Divergent receptor proteins confer responses to different karrikins in two ephemeral weeds
Bibliographic record
Abstract
ABSTRACT Wildfires can encourage the establishment of invasive plants by releasing potent germination stimulants, such as karrikins. Seed germination of Brassica tournefortii , a noxious weed of Mediterranean climates, is strongly stimulated by KAR 1 , which is the archetypal karrikin produced from burning vegetation. In contrast, the closely-related yet non-fire-associated ephemeral Arabidopsis thaliana is unusual because it responds preferentially to KAR 2 . The α/β-hydrolase KARRIKIN INSENSITIVE2 (KAI2) is the putative karrikin receptor identified in Arabidopsis . Here we show that B. tournefortii differentially expresses three KAI2 homologues, and the most highly-expressed homologue is sufficient to confer enhanced responses to KAR 1 relative to KAR 2 when expressed in Arabidopsis . We further identify two variant amino acid residues near the KAI2 active site that explain the ligand selectivity, and show that this combination has arisen independently multiple times within dicots. Our results suggest that duplication and diversification of KAI2 proteins could confer upon weedy ephemerals and potentially other angiosperms differential responses to chemical cues produced by environmental disturbance, including fire.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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 teacher head, 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".