Functional and Proteomic Analyses Reveal That ScpBXv Is Involved in Bacterial Growth, Virulence, and Biofilm Formation in Xanthomonas campestris pv. vesicatoria

Abstract

Segregation and condensation protein B (ScpB) is essential for replication and segregation in living organisms. Here, we reported the functions of ScpBXv (ScpBlike protein in Xanthomonas campestris pv. vesicatoria) using phenotypic and proteomic analyses. Growth of XcvAscpBXv (ScpBXv knockout mutant) was reduced under both slow and fast growth conditions in rich medium, but comparable to this of the wild-type in plant-mimic conditions. Interestingly, the mutant was significantly less virulent than the wild-type in tomato, indicating that ScpBXv is involved in virulence. To investigate ScpBXv-associated mechanisms, comparative proteomic analyses were carried out and the abundance of 187 proteins was altered. Among them, diverse transcriptional regulators involved in biofilm formation and virulence were abundant in the wild-type. We further showed that biofilm formation of XcvAscpBXv was reduced. This study provides new insights into the functions of ScpBXv in bacterial replication and biofilm formation, which may contribute to the virulence of Xcv.