Polyphenol Oxidase from Hybrid Poplar. Cloning and Expression in Response to Wounding and Herbivory
Bibliographic record
Abstract
The inducible expression of polyphenol oxidase (PPO), a presumed antiherbivore enzyme, was examined in hybrid poplar (Populus trichocarpa x Populus deltoides). Following mechanical wounding simulating insect damage, PPO activity increased dramatically in wounded and unwounded leaves on wounded plants beginning at 24 and 48 h, respectively. A hybrid poplar PPO cDNA was isolated and its nucleotide sequence determined. On northern blots, PPO transcripts were detected within 8 h of wounding, and reached peak levels at 16 and 24 h in wounded and unwounded leaves, respectively. Methyl jasmonate spray and feeding by forest tent caterpillar also induced PPO expression. The induction of PPO was strongest in the youngest four leaves, which were generally avoided by caterpillars in free feeding experiments. This wound- and herbivore-induced expression of PPO in hybrid poplar supports the defensive role of this protein against insect pests.
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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 | 0.001 |
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".