Figure 3.

MAPKKK3/5 Are Required for Defense Gene Expression and Disease Resistance.

(A) Pattern-induced FRK1 expression is impaired in mapkkk3 mapkkk5 mutants. Ten-day-old seedlings were sprayed with flg22, chitin, elf18, or Pep2, and samples were harvested at 3 h. ACTIN1 was used as the internal standard. Data are presented as mean ± sd. Different letters indicate significant difference at P < 0.05 (n = 3, one-way ANOVA, Tukey post-test, three independent experiments).

(B) mapkkk3 mapkkk5 mutants display increased susceptibility to P. syringae pv tomato (Pto) DC3000. Plants were infiltrated with Pto DC3000, and bacterial population in the leaf was determined 3 d after inoculation. Data are presented as mean ± sd. Different letters indicate significant difference at P < 0.05 (n ≥ 8, one-way ANOVA, Tukey post-test, three independent experiments).

(C) mapkkk3 mapkkk5 mutants display increased susceptibility to B. cinerea. Disease lesions were recorded 3 d after inoculation with B. cinerea. Lesion size represents mean ± sd. Different letters indicate significant difference at P < 0.05 (n ≥ 14, one-way ANOVA, Tukey post-test, three independent experiments).