F113 produces a second flagellar apparatus. (A) Gene cluster organization of P. fluorescens F113 second flagellum compared to Azotobacter vinelandii DJ. Flagellar genes in A. vinelandii are located in two separated clusters compared to the single cluster in F113. ORFs arrows are at scale. Numbers indicate chromosome coordinates in both strains. (B) Swimming motility of P. fluorescens F113 wild type and a modified strain overexpressing the second flagellum master regulator flhDC operon. Increased motility is shown by a larger halo after 18 h. incubation.