Author(s): Gimranov, Emil ; Oliveira, Hugo Alexandre Mendes ; Santos, Conceição ; Moura, Luísa ; Azeredo, Joana
Date: 2025
Persistent ID: https://hdl.handle.net/1822/97990
Origin: RepositóriUM - Universidade do Minho
Subject(s): Pseudomonas syringae pv. actinidiae; Bacteriophage; Bacterial canker; Kiwifruit
Pseudomonas syringae pv. actinidiae (Psa) is the causative agent of bacterial canker in kiwifruit (Actinidia spp.). Psa biovar 3 is the most prevalent and virulent, causing frequent and severe outbreaks worldwide. While current treatments have low efficacy, bacteriophages emerge as possible environmentally safe alternative biocontrol agents. In this study, bacteriophage Brt\_Psa3 was isolated from the soil of a kiwifruit orchard in Portugal. Morphologically, Brt\_Psa3 forms clear plaques and has a Podoviral morphotype. The bacteriophage exhibited broad lytic activity against several plant-pathogenic Pseudomonas strains, including Psa isolates. The isolated bacteriophage has a latent period of 100 min, a burst size of 143 particles/cell, and demonstrates stability at different temperatures and pH values found in kiwifruit orchards. In addition, Brt\_Psa3 exhibited tolerance to UVA irradiation during 120 min of incubation. Brt\_Psa3 belongs to the Autographiviridae family and Ghunavirus genus, based on full-genome nucleotide alignment and supported by phylogenetic analysis of structural proteins. The phage contains 51 open reading frames with no antibiotic resistance genes identified, within a genome of 40.509 base pairs. In vitro experiments with kiwifruit leaves demonstrated significant reduction of Psa levels (40\\%) on leaf surfaces, highlighting the bacteriophage's therapeutic potential in managing bacterial canker in kiwifruits.
