A mechanical signal transmitted by the flagellum controls signalling in Bacillus subtilis. Issue 1 (14th August 2013)

• Record Type: Journal Article
• Authors: Cairns, Lynne S.; Marlow, Victoria L.; Bissett, Emma; Ostrowski, Adam; Stanley‐Wall, Nicola R.
• Is Part Of: Molecular microbiology. Volume 90:Issue 1(2013)
• Page Start: 6
• Page End: 21
• Publication Date: 2013-08-14
• Subjects: Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.12342
• Languages: English
• ISSNs: 0950-382X

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>In the natural environment bacteria predominantly live adhered to a surface as part of a biofilm. While many of the components needed for biofilm assembly are known, the mechanism by which microbes sense and respond to contact with a surface is poorly understood. <italic>Bacillus subtilis</italic> is a Gram‐positive model for biofilm formation. The DegS–DegU two‐component system controls several multicellular behaviours in <italic>B. subtilis</italic>, including biofilm formation. Here we identify the <italic>B. subtilis</italic> flagellum as a mechanosensor that activates the DegS–DegU regulatory pathway. Inhibition of flagellar rotation by deletion or mutation of the flagellar stator gene, <italic>motB</italic>, results in an increase in both <italic>degU</italic> transcription and DegU∼P driven processes, namely exoprotease production and poly‐γ‐<sc>dl</sc>‐glutamic acid biosynthesis. Similarly, inhibition of flagellar rotation by engaging the flagellar clutch or by tethering the flagella with antibodies also promotes an increase in <italic>degU</italic> transcription that is reflective of increased DegU∼P levels in the cell. Collectively, these findings strongly indicate that inhibition of flagellar rotation acts as a mechanical trigger to activate the DegS–DegU two‐component signal transduction system. We postulate that inhibition of flagellar rotation could function as a mechanical trigger to activate bacterial signal transduction cascades in many motile bacteria upon contact with a surface.</p> </abstract>