Callose Deficiency Modulates Plasmodesmata frequency and the intercellular space In Rice Anthers
Bibliographic record
Abstract
Abstract Fertilization relies on pollen mother cells able to transit from mitosis-to-meiosis to supply gametes. This process involves remarkable changes at the molecular, cellular and physiological levels including (but not limited to) remodelling of cell wall. During meiosis onset, cellulose content at the pollen mother cell walls gradually declines with the concurrent deposition of the polysaccharide callose in anther locules. We aim to understand the biological significance of cellulose-to-callose turnover in pollen mother cells walls using electron microscopic analyses of rice flowers. Our observations indicate that in wild type anthers, the mitosis-to-meiosis transition coincides with a gradual reduction in the number of cytoplasmic connections called plasmodesmata. A mutant in the Oryza sativa callose synthase GSL5, impaired in callose accumulation in premeiotic and meiotic anthers, displayed a reduction in plasmodesmata frequency among pollen mother cells and tapetal cells suggesting a role for callose in plasmodesmata maintenance. In addition, a significant increase in cell-cell distance between pollen mother cells and impaired premeiotic cell shaping was observed in the mutant. The results suggest that cellulose-to-callose turnover during mitosis-meiosis transition is necessary to maintain cell-to-cell connections and optimal intercellular spacing among anther locular cells explaining the regulatory influence of callose metabolism during meiosis in flowering plants. Highlights Cellulose-to-callose switch during meiosis onset in pollen mother cell walls correlates with changes in cytoplasmic connections called plasmodesmata, among meiocytes and between meiocytes and surrounding somatic cells. A mutant in GSL5 (glucan synthase like 5) affects callose deposition but no other cell wall component (e.g., cellulose) in premeiotic and meiotic anthers, except at dyad stage. Impaired callose synthesis is proposed to alter plasmodesmata frequency, the extracellular spacing and the shaping of pollen mother cells during mitosis-to-meiosis transition. Increase in plasmodesmata frequency negatively correlates with cell-cell distance between pollen mother cells in both wildtype and a callose mutant.
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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".