Identifying the design principles of flagella biosynthesis programs in single bacteria during deep stationary phase

• Applicant: Dr. Alina Guse
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 460260981

In nature, after a brief exponential growth, bacteria spend most of their time in deep stationary phase (DSP). However, most research focusses on the transient exponential phase with optimal growth conditions, and thus overlooks a major aspect of bacterial behavior. I am interested in characterizing the growth advantage phenotype in stationary phase (GASP). Early experiments discovered that GASP cells are in fact constantly selected during DSP by acquiring random mutations that confer a growth advantage compared to their parental strain, and that those cells display highly dynamic transcriptional programs and are not static. Surprisingly, the GASP phenotype has been so far exclusively studied at the population level that masks cell-to-cell variability and temporal fluctuations of individual cellular behavior. I propose to characterize the dynamics of a specific transcriptional program during DSP at the single-cell level. Isolated GASP cells of Salmonella by the Cluzel lab exhibited an unexpected transcriptional program of one of the most prominent bacterial organelles, the flagellum. More specifically, these Salmonella mutants are capable of synthetizing energetically costly flagella even during DSP, whereas wild-type (WT) Salmonella are usually incapable to do so. Thus, we hypothesize that flagellum biosynthesis has been re-programmed in GASP Salmonella by mutations that alter the transcriptional dynamics of the WT program to permit the coexistence of flagellar synthesis and bacterial growth in DSP. I will use state-of-the-art single-cell and gene expression analyses to unravel the underlying molecular mechanisms that allow bacteria to achieve such a re-programming.

• DFG Programme: WBP Fellowship
• International Connection: USA
• Host: Professor Dr. Philippe Cluzel