Figure 3. The rsmA mutant produces high levels of pectinolytic enzymes which constitute the majority of the proteins that are secreted.

Wild-type (wt), rsmA⁻, and rsmB⁻ cells were grown in minimal medium containing either 0.2% glucose (glc) or 0.2% polygalacturonic acid (PGA). Cell-free supernatants were then collected at various timepoints to evaluate protein content. A. The growth curves obtained for each strain and growth condition. The arrows indicate the timepoints used for collecting supernatant samples. B–D. Activity of polygalacturonase (Peh) (B), pectate lyases (Pel) (C), and proteases (Prt) (D) in supernatant samples collected from the exponential phase (white) and the early stationary phase (black) for each strain indicated. The average activity values for three independent experiments are represented. Error bars indicate the standard deviation values. E. Proteins in the wild-type and rsmA⁻ strain culture supernatants were concentrated20 times by acetone precipitation and separated by SDS PAGE. M indicates molecular weight marker.