Positive and Negative Regulation of the Virulence-Associated Coronafacoyl Phytotoxin in the Potato Common Scab Pathogen <i>Streptomyces scabies</i>
Bibliographic record
Abstract
The potato common scab pathogen Streptomyces scabies produces N-coronafacoyl-l-isoleucine (CFA-Ile), which is a member of the coronafacoyl family of phytotoxins that are synthesized by multiple plant pathogenic bacteria. The CFA-Ile biosynthetic gene cluster contains a regulatory gene, cfaR, which directly controls the expression of the phytotoxin structural genes. In addition, a gene designated orf1 encodes a predicted ThiF family protein and is cotranscribed with cfaR, suggesting that it also plays a role in the regulation of CFA-Ile production. In this study, we demonstrated that CfaR is an essential activator of coronafacoyl phytotoxin production, while ORF1 is dispensable for phytotoxin production and may function as a helper protein for CfaR. We also showed that CFA-Ile inhibits the ability of CfaR to bind to the promoter region driving expression of the phytotoxin biosynthetic genes and that elevated CFA-Ile production by overexpression of both cfaR and orf1 in S. scabies increases the severity of disease symptoms induced by the pathogen during colonization of potato tuber tissue. Overall, our study reveals novel insights into the regulatory mechanisms controlling CFA-Ile production in S. scabies and it provides further evidence that CFA-Ile is an important virulence factor for this organism.
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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 | 0.000 | 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) | 0.000 | 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".