Some phages have evolved to recognize specific polysaccharides of other bacterial species 34 , 54 , So far Erwinia spp. Characterization of a viral EPS-depolymerase, a potential tool for control of fire blight. This led researchers to suggest that Erwinia spp. False-positives were monitored for sample cross-contamination during preparation of mastermix.

Therefore, it seems that two-time injection does not significantly improve shoot blight control by ASM. Phages produced large plaques with expanding translucent halos [e. Simultaneously, the same reactions were run but with the addition of a non-target DNA sample. This limited the inclusion of Myo- and Siphoviridae phages in the study. Studies have shown there are a number of mechanisms by which a bacterium can become resistant to phage infection Labrie et al. Despite numerous attempts, including several alterations to the mutagenesis procedures, double deletion mutants of the HEP isolates were not obtained, suggesting that this genotype is lethal in these bacteria.

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Billing 2 observed in that some phages produce confluent lysis and plaque halos on encapsulated E. Alteration of the amount of EPS produced, either by increasing production on supplemented medium or by knocking out synthesis of either type ereinia the deletion mutants, indicated that phage efficacy is dependent on both of these substances.

erwinia amylovora thesis

Sensitivity effects were monitored by running two reactions simultaneously with identical titres of E. There is the possibility that the rcsB deletion also altered some other component that acts as the cell surface receptor.

The only published complete genome is of Erwinia spp. QPCR may be used further to address current diagnostic issues by providing a more versatile and accurate platform to diagnose and quantify biological titers in sample preparations over traditional culturing methods. Micro Mol Bioi Rev 68, The present work provides information that is critical to the selection of phages developed as biocontrol mixtures or cocktails.


Bennett RA, Billing E. Specialized transduction occurs when host genes are erroneously excised along with the prophage, packaged into a phage virion and carried to another bacterial host.

Biopesticides are also being employed for control of E. Working with Staphylococcus cultures, Twort discovered minute glassy areas that would not grow when subcultured.

Host Exopolysaccharide Quantity and Composition Impact Erwinia amylovora Bacteriophage Pathogenesis

Commonly, this enhanced bacterial virulence occurs due to horizontal gene transfer HGT through lysogeny, via transduction or lysogenic conversion Miao and Miller ; Wagner and Waldor ; Brussow et al.

Physiol Mol Plant Pathol60, Excellent control of shoot blight severity by injected OTC implies that this compound in injectable formulation most likely limits systemic spread of E.

EPS production and plaque morphology. Summing the resolvable segments of BglII gives an estimated genome size of 46, kbp. Infection could be restored by the artificial removal with virion-associated endosialidases that can hydrolyze the capsule.

Absence of lysogeny in wild populations of Erwinia amylovora and Pantoea agglomerans

Roach Looijesteijn et al. The integrated nucleic acid, called a prophage, does not promote virion production thwsis the bacterial viability is maintained.

Defense mechanisms used by bacteria to inhibit phage adsorption.

Colonies which produced a yellow pigmentation on NA were tentatively identified as P. Amplifications were performed with a thermal cycler Techne, UK. The majority, if not all, bacterial genera possess R-M systems Allison and Klaenhammer ; Labrie et al. A few phages in all three families showed apparently reduced progeny production in both mutant backgrounds, although thhesis results were not statistically significant.


Abi systems typically do not provide individual cell resistance to phage infection, rather they amylovor population protection by promoting ” altruistic suicide” of the phage infected bacterium Forde and Fitzgerald b.

Roach one Staphylococcus colony to another. EPS also contributes to the virulence of E. By surveying a diversity of Erwinia spp. Subsequently, field-based trials and in planta bioassays have demonstrated that Erwinia spp. Appl Environ Microbiol69, The results imply that accumulation of injected compound in the crown is a time dependent process, potentially not fully exposing epiphytic bacterial populations to the compound and requiring much earlier times of injection for better accumulation and effect of the compound on the pathogen.

This allowed target amplification of up to four gene targets simultaneously in a single reaction. Differential activities of bacteriophage depolymerase on bacterial polysaccharide: Ann Phytopath Soc Japan 56, Several studies have been conducted on Erwinia spp.

erwinia amylovora thesis

The empty phage capsid remains outside of the bacterial cell.