Patterns of Arabidopsis gene expression in the face of hypobaric stress
Bibliographic record
Abstract
Extreme hypobaria is a novel abiotic stress that is outside the evolutionary experience of terrestrial plants. In natural environments, the practical limit of atmospheric pressure experienced by higher plants is about 50 kPa or about 0.5 atmospheres; a limit that is primarily imposed by the combined stresses inherent to high altitude conditions of terrestrial mountains. However, in highly controlled chambers, and within projected extra-terrestrial greenhouses, the atmospheric pressure component can be isolated from the associated high altitude stresses such as temperature, desiccation and even hypoxia. Such chambers allow the exploration of hypobaria as a single variable that can be carried to extremes beyond what is possible in terrestrial biomes. Here, we examine the organ-specific progression of transcriptional strategies for the physiological adaptation to various degrees of hypobaric stress, as well as the response to severe hypobaria over time. An abrupt transition from a near-sea level pressure of 97 kPa to a mere 5 kPa is accompanied by the differential expression of hundreds of genes, primarily those associated with drought, hypoxia and cell wall metabolism. However, pressure transitions between these two extremes reveals that plants respond with complex, organ-specific transcriptomic responses, which also vary over time. These responses are not linear; neither with respect to the gradient of hypobaric severity from 75, 50, 25 to 10 kPa, nor with the duration of exposure of up to 3 days at 10 kPa. In the first few hours of hypobaria, plants engage changes in basic metabolism and hormonally mediated growth and development. After 12 or more hours of hypobaria, the gene expression patterns are more indicative of hypoxia and drought environmental responses. The hypobaria transcription patterns were highly organ specific, and roots appeared to be more sensitive to hypobaria than shoots in that the number of differentially expressed genes was higher in roots than in shoots. The patterns of gene expression among organs, across a gradient of atmospheric pressures and over time suggest that plants adapt to the novel stress of pure hypobaria by using recognizable metabolisms to meet appropriately interpreted hypoxia stresses, while engaging drought responses that are seemingly inappropriate to the wet and humid environment of the chambers.
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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".