Frequency of alleles linked to Cry1F resistance in European corn borer (Lepidoptera: Crambidae) from the United States
Bibliographic record
Abstract
Corn genetically engineered to produce insecticidal proteins from Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) (ie Bt corn) has toxicity against specific insect pests. However, field-evolved resistance to Bt crops has emerged in several species, including the European corn borer (ECB, Ostrinia nubilalis Hübner). The first case of practical resistance in ECB to Bt corn producing the Cry1F insecticidal protein was documented in 2018 in Nova Scotia, Canada. Six mutations in an ABC transporter gene (OnABCC2) were associated with this resistance; five of these caused nonsynonymous amino acid changes and one causes a two base pair deletion (TA12076-) resulting in a frameshift and premature stop codon. We genotyped 364 ECB individuals collected between 2022 and 2023 across the USA at these six loci and complemented the analysis with targeted OnABCC2 exome sequencing and ECB strain association analysis. Allele frequencies significantly varied across markers and locations. The TA12076- allele was detected in 2023 at a low frequency (0.01) across all sites. Targeted OnABCC2 exome sequencing identified 130 alleles, 41 of them which cause nonsynonymous changes, but no additional indels. Strain genotyping matched previously known ECB strain distributions but showed no association with Bt resistance Our data indicated that the TA12076- allele occurred at low frequency in U.S. populations, consistent with the absence of reported Cry1F field failures, as resistance is recessive. This indel was detected in heterozygous individuals from 3 populations (New Hampshire, Ohio, and Iowa). These observations underscore the importance of efforts monitoring for Bt resistance evolution and spread in ECB populations.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".