FIGURE 7.

(a) Influence of extracellular methyl 3‐hydroxymyristate (3‐OH MAME) application on quorum sensing (QS)‐dependent phenotypes, biofilm formation, exopolysaccharide EPS I production, and swimming motility of Ralstonia pseudosolanacearum strains OE1‐1, ΔphcB, ΔphcR, and ΔphcQ. (b) Expression levels of the QS‐dependent genes epsB, ralA, and fliC in the same strains. (a) For the biofilm formation and EPS I production assays, R. pseudosolanacearum strains were grown in quarter‐strength M63 or quarter‐strength M63 medium containing 0.1 µM 3‐OH MAME. For the swimming motility assay, 5‐μl aliquots of cell suspensions at 5 × 10⁵ cfu/ml were added to the centre of plates containing quarter‐strength M63 medium solidified with 0.25% agar, and the swimming‐area diameters were measured at 24 hr postinoculation. Three replicate experiments conducted using independent samples with seven technical replicates per biofilm formation experiment and five technical replicates per EPS I production or swimming motility experiment produced similar results. The results of a representative experiment are shown. Bars indicate standard errors. Asterisks indicate values significantly different from those of controls without 3‐OH MAME (p < .05, t test). (b) Total RNA was extracted from bacterial cells grown until OD₆₀₀ = 0.01. Bars indicate standard errors. Asterisks indicate values significantly different from those of OE1‐1 (p < .05, t test)