PT - JOURNAL ARTICLE AU - Matthew Howell AU - Alena Aliashkevich AU - Kousik Sundararajan AU - Jeremy J. Daniel AU - Patrick J. Lariviere AU - Erin D. Goley AU - Felipe Cava AU - Pamela J.B. Brown TI - <em>Agrobacterium tumefaciens</em> divisome proteins regulate the transition from polar growth to cell division AID - 10.1101/412759 DP - 2018 Jan 01 TA - bioRxiv PG - 412759 4099 - http://biorxiv.org/content/early/2018/09/10/412759.1.short 4100 - http://biorxiv.org/content/early/2018/09/10/412759.1.full AB - The mechanisms that restrict peptidoglycan biosynthesis to the pole during elongation and re-direct peptidoglycan biosynthesis to mid-cell during cell division in polar-growing Alphaproteobacteria are largely unknown. Here, we demonstrate that although two of the three FtsZ homologs localize to mid-cell, exhibit GTPase activity and form co-polymers, only one, FtsZAT, is required for cell division. We find that FtsZAT is required not only for constriction and cell separation, but also for the termination of polar growth and regulation of peptidoglycan synthesis at mid-cell. Depletion of FtsZ in A. tumefaciens causes a striking phenotype: cells are extensively branched and accumulate growth active poles through tip splitting events. When cell division is blocked at a later stage, polar growth is terminated and ectopic growth poles emerge from mid-cell. Overall, this work suggests that A. tumefaciens FtsZ makes distinct contributions to the regulation of polar growth and cell division.