Figure 9.

Callose deposition induced by Escherichia coli O157:H7 and Salmonella enterica Typhimurium 14028s varies among the lettuce genotypes Lollo Rossa and Red Tide. The second leaf of 2.5- to 3-week-old plants was infiltrated with either 1 x 10⁸ CFU/mL bacterial inoculum or water as a control. The area of callose deposition was measured in three plants for each treatment and the experiment was conducted independently four times. Results are shown as mean (n = 12 ± standard error) area of callose deposition normalized with the corresponding mock treatment value. Pairwise mean comparisons (callose deposits produced by Lollo Rossa versus Red Tide) were performed with a two-tail Student’s t-test (*< 0.001 and **p < 0.0001).