1
|
Panteleri R, Anthousi A, Denecke S, Boaventura D, Nauen R, Vontas J. Transgenic Drosophila to Functionally Validate Fall Armyworm ABCC2 Mutations Conferring Bt Resistance. Toxins (Basel) 2023; 15:386. [PMID: 37368687 DOI: 10.3390/toxins15060386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 06/05/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith; Lepidoptera: Noctuidae) is an invasive agricultural pest with a global distribution, causing major crop losses annually. Its control strategies largely rely on chemical insecticides and transgenic crops expressing Bacillus thuringiensis insecticidal proteins (Cry and Vip toxins); however, the development of high resistance poses a significant issue. The ATP-binding cassette transporter C2 (ABCC2) has been linked to Cry toxin pore formation, acting as a receptor of some Cry toxins. Recently detected mutations in the SfABCC2 gene in extracellular loop 4 (ECL4) have been associated with Bt toxin resistance in FAW. In the present study, we expressed the SfABCC2 gene in Drosophila melanogaster, a species normally unaffected by the Bt toxins. We demonstrate that susceptibility can be introduced by the ectopic and tissue-specific expression of wildtype SfABCC2. Next, we introduced mutations into ECL4-both individually and in combination-that have been recently described in Brazilian FAW and functionally validated by toxicity bioassays against the foliar Bt product Xentari. Our results provide an efficient demonstration of the suitability of transgenic Drosophila for validating FAW ABCC2 resistance mutations in ECL4 against Bt toxins, and potential cross-resistance issues between closely related proteins that use ABCC2.
Collapse
Affiliation(s)
- Rafaela Panteleri
- Department of Biology, University of Crete, Vassilika Vouton, 71409 Heraklion, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 71409 Heraklion, Greece
| | - Amalia Anthousi
- Department of Biology, University of Crete, Vassilika Vouton, 71409 Heraklion, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 71409 Heraklion, Greece
| | - Shane Denecke
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 71409 Heraklion, Greece
- Department of Pathobiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Debora Boaventura
- Bayer AG, Crop Science Division, R&D, Pest Control, 40789 Monheim, Germany
| | - Ralf Nauen
- Bayer AG, Crop Science Division, R&D, Pest Control, 40789 Monheim, Germany
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 71409 Heraklion, Greece
- Pesticide Science Laboratory, Department of Crop Science, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece
| |
Collapse
|
2
|
Franz L, Raming K, Nauen R. Recombinant Expression of ABCC2 Variants Confirms the Importance of Mutations in Extracellular Loop 4 for Cry1F Resistance in Fall Armyworm. Toxins (Basel) 2022; 14:toxins14020157. [PMID: 35202184 PMCID: PMC8878193 DOI: 10.3390/toxins14020157] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/15/2022] [Accepted: 02/17/2022] [Indexed: 01/15/2023] Open
Abstract
Fall armyworm (FAW), Spodoptera frugiperda, is a highly destructive and invasive global noctuid pest. Its control is based on insecticide applications and Bacillus thuringiensis (Bt) insecticidal Cry toxins expressed in transgenic crops, such as Cry1F in Bt corn. Continuous selection pressure has resulted in populations that are resistant to Bt corn, particularly in Brazil. FAW resistance to Cry1F was recently shown to be conferred by mutations of ATP-binding cassette transporter C2 (ABCC2), but several mutations, particularly indels in extracellular loop 4 (ECL4), are not yet functionally validated. We addressed this knowledge gap by baculovirus-free insect cell expression of ABCC2 variants (and ABCC3) by electroporation technology and tested their response to Cry1F, Cry1A.105 and Cry1Ab. We employed a SYTOXTM orange cell viability test measuring ABCC2-mediated Bt toxin pore formation. In total, we tested seven different FAW ABCC2 variants mutated in ECL4, two mutants modified in nucleotide binding domain (NBD) 2, including a deletion mutant lacking NBD2, and S. frugiperda ABCC3. All tested ECL4 mutations conferred high resistance to Cry1F, but much less to Cry1A.105 and Cry1Ab, whereas mutations in NBD2 hardly affected Bt toxin activity. Our study confirms the importance of indels in ECL4 for Cry1F resistance in S. frugiperda ABCC2.
Collapse
|
3
|
Fernandes FO, de Souza TD, Sanches AC, Dias NP, Desiderio JA, Polanczyk RA. Sub-lethal effects of a Bt-based bioinsecticide on the biological conditioning of Anticarsia gemmatalis. ECOTOXICOLOGY (LONDON, ENGLAND) 2021; 30:2071-2082. [PMID: 34549369 DOI: 10.1007/s10646-021-02476-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/01/2021] [Indexed: 06/13/2023]
Abstract
Bioinsecticides based on Bacillus thuringiensis (Bt) Berliner, 1915 are widely used to control lepidopteran in several crops. However, surviving insects exposed to the sub-lethal concentration of Bt-based bioinsecticides can suffer a multitude of effects on the biological conditioning known as hormesis. Here, we aimed to provide a clearer understanding of the biological conditioning of Anticarsia gemmatalis (Hübner, 1818), exposed to different concentrations of a Bt-based bioinsecticide, by assessing life table parameters over three generations. We defined five sub-lethal concentrations (LC5, LC10, LC15, LC20, and LC25) from the response curve estimate of A. gemmatalis. Deionized water was used as a control. We assessed the parameters of eggs-viability and the duration of the stages, incubation, larval, pre-pupal, pupal, adult, pre-oviposition and total biological cycle. Data were used to construct the fertility life table using the two-sex program. The survival curves showed greater variation in the proportion of individuals at each development stage using the LC25. The sub-lethal concentrations did not influence the incubation-eggs period, pre-pupal and pupal. However, the larval and adult stages using LC25 and LC10 were the most affected. Changes in sex ratio were observed using LC20 and LC5. The toxic effect of Bt-based bioinsecticide interfered mainly in the parameters of fertility, sex ratio, net reproduction rate (R0), and gross reproduction rate (GRR).
Collapse
Affiliation(s)
| | - Tamires Doroteo de Souza
- Department of Plant Protection, Paulista State University "Júlio de Mesquita Filho", Jaboticabal, Brazil
| | - Ariadne Costas Sanches
- Department of Biological and Health Sciences, Faculty of Philosophy, Sciences and Letters of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Naymã Pinto Dias
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, USA
| | - Janete Apparecida Desiderio
- Department of Biology Applied to Agriculture, Paulista State University "Júlio de Mesquita Filho", Jaboticabal, Brazil
| | - Ricardo Antonio Polanczyk
- Department of Plant Protection, Paulista State University "Júlio de Mesquita Filho", Jaboticabal, Brazil
| |
Collapse
|
4
|
Boaventura D, Ulrich J, Lueke B, Bolzan A, Okuma D, Gutbrod O, Geibel S, Zeng Q, Dourado PM, Martinelli S, Flagel L, Head G, Nauen R. Molecular characterization of Cry1F resistance in fall armyworm, Spodoptera frugiperda from Brazil. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 116:103280. [PMID: 31740346 DOI: 10.1016/j.ibmb.2019.103280] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 11/05/2019] [Accepted: 11/12/2019] [Indexed: 05/21/2023]
Abstract
Fall armyworm, Spodoptera frugiperda (J.E. Smith) is a major lepidopteran pest of maize in Brazil and its control particularly relies on the use of genetically engineered crops expressing Bacillus thuringiensis (Bt) toxins such as Cry1F. However, control failures compromising the efficacy of this technology have been reported in many regions in Brazil, but the mechanism of Cry1F resistance in Brazilian fall armyworm populations remained elusive. Here we investigated the molecular mechanism of Cry1F resistance in two field-collected strains of S. frugiperda from Brazil exhibiting high levels of Cry1F resistance. We first rigorously evaluated several candidate reference genes for normalization of gene expression data across strains, larval instars and gut tissues, and identified ribosomal proteins L10, L17 and RPS3A to be most suitable. We then investigated the expression pattern of ten potential Bt toxin receptors/enzymes in both neonates and 2nd instar gut tissue of Cry1F resistant fall armyworm strains compared to a susceptible strain. Next we sequenced the ATP-dependent Binding Cassette subfamily C2 gene (ABCC2) and identified three mutated sites present in ABCC2 of both Cry1F resistant strains: two of them, a GY deletion (positions 788-789) and a P799 K/R amino acid substitution, located in a conserved region of ABCC2 extracellular loop 4 (EC4) and another amino acid substitution, G1088D, but in a less conserved region. We further characterized the role of the novel mutations present in EC4 by functionally expressing both wild type and mutated ABCC2 transporters in insect cell lines, and confirmed a critical role of both sites for Cry1F binding by cell viability assays. Finally, we assessed the frequency of the mutant alleles by pooled population sequencing and pyrosequencing in 40 fall armyworm populations collected from maize fields in different regions in Brazil. We found that the GY deletion being present at high frequency. However we also observed many rare alleles which disrupt residues between sites 783-799, and their diversity and abundance in field collected populations lends further support to the importance of the EC4 domain for Cry1F toxicity.
Collapse
Affiliation(s)
- Debora Boaventura
- Institute of Crop Science and Resource Conservation, University of Bonn, 53115, Bonn, Germany; Bayer AG, Crop Science, R&D, Alfred Nobel Str. 50, 40789, Monheim, Germany
| | - Julia Ulrich
- Bayer AG, Crop Science, R&D, Alfred Nobel Str. 50, 40789, Monheim, Germany
| | - Bettina Lueke
- Bayer AG, Crop Science, R&D, Alfred Nobel Str. 50, 40789, Monheim, Germany
| | - Anderson Bolzan
- Department of Entomology and Acarology, University of São Paulo, Piracicaba, São Paulo, Brazil
| | - Daniela Okuma
- Bayer S.A, Crop Science, Av. Dr. Roberto Moreira, 5005, Paulinia, SP, Brazil
| | - Oliver Gutbrod
- Bayer AG, Crop Science, R&D, Alfred Nobel Str. 50, 40789, Monheim, Germany
| | - Sven Geibel
- Bayer AG, Crop Science, R&D, Alfred Nobel Str. 50, 40789, Monheim, Germany
| | - Qin Zeng
- Bayer U.S, Crop Science, R&D, 700 Chesterfield Pkwy W, Chesterfield, MO, 63017, USA
| | - Patrick M Dourado
- Bayer S.A, Crop Science, R&D, Avenida Nacoes Unidas, São Paulo, Brazil
| | - Samuel Martinelli
- Bayer U.S, Crop Science, R&D, 700 Chesterfield Pkwy W, Chesterfield, MO, 63017, USA
| | - Lex Flagel
- Bayer U.S, Crop Science, R&D, 700 Chesterfield Pkwy W, Chesterfield, MO, 63017, USA
| | - Graham Head
- Bayer U.S, Crop Science, R&D, 700 Chesterfield Pkwy W, Chesterfield, MO, 63017, USA
| | - Ralf Nauen
- Bayer AG, Crop Science, R&D, Alfred Nobel Str. 50, 40789, Monheim, Germany.
| |
Collapse
|
5
|
Bacillus thuringiensis Cry1Da_7 and Cry1B.868 Protein Interactions with Novel Receptors Allow Control of Resistant Fall Armyworms, Spodoptera frugiperda (J.E. Smith). Appl Environ Microbiol 2019; 85:AEM.00579-19. [PMID: 31175187 PMCID: PMC6677855 DOI: 10.1128/aem.00579-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 05/30/2019] [Indexed: 01/07/2023] Open
Abstract
Two new modified Bacillus thuringiensis (Bt) proteins, Cry1Da_7 and Cry1B.868, with activity against fall armyworms (FAW), Spodoptera frugiperda (J.E. Smith), were evaluated for their potential to bind new insect receptors compared to proteins currently deployed as plant-incorporated protectants (PIPs) in row crops. Results from resistant insect bioassays, disabled insecticidal protein (DIP) bioassays, and cell-based assays using insect cells expressing individual receptors demonstrate that receptor utilizations of the newly modified Cry1Da_7 and Cry1B.868 proteins are distinct from each other and from those of commercially available Bt proteins such as Cry1F, Cry1A.105, Cry2Ab, and Vip3A. Accordingly, these two proteins target different insect proteins in FAW midgut cells and when pyramided together should provide durability in the field against this economically important pest.IMPORTANCE There is increased concern with the development of resistance to insecticidal proteins currently expressed in crop plants, especially against high-resistance-risk pests such as fall armyworm (FAW), Spodoptera frugiperda, a maize pest that already has developed resistance to Bacillus thuringiensis (Bt) proteins such as Cry1F. Lepidopteran-specific proteins that bind new insect receptors will be critical in managing current Cry1F-resistant FAW and delaying future resistance development. Results from resistant insect assays, disabled insecticidal protein (DIP) bioassays, and cell-based assays using insect cells expressing individual receptors demonstrate that target receptors of the Cry1Da_7 and Cry1B.868 proteins are different from each other and from those of commercially available Bt proteins such as Cry1F, Cry1A.105, Cry2Ab, and Vip3A. Therefore, pyramiding these two new proteins in maize will provide durable control of this economically important pest in production agriculture.
Collapse
|