Fig. 8

Albugo-infected leaves reveal reduced expression of salicylic acid (SA)-regulated genes. a Expression pattern of 671 benzo-(1,2,3)-thiadiazole-7-carbothioic acid (BTH)-inducible genes reported by [66] after inoculation with AcNc2 and AlNc14 over an 8-day time course in MAGIC 107. The data are the average of four experiments. The expression of the same genes during methyl jasmonate treatment [67, 68] are shown for comparison. The relative expression (in log₂ ratios) is colored red for induction and green for repression as illustrated in the color bar. b Altered SA-regulated gene expression in AlNc14 infected Arabidopsis Col-0. Open circles and bars denote the mean ± SE of target gene expression (log₂ transformed normalized relative quantities) in AlNc14 infected tissue from three independent biological replicates with two technical replicates per biological replicate. Closed, black circles denote the individual data points. Different letters indicate significant differences (P < 0.05) in gene expression (Welch Two Sample t-test (PR1, P = 0.395, WRKY54, P < 0.001, NIMIN1, P = 0.072), Wilcoxon rank sum test (WRKY70, P = 0.065) followed by Bonferroni correction). c AlNc14 suppresses BTH and SA induction of PR1. To visualize reporter gene induction and pathogen growth in the same leaf, leaves were collected and stained with magenta-GUS to reveal GUS activity, followed by trypan blue to reveal pathogen growth. Leaves of Col-0 pro(PR1)::GUS were previously inoculated with water or AlNc14 (13 dpi) and infiltrated with DMSO (mock), BTH (200 μM) or SA (200 μM) for 8 hours, then stained. Scale: 5 mm. Leaf images are from the same biological replicate and are representative of the average percentage of staining for each treatment across three independent biological replicates.