Role of Specific Quorum-Sensing Signals in the Regulation of Exopolysaccharide II Production within Sinorhizobium meliloti Spreading Colonies
Figure 10
Contributions of EPS II to colony spreading.
Surface spreading of S. meliloti Rm8530 (wild type), MG32 (sinI), MG170 (sinR), Rm1021 (expR), Rm9034 (wggR), Rm9030-2 (wgaA), and Rm9032 (wgdA) on 0.4% agar and 20-fold-diluted LB medium (top row). Crude EPS (harvested from the spreading colonies of Rm8530) or its high or low molecular weight fractions (20 µl) were spotted onto the plate surfaces, into which 3.5 µl of tested bacteria were added. The amount of supplied EPS II represents ∼1/2–1/7 of the amount of EPS II that is produced by a 3-day old single swarming colony. Plates were incubated for 2–3 days at 30°C before photographing.