Role of Exopolysaccharide in Pantoea agglomerans Interactions with Bacteriophages
Bibliographic record
Abstract
Fire blight is the common name given to a disease caused by phytopathogen, Erwinia amylovora. This pathogen infects plants belonging to the rosaceous family, particularly the commercially grown apple and pear cultivars in North America. Agriculture and Agri-Food Canada Research team has focused on the use of bacteriophages as biological control agents for the control of fire blight. Bacteriophage persistence in the orchard environment can be affected by various environmental factors such as exposure to ultraviolet light and dry conditions. In order to improve phage viability during application, a carrier-phage system was developed that uses a non-pathogenic epiphytic bacterium, named “the carrier”, that protects the bacteriophages during processing and field applications. The bacterium used is Pantoea agglomerans, which delivers and propagates the phages to the open blossoms, prior to the arrival of E. amylovora. In addition, the carrier alone may act as a biological control agent on the blossom surface, competing for space and producing antibiotics targeting E. amylovora. The aim of this study was study the interaction between the phage and the carrier bacterium, P. agglomerans. The exopolysaccharide (EPS) layer, is the first cellular component which bacteriophages encounter during the infection of P. agglomerans. PCR was conducted and it confirmed that 6 genes involved in EPS biosynthesis were present within the four different isolates of P. agglomerans. A CRISPR/Cas9 knockout and lambda red recombineering protocol was used to construct EPS deficient P. agglomerans mutants. The deficient populations were confirmed using colony appearance, PCR and Sangar sequencing. A quantitative PCR was conducted to quantify and compare the different bacteriophage populations between the wild-type and deficient EPS mutants. The EPS mutants were found to have shown a significantly decreased or complete lack of growth in both Myoviridae and Podoviridae infections.
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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 | 0.001 |
| Research integrity | 0.001 | 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".