Figure 1.

PAD4 Is Involved in Pathogen-Triggered SIS to Herbivory Independent of SA Production and the COI1 JA-Signaling Module.

Lower Arabidopsis rosette leaves were inoculated with a sterile 10 mM MgSO₄ control solution (dark-gray bars) or Psm ES4326 cfa6 suspension (OD₆₀₀ = 0.2; light-gray bars). Four days later, the inoculated leaves were removed and newly hatched T. ni larvae were placed on the upper rosette leaves. Larval weight gain was measured after 7 d of feeding. For each experiment, weight gain data were normalized to the weight gain of larvae feeding on mock-inoculated wild-type (Col-0) plants. The bars represent the means (±se) of relative weight gain from two independent experiments with n = 36 larvae per treatment per experiment.

(A) Relative larval weight gain in wild-type (Col-0), sid2-2, and pad4-1 plants (ANOVA; treatment, P < 0.05; genotype, P < 0.05; treatment × genotype, P < 0.05).

(B) Relative larval weight gain in wild-type (Col-0) and coi1-1 plants (ANOVA; treatment, P < 0.05; genotype, P < 0.05, treatment × genotype, not significant). Letters above the bars signify statistically significant differences among groups (Tukey, P < 0.05).