Ectopic expression of C-terminal tubulin variants alters wood composition and structure in Populus
Bibliographic record
Abstract
Cortical microtubules are cytoskeletal components that are relevant to the bioenergy and forest products industry due to their postulated role in orchestrating cellulose microfibril deposition during cell wall formation.The microtubule component proteins α-(TUA) and β-tubulins (TUB) are encoded by multi-gene families with very high overall sequence homology across species.To advance our initial characterization studies (Oakley et al., 2007), we have developed a suite of transgenic Populus that exhibit perturbed TUA to TUB transcript ratios, or that express tubulin PTM mimics.Most of the construct combinations resulted in abnormal organogenesis and vascular development, and failed to produce viable plants.Only three of the combinations led to wholeplant regeneration, and interestingly, all three featured the C-terminal variants.This is significant because the C-terminus is the post-translational modification (PTM) hot-spot in animal tubulins.One of the PTM mimics that we developed lacks a C-terminal tyrosine, thought to be the target of a tyrosine cleavage and re-ligation cycle important for tubulin regulation in animal cells.The transgenic trees appeared morphologically normal, but exhibited a range of epinasty and twisting phenotypes in mature leaves.Bark color was noticeably lighter in the transgenics.Microfibril angle, wood density, lignin content, lignin structure and metabolic profiles were altered in the transgenic wood.The results are consistent with a function of microtubules and microtubule PTMs for plant development and cell wall biogenesis in Populus, and offer novel strategies to manipulation of wood properties.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".