Identification and characterization of biofilm formation-defective mutants of Xanthomonas citri subsp. citri

Abstract

Xanthomonas citri spp. citri (Xcc)develops a biofilm structure both in vitro and in vivo. Despite all the progress achieved by studies regarding biofilm formation, many of its mechanisms remain poorly understood. This work focuses on the identification of new genes involved in biofilm formation and how they are related to motility, virulence and chemotaxis in Xcc. A Tn5 library of approximately 6,000 Xcc (strain 306) mutants was generated and screened to search for biofilm formation defective strains. We identified 23 genes whose association with the biofilm formation resulted in a novelty. The analysis of the 23 mutants revealed not only the involvement of new genes in biofilm formation but also reinforced the importance of exopolysaccharide production, motility and cell surface structures in this process. This collection of biofilm defective mutants underscores the multifactorial genetic program underlying the establishment of biofilm in Xcc.