Characterization of the extracellular matrix of biofilms formed by Xanthomonas citri subsp . citri strains with different host ranges

Xanthomonas citri subsp. citri ( Xcc ) causes citrus bacterial canker (CBC) on several Citrus species. Xcc requires bacterial aggregation and biofilm formation to colonize the host plant. Those biofilms are dependent on the environmental condition and their structures differ according to the host range of the Xcc strain. Herein, we have visualized and evaluated the extracellular structures produced by Xcc strains with different host range at early stages of biofilm formation, in mature biofilms and during planktonic growth. Moreover, the presence of these structures was related to the transcription of quorum sensing, flagellar and fimbrial genes. Our results demonstrate that the variation in biofilm formation between Xcc strains is associated with expression of fimbrial and flagellar genes which in some cases is dependent on a quorum sensing system.