The motility-matrix production switch in Bacillus subtilis -- a modeling perspective

TL;DR

This paper models the regulatory switch controlling motility and matrix production in Bacillus subtilis, highlighting the role of upstream noise in triggering phenotype switching, and distinguishes sources of stochasticity affecting the process.

Contribution

It provides a detailed modeling framework for the SinR-SlrR switch and identifies upstream noise as a key factor in spontaneous switching events.

Findings

Intrinsic fluctuations in SinI synthesis are insufficient to cause switching.

Switching is likely triggered by upstream noise from the Spo0A phosphorelay.

The model distinguishes different sources of stochasticity in phenotype switching.

Abstract

Phenotype switching can be triggered by external stimuli and by intrinsic stochasticity. Here, we focus on the motility-matrix production switch in Bacillus subtilis. We use modeling to describe the SinR-SlrR bistable switch its regulation by SinI, and to distinguish different sources of stochasticity. Our simulations indicate that intrinsic fluctuations in the synthesis of SinI are insufficient to drive spontaneous switching and suggest that switching is triggered by upstream noise from the Spo0A phosphorelay.