Correlated Phenotypic Transitions to Competence in Bacterial Colonies

TL;DR

This paper models how quorum-sensing signals influence bacterial colonies' transition to competence, revealing anti-correlated behavior among cells and conditions for spatial pattern formation, challenging previous assumptions of uncorrelated transitions.

Contribution

It introduces a model linking quorum-sensing to phenotypic transitions, explaining anti-correlation and proposing new experimental parameters to detect collective signaling effects.

Findings

Effective inhibitory mechanism from quorum-sensing explains anti-correlation.

Model aligns with experimental data showing lack of detected collective signaling.

Conditions for phenotypic spatial pattern emergence are identified.

Abstract

Genetic competence is a phenotypic state of a bacterial cell in which it is capable of importing DNA, presumably to hasten its exploration of alternate genes in its quest for survival under stress. Recently, it was proposed that this transition is uncorrelated among different cells in the colony. Motivated by several discovered signaling mechanisms which create colony-level responses, we present a model for the influence of quorum-sensing signals on a colony of B. Subtilis cells during the transition to genetic competence. Coupling to the external signal creates an effective inhibitory mechanism, which results in anti-correlation between the cycles of adjacent cells. We show that this scenario is consistent with the specific experimental measurement, which fails to detect some underlying collective signaling mechanisms. Rather, we suggest other parameters that should be used to verify the role of a quorum-sensing signal. We also study the conditions under which phenotypic spatial patterns may emerge.