Optogenetic interrogation of B. subtilis stress-response network dynamics

William Marsh Rice University, Houston TX

Investigators

Abstract

Bacteria must survive environmental stresses such as starvation and antibiotic exposure. These stress-invoking conditions lead to profound changes in bacterial behavior and physiology. Some of these changes have economic and health implications, as stress responses have been linked to the formation of stress-resistant biofilms, virulence, antibiotic tolerance/resistance and persistence. This project focuses on the regulatory pathways that control stress responses in bacteria. The results will shed new light into how bacteria survive stresses, and could lead to new technological advances in synthetic biology and to sorely-needed antimicrobial drugs. A new educational module will be developed for high-school students across the country. This educational module will teach students about bacterial stress responses and why they are important across society. Gene regulatory networks (GRNs) control the fundamental biological process of cell-fate decision-making. It is now clear that GRNs utilize dynamical transcription factor activity patterns as a fundamental regulatory strategy. However, the mechanisms by which GRNs decode dynamical transcription factor signals are generally not understood. This project will use a new optogenetic method to reveal how two model B. subtilis stress-response networks decode time-varying activity patterns of their major transcription factor regulators. It will reveal new mechanisms by which these pathways function and generate new insights into how bacteria survive stresses. The results should also provide new genetic design principles that may underlie cell-fate decisions in higher organisms. As dynamical GRN signaling is conserved to humans, this work will facilitate a new understanding of the rules by which life operates. This project will create a new “Sporograph” educational module to teach students how cells make decisions. An experimental module will be based on an inexpensive version of the laboratory B. subtilis optogenetics system developed here, and allow students to induce visible sporulation and biofilm reporter proteins on bacterial agar plates by applying constant or oscillatory light inputs. The Sporograph module will reach thousands of students during this project, and be setup to expand further in future efforts. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.