Open filament tracks drive Bacteroidota gliding motility

Bacteria of the phylum Bacteroidota glide across surfaces using adhesins that attach to the substratum and are propelled along the cell body by an underlying track. The track is currently thought to form a single closed loop around the cell. Here we use 3D super-resolution tracking of single adhesin molecules in Flavobacterium johnsoniae to characterize adhesin movements in unprecedented detail. Our data overturn multiple aspects of the single closed loop model by showing that adhesins follow non-repeating trajectories that cross, make sharp turns, and exhibit reversals and circular paths. We develop a new model for Bacteroidota gliding in which the track network comprises multiple independently moving, open filaments. This supramolecular organization resembles that of other moving bacterial filaments such as MreB and FtsZ, suggesting that open filaments are a common organising principle in the bacterial cytoskeleton.