Figure 6.

Pep1 triggers a systemic immune signaling from the root to the shoot. (a) A schematic diagram for the definition of local (1°) and systemic (2°) tissues. Root in the black box was treated with peptide elicitor and shoot in red box was used for gene expression analysis. (b–e) Pep1 application in roots induces systemic PR1 (b), PR5 (c), PDF1.2 (d), and PDF1.3 (e)expression in shoot. (f) Pretreatment of Pep1 in roots enhances flg22-induced callose deposition in shoots. Roots of 10-d-old plate-grown seedlings were pretreated with 1 μM Pep1 or H₂O for 24 hours, then the shoot of seedlings was treated with 1 μM flg22 or H₂O for another 24 hours before callose deposition staining. Callose deposits in cotyledons were measured using ImageJ. Data are shown as mean ± s.e.m (n = 8). (g) Pep1 application in roots induces PROPEP expression in roots but not in shoots. (h) Pep1 application in shoots induces PROPEP expression in shoots. (i) Pep1 application in roots induces ZAT12 expression in shoot RBOHD/F-dependent manner. (b–e, g–i) The lower half roots of 1-week-old seedlings grown on 1/2MS plate were treated with 1 μM Pep1 or H₂O for 24 hours, roots were then cut off for seedlings for mRNA isolation and RT-qPCR analysis of gene transcription levels. Different letters indicate a significant difference with others (P < .01, n.s., no significant differences, Student’s t-test, n = 3). The experiments were repeated three times with similar results.