Azomycin produced by <i>Pseudomonas</i> has both phytotoxic and anti-oomycete activity
Bibliographic record
Abstract
ABSTRACT Members of the genus Pseudomonas synthesize diverse natural products that contribute to their versatility in free-living and host-associated lifestyles. Here, we characterized the in vivo functions of the nitroimidazole antibiotic azomycin in the genus Pseudomonas . We found that genes with similarity to azomycin biosynthesis genes rohPQRST are prevalent within the Pseudomonas syringae species complex and rarely present in the Pseudomonas fluorescens species complex. Azomycin production was detectable in culture by biocontrol strains Pseudomonas spp. DF41 and CMR5a. Pseudomonas sp. DF41 exhibited anti-oomycete activity that was lost in a ∆rohPQRST mutant. Purified azomycin was sufficient to kill the oomycete pathogens Aphanomyces and Phytophthora . Although DF41 has been studied for its role in biocontrol of plant pathogens, we found that azomycin exhibited phytotoxicity against Pisum sativum (pea) plants at similar concentrations to those that inhibited oomycetes. However, consistent with its use as a biocontrol agent, Pseudomonas sp. DF41 only produced azomycin in planta when pea plants were infected with the oomycete pathogen Aphanomyces euteiches . Our findings suggest dual roles for azomycin in Pseudomonas, functioning both as a biocontrol agent of oomycete pathogens, as well as a phytotoxic molecule with a potential role in plant virulence. IMPORTANCE While many natural products are studied for their roles in the treatment of plant or human disease, the ecological functions of natural products are understudied. We found that an antibiotic, azomycin, is produced by Pseudomonas species and has toxicity against both plants and oomycete pathogens. Our findings suggest a complex ecological role of azomycin production by Pseudomonas in both the amelioration and exacerbation of plant disease.
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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".