A preliminary biocontrol study: Isolation, characterization and genomic analysis of lytic phage TE against Pseudomonas syringae pv. syringae

Traditionally, apricot trees suffering from bacterial canker disease caused by Pseudomonas syringae pv. syringae were treated in orchards through the application of antibiotics or copper-based drugs. However, considering the disadvantages of the long-term use of chemical pesticides and antibiotics, there has been an increasing interest in phages, which have a lytic effect on bacteria, as biopesticides in recent years. In this study, we conducted a comprehensive examination of phage TE, isolated from wastewater in Turkey, from this perspective. Through scanning electron microscopy and phylogenetic analysis, we classified phage TE as belonging to the order Caudovirales and the family Strabovoridae. The phage TE exhibited a robust host lysis efficiency, with 280 infectious phage particles produced per bacterial cell in just 15 min. In experimental trials, treatment with phage TE resulted in an impressive 82% inhibition of bacterial canker disease in apricot leaves, highlighting its effectiveness as a phage therapy agent. Furthermore, phage TE exhibited long-term stability when stored at 4°C without cryoprotectant and displayed tolerance to a wide temperature (−20°C to 50°C) and pH (2–12) range but its tolerance to UV-C was very low. The genome and bioinformatics analyses of P. syringae phage TE have identified distinct protein level differences between other phages of the same species, despite sharing similarities at the nucleotide level. These findings suggest the potential use of phage TE as a biocontrol agent, offering a promising solution to control apricot bacterial canker.