The rice microRNA159<i>–SPOROCYTELESS EAR2</i> module regulates starch biosynthesis during pollen development and maintains male fertility
Bibliographic record
Abstract
Starch is an indispensable energy reserve for pollen and failure of starch biosynthesis in pollen leads to male sterility in flowering crops. Nonetheless, the regulatory mechanisms underlying starch biosynthesis in rice (Oryza sativa) pollen remain unclear. Here, we identified a target of the microRNA OsmiR159, SPOROCYTELESS ETHYLENE-RESPONSIVE ELEMENT BINDING FACTOR-ASSOCIATED AMPHIPHILIC-REPRESSION 2 (OsSPEAR2). OsSPEAR2 is predominantly expressed in mature pollen and OsSPEAR2 possesses transcriptional repressor activity and localizes in the nucleus. Disruption of OsSPEAR2 results in severely shrunken pollen grains and male sterility. OsSPEAR2 interacts with multiple OsTCPs, including OsTCP14. OsTCP14 is a target of OsmiR319 and a knockout mutation in OsTCP14 partially rescues the defective pollen phenotype of Osspear2. In addition, transcriptome analyses revealed significant downregulation of numerous genes associated with carbohydrate metabolism, specifically in Osspear2 anthers, including several genes critical for starch biosynthesis. Moreover, OsTCP14 directly represses the expression of the essential starch biosynthesis gene OsUGP2; however, this repression could be alleviated by OsSPEAR2. Noteworthily, embryophyte-specific SPEAR2 and SPOROCYTELESS were also identified as miR159 targets involved in regulating plant growth and development in Arabidopsis (Arabidopsis thaliana), indicating that the miR159-SPEAR regulatory module may be conserved among embryophytes. Collectively, our findings reveal OsmiR159-OsSPEAR2-OsTCP14-OsUGP2 as a regulatory cascade that modulates starch biosynthesis during pollen development in rice.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 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 | 0.001 | 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) | 0.000 | 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 teacher head, 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".