SinR Controls Enterotoxin Expression in Bacillus thuringiensis Biofilms

• DOI: 10.1371/journal.pone.0087532
• Publication Date: 2014-01-31T22:54:26Z
• Authors: Annette Fagerlund; Thomas Dubois; Ole-Andreas Økstad; Emilie Verplaetse; Nathalie Gilois; Imène Bennaceur; Stéphane Perchat; Myriam Gominet; Stéphane Aymerich; Anne-Brit Kolstø; Didier Lereclus; Michel Gohar
• Keywords: Bacillus thuringiensis; Swarming motility; Cereus

The entomopathogen Bacillus thuringiensis produces dense biofilms under various conditions. Here, we report that the transition phase regulators Spo0A, AbrB and SinR control biofilm formation swimming motility in B. thuringiensis, just as they swarming closely related saprophyte species subtilis. However, microarray analysis indicated contrast to subtilis, does not an eps operon involved exopolysaccharides production, but regulates genes biosynthesis of lipopeptide kurstakin. This is required for was previously shown be important survival host cadaver (necrotrophism). Microarray also revealed regulon contains coding Hbl enterotoxin. Transcriptional fusion assays, Western blots hemolysis assays confirmed controls expression, together with PlcR, main virulence regulator thuringiensis. We show expressed a sustained way small subpopulation biofilm, whereas almost all planktonic population transiently expresses Hbl. gene SinI, antagonist SinR, same hbl, suggesting hbl transcription heterogeneity SinI-dependent. cereus are enteric bacteria which possibly form lining intestinal epithelium. Toxins produced could therefore delivered directly target tissue.