FIGURE 1.

Accumulation of SA, 2,3-DHBA, and 2,5-DHBA after challenge with avirulent pathogens. The data represent the averages ± S.D. of three replicate samples. Metabolite levels were significantly different in Col-0 samples compared with corresponding samples from the mutants at p < 0.05 (*) and p < 0.01 (**). The experiments were repeated twice with similar results. Total (A) and free (B) levels of phenolic metabolites were measured in leaves of 4-week-old plants that were syringe-infiltrated with 10 mm MgCl₂ (mock) or with 5 × 10⁶ colony-forming units/ml Pst DC3000 avrRpm1 (Pst avrRpm1). C, accumulation of total phenolic metabolites was determined in 3-week-old plants 4 days after treatment with water (mock) or spray inoculation with 10⁵ spores/ml of avirulent H. arabidopsidis isolate Cala2 (recognized by R gene RPP2 in Col-0).