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Zwack PJ, Wu Y, Leininger C, Williams J, Richards EE, Wood C, Wong S, Bramlett M. Characterization of the mode of action of eCry1Gb.1Ig, a fall armyworm (Spodoptera frugiperda) active protein, with a novel site of action. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2024; 201:105881. [PMID: 38685247 DOI: 10.1016/j.pestbp.2024.105881] [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: 02/21/2024] [Revised: 03/14/2024] [Accepted: 03/17/2024] [Indexed: 05/02/2024]
Abstract
Insect pests cause immense agronomic losses worldwide. One of the most destructive of major crops is the Fall Armyworm (Spodoptera frugiperda, FAW). The ability to migrate long distances, a prodigious appetite, and a demonstrated ability to develop resistance to insecticides, make it a difficult target to control. Insecticidal proteins, for example those produced by the bacterium Bacillus thuringiensis, are among the safest and most effective insect control agents. Genetically modified (GM) crops expressing such proteins are a key part of a successful integrated pest management (IPM) program for FAW. However, due to the development of populations resistant to commercialized GM products, new GM traits are desperately needed. Herein, we describe a further characterization of the newly engineered trait protein eCry1Gb.1Ig. Similar to other well characterized Cry proteins, eCry1Gb.1Ig is shown to bind FAW midgut cells and induce cell-death. Binding competition assays using trait proteins from other FAW-active events show a lack of competition when binding FAW brush border membrane vesicles (BBMVs) and when utilizing non-pore-forming versions as competitors in in vivo bioassays. Similarly, insect cell lines expressing SfABCC2 and SfABCC3 (well characterized receptors of existing commercial Cry proteins) are insensitive to eCry1Gb.1Ig. These findings are consistent with results from our previous work showing that eCry1Gb.1Ig is effective in controlling insects with resistance to existing traits. This underscores the value of eCry1Gb.1Ig as a new GM trait protein with a unique site-of-action and its potential positive impact to global food production.
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Affiliation(s)
- Paul J Zwack
- Syngenta Crop Protection LLC, Research Triangle Park, NC, USA.
| | - Yuexuan Wu
- Syngenta Crop Protection LLC, Research Triangle Park, NC, USA
| | - Chris Leininger
- Syngenta Crop Protection LLC, Research Triangle Park, NC, USA
| | | | | | - Chase Wood
- Syngenta Crop Protection LLC, Research Triangle Park, NC, USA
| | - Sarah Wong
- Syngenta Crop Protection LLC, Research Triangle Park, NC, USA
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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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de Oliveira JL, Gómez I, Sánchez J, Soberón M, Polanczyk RA, Bravo A. Performance insights into spray-dryer microencapsulated Bacillus thuringiensis cry pesticidal proteins with gum arabic and maltodextrin for effective pest control. Appl Microbiol Biotechnol 2024; 108:181. [PMID: 38285209 PMCID: PMC10824793 DOI: 10.1007/s00253-023-12990-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 11/28/2023] [Accepted: 12/26/2023] [Indexed: 01/30/2024]
Abstract
Bacillus thuringiensis (Bt) produces crystals composed mainly of Cry pesticidal proteins with insecticidal activity against pests but are highly susceptible to degradation by abiotic factors. In this sense, encapsulation techniques are designed to improve their performance and lifetime. However, the effects of polymeric matrix encapsulation such as gum arabic and maltodextrin by spray-dryer in the mechanisms of action of Bt kurstaki and Bt aizawai are unknown. We analyzed crystal solubilization, protoxin activation, and receptor binding after microencapsulation and compared them with commercial non-encapsulated products. Microencapsulation did not alter protein crystal solubilization, providing 130 kDa (Cry1 protoxin) and 70 kDa (Cry2 protoxin). Activation with trypsin, chymotrypsin, and larval midgut juice was analyzed, showing that this step is highly efficient, and the protoxins were cleaved producing similar ~ 55 to 65 kDa activated proteins for both formulations. Binding assays with brush border membrane vesicles of Manduca sexta and Spodoptera frugiperda larvae provided a similar binding for both formulations. LC50 bioassays showed no significant differences between treatments but the microencapsulated treatment provided higher mortality against S. frugiperda when subjected to UV radiation. Microencapsulation did not affect the mechanism of action of Cry pesticidal proteins while enhancing protection against UV radiation. These data will contribute to the development of more efficient Bt biopesticide formulations. KEY POINTS: • Microencapsulation did not affect the mechanisms of action of Cry pesticidal proteins produced by Bt. • Microencapsulation provided protection against UV radiation for Bt-based biopesticides. • The study's findings can contribute to the development of more efficient Bt biopesticide formulations.
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Affiliation(s)
- Jhones Luiz de Oliveira
- Department of Agricultural Production Sciences, Faculty of Agronomy and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal, São Paulo, 14884-900, Brazil
- Department of Molecular Microbiology, Instituto de Biotecnología, Universidad Nacional Autónoma de Mexico, Cuernavaca, Morelos, Mexico
| | - Isabel Gómez
- Department of Molecular Microbiology, Instituto de Biotecnología, Universidad Nacional Autónoma de Mexico, Cuernavaca, Morelos, Mexico
| | - Jorge Sánchez
- Department of Molecular Microbiology, Instituto de Biotecnología, Universidad Nacional Autónoma de Mexico, Cuernavaca, Morelos, Mexico
| | - Mario Soberón
- Department of Molecular Microbiology, Instituto de Biotecnología, Universidad Nacional Autónoma de Mexico, Cuernavaca, Morelos, Mexico
| | - Ricardo Antonio Polanczyk
- Department of Agricultural Production Sciences, Faculty of Agronomy and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal, São Paulo, 14884-900, Brazil.
| | - Alejandra Bravo
- Department of Molecular Microbiology, Instituto de Biotecnología, Universidad Nacional Autónoma de Mexico, Cuernavaca, Morelos, Mexico.
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Alves GB, de Oliveira EE, Jumbo LOV, dos Santos GR, dos Santos MM, Ootani MA, Ribeiro BM, Aguiar RWDS. Genomic–proteomic analysis of a novel Bacillus thuringiensis strain: toxicity against two lepidopteran pests, abundance of Cry1Ac5 toxin, and presence of InhA1 virulence factor. Arch Microbiol 2023; 205:143. [PMID: 36967401 DOI: 10.1007/s00203-023-03479-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 03/09/2023] [Accepted: 03/09/2023] [Indexed: 03/28/2023]
Abstract
Bacillus thuringiensis (Bt) is a biological alternative to the indiscriminate use of chemical insecticides in agriculture. Due to resistance development on insect pests to Bt crops, isolating novel Bt strains is a strategy for screening new pesticidal proteins or strains containing toxin profile variety that can delay resistance. Besides, the combined genomic and proteomic approaches allow identifying pesticidal proteins and virulence factors accurately. Here, the genome of a novel Bt strain (Bt TOL651) was sequenced, and the proteins from the spore-crystal mixture were identified by proteomic analysis. Toxicity bioassays with the spore-crystal mixture against larvae of Diatraea saccharalis and Anticarsia gemmatalis, key pests of sugarcane and soybean, respectively, were performed. The toxicity of Bt TOL651 varies with the insect; A. gemmatalis (LC50 = 1.45 ng cm-2) is more susceptible than D. saccharalis (LC50 = 73.77 ng cm-2). Phylogenetic analysis of the gyrB gene indicates that TOL651 is related to Bt kenyae strains. The genomic analysis revealed the presence of cry1Aa18, cry1Ac5, cry1Ia44, and cry2Aa9 pesticidal genes. Virulence factor genes such as phospholipases (plcA, piplc), metalloproteases (inhA), hemolysins (cytK, hlyIII, hblA, hblC, hblD), and enterotoxins (nheA, nheB, nheC) were also identified. The combined use of the genomic and proteomic data indicated the expression of Cry1Aa18, Cry1Ac5, and Cry2Aa9 proteins, with Cry1Ac5 being the most abundant. InhA1 also was expressed and may contribute to Bt TOL651 pathogenicity. These results provide Bt TOL651 as a new tool for the biocontrol of lepidopteran pests.
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de Oliveira JA, Negri BF, Hernández-Martínez P, Basso MF, Escriche B. Mpp23Aa/Xpp37Aa Insecticidal Proteins from Bacillus thuringiensis (Bacillales: Bacillaceae) Are Highly Toxic to Anthonomus grandis (Coleoptera: Curculionidae) Larvae. Toxins (Basel) 2023; 15:55. [PMID: 36668875 PMCID: PMC9865532 DOI: 10.3390/toxins15010055] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/02/2023] [Accepted: 01/03/2023] [Indexed: 01/11/2023] Open
Abstract
The beetle Anthonomus grandis Boheman, 1843, is the main cotton pest, causing enormous losses in cotton. The breeding of genetically modified plants with A. grandis resistance is seen as an important control strategy. However, the identification of molecules with high toxicity to this insect remains a challenge. The susceptibility of A. grandis larvae to proteins (Cry1Ba, Cry7Ab, and Mpp23Aa/Xpp37Aa) from Bacillus thuringiensis Berliner, 1915, with toxicity reported against Coleopteran, has been evaluated. The ingestion of different protein concentrations (which were incorporated into an artificial diet) by the larvae was tested in the laboratory, and mortality was evaluated after one week. All Cry proteins tested exhibited higher toxicity than that the untreated artificial diet. These Cry proteins showed similar results to the control Cry1Ac, with low toxicity to A. grandis, since it killed less than 50% of larvae, even at the highest concentration applied (100 μg·g-1). Mpp/Xpp proteins provided the highest toxicity with a 0.18 μg·g-1 value for the 50% lethal concentration. Importantly, this parameter is the lowest ever reported for this insect species tested with B. thuringiensis proteins. This result highlights the potential of Mpp23Aa/Xpp37Aa for the development of a biotechnological tool aiming at the field control of A. grandis.
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Affiliation(s)
- Jéssica A. de Oliveira
- Laboratório de Prospecção de Cepas e Genes, Instituto Mato-Grossense do Algodão (IMAmt), Rondonópolis 78740-970, Mato Grosso, Brazil
| | - Bárbara F. Negri
- Laboratório de Biologia Molecular e Transformação de Plantas, Instituto Mato-Grossense do Algodão (IMAmt), Rondonópolis 78740-970, Mato Grosso, Brazil
| | - Patricia Hernández-Martínez
- Departamento de Genética, Instituto de Biotecnología y Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Valencia, Spain
| | - Marcos F. Basso
- Dipartimento di Biologia e Incubatore Universitario Fiorentino, Dipartimento di Biologia, Università degli Studi di Firenze, 50019 Sesto Fiorentino, Firenze, Italy
| | - Baltasar Escriche
- Departamento de Genética, Instituto de Biotecnología y Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Valencia, Spain
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Resistance of Cabbage Loopers to Bacillus thuringiensis (Bt) Toxin Cry1F and to Dual-Bt Toxin WideStrike Cotton Plants. Appl Environ Microbiol 2022; 88:e0119422. [PMID: 36200769 PMCID: PMC9599322 DOI: 10.1128/aem.01194-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Cry proteins from Bacillus thuringiensis (Bt) are major insecticidal toxins in formulated Bt sprays and are expressed in genetically engineered Bt crops for insect pest control. However, the widespread application of Bt toxins in the field imposes strong selection pressure on target insects, leading to the evolution of insect resistance to the Bt toxins. Identification and understanding of mechanisms of insect resistance to Bt toxins are an important approach for dissecting the modes of action of Bt toxins and providing knowledge necessary for the development of resistance management technologies. In this study, cabbage looper (Trichoplusia ni) strains resistant to the transgenic dual-Bt toxin WideStrike cotton plants, which express Bt toxins Cry1Ac and Cry1F, were selected from T. ni strains resistant to the Bt formulation Bt-DiPel. The WideStrike-resistant T. ni larvae were confirmed to be resistant to both Bt toxins Cry1Ac and Cry1F. From the WideStrike-resistant T. ni, the Cry1F resistance trait was further isolated to establish a T. ni strain resistant to Cry1F only. The levels of Cry1F resistance in the WideStrike-resistant and the Cry1F-resistant strains were determined, and the inheritance of the Cry1F-resistant trait in the two strains was characterized. Genetic association analysis of the Cry1F resistance trait indicated that the Cry1F resistance in T. ni isolated in this study is not shared with the Cry1Ac resistance mechanism nor is it associated with a mutation in the ABCC2 gene, as has so far been reported in Cry1F-resistant insects. IMPORTANCE Insecticidal toxins from Bacillus thuringiensis (Bt) are highly effective for insect control in agriculture. However, the widespread application of Bt toxins exerts strong selection for Bt resistance in insect populations. The continuing success of Bt biotechnology for pest control requires the identification of resistance and understanding of the mechanisms of resistance to Bt toxins. Cry1F is an important Bt toxin used in transgenic cotton, maize, and soybean varieties adopted widely for insect control. To understand the mode of action of Cry1F and mechanisms of Cry1F resistance in insects, it is important to identify Cry1F-specific resistance and the resistance mechanisms. In this study, Trichoplusia ni strains resistant to commercial "WideStrike" cotton plants that express Bt toxins Cry1Ac and Cry1F were selected, and a Cry1F-specific resistant strain was isolated. The isolation of the novel Cry1F-specific resistance in the T. ni provided an invaluable biological system to discover a Cry1F-specific novel resistance mechanism.
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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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Lv F, Wang P, Zhang E, Ma L, Gao L, Yang R, Wang Q, Li Y. Efficient Transformation of Catalpa bungei Shows Crystal Genes Conferring Resistance to the Shoot Borer Omphisa plagialis. FRONTIERS IN PLANT SCIENCE 2021; 12:777411. [PMID: 35003162 PMCID: PMC8739885 DOI: 10.3389/fpls.2021.777411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 11/26/2021] [Indexed: 06/14/2023]
Abstract
Although Catalpa bungei is a forest plant with considerable economic and ornamental value in China, its wood and decorative qualities are constrained by insect pests such as the shoot borer Omphisa plagialis (Lepidoptera). Overexpressing insect resistance genes such as crystal genes to develop an insect-resistant variety of C. bungei is an environmental and ecological approach. However, genotype limitations and low regeneration rates of embryogenic calli (EC) inhibit the development of transformation and the insect-resistant gene expression system in C. bungei. Here, we first established embryogenic callus induction and regeneration systems of five genotypes using mature seed and stem segment explants; the highest induction and regeneration rates of EC were 39.89 and 100%, respectively. Next, an efficient and stable Agrobacterium-mediated genetic transformation system was developed from EC and its positive frequency was up to 92.31%. Finally, using the transformation system, 15 and 22 transgenic C. bungei lines that expressed Cry2A and Cry9Aa-like were generated, respectively. These transgenic lines that exhibited significantly higher resistance to O. plagialis in the laboratory and field have great promise for meeting the challenge of future pest management under changing climatic conditions. Additionally, this efficient, fast, and stable transformation system could be a potential tool for gene function analysis and forest tree genetic improvement.
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Affiliation(s)
| | | | | | | | | | | | | | - Ya Li
- Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province & Chinese Academy of Sciences, Nanjing, China
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Shaw TJ, Paula-Moraes SV, Hahn PG, Specht A. Seasonal Flight Patterns of Chrysodeixis includens (Lepidoptera: Noctuidae) in the Florida Panhandle and Inventory of Plusiine Species Cross-Attracted to Synthetic Pheromone. JOURNAL OF ECONOMIC ENTOMOLOGY 2021; 114:2315-2325. [PMID: 34595520 DOI: 10.1093/jee/toab179] [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: 03/02/2021] [Indexed: 06/13/2023]
Abstract
Chysodeixis includens (Walker) is a polyphagous economic pest in agricultural landscapes. To detect the occurrence of this pest in the field, trapping using sex pheromone lures is often implemented. However, other plusiine species are cross-attracted to these lures and may be misidentified as C. includens due to their morphological similarities. The objectives of this study were to provide region-specific information on the abundance of C. includens throughout the year as well as document the occurrence of related plusiines cross-attracted to C. includens sex pheromone traps in the Florida Panhandle. Twelve commercial fields of peanut and twelve commercial fields of cotton located across Escambia, Santa Rosa, and Jackson counties were monitored with Trécé delta traps baited with C. includens sex pheromone lures (Alpha Scents, Inc.; West Linn, OR) from June 2017 to June 2019. There was no difference in C. includens flight across dryland or irrigated fields. Identifications revealed that in addition to C. includens, the following species of the subfamily Plusiinae were crossed-attracted: Argyrogramma verruca (Fabricius) (Lepidoptera: Noctuidae), Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae), Ctenoplusia oxygramma (Geyer) (Lepidoptera: Noctuidae), and Rachiplusia ou (Guenée) (Lepidoptera: Noctuidae). The occurrence of each species in the region and their flight phenology are documented. Chysodeixis includens abundance was greatest in September and decreased through December. Due to the high abundance of C. oxygramma and similar flight phenology to C. includens, this is the likeliest species to skew estimations and influence management decisions of C. includens, especially early in the crop season, when C. includens abundance is low.
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Affiliation(s)
- T J Shaw
- Entomology and Nematology Department, West Florida Research and Education Center, University of Florida, 4253 Experiment Drive, Hwy 182, Jay, FL, USA
| | - S V Paula-Moraes
- Entomology and Nematology Department, West Florida Research and Education Center, University of Florida, 4253 Experiment Drive, Hwy 182, Jay, FL, USA
| | - P G Hahn
- Entomology and Nematology Department, University of Florida, 2109 Steinmetz Hall, Building 970 Natural Area Dr., Gainesville, FL, USA
| | - A Specht
- Embrapa Cerrados, Planaltina, 73310-970, DF, Brazil
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Evaluation of Reference Genes and Expression Level of Genes Potentially Involved in the Mode of Action of Cry1Ac and Cry1F in a Susceptible Reference Strain of Chrysodeixis includens. INSECTS 2021; 12:insects12070598. [PMID: 34209276 PMCID: PMC8304518 DOI: 10.3390/insects12070598] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 06/22/2021] [Accepted: 06/29/2021] [Indexed: 11/17/2022]
Abstract
Simple Summary Soybean looper (a moth species) is a major pest of soybean plants in the American continent and its larvae need to be kept under economic damage thresholds to guarantee sustainable yields. Soybean looper control relies mostly on the use of insecticides and genetically modified crops expressing Bacillus thuringiensis (Bt) insecticidal proteins. Due to the high selection pressure exerted by these control measures, resistance has developed to different insecticides and Bt proteins. Here, we tested the basal sensitivity of a soybean looper laboratory reference strain against two insecticidal proteins and determined the level of expression of potential receptors of these proteins across all (six) larval stages. Furthermore, we identified stable reference genes across all larval stages to normalize gene expression data obtained by quantitative polymerase chain reaction (qPCR). The results presented in this communication are useful to support future studies on insecticide and insecticidal protein resistance in soybean looper. Abstract Soybean looper (SBL), Chrysodeixis includens (Walker), is one of the major lepidopteran pests of soybean in the American continent. SBL control relies mostly on the use of insecticides and genetically modified crops expressing Bacillus thuringiensis (Bt) insecticidal Cry proteins. Due to the high selection pressure exerted by these control measures, resistance has developed to different insecticides and Bt proteins. Nevertheless, studies on the mechanistic background are still scarce. Here, the susceptibility of the laboratory SBL-Benzon strain to the Bt proteins Cry1Ac and Cry1F was determined in diet overlay assays and revealed a greater activity of Cry1Ac than Cry1F, thus confirming results obtained for other sensitive SBL strains. A reference gene study across larval stages with four candidate genes revealed that RPL10 and EF1 were the most stable genes for normalization of gene expression data obtained by RT-qPCR. Finally, the basal expression levels of eight potential Bt protein receptor genes in six larval instars were analyzed, including ATP-binding cassette (ABC) transporters, alkaline phosphatase, aminopeptidases, and cadherin. The results presented here provide fundamental knowledge to support future SBL resistance studies.
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Chen D, Moar WJ, Jerga A, Gowda A, Milligan JS, Bretsynder EC, Rydel TJ, Baum JA, Semeao A, Fu X, Guzov V, Gabbert K, Head GP, Haas JA. Bacillus thuringiensis chimeric proteins Cry1A.2 and Cry1B.2 to control soybean lepidopteran pests: New domain combinations enhance insecticidal spectrum of activity and novel receptor contributions. PLoS One 2021; 16:e0249150. [PMID: 34138865 PMCID: PMC8211277 DOI: 10.1371/journal.pone.0249150] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 02/07/2021] [Indexed: 01/08/2023] Open
Abstract
Two new chimeric Bacillus thuringiensis (Bt) proteins, Cry1A.2 and Cry1B.2, were constructed using specific domains, which provide insecticidal activity against key lepidopteran soybean pests while minimizing receptor overlaps between themselves, current, and soon to be commercialized plant incorporated protectants (PIP's) in soybean. Results from insect diet bioassays demonstrate that the recombinant Cry1A.2 and Cry1B.2 are toxic to soybean looper (SBL) Chrysodeixis includens Walker, velvetbean caterpillar (VBC) Anticarsia gemmatalis Hubner, southern armyworm (SAW) Spodoptera eridania, and black armyworm (BLAW) Spodoptera cosmioides with LC50 values < 3,448 ng/cm2. Cry1B.2 is of moderate activity with significant mortality and stunting at > 3,448 ng/cm2, while Cry1A.2 lacks toxicity against old-world bollworm (OWB) Helicoverpa armigera. Results from disabled insecticidal protein (DIP) bioassays suggest that receptor utilization of Cry1A.2 and Cry1B.2 proteins are distinct from each other and from current, and yet to be commercially available, Bt proteins in soy such as Cry1Ac, Cry1A.105, Cry1F.842, Cry2Ab2 and Vip3A. However, as Cry1A.2 contains a domain common to at least one commercial soybean Bt protein, resistance to this common domain in a current commercial soybean Bt protein could possibly confer at least partial cross resistance to Cry1A2. Therefore, Cry1A.2 and Cry1B.2 should provide two new tools for controlling many of the major soybean insect pests described above.
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Affiliation(s)
- Danqi Chen
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - William J. Moar
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Agoston Jerga
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Anilkumar Gowda
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jason S. Milligan
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | | | - Timothy J. Rydel
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - James A. Baum
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Altair Semeao
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Xiaoran Fu
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Victor Guzov
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Karen Gabbert
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Graham P. Head
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Jeffrey A. Haas
- Bayer Crop Science, Chesterfield, Missouri, United States of America
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12
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Azizoglu U, Jouzani GS, Yilmaz N, Baz E, Ozkok D. Genetically modified entomopathogenic bacteria, recent developments, benefits and impacts: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 734:139169. [PMID: 32460068 DOI: 10.1016/j.scitotenv.2020.139169] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/10/2020] [Accepted: 04/30/2020] [Indexed: 06/11/2023]
Abstract
Entomopathogenic bacteria (EPBs), insect pathogens that produce pest-specific toxins, are environmentally-friendly alternatives to chemical insecticides. However, the most important problem with EPBs application is their limited field stability. Moreover, environmental factors such as solar radiation, leaf temperature, and vapor pressure can affect the pathogenicity of these pathogens and their toxins. Scientists have conducted intensive research to overcome such problems. Genetic engineering has great potential for the development of new engineered entomopathogens with more resistance to adverse environmental factors. Genetically modified entomopathogenic bacteria (GM-EPBs) have many advantages over wild EPBs, such as higher pathogenicity, lower spraying requirements and longer-term persistence. Genetic manipulations have been mostly applied to members of the bacterial genera Bacillus, Lysinibacillus, Pseudomonas, Serratia, Photorhabdus and Xenorhabdus. Although many researchers have found that GM-EPBs can be used safely as plant protection bioproducts, limited attention has been paid to their potential ecological impacts. The main concerns about GM-EPBs and their products are their potential unintended effects on beneficial insects (predators, parasitoids, pollinators, etc.) and rhizospheric bacteria. This review address recent update on the significant role of GM-EPBs in biological control, examining them through different perspectives in an attempt to generate critical discussion and aid in the understanding of their potential ecological impacts.
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Affiliation(s)
- Ugur Azizoglu
- Department of Crop and Animal Production, Safiye Cikrikcioglu Vocational College, Kayseri University, Kayseri, Turkey.
| | - Gholamreza Salehi Jouzani
- Microbial Biotechnology Department, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - Nihat Yilmaz
- Department of Crop and Animal Production, Safiye Cikrikcioglu Vocational College, Kayseri University, Kayseri, Turkey
| | - Ethem Baz
- Laboratory and Veterinary Health Department, Safiye Cikrikcioglu Vocational College, Kayseri University, Kayseri, Turkey
| | - Duran Ozkok
- Department of Crop and Animal Production, Safiye Cikrikcioglu Vocational College, Kayseri University, Kayseri, Turkey
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Rabelo MM, Matos JML, Orozco-Restrepo SM, Paula-Moraes SV, Pereira EJG. Like Parents, Like Offspring? Susceptibility to Bt Toxins, Development on Dual-Gene Bt Cotton, and Parental Effect of Cry1Ac on a Nontarget Lepidopteran Pest. JOURNAL OF ECONOMIC ENTOMOLOGY 2020; 113:1234-1242. [PMID: 32221528 DOI: 10.1093/jee/toaa051] [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: 11/03/2019] [Indexed: 06/10/2023]
Abstract
An important step to devise appropriate pest management strategies for armyworms (Lepidoptera: Noctuidae) in Bacillus thuringiensis Berliner (Bt) crops is to determine the lethal, sublethal, and parental effects of Bt toxins on target and nontarget pest species. Here we documented the susceptibility of black armyworm, Spodoptera cosmioides (Walker), to three Cry toxins and its life-history traits feeding on dual-toxin Bt cotton and an artificial diet containing sublethal concentrations of Cry1Ac. In concentration-response bioassays, black armyworm larvae showed low susceptibility to Cry toxins, with 853 ng/cm2 as the lowest value estimated for the median lethal concentration (LC50). The decreasing rank of toxicity was Cry1F, Cry2Aa, and Cry1Ac. Foliage of dual-toxin Bt cotton varieties (Cry1Ac + Cry1F and Cry1Ab + Cry2Ae) caused higher larval mortality than Cry1Ac-expressing cotton. Black armyworms showed reduced larval weight when growing on the Cry1Ac-treated diet, yet they reached adulthood and produced offspring. Interestingly, these larvae were grown on the control diet and showed reduced weight gain associated with the toxin exposure of the previous generation, indicating a parental effect of the exposure to Cy1Ac. The reduced larval weight was recovered in later instars, and there was no significant change in the population fitness of the parental armyworms or their offspring. To our knowledge, this is the first study documenting the parental effects of Bt toxins in insects. These results advance our understanding of potential responses of nontarget species when exposed to Bt toxins and contribute to design pest management programs for armyworms and other nontarget lepidopteran species exposed to Bt crops.
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Affiliation(s)
- Marcelo M Rabelo
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, MG, Brazil
- West Florida Research and Education Center, Department of Entomology and Nematology, University of Florida, Jay, FL
- National Institute of Science and Technology in Plant-Pest Interactions, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - João Marcus L Matos
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, MG, Brazil
- National Institute of Science and Technology in Plant-Pest Interactions, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Silvana M Orozco-Restrepo
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, MG, Brazil
- National Institute of Science and Technology in Plant-Pest Interactions, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Silvana V Paula-Moraes
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, MG, Brazil
- West Florida Research and Education Center, Department of Entomology and Nematology, University of Florida, Jay, FL
| | - Eliseu José G Pereira
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, MG, Brazil
- National Institute of Science and Technology in Plant-Pest Interactions, Universidade Federal de Viçosa, Viçosa, MG, Brazil
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14
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Bel Y, Zack M, Narva K, Escriche B. Specific binding of Bacillus thuringiensis Cry1Ea toxin, and Cry1Ac and Cry1Fa competition analyses in Anticarsia gemmatalis and Chrysodeixis includens. Sci Rep 2019; 9:18201. [PMID: 31796830 PMCID: PMC6890801 DOI: 10.1038/s41598-019-54850-3] [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: 03/18/2019] [Accepted: 11/15/2019] [Indexed: 11/25/2022] Open
Abstract
Anticarsia gemmatalis (velvetbean caterpillar) and Chrysodeixis includens (soybean looper) are two important defoliation pests of soybeans. In the present study, we have investigated the susceptibility and brush border membrane-binding properties of both species to Bacillus thuringiensis Cry1Ea toxin. Bioassays performed in first-instar larvae demonstrated potent activity against both soybean pests in terms of mortality or practical mortality. Competition-binding studies carried out with 125Iodine-labelled Cry1Ea, demonstrated the presence of specific binding sites on the midgut brush border membrane vesicles (BBMV) of both insect species. Heterologous competition-binding experiments indicated that Cry1Ea does not share binding sites with Cry1Ac or Cry1Fa in either soybean pest. This study contributes to the knowledge of Cry1Ea toxicity and midgut binding sites in A. gemmatalis and C. includens and sheds light on the cross-resistance potential of Cry1Ea with other Bt proteins aimed at controlling lepidopteran pests in soybeans.
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Affiliation(s)
- Yolanda Bel
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, , Universitat de València, 46100, Burjassot, Spain
| | - Marc Zack
- Dow AgroSciences, Indianapolis, Indiana, USA
| | - Ken Narva
- Dow AgroSciences, Indianapolis, Indiana, USA
| | - Baltasar Escriche
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, , Universitat de València, 46100, Burjassot, Spain.
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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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Bowling AJ, Sopko MS, Tan SY, Larsen CM, Pence HE, Zack MD. Insecticidal Activity of a Vip3Ab1 Chimera Is Conferred by Improved Protein Stability in the Midgut of Spodoptera eridania. Toxins (Basel) 2019; 11:toxins11050276. [PMID: 31100873 PMCID: PMC6563307 DOI: 10.3390/toxins11050276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 05/08/2019] [Accepted: 05/14/2019] [Indexed: 01/03/2023] Open
Abstract
Vip3A proteins are important for the control of spodopteran pests in crops, including Spodoptera frugiperda (fall armyworm). Native Vip3Ab1 controls S. frugiperda, but it is ineffective against S. eridania (southern armyworm), a major pest of soybean in South America. Recently, a Vip3Ab1 chimera with a modified C-terminus was described, Vip3Ab1-740, which has increased potency against S. eridania while maintaining activity against S. frugiperda. As S. frugiperda and S. eridania are differentially susceptible to Vip3Ab1, experiments were conducted to identify and understand the mechanism by which this expanded potency is conferred. The role of protein stability, processing, and in vivo effects of Vip3Ab1 and Vip3Ab1-740 in both of these species was investigated. Biochemical characterization of the midgut fluids of these two species indicated no obvious differences in the composition and activity of digestive enzymes, which protease inhibitor studies indicated were likely serine proteases. Histological examination demonstrated that both proteins cause midgut disruption in S. frugiperda, while only Vip3Ab1-740 affects S. eridania. Immunolocalization indicated that both proteins were present in the midgut of S. frugiperda, but only Vip3Ab1-740 was detected in the midgut of S. eridania. We conclude that the gain of toxicity of Vip3Ab1-740 to S. eridania is due to an increase in protein stability in the midgut, which was conferred by C-terminal modification.
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Affiliation(s)
| | | | - Sek Yee Tan
- Corteva Agriscience, Indianapolis, IN 46268, USA.
| | | | | | - Marc D Zack
- Corteva Agriscience, Indianapolis, IN 46268, USA.
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17
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Rodrigues-Silva N, Canuto AF, Oliveira DF, Teixeira AF, Santos-Amaya OF, Picanço MC, Pereira EJG. Negative cross-resistance between structurally different Bacillus thuringiensis toxins may favor resistance management of soybean looper in transgenic Bt cultivars. Sci Rep 2019; 9:199. [PMID: 30655612 PMCID: PMC6336840 DOI: 10.1038/s41598-018-35965-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 11/14/2018] [Indexed: 12/30/2022] Open
Abstract
High adoption rates of single-gene Bacillus thuringiensis (Bt) Cry1Ac soybean impose selection pressure for resistance in the soybean looper, Chrysodeixis includens, a major defoliator in soybean and cotton crops. To anticipate and characterize resistance profiles that can evolve, soybean looper larvae collected from field crops in Brazil in 2013 were selected for resistance to Cry1Ac. Using two methods of selection viz., chronic exposure to Cry1Ac cotton leaves and the seven-day larval exposure to purified Cry1Ac on the artificial diet, 31 and 127-fold resistance was obtained in 11 and 6 generations of selection, respectively. The resistance trait had realized heritability of 0.66 and 0.72, respectively, indicating that most of the phenotypic variation in Cry1Ac susceptibility of the soybean looper larvae was due to additive genetic variation. The Cry1Ac-selected populations showed positive cross-resistance to Cry1Ab (6.7-8.7 fold), likely because these Bt toxins have a very similar molecular structure. Importantly, the Cry1Ac-selected populations became more susceptible to Cry2Aa and Cry1Fa, showing negative cross-resistance (up to 6-fold, P < 0.05). These results indicate that Cry1Ac, Cry1Fa, and Cry2A are compatible in a multi-toxin approach to minimize the risk of rapid adaptation of the soybean looper to Bt toxins.
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Affiliation(s)
- Nilson Rodrigues-Silva
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
- National Institute of Science and Technology in Plant-Pest Interactions, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
- Campus do Sertão, Universidade Federal de Sergipe, Nossa Senhora da Glória, SE, 49680-000, Brazil
| | - Afonso F Canuto
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Diogo F Oliveira
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - André F Teixeira
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Oscar F Santos-Amaya
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Marcelo C Picanço
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Eliseu J G Pereira
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil.
- National Institute of Science and Technology in Plant-Pest Interactions, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil.
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Domain III of Cry1Ac Is Critical to Binding and Toxicity against Soybean Looper (Chrysodeixis includens) but Not to Velvetbean Caterpillar (Anticarsia gemmatalis). Toxins (Basel) 2018; 10:toxins10030095. [PMID: 29495466 PMCID: PMC5869383 DOI: 10.3390/toxins10030095] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 02/13/2018] [Accepted: 02/22/2018] [Indexed: 01/10/2023] Open
Abstract
Insecticidal proteins Cry1Ac and Cry2Ac7 from the bacterium Bacillus thuringiensis (Bt) belong to the three-domain family of Bt toxins. Commercial transgenic soybean hybrids produce Cry1Ac to control the larvae of the soybean looper (Chrysodeixis includens) and the velvet bean caterpillar (Anticarsia gemmatalis). The specificity of Cry1Ac is determined by loops extending from domain II and regions of domain III in the three-dimensional structure of the toxin. In this study, we constructed a hybrid toxin (H1.2Ac) containing domains I and II of Cry1Ac and domain III of Cry2Ac7, in an attempt to obtain a protein with enhanced toxicity compared to parental toxins. Bioassays with H1.2Ac revealed toxicity against the larvae of A. gemmatalis but not against C. includens. Saturation binding assays with radiolabeled toxins and midgut brush border membrane vesicles demonstrated no specific H1.2Ac binding to C. includens, while binding in A. gemmatalis was specific and saturable. Results from competition binding assays supported the finding that Cry1Ac specificity against A. gemmatalis is mainly dictated by domain II. Taken together, these distinct interactions with binding sites may help explain the differential susceptibility to Cry1Ac in C. includens and A. gemmatalis, and guide the design of improved toxins against soybean pests.
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Mushtaq R, Behle R, Liu R, Niu L, Song P, Shakoori AR, Jurat-Fuentes JL. Activity of Bacillus thuringiensis Cry1Ie2, Cry2Ac7, Vip3Aa11 and Cry7Ab3 proteins against Anticarsia gemmatalis, Chrysodeixis includens and Ceratoma trifurcata. J Invertebr Pathol 2017; 150:70-72. [PMID: 28919015 DOI: 10.1016/j.jip.2017.09.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 08/29/2017] [Accepted: 09/11/2017] [Indexed: 11/17/2022]
Abstract
Transgenic soybean producing the Cry1Ac insecticidal protein from the bacterium Bacillus thuringiensis is used to control larvae of the velvetbean caterpillar (Anticarsia gemmatalis Hübner) and the soybean looper [Chrysodeixis includens (Walker)]. The main threat to the sustainability of this technology is the development of resistance, which could be delayed by using pyramiding of diverse Bt insecticidal genes. We report high activity of Cry2Ac7 and Vip3Aa11 but not Cry1Ie2 against larvae of A. gemmatalis and C. includens. In addition, we also report anti-feeding activity of Cry1Ie2 and Cry7Ab3 in adults of the bean leaf beetle [Ceratoma trifurcata (Foster)], an alternative pest of soybean.
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Affiliation(s)
- Rubina Mushtaq
- School of Biological Sciences, University of the Punjab, Quaid-i-Azam Campus, Lahore 54590, Pakistan; Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37996, USA
| | - Robert Behle
- Crop Bioprotection Research Unit, USDA-ARS National Center for Agricultural Utilization Research, Peoria, IL 61604, USA
| | - Rongmei Liu
- College of Life Sciences, Northeast Agricultural University, Harbin 150030, China
| | - Lin Niu
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Ping Song
- College of Plant Protection, Agricultural University of Hebei, Baoding, Hebei 071000, China
| | - Abdul Rauf Shakoori
- School of Biological Sciences, University of the Punjab, Quaid-i-Azam Campus, Lahore 54590, Pakistan.
| | - Juan Luis Jurat-Fuentes
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37996, USA.
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Guo D, Luo J, Zhou Y, Xiao H, He K, Yin C, Xu J, Li F. ACE: an efficient and sensitive tool to detect insecticide resistance-associated mutations in insect acetylcholinesterase from RNA-Seq data. BMC Bioinformatics 2017; 18:330. [PMID: 28693417 PMCID: PMC5504734 DOI: 10.1186/s12859-017-1741-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 06/22/2017] [Indexed: 01/11/2023] Open
Abstract
Background Insecticide resistance is a substantial problem in controlling agricultural and medical pests. Detecting target site mutations is crucial to manage insecticide resistance. Though PCR-based methods have been widely used in this field, they are time-consuming and inefficient, and typically have a high false positive rate. Acetylcholinesterases (Ace) is the neural target of the widely used organophosphate (OP) and carbamate insecticides. However, there is not any software available to detect insecticide resistance associated mutations in RNA-Seq data at present. Results A computational pipeline ACE was developed to detect resistance mutations of ace in insect RNA-Seq data. Known ace resistance mutations were collected and used as a reference. We constructed a Web server for ACE, and the standalone software in both Linux and Windows versions is available for download. ACE was used to analyse 971 RNA-Seq data from 136 studies in 7 insect pests. The mutation frequency of each RNA-Seq dataset was calculated. The results indicated that the resistance frequency was 30%–44% in an eastern Ugandan Anopheles population, thus suggesting this resistance-conferring mutation has reached high frequency in these mosquitoes in Uganda. Analyses of RNA-Seq data from the diamondback moth Plutella xylostella indicated that the G227A mutation was positively related with resistance levels to organophosphate or carbamate insecticides. The wasp Nasonia vitripennis had a low frequency of resistant reads (<5%), but the agricultural pests Chilo suppressalis and Bemisia tabaci had a high resistance frequency. All ace reads in the 30 B. tabaci RNA-Seq data were resistant reads, suggesting that insecticide resistance has spread to very high frequency in B. tabaci. Conclusions To the best of our knowledge, the ACE pipeline is the first tool to detect resistance mutations from RNA-Seq data, and it facilitates the full utilization of large-scale genetic data obtained by using next-generation sequencing. Electronic supplementary material The online version of this article (doi:10.1186/s12859-017-1741-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Dianhao Guo
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China.,Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jiapeng Luo
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China.,College of Computer Science and Technology, Nanjing Normal University, Nanjing, 210023, China
| | - Yuenan Zhou
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Huamei Xiao
- College of Life Sciences and Resource Environment, Yichun University, Yichun, 336000, China
| | - Kang He
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Chuanlin Yin
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Jianhua Xu
- College of Life Sciences and Resource Environment, Yichun University, Yichun, 336000, China
| | - Fei Li
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China.
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