Isolation of Erwinia amylovora Bacteriophage from Aerial Parts of Apple Trees

Abstract

Populations of Erwinia amylovora bacteriophage greater a spreading translucent halo and a smaller plaque without a than 106 plaque-forming units (PFU) per gram of tissue were halo. Thirty-five bacterial isolates, consisting of nine genera, isolated without enrichment from diseased aerial parts of 18 species, and 15 strains of E. amylovora were typed; the apple trees during the summer of 1975. Three phage isolates phages lysed only E. amylovora. The burst size of the three were selected from different geographical locations. Two isolates was 40 to 50 PFU per cell. The phages could be stored types of plaques were produced; a clear-centered plaque with at 4 C and-20 C but lost titer when stored at 24 C.

Expression of bacteriophage ϕEa1h lysozyme in Escherichia coli and its activity in growth inhibition of Erwinia amylovora

“…AJ278614) and three ORFs were identified: one encoded an exopolysaccharide depolymerase (Kim & Geider, Ritchie & Klos (1977).…”

“…Bacteriophages have been used for identification of plant-associated bacteria, to determine capsulation of Erw. amylovora cells and also for disease control (Billing, 1960;Bernhard et al, 1993;Schnabel & Jones, 2001); they have been isolated from the soil in the vicinity of diseased trees (Ritchie & Klos, 1977) and from diseased tissue of host plants (Okabe & Goto, 1963). A bacteriophage was applied to pear slices and it delayed symptom development after inoculation with Erw.…”

Phage therapy for plant disease control with a focus on fire blight

“…Depending on whether one or multiple host bacterium isolates or species are used for phage isolation, one can obtain phages that are either host specific or display a wide host response range. Ritchie and Klos [55,56] used a single host strain for isolation of phages and reported that the tested E. amylovora phages isolated from aerial parts of apple trees had a narrow host range, as they were able to lyse only isolates of E. amylovora and the closely related saprophyte, P. agglomerans. On the other hand, Gill et al [57] found that phages isolated using a mixture of multiple host strains had a broader host range.…”

“…Since the 1970s, more and more phages have been isolated and subsequently characterized in detail [54][55][56][57][58][59][60][61]. However, until recently, numerous efforts to control fire blight in orchards failed because phage populations declined in the absence of E. amylovora [23,56,58].…”

“…On the contrary, there were no detectable prophages in any of the six Ea29-7 phageresistant isolates; therefore, in this case resistance was thought to be the result of bacterial mutation. Based on early studies [54,55] it has been shown that the virulence of E. amylovora is attenuated in phageresistant bacteria. A similar phenomenon was also reported for Pseudomonas morsprunorum (Wormald) Yong et al [72].…”