Ethylene is integrated into the nitric oxide regulation of Arabidopsis somatic embryogenesis
Bibliographic record
Abstract
The study confirms the role of the two Arabidopsis hemoglobin genes (Glb1 and Glb2) during somatic embryogenesis and proposes the involvement of ethylene in the regulation of embryo development. Suppression of both Glb1 and Glb2 results in accumulation of nitric oxide (NO) and a different embryogenic response. Compared to WT tissue, down-regulation of Glb1 (Glb1 RNAi line) compromises the embryogenic process, while repression of Glb2 (Glb2−/− line) increases the number of embryos. These differences were ascribed to the differential accumulation of NO in the two lines, as Glb1 is a more effective NO scavenger compared to Glb2. A high elevation of NO level [achieved pharmacologically using the NO donor sodium nitroprusside (SNP), or genetically using the Glb1 suppressing line], activated the two ethylene biosynthetic genes 1-aminocyclopropane-1-carboxylate synthase (ACC synthase) and 1-aminocyclopropane-1-carboxylate oxidase (ACC oxidase). Ethylene accumulation repressed embryogenesis, as shown by the decreased embryo number observed in tissue treated with the ethylene releasing agent Ethephon (ETH), as well as by the increased embryo production obtained with the two ethylene insensitive mutant lines (ein2-1 and ein3-1). A repression in ethylene level increased the expression of many auxin biosynthetic genes and favored the accumulation of the auxin indole-acetic acid (IAA) at the sites of the explants where embryogenic tissue will form. Collectively these data reveal that high levels of NO, generated by the Glb1 suppressing line, but not by the Glb2 suppressing line, might increase the level of ethylene, which represses the production of auxin. Auxin is the inductive signal required for the formation of the embryogenic tissue.
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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 | 0.000 |
| 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".