scholarly journals Genetic Screening to Identify Candidate Resistance Alleles to Cry1F Corn in Fall Armyworm Using Targeted Sequencing

Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 618
Author(s):  
Katrina Schlum ◽  
Kurt Lamour ◽  
Peter Tandy ◽  
Scott J. Emrich ◽  
Caroline Placidi de Bortoli ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Receptor Gene ◽  
Fall Armyworm ◽  
Field Resistance ◽  
Targeted Sequencing ◽  
Screening Methods ◽  
Resistance Allele ◽  
Bt Crops ◽  
Development Of Resistance ◽  
Monitoring Tools

Evolution of practical resistance is the main threat to the sustainability of transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt crops). Monitoring of resistance to Cry and Vip3A proteins produced by Bt crops is critical to mitigate the development of resistance. Currently, Cry/Vip3A resistance allele monitoring is based on bioassays with larvae from inbreeding field-collected moths. As an alternative, DNA-based monitoring tools should increase sensitivity and reduce overall costs compared to bioassay-based screening methods. Here, we evaluated targeted sequencing as a method allowing detection of known and novel candidate resistance alleles to Cry proteins. As a model, we sequenced a Cry1F receptor gene (SfABCC2) in fall armyworm (Spodoptera frugiperda) moths from Puerto Rico, a location reporting continued practical field resistance to Cry1F-producing corn. Targeted sequencing detected a previously reported Cry1F resistance allele (SfABCC2mut), in addition to a resistance allele originally described in S. frugiperda populations from Brazil. Moreover, targeted sequencing detected mutations in SfABCC2 as novel candidate resistance alleles. These results support further development of targeted sequencing for monitoring resistance to Bt crops and provide unexpected evidence for common resistance alleles in S. frugiperda from Brazil and Puerto Rico.

scholarly journals Effectiveness of Push–Pull Systems to Fall Armyworm (Spodoptera frugiperda) Management in Maize Crops in Morelos, Mexico

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 298
Author(s):  
Ouorou Ganni Mariel Guera ◽  
Federico Castrejón-Ayala ◽  
Norma Robledo ◽  
Alfredo Jiménez-Pérez ◽  
Georgina Sánchez-Rivera ◽  
...  
Keyword(s):  
Spodoptera Frugiperda ◽  
Insect Pest ◽  
Fall Armyworm ◽  
Maize Yield ◽  
Morphological Development ◽  
Main Method ◽  
Development Of Resistance ◽  
Pull Systems ◽  
Complex Scenario ◽  
Block Experiment

Chemical control is the main method used to combat fall armyworm in maize crops. However, its indiscriminate use usually leads to a more complex scenario characterized by loss of its effectiveness due to the development of resistance of the insect pest, emergence of secondary pests, and reduction of the populations of natural enemies. For this reason, efforts to develop strategies for agroecological pest management such as Push–Pull are increasingly growing. In this context, the present study was carried out to evaluate field effectiveness of Push–Pull systems for S. frugiperda management in maize crops in Morelos, Mexico. In a randomized block experiment, the incidence and severity of S. frugiperda, the development and yield of maize were evaluated in nine Push–Pull systems and a maize monoculture. The Push–Pull systems presented incidence/severity values lower than those of the monoculture. Morphological development and maize yield in the latter were lower than those of most Push–Pull systems. Mombasa—D. ambrosioides, Mulato II—T. erecta, Mulato II—C. juncea, Tanzania—T. erecta and Tanzania—D. ambrosioides systems presented higher yields than those of monocultures.

Field-Evolved Resistance of the Fall Armyworm (Lepidoptera: Noctuidae) to Synthetic Insecticides in Puerto Rico and Mexico

2018 ◽  
Vol 112 (2) ◽  
pp. 792-802 ◽  
Author(s):  
Rebeca Gutiérrez-Moreno ◽  
David Mota-Sanchez ◽  
Carlos A Blanco ◽  
Mark E Whalon ◽  
Henry Terán-Santofimio ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Fall Armyworm ◽  
Lepidoptera Noctuidae

Field Resistance of Bacillus thuringiensis Berliner Transformed Maize to Fall Armyworm (Lepidoptera: Noctuidae) and Southwestern Corn Borer (Lepidoptera: Crambidae) Leaf Feeding

2004 ◽  
Vol 39 (3) ◽  
pp. 325-336 ◽  
Author(s):  
Craig A. Abel ◽  
Melanie C. Pollan
Keyword(s):  
Bacillus Thuringiensis ◽  
Fall Armyworm ◽  
Field Resistance ◽  
Economic Damage ◽  
Yield Reduction ◽  
Insecticidal Proteins ◽  
Corn Borer ◽  
Field Efficacy ◽  
Southwestern Corn Borer ◽  
Hybrid Maize

The fall armyworm, Spodoptera frugiperda (J. E. Smith), and the southwestern corn borer, Diatraea grandiosella (Dyar), can cause economic damage to maize, Zea mays L., grown in the southeastern United States. Maize hybrids are commercially available that have been transformed to express insecticidal crystalline proteins from Bacillus thuringiensis (Bt) Berliner. The field efficacy of seven Bt hybrids were tested for control of leaf-feeding fall armyworm and southwestern corn borer. All Bt hybrids performed better than their conventional near-isolines for control of both insects. In general, the Bt hybrids provided intermediate resistance to the fall armyworm and near immunity to the southwestern corn borer. Based on larval establishment and weights, the fall armyworm was more tolerant of the insecticidal proteins expressed by the Bt hybrids than the southwestern corn borer. There was no difference in expression of insecticidal proteins among the Bt hybrids. Bt hybrids should be advantageous for the production of maize in areas that are affected by southwestern corn borer. The moderate level of resistance in the Bt hybrids to fall armyworm should be further examined to determine if amplifying the expression of insecticidal proteins or integrating other control methods along with the use of current Bt hybrid maize is needed to protect the crop from yield reduction by this pest.

scholarly journals Identification of Resistance to Multiple Fungicides in Field Populations of Venturia inaequalis

Plant Disease ◽  
2011 ◽  
Vol 95 (8) ◽  
pp. 921-926 ◽  
Author(s):  
Kimberly S. Chapman ◽  
George W. Sundin ◽  
Janna L. Beckerman
Keyword(s):  
Fungicide Resistance ◽  
Mycelial Growth ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Field Resistance ◽  
Single Spore ◽  
Mycelium Growth ◽  
Thiophanate Methyl ◽  
Development Of Resistance

Venturia inaequalis, the causal agent of apple scab, is controlled primarily by fungicides. Long-term, extensive fungicide use has led to the development of resistance to multiple fungicides. To assess fungicide resistance, isolates of V. inaequalis were collected from Indiana and Michigan orchards. Single-spore derived isolates were evaluated by mycelium growth assays with previously determined discriminatory doses on media containing dodine, kresoxim-methyl, myclobutanil, or thiophanate-methyl. Of 195 isolates tested, 5.2, 0.7, 57.0, and 92.6% of isolates were found to be resistant to dodine, kresoxim-methyl, myclobutanil, and thiophanate-methyl, respectively. This is the first report of kresoxim-methyl field resistance in these states. Isolates resistant or shifted to a single fungicide were often found to have multiple fungicide resistance. Of all isolates tested, 38% were identified as resistant or shifted to two fungicides, and 12% were resistant or shifted to all four fungicides tested. No fitness penalty was found for isolates resistant to multiple fungicides based on a statistical analysis of mycelial growth and conidial production.

scholarly journals Whole genome comparisons reveal panmixia among fall armyworm (Spodoptera frugiperda) from diverse locations

2020 ◽  
Author(s):  
Katrina A. Schlum ◽  
Kurt Lamour ◽  
Caroline Placidi de Bortoli ◽  
Rahul Banerjee ◽  
Scott J. Emrich ◽  
...  
Keyword(s):  
United States ◽  
Puerto Rico ◽  
Gene Flow ◽  
Spodoptera Frugiperda ◽  
Fall Armyworm ◽  
The United States ◽  
Genomic Diversity ◽  
Whole Genome ◽  
Long Distance ◽  
Host Strains

AbstractThe fall armyworm (Spodoptera frugiperda (J.E. Smith)) is a highly polyphagous agricultural pest with long-distance migratory behavior threatening food security worldwide. This pest has a host range of >80 plant species, but two host strains are recognized based on their association with corn (C-strain) or rice and smaller grasses (R-strain). In this study, the population structure and genetic diversity in 55 S. frugiperda samples from Argentina, Brazil, Kenya, Puerto Rico and the United States (USA) were surveyed to further our understanding of whole genome nuclear diversity. Comparisons at the genomic level suggest panmixia in this population, other than a minor reduction in gene flow between the two overwintering populations in the continental USA that also corresponded to genetically distinct host strains. Two maternal lines were detected from analysis of mitochondrial genomes. We found members from the Eastern Hemisphere interspersed within both continental USA overwintering subpopulations, suggesting multiple individuals were likely introduced to Africa. Comparisons between laboratory-reared and field collected S. frugiperda support similar genomic diversity, validating the experimental use of laboratory strains. Our research is the largest diverse collection of United States S. frugiperda whole genome sequences characterized to date, covering eight continental states and a USA territory (Puerto Rico). The genomic resources presented provide foundational information to understand gene flow at the whole genome level among S. frugiperda populations.

scholarly journals Whole genome comparisons reveal panmixia among fall armyworm (Spodoptera frugiperda) from diverse locations

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Katrina A. Schlum ◽  
Kurt Lamour ◽  
Caroline Placidi de Bortoli ◽  
Rahul Banerjee ◽  
Robert Meagher ◽  
...  
Keyword(s):  
United States ◽  
Puerto Rico ◽  
Gene Flow ◽  
Spodoptera Frugiperda ◽  
Fall Armyworm ◽  
The United States ◽  
Whole Genome ◽  
Long Distance ◽  
Field Samples ◽  
Host Strains

Abstract Background The fall armyworm (Spodoptera frugiperda (J.E. Smith)) is a highly polyphagous agricultural pest with long-distance migratory behavior threatening food security worldwide. This pest has a host range of > 80 plant species, but two host strains are recognized based on their association with corn (C-strain) or rice and smaller grasses (R-strain). The population genomics of the United States (USA) fall armyworm remains poorly characterized to date despite its agricultural threat. Results In this study, the population structure and genetic diversity in 55 S. frugiperda samples from Argentina, Brazil, Kenya, Puerto Rico and USA were surveyed to further our understanding of whole genome nuclear diversity. Comparisons at the genomic level suggest a panmictic S. frugiperda population, with only a minor reduction in gene flow between the two overwintering populations in the continental USA, also corresponding to distinct host strains at the mitochondrial level. Two maternal lines were detected from analysis of mitochondrial genomes. We found members from the Eastern Hemisphere interspersed within both continental USA overwintering subpopulations, suggesting multiple individuals were likely introduced to Africa. Conclusions Our research is the largest diverse collection of United States S. frugiperda whole genome sequences characterized to date, covering eight continental states and a USA territory (Puerto Rico). The genomic resources presented provide foundational information to understand gene flow at the whole genome level among S. frugiperda populations. Based on the genomic similarities found between host strains and laboratory vs. field samples, our findings validate the experimental use of laboratory strains and the host strain differentiation based on mitochondria and sex-linked genetic markers extends to minor genome wide differences with some exceptions showing mixture between host strains is likely occurring in field populations.

scholarly journals Resistance to Infection by Subgroups B, D, and E Avian Sarcoma and Leukosis Viruses Is Explained by a Premature Stop Codon within a Resistance Allele of the tvb Receptor Gene

2002 ◽  
Vol 76 (15) ◽  
pp. 7918-7921 ◽  
Author(s):  
Sara Klucking ◽  
Heather B. Adkins ◽  
John A. T. Young
Keyword(s):  
Stop Codon ◽  
Receptor Gene ◽  
Premature Stop Codon ◽  
Resistance Allele ◽  
Truncated Protein ◽  
Single Base ◽  
Single Base Pair ◽  
Resistance To Infection ◽  
Avian Sarcoma

ABSTRACT Here we present the first molecular characterization of the defect associated with an avian sarcoma and leukosis virus (ASLV) receptor resistance allele, tvb r. We show that resistance to infection by subgroups B, D, and E ASLV is explained by the presence of a single base pair mutation that distinguishes this allele from tvb s1, an allele which encodes a receptor for all three viral subgroups. This mutation generates an in-frame stop codon that is predicted to lead to the production of a severely truncated protein.

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