ABA-regulated JAZ1 Proteins Bind NAC42 Transcription Factors to Suppress the Activation of Phytoalexin Biosynthesis in Plants
Bibliographic record
Abstract
SUMMARY Phytoalexins are plant defense metabolites whose biosynthesis remains suppressed until elicited by a pathogen or stress, yet the mechanism of their suppression has remained elusive. The transcription factor GmNAC42-1 is an important and direct activator of the biosynthesis of glyceollin phytoalexins in soybean. Yet, without elicitation, overexpressing GmNAC42-1 is insufficient to activate the expression of glyceollin biosynthetic genes, suggesting that the activity of GmNAC42-1 may be suppressed by a negative regulator. JAZ1 proteins are negative regulators of the canonical jasmonic acid (JA) signaling pathway. JAZ protein degradation and JAZ gene transcription comprise antagonistic mechanisms that activate and suppress JA signaling, respectively. In search for negative regulators of glyceollin biosynthesis, we identified by RNA-seq analysis abscisic acid (ABA) signaling and GmJAZ1 genes that are oppositely regulated compared to glyceollin biosynthesis. Long-term ABA treatment upregulated GmJAZ1 transcripts, whereas its biosynthesis inhibitor fully suppressed their upregulation by dehydration stress. Opposite patterns were observed for glyceollin biosynthesis. RNAi silencing of GmJAZ1s prevented the suppression of glyceollin biosynthesis by dehydration and derepressed glyceollin synthesis in non-elicited tissues. Overexpressing GmJAZ1-9 in hairy roots elicited with Phytophthora sojae wall glucan elicitor partially suppressed glyceollin biosynthesis. The GmJAZ1-9 protein physically interacted with GmNAC42-1 and inhibited its transactivation and DNA binding activities in promoter-luciferase and yeast-three hybrid systems. Silencing JAZ1s in Arabidopsis and grapevine has been reported to derepress camalexin and stilbene phytoalexin biosynthesis. Here, we found that JAZ1 and NAC42 proteins from all three plant species physically interact, suggesting a conserved mechanism negatively regulates phytoalexin biosynthesis in plants. Abstract Figure
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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 | 0.001 |
| 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".