Bsi functions with BphP1 to negatively regulate swarming motility. (A to F) Swarming motility of the wild-type P. syringae pv. syringae B728a strain and Δbsi strain, along with Δlov and Δlov-bsi strains (A and B), ΔbphOP1 and ΔbphOP1 Δbsi strains (C and D), or Δbsi(pHbsi), ΔbphOP1, and ΔbphOP1(pHbsi) strains (E and F) were evaluated under white-light (A, C, and E) and dark (B, D, and F) conditions. Values, error bars, statistical analyses, and experimental replication are as described in the legend to Fig. 3.