Characterization of streptomycin-induced persister cells in Erwinia pyrifoliae

Abstract

Antibiotic persistence represents a transient physiological state in which a small subpopulation of bacteria survives lethal antibiotic exposure without acquiring genetic resistance. These persister cells are increasingly recognized as a major cause of recurrent infections. Erwinia pyrifoliae, the causal agent of black shoot blight in apple and pear, poses a serious threat to fruit production, yet its ability to persist under antibiotic stress remains poorly understood. In this study, it was demonstrated that E. pyrifoliae forms non-heritable persister cells upon exposure to lethal concentrations of streptomycin. Killing assays revealed a characteristic biphasic survival pattern, while tolerance assays showed that persister cells exhibited markedly enhanced survival under both antibiotic and oxidative stress conditions compared with the normal cell population. Transcriptomic analysis identified a distinct persistence-associated transcriptional program, characterized by the strong induction of toxin–antitoxin systems, global stress-response regulators, membrane stabilization factors, and dormancy-related pathways, accompanied by the repression of growth- and metabolism-related functions. These results establish antibiotic persistence as a survival strategy in E. pyrifoliae under streptomycin stress and provide a mechanistic framework to explain disease recurrence and sporadic black shoot blight outbreaks in orchards. The identified pathways represent potential molecular targets for improving the management of phytopathogenic bacteria under antibiotic pressure.