Genomic surveillance of epiphytic Pseudomonas syringae identifies highly virulent strains from phylogroup 2d widespread in UK orchards

In perennial crops, a dynamic reservoir of potentially pathogenic bacteria occurs within the plant surface ecosystem. We examined the role of epiphytic strains of Pseudomonas syringae on cultivated cherry trees and nearby woodland plants in the spread of bacterial canker disease of Prunus. Genomic surveillance of Pseudomonas syringae over 2 years and in four regions of the UK, revealed the presence of ten diverse phylogroups of the species on symptomless leaves. Expansion of the genomic surveillance of the leaf surface environment will enable researchers to view management of crop plants on a landscape scale.