biostudies-literatureBasaran MBAGEPEMBOe72187https://www.ebi.ac.uk/biostudies/studies/S-EPMC8963879biostudies-literatureUnknown11During colony growth, complex interactions regulate the bacterial orientation, leading to the formation of large-scale ordered structures, including topological defects, microdomains, and branches. These structures may benefit bacterial strains, providing invasive advantages during colonization. Active matter dynamics of growing colonies drives the emergence of these ordered structures. However, additional biomechanical factors also play a significant role during this process. Here, we show that the velocity profile of growing colonies creates strong radial orientation during inward growth when crowded populations invade a closed area. During this process, growth geometry sets virtual confinement and dictates the velocity profile. Herein, flow-induced alignment and torque balance on the roeLifeLarge-scale orientational order in bacterial colonies during inward growth.PMC8963879Installation Grant 3275Young investigator awardYaman YIVetter RBasaran MYuce TCKocabas AfalseLarge-scale orientational order in bacterial colonies during inward growth.During colony growth, complex interactions regulate the bacterial orientation, leading to the formation of large-scale ordered structures, including topological defects, microdomains, and branches. These structures may benefit bacterial strains, providing invasive advantages during colonization. Active matter dynamics of growing colonies drives the emergence of these ordered structures. However, additional biomechanical factors also play a significant role during this process. Here, we show that the velocity profile of growing colonies creates strong radial orientation during inward growth when crowded populations invade a closed area. During this process, growth geometry sets virtual confinement and dictates the velocity profile. Herein, flow-induced alignment and torque balance on the ro2022-01-01T00:00:00Z2022 Mar2025-04-27T01:07:50.469Z2025-04-06T18:10:08.205ZS-EPMC89638793525425710.7554/eLife.72187