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Wang S, Kain W, Wang P. Bacillus thuringiensis Cry1A toxins exert toxicity by multiple pathways in insects. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 102:59-66. [PMID: 30278206 DOI: 10.1016/j.ibmb.2018.09.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/11/2018] [Accepted: 09/28/2018] [Indexed: 06/08/2023]
Abstract
Adoption of biotech crops engineered to express insecticidal toxins from Bacillus thuringiensis (Bt) has revolutionized insect pest control in agriculture. For continuing effective application and development of the environmentally friendly Bt biotechnology, it is fundamental to understand pathways of toxicity of Bt toxins in insects. In this study, mutations were introduced in the midgut cadherin gene in the cabbage looper, Trichoplusia ni, by CRISPR/Cas9 mutagenesis. T. ni strains with mutations in the genes of two major receptors for Bt toxins, the midgut cadherin and ABCC2, and three Cry1A toxins with shared and differential midgut binding sites were used as an experimental system to dissect the roles of the cadherin and ABCC2 in the pathways of toxicity of Bt toxins. Results from assays of responses of the T. ni strains to different Bt toxins revealed that the cadherin and ABCC2 play independent roles in the mode of action of Cry1A toxins and that Bt toxins exert insecticidal activity through multiple redundant pathways of toxicity in insects. Besides the cadherin and ABCC2 pathways, there exists an additional major pathway of toxicity to be identified for Cry1Aa. The results also confirmed that the toxicity of Cry2Ab involves neither the cadherin nor the ABCC2 protein. The multiple pathway model for Bt toxins clarified from this study provided new insights into the molecular modes of action of Bt toxins and mechanisms of insect resistance to Bt toxins.
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Affiliation(s)
- Shaohua Wang
- Department of Entomology, Cornell University, Geneva, NY, 14456, USA; School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Wendy Kain
- Department of Entomology, Cornell University, Geneva, NY, 14456, USA
| | - Ping Wang
- Department of Entomology, Cornell University, Geneva, NY, 14456, USA.
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252
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Carrière Y, Williams JL, Crowder DW, Tabashnik BE. Genotype-specific fitness cost of resistance to Bt toxin Cry1Ac in pink bollworm. PEST MANAGEMENT SCIENCE 2018; 74:2496-2503. [PMID: 29604164 DOI: 10.1002/ps.4928] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 03/28/2018] [Accepted: 03/29/2018] [Indexed: 05/29/2023]
Abstract
BACKGROUND To improve resistance management strategies for Bacillus thuringiensis (Bt) crops, a better understanding of the relative fitness of pest genotypes with resistance alleles in the absence of Bt toxins is needed. Here, we evaluated the impact of costs of resistance to Bt toxin Cry1Ac on the relative fitness of specific pink bollworm (Pectinophora gossypiella) genotypes. We created two heterogeneous strains with an intermediate frequency of mutant cadherin alleles linked with resistance to Cry1Ac, reared the strains on diet without Bt and tracked the decline in frequency of resistant genotypes for 15-30 generations using polymerase chain reaction amplification. We used a population genetics model and sensitivity analyses to estimate the relative fitness of resistant genotypes. RESULTS Costs were completely recessive in one strain and almost completely recessive in the other. Estimates of the decline in relative fitness of the resistant homozygotes fed on a diet without Bt were 14-22% in one strain and 21-36% in the other. CONCLUSION Our genotype-specific cost estimates and the results of studies discussed herein indicate that costs associated with resistance to Bt are often large enough to significantly delay the evolution of resistance to pyramided Bt crops in pests with recessive inheritance of resistance. © 2018 Society of Chemical Industry.
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Affiliation(s)
- Yves Carrière
- Department of Entomology, University of Arizona, Tucson, USA
| | | | - David W Crowder
- Department of Entomology, Washington State University, Pullman, USA
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Gillis A, Fayad N, Makart L, Bolotin A, Sorokin A, Kallassy M, Mahillon J. Role of plasmid plasticity and mobile genetic elements in the entomopathogen Bacillus thuringiensis serovar israelensis. FEMS Microbiol Rev 2018; 42:829-856. [PMID: 30203090 PMCID: PMC6199540 DOI: 10.1093/femsre/fuy034] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 09/06/2018] [Indexed: 12/14/2022] Open
Abstract
Bacillus thuringiensis is a well-known biopesticide that has been used for more than 80 years. This spore-forming bacterium belongs to the group of Bacillus cereus that also includes, among others, emetic and diarrheic pathotypes of B. cereus, the animal pathogen Bacillus anthracis and the psychrotolerant Bacillus weihenstephanensis. Bacillus thuringiensis is rather unique since it has adapted its lifestyle as an efficient pathogen of specific insect larvae. One of the peculiarities of B. thuringiensis strains is the extent of their extrachromosomal pool, with strains harbouring more than 10 distinct plasmid molecules. Among the numerous serovars of B. thuringiensis, 'israelensis' is certainly emblematic since its host spectrum is apparently restricted to dipteran insects like mosquitoes and black flies, vectors of human and animal diseases such as malaria, yellow fever, or river blindness. In this review, the putative role of the mobile gene pool of B. thuringiensis serovar israelensis in its pathogenicity and dedicated lifestyle is reviewed, with specific emphasis on the nature, diversity, and potential mobility of its constituents. Variations among the few related strains of B. thuringiensis serovar israelensis will also be reported and discussed in the scope of this specialised insect pathogen, whose lifestyle in the environment remains largely unknown.
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Affiliation(s)
- Annika Gillis
- Laboratory of Food and Environmental Microbiology, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Nancy Fayad
- Laboratory of Food and Environmental Microbiology, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
- Laboratory of Biodiversity and Functional Genomics (BGF), Faculty of Sciences, Université Saint-Joseph, 1107 2050 Beirut, Lebanon
| | - Lionel Makart
- Laboratory of Food and Environmental Microbiology, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Alexander Bolotin
- UMR1319 Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, F-78350 Jouy-en-Josas, France
| | - Alexei Sorokin
- UMR1319 Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, F-78350 Jouy-en-Josas, France
| | - Mireille Kallassy
- Laboratory of Biodiversity and Functional Genomics (BGF), Faculty of Sciences, Université Saint-Joseph, 1107 2050 Beirut, Lebanon
| | - Jacques Mahillon
- Laboratory of Food and Environmental Microbiology, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
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254
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Dominant point mutation in a tetraspanin gene associated with field-evolved resistance of cotton bollworm to transgenic Bt cotton. Proc Natl Acad Sci U S A 2018; 115:11760-11765. [PMID: 30381456 DOI: 10.1073/pnas.1812138115] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Extensive planting of crops genetically engineered to produce insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) has suppressed some major pests, reduced insecticide sprays, enhanced pest control by natural enemies, and increased grower profits. However, rapid evolution of resistance in pests is reducing these benefits. Better understanding of the genetic basis of resistance to Bt crops is urgently needed to monitor, delay, and counter pest resistance. We discovered that a point mutation in a previously unknown tetraspanin gene in the cotton bollworm (Helicoverpa armigera), a devastating global pest, confers dominant resistance to Cry1Ac, the sole Bt protein produced by transgenic cotton planted in China. We found the mutation using a genome-wide association study, followed by fine-scale genetic mapping and DNA sequence comparisons between resistant and susceptible strains. CRISPR/Cas9 knockout of the tetraspanin gene restored susceptibility to a resistant strain, whereas inserting the mutation conferred 125-fold resistance in a susceptible strain. DNA screening of moths captured from 23 field sites in six provinces of northern China revealed a 100-fold increase in the frequency of this mutation, from 0.001 in 2006 to 0.10 in 2016. The correspondence between the observed trajectory of the mutation and the trajectory predicted from simulation modeling shows that the dominance of the mutation accelerated adaptation. Proactive identification and tracking of the tetraspanin mutation demonstrate the potential for genomic analysis, gene editing, and molecular monitoring to improve management of resistance.
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255
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Xu C, Cheng J, Lin H, Lin C, Gao J, Shen Z. Characterization of transgenic rice expressing fusion protein Cry1Ab/Vip3A for insect resistance. Sci Rep 2018; 8:15788. [PMID: 30361672 PMCID: PMC6202352 DOI: 10.1038/s41598-018-34104-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 09/13/2018] [Indexed: 01/16/2023] Open
Abstract
Management of resistance development of insect pests is of great importance for continued utilization of Bt crop. The high-dose/refuge and pyramid (gene stacking) strategy are commonly employed to delay the evolution of insect resistance. Due to the anticipated difficulty for deployment of mandatory refuge for transgenic crops in China, where the size of farmer is quite small, stacking of genes with different modes of action is a more feasible strategy. Here we report the development of transgenic rice expressing a fusion protein of Cry1Ab and Vip3A toxin. Analysis of trypsin proteolysis suggested that the fusion protein is equivalent to the combination of Cry1Ab and Vip3A protein. The transgenic plants expressing the fusion protein were found to be highly resistant to two major rice pests, Asiatic rice borer Chilo suppressalis (Lepidoptera: Crambidae) and rice leaf folder Cnaphalocrocis medinalis (Lepidoptera: Crambidae), while their agronomic performances showed no significant difference compared to the non-transgenic recipient rice. Therefore, the transgenic rice may be utilized for rice pest control in China.
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Affiliation(s)
- Chao Xu
- State Key Laboratory of Rice Biology, Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Jiahui Cheng
- State Key Laboratory of Rice Biology, Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Haiyan Lin
- State Key Laboratory of Rice Biology, Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Chaoyang Lin
- State Key Laboratory of Rice Biology, Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Jianhua Gao
- College of Life Science, Shanxi Agricultural University, Taigu, China
| | - Zhicheng Shen
- State Key Laboratory of Rice Biology, Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.
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256
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Florez AM, Suarez-Barrera MO, Morales GM, Rivera KV, Orduz S, Ochoa R, Guerra D, Muskus C. Toxic Activity, Molecular Modeling and Docking Simulations of Bacillus thuringiensis Cry11 Toxin Variants Obtained via DNA Shuffling. Front Microbiol 2018; 9:2461. [PMID: 30386315 PMCID: PMC6199390 DOI: 10.3389/fmicb.2018.02461] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 09/25/2018] [Indexed: 11/23/2022] Open
Abstract
The Cry11 family belongs to a large group of δ-endotoxins that share three distinct structural domains. Among the dipteran-active toxins referred to as three-domain Cry11 toxins, the Cry11Aa protein from Bacillus thuringiensis subsp. israelensis (Bti) has been the most extensively studied. Despite the potential of Bti as an effective biological control agent, the understanding of Cry11 toxins remains incomplete. In this study, five Cry11 variants obtained via DNA shuffling displayed toxic activity against Aedes aegypti and Culex quinquefasciatus. Three of these Cry11 variants (8, 23, and 79) were characterized via 3D modeling and analysis of docking with ALP1. The relevant mutations in these variants, such as deletions, insertions and point mutations, are discussed in relation to their structural domains, toxic activities and toxin-receptor interactions. Importantly, deletion of the N-terminal segment in domain I was not associated with any change in toxic activity, and domain III exhibited higher sequence variability than domains I and II. Variant 8 exhibited up to 3.78- and 6.09-fold higher toxicity to A. aegypti than Cry11Bb and Cry11Aa, respectively. Importantly, variant 79 showed an α-helix conformation at the C-terminus and formed crystals retaining toxic activity. These findings indicate that five Cry11 variants were preferentially reassembled from the cry11Aa gene during DNA shuffling. The mutations described in loop 2 and loop 3 of domain II provide valuable information regarding the activity of Cry11 toxins against A. aegypti and C. quinquefasciatus larvae and reveal new insights into the application of directed evolution strategies to study the genetic variability of specific domains in cry11 family genes.
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Affiliation(s)
- Alvaro Mauricio Florez
- RG Microbial Ecology: Metabolism, Genomics & Evolution, Microbiomas Foundation, Chía, Colombia
| | - Miguel Orlando Suarez-Barrera
- Laboratorio de Biología Molecular y Biotecnología, Universidad de Santander, Bucaramanga, Colombia.,Escuela de Medicina, Facultad de Salud, Universidad Industrial de Santander, Bucaramanga, Colombia
| | - Gloria M Morales
- Laboratorio de Biología Molecular y Biotecnología, Universidad de Santander, Bucaramanga, Colombia
| | - Karen Viviana Rivera
- Laboratorio de Biología Molecular y Biotecnología, Universidad de Santander, Bucaramanga, Colombia
| | - Sergio Orduz
- Grupo Biologa Funcional, Laboratorio de Prospección y Diseo de Biomoléculas, Escuela de Biociencias, Universidad Nacional, Sede Medellín, Colombia
| | - Rodrigo Ochoa
- Programa de Estudio y Control de Enfermedades Tropicales PECET, Unidad de Biologa Molecular y Computacional-UBMC, Universidad de Antioquía, Medellín, Colombia
| | - Diego Guerra
- Programa de Estudio y Control de Enfermedades Tropicales PECET, Unidad de Biologa Molecular y Computacional-UBMC, Universidad de Antioquía, Medellín, Colombia
| | - Carlos Muskus
- Programa de Estudio y Control de Enfermedades Tropicales PECET, Unidad de Biologa Molecular y Computacional-UBMC, Universidad de Antioquía, Medellín, Colombia
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257
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Daas MS, Rosana ARR, Acedo JZ, Douzane M, Nateche F, Kebbouche-Gana S, Vederas JC. Insights into the draft genome sequence of bioactives-producing Bacillus thuringiensis DNG9 isolated from Algerian soil-oil slough. Stand Genomic Sci 2018; 13:25. [PMID: 30344888 PMCID: PMC6186030 DOI: 10.1186/s40793-018-0331-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 09/28/2018] [Indexed: 12/16/2022] Open
Abstract
Bacillus thuringiensis is widely used as a bioinsecticide due to its ability to form parasporal crystals containing proteinaceous toxins. It is a member of the Bacillus cereus sensu lato, a group with low genetic diversity but produces several promising antimicrobial compounds. B. thuringiensis DNG9, isolated from an oil-contaminated slough in Algeria, has strong antibacterial, antifungal and biosurfactant properties. Here, we report the 6.06 Mbp draft genome sequence of B. thuringiensis DNG9. The genome encodes several gene inventories for the biosynthesis of bioactive compounds such as zwittermycin A, petrobactin, insecticidal toxins, polyhydroxyalkanoates and multiple bacteriocins. We expect the genome information of strain DNG9 will provide another model system to study pathogenicity against insect pests, plant diseases, and antimicrobial compound mining and comparative phylogenesis among the Bacillus cereus sensu lato group.
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Affiliation(s)
- Mohamed Seghir Daas
- Valcore Laboratory, Department of Biology, University M’Hamed Bougara of Boumerdes, 35000 Boumerdes, Algeria
- Food Technology Research Division, Institut National de la Recherche Agronomique d’Algérie, 16200, El Harrach, Algiers, Algeria
| | | | - Jeella Z. Acedo
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2 Canada
| | - Malika Douzane
- Food Technology Research Division, Institut National de la Recherche Agronomique d’Algérie, 16200, El Harrach, Algiers, Algeria
| | - Farida Nateche
- Microbiology Group, Laboratory of Cellular and Molecular Biology, Faculty of Biological Sciences, University of Science and Technology–Houari Boumediene, 16111, Bab Ezzouar, Algiers, Algeria
| | - Salima Kebbouche-Gana
- Valcore Laboratory, Department of Biology, University M’Hamed Bougara of Boumerdes, 35000 Boumerdes, Algeria
| | - John C. Vederas
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2 Canada
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258
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Scavenger receptor-C acts as a receptor for Bacillus thuringiensis vegetative insecticidal protein Vip3Aa and mediates the internalization of Vip3Aa via endocytosis. PLoS Pathog 2018; 14:e1007347. [PMID: 30286203 PMCID: PMC6191154 DOI: 10.1371/journal.ppat.1007347] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 10/16/2018] [Accepted: 09/19/2018] [Indexed: 12/13/2022] Open
Abstract
The vegetative insecticidal proteins (Vip), secreted by many Bacillus thuringiensis strains during their vegetative growth stage, are genetically distinct from known insecticidal crystal proteins (ICPs) and represent the second-generation insecticidal toxins. Compared with ICPs, the insecticidal mechanisms of Vip toxins are poorly understood. In particular, there has been no report of a definite receptor of Vip toxins to date. In the present study, we identified the scavenger receptor class C like protein (Sf-SR-C) from the Spodoptera frugiperda (Sf9) cells membrane proteins that bind to the biotin labeled Vip3Aa, via the affinity magnetic bead method coupled with HPLC-MS/MS. We then certified Vip3Aa protoxin could interact with Sf-SR-C in vitro and ex vivo. In addition, downregulation of SR-C expression in Sf9 cells and Spodoptera exigua larvae midgut reduced the toxicity of Vip3Aa to them. Coincidently, heterologous expression of Sf-SR-C in transgenic Drosophila midgut significantly enhanced the virulence of Vip3Aa to the Drosophila larvae. Moreover, the complement control protein domain and MAM domain of Sf-SR-C are involved in the interaction with Vip3Aa protoxin. Furthermore, endocytosis of Vip3Aa mediated by Sf-SR-C correlates with its insecticidal activity. Our results confirmed for the first time that Sf-SR-C acts as a receptor for Vip3Aa protoxin and provides an insight into the mode of action of Vip3Aa that will significantly facilitate the study of its insecticidal mechanism and application. Bacillus thuringiensis Vip3A has potential in control of Lepidopteran pest and has been used in transgenic plants. However, studies of the insecticidal mechanisms of Vip3A are rare, and none of their definite receptors have been reported so far, which seriously restricts the study of its insecticidal mechanism and application. This work identified and confirmed the scavenger receptor class C like protein (Sf-SR-C) acts as the receptor of Vip3Aa protoxin, demonstrated that Sf-SR-C mediates the toxicity of Vip3Aa to Sf9 cells in an internalized manner. These results extend our understanding of SR-C proteins in insects and explain the specificity of Vip3Aa insecticidal activity, which strongly support it as a safe biopesticide. More importantly, it suggests the insecticidal mechanism of Vip3Aa different from the well-known “pore formation” model, “signal transduction” model, as well as newly found “necrosis” model of Cry toxins, which will significantly promote the relevant study of Vip3Aa. Last but not least, because scavenger receptors play a crucial role in innate immunity, our results provide relevant insights into host-pathogen interactions.
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259
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Martínez-Solís M, Pinos D, Endo H, Portugal L, Sato R, Ferré J, Herrero S, Hernández-Martínez P. Role of Bacillus thuringiensis Cry1A toxins domains in the binding to the ABCC2 receptor from Spodoptera exigua. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 101:47-56. [PMID: 30077769 DOI: 10.1016/j.ibmb.2018.07.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 07/24/2018] [Accepted: 07/29/2018] [Indexed: 06/08/2023]
Abstract
Cry proteins from Bacillus thuringiensis (Bt) have been used to control insect pests either as formulated sprays or as in Bt-crops. However, field-evolved resistance to Bt proteins is threatening the long-term use of Bt products. The SeABCC2 locus has been genetically linked to resistance to a Bt bioinsecticide (Xentari™) in Spodoptera exigua (a mutation producing a truncated form of the transporter lacking an ATP binding domain was found in the resistant insects). Here, we investigated the role of SeABCC2 in the mode of action of Cry1Aa, Cry1Ab, Cry1Ac, Cry1Ca, and two Cry1A-1Ca hybrids by expressing the receptor in Sf21 and HEK293T cell lines. Cell toxicity assays showed that Sf21 cells expressing SeABCC2 become susceptible to Cry1A proteins. HEK293T cells expressing the transporter were found susceptible to Cry1A proteins but not to Cry1Ca. The results with the Cry1A-1Ca hybrids suggest that domain II from Cry1Ab/c is crucial for the toxicity to Sf21 cells, whereas domain III from Cry1Aa/b is crucial for the toxicity to HEK293T cells. Binding assays showed that the Cry1Ac binding is of high affinity and specific to cells expressing the SeABCC2 transporter. Heterologous competition experiments support a model in which domain II of Cry1Ab/c has a common binding site in the SeABCC2 protein, whereas domain III of Cry1Aa/b binds to a different binding site in the SeABCC2 protein.
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Affiliation(s)
- María Martínez-Solís
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain
| | - Daniel Pinos
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain
| | - Haruka Endo
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
| | - Leivi Portugal
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Ryoichi Sato
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
| | - Juan Ferré
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain
| | - Salvador Herrero
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain
| | - Patricia Hernández-Martínez
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain.
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BIOINFORMATIC SEARCH OF CRISPR/CAS SYSTEM STRUCTURES IN GENOME OF PCT281 PLASMID OF BACILLUS THURINGIENSIS SUBSP. CHINENSIS STRAIN CT-43. ACTA BIOMEDICA SCIENTIFICA 2018. [DOI: 10.29413/abs.2018-3.5.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Background. CRISPR/Cas systems loci are one of the functionally important patterns in bacterial genome which perform the role of “adaptive immune defense” from foreign nucleic acids. The study of CRISPR/Cas systems structure in genomes of plasmids and phages provide new information about the evolution of this systems in bacterial hosts.Aims. A search of CRISPR/Cas systems structures in pCT281 plasmid from Bacillus thuringiensis subsp. chinensis strain CT-43 using bioinformatic methods.Materials and methods. Search studies using bioinformatics methods were performed with the genome of pCT281 plasmid of B. thuringiensis subsp. chinensis strain CT-43 from the RefSeq database. To search for the CRISPR/Cas system structure MacSyFinder (ver. 1.0.5) and three combined algorithms were used: CRISPRFinder; PILER-CR; CRISPR Recognition Tool (CRT). The consensus repeat sequence was generated in WebLogo 3.Results and discussion. In pCT281 plasmid we detected one locus of CRISPR/Cas system of the type I-C which contains 2 CRISPR-cassettes and 4 cas-genes located between them. The CRISPR-cassette 1 includes 10 spacers from 32 to 35 bp and 11 repeats 32bp in length. 5 spacers (33–35 bp) separated by 6 repeats 32 bp in length were detected in the CRISPR-cassette 2.Conclusions. The bioinformatic methods used in this study enable to conduct a search of CRISPR/Cas systems structures in plasmid genomes. The presence of the CRISPR-Cas locus in pCT281 plasmid confirms a possible transfer of this system from the nucleoid to this plasmid. The detected spacers provide information about phages this bacteria was encountered.
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261
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ABC transporter mis-splicing associated with resistance to Bt toxin Cry2Ab in laboratory- and field-selected pink bollworm. Sci Rep 2018; 8:13531. [PMID: 30202031 PMCID: PMC6131251 DOI: 10.1038/s41598-018-31840-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 08/28/2018] [Indexed: 11/13/2022] Open
Abstract
Evolution of pest resistance threatens the benefits of genetically engineered crops that produce Bacillus thuringiensis (Bt) insecticidal proteins. Strategies intended to delay pest resistance are most effective when implemented proactively. Accordingly, researchers have selected for and analyzed resistance to Bt toxins in many laboratory strains of pests before resistance evolves in the field, but the utility of this approach depends on the largely untested assumption that laboratory- and field-selected resistance to Bt toxins are similar. Here we compared the genetic basis of resistance to Bt toxin Cry2Ab, which is widely deployed in transgenic crops, between laboratory- and field-selected populations of the pink bollworm (Pectinophora gossypiella), a global pest of cotton. We discovered that resistance to Cry2Ab is associated with mutations disrupting the same ATP-binding cassette transporter gene (PgABCA2) in a laboratory-selected strain from Arizona, USA, and in field-selected populations from India. The most common mutation, loss of exon 6 caused by alternative splicing, occurred in resistant larvae from both locations. Together with previous data, the results imply that mutations in the same gene confer Bt resistance in laboratory- and field-selected strains and suggest that focusing on ABCA2 genes may help to accelerate progress in monitoring and managing resistance to Cry2Ab.
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262
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Liu L, Chen Z, Yang Y, Xiao Y, Liu C, Ma Y, Soberón M, Bravo A, Yang Y, Liu K. A single amino acid polymorphism in ABCC2 loop 1 is responsible for differential toxicity of Bacillus thuringiensis Cry1Ac toxin in different Spodoptera (Noctuidae) species. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 100:59-65. [PMID: 29964167 DOI: 10.1016/j.ibmb.2018.06.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 06/13/2018] [Accepted: 06/22/2018] [Indexed: 06/08/2023]
Abstract
Bacillus thuringiensis Cry toxins exert their toxicity by forming membrane pores after binding with larval midgut membrane proteins known as receptors. Spodoptera litura and Spodoptera frugiperda belong to the same genus, but S. litura is tolerant to Cry1Ac, while S. frugiperda is susceptible. The mechanism involved in the differential toxicity of Cry1Ac to these insect species is not understood. Amino acid sequences analysis of ABCC2, a well-recognized Cry1Ac receptor, from both species showed high sequence identity. Hi5 insect cells expressing SfABCC2 from S. frugiperda were 65-fold more susceptible than those expressing the SlABCC2 from S. litura. Substitution of fragments, point mutations and deletions between the ABCC2 of the two species revealed that ABCC2 amino acid Q125 from SfABCC2 or E125 from SlABCC2 was key factor for the differential Cry1Ac toxicity to Hi5 cells expressing these receptors. Consistently with this, cells expressing Helicoverpa armigera HaABCC2Q122-GFP, were more susceptible to Cry1Ac than cells expressing HaABCC2E122-GFP mutant. Q125 or E125 is located in a predicted exposed loop 1 region of ABCC2 indicating that this region could be important for Cry1Ac binding. These findings identified a single amino acid residue located in loop 1 of ABCC2 transporter as responsible for the different levels of susceptibility to Cry1Ac among various lepidopteran species.
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Affiliation(s)
- Leilei Liu
- Institute of Entomology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Zuwen Chen
- Institute of Entomology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Yanchao Yang
- Institute of Entomology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Yutao Xiao
- Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
| | - Chenxi Liu
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Chinese Academy of Agricultural Sciences, West Yuanmingyuan Road, Beijing, 100193, China
| | - Yuemin Ma
- Institute of Entomology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Mario Soberón
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, 62250, Morelos, Mexico
| | - Alejandra Bravo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, 62250, Morelos, Mexico.
| | - Yongbo Yang
- Institute of Entomology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.
| | - Kaiyu Liu
- Institute of Entomology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.
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263
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Determination of mosquito Larvicidal potential of Bacillus thuringiensis Cry11Ba fusion protein through molecular docking. Biologia (Bratisl) 2018. [DOI: 10.2478/s11756-018-0103-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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264
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Wei J, Liang G, Wu K, Gu S, Guo Y, Ni X, Li X. Cytotoxicity and binding profiles of activated Cry1Ac and Cry2Ab to three insect cell lines. INSECT SCIENCE 2018; 25:655-666. [PMID: 28247982 DOI: 10.1111/1744-7917.12451] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 11/24/2016] [Accepted: 01/03/2017] [Indexed: 06/06/2023]
Abstract
While Cry1Ac has been known to bind with larval midgut proteins cadherin, APN (amino peptidase N), ALP (alkaline phosphatase) and ABCC2 (adenosine triphosphate-binding cassette transporter subfamily C2), little is known about the receptors of Cry2Ab. To provide a clue to the receptors of Cry2Ab, we tested the baseline cytotoxicity of activated Cry1Ac and Cry2Ab against the midgut and fat body cell lines of Helicoverpa zea and the ovary cell line of Spodoptera frugiperda (SF9). As expected, the descending order of cytotoxicity of Cry1Ac against the three cell lines in terms of 50% lethal concetration (LC50 ) was midgut (31.0 μg/mL) > fat body (59.0 μg/mL) and SF9 cell (99.6 μg/mL). By contrast, the fat body cell line (LC50 = 7.55 μg/mL) was about twice more susceptible to Cry2Ab than the midgut cell line (16.0 μg/mL), the susceptibility of which was not significantly greater than that of SF9 cells (27.0 μg/mL). Further, ligand blot showed the binding differences between Cry1Ac and Cry2Ab in the three cell lines. These results indicated that the receptors of Cry2Ab were enriched in fat body cells and thus largely different from the receptors of Cry1Ac, which were enriched in midgut cells.
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Affiliation(s)
- Jizhen Wei
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Department of Entomology and BIO5 Institute, University of Arizona, Tucson, AZ, USA
| | - Gemei Liang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Kongming Wu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shaohua Gu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yuyuan Guo
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xinzhi Ni
- USDA-ARS, Crop Genetics and Breeding Research Unit, Tifton, GA, USA
| | - Xianchun Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Department of Entomology and BIO5 Institute, University of Arizona, Tucson, AZ, USA
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265
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Helix α-3 inter-molecular salt bridges and conformational changes are essential for toxicity of Bacillus thuringiensis 3D-Cry toxin family. Sci Rep 2018; 8:10331. [PMID: 29985464 PMCID: PMC6037675 DOI: 10.1038/s41598-018-28753-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 06/29/2018] [Indexed: 12/31/2022] Open
Abstract
Bacillus thuringiensis insecticidal Cry toxins break down larval midgut-cells after forming pores. The 3D-structures of Cry4Ba and Cry5Ba revealed a trimeric-oligomer after cleavage of helices α-1 and α-2a, where helix α-3 is extended and made contacts with adjacent monomers. Molecular dynamic simulations of Cry1Ab-oligomer model based on Cry4Ba-coordinates showed that E101 forms a salt-bridge with R99 from neighbor monomer. An additional salt bridge was identified in the trimeric-Cry5Ba, located at the extended helix α-3 in the region corresponding to the α-2b and α-3 loop. Both salt-bridges were analyzed by site directed mutagenesis. Single-point mutations in the Lepidoptera-specific Cry1Ab and Cry1Fa toxins were affected in toxicity, while reversed double-point mutant partially recovered the phenotype, consistent with a critical role of these salt-bridges. The single-point mutations in the salt-bridge at the extended helix α-3 of the nematicidal Cry5Ba were also non-toxic. The incorporation of this additional salt bridge into the nontoxic Cry1Ab-R99E mutant partially restored oligomerization and toxicity, supporting that the loop between α-2b and α-3 forms part of an extended helix α-3 upon oligomerization of Cry1 toxins. Overall, these results highlight the role in toxicity of salt-bridge formation between helices α-3 of adjacent monomers supporting a conformational change in helix α-3.
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266
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Whole-Genome Analysis of Bacillus thuringiensis Revealing Partial Genes as a Source of Novel Cry Toxins. Appl Environ Microbiol 2018; 84:AEM.00277-18. [PMID: 29752275 DOI: 10.1128/aem.00277-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 05/05/2018] [Indexed: 12/20/2022] Open
Abstract
Despite the successful application of crystal proteins (Cry) from Bacillus thuringiensis as biological control agents against insects, there is an increasing demand to identify new Cry toxins having higher toxicity and broad-spectrum activity against insects and plant-parasitic nematodes. To find novel Cry toxins, we screened 100 whole-genome sequences of B. thuringiensis Surprisingly, in addition to full Cry toxins, we found partial sequences, such as typical N-terminal or C-terminal regions with conserved domains, widely distributed among 20 strains of B. thuringiensis In order to further elucidate the functions of partial genes, here, we selected a partial sequence from strain C15, having 28% similarity with the N terminus of Cry5Ba and lacking a typical C terminus, and denoted it Cry5B-like N terminus. This fragment when coexpressed as a fusion protein with the C terminus of Cry5Ba (N-C fusion protein) produces pyramidal crystals. A recombinant N-C fusion protein having a 50% lethal concentration (LC50) of 23.7 μg/ml severely affected the life span, growth, and survival rate of nematodes. Light microscopy showed damage to the intestine of nematodes, confirming the pathogenicity of the N-C fusion protein. Last, the green fluorescent protein (GFP)-labeled mutant Caenorhabditis elegans FT63 showed significant damage to the intestine upon feeding N-C fusion toxin compared to the control. These results imply that partial genes can be a source of new Cry toxins, and further understanding about functions of partial cry genes can help in the study of the evolutionary strategy of B. thuringiensis to produce the multidomain toxins.IMPORTANCE Genomic analysis revealed that coding sequences for N termini and C termini of crystal proteins are widely distributed in B. thuringiensis We found Cry5B-like N terminus, lacking typical C terminus, was unable to be expressed in wild-type strain C15. However, its fusion with the C terminus of Cry5Ba not only was successfully expressed but also exhibited activity against the nematodes. This study provides insight into a potential source for novel Cry toxins.
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267
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Rocha-Munive MG, Soberón M, Castañeda S, Niaves E, Scheinvar E, Eguiarte LE, Mota-Sánchez D, Rosales-Robles E, Nava-Camberos U, Martínez-Carrillo JL, Blanco CA, Bravo A, Souza V. Evaluation of the Impact of Genetically Modified Cotton After 20 Years of Cultivation in Mexico. Front Bioeng Biotechnol 2018; 6:82. [PMID: 29988354 PMCID: PMC6023983 DOI: 10.3389/fbioe.2018.00082] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/31/2018] [Indexed: 11/16/2022] Open
Abstract
For more than 20 years cotton has been the most widely sown genetically modified (GM) crop in Mexico. Its cultivation has fulfilled all requirements and has gone through the different regulatory stages. During the last 20 years, both research-institutions and biotech-companies have generated scientific and technical information regarding GM cotton cultivation in Mexico. In this work, we collected data in order to analyze the environmental and agronomic effects of the use of GM cotton in Mexico. In 1996, the introduction of Bt cotton made it possible to reactivate this crop, which in previous years was greatly reduced due to pest problems, production costs and environmental concerns. Bt cotton is a widely accepted tool for cotton producers and has proven to be efficient for the control of lepidopteran pests. The economic benefits of its use are variable, and depend on factors such as the international cotton-prices and other costs associated with its inputs. So far, the management strategies used to prevent development of insect resistance to GM cotton has been successful, and there are no reports of insect resistance development to Bt cotton in Mexico. In addition, no effects have been observed on non-target organisms. For herbicide tolerant cotton, the prevention of herbicide resistance has also been successful since unlike other countries, the onset of resistance weeds is still slow, apparently due to cultural practices and rotation of different herbicides. Environmental benefits have been achieved with a reduction in chemical insecticide applications and the subsequent decrease in primary pest populations, so that the inclusion of other technologies—e.g., use of non-Bt cotton- can be explored. Nevertheless, control measures need to be implemented during transport of the bolls and fiber to prevent dispersal of volunteer plants and subsequent gene flow to wild relatives distributed outside the GM cotton growing areas. It is still necessary to implement national research programs, so that biotechnology and plant breeding advances can be used in the development of cotton varieties adapted to the Mexican particular environmental conditions and to control insect pests of regional importance.
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Affiliation(s)
- Martha G Rocha-Munive
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Mario Soberón
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Saúl Castañeda
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Esteban Niaves
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Enrique Scheinvar
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Luis E Eguiarte
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - David Mota-Sánchez
- Department of Entomology, Michigan State University, East Lansing, MI, United States
| | | | - Urbano Nava-Camberos
- Facultad de Agricultura y Zootecnia/Facultad de Ciencias Biológicas, Universidad Juárez del Estado de Durango, Gómez Palacio, Mexico
| | | | - Carlos A Blanco
- Biology Department, University of New Mexico, Albuquerque, NM, United States
| | - Alejandra Bravo
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Valeria Souza
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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268
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Chen L, Wei J, Liu C, Zhang W, Wang B, Niu L, Liang G. Specific Binding Protein ABCC1 Is Associated With Cry2Ab Toxicity in Helicoverpa armigera. Front Physiol 2018; 9:745. [PMID: 29971014 PMCID: PMC6018205 DOI: 10.3389/fphys.2018.00745] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 05/28/2018] [Indexed: 01/10/2023] Open
Abstract
A pyramid strategy combining the crystal (Cry) 1A and 2A toxins in Bacillus thuringiensis (Bt) crops are active against many species of insects and nematode larvae. It has been widely used to delay pest adaption to genetically modified plants and broaden the insecticidal spectrum in many countries. Unfortunately, Cry2A can also bind with the specific receptor proteins of Cry1A. ATP-binding cassette (ABC) transporters can interact with Cry1A toxins as receptors in the insect midgut, and ABC transporter mutations result in resistance to Bt proteins. However, there is limited knowledge of the ABC transporters that specifically bind to Cry2Ab. Here, we cloned the ABCC1 gene in Helicoverpa armigera, which expressed at all larval stages and in nine different tissues. Expression levels were particularly high in fifth-instar larvae and Malpighian tubules. The two heterologously expressed HaABCC1 transmembrane domain peptides could specifically bind to Cry2Ab with high affinity levels. Moreover, transfecting HaABCC1 into the Spodoptera frugiperda nine insect cell significantly increased its mortality when exposed to Cry2Ab in vitro, and silencing HaABCC1 in H. armigera by RNA interference significantly reduced the mortality of larvae exposed to Cry2Ab in vivo. Altogether current results suggest that HaABCC1 serves as a functional receptor for Cry2Ab.
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Affiliation(s)
- Lin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jizhen Wei
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Chen Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Wanna Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Bingjie Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - LinLin Niu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Gemei Liang
- 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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269
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Gao M, Wang X, Yang Y, Tabashnik BE, Wu Y. Epistasis confers resistance to Bt toxin Cry1Ac in the cotton bollworm. Evol Appl 2018; 11:809-819. [PMID: 29875821 PMCID: PMC5979638 DOI: 10.1111/eva.12598] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 01/10/2018] [Indexed: 01/06/2023] Open
Abstract
Evolution of resistance by insect pests reduces the benefits of extensively cultivated transgenic crops that produce insecticidal proteins from Bacillus thuringiensis (Bt). Previous work showed that resistance to Bt toxin Cry1Ac, which is produced by transgenic cotton, can be conferred by mutations disrupting a cadherin protein that binds this Bt toxin in the larval midgut. However, the potential for epistatic interactions between the cadherin gene and other genes has received little attention. Here, we report evidence of epistasis conferring resistance to Cry1Ac in the cotton bollworm, Helicoverpa armigera, one of the world's most devastating crop pests. Resistance to Cry1Ac in strain LF256 originated from a field-captured male and was autosomal, recessive, and 220-fold relative to susceptible strain SCD. We conducted complementation tests for allelism by crossing LF256 with a strain in which resistance to Cry1Ac is conferred by a recessive allele at the cadherin locus HaCad. The resulting F1 offspring were resistant, suggesting that resistance to Cry1Ac in LF256 is also conferred by resistance alleles at this locus. However, the HaCad amino acid sequence in LF256 lacked insertions and deletions, and did not differ consistently between LF256 and a susceptible strain. In addition, most of the cadherin alleles in LF256 were not derived from the field-captured male. Moreover, Cry1Ac resistance was not genetically linked with the HaCad locus in LF256. Furthermore, LF256 and the susceptible strain were similar in levels of HaCad transcript, cadherin protein, and binding of Cry1Ac to cadherin. Overall, the results imply that epistasis between HaCad and an unknown second locus in LF256 yielded the observed resistance in the F1 progeny from the complementation test. The observed epistasis has important implications for interpreting results of the F1 screen used widely to monitor and analyze resistance, as well as the potential to accelerate evolution of resistance.
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Affiliation(s)
- Meijing Gao
- College of Plant ProtectionNanjing Agricultural UniversityNanjingChina
| | - Ximeng Wang
- College of Plant ProtectionNanjing Agricultural UniversityNanjingChina
| | - Yihua Yang
- College of Plant ProtectionNanjing Agricultural UniversityNanjingChina
| | | | - Yidong Wu
- College of Plant ProtectionNanjing Agricultural UniversityNanjingChina
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270
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Expression of hybrid fusion protein (Cry1Ac::ASAL) in transgenic rice plants imparts resistance against multiple insect pests. Sci Rep 2018; 8:8458. [PMID: 29855556 PMCID: PMC5981619 DOI: 10.1038/s41598-018-26881-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 05/21/2018] [Indexed: 12/18/2022] Open
Abstract
To evolve rice varieties resistant to different groups of insect pests a fusion gene, comprising DI and DII domains of Bt Cry1Ac and carbohydrate binding domain of garlic lectin (ASAL), was constructed. Transgenic rice lines were generated and evaluated to assess the efficacy of Cry1Ac::ASAL fusion protein against three major pests, viz., yellow stem borer (YSB), leaf folder (LF) and brown planthopper (BPH). Molecular analyses of transgenic plants revealed stable integration and expression of the fusion gene. In planta insect bioassays on transgenics disclosed enhanced levels of resistance compared to the control plants. High insect mortality of YSB, LF and BPH was observed on transgenics compared to that of control plants. Furthermore, honeydew assays revealed significant decreases in the feeding ability of BPH on transgenic plants as compared to the controls. Ligand blot analysis, using BPH insects fed on cry1Ac::asal transgenic rice plants, revealed a modified receptor protein-binding pattern owing to its ability to bind to additional receptors in insects. The overall results authenticate that Cry1Ac::ASAL protein is endowed with remarkable entomotoxic effects against major lepidopteran and hemipteran insects. As such, the fusion gene appears promising and can be introduced into various other crops to control multiple insect pests.
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271
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Silva-Brandão KL, Peruchi A, Seraphim N, Murad NF, Carvalho RA, Farias JR, Omoto C, Cônsoli FL, Figueira A, Brandão MM. Loci under selection and markers associated with host plant and host-related strains shape the genetic structure of Brazilian populations of Spodoptera frugiperda (Lepidoptera, Noctuidae). PLoS One 2018; 13:e0197378. [PMID: 29787608 PMCID: PMC5963752 DOI: 10.1371/journal.pone.0197378] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 05/01/2018] [Indexed: 11/18/2022] Open
Abstract
We applied the ddRAD genotyping-by-sequencing technique to investigate the genetic distinctiveness of Brazilian populations of the noctuid moth Spodoptera frugiperda, the fall armyworm (FAW), and the role of host-plant association as a source of genetic diversification. By strain-genotyping all field-collected individuals we found that populations collected from corn were composed primarily of corn-strain individuals, while the population collected from rice was composed almost entirely of rice-strain individuals. Outlier analyses indicated 1,184 loci putatively under selection (ca. 15% of the total) related to 194 different Gene Ontologies (GOs); the most numerous GOs were nucleotide binding, ATP binding, metal-ion binding and nucleic-acid binding. The association analyses indicated 326 loci associated with the host plant, and 216 loci associated with the individual strain, including functions related to Bacillus thuringiensis and insecticide resistance. The genetic-structure analyses indicated a moderate level of differentiation among all populations, and lower genetic structure among populations collected exclusively from corn, which suggests that the population collected from rice has a strong influence on the overall genetic structure. Populations of S. frugiperda are structured partially due to the host plant, and pairs of populations using the same host plant are more genetically similar than pairs using different hosts. Loci putatively under selection are the main factors responsible for the genetic structure of these populations, which indicates that adaptive selection on important traits, including the response to control tactics, is acting in the genetic differentiation of FAW populations in Brazil.
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Affiliation(s)
- Karina Lucas Silva-Brandão
- Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Campus "Luiz de Queiroz", Laboratório de Melhoramento de Plantas, Piracicaba, São Paulo, Brazil
- * E-mail:
| | - Aline Peruchi
- Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Campus "Luiz de Queiroz", Laboratório de Melhoramento de Plantas, Piracicaba, São Paulo, Brazil
| | - Noemy Seraphim
- Instituto Federal de Educação, Ciência e Tecnologia de São Paulo, campus Campinas CTI Renato Archer, Campinas, São Paulo, Brazil
| | - Natália Faraj Murad
- Programa de Pós-graduação em Genética e Biologia Molecular, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil
| | | | - Juliano Ricardo Farias
- Instituto Phytus, Departamento de Entomologia, Rua Duque de Caxias, Santa Maria, Rio Grande do Sul, Brazil
| | - Celso Omoto
- Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo, Departamento de Entomologia e Acarologia, Piracicaba, São Paulo, Brazil
| | - Fernando Luis Cônsoli
- Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo, Departamento de Entomologia e Acarologia, Piracicaba, São Paulo, Brazil
| | - Antonio Figueira
- Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Campus "Luiz de Queiroz", Laboratório de Melhoramento de Plantas, Piracicaba, São Paulo, Brazil
| | - Marcelo Mendes Brandão
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil
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272
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Lourenço AM, Haddi K, Ribeiro BM, Corrêia RFT, Tomé HVV, Santos-Amaya O, Pereira EJG, Guedes RNC, Santos GR, Oliveira EE, Aguiar RWS. Essential oil of Siparuna guianensis as an alternative tool for improved lepidopteran control and resistance management practices. Sci Rep 2018; 8:7215. [PMID: 29740112 PMCID: PMC5940754 DOI: 10.1038/s41598-018-25721-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 04/06/2018] [Indexed: 11/09/2022] Open
Abstract
Although the cultivation of transgenic plants expressing toxins of Bacillus thuringiensis (Bt) represents a successful pest management strategy, the rapid evolution of resistance to Bt plants in several lepidopteran pests has threatened the sustainability of this practice. By exhibiting a favorable safety profile and allowing integration with pest management initiatives, plant essential oils have become relevant pest control alternatives. Here, we assessed the potential of essential oils extracted from a Neotropical plant, Siparuna guianensis Aublet, for improving the control and resistance management of key lepidopteran pests (i.e., Spodoptera frugiperda and Anticarsia gemmatalis). The essential oil exhibited high toxicity against both lepidopteran pest species (including an S. frugiperda strain resistant to Cry1A.105 and Cry2Ab Bt toxins). This high insecticidal activity was associated with necrotic and apoptotic effects revealed by in vitro assays with lepidopteran (but not human) cell lines. Furthermore, deficits in reproduction (e.g., egg-laying deterrence and decreased egg viability), larval development (e.g., feeding inhibition) and locomotion (e.g., individual and grouped larvae walking activities) were recorded for lepidopterans sublethally exposed to the essential oil. Thus, by similarly and efficiently controlling lepidopteran strains susceptible and resistant to Bt toxins, the S. guianensis essential oil represents a promising management tool against key lepidopteran pests.
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Affiliation(s)
- Adriano M Lourenço
- Departamento de Biotecnologia, Universidade Federal de Tocantins, Gurupi, TO, 77413-070, Brazil
| | - Khalid Haddi
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Bergman M Ribeiro
- Departamento de Biologia Celular, Universidade de Brasília, Brasilia, DF, 70910-900, Brazil
| | - Roberto F T Corrêia
- Departamento de Biotecnologia, Universidade Federal de Tocantins, Gurupi, TO, 77413-070, Brazil.,Departamento de Biologia Celular, Universidade de Brasília, Brasilia, DF, 70910-900, Brazil
| | - Hudson V V Tomé
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil.,EAG Laboratories, 13709 Progress Blvd #24 Suite S163, Alachua-FL, 32615, USA
| | - Oscar Santos-Amaya
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Eliseu J G Pereira
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Raul N C Guedes
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Gil R Santos
- Departamento de Biotecnologia, Universidade Federal de Tocantins, Gurupi, TO, 77413-070, Brazil
| | - Eugênio E Oliveira
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Raimundo W S Aguiar
- Departamento de Biotecnologia, Universidade Federal de Tocantins, Gurupi, TO, 77413-070, Brazil.
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Hu X, Zhang X, Zhong J, Liu Y, Zhang C, Xie Y, Lin M, Xu C, Lu L, Zhu Q, Liu X. Expression of Cry1Ac toxin-binding region in Plutella xyllostella cadherin-like receptor and studying their interaction mode by molecular docking and site-directed mutagenesis. Int J Biol Macromol 2018; 111:822-831. [DOI: 10.1016/j.ijbiomac.2017.12.135] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 12/15/2017] [Accepted: 12/25/2017] [Indexed: 01/16/2023]
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274
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Walters FS, Graser G, Burns A, Raybould A. When the Whole is Not Greater than the Sum of the Parts: A Critical Review of Laboratory Bioassay Effects Testing for Insecticidal Protein Interactions. ENVIRONMENTAL ENTOMOLOGY 2018; 47:484-497. [PMID: 29432611 PMCID: PMC5888968 DOI: 10.1093/ee/nvx207] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Many studies have been conducted to investigate synergism among insecticidal proteins; however, a consensus on minimal data requirements and interpretation is lacking. While some have concluded that all additive predictive-type models should be abandoned, we advocate that additivity models can remain useful as assessment tools and that an appropriately designed interaction study will never systematically underestimate the existence of synergism, irrespective of which additivity model (or none at all) may be used. To generate the most meaningful synergy assessment datasets in support of safety assessments, we highlight two beneficial steps to follow: (i) select a testing model which is the most consistent with current knowledge regarding the action of the insecticidal proteins and (ii) avoid using bioassay methods which may result in excess response heterogeneity. We also outline other experimental design elements to consider, which may be crucial for conducting future studies of this type. A contrast of underlying testing assumptions associated with the additivity models is provided, along with a comprehensive review of interaction data for Cry1, Cry2, Cry3, Cry9, and Vip3A insecticidal proteins. Our review captures four recurrent findings: i) experiments reporting synergistic interactions are a minority, ii) the degree of synergism reported is low in magnitude, iii) reported interactions are sometimes equivocal/inconclusive due to unconfirmed model assumptions or other bioassay challenges, and iv) due to biological response variation many of the reported interactions may be artefactual. A brief overview of the positioning of interaction testing data in safety assessments of GM food crops is also provided.
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Affiliation(s)
| | - Gerson Graser
- Syngenta Crop Protection, LLC, Davis Drive, Durham, NC, USA
| | - Andrea Burns
- Syngenta Crop Protection, LLC, Davis Drive, Durham, NC, USA
| | - Alan Raybould
- Syngenta Crop Protection AG, Schwarzwaldallee, Basel, Switzerl
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275
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Recent advancement on chemical arsenal of Bt toxin and its application in pest management system in agricultural field. 3 Biotech 2018; 8:201. [PMID: 29607282 DOI: 10.1007/s13205-018-1223-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Accepted: 03/22/2018] [Indexed: 10/17/2022] Open
Abstract
Bacillus thuringiensis (Bt) is a Gram-positive, spore-forming, soil bacterium, which is very popular bio-control agent in agricultural and forestry. In general, B. thuringiensis secretes an array of insecticidal proteins including toxins produced during vegetative growth phase (such as secreted insecticidal protein, Sip; vegetative insecticidal proteins, Vip), parasporal crystalline δ-endotoxins produced during vegetative stationary phase (such as cytolytic toxin, Cyt; and crystal toxin, Cry), and β-exotoxins. Till date, a wide spectrum of Cry proteins has been reported and most of them belong to three-domain-Cry toxins, Bin-like toxin, and Etx_Mtx2-like toxins. To the best of our knowledge, neither Bt insecticidal toxins are exclusive to Bt nor all the strains of Bt are capable of producing insecticidal Bt toxins. The lacuna in their latest classification has also been discussed. In this review, the updated information regarding the insecticidal Bt toxins and their different mode of actions were summarized. Before applying the Bt toxins on agricultural field, the non-specific effects of toxins should be investigated. We also have summarized the problem of insect resistance and the strategies to combat with this problem. We strongly believe that this information will help a lot to the budding researchers in the field of modern pest control biotechnology.
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276
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Torres-Quintero MC, Gómez I, Pacheco S, Sánchez J, Flores H, Osuna J, Mendoza G, Soberón M, Bravo A. Engineering Bacillus thuringiensis Cyt1Aa toxin specificity from dipteran to lepidopteran toxicity. Sci Rep 2018; 8:4989. [PMID: 29563565 PMCID: PMC5862903 DOI: 10.1038/s41598-018-22740-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 02/28/2018] [Indexed: 11/09/2022] Open
Abstract
The Cyt and Cry toxins are different pore-forming proteins produced by Bacillus thuringiensis bacteria, and used in insect-pests control. Cry-toxins have a complex mechanism involving interaction with several proteins in the insect gut such as aminopeptidase N (APN), alkaline phosphatase (ALP) and cadherin (CAD). It was shown that the loop regions of domain II of Cry toxins participate in receptor binding. Cyt-toxins are dipteran specific and interact with membrane lipids. We show that Cry1Ab domain II loop3 is involved in binding to APN, ALP and CAD receptors since point mutation Cry1Ab-G439D affected binding to these proteins. We hypothesized that construction of Cyt1A-hybrid proteins providing a binding site that recognizes gut proteins in lepidopteran larvae could result in improved Cyt1Aa toxin toward lepidopteran larvae. We constructed hybrid Cyt1Aa-loop3 proteins with increased binding interaction to Manduca sexta receptors and increased toxicity against two Lepidopteran pests, M. sexta and Plutella xylostella. The hybrid Cyt1Aa-loop3 proteins were severely affected in mosquitocidal activity and showed partial hemolytic activity but retained their capacity to synergize Cry11Aa toxicity against mosquitos. Our data show that insect specificity of Cyt1Aa toxin can be modified by introduction of loop regions from another non-related toxin with different insect specificity.
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Affiliation(s)
- Mary-Carmen Torres-Quintero
- Departamento de Microbiología, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. postal 510-3, Cuernavaca, 62250, Morelos, Mexico
| | - Isabel Gómez
- Departamento de Microbiología, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. postal 510-3, Cuernavaca, 62250, Morelos, Mexico
| | - Sabino Pacheco
- Departamento de Microbiología, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. postal 510-3, Cuernavaca, 62250, Morelos, Mexico
| | - Jorge Sánchez
- Departamento de Microbiología, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. postal 510-3, Cuernavaca, 62250, Morelos, Mexico
| | - Humberto Flores
- Departamento de Microbiología, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. postal 510-3, Cuernavaca, 62250, Morelos, Mexico
| | - Joel Osuna
- Departamento de Microbiología, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. postal 510-3, Cuernavaca, 62250, Morelos, Mexico
| | - Gretel Mendoza
- Departamento de Microbiología, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. postal 510-3, Cuernavaca, 62250, Morelos, Mexico
| | - Mario Soberón
- Departamento de Microbiología, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. postal 510-3, Cuernavaca, 62250, Morelos, Mexico
| | - Alejandra Bravo
- Departamento de Microbiología, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. postal 510-3, Cuernavaca, 62250, Morelos, Mexico.
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Xu L, Pan ZZ, Zhang J, Niu LY, Li J, Chen Z, Liu B, Zhu YJ, Chen QX. Exposure of helices α4 and α5 is required for insecticidal activity of Cry2Ab by promoting assembly of a prepore oligomeric structure. Cell Microbiol 2018; 20:e12827. [PMID: 29380507 DOI: 10.1111/cmi.12827] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 01/15/2018] [Accepted: 01/17/2018] [Indexed: 12/15/2022]
Abstract
Cry2Ab, a pore-forming toxin derived from Bacillus thuringiensis, is widely used as a bio-insecticide to control lepidopteran pests around the world. A previous study revealed that proteolytic activation of Cry2Ab by Plutella xylostella midgut juice was essential for its insecticidal activity against P. xylostella, although the exact molecular mechanism remained unknown. Here, we demonstrated for the first time that proteolysis of Cry2Ab uncovered an active region (the helices α4 and α5 in Domain I), which was required for the mode of action of Cry2Ab. Either the masking or the removal of helices α4 and α5 mediated the pesticidal activity of Cry2Ab. The exposure of helices α4 and α5 did not facilitate the binding of Cry2Ab to P. xylostella midgut receptors but did induce Cry2Ab monomer to aggregate and assemble a 250-kDa prepore oligomer. Site-directed mutagenesis assay was performed to generate Cry2Ab mutants site directed on the helices α4 and α5, and bioassays suggested that some Cry2Ab variants that could not form oligomers had significantly lowered their toxicities against P. xylostella. Taken together, our data highlight the importance of helices α4 and α5 in the mode of action of Cry2Ab and could lead to more detailed studies on the insecticidal activity of Cry2Ab.
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Affiliation(s)
- Lian Xu
- State Key Laboratory of Cellular Stress Biology, Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Zhi-Zhen Pan
- Agricultural Bio-Resources Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian, People's Republic of China
| | - Jing Zhang
- State Key Laboratory of Cellular Stress Biology, Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Li-Yang Niu
- State Key Laboratory of Cellular Stress Biology, Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Jie Li
- State Key Laboratory of Cellular Stress Biology, Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Zheng Chen
- Agricultural Bio-Resources Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian, People's Republic of China
| | - Bo Liu
- Agricultural Bio-Resources Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian, People's Republic of China
| | - Yu-Jing Zhu
- Agricultural Bio-Resources Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian, People's Republic of China
| | - Qing-Xi Chen
- State Key Laboratory of Cellular Stress Biology, Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen, Fujian, People's Republic of China
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278
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Chandrasena DI, Signorini AM, Abratti G, Storer NP, Olaciregui ML, Alves AP, Pilcher CD. Characterization of field-evolved resistance to Bacillus thuringiensis-derived Cry1F δ-endotoxin in Spodoptera frugiperda populations from Argentina. PEST MANAGEMENT SCIENCE 2018; 74:746-754. [PMID: 29072821 DOI: 10.1002/ps.4776] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 10/19/2017] [Accepted: 10/20/2017] [Indexed: 05/18/2023]
Abstract
BACKGROUND Transgenic maize (Zea mays L.) event TC1507 (Herculex® I insect protection), expressing Cry1F δ-endotoxin derived from Bacillus thuringiensis var. aizawai, was commercialized in 2003 in the Americas. Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) susceptibility to Cry1F was monitored annually across several regions in Argentina using diagnostic concentration bioassays. Reduced performance of TC1507 maize against S. frugiperda was reported in 2013. A resistant population was established in the laboratory and the dominance of Cry1F resistance was characterized. RESULTS During 2012-2015, high-survivorship of several populations was observed in the resistance monitoring program. Reciprocal crosses of a Cry1F-resistant population with a Cry1F-susceptible population were evaluated to calculate effective dominance (DML ) based on mortality levels observed at 100 µg/ml Cry1F. Two additional dominance levels (DLC and DEC ) were calculated using lethal (LC50 ) or effective concentration (EC50 ) derived from concentration-response bioassays. Estimates indicated that Cry1F resistance in S. frugiperda in Argentina was either highly recessive (DML = 0.005) or incompletely recessive (DLC < 0.26 and DEC < 0.19). CONCLUSION This study is the first documented confirmation and characterization of S. frugiperda Cry1F field-evolved resistance in Argentina. The resistance to Cry1F in S. frugiperda populations collected in Argentina, is autosomal and incompletely recessive similar to the resistance reported in Brazil. © 2017 The Authors. Pest Management Science published by John Wiley © Sons Ltd on behalf of Society of Chemical Industry.
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279
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Wang L, Ma Y, Wan P, Liu K, Xiao Y, Wang J, Cong S, Xu D, Wu K, Fabrick JA, Li X, Tabashnik BE. Resistance to Bacillus thuringiensis linked with a cadherin transmembrane mutation affecting cellular trafficking in pink bollworm from China. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 94:28-35. [PMID: 29408651 DOI: 10.1016/j.ibmb.2018.01.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 01/07/2018] [Accepted: 01/22/2018] [Indexed: 05/29/2023]
Abstract
Evolution of pest resistance reduces the efficacy of insecticidal proteins from the gram-positive bacterium Bacillus thuringiensis (Bt) used widely in sprays and transgenic crops. In some previously studied strains of three major lepidopteran pests, resistance to Bt toxin Cry1Ac is associated with mutations disrupting the extracellular or cytoplasmic domains of cadherin proteins that bind Cry1Ac in the midgut of susceptible larvae. Here we report the first case of a cadherin transmembrane mutation associated with insect resistance to Bt. We discovered this mutation in a strain of the devastating global cotton pest, the pink bollworm (Pectinophora gossypiella), derived from a field population in the Yangtze River Valley of China. The mutant allele analyzed here has a 207 base pair deletion and encodes a cadherin protein lacking its transmembrane domain. Relative to a susceptible strain, a strain homozygous for this allele had 220-fold resistance to Cry1Ac and 2.1-fold cross-resistance to Cry2Ab. On transgenic cotton plants producing Cry1Ac, no susceptible larvae survived, but the resistant strain completed its life cycle. Inheritance of resistance to Cry1Ac was autosomal, recessive and tightly linked with the cadherin gene. Transportation of cadherin protein to the cell membrane and susceptibility to Cry1Ac occurred in transfected insect cells expressing the wild type cadherin allele, but not in transfected insect cells expressing the mutant cadherin allele. The results imply that the mutant allele analyzed here confers resistance to Cry1Ac by disrupting cellular trafficking of cadherin.
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Affiliation(s)
- Ling Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; Key Laboratory of Integrated Pest Management on Crops in Central China, Ministry of Agriculture, Hubei Key Laboratory of Crop Disease, Insect Pests and Weeds Control, Institute of Plant Protection and Soil Fertility, Hubei Academy of Agricultural Sciences, Wuhan 430064, China
| | - Yuemin Ma
- School of Life Science, Central China Normal University, Wuhan, 430079, China
| | - Peng Wan
- Key Laboratory of Integrated Pest Management on Crops in Central China, Ministry of Agriculture, Hubei Key Laboratory of Crop Disease, Insect Pests and Weeds Control, Institute of Plant Protection and Soil Fertility, Hubei Academy of Agricultural Sciences, Wuhan 430064, China
| | - Kaiyu Liu
- School of Life Science, Central China Normal University, Wuhan, 430079, China
| | - Yutao Xiao
- Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
| | - Jintao Wang
- Key Laboratory of Integrated Pest Management on Crops in Central China, Ministry of Agriculture, Hubei Key Laboratory of Crop Disease, Insect Pests and Weeds Control, Institute of Plant Protection and Soil Fertility, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, China
| | - Shengbo Cong
- Key Laboratory of Integrated Pest Management on Crops in Central China, Ministry of Agriculture, Hubei Key Laboratory of Crop Disease, Insect Pests and Weeds Control, Institute of Plant Protection and Soil Fertility, Hubei Academy of Agricultural Sciences, Wuhan 430064, China
| | - Dong Xu
- Key Laboratory of Integrated Pest Management on Crops in Central China, Ministry of Agriculture, Hubei Key Laboratory of Crop Disease, Insect Pests and Weeds Control, Institute of Plant Protection and Soil Fertility, Hubei Academy of Agricultural Sciences, Wuhan 430064, China
| | - Kongming Wu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Jeffrey A Fabrick
- USDA, ARS, U.S. Arid Land Agricultural Research Center, Maricopa, AZ 85138, USA
| | - Xianchun Li
- Department of Entomology, University of Arizona, Tucson, AZ 85721, USA
| | - Bruce E Tabashnik
- Department of Entomology, University of Arizona, Tucson, AZ 85721, USA
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280
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Cross-Resistance: A Consequence of Bi-partite Host-Parasite Coevolution. INSECTS 2018; 9:insects9010028. [PMID: 29495405 PMCID: PMC5872293 DOI: 10.3390/insects9010028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 02/02/2018] [Accepted: 02/19/2018] [Indexed: 12/26/2022]
Abstract
Host-parasite coevolution can influence interactions of the host and parasite with the wider ecological community. One way that this may manifest is in cross-resistance towards other parasites, which has been observed to occur in some host-parasite evolution experiments. In this paper, we test for cross-resistance towards Bacillus thuringiensis and Pseudomonasentomophila in the red flour beetle Triboliumcastaneum, which was previously allowed to coevolve with the generalist entomopathogenic fungus Beauveriabassiana. We combine survival and gene expression assays upon infection to test for cross-resistance and underlying mechanisms. We show that larvae of T.castaneum that evolved with B.bassiana under coevolutionary conditions were positively cross-resistant to the bacterium B. thuringiensis, but not P.entomophila. Positive cross-resistance was mirrored at the gene expression level with markers that were representative of the oral route of infection being upregulated upon B.bassiana exposure. We find that positive cross-resistance towards B. thuringiensis evolved in T.castaneum as a consequence of its coevolutionary interactions with B.bassiana. This cross-resistance appears to be a consequence of resistance to oral toxicity. The fact that coevolution with B.bassiana results in resistance to B. thuringiensis, but not P.entomophila implies that B. thuringiensis and B.bassiana may share mechanisms of infection or toxicity not shared by P.entomophila. This supports previous suggestions that B.bassiana may possess Cry-like toxins, similar to those found in B. thuringiensis, which allow it to infect orally.
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281
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Shao E, Lin L, Liu S, Zhang J, Chen X, Sha L, Huang Z, Huang B, Guan X. Analysis of Homologs of Cry-toxin Receptor-Related Proteins in the Midgut of a Non-Bt Target, Nilaparvata lugens (Stål) (Hemiptera: Delphacidae). JOURNAL OF INSECT SCIENCE (ONLINE) 2018; 18:4839024. [PMID: 29415259 PMCID: PMC5804751 DOI: 10.1093/jisesa/iex102] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Indexed: 05/13/2023]
Abstract
The brown planthopper (BPH) Nilaparvata lugens is one of the most destructive insect pests in the rice fields of Asia. Like other hemipteran insects, BPH is not susceptible to Cry toxins of Bacillus thuringiensis (Bt) or transgenic rice carrying Bt cry genes. Lack of Cry receptors in the midgut is one of the main reasons that BPH is not susceptible to the Cry toxins. The main Cry-binding proteins (CBPs) of the susceptible insects are cadherin, aminopeptidase N (APN), and alkaline phosphatase (ALP). In this study, we analyzed and validated de novo assembled transcripts from transcriptome sequencing data of BPH to identify and characterize homologs of cadherin, APN, and ALP. We then compared the cadherin-, APN-, and ALP-like proteins of BPH to previously reported CBPs to identify their homologs in BPH. The sequence analysis revealed that at least one cadherin, one APN, and two ALPs of BPH contained homologous functional domains identified from the Cry-binding cadherin, APN, and ALP, respectively. Quantitative real-time polymerase chain reaction used to verify the expression level of each putative Cry receptor homolog in the BPH midgut indicated that the CBPs homologous APN and ALP were expressed at high or medium-high levels while the cadherin was expressed at a low level. These results suggest that homologs of CBPs exist in the midgut of BPH. However, differences in key motifs of CBPs, which are functional in interacting with Cry toxins, may be responsible for insusceptibility of BPH to Cry toxins.
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Affiliation(s)
- Ensi Shao
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, School of Life Science, Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Key Lab of Biopesticides and Chemical Biology, MOE, Fujian Agriculture and Forestry University, Fuzhou, Fujian, PR China
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, PR China
- China National Engineering Research Center of JUNCAO Technology, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, PR China
| | - Li Lin
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, School of Life Science, Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Key Lab of Biopesticides and Chemical Biology, MOE, Fujian Agriculture and Forestry University, Fuzhou, Fujian, PR China
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, PR China
| | - Sijun Liu
- Department of Entomology, Iowa State University, Ames, IA, 50011
| | - Jiao Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, School of Life Science, Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Key Lab of Biopesticides and Chemical Biology, MOE, Fujian Agriculture and Forestry University, Fuzhou, Fujian, PR China
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, PR China
| | - Xuelin Chen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, School of Life Science, Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Key Lab of Biopesticides and Chemical Biology, MOE, Fujian Agriculture and Forestry University, Fuzhou, Fujian, PR China
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, PR China
| | - Li Sha
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, School of Life Science, Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Key Lab of Biopesticides and Chemical Biology, MOE, Fujian Agriculture and Forestry University, Fuzhou, Fujian, PR China
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, PR China
| | - Zhipeng Huang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, School of Life Science, Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Key Lab of Biopesticides and Chemical Biology, MOE, Fujian Agriculture and Forestry University, Fuzhou, Fujian, PR China
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, PR China
| | - Biwang Huang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, School of Life Science, Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Key Lab of Biopesticides and Chemical Biology, MOE, Fujian Agriculture and Forestry University, Fuzhou, Fujian, PR China
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, PR China
| | - Xiong Guan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, School of Life Science, Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Key Lab of Biopesticides and Chemical Biology, MOE, Fujian Agriculture and Forestry University, Fuzhou, Fujian, PR China
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, PR China
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282
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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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Soberón M, Portugal L, Garcia-Gómez BI, Sánchez J, Onofre J, Gómez I, Pacheco S, Bravo A. Cell lines as models for the study of Cry toxins from Bacillus thuringiensis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 93:66-78. [PMID: 29269111 DOI: 10.1016/j.ibmb.2017.12.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/15/2017] [Accepted: 12/16/2017] [Indexed: 06/07/2023]
Abstract
Cell lines have been use extensively for the study of the mode of action of different pore forming toxins produced by different bacterial species. Bacillus thuringiensis Cry toxins are not the exception and their mechanism of action has been analyzed in different cell lines. Here we review the data obtained with different cell lines, including those that are naturally susceptible to the three domain Cry toxins (3d-Cry) and other non-susceptible cell lines that have been transformed with 3d-Cry toxin binding molecules cloned from the susceptible insects. The effects on Cry toxin action after expressing different insect gut proteins, such as glycosyl-phosphatidyl-inositol (GPI) anchored proteins (like alkaline phosphatase (ALP) aminopeptidase (APN)), or trans-membrane proteins (like cadherin (CAD) or ATP-binding cassette subfamily C member 2 (ABCC2) transporter) in cell lines showed that, with few exceptions, expression of GPI-anchored proteins do not correlated with increased susceptibility to the toxin, while the expression of CAD or ABCC2 proteins correlated with induced susceptibility to Cry toxins in the transformed cells lines. Also, that the co-expression of CAD and ABCC2 transporter induced a synergistic effect in the toxicity of 3d-Cry toxins. Overall the data show that in susceptible cell lines, the 3d-Cry toxins induce pore formation that correlates with toxicity. However, the intracellular responses remain controversial since it was shown that the same 3d-Cry toxin in different cell lines activated different responses such as adenylate cyclase-PKA death response or apoptosis. Parasporins are Cry toxins that are toxic to cancer cell lines that have structural similarities with the insecticidal Cry toxins. They belong to the 3d-Cry toxin or to MTX-like Cry toxin families but also show important differences with the insecticidal Cry proteins. Some parasporins are pore-forming toxins, and some activate apoptosis. In this review we summarized the results of the different studies about the Cry toxins mode of action using cultured cell lines and discuss their relation with the studies performed in insect larvae.
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Affiliation(s)
- Mario Soberón
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico.
| | - Leivi Portugal
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico.
| | - Blanca-Ines Garcia-Gómez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico.
| | - Jorge Sánchez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Janette Onofre
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Isabel Gómez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico.
| | - Sabino Pacheco
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico.
| | - Alejandra Bravo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico.
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284
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Qiu L, Wang P, Wu T, Li B, Wang X, Lei C, Lin Y, Zhao J, Ma W. Downregulation of Chilo suppressalis alkaline phosphatase genes associated with resistance to three transgenic Bacillus thuringiensis rice lines. INSECT MOLECULAR BIOLOGY 2018; 27:83-89. [PMID: 28940938 DOI: 10.1111/imb.12349] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Insecticidal crystal (Cry) proteins produced by the bacterium Bacillus thuringiensis are highly toxic to lepidopteran pests. Strains of transgenic rice expressing cry genes have been developed that are resistant to rice pests. Understanding the mode of action of Cry toxins in rice pests will improve our ability to use them effectively as insecticides. In this study, we tested the hypothesis that alkaline phosphatases (ALPs) are involved in Cry1A, Cry2Aa and Cry1Ca toxicity in Chilo suppressalis, an important insect pest of rice crops in China. We first cloned three novel C. suppressalis alps (Csalps) from the larval midgut of C. suppressalis. RNA interference knockdown of six different Csalp genes (Csalp1, Csalp2, Csalp3, Csalp4, Csalp5 and Csalp6) showed that knockdown of three of these, Csalp1, Csalp2 and Csalp4, reduced larval mortality to the transgenic rice strain TT51, which expresses a fusion protein of Cry1Ab and Cry1Ac, whereas suppression of Csalp1, Csalp2, Csalp3, Csalp4 and Csalp6 transcripts decreased the susceptibility of larvae to the transgenic rice strain T2A-1, which expresses cry2Aa. Moreover, downregulation of Csalp1, Csalp2, Csalp3, Csalp4 and Csalp5 transcripts conferred significant tolerance to the transgenic rice strain T1C-19, which expresses cry1Ca. These results suggest that these ALPs play a key role in the toxicity of Cry1A, Cry2A and Cry1C to C. suppressalis.
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Affiliation(s)
- L Qiu
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Wuhan, China
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - P Wang
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - T Wu
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - B Li
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - X Wang
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - C Lei
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Y Lin
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Wuhan, China
| | - J Zhao
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Wuhan, China
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - W Ma
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Wuhan, China
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
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285
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BenFarhat-Touzri D, Driss F, Jemli S, Tounsi S. Molecular characterization of Cry1D-133 toxin from Bacillus thuringiensis strain HD133 and its toxicity against Spodoptera littoralis. Int J Biol Macromol 2018; 112:1-6. [PMID: 29366893 DOI: 10.1016/j.ijbiomac.2018.01.081] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 01/12/2018] [Accepted: 01/13/2018] [Indexed: 10/18/2022]
Abstract
Bacillus thuringiensis subsp. aizawai strain HD133, known by its effectiveness against Spodoptera species, produces bipyramidal crystals encompassing the insecticidal proteins Cry1Ab, Cry1Ca and Cry1D-133 in the proportions 60:37:3, respectively. In this study, we dealt with the relevance of the low rate of Cry1D-133. The cry1D-133 gene from HD133 was cloned and sequenced. Both nucleotide and amino acid sequence similarity analyses with the cry1D genes available in the GenBank database revealed that cry1D-133 is a new variant of cry1Da-type genes with 99% identity with cry1Da1. Molecular modeling of the Cry1D-133 toxin showed that its higher toxicity is correlated to a higher number of toxin-receptor interactions. Optimal culture conditions of 4 h post-induction time, 160 rpm agitation and 37 °C post-induction temperature were determined and adopted to overproduce Cry1D-133 toxin at adequate amounts to carryout bioassays. A gradual increase of the proportion of Cry1D-133 to the HD133 insecticidal proteins forming the crystal (Cry1D-133, Cry1Ca and Cry1Ab) showed an improvement of the toxicity against Spodoptera littoralis larvae. Therefore, the potential of Cry1D-133 to enhance HD133 toxicity could promote its combination with other B. thuringiensis insecticidal proteins toxins in order to increase target range or to delay the emergence of resistance.
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Affiliation(s)
- Dalel BenFarhat-Touzri
- Laboratory of Biopesticides, Centre of Biotechnology of Sfax, University of Sfax, P.O. Box, "1177", 3018, Sfax, Tunisia
| | - Fatma Driss
- Laboratory of Biopesticides, Centre of Biotechnology of Sfax, University of Sfax, P.O. Box, "1177", 3018, Sfax, Tunisia.
| | - Sonia Jemli
- Laboratory of Microbial Biotechnology and Enzyme Engineering, Centre of Biotechnology of Sfax, University of Sfax, P.O. Box, "1177", 3018, Sfax, Tunisia
| | - Slim Tounsi
- Laboratory of Biopesticides, Centre of Biotechnology of Sfax, University of Sfax, P.O. Box, "1177", 3018, Sfax, Tunisia
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286
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Yang Y, Xu H, Lu Y, Wang C, Lu Z. Midgut transcriptomal response of the rice leaffolder, Cnaphalocrocis medinalis (Guenée) to Cry1C toxin. PLoS One 2018; 13:e0191686. [PMID: 29360856 PMCID: PMC5779695 DOI: 10.1371/journal.pone.0191686] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 01/09/2018] [Indexed: 12/24/2022] Open
Abstract
Cnaphalocrocis medinalis (Guenée) is one of the important insect pests in rice field. Bt agents were recommended in the C. medinalis control and Bt rice is bred as a tactic to control this insect. However, the tolerance or resistance of insect to Bt protein is a main threat to the application of Bt protein. In order to investigate the response of C. medinalis transcriptome in defending a Cry1C toxin, high-through RNA-sequencing was carried in the C. medinalis larvae treated with and without Cry1C toxin. A total of 35,586 high-quality unigenes was annotated in the transcriptome of C. medinalis midgut. The comparative analysis identified 6,966 differently expressed unigenes (DEGs) between the two treatments. GO analysis showed that these genes involved in proteolysis and extracellular region. Among these DEGs, carboxylesterase, glutathione S-transferase and P450 were differently expressed in the treated C. medinalis midgut. Furthermore, trypsin, chymotrypsin, and carboxypeptidase were identified in DEGs, and most of them up-regulated. In addition, thirteen ABC transporters were downregulated and three upregulated in Cry1C-treated C. medinalis midgut. Based on the pathway analysis, antigen processing and presentation pathway, and chronic myeloid leukemia pathway were significant in C. medinalis treated with Cry1C toxin. These results indicated that serine protease, detoxification enzymes and ABC transporter, antigen processing and presentation pathway, and chronic myeloid leukemia pathway may involved in the response of C. medinalis to Cry1C toxin. This study provides a transcriptomal foundation for the identification and functional characterization of genes involved in the toxicity of Bt Cry protein against C. medinalis, and provides potential clues to the studies on the tolerance or resistance of an agriculturally important insect pest C. medinalis to Cry1C toxin.
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Affiliation(s)
- Yajun Yang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Hongxing Xu
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Yanhui Lu
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Caiyun Wang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Zhongxian Lu
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
- * E-mail:
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287
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Li S, Wang Z, Zhou Y, Li C, Wang G, Wang H, Zhang J, Liang G, Lang Z. Expression of cry2Ah1 and two domain II mutants in transgenic tobacco confers high resistance to susceptible and Cry1Ac-resistant cotton bollworm. Sci Rep 2018; 8:508. [PMID: 29323243 PMCID: PMC5765002 DOI: 10.1038/s41598-017-19064-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 12/20/2017] [Indexed: 12/11/2022] Open
Abstract
To improve the novel Bacillus thuringiensis insecticidal gene cry2Ah1 toxicity, two mutants cry2Ah1-vp (V354VP) and cry2Ah1-sp (V354SP) were performed. SWISS-MODEL analysis showed two mutants had a longer loop located between β-4 and β-5 of domain II, resulting in higher binding affinity with brush border membrane vesicles (BBMV) of Helicoverpa armigera comparing with Cry2Ah1. The cry2Ah1, cry2Ah1-vp, and cry2Ah1-sp were optimized codon usage according to plant codon bias, and named mcry2Ah1, mcry2Ah1-vp, and mcry2Ah1-sp. They were transformed into tobacco via Agrobacterium-mediated transformation and a total of 4, 8, and 24 transgenic tobacco plants were obtained, respectively. The molecular detection showed the exogenous gene was integrated into tobacco genome, and successfully expressed at the transcript and translation levels. Cry2Ah1 protein in transgenic tobacco plants varied from 4.41 to 40.28 μg g-1 fresh weight. Insect bioassays indicated that all transgenic tobacco plants were highly toxic to both susceptible and Cry1Ac-resistant cotton bollworm larvae, and the insect resistance efficiency to Cry1Ac-resistant cotton bollworm was highest in mcry2Ah1-sp transgenic tobacco plants. The results demonstrated that cry2Ah1 was a useful Bt insecticidal gene to susceptible and Cry1Ac-resistant cotton bollworm and had potential application for insect biocontrol and as a candidate for pyramid strategy in Bt crops.
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Affiliation(s)
- Shengyan Li
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Zeyu Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Yiyao Zhou
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Changhui Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Guiping Wang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Hai Wang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Jie Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Gemei Liang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Zhihong Lang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
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288
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Soberón M, Monnerat R, Bravo A. Mode of Action of Cry Toxins from Bacillus thuringiensis and Resistance Mechanisms. TOXINOLOGY 2018. [DOI: 10.1007/978-94-007-6449-1_28] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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289
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Pietri JE, Liang D. Virulence of entomopathogenic bacteria in the bed bug, Cimex lectularius. J Invertebr Pathol 2018; 151:1-6. [DOI: 10.1016/j.jip.2017.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 10/11/2017] [Accepted: 10/20/2017] [Indexed: 01/26/2023]
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290
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PxAPN5 serves as a functional receptor of Cry2Ab in Plutella xylostella (L.) and its binding domain analysis. Int J Biol Macromol 2017; 105:516-521. [DOI: 10.1016/j.ijbiomac.2017.07.070] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 07/10/2017] [Accepted: 07/11/2017] [Indexed: 01/12/2023]
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291
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Onofre J, Gaytán MO, Peña-Cardeña A, García-Gomez BI, Pacheco S, Gómez I, Bravo A, Soberón M. Identification of Aminopeptidase-N2 as a Cry2Ab binding protein in Manduca sexta. Peptides 2017; 98:93-98. [PMID: 28108197 DOI: 10.1016/j.peptides.2017.01.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 01/06/2017] [Accepted: 01/09/2017] [Indexed: 11/15/2022]
Abstract
Bacillus thuringiensis Cry2Ab toxin has been used in combination with Cry1Ac for resistance management on the Bt-cotton that is widely planted worldwide. However, little is known regarding Cry2Ab mode of action. Particularly, there is a gap of knowledge on the identification of insect midgut proteins that bind Cry2Ab and mediate toxicity. In the case of Cry1Ab toxin, a transmembrane cadherin protein and glycosyl-phosphatidylinositol (GPI) anchored proteins like aminopeptidase-N1 (APN1) or alkaline-phosphatase (ALP) from Manduca sexta, have been shown to be important for oligomer formation and insertion into the membrane. Binding competition experiments showed that Cry2Ab toxin does not share binding sites with Cry1Ab toxin in M. sexta brush border membrane vesicles (BBMV). Also, that Cry2Ab shows reduced binding to the Cry1Ab binding molecules cadherin, APN1 or ALP. Finally, ligand blot experiments and protein sequence by LC-MS/MS identified APN2 isoform as a Cry2Ab binding protein. Cloning and expression of APN2 confirmed that APN2 is a Cry2Ab binding protein.
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Affiliation(s)
- Janette Onofre
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo, Postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Meztlli O Gaytán
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo, Postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Arlen Peña-Cardeña
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo, Postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Blanca I García-Gomez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo, Postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Sabino Pacheco
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo, Postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Isabel Gómez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo, Postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Alejandra Bravo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo, Postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Mario Soberón
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo, Postal 510-3, Cuernavaca 62250, Morelos, Mexico.
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292
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Chen J, Aimanova K, Gill SS. Functional characterization of Aedes aegypti alkaline phosphatase ALP1 involved in the toxicity of Cry toxins from Bacillus thuringiensis subsp. israelensis and jegathesan. Peptides 2017; 98:78-85. [PMID: 28587836 PMCID: PMC5705450 DOI: 10.1016/j.peptides.2017.05.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 05/24/2017] [Accepted: 05/30/2017] [Indexed: 10/19/2022]
Abstract
Presently three major groups of proteins from Aedes aegypti, cadherin, alkaline phosphatases (ALP) and aminopeptidases N (APN), have been identified as Cry11Aa toxin receptors. To further characterize their role on toxicity, transgenic mosquitoes with silenced Aedes cadherin expression were previously generated and the role of cadherin in mediating the toxicity of four different mosquitocidal toxins (Cry11Aa, Cry11Ba, Cry4Aa and Cry4Ba) was demonstrated. Here, we investigated the role of another reported Cry11Aa receptor, ALP1. As with Aedes cadherin, this protein is localized in the apical cell membrane of distal and proximal gastric caecae and the posterior midgut. We also successfully generated transgenic mosquitoes that knockdowned ALP1 transcript levels using an inducible Aedes heat shock promoter, Hsp70A driving dsALP1RNA. Four different mosquitocidal toxins were used for larval bioassays against this transgenic mosquito. Bioassay results show thatCry11Aa toxicity to these transgenic larvae following a heat shock decreased (4.4 fold) and Cry11Ba toxicity is slightly attenuated. But Cry4Aa and Cry4Ba toxicity to ALP1 silenced larvae is unchanged. Without heat shock, toxicity of all four toxins does not change, suggesting this heat shock promoter is heat-inducible. Notably, transgenic mosquitoes with ALP1 knockdown are about 3.7 times less resistant to Cry11Aa toxin than those with Aedes cadherin knockdown. These results demonstrate that the ALP1 is an important secondary receptor for Cry11Aa and Cry11Ba, but it might not be involved in Cry4Aa and Cry4Ba toxicity.
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Affiliation(s)
- Jianwu Chen
- Departmentof Cell Biology and Neurosciences, University of California, Riverside, CA 92521, United States.
| | - Karly Aimanova
- Departmentof Cell Biology and Neurosciences, University of California, Riverside, CA 92521, United States
| | - Sarjeet S Gill
- Departmentof Cell Biology and Neurosciences, University of California, Riverside, CA 92521, United States
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293
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Structural Insights into the Cytotoxic Mechanism of Vibrio parahaemolyticus PirA vp and PirB vp Toxins. Mar Drugs 2017; 15:md15120373. [PMID: 29194352 PMCID: PMC5742833 DOI: 10.3390/md15120373] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 11/14/2017] [Accepted: 11/17/2017] [Indexed: 02/01/2023] Open
Abstract
In aquaculture, shrimp farming is a popular field. The benefits of shrimp farming include a relatively short grow-out time, high sale price, and good cost recovery. However, outbreaks of serious diseases inflict serious losses, and acute hepatopancreatic necrosis disease (AHPND) is an emerging challenge to this industry. In South American white shrimp (Penaeus vannamei) and grass shrimp (Penaeus monodon), this disease has a 70–100% mortality. The pathogenic agent of AHPND is a specific strain of Vibrio parahaemolyticus which contains PirAvp and PirBvp toxins encoded in the pVA1 plasmid. PirAvp and PirBvp have been shown to cause the typical histological symptoms of AHPND in infected shrimps, and in this review, we will focus on our structural understanding of these toxins. By analyzing their structures, a possible cytotoxic mechanism, as well as strategies for anti-AHPND drug design, is proposed.
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294
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Pool deconvolution approach for high-throughput gene mining from Bacillus thuringiensis. Appl Microbiol Biotechnol 2017; 102:1467-1482. [DOI: 10.1007/s00253-017-8633-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 10/24/2017] [Accepted: 11/05/2017] [Indexed: 11/27/2022]
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295
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Changes in gene expression and apoptotic response in Spodoptera exigua larvae exposed to sublethal concentrations of Vip3 insecticidal proteins. Sci Rep 2017; 7:16245. [PMID: 29176692 PMCID: PMC5701239 DOI: 10.1038/s41598-017-16406-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 11/12/2017] [Indexed: 01/24/2023] Open
Abstract
The insecticidal Vip3 proteins from Bacillus thuringiensis (Bt), along with the classical Bt Cry proteins, are currently used in Bt-crops to control insect pests, since they do not share the same mode of action. Here we characterized the response of Spodoptera exigua larvae after Vip3 challenge. The expression profile of 47 genes was analyzed in larvae challenged with three concentrations of Vip3Ca. Results showed that the up-regulated genes were mainly involved in immune response, whereas the down-regulated genes were mainly involved in the digestion process. Other mechanisms of cellular response to the damage such as apoptosis were analyzed. For this analysis, sections from the midguts were examined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. The nuclei of the midgut epithelial cells were stained at the highest concentration of the Vip3Ca protein and at lower concentrations of Vip3Aa in agreement with the different potency of the two proteins. In addition, apoptosis was also examined by the analysis of the expression of five caspase genes. The present study shows that exposure of S. exigua larvae to sublethal concentrations of Vip3 proteins activates different insect response pathways which trigger the regulation of some genes, APN shedding, and apoptotic cell death.
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296
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Bierne H, Nielsen-LeRoux C. Is there a transgenerational inheritance of host resistance against pathogens? Lessons from the Galleria mellonella-Bacillus thuringiensis interaction model. Virulence 2017; 8:1471-1474. [PMID: 28758839 PMCID: PMC5810474 DOI: 10.1080/21505594.2017.1356538] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 07/06/2017] [Indexed: 12/13/2022] Open
Affiliation(s)
- Hélène Bierne
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
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297
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Using phage display technology to obtain Crybodies active against non-target insects. Sci Rep 2017; 7:14922. [PMID: 29097681 PMCID: PMC5668233 DOI: 10.1038/s41598-017-09384-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 07/26/2017] [Indexed: 11/09/2022] Open
Abstract
The insecticidal Cry toxins produced by Bacillus thuringiensis (Bt) are increasingly important in the biological control of insect pests and vectors of human disease. Markets for Bt products and transgenic plants expressing their toxins are driven by their specificity, safety and the move away from chemical control agents. However, the high specificity of Cry toxins can also prove to be a limitation when there is no known Cry toxin active against a particular target. Novel activities can be discovered by screening natural Bt isolates or through modifications of the Cry proteins. Here we demonstrate the use of λ-phage displaying Cry1Aa13 toxin variants modified in domain II loop 2 (Crybodies) to select retargeted toxins. Through biopanning using gut tissue from larvae of the non-target insect Aedes aegypti, we isolated a number of phage for further testing. Two of the overexpressed Cry toxin variants showed significant activity against A. aegypti larvae while another induced mortality at the pupal stage. We present the first report of the use of phage display to identify novel activities toward insects from distant taxonomic Orders and establish this technology based on the use of Crybodies as a powerful tool for developing tailor-made insecticides against new target insects.
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Labreuche Y, Chenivesse S, Jeudy A, Le Panse S, Boulo V, Ansquer D, Pagès S, Givaudan A, Czjzek M, Le Roux F. Nigritoxin is a bacterial toxin for crustaceans and insects. Nat Commun 2017; 8:1248. [PMID: 29093459 PMCID: PMC5665878 DOI: 10.1038/s41467-017-01445-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 09/14/2017] [Indexed: 11/29/2022] Open
Abstract
The Tetraconata (Pancrustacea) concept proposes that insects are more closely related to aquatic crustaceans than to terrestrial centipedes or millipedes. The question therefore arises whether insects have kept crustacean-specific genetic traits that could be targeted by specific toxins. Here we show that a toxin (nigritoxin), originally identified in a bacterial pathogen of shrimp, is lethal for organisms within the Tetraconata and non-toxic to other animals. X-ray crystallography reveals that nigritoxin possesses a new protein fold of the α/β type. The nigritoxin N-terminal domain is essential for cellular translocation and likely encodes specificity for Tetraconata. Once internalized by eukaryotic cells, nigritoxin induces apoptotic cell death through structural features that are localized in the C-terminal domain of the protein. We propose that nigritoxin will be an effective means to identify a Tetraconata evolutionarily conserved pathway and speculate that nigritoxin holds promise as an insecticidal protein. The Tetraconata concept suggests that insects and crustaceans may share evolutionarily conserved pathways. Here, the authors describe the animal tropism and structure-function relationship of nigritoxin, showing that this protein is lethal for insects and crustaceans but harmless to other animals.
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Affiliation(s)
- Yannick Labreuche
- Ifremer, Unité Physiologie Fonctionnelle des Organismes Marins, ZI de la Pointe du Diable, CS 10070, F-29280, Plouzané, France.,Sorbonne Universités, UPMC Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff cedex, France
| | - Sabine Chenivesse
- Sorbonne Universités, UPMC Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff cedex, France
| | - Alexandra Jeudy
- Sorbonne Universités, UPMC Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff cedex, France
| | - Sophie Le Panse
- CNRS, FR 2424, Plateforme Merimage, Station Biologique de Roscoff, Place Georges Teissier, CS 90074, F-29688, Roscoff cedex, France
| | - Viviane Boulo
- Département Lagons, Ecosystèmes et Aquaculture Durables en Nouvelle-Calédonie, IFREMER, BP 2059, 98846, Nouméa cedex, New Caledonia
| | - Dominique Ansquer
- Département Lagons, Ecosystèmes et Aquaculture Durables en Nouvelle-Calédonie, IFREMER, BP 2059, 98846, Nouméa cedex, New Caledonia
| | - Sylvie Pagès
- UMR 1333 "Diversité, Génomes & Interactions Microorganismes - Insectes" Université Montpellier 2 - Place Eugène Bataillon, 34095, Montpellier cedex 5, France
| | - Alain Givaudan
- UMR 1333 "Diversité, Génomes & Interactions Microorganismes - Insectes" Université Montpellier 2 - Place Eugène Bataillon, 34095, Montpellier cedex 5, France
| | - Mirjam Czjzek
- Sorbonne Universités, UPMC Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff cedex, France
| | - Frédérique Le Roux
- Ifremer, Unité Physiologie Fonctionnelle des Organismes Marins, ZI de la Pointe du Diable, CS 10070, F-29280, Plouzané, France. .,Sorbonne Universités, UPMC Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff cedex, France.
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299
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Wang B, Wang H, Xiong J, Zhou Q, Wu H, Xia L, Li L, Yu Z. A Proteomic Analysis Provides Novel Insights into the Stress Responses of Caenorhabditis elegans towards Nematicidal Cry6A Toxin from Bacillus thuringiensis. Sci Rep 2017; 7:14170. [PMID: 29074967 PMCID: PMC5658354 DOI: 10.1038/s41598-017-14428-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 10/10/2017] [Indexed: 01/16/2023] Open
Abstract
Cry6A represents a novel family of nematicidal crystal proteins from Bacillus thuringiensis. It has distinctive architecture as well as mechanism of action from Cry5B, a highly focused family of nematicidal crystal proteins, and even from other insecticidal crystal proteins containing the conserved three-domain. However, how nematode defends against Cry6A toxin remains obscure. In this study, the global defense pattern of Caenorhabditis elegans against Cry6Aa2 toxin was investigated by proteomic analysis. In response to Cry6Aa2, 12 proteins with significantly altered abundances were observed from worms, participating in innate immune defense, insulin-like receptor (ILR) signaling pathway, energy metabolism, and muscle assembly. The differentially expressed proteins (DEPs) functioning in diverse biological processes suggest that a variety of defense responses participate in the stress responses of C. elegans to Cry6Aa2. The functional verifications of DEPs suggest that ILR signaling pathway, DIM-1, galectin LEC-6 all are the factors of defense responses to Cry6Aa2. Moreover, Cry6Aa2 also involves in accelerating the metabolic energy production which fulfills the energy demand for the immune responses. In brief, our findings illustrate the global pattern of defense responses of nematode against Cry6A for the first time, and provide a novel insight into the mechanism through which worms respond to Cry6A.
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Affiliation(s)
- Bing Wang
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410081, P.R. China
| | - Haiwen Wang
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410081, P.R. China
| | - Jing Xiong
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410081, P.R. China
| | - Qiaoni Zhou
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410081, P.R. China
| | - Huan Wu
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410081, P.R. China
| | - Liqiu Xia
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410081, P.R. China
| | - Lin Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, P.R. China
| | - Ziquan Yu
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410081, P.R. China.
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300
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Surge in insect resistance to transgenic crops and prospects for sustainability. Nat Biotechnol 2017; 35:926-935. [DOI: 10.1038/nbt.3974] [Citation(s) in RCA: 344] [Impact Index Per Article: 49.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 08/25/2017] [Indexed: 12/25/2022]
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