Fig. 5.

Root-mediated transmission of the avirulent pathogen P. syringae pv. syringae (Psy)-elicited systemic acquired resistance (SAR). (A) Schematic representing the experimental design. (B) Disease severity (0 – 5) measured at 7 d after challenge with 10⁸ cfu mL^–1 P. syringae pv. tabaci (Pta) in plants pre-treated with Psy (an avirulent pathogen) at various distances from the SAR-induced plant (cm). Bars represent the mean ± s.e.m. (sample size, n = 5 replications per treatment). Different letters indicate significant differences between treatments (P = 0·05 according to least significant difference). The experiment was repeated three times with similar results.