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Tetreau G, Sawaya MR, De Zitter E, Andreeva EA, Banneville AS, Schibrowsky NA, Coquelle N, Brewster AS, Grünbein ML, Kovacs GN, Hunter MS, Kloos M, Sierra RG, Schiro G, Qiao P, Stricker M, Bideshi D, Young ID, Zala N, Engilberge S, Gorel A, Signor L, Teulon JM, Hilpert M, Foucar L, Bielecki J, Bean R, de Wijn R, Sato T, Kirkwood H, Letrun R, Batyuk A, Snigireva I, Fenel D, Schubert R, Canfield EJ, Alba MM, Laporte F, Després L, Bacia M, Roux A, Chapelle C, Riobé F, Maury O, Ling WL, Boutet S, Mancuso A, Gutsche I, Girard E, Barends TRM, Pellequer JL, Park HW, Laganowsky AD, Rodriguez J, Burghammer M, Shoeman RL, Doak RB, Weik M, Sauter NK, Federici B, Cascio D, Schlichting I, Colletier JP. De novo determination of mosquitocidal Cry11Aa and Cry11Ba structures from naturally-occurring nanocrystals. Nat Commun 2022; 13:4376. [PMID: 35902572 PMCID: PMC9334358 DOI: 10.1038/s41467-022-31746-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 06/30/2022] [Indexed: 11/08/2022] Open
Abstract
Cry11Aa and Cry11Ba are the two most potent toxins produced by mosquitocidal Bacillus thuringiensis subsp. israelensis and jegathesan, respectively. The toxins naturally crystallize within the host; however, the crystals are too small for structure determination at synchrotron sources. Therefore, we applied serial femtosecond crystallography at X-ray free electron lasers to in vivo-grown nanocrystals of these toxins. The structure of Cry11Aa was determined de novo using the single-wavelength anomalous dispersion method, which in turn enabled the determination of the Cry11Ba structure by molecular replacement. The two structures reveal a new pattern for in vivo crystallization of Cry toxins, whereby each of their three domains packs with a symmetrically identical domain, and a cleavable crystal packing motif is located within the protoxin rather than at the termini. The diversity of in vivo crystallization patterns suggests explanations for their varied levels of toxicity and rational approaches to improve these toxins for mosquito control.
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Affiliation(s)
- Guillaume Tetreau
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des martyrs, F-38000, Grenoble, France
| | - Michael R Sawaya
- UCLA-DOE Institute for Genomics and Proteomics, Department of Biological Chemistry, University of California, Los Angeles, CA, 90095-1570, USA
| | - Elke De Zitter
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des martyrs, F-38000, Grenoble, France
| | - Elena A Andreeva
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des martyrs, F-38000, Grenoble, France
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Anne-Sophie Banneville
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des martyrs, F-38000, Grenoble, France
| | - Natalie A Schibrowsky
- UCLA-DOE Institute for Genomics and Proteomics, Department of Biological Chemistry, University of California, Los Angeles, CA, 90095-1570, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
| | - Nicolas Coquelle
- Large-Scale Structures Group, Institut Laue-Langevin, F-38000, Grenoble, France
| | - Aaron S Brewster
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Marie Luise Grünbein
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Gabriela Nass Kovacs
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Mark S Hunter
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Marco Kloos
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
- European XFEL GmbH, Holzkoppel 4, 22869, Schenefeld, Germany
| | - Raymond G Sierra
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Giorgio Schiro
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des martyrs, F-38000, Grenoble, France
| | - Pei Qiao
- Department of Chemistry, Texas A&M University, College Station, TX, 77845, USA
| | - Myriam Stricker
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Dennis Bideshi
- Department of Entomology and Institute for Integrative Genome Biology, University of California, Riverside, CA, 92521, USA
- Department of Biological Sciences, California Baptist University, Riverside, CA, 92504, USA
| | - Iris D Young
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Ninon Zala
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des martyrs, F-38000, Grenoble, France
| | - Sylvain Engilberge
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des martyrs, F-38000, Grenoble, France
| | - Alexander Gorel
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Luca Signor
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des martyrs, F-38000, Grenoble, France
| | - Jean-Marie Teulon
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des martyrs, F-38000, Grenoble, France
| | - Mario Hilpert
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Lutz Foucar
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Johan Bielecki
- European XFEL GmbH, Holzkoppel 4, 22869, Schenefeld, Germany
| | - Richard Bean
- European XFEL GmbH, Holzkoppel 4, 22869, Schenefeld, Germany
| | - Raphael de Wijn
- European XFEL GmbH, Holzkoppel 4, 22869, Schenefeld, Germany
| | - Tokushi Sato
- European XFEL GmbH, Holzkoppel 4, 22869, Schenefeld, Germany
| | - Henry Kirkwood
- European XFEL GmbH, Holzkoppel 4, 22869, Schenefeld, Germany
| | - Romain Letrun
- European XFEL GmbH, Holzkoppel 4, 22869, Schenefeld, Germany
| | - Alexander Batyuk
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Irina Snigireva
- European Synchrotron Radiation Facility (ESRF), BP 220, 38043, Grenoble, France
| | - Daphna Fenel
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des martyrs, F-38000, Grenoble, France
| | - Robin Schubert
- European XFEL GmbH, Holzkoppel 4, 22869, Schenefeld, Germany
| | - Ethan J Canfield
- Mass Spectrometry Core Facility, School of Pharmacy, University of Southern California, Los Angeles, CA, 90089, USA
| | - Mario M Alba
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, 90089, USA
| | | | | | - Maria Bacia
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des martyrs, F-38000, Grenoble, France
| | - Amandine Roux
- Univ. Lyon, ENS de Lyon, CNRS UMR 5182, Université Claude Bernard Lyon 1, Laboratoire de Chimie, F-69342, Lyon, France
| | | | - François Riobé
- Univ. Lyon, ENS de Lyon, CNRS UMR 5182, Université Claude Bernard Lyon 1, Laboratoire de Chimie, F-69342, Lyon, France
| | - Olivier Maury
- Univ. Lyon, ENS de Lyon, CNRS UMR 5182, Université Claude Bernard Lyon 1, Laboratoire de Chimie, F-69342, Lyon, France
| | - Wai Li Ling
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des martyrs, F-38000, Grenoble, France
| | - Sébastien Boutet
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Adrian Mancuso
- European XFEL GmbH, Holzkoppel 4, 22869, Schenefeld, Germany
| | - Irina Gutsche
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des martyrs, F-38000, Grenoble, France
| | - Eric Girard
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des martyrs, F-38000, Grenoble, France
| | - Thomas R M Barends
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Jean-Luc Pellequer
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des martyrs, F-38000, Grenoble, France
| | - Hyun-Woo Park
- Department of Entomology and Institute for Integrative Genome Biology, University of California, Riverside, CA, 92521, USA
- Department of Biological Sciences, California Baptist University, Riverside, CA, 92504, USA
| | - Arthur D Laganowsky
- Department of Chemistry, Texas A&M University, College Station, TX, 77845, USA
| | - Jose Rodriguez
- UCLA-DOE Institute for Genomics and Proteomics, Department of Biological Chemistry, University of California, Los Angeles, CA, 90095-1570, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
| | - Manfred Burghammer
- European Synchrotron Radiation Facility (ESRF), BP 220, 38043, Grenoble, France
| | - Robert L Shoeman
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - R Bruce Doak
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Martin Weik
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des martyrs, F-38000, Grenoble, France
| | - Nicholas K Sauter
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Brian Federici
- Department of Entomology and Institute for Integrative Genome Biology, University of California, Riverside, CA, 92521, USA
| | - Duilio Cascio
- UCLA-DOE Institute for Genomics and Proteomics, Department of Biological Chemistry, University of California, Los Angeles, CA, 90095-1570, USA
| | - Ilme Schlichting
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Jacques-Philippe Colletier
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 Avenue des martyrs, F-38000, Grenoble, France.
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Bacterial Toxins Active against Mosquitoes: Mode of Action and Resistance. Toxins (Basel) 2021; 13:toxins13080523. [PMID: 34437394 PMCID: PMC8402332 DOI: 10.3390/toxins13080523] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/18/2021] [Accepted: 06/19/2021] [Indexed: 12/25/2022] Open
Abstract
Larvicides based on the bacteria Bacillus thuringiensis svar. israelensis (Bti) and Lysinibacillus sphaericus are effective and environmentally safe compounds for the control of dipteran insects of medical importance. They produce crystals that display specific and potent insecticidal activity against larvae. Bti crystals are composed of multiple protoxins: three from the three-domain Cry type family, which bind to different cell receptors in the midgut, and one cytolytic (Cyt1Aa) protoxin that can insert itself into the cell membrane and act as surrogate receptor of the Cry toxins. Together, those toxins display a complex mode of action that shows a low risk of resistance selection. L. sphaericus crystals contain one major binary toxin that display an outstanding persistence in field conditions, which is superior to Bti. However, the action of the Bin toxin based on its interaction with a single receptor is vulnerable for resistance selection in insects. In this review we present the most recent data on the mode of action and synergism of these toxins, resistance issues, and examples of their use worldwide. Data reported in recent years improved our understanding of the mechanism of action of these toxins, showed that their combined use can enhance their activity and counteract resistance, and reinforced their relevance for mosquito control programs in the future years.
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Tetreau G, Andreeva EA, Banneville AS, De Zitter E, Colletier JP. Can (We Make) Bacillus thuringiensis Crystallize More Than Its Toxins? Toxins (Basel) 2021; 13:toxins13070441. [PMID: 34206749 PMCID: PMC8309801 DOI: 10.3390/toxins13070441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/22/2021] [Accepted: 06/24/2021] [Indexed: 11/16/2022] Open
Abstract
The development of finely tuned and reliable crystallization processes to obtain crystalline formulations of proteins has received growing interest from different scientific fields, including toxinology and structural biology, as well as from industry, notably for biotechnological and medical applications. As a natural crystal-making bacterium, Bacillus thuringiensis (Bt) has evolved through millions of years to produce hundreds of highly structurally diverse pesticidal proteins as micrometer-sized crystals. The long-term stability of Bt protein crystals in aqueous environments and their specific and controlled dissolution are characteristics that are particularly sought after. In this article, we explore whether the crystallization machinery of Bt can be hijacked as a means to produce (micro)crystalline formulations of proteins for three different applications: (i) to develop new bioinsecticidal formulations based on rationally improved crystalline toxins, (ii) to functionalize crystals with specific characteristics for biotechnological and medical applications, and (iii) to produce microcrystals of custom proteins for structural biology. By developing the needs of these different fields to figure out if and how Bt could meet each specific requirement, we discuss the already published and/or patented attempts and provide guidelines for future investigations in some underexplored yet promising domains.
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Chen Y, Zhou X, Guo K, Chen SN, Su X. Transcriptomic insights into the effects of CytCo, a novel nematotoxic protein, on the pine wood nematode Bursaphelenchus xylophilus. BMC Genomics 2021; 22:394. [PMID: 34044778 PMCID: PMC8157652 DOI: 10.1186/s12864-021-07714-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 05/04/2021] [Indexed: 11/24/2022] Open
Abstract
Background The pine wood nematode Bursaphelenchus xylophilus is a destructive pest of Pinus trees worldwide and lacks effective control measures. Screening for nematotoxic proteins has been undertaken to develop new strategies for nematode control. Results The results of the present study provided initial insights into the responses of B. xylophilus exposed to a nematotoxic cytolytic-like protein (CytCo) based on transcriptome profiling. A large set of differentially expressed genes (DEGs = 1265) was found to be related to nematode development, reproduction, metabolism, motion, and immune system. In response to the toxic protein, B. xylophilus upregulated DEGs encoding cuticle collagens, transporters, and cytochrome P450. In addition, many DEGs related to cell death, lipid metabolism, major sperm proteins, proteinases/peptidases, phosphatases, kinases, virulence factors, and transthyretin-like proteins were downregulated. Gene Ontology enrichment analysis showed that the CytCo treatment substantially affected DEGs involved in muscle contraction, lipid localization, and the mitogen-activated protein kinase cascade. The pathway richness of the Kyoto Encyclopedia of Genes and Genomes showed that the DEGs were concentrated in lysosomes and involved in fatty acid degradation. Weighted co-expression network analysis indicated that the hub genes affected by CytCo were associated with the nematode cuticular collagen. Conclusions These results showed that CytCo toxin interferes with gene expression to exert multiple nematotoxic effects, thereby providing insights into its potential use in pine wood nematode control. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07714-y.
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Affiliation(s)
- Ye Chen
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory for High-Efficient Preparation of Biopesticide, School of Forestry and Biotechnology, Zhejiang A&F University, 311300, Hangzhou, People's Republic of China
| | - Xiang Zhou
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory for High-Efficient Preparation of Biopesticide, School of Forestry and Biotechnology, Zhejiang A&F University, 311300, Hangzhou, People's Republic of China
| | - Kai Guo
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory for High-Efficient Preparation of Biopesticide, School of Forestry and Biotechnology, Zhejiang A&F University, 311300, Hangzhou, People's Republic of China.
| | - Sha-Ni Chen
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory for High-Efficient Preparation of Biopesticide, School of Forestry and Biotechnology, Zhejiang A&F University, 311300, Hangzhou, People's Republic of China
| | - Xiu Su
- Collaborative Innovation Center of Zhejiang Green Pesticide, National Joint Local Engineering Laboratory for High-Efficient Preparation of Biopesticide, School of Forestry and Biotechnology, Zhejiang A&F University, 311300, Hangzhou, People's Republic of China
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Zhou X, Chen S, Lu F, Guo K, Huang L, Su X, Chen Y. Nematotoxicity of a Cyt-like protein toxin from Conidiobolus obscurus (Entomophthoromycotina) on the pine wood nematode Bursaphelenchus xylophilus. PEST MANAGEMENT SCIENCE 2021; 77:686-692. [PMID: 32841476 DOI: 10.1002/ps.6060] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 08/04/2020] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND The pine wood nematode Bursaphelenchus xylophilus is a destructive pest on Pinus trees and lacks effective control measures. The present study identified a novel nematotoxic cytolytic (Cyt)-like protein originating from the entomopathogenic fungus Conidiobolus obscurus. RESULTS The protein was successfully purified using heterologous expression in Escherichia coli and affinity chromatography. N-hydroxysuccinimide-rhodamine-labeled Cyt-like protein was used to establish the route of toxin uptake, and revealed that the toxin can enter the nematode via the stylet. In bioassays, the purified protein had high nematicide activity against B. xylophilus, with a median lethal concentration at 24 h of 15.8 and 29.4 μg mL-1 for juveniles and adults, respectively. Compared with the deionized water control, fecundity, thrashing, and egg hatching were significantly reduced by 97%, 98%, and 83%, respectively, with 40 μg mL-1 Cyt-like protein at 24-36 h. Staining with Oil-Red-O showed a decrease in large lipid droplet formation in the protein-treated adult nematodes. CONCLUSION The Cyt-like protein toxin possesses high nematicide activity against B. xylophilus with effects on nematode vitality and fecundity. The potential exists to use the Cyt-like protein for the control of B. xylophilus.
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Affiliation(s)
- Xiang Zhou
- Collaborative Innovation Center of Zhejiang Green Pesticide, State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, People's Republic of China
| | - Shani Chen
- Collaborative Innovation Center of Zhejiang Green Pesticide, State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, People's Republic of China
| | - Feng Lu
- Collaborative Innovation Center of Zhejiang Green Pesticide, State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, People's Republic of China
| | - Kai Guo
- Collaborative Innovation Center of Zhejiang Green Pesticide, State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, People's Republic of China
| | - Linlin Huang
- Collaborative Innovation Center of Zhejiang Green Pesticide, State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, People's Republic of China
| | - Xiu Su
- Collaborative Innovation Center of Zhejiang Green Pesticide, State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, People's Republic of China
| | - Ye Chen
- Collaborative Innovation Center of Zhejiang Green Pesticide, State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, People's Republic of China
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López-Molina S, do Nascimento NA, Silva-Filha MHNL, Guerrero A, Sánchez J, Pacheco S, Gill SS, Soberón M, Bravo A. In vivo nanoscale analysis of the dynamic synergistic interaction of Bacillus thuringiensis Cry11Aa and Cyt1Aa toxins in Aedes aegypti. PLoS Pathog 2021; 17:e1009199. [PMID: 33465145 PMCID: PMC7846010 DOI: 10.1371/journal.ppat.1009199] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 01/29/2021] [Accepted: 11/30/2020] [Indexed: 12/22/2022] Open
Abstract
The insecticidal Cry11Aa and Cyt1Aa proteins are produced by Bacillus thuringiensis as crystal inclusions. They work synergistically inducing high toxicity against mosquito larvae. It was proposed that these crystal inclusions are rapidly solubilized and activated in the gut lumen, followed by pore formation in midgut cells killing the larvae. In addition, Cyt1Aa functions as a Cry11Aa binding receptor, inducing Cry11Aa oligomerization and membrane insertion. Here, we used fluorescent labeled crystals, protoxins or activated toxins for in vivo localization at nano-scale resolution. We show that after larvae were fed solubilized proteins, these proteins were not accumulated inside the gut and larvae were not killed. In contrast, if larvae were fed soluble non-toxic mutant proteins, these proteins were found inside the gut bound to gut-microvilli. Only feeding with crystal inclusions resulted in high larval mortality, suggesting that they have a role for an optimal intoxication process. At the macroscopic level, Cry11Aa completely degraded the gastric caeca structure and, in the presence of Cyt1Aa, this effect was observed at lower toxin-concentrations and at shorter periods. The labeled Cry11Aa crystal protein, after midgut processing, binds to the gastric caeca and posterior midgut regions, and also to anterior and medium regions where it is internalized in ordered "net like" structures, leading finally to cell break down. During synergism both Cry11Aa and Cyt1Aa toxins showed a dynamic layered array at the surface of apical microvilli, where Cry11Aa is localized in the lower layer closer to the cell cytoplasm, and Cyt1Aa is layered over Cry11Aa. This array depends on the pore formation activity of Cry11Aa, since the non-toxic mutant Cry11Aa-E97A, which is unable to oligomerize, inverted this array. Internalization of Cry11Aa was also observed during synergism. These data indicate that the mechanism of action of Cry11Aa is more complex than previously anticipated, and may involve additional steps besides pore-formation activity.
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Affiliation(s)
- Samira López-Molina
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
| | | | | | - Adán Guerrero
- Laboratorio Nacional de Microscopía Avanzada, Instituto de Biotecnología, UNAM, Cuernavaca, Morelos, Mexico
| | - Jorge Sánchez
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
| | - Sabino Pacheco
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
| | - Sarjeet S. Gill
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, California, United States of America
| | - Mario Soberón
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
| | - Alejandra Bravo
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
- * E-mail:
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Potential for Bacillus thuringiensis and Other Bacterial Toxins as Biological Control Agents to Combat Dipteran Pests of Medical and Agronomic Importance. Toxins (Basel) 2020; 12:toxins12120773. [PMID: 33291447 PMCID: PMC7762171 DOI: 10.3390/toxins12120773] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 11/24/2020] [Accepted: 12/03/2020] [Indexed: 11/16/2022] Open
Abstract
The control of dipteran pests is highly relevant to humans due to their involvement in the transmission of serious diseases including malaria, dengue fever, Chikungunya, yellow fever, zika, and filariasis; as well as their agronomic impact on numerous crops. Many bacteria are able to produce proteins that are active against insect species. These bacteria include Bacillus thuringiensis, the most widely-studied pesticidal bacterium, which synthesizes proteins that accumulate in crystals with insecticidal properties and which has been widely used in the biological control of insects from different orders, including Lepidoptera, Coleoptera, and Diptera. In this review, we summarize all the bacterial proteins, from B. thuringiensis and other entomopathogenic bacteria, which have described insecticidal activity against dipteran pests, including species of medical and agronomic importance.
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Baranek J, Pogodziński B, Szipluk N, Zielezinski A. TOXiTAXi: a web resource for toxicity of Bacillus thuringiensis protein compositions towards species of various taxonomic groups. Sci Rep 2020; 10:19767. [PMID: 33188218 PMCID: PMC7666212 DOI: 10.1038/s41598-020-75932-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/29/2020] [Indexed: 11/20/2022] Open
Abstract
Bioinsecticides consisting of different sets of Bacillus thuringiensis (Bt) Cry, Cyt and Vip toxins are broadly used in pest control. Possible interactions (synergistic, additive or antagonistic) between these proteins can not only influence the overall efficacy of certain Bt-based bioinsecticide, but also raise questions regarding environmental safety. Here, we assemble, summarize and analyze the outcomes of experiments published over 30 years, investigating combinatorial effects among Bt Cry, Cyt and Vip toxins. We collected the results on 118 various two-to-five-component combinations that have been bioassayed against 38 invertebrate species. Synergism, additive effect and antagonism was indicated in 54%, 32% and 14% of experiments, respectively. Synergism was noted most frequently for Cry/Cyt combinations, followed by Cyt/Vip and Cry/Cry. In Cry/Vip combinations, antagonism is more frequent and higher in magnitude compared to other categories. Despite a significant number of tested Bt toxin combinations, most of them have been bioassayed only against one pest species. To aid the research on Bt pesticidal protein activity, we present TOXiTAXi ( http://www.combio.pl/toxitaxi/ ), a universal database and a dedicated web tool to conveniently gather and analyze the existing and future bioassay results on biocidal activity of toxins against various taxonomic groups.
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Affiliation(s)
- Jakub Baranek
- Department of Microbiology, Faculty of Biology, Adam Mickiewicz University in Poznan, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland.
| | - Bartłomiej Pogodziński
- Department of Computational Biology, Faculty of Biology, Adam Mickiewicz University in Poznan, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland
| | - Norbert Szipluk
- Department of Microbiology, Faculty of Biology, Adam Mickiewicz University in Poznan, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland
| | - Andrzej Zielezinski
- Department of Computational Biology, Faculty of Biology, Adam Mickiewicz University in Poznan, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland
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Onofre J, Pacheco S, Torres-Quintero MC, Gill SS, Soberon M, Bravo A. The Cyt1Aa toxin from Bacillus thuringiensis inserts into target membranes via different mechanisms in insects, red blood cells, and lipid liposomes. J Biol Chem 2020; 295:9606-9617. [PMID: 32444494 DOI: 10.1074/jbc.ra120.013869] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/20/2020] [Indexed: 11/06/2022] Open
Abstract
Bacillus thuringiensis subsp. israelensis produces crystal inclusions composed of three-domain Cry proteins and cytolytic Cyt toxins, which are toxic to different mosquito larvae. A key component is the Cyt toxin, which synergizes the activity of the other Cry toxins, thereby resulting in high toxicity. The precise mechanism of action of Cyt toxins is still debated, and two models have been proposed: the pore formation model and the detergent effect. Here, we performed a systematic structural characterization of the Cyt toxin interaction with different membranes, including in Aedes aegypti larval brush border membrane vesicles, small unilamellar vesicle liposomes, and rabbit erythrocytes. We examined Cyt1Aa insertion into these membranes by analyzing fluorescence quenching in solution and in the membrane-bound state. For this purpose, we constructed several Cyt1Aa variants having substitutions with a single cysteine residue in different secondary structures, enabling Cys labeling with Alexa Fluor 488 for quenching analysis using I-soluble quencher in solution and in the membrane-bound state. We identified the Cyt1Aa residues exposed to the solvent upon membrane insertion, predicting a possible topology of the membrane-inserted toxin in the different membranes. Moreover, toxicity assays with these variants revealed that Cyt1Aa exerts its insecticidal activity and hemolysis through different mechanisms. We found that Cyt1Aa exhibits variable interactions with each membrane system, with deeper insertion into mosquito larva membranes, supporting the pore formation model, whereas in the case of erythrocytes and small unilamellar vesicles, Cyt1Aa's insertion was more superficial, supporting the notion that a detergent effect underlies its hemolytic activity.
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Affiliation(s)
- Janette Onofre
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Sabino Pacheco
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Mary Carmen Torres-Quintero
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Sarjeet S Gill
- Cell Biology and Neuroscience Department, University of California, Riverside, California, USA
| | - Mario Soberon
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Alejandra Bravo
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
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Valtierra-de-Luis D, Villanueva M, Lai L, Williams T, Caballero P. Potential of Cry10Aa and Cyt2Ba, Two Minority δ-endotoxins Produced by Bacillus thuringiensis ser. israelensis, for the Control of Aedes aegypti Larvae. Toxins (Basel) 2020; 12:toxins12060355. [PMID: 32485828 PMCID: PMC7354544 DOI: 10.3390/toxins12060355] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/22/2020] [Accepted: 05/26/2020] [Indexed: 11/16/2022] Open
Abstract
Bacillus thuringiensis ser. israelensis (Bti) has been widely used as microbial larvicide for the control of many species of mosquitoes and blackflies. The larvicidal activity of Bti resides in Cry and Cyt δ-endotoxins present in the parasporal crystal of this pathogen. The insecticidal activity of the crystal is higher than the activities of the individual toxins, which is likely due to synergistic interactions among the crystal component proteins, particularly those involving Cyt1Aa. In the present study, Cry10Aa and Cyt2Ba were cloned from the commercial larvicide VectoBac-12AS® and expressed in the acrystalliferous Bt strain BMB171 under the cyt1Aa strong promoter of the pSTAB vector. The LC50 values for Aedes aegypti second instar larvae estimated at 24 hpi for these two recombinant proteins (Cry10Aa and Cyt2Ba) were 299.62 and 279.37 ng/mL, respectively. Remarkable synergistic mosquitocidal activity was observed between Cry10Aa and Cyt2Ba (synergistic potentiation of 68.6-fold) when spore + crystal preparations, comprising a mixture of both recombinant strains in equal relative concentrations, were ingested by A. aegypti larvae. This synergistic activity is among the most powerful described so far with Bt toxins and is comparable to that reported for Cyt1A when interacting with Cry4Aa, Cry4Ba or Cry11Aa. Synergistic mosquitocidal activity was also observed between the recombinant proteins Cyt2Ba and Cry4Aa, but in this case, the synergistic potentiation was 4.6-fold. In conclusion, although Cry10Aa and Cyt2Ba are rarely detectable or appear as minor components in the crystals of Bti strains, they represent toxicity factors with a high potential for the control of mosquito populations.
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Affiliation(s)
- Daniel Valtierra-de-Luis
- Departamento de Agronomía, Biotecnología y Alimentación, Universidad Pública de Navarra, 31006 Pamplona, Spain; (D.V.-d.-L.); (M.V.); (L.L.)
| | - Maite Villanueva
- Departamento de Agronomía, Biotecnología y Alimentación, Universidad Pública de Navarra, 31006 Pamplona, Spain; (D.V.-d.-L.); (M.V.); (L.L.)
- Bioinsectis SL, Avda Pamplona 123, 31192 Mutilva, Spain
| | - Liliana Lai
- Departamento de Agronomía, Biotecnología y Alimentación, Universidad Pública de Navarra, 31006 Pamplona, Spain; (D.V.-d.-L.); (M.V.); (L.L.)
| | | | - Primitivo Caballero
- Departamento de Agronomía, Biotecnología y Alimentación, Universidad Pública de Navarra, 31006 Pamplona, Spain; (D.V.-d.-L.); (M.V.); (L.L.)
- Bioinsectis SL, Avda Pamplona 123, 31192 Mutilva, Spain
- Institute for Multidisciplinary Applied Biology Research (IMAB), Universidad Pública de Navarra, 31006 Mutilva, Spain
- Correspondence:
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11
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Anaya P, Onofre J, Torres-Quintero MC, Sánchez J, Gill SS, Bravo A, Soberón M. Oligomerization is a key step for Bacillus thuringiensis Cyt1Aa insecticidal activity but not for toxicity against red blood cells. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 119:103317. [PMID: 31978588 PMCID: PMC7245338 DOI: 10.1016/j.ibmb.2020.103317] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 01/08/2020] [Accepted: 01/10/2020] [Indexed: 06/10/2023]
Abstract
Bacillus thuringiensis (Bt) Cyt1Aa toxin shows toxicity to mosquitoes, to certain coleopteran pests and also to red blood cells (RBC). However, its mode of action in the different target cells is not well defined. This protein is a single α-β domain pore-forming toxin, where a β sheet is wrapped by two α-helices layers. The Cyt1Aa α-helix hairpin in the N-terminal has been proposed to be involved in initial membrane binding and oligomerization, while the β sheet inserts into the membrane to form a pore that lyze the cells. To determine the role of the N-terminal α-helix hairpin region of Cyt1Aa in its mode of action, we characterized different single point mutations located in helices α-1 and α-2. Eight cysteine substitutions in different residues were produced in Bt, and we found that three of them: Cyt1AaA65C, Cyt1AaL85C and Cyt1AaN89C, lost insecticidal toxicity against Aedes aegypti larvae but retained similar or increased hemolytic activity towards rabbit RBC. Analysis of toxin binding and oligomerization using Ae. aegypti midgut brush border membrane vesicles showed that the three Cyt1Aa mutants non-toxic to Ae. aegypti were affected in oligomerization. However, these mutants were still hemolytic. Our data shows that oligomerization of Cyt1Aa toxin is essential for its toxicity to Ae. aegypti but not for its toxicity against RBC indicating that the mode of action of Cyt1Aa is different in these distinct target membranes.
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Affiliation(s)
- Paulina Anaya
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, Morelos, 62250, Mexico
| | - Janette Onofre
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, Morelos, 62250, Mexico
| | - Mary Carmen Torres-Quintero
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, Morelos, 62250, Mexico
| | - Jorge Sánchez
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, Morelos, 62250, Mexico
| | - Sarjeet S Gill
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, 92521, USA
| | - Alejandra Bravo
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, Morelos, 62250, Mexico
| | - Mario Soberón
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, Morelos, 62250, Mexico.
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12
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Functional Bacillus thuringiensis Cyt1Aa Is Necessary To Synergize Lysinibacillus sphaericus Binary Toxin (Bin) against Bin-Resistant and -Refractory Mosquito Species. Appl Environ Microbiol 2020; 86:AEM.02770-19. [PMID: 32005737 DOI: 10.1128/aem.02770-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 01/21/2020] [Indexed: 11/20/2022] Open
Abstract
The binary (Bin) toxin from Lysinibacillus sphaericus is effective to mosquito larvae, but its utilization is threatened by the development of insect resistance. Bin toxin is composed of the BinB subunit required for binding to midgut receptors and the BinA subunit that causes toxicity after cell internalization, mediated by BinB. Culex quinquefasciatus resistance to this toxin is caused by mutations that prevent expression of Bin toxin receptors in the midgut. Previously, it was shown that the Cyt1Aa toxin from Bacillus thuringiensis subsp. israelensis restores Bin toxicity to Bin-resistant C. quinquefasciatus and to Aedes aegypti larvae, which are naturally devoid of functional Bin receptors. Our goal was to elucidate the mechanism involved in Cyt1Aa synergism with Bin in such larvae. In vivo assays showed that the mixture of Bin toxin, or its BinA subunit, with Cyt1Aa was effective to kill resistant larvae. However, no specific binding interaction between Cyt1Aa and the Bin toxin, or its subunits, was observed. The synergy between Cyt1Aa and Bin toxins is dependent on functional Cyt1Aa, as demonstrated by using the nontoxic Cyt1AaV122E mutant toxin affected in oligomerization and membrane insertion, which was unable to synergize Bin toxicity in resistant larvae. The synergism correlated with the internalization of Bin or BinA into anterior and medium midgut epithelial cells, which occurred only in larvae treated with wild-type Cyt1Aa toxin. This toxin is able to overcome failures in the binding step involving BinB receptor by allowing the internalization of Bin toxin, or its BinA subunit, into the midgut cells.IMPORTANCE One promising management strategy for mosquito control is the utilization of a mixture of L. sphaericus and B. thuringiensis subsp. israelensis insecticidal toxins. From this set, Bin and Cyt1Aa toxins synergize and display toxicity to resistant C. quinquefasciatus and to A. aegypti larvae, whose midgut cells lack Bin toxin receptors. Our data set provides evidence that functional Cyt1Aa is essential for internalization of Bin or its BinA subunit into such cells, but binding interaction between Bin and Cyt1Aa is not observed. Thus, this mechanism contrasts with that for the synergy between Cyt1Aa and the B. thuringiensis subsp. israelensis Cry toxins, where active Cyt1Aa is not necessary but a specific binding between Cry and Cyt1Aa is required. Our study established the initial molecular basis of the synergy between Bin and Cyt1Aa, and these findings enlarge our knowledge of their mode of action, which could help to develop improved strategies to cope with insect resistance.
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Serial femtosecond crystallography on in vivo-grown crystals drives elucidation of mosquitocidal Cyt1Aa bioactivation cascade. Nat Commun 2020; 11:1153. [PMID: 32123169 PMCID: PMC7052140 DOI: 10.1038/s41467-020-14894-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 02/08/2020] [Indexed: 11/08/2022] Open
Abstract
Cyt1Aa is the one of four crystalline protoxins produced by mosquitocidal bacterium Bacillus thuringiensis israelensis (Bti) that has been shown to delay the evolution of insect resistance in the field. Limiting our understanding of Bti efficacy and the path to improved toxicity and spectrum has been ignorance of how Cyt1Aa crystallizes in vivo and of its mechanism of toxicity. Here, we use serial femtosecond crystallography to determine the Cyt1Aa protoxin structure from sub-micron-sized crystals produced in Bti. Structures determined under various pH/redox conditions illuminate the role played by previously uncharacterized disulfide-bridge and domain-swapped interfaces from crystal formation in Bti to dissolution in the larval mosquito midgut. Biochemical, toxicological and biophysical methods enable the deconvolution of key steps in the Cyt1Aa bioactivation cascade. We additionally show that the size, shape, production yield, pH sensitivity and toxicity of Cyt1Aa crystals grown in Bti can be controlled by single atom substitution. Bacillus thuringiensis israelensis (Bti) produces the naturally-crystalline proteinaceous toxin Cyt1Aa that is toxic to mosquito larvae. Here the authors grow recombinant nanocrystals of the Cyt1Aa protoxin in vivo and use serial femtosecond crystallography to determine its structure at different redox and pH conditions and by combining their structural data with further biochemical, toxicological and biophysical analyses provide mechanistic insights into the Cyt1Aa bioactivation cascade.
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14
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Khorramnejad A, Domínguez-Arrizabalaga M, Caballero P, Escriche B, Bel Y. Study of the Bacillus thuringiensis Cry1Ia Protein Oligomerization Promoted by Midgut Brush Border Membrane Vesicles of Lepidopteran and Coleopteran Insects, or Cultured Insect Cells. Toxins (Basel) 2020; 12:toxins12020133. [PMID: 32098045 PMCID: PMC7076784 DOI: 10.3390/toxins12020133] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/31/2020] [Accepted: 02/19/2020] [Indexed: 12/18/2022] Open
Abstract
Bacillus thuringiensis (Bt) produces insecticidal proteins that are either secreted during the vegetative growth phase or accumulated in the crystal inclusions (Cry proteins) in the stationary phase. Cry1I proteins share the three domain (3D) structure typical of crystal proteins but are secreted to the media early in the stationary growth phase. In the generally accepted mode of action of 3D Cry proteins (sequential binding model), the formation of an oligomer (tetramer) has been described as a major step, necessary for pore formation and subsequent toxicity. To know if this could be extended to Cry1I proteins, the formation of Cry1Ia oligomers was studied by Western blot, after the incubation of trypsin activated Cry1Ia with insect brush border membrane vesicles (BBMV) or insect cultured cells, using Cry1Ab as control. Our results showed that Cry1Ia oligomers were observed only after incubation with susceptible coleopteran BBMV, but not following incubation with susceptible lepidopteran BBMV or non-susceptible Sf21 insect cells, while Cry1Ab oligomers were persistently detected after incubation with all insect tissues tested, regardless of its host susceptibility. The data suggested oligomerization may not necessarily be a requirement for the toxicity of Cry1I proteins.
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Affiliation(s)
- Ayda Khorramnejad
- Departamento de Genética/ERI BioTecMed, Universitat de València, Burjassot, 46100 València, Spain; (A.K.); (B.E.)
- Department of Plant Protection, College of Agriculture and Natural Resources, University of Tehran, Karaj 31578-77871, Alborz, Iran
| | - Mikel Domínguez-Arrizabalaga
- Departamento de Agronomía, Biotecnología y Alimentación, Universidad Pública de Navarra, Pamplona, 31006 Navarra, Spain; (M.D.-A.); (P.C.)
| | - Primitivo Caballero
- Departamento de Agronomía, Biotecnología y Alimentación, Universidad Pública de Navarra, Pamplona, 31006 Navarra, Spain; (M.D.-A.); (P.C.)
| | - Baltasar Escriche
- Departamento de Genética/ERI BioTecMed, Universitat de València, Burjassot, 46100 València, Spain; (A.K.); (B.E.)
| | - Yolanda Bel
- Departamento de Genética/ERI BioTecMed, Universitat de València, Burjassot, 46100 València, Spain; (A.K.); (B.E.)
- Correspondence:
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15
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Sato R, Adegawa S, Li X, Tanaka S, Endo H. Function and Role of ATP-Binding Cassette Transporters as Receptors for 3D-Cry Toxins. Toxins (Basel) 2019; 11:E124. [PMID: 30791434 PMCID: PMC6409751 DOI: 10.3390/toxins11020124] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/13/2019] [Accepted: 02/15/2019] [Indexed: 12/20/2022] Open
Abstract
When ABC transporter family C2 (ABCC2) and ABC transporter family B1 (ABCB1) were heterologously expressed in non-susceptible cultured cells, the cells swelled in response to Cry1A and Cry3 toxins, respectively. Consistent with the notion that 3D-Cry toxins form cation-permeable pores, Bombyx mori ABCC2 (BmABCC2) facilitated cation-permeable pore formation by Cry1A when expressed in Xenopus oocytes. Furthermore, BmABCC2 had a high binding affinity (KD) to Cry1Aa of 3.1 × 10-10 M. These findings suggest that ABC transporters, including ABCC2 and ABCB1, are functional receptors for 3D-Cry toxins. In addition, the Cry2 toxins most distant from Cry1A toxins on the phylogenetic tree used ABC transporter A2 as a receptor. These data suggest that 3D-Cry toxins use ABC transporters as receptors. In terms of inducing cell swelling, ABCC2 has greater activity than cadherin-like receptor. The pore opening of ABC transporters was hypothesized to be linked to their receptor function, but this was repudiated by experiments using mutants deficient in export activity. The synergistic relationship between ABCC2 and cadherin-like receptor explains their ability to cause resistance in one species of insect.
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Affiliation(s)
- Ryoichi Sato
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Naka 2-24-16, Koganei, Tokyo 184-8588, Japan.
| | - Satomi Adegawa
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Naka 2-24-16, Koganei, Tokyo 184-8588, Japan.
| | - Xiaoyi Li
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Naka 2-24-16, Koganei, Tokyo 184-8588, Japan.
| | - Shiho Tanaka
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Naka 2-24-16, Koganei, Tokyo 184-8588, Japan.
| | - Haruka Endo
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Naka 2-24-16, Koganei, Tokyo 184-8588, Japan.
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16
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Susceptible and mCry3A resistant corn rootworm larvae killed by a non-hemolytic Bacillus thuringiensis Cyt1Aa mutant. Sci Rep 2018; 8:17805. [PMID: 30546034 PMCID: PMC6292897 DOI: 10.1038/s41598-018-36205-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 11/16/2018] [Indexed: 11/12/2022] Open
Abstract
The western corn rootworm (WCR) Diabrotica virgifera virgifera causes substantial damage in corn. Genetically modified (GM) plants expressing some Bacillus thuringiensis (Bt) insecticidal Cry proteins efficiently controlled this pest. However, changes in WCR susceptibility to these Bt traits have evolved and identification of insecticidal proteins with different modes of action against WCR is necessary. We show here for the first time that Cyt1Aa from Bt exhibits toxicity against WCR besides to the dipteran Aedes aegypti larvae. Cyt1Aa is a pore-forming toxin that shows no cross-resistance with mosquitocidal Cry toxins. We characterized different mutations in helix α-A from Cyt1Aa. Two mutants (A61C and A59C) exhibited reduced or absent hemolytic activity but retained toxicity to A. aegypti larvae, suggesting that insecticidal and hemolytic activities of Cyt1Aa are independent activities. These mutants were still able to form oligomers in synthetic lipid vesicles and to synergize Cry11Aa toxicity. Remarkably, mutant A61C showed a five-fold increase insecticidal activity against mosquito and almost 11-fold higher activity against WCR. Cyt1Aa A61C mutant was as potent in killing WCR that were selected for resistance to mCry3A as it was against unselected WCR indicating that this toxin could be a useful resistance management option in the control of WCR.
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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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18
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New Cyt-like δ-endotoxins from Dickeya dadantii: structure and aphicidal activity. Sci Rep 2015; 5:8791. [PMID: 25740111 PMCID: PMC5390079 DOI: 10.1038/srep08791] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 02/04/2015] [Indexed: 12/11/2022] Open
Abstract
In the track of new biopesticides, four genes namely cytA, cytB, cytC and cytD encoding proteins homologous to Bacillus thuringiensis (Bt) Cyt toxins have been identified in the plant pathogenic bacteria Dickeya dadantii genome. Here we show that three Cyt-like δ-endotoxins from D. dadantii (CytA, CytB and CytC) are toxic to the pathogen of the pea aphid Acyrthosiphon pisum in terms of both mortality and growth rate. The phylogenetic analysis of the comprehensive set of Cyt toxins available in genomic databases shows that the whole family is of limited taxonomic occurrence, though in quite diverse microbial taxa. From a structure-function perspective the 3D structure of CytC and its backbone dynamics in solution have been determined by NMR. CytC adopts a cytolysin fold, structurally classified as a Cyt2-like protein. Moreover, the identification of a putative lipid binding pocket in CytC structure, which has been probably maintained in most members of the Cyt-toxin family, could support the importance of this lipid binding cavity for the mechanism of action of the whole family. This integrative approach provided significant insights into the evolutionary and functional history of D. dadantii Cyt toxins, which appears to be interesting leads for biopesticides.
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Allievi MC, Palomino MM, Prado Acosta M, Lanati L, Ruzal SM, Sánchez-Rivas C. Contribution of S-layer proteins to the mosquitocidal activity of Lysinibacillus sphaericus. PLoS One 2014; 9:e111114. [PMID: 25354162 PMCID: PMC4213006 DOI: 10.1371/journal.pone.0111114] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 09/26/2014] [Indexed: 11/25/2022] Open
Abstract
Lysinibacillus sphaericus strains belonging the antigenic group H5a5b produce spores with larvicidal activity against larvae of Culex mosquitoes. C7, a new isolated strain, which presents similar biochemical characteristics and Bin toxins in their spores as the reference strain 2362, was, however, more active against larvae of Culex mosquitoes. The contribution of the surface layer protein (S-layer) to this behaviour was envisaged since this envelope protein has been implicated in the pathogenicity of several bacilli, and we had previously reported its association to spores. Microscopic observation by immunofluorescence detection with anti S-layer antibody in the spores confirms their attachment. S-layers and BinA and BinB toxins formed high molecular weight multimers in spores as shown by SDS-PAGE and western blot detection. Purified S-layer from both L. sphaericus C7 and 2362 strain cultures was by itself toxic against Culex sp larvae, however, that from C7 strain was also toxic against Aedes aegypti. Synergistic effect between purified S-layer and spore-crystal preparations was observed against Culex sp. and Aedes aegypti larvae. This effect was more evident with the C7 strain. In silico analyses of the S-layer sequence suggest the presence of chitin-binding and hemolytic domains. Both biochemical characteristics were detected for both S-layers strains that must justify their contribution to pathogenicity.
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Affiliation(s)
- Mariana Claudia Allievi
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - María Mercedes Palomino
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - Mariano Prado Acosta
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - Leonardo Lanati
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - Sandra Mónica Ruzal
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - Carmen Sánchez-Rivas
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
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Bacillus thuringiensis subsp. israelensis and its dipteran-specific toxins. Toxins (Basel) 2014; 6:1222-43. [PMID: 24686769 PMCID: PMC4014730 DOI: 10.3390/toxins6041222] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 03/10/2014] [Accepted: 03/14/2014] [Indexed: 01/05/2023] Open
Abstract
Bacillus thuringiensis subsp. israelensis (Bti) is the first Bacillus thuringiensis to be found and used as an effective biological control agent against larvae of many mosquito and black fly species around the world. Its larvicidal activity resides in four major (of 134, 128, 72 and 27 kDa) and at least two minor (of 78 and 29 kDa) polypeptides encoded respectively by cry4Aa, cry4Ba, cry11Aa, cyt1Aa, cry10Aa and cyt2Ba, all mapped on the 128 kb plasmid known as pBtoxis. These six δ-endotoxins form a complex parasporal crystalline body with remarkably high, specific and different toxicities to Aedes, Culex and Anopheles larvae. Cry toxins are composed of three domains (perforating domain I and receptor binding II and III) and create cation-selective channels, whereas Cyts are composed of one domain that acts as well as a detergent-like membrane perforator. Despite the low toxicities of Cyt1Aa and Cyt2Ba alone against exposed larvae, they are highly synergistic with the Cry toxins and hence their combinations prevent emergence of resistance in the targets. The lack of significant levels of resistance in field mosquito populations treated for decades with Bti-bioinsecticide suggests that this bacterium will be an effective biocontrol agent for years to come.
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