Transcriptome Analysis Reveals Cross-Kingdom Virulence Factors in Erwinia persicina Cp2

Erwinia persicina is a well-documented plant pathogenic bacterium, causing soft rot in various plant hosts. There are rare previous reports that it is associated with animal diseases. In this study, we used an alfalfa root infection model and a mouse model via gavage administration of E. persicina strain Cp2. Strain Cp2 was pathogenic on both alfalfa and mice. On alfalfa, Cp2 primarily caused leaf spot and etiolation. Mice exhibited moderate lesions in their liver, stomach and kidney tissues, with inflammation in the liver and kidney after gavage. Furthermore, viable Cp2 cells were successfully reisolated from mouse faeces at different time periods after gavage. Transcriptome analysis revealed that the 34 bacterial differentially expressed genes (DEGs) in Cp2 in response to infecting both alfalfa and mice were predominantly enriched in pathways related to bacterial adhesion, biofilm and motility. Bap was identified as a key virulence gene contributing to cross-kingdom pathogenicity of Cp2. The results provide a solid foundation for the subsequent functional validation of the virulence factors of this cross-kingdom pathogenic bacterium.