Multidimensional Characterization of Novel Phage UCB24 Targeting Erwinia amylovora

Abstract

This study evaluates the novel bacteriophage UCB24 as an eco-friendly biocontrol agent against Erwinia amylovora, the bacterial pathogen responsible for fire blight. Following purification, UCB24 was characterized for its optimal multiplicity of infection (MOI), infection kinetics, and environmental stability across diverse pH and temperature ranges. Microtitration assays and scanning electron microscopy (SEM) confirmed distinct morphology of the phage and its potent capacity to disrupt E. amylovora biofilms. Whole-genome sequencing and phylogenetic profiling identified UCB24 as a genetically distinct relative of four known phages. Furthermore, protein-protein interaction analyses revealed a strong binding affinity between the phage lysin and the hosts N-acetylmuramic-acid 6-phosphate etherase, uncovering the precise molecular mechanism driving targeted host destruction. In vivo plant trials demonstrated exceptional protective efficacy in Apple cv. Gala (88.61%) and Quince cv. Esme (81.37%), significantly outperforming traditional copper treatments under severe baseline pathogen pressure. Consequently, UCB24 represents a highly effective and sustainable biopesticide for managing fire blight in susceptible orchard ecosystems.