Bacillus subtilis Hfq: A role in chemotaxis and motility

Hfq is a global post-transcriptional regulator that modulates the translation and stability of target mRNAs and thereby regulates pleiotropic functions, such as growth, stress, virulence and motility, in many Gram-negative bacteria. However, comparatively little is known about the regulation and function(s) of Hfq in Gram-positive bacteria. Recently, in Bacillus subtilis, a role for Hfq in stationary phase survival has been suggested, although the possibility of Hfq having an additional role(s) cannot be ruled out. In this study we show that an ortholog of Hfq in B. subtilis is regulated by the stress sigma factor, sigma^B, in addition to the stationary phase sigma factor, sigma^H. We further demonstrate that Hfq positively regulates the expression of flagellum and chemotaxis genes (fla/che) that control chemotaxis and motility, thus assigning a new function for Hfq in B. subtilis.