Effect of Bas2108-2109 Two Component System on Multicellular Behavior of Bacillus anthracis

Bacillus anthracis, a threating bioterror agent causing anthrax is endowed with 41 Two-Component Systems (TCS). TCS in B. anthracis shares significant similarity with TCS present in Bacillus subtilis. We have recently reported BAS2108-2109 TCS as an ortholog of DegUS TCS and it was shown to be important in the regulation of proteases in B. anthracis. DegUS TCS have been implicated for their role in the regulation of multicellular behavior in other bacteria. In this study, the role of BAS2108-2109 TCS in regulating multicellular behavior in B. anthracis was investigated. B. anthracis overexpressing BAS2109 was found to exhibit retarded swarming motility, biofilm and pellicle formation indicating its role in complex colony formation. Overexpression of BAS2109 also augmented sporulation in B. anthracis, although it reduced spore germination. Invasion and adherence of the B. anthracis overexpressing BAS2109 was higher as compared to the wildtype, further suggesting the role of this system in the pathogenesis of B. anthracis. Together, our results demonstrate the role of BAS2108- 2109 in controlling various multicellular behavioral responses in B. anthracis.