strategy to delay development of resistant rootworm populations. Differences in insect midgut membrane binding site interactions are one line of evidence that Bt protein mechanisms of action differ and that the probability of receptor-mediated cross-resistance is low. Methodology/Principal Findings Binding site interactions were investigated between Cry34Ab1/Cry35Ab1 and coleopteran active insecticidal proteins Cry3Aa, Cry6Aa, and Cry8Ba on western corn rootworm midgut brush border membrane vesicles (BBMV). Competitive binding of radio-labeled proteins to western corn rootworm BBMV was used as a measure of shared binding sites. Our work shows that 125I-Cry35Ab1 binds to rootworm BBMV, Cry34Ab1 enhances 125I-Cry35Ab1 specific binding, and that 125I-Cry35Ab1 with or without unlabeled Cry34Ab1 does not share binding sites with Cry3Aa, Cry6Aa, or Cry8Ba. Two primary lines of evidence presented here support the lack of shared binding sites between Cry34Ab1/Cry35Ab1 and the aforementioned proteins: 1) No competitive binding to rootworm BBMV was observed for competitor proteins when used in excess with 125I-Cry35Ab1 alone or combined with unlabeled Cry34Ab1, and 2) No competitive binding to rootworm BBMV was observed for unlabeled Cry34Ab1 and Cry35Ab1, or a combination of the two, when used in excess with 125I-Cry3Aa, or 125I-Cry8Ba. Conclusions/Significance Combining two or more insecticidal proteins active against the same target pest is one tactic to delay the onset of resistance to either protein. We conclude that Cry34Ab1/Cry35Ab1 are compatible with Cry3Aa, Cry6Aa, or Cry8Ba for deployment as insect resistance management pyramids for in-plant control of western corn rootworm.
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Transgenic approaches to western corn rootworm control. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2013; 136:135-62. [PMID: 23604211 DOI: 10.1007/10_2013_195] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) is a significant corn pest throughout the United States corn belt. Rootworm larvae feed on corn roots causing yield losses and control expenditures that are estimated to exceed US$1 billion annually. Traditional management practices to control rootworms such as chemical insecticides or crop rotation have suffered reduced effectiveness due to the development of physiological and behavioral resistance. Transgenic maize expressing insecticidal proteins are very successful in protecting against rootworm damage and preserving corn yield potential. However, the high rate of grower adoption and early reliance on hybrids expressing a single mode of action and low-dose traits threatens the durability of commercialized transgenic rootworm technology for rootworm control. A summary of current transgenic approaches for rootworm control and the corresponding insect resistance management practices is included. An overview of potential new modes of action based on insecticidal proteins, and especially RNAi targeting mRNA coding for essential insect proteins is provided.
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Romeis J, Raybould A, Bigler F, Candolfi MP, Hellmich RL, Huesing JE, Shelton AM. Deriving criteria to select arthropod species for laboratory tests to assess the ecological risks from cultivating arthropod-resistant genetically engineered crops. CHEMOSPHERE 2013; 90:901-9. [PMID: 23062830 DOI: 10.1016/j.chemosphere.2012.09.035] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 07/18/2012] [Accepted: 09/08/2012] [Indexed: 05/06/2023]
Abstract
UNLABELLED Arthropods form a major part of the biodiversity in agricultural landscapes. Many species are valued because they provide ecosystem services, including biological control, pollination and decomposition, or because they are of conservation interest. Some arthropods reduce crop yield and quality, and conventional chemical pesticides, biological control agents and genetically engineered (GE) crops are used to control them. A common concern addressed in the ecological risk assessment (ERA) that precedes regulatory approval of these pest control methods is their potential to adversely affect valued non-target arthropods (NTAs). A key concept of ERA is early-tier testing using worst-case exposure conditions in the laboratory and surrogate test species that are most likely to reveal an adverse effect. If no adverse effects are observed in those species at high exposures, confidence of negligible ecological risk from the use of the pest control method is increased. From experience with chemical pesticides and biological control agents, an approach is proposed for selecting test species for early-tier ERA of GE arthropod-resistant crops. Surrogate species should be selected that most closely meet three criteria: (i) Potential sensitivity: species should be the most likely to be sensitive to the arthropod-active compound based on the known spectrum of activity of the active ingredient, its mode of action, and the phylogenetic relatedness of the test and target species; (ii) RELEVANCE species should be representative of valued taxa or functional groups that are most likely to be exposed to the arthropod-active compound in the field; and (iii) Availability and reliability: suitable life-stages of the test species must be obtainable in sufficient quantity and quality, and validated test protocols must be available that allow consistent detection of adverse effects on ecologically relevant parameters. Our proposed approach ensures that the most suitable species are selected for testing and that the resulting data provide the most rigorous test of the risk hypothesis of no adverse effect in order to increase the quality and efficiency of ERAs for cultivation of GE crops.
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Affiliation(s)
- Jörg Romeis
- Agroscope Reckenholz-Tänikon Research Station ART, Reckenholzstr. 191, 8046 Zurich, Switzerland.
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Chougule NP, Bonning BC. Toxins for transgenic resistance to hemipteran pests. Toxins (Basel) 2012; 4:405-29. [PMID: 22822455 PMCID: PMC3398418 DOI: 10.3390/toxins4060405] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2012] [Revised: 05/16/2012] [Accepted: 05/25/2012] [Indexed: 01/13/2023] Open
Abstract
The sap sucking insects (Hemiptera), which include aphids, whiteflies, plant bugs and stink bugs, have emerged as major agricultural pests. The Hemiptera cause direct damage by feeding on crops, and in some cases indirect damage by transmission of plant viruses. Current management relies almost exclusively on application of classical chemical insecticides. While the development of transgenic crops expressing toxins derived from the bacterium Bacillus thuringiensis (Bt) has provided effective plant protection against some insect pests, Bt toxins exhibit little toxicity against sap sucking insects. Indeed, the pest status of some Hemiptera on Bt-transgenic plants has increased in the absence of pesticide application. The increased pest status of numerous hemipteran species, combined with increased prevalence of resistance to chemical insecticides, provides impetus for the development of biologically based, alternative management strategies. Here, we provide an overview of approaches toward transgenic resistance to hemipteran pests.
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Affiliation(s)
| | - Bryony C. Bonning
- Author to whom correspondence should be addressed; ; Tel.: +1-515-294-1989; Fax: +1-515-294-5957
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