Characterization and Transcriptome Analysis Reveal Abnormal Pollen Germination in Cytoplasmic Male Sterile Tomato
Bibliographic record
Abstract
Cytoplasmic male sterility (CMS) is a plant trait wherein plants cannot develop normal male organs because of the mitochondrial genes. Although the mitochondrial gene orf137 has been identified as the CMS-causing gene in tomatoes, its function remains unclear. In this study, we characterized the sterile male phenotypes and analyzed the CMS pollen transcriptome. Microscopic and calcium imaging analyses revealed that CMS pollen exhibited abnormal germination from multiple apertures, accompanied by elevated calcium concentrations and vesicle accumulation, which are typically observed in pollen tube tips. RNA-Seq analysis revealed 440 differentially expressed genes, including four pectin methylesterase inhibitor (PMEI) genes that were highly expressed in the pollen. PME activity was significantly reduced in CMS pollen, suggesting its association with abnormal pollen germination. ATP and reactive oxygen species (ROS) levels, which are key mediators of mitochondrial retrograde signaling (MRS), remained unchanged in CMS pollen, and the expression of the mitochondrial stress marker AOX1a was not elevated. These findings suggest that orf137 triggers an alternative MRS pathway independent of ATP or ROS, potentially leading to PMEI upregulation and abnormal pollen germination. Our results reveal a previously unrecognized mechanism of CMS-induced male sterility in tomatoes involving nuclear gene regulation through unconventional mitochondrial signaling.
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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".