Figure 4 : Detection of LesA movement in grapevine leaves.

From: The Type II Secreted Lipase/Esterase LesA is a Key Virulence Factor Required for Xylella fastidiosa Pathogenesis in Grapevines

Figure 4

(A) Grapevine leaf showing the three segments, each 1 to 2 cm in the radial direction, used to detect LesA: I (inside), M (middle) and O (outside). (B) Viable Xff cell assay of leaf segment (n = 3) extracts revealed ~10-fold reduction in the bacterial population at the leaf edges (outside) than at the center (inside). The bacterial titration was carried out using a standard curve of five dilutions (Fig. S4; *One-way ANOVA test; R2 = 0.9817; p < 0.01). (C,D) The amount of LesA detected in grapevine leaves differs slightly in the inside and outside segments (C) (***Mann-Whitney test; p = 0.1). However, the relative abundance of LesA per number of Xff cells (D) is significantly greater in the outside area than in middle and inside segments (**One-way ANOVA test; p < 0.05), suggesting that the secreted LesA is moving from the Xff-crowded inside area to the symptomatic leaf extremities where the bacteria is scarcely present. This experiment was conducted twice with similar results. Picture of leaf was taken by Rafael Nascimento.