A flagellar accessory protein links chemotaxis to surface sensing.

Bacteria find suitable locations for colonization by sensing and responding to surfaces. Complex signaling repertoires control surface colonization, and surface contact sensing by the flagellum plays a central role in activating colonization programs. Biofilms pose a threat in clinical and industrial settings. Surface sensing is an early step in biofilm formation. Studying surface sensing can help develop strategies for combating harmful biofilms. Here, we use the freshwater bacterium