Salicylic Acid Accumulation in Barley Is Pathogen Specific but Not Required for Defense-Gene Activation

Abstract

Barley (Hordeum vulgare) seedlings were inoculated with the biotrophic pathogen Erysiphe graminis f. sp. hordei, the biotrophic nonhost pathogen E. graminis f. sp. tritici, and the necrotrophic nonhost pathogen Pseudomonas syringae pv. syringae. The levels of free salicylic acid and of salicylic-acid conjugates remained low after infection with E. graminis f. sp. hordei or E. graminis f. sp. tritici while they increased after inoculation with P. syringae pv. syringae. Pathogenesis-related proteins PR1, PR3 (chitinase), PR5 (thaumatin-like), and PR9 (peroxidase) accumulated after inoculation with all three pathogens.

Keywords

• powdery mildew
• PR proteins