Figure 2.

Influence of ralA deletion on the quorum sensing of Ralstonia solanacearum. Expression of phcB and phcA in R. solanacearum OE1‐1 and ralA‐deleted mutant (ΔralA) strains (a) and methyl 3‐hydroxymyristate (3‐OH MAME) purified from the R. solanacearum OE1‐1 and ΔralA strains (b). The R. solanacearum strains were grown in one‐quarter‐strength M63 medium (to OD₆₀₀ = 0.3). Total RNA was then extracted from the bacterial cells. The rpoD gene was used as an internal control for quantitative real‐time polymerase chain reaction. The gene expression levels are presented relative to the rpoD expression level. The experiment was conducted at least twice using independent samples, with similar results. Results for a single representative sample are provided. Values are presented as the mean ± standard deviation of three replicates. Asterisks indicate values that are significantly different from those of OE1‐1 cells (P < 0.05, t‐test). Synthetic 3‐OH MAME was used as a positive control. The arrows indicate the peaks corresponding to 3‐OH MAME.