Phage biocontrol to combat Pseudomonas syringae pathogens causing disease in cherry

Area of Science:

• Plant Pathology
• Microbiology
• Biotechnology

Background:

• Bacterial canker, caused by Pseudomonas syringae pathovars, significantly impacts Prunus species like cherry trees.
• Existing copper-based treatments face challenges due to environmental concerns and pathogen resistance.
• There is a need for sustainable and natural alternatives for managing bacterial plant diseases.

Purpose of the Study:

• To isolate and characterize bacteriophages with biocontrol potential against bacterial canker pathogens.
• To evaluate the efficacy of bacteriophages as a sustainable alternative to chemical treatments.
• To assess the safety of bacteriophages towards non-target beneficial bacteria.

Main Methods:

• Isolation of seventy bacteriophages from cherry tree environments (soil, leaf, bark).
• Host range assessment against Pseudomonas syringae pathovars (Pss, Psm1, Psm2) and Pseudomonas fluorescens.
• Genome sequencing of thirteen selected phages to determine genetic relatedness and identify potential virulence factors.
• In vivo bioassays to evaluate disease reduction efficacy of individual phages and phage cocktails.

Main Results:

• Seventy phages were isolated, demonstrating lysis of various P. syringae pathovars.
• Phages showed specificity, not infecting beneficial Pseudomonas fluorescens.
• Genome sequencing revealed five distinct phage clades with no identified toxins or lysogeny genes.
• Selected phages significantly reduced bacterial canker progression in vivo.

Conclusions:

• Bacteriophages represent a promising, specific, and safe biocontrol strategy for bacterial canker in cherry trees.
• Phage cocktails offer enhanced efficacy for disease management.
• This research supports the development of phage-based agricultural solutions as a sustainable alternative to conventional methods.