RcsA/RcsB accumulation suppresses motility and flhD transcription in the lon mutant. (A) Movement of the wild‐type (WT), lon, rcsA, rcsB, lon/rcsA and lon/rcsB mutants and the complementation strain of the lon mutant. Photographs were taken at 48 h post‐incubation on a motility agar plate. (B) The moving distance of the WT, lon, rcsA, rcsB, lon/rcsA and lon/rcsB mutants and the complementation strain of the lon mutant. The diameters of the circle around the inoculation site (mm) were measured at 24 and 48 h post‐inoculation. (C) Relative gene expression of flhD in the five mutant strains compared with the WT grown in MBMA medium for 18 h at 28 °C. The values of the relative fold change are the means of three replicates and the experiment was repeated three times with similar results. Error bars indicate standard deviation.