Host Specificity of the Bacteriophage PP35 Is Directed by a Tail Spike Interaction With Bacterial -Antigen, Enabling the Infection of Alternative Non-pathogenic Bacterial Host.

is a recently emerged virulent bacterial potato pathogen that poses a major threat to world agriculture. Because of increasing antibiotic resistance and growing limitations in antibiotic use, alternative antibacterials such as bacteriophages are being developed. bacteriophages recently re-ranked as a separate family, such as phage PP35 described in this work, are the attractive candidates for this bacterial biocontrol. PP35 has a very specific host range due to the presence of tail spike protein PP35 gp156, which can depolymerize the -polysaccharide (OPS) of . The OPS structure, →2)-β-D-6-deoxy-D-altrose-(1→, is so far unique among soft-rot , though it may exist in non-virulent environmental . The phage tail spike depolymerase degrades the shielding polysaccharide, and launches the cell infection process. We hypothesize that non-pathogenic commensal bacteria may maintain the population of the phage in soil environment.