Modes of cell wall growth differentiation in rod-shaped bacteria

•High-resolution techniques allow visualization of PG-biosynthetic complex dynamics.•Labeling with d-amino acid derivatives permits real-time, in vivo, tracking of PG-synthesis.•Division is universally committed to zonal (septal) PG synthesis.•Cell wall elongation follows a dispersed pattern in E. coli while in C. crescentus PG-synthesis concentrates at mid-cell section.•Rhizobiales species exhibit cell elongation by polar cell wall growth.

A bacterial cell takes on the challenge to preserve and reproduce its shape at every generation against a substantial internal pressure by surrounding itself with a mechanical support, a peptidoglycan cell wall. The enlargement of the cell wall via net incorporation of precursors into the pre-existing wall conditions bacterial growth and morphology. However, generation, reproduction and/or modification of a specific shape requires that the incorporation takes place at precise locations for a defined time period. Much has been learnt in the past few years about the biochemistry of the peptidoglycan synthesis process, but topological approaches to the understanding of shape generation have been hindered by a lack of appropriate techniques. Recent technological advances are paving the way for substantial progress in understanding the mechanisms of bacterial morphogenesis. Here we review the latest developments, focusing on the impact of new techniques on the precise mapping of cell wall growth sites.