Role of the lipoprotein VacJ/MlaA in the physiology and virulence of the plant pathogen Xanthomonas citri subsp. citri

Xanthomonas citri subsp. citri (Xcc) is the important causal agent which causes citrus canker in citrus crops. In this study, a mutant strain with an in-frame deletion removed nucleotides 134 to 1017 of the vacJ gene was con-structed to reveal the role of VacJ in the physiology and virulence from Xcc. Mutation of vacJ resulted in the decrease in biofilm formation ability in glass tubes and on leaf surfaces, swarming motility, bacterial growth in planta and virulence on the host plant mandarin orange compared with the wild-type strain. Our results show that the VacJ plays an important role in the virulence of X. citri subsp. citri that is associated with the regulation of biofilm formation and swarming motility. The results provided evidence that the lipoprotein VacJ plays an important role in the virulence of the plant pathogen X. citri subsp. citri.