Stability of the Expression of Acyl‐ACP Thioesterase Transgenes in Oilseed Rape Doubled Haploid Lines
Bibliographic record
Abstract
Transgene stability in doubled haploid (DH) lines is an important consideration for transgenic cultivar development programs. The objective of this study was to assess the expression stability of acyl‐acyl carrier protein (ACP) thioesterase (TE) transgenes in oilseed rape (Brassica napus L.) DH lines. The DH lines were developed from microspores of F1 plants from the crosses between transgenic parents carrying the bay‐TE (Uc FatB1), elm‐TE (Ua FatB1), nutmeg‐TE (Mf FatB1), or cuphea‐TE (Ch FatB1) transgenes and three nontransgenic cultivars having distinct seed oil fatty acid compositions. Of 333 DH1 plants developed from microspore‐derived embryos that had undergone selection for kanamycin resistance (the selectable marker) with bay‐TE F1 and cuphea‐TE F1 plants as the microspore donors, 20 plants did not show TE transgene expression. Polymerase chain reaction (PCR) and Southern blotting analyses confirmed that the absence of TE transgene expression in these 20 DH1 plants was due to escape of embryos from kanamycin selection or existence of an incomplete T‐DNA copy without the TE transgene. No DH1 plant with completely silenced TE transgenes was detected. Thirty of 34 transgenic DH lines showed a stable level of the target fatty acid, lauric acid (C12:0) for the bay‐TE and palmitic acid (C16:0) for the other three TE transgenes, over the two or three consecutive generations tested (DH2, DH3, and/or DH4 plants). Target fatty acids were significantly affected by temperature during seed development. DH lines carrying the elm‐TE or the cuphea‐TE transgene grown under high temperature conditions (25/20°C, day/night) during seed development showed higher levels of palmitic acid than under lower temperatures (20/15°C). These results support the application of the DH procedure in breeding programs for transgenic cultivars and indicate the important influence of environment.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".