Fig. 5

Expression of JA- and SA-related genes. a Experimental design. b Expression of B. nigra genes was measured by QPCR and normalized to the housekeeping gene BnSAND. Leaf discs (blue circle) were collected on 5-week-old B. nigra plants pretreated for 3 days with P. brassicae egg extract (EE) or Xanthomonas campestris pv. raphani (Xcr) and further challenged with P. brassicae (P) feeding for 24 h at the site of treatment. Untreated plants (CTL) or plants exposed to a single stress were included. Means (± SE) of three technical replicates are shown. These experiments were repeated at least twice with similar results. Different letters indicate significant differences (two-way ANOVA followed by Tukey’s honest significant difference test, P < 0.05)