Figure 8.

Exogenous NHP primes plants for enhanced pathogen-induced (defense) metabolite accumulation. A and E, Camalexin accumulation. B and F, Pip accumulation. C and G, Accumulation of total SA, that is, the sum of unconjugated SA, SA-SAG, and SGE. Accumulation of each of the three SA forms is primed by NHP (Supplemental Figure S5). D and H, Val accumulation. Accumulation of the other BCAAs, Leu and Ile, is also primed by NHP (Supplemental Figure S6). Plants were watered with 10 mL of 1 mM NHP or 10 mL of H₂O (1° treatment), and leaves challenge-inoculated with Psm (p) or mock-infiltrated (m) with 10 mM MgCl₂ 1 d later (2° treatment). The leaves of a third set of plants were left untreated (−). Metabolite levels in leaves were determined 12 h after the 2° treatment. Bars represent means ± sd of four biological replicates (n = 4). Different letters denote significant differences (P < 0.05, Kruskal–Wallis H test). A–D, Experiment with Col-0, fmo1, and npr1-3. E–H, Independent experiment with Col-0, ald1, sid2-1, and npr1-3.