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Farhan Y, Smith JL, Sovic MG, Michel AP. Genetic mutations linked to field-evolved Cry1Fa-resistance in the European corn borer, Ostrinia nubilalis. Sci Rep 2023; 13:8081. [PMID: 37202428 DOI: 10.1038/s41598-023-35252-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 05/15/2023] [Indexed: 05/20/2023] Open
Abstract
Transgenic corn, Zea mays (L.), expressing insecticidal toxins such as Cry1Fa, from Bacillus thuringiensis (Bt corn) targeting Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae) resulted in over 20 years of management success. The first case of practical field-evolved resistance by O. nubilalis to a Bt corn toxin, Cry1Fa, was discovered in Nova Scotia, Canada, in 2018. Laboratory-derived Cry1Fa-resistance by O. nubilalis was linked to a genome region encoding the ATP Binding Cassette subfamily C2 (ABCC2) gene; however, the involvement of ABCC2 and specific mutations in the gene leading to resistance remain unknown. Using a classical candidate gene approach, we report on O. nubilalis ABCC2 gene mutations linked to laboratory-derived and field-evolved Cry1Fa-resistance. Using these mutations, a DNA-based genotyping assay was developed to test for the presence of the Cry1Fa-resistance alleles in O. nubilalis strains collected in Canada. Screening data provide strong evidence that field-evolved Cry1Fa-resistance in O. nubilalis maps to the ABCC2 gene and demonstrates the utility of this assay for detecting the Cry1Fa resistance allele in O. nubilalis. This study is the first to describe mutations linked to Bt resistance in O. nubilalis and provides a DNA-based detection method that can be used for monitoring.
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Affiliation(s)
- Yasmine Farhan
- Department of Plant Agriculture, University of Guelph, Ridgetown Campus, Ridgetown, ON, Canada.
| | - Jocelyn L Smith
- Department of Plant Agriculture, University of Guelph, Ridgetown Campus, Ridgetown, ON, Canada
| | - Michael G Sovic
- Infectious Diseases Institute, The Ohio State University, Pickerington, OH, USA
| | - Andrew P Michel
- Department of Entomology, The Ohio State University, Wooster, OH, USA
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Wang X, Xu Y, Huang J, Jin W, Yang Y, Wu Y. CRISPR-Mediated Knockout of the ABCC2 Gene in Ostrinia furnacalis Confers High-Level Resistance to the Bacillus thuringiensis Cry1Fa Toxin. Toxins (Basel) 2020; 12:toxins12040246. [PMID: 32290427 PMCID: PMC7232378 DOI: 10.3390/toxins12040246] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/06/2020] [Accepted: 04/09/2020] [Indexed: 12/28/2022] Open
Abstract
The adoption of transgenic crops expressing Bacillus thuringiensis (Bt) insecticidal crystalline (Cry) proteins has reduced insecticide application, increased yields, and contributed to food safety worldwide. However, the efficacy of transgenic Bt crops is put at risk by the adaptive resistance evolution of target pests. Previous studies indicate that resistance to Bacillus thuringiensis Cry1A and Cry1F toxins was genetically linked with mutations of ATP-binding cassette (ABC) transporter subfamily C gene ABCC2 in at least seven lepidopteran insects. Several strains selected in the laboratory of the Asian corn borer, Ostrinia furnacalis, a destructive pest of corn in Asian Western Pacific countries, developed high levels of resistance to Cry1A and Cry1F toxins. The causality between the O. furnacalisABCC2 (OfABCC2) gene and resistance to Cry1A and Cry1F toxins remains unknown. Here, we successfully generated a homozygous strain (OfC2-KO) of O. furnacalis with an 8-bp deletion mutation of ABCC2 by the CRISPR/Cas9 approach. The 8-bp deletion mutation results in a frame shift in the open reading frame of transcripts, which produced a predicted protein truncated in the TM4-TM5 loop region. The knockout strain OfC2-KO showed much more than a 300-fold resistance to Cry1Fa, and low levels of resistance to Cry1Ab and Cry1Ac (<10-fold), but no significant effects on the toxicities of Cry1Aa and two chemical insecticides (abamectin and chlorantraniliprole), compared to the background NJ-S strain. Furthermore, we found that the Cry1Fa resistance was autosomal, recessive, and significantly linked with the 8-bp deletion mutation of OfABCC2 in the OfC2-KO strain. In conclusion, in vivo functional investigation demonstrates the causality of the OfABCC2 truncating mutation with high-level resistance to the Cry1Fa toxin in O. furnacalis. Our results suggest that the OfABCC2 protein might be a functional receptor for Cry1Fa and reinforces the association of this gene to the mode of action of the Cry1Fa toxin.
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Affiliation(s)
| | | | | | | | | | - Yidong Wu
- Correspondence: ; Tel.: +86-25-8439-6062
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Kozak GM, Wadsworth CB, Kahne SC, Bogdanowicz SM, Harrison RG, Coates BS, Dopman EB. A combination of sexual and ecological divergence contributes to rearrangement spread during initial stages of speciation. Mol Ecol 2017. [DOI: 10.111/mwc.1403610.1111/mec.14036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Genevieve M. Kozak
- Department of Biology Tufts University 200 Boston Ave. Ste. 4700 Medford MA 02155 USA
| | - Crista B. Wadsworth
- Department of Biology Tufts University 200 Boston Ave. Ste. 4700 Medford MA 02155 USA
- Harvard TH Chan School of Public Health 677 Huntington Ave. Boston MA 02115 USA
| | - Shoshanna C. Kahne
- Department of Biology Tufts University 200 Boston Ave. Ste. 4700 Medford MA 02155 USA
| | - Steven M. Bogdanowicz
- Department of Ecology and Evolutionary Biology Cornell University 215 Tower Road Ithaca NY 14853 USA
| | - Richard G. Harrison
- Department of Ecology and Evolutionary Biology Cornell University 215 Tower Road Ithaca NY 14853 USA
| | - Brad S. Coates
- Corn Insects and Crop Genetics Research Unit USDA‐ARS Iowa State University 103 Genetics Laboratory Ames IA 50011 USA
| | - Erik B. Dopman
- Department of Biology Tufts University 200 Boston Ave. Ste. 4700 Medford MA 02155 USA
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Kozak GM, Wadsworth CB, Kahne SC, Bogdanowicz SM, Harrison RG, Coates BS, Dopman EB. A combination of sexual and ecological divergence contributes to rearrangement spread during initial stages of speciation. Mol Ecol 2017; 26:2331-2347. [PMID: 28141898 DOI: 10.1111/mec.14036] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Revised: 12/12/2016] [Accepted: 01/10/2017] [Indexed: 01/04/2023]
Abstract
Chromosomal rearrangements between sympatric species often contain multiple loci contributing to assortative mating, local adaptation and hybrid sterility. When and how these associations arise during the process of speciation remains a subject of debate. Here, we address the relative roles of local adaptation and assortative mating on the dynamics of rearrangement evolution by studying how a rearrangement covaries with sexual and ecological trait divergence within a species. Previously, a chromosomal rearrangement that suppresses recombination on the Z (sex) chromosome was identified in European corn borer moths (Ostrinia nubilalis). We further characterize this recombination suppressor and explore its association with variation in sex pheromone communication and seasonal ecological adaptation in pairs of populations that are divergent in one or both of these characteristics. Direct estimates of recombination suppression in pedigree mapping families indicated that more than 39% of the Z chromosome (encompassing up to ~10 megabases and ~300 genes) resides within a nonrecombining unit, including pheromone olfactory receptor genes and a major quantitative trait locus that contributes to ecotype differences (Pdd). Combining direct and indirect estimates of recombination suppression, we found that the rearrangement was occasionally present between sexually isolated strains (E vs. Z) and between divergent ecotypes (univoltine vs. bivoltine). However, it was only consistently present when populations differed in both sexual and ecological traits. Our results suggest that independent of the forces that drove the initial establishment of the rearrangement, a combination of sexual and ecological divergence is required for rearrangement spread during speciation.
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Affiliation(s)
- Genevieve M Kozak
- Department of Biology, Tufts University, 200 Boston Ave. Ste. 4700, Medford, MA, 02155, USA
| | - Crista B Wadsworth
- Department of Biology, Tufts University, 200 Boston Ave. Ste. 4700, Medford, MA, 02155, USA.,Harvard TH Chan School of Public Health, 677 Huntington Ave., Boston, MA, 02115, USA
| | - Shoshanna C Kahne
- Department of Biology, Tufts University, 200 Boston Ave. Ste. 4700, Medford, MA, 02155, USA
| | - Steven M Bogdanowicz
- Department of Ecology and Evolutionary Biology, Cornell University, 215 Tower Road, Ithaca, NY, 14853, USA
| | - Richard G Harrison
- Department of Ecology and Evolutionary Biology, Cornell University, 215 Tower Road, Ithaca, NY, 14853, USA
| | - Brad S Coates
- Corn Insects and Crop Genetics Research Unit, USDA-ARS, Iowa State University, 103 Genetics Laboratory, Ames, IA, 50011, USA
| | - Erik B Dopman
- Department of Biology, Tufts University, 200 Boston Ave. Ste. 4700, Medford, MA, 02155, USA
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Vélez AM, Vellichirammal NN, Jurat-Fuentes JL, Siegfried BD. Cry1F resistance among lepidopteran pests: a model for improved resistance management? CURRENT OPINION IN INSECT SCIENCE 2016; 15:116-124. [PMID: 27436741 DOI: 10.1016/j.cois.2016.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/15/2016] [Accepted: 04/18/2016] [Indexed: 06/06/2023]
Abstract
The Cry1Fa protein from the bacterium Bacillus thuringiensis (Bt) is known for its potential to control lepidopteran pests, especially through transgenic expression in maize and cotton. The maize event TC1507 expressing the cry1Fa toxin gene became commercially available in the United States in 2003 for the management of key lepidopteran pests including the European corn borer, Ostrinia nubilalis, and the fall armyworm, Spodoptera frugiperda. A high-dose/refuge strategy has been widely adopted to delay evolution of resistance to event TC1507 and other transgenic Bt crops. Efficacy of this strategy depends on the crops expressing a high dose of the Bt toxin to targeted pests and adjacent refuges of non-Bt host plants serving as a source of abundant susceptible insects. While this strategy has proved effective in delaying O. nubilalis resistance, field-evolved resistance to event TC1507 has been reported in S. frugiperda populations in Puerto Rico, Brazil, and the southeastern United States. This paper examines available information on resistance to Cry1Fa in O. nubilalis and S. frugiperda and discusses how this information identifies opportunities to refine resistance management recommendations for Bt maize.
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Affiliation(s)
- Ana M Vélez
- University of Nebraska-Lincoln, Department of Entomology, 103 Entomology Hall, Lincoln, NE 68583-0816, United States.
| | - Neetha Nanoth Vellichirammal
- University of Nebraska-Lincoln, Department of Entomology, 103 Entomology Hall, Lincoln, NE 68583-0816, United States
| | - Juan Luis Jurat-Fuentes
- University of Tennessee, Department of Entomology and Plant Pathology, Plant Biotechnology Building, Knoxville, TN 37996, United States
| | - Blair D Siegfried
- University of Florida, Entomology and Nematology Department, Charles Steinmetz Hall, PO Box 110620, Gainesville, FL 32611-0620, United States
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Coates BS, Siegfried BD. Linkage of an ABCC transporter to a single QTL that controls Ostrinia nubilalis larval resistance to the Bacillus thuringiensis Cry1Fa toxin. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2015; 63:86-96. [PMID: 26093031 DOI: 10.1016/j.ibmb.2015.06.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 06/02/2015] [Accepted: 06/04/2015] [Indexed: 06/04/2023]
Abstract
Field evolved resistance of insect populations to Bacillus thuringiensis (Bt) crystalline (Cry) toxins expressed by crop plants has resulted in reduced control of insect feeding damage to field crops, and threatens the sustainability of Bt transgenic technologies. A single quantitative trait locus (QTL) that determines resistance in Ostrinia nubilalis larvae capable of surviving on reproductive stage transgenic corn that express the Bt Cry1Fa toxin was previously mapped to linkage group 12 (LG12) in a backcross pedigree. Fine mapping with high-throughput single nucleotide polymorphism (SNP) anchor markers, a candidate ABC transporter (abcc2) marker, and de novo mutations predicted from a genotyping-by-sequencing (GBS) data redefined a 268.8 cM LG12. The single QTL on LG12 spanned an approximate 46.1 cM region, in which marker 02302.286 and abcc2 were ≤ 2.81 cM, and the GBS marker 697 was an estimated 1.89 cM distant from the causal genetic factor. This positional mapping data showed that an O. nubilalis genome region encoding an abcc2 transporter is in proximity to a single QTL involved in the inheritance of Cry1F resistance, and will assist in the future identification the mutation(s) involved with this phenotype.
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Affiliation(s)
- Brad S Coates
- USDA-ARS, Corn Insects & Crop Genetics Research Unit, Genetics Laboratory, Iowa State University, Ames, IA 50011, USA; Department of Entomology, Iowa State University, Ames, IA 50011, USA.
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Nanoth Vellichirammal N, Wang H, Eyun SI, Moriyama EN, Coates BS, Miller NJ, Siegfried BD. Transcriptional analysis of susceptible and resistant European corn borer strains and their response to Cry1F protoxin. BMC Genomics 2015. [PMID: 26220297 PMCID: PMC4518661 DOI: 10.1186/s12864-015-1751-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Background Despite a number of recent reports of insect resistance to transgenic crops expressing insecticidal toxins from Bacillus thuringiensis (Bt), little is known about the mechanism of resistance to these toxins. The purpose of this study is to identify genes associated with the mechanism of Cry1F toxin resistance in European corn borer (Ostrinia nubilalis Hübner). For this, we compared the global transcriptomic response of laboratory selected resistant and susceptible O. nubilalis strain to Cry1F toxin. We further identified constitutive transcriptional differences between the two strains. Results An O. nubilalis midgut transcriptome of 36,125 transcripts was assembled de novo from 106 million Illumina HiSeq and Roche 454 reads and used as a reference for estimation of differential gene expression analysis. Evaluation of gene expression profiles of midgut tissues from the Cry1F susceptible and resistant strains after toxin exposure identified a suite of genes that responded to the toxin in the susceptible strain (n = 1,654), but almost 20-fold fewer in the resistant strain (n = 84). A total of 5,455 midgut transcripts showed significant constitutive expression differences between Cry1F susceptible and resistant strains. Transcripts coding for previously identified Cry toxin receptors, cadherin and alkaline phosphatase and proteases were also differentially expressed in the midgut of the susceptible and resistant strains. Conclusions Our current study provides a valuable resource for further molecular characterization of Bt resistance and insect response to Cry1F toxin in O. nubilalis and other pest species. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1751-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Haichuan Wang
- Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE, USA.
| | - Seong-Il Eyun
- Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, USA.
| | - Etsuko N Moriyama
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, USA.
| | - Brad S Coates
- USDA-ARS, Corn Insects and Crop Genetics Research Unit, Ames, IA, USA.
| | - Nicholas J Miller
- Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE, USA.
| | - Blair D Siegfried
- Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE, USA.
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Siegfried BD, Hellmich RL. Understanding successful resistance management. GM CROPS & FOOD 2014; 3:184-93. [DOI: 10.4161/gmcr.20715] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Coates BS, Sumerford DV, Siegfried BD, Hellmich RL, Abel CA. Unlinked genetic loci control the reduced transcription of aminopeptidase N 1 and 3 in the European corn borer and determine tolerance to Bacillus thuringiensis Cry1Ab toxin. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2013; 43:1152-1160. [PMID: 24121099 DOI: 10.1016/j.ibmb.2013.09.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 09/03/2013] [Accepted: 09/16/2013] [Indexed: 06/02/2023]
Abstract
Transgenic expression of Bacillus thuringiensis (Bt) crystalline (Cry) toxins by crop plants result in reduced insect feeding damage, but sustainability is threatened by the development of resistance traits in target insect populations. We investigated Bt toxin resistance trait in a laboratory colony of the European corn borer, Ostrinia nubilalis, selected for increased survival when exposed to Cry1Ab and correlated survival on Cry1Ab toxin with a constitutive ∼146.2 ± 17.3-fold reduction in midgut aminopeptidase N1 (apn1) transcript levels. A 7.1 ± 1.9-fold reduction apn3 transcript level was also correlated with Cry1Ab resistance. Quantitative trait locus (QTL) mapping identified a single major genome region controlling Cry1Ab resistance on linkage group 24 (LG24), and a minor QTL on LG27. Both QTL were independent of apn1 and apn3 loci on LG02. Positional mapping identified genetic markers that may assist in the identification of causal gene(s) within QTL intervals. This study indicates that genetic factor(s) may act in trans to reduce both apn1 and apn3 expression in Cry1Ab resistant O. nubilalis larvae, and suggest that gene regulatory pathways can influence Bt resistance traits. These findings show that gene interactions (epistasis) may influence Bt resistance in target insect populations.
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Affiliation(s)
- Brad S Coates
- USDA-ARS, Corn Insect and Crop Genetics Research Unit, Genetics Laboratory, Iowa State University, Ames, IA 50011, USA; Department of Entomology, Iowa State University, Ames, IA 50011, USA.
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Crava CM, Bel Y, Jakubowska AK, Ferré J, Escriche B. Midgut aminopeptidase N isoforms from Ostrinia nubilalis: activity characterization and differential binding to Cry1Ab and Cry1Fa proteins from Bacillus thuringiensis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2013; 43:924-935. [PMID: 23933214 DOI: 10.1016/j.ibmb.2013.07.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 07/23/2013] [Accepted: 07/29/2013] [Indexed: 06/02/2023]
Abstract
Aminopeptidase N (APN) isoforms from Lepidoptera are known for their involvement in the mode of action of insecticidal Cry proteins from Bacillus thuringiensis. These enzymes belong to a protein family with at least eight different members that are expressed simultaneously in the midgut of lepidopteran larvae. Here, we focus on the characterization of the APNs from Ostrinia nubilalis (OnAPNs) to identify potential Cry receptors. We expressed OnAPNs in insect cells using a baculovirus system and analyzed their enzymatic activity by probing substrate specificity and inhibitor susceptibility. The interaction with Cry1Ab and Cry1Fa proteins (both found in transgenic insect-resistant maize) was evaluated by ligand blot assays and immunocytochemistry. Ligand blots of brush border membrane proteins showed that both Cry proteins bound mainly to a 150 kDa-band, in which OnAPNs were greatly represented. Binding analysis of Cry proteins to the cell-expressed OnAPNs showed that OnAPN1 interacted with both Cry1Ab and Cry1Fa, whereas OnAPN3a and OnAPN8 only bound to Cry1Fa. Two isoforms, OnAPN2 and OnAPN3b, did not interact with any of these two proteins. This work provides the first evidence of a differential role of OnAPN isoforms in the mode of action of Cry proteins in O. nubilalis.
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Affiliation(s)
- Cristina M Crava
- Department of Genetics, University of Valencia, Dr. Moliner 50, 46100 Burjassot, Valencia, Spain.
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Insecticidal activity of Bacillus thuringiensis Cry1Bh1 against Ostrinia nubilalis (Hubner) (Lepidoptera: Crambidae) and other lepidopteran pests. Appl Environ Microbiol 2013; 79:7590-7. [PMID: 24077715 DOI: 10.1128/aem.01979-13] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Bacillus thuringiensis is an important source of insect resistance traits in commercial crops. In an effort to prolong B. thuringiensis trait durability, insect resistance management programs often include combinations of insecticidal proteins that are not cross resistant or have demonstrable differences in their site of action as a means to mitigate the development of resistant insect populations. In this report, we describe the activity spectrum of a novel B. thuringiensis Cry protein, Cry1Bh1, against several lepidopteran pests, including laboratory-selected B. thuringiensis-resistant strains of Ostrinia nubilalis and Heliothis virescens and progeny of field-evolved B. thuringiensis-resistant strains of Plutella xylostella and Spodoptera frugiperda. Cry1Bh1 is active against susceptible and B. thuringiensis-resistant colonies of O. nubilalis, P. xylostella, and H. virescens in laboratory diet-based assays, implying a lack of cross-resistance in these insects. However, Cry1Bh1 is not active against susceptible or Cry1F-resistant S. frugiperda. Further, Cry1Bh1 does not compete with Cry1Fa or Cry1Ab for O. nubilalis midgut brush border membrane binding sites. Cry1Bh1-expressing corn, while not completely resistant to insect damage, provided significantly better leaf protection against Cry1Fa-resistant O. nubilalis than did Cry1Fa-expressing hybrid corn. The lack of cross-resistance with Cry1Ab and Cry1Fa along with independent membrane binding sites in O. nubilalis makes Cry1Bh1 a candidate to further optimize for in-plant resistance to this pest.
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Coates BS, Johnson H, Kim KS, Hellmich RL, Abel CA, Mason C, Sappington TW. Frequency of hybridization between Ostrinia nubilalis E-and Z-pheromone races in regions of sympatry within the United States. Ecol Evol 2013; 3:2459-70. [PMID: 24567821 PMCID: PMC3930039 DOI: 10.1002/ece3.639] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 05/07/2013] [Accepted: 05/08/2013] [Indexed: 01/13/2023] Open
Abstract
Female European corn borer, Ostrinia nubilalis, produce and males respond to sex pheromone blends with either E- or Z-Δ11-tetradecenyl acetate as the major component. E- and Z-race populations are sympatric in the Eastern United States, Southeastern Canada, and the Mediterranean region of Europe. The E- and Z-pheromone races of O. nubilalis are models for incipient species formation, but hybridization frequencies within natural populations remain obscure due to lack of a high-throughput phenotyping method. Lassance et al. previously identified a pheromone gland-expressed fatty-acyl reductase gene (pgfar) that controls the ratio of Δ11-tetradecenyl acetate stereoisomers. We identified three single nucleotide polymorphism (SNP) markers within pgfar that are differentially fixed between E- and Z-race females, and that are ≥98.2% correlated with female pheromone ratios measured by gas chromatography. Genotypic data from locations in the United States demonstrated that pgfar-z alleles were fixed within historically allopatric Z-pheromone race populations in the Midwest, and that hybrid frequency ranged from 0.00 to 0.42 within 11 sympatric sites where the two races co-occur in the Eastern United States (mean hybridization frequency or heterozygosity (H O) = 0.226 ± 0.279). Estimates of hybridization between the E- and Z-races are important for understanding the dynamics involved in maintaining race integrity, and are consistent with previous estimates of low levels of genetic divergence between E- and Z-races and the presence of weak prezygotic mating barriers. This work describes the development of new single nucleotide polymorphism (SNP) markers within the pheromone gland expressed fatty acyl reductase (pgfar) gene of Ostrinia nubilalis. These SNPs were shown to segregate based upon female pheromone production, and thus provide the first description of an assay for genetic determination of O. nubilalis pheromone strain from field-collected samples. These assays were applied to estimate hybridization within field populations, and represent valuable tools for future population genetic studies of this species.
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Affiliation(s)
- Brad S Coates
- USDA-ARS, Corn Insects and Crop Genetics Research Unit, Genetics Laboratory, Iowa State University Ames, Iowa, 50011 ; Department of Entomology, Iowa State University Ames, Iowa, 50011
| | - Holly Johnson
- Entomology and Wildlife Ecology, University of Delaware 531 S College Ave RM 250, Newark, Delaware, 19716-2160
| | - Kyung-Seok Kim
- USDA-ARS, Corn Insects and Crop Genetics Research Unit, Genetics Laboratory, Iowa State University Ames, Iowa, 50011
| | - Richard L Hellmich
- USDA-ARS, Corn Insects and Crop Genetics Research Unit, Genetics Laboratory, Iowa State University Ames, Iowa, 50011 ; Department of Entomology, Iowa State University Ames, Iowa, 50011
| | - Craig A Abel
- USDA-ARS, Corn Insects and Crop Genetics Research Unit, Genetics Laboratory, Iowa State University Ames, Iowa, 50011
| | - Charles Mason
- Entomology and Wildlife Ecology, University of Delaware 531 S College Ave RM 250, Newark, Delaware, 19716-2160
| | - Thomas W Sappington
- USDA-ARS, Corn Insects and Crop Genetics Research Unit, Genetics Laboratory, Iowa State University Ames, Iowa, 50011 ; Department of Entomology, Iowa State University Ames, Iowa, 50011
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Hernández-Rodríguez CS, Hernández-Martínez P, Van Rie J, Escriche B, Ferré J. Shared midgut binding sites for Cry1A.105, Cry1Aa, Cry1Ab, Cry1Ac and Cry1Fa proteins from Bacillus thuringiensis in two important corn pests, Ostrinia nubilalis and Spodoptera frugiperda. PLoS One 2013; 8:e68164. [PMID: 23861865 PMCID: PMC3702569 DOI: 10.1371/journal.pone.0068164] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 05/27/2013] [Indexed: 12/29/2022] Open
Abstract
First generation of insect-protected transgenic corn (Bt-corn) was based on the expression of Cry1Ab or Cry1Fa proteins. Currently, the trend is the combination of two or more genes expressing proteins that bind to different targets. In addition to broadening the spectrum of action, this strategy helps to delay the evolution of resistance in exposed insect populations. One of such examples is the combination of Cry1A.105 with Cry1Fa and Cry2Ab to control O. nubilalis and S. frugiperda. Cry1A.105 is a chimeric protein with domains I and II and the C-terminal half of the protein from Cry1Ac, and domain III almost identical to Cry1Fa. The aim of the present study was to determine whether the chimeric Cry1A.105 has shared binding sites either with Cry1A proteins, with Cry1Fa, or with both, in O. nubilalis and in S. frugiperda. Brush-border membrane vesicles (BBMV) from last instar larval midguts were used in competition binding assays with (125)I-labeled Cry1A.105, Cry1Ab, and Cry1Fa, and unlabeled Cry1A.105, Cry1Aa, Cry1Ab, Cry1Ac, Cry1Fa, Cry2Ab and Cry2Ae. The results showed that Cry1A.105, Cry1Ab, Cry1Ac and Cry1Fa competed with high affinity for the same binding sites in both insect species. However, Cry2Ab and Cry2Ae did not compete for the binding sites of Cry1 proteins. Therefore, according to our results, the development of cross-resistance among Cry1Ab/Ac, Cry1A.105, and Cry1Fa proteins is possible in these two insect species if the alteration of shared binding sites occurs. Conversely, cross-resistance between these proteins and Cry2A proteins is very unlikely in such case.
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Affiliation(s)
| | | | | | | | - Juan Ferré
- Departamento de Genética, Universitat de València, Burjassot, Spain
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Transgenic approaches to western corn rootworm control. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2013; 136:135-62. [PMID: 23604211 DOI: 10.1007/10_2013_195] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) is a significant corn pest throughout the United States corn belt. Rootworm larvae feed on corn roots causing yield losses and control expenditures that are estimated to exceed US$1 billion annually. Traditional management practices to control rootworms such as chemical insecticides or crop rotation have suffered reduced effectiveness due to the development of physiological and behavioral resistance. Transgenic maize expressing insecticidal proteins are very successful in protecting against rootworm damage and preserving corn yield potential. However, the high rate of grower adoption and early reliance on hybrids expressing a single mode of action and low-dose traits threatens the durability of commercialized transgenic rootworm technology for rootworm control. A summary of current transgenic approaches for rootworm control and the corresponding insect resistance management practices is included. An overview of potential new modes of action based on insecticidal proteins, and especially RNAi targeting mRNA coding for essential insect proteins is provided.
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Scientific Opinion updating the risk assessment conclusions and risk management recommendations on the genetically modified insect resistant maize 1507. EFSA J 2012. [DOI: 10.2903/j.efsa.2012.2933] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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