A Salmonella-specific transcription factor modulates biofilm formation in the environment

FERNANDO C. SONCINI; GONZALO TULIN

Paraná

Congreso; LIV Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2018

SAIB

Salmonella is a food-borne pathogen associated with animal and human infections ranging from gastroenteritis to enteric/typhoid fever. The infections caused by Salmonella constitute an important problem for public health. It is postulated that the ability of Salmonella to survive in the environment and its persistence and transmission between hosts relies to its capacity to form biofilms. This lifestyle?s change, from motile to sessile cells attached to diverse solid surfaces, implies a drastic metabolic rearrangement, and depends on the master transcriptional regulator CsgD. This regulator activates the two major components of extracellular matrix in Salmonella: the curli fimbriae and the exopolysaccharide cellulose. We have previously identified a Salmonella-specific transcription factor, that we named BioR, important for both biofilm production and csgD transcription. To gain insight into the optimal expression conditions of this factor, we generated lacZ fusions allowing us to define that low temperatures and minimal medium are the optimal expression conditions for this regulator. In these conditions, BioR is essential for cell-adhesion and biofilms persistence in vitro. We also determined that this regulator is necessary for the correct cellulose and curli production. Furthermore, we identified target genes that are responsible of this production. A mutant with a deletion of this regulator also affects swimming and swarming motility. Altogether, these results define conditions that trigger the activation of this regulator, that resemble the harsh conditions present in the environment, where Salmonella survive between hosts transmission.