Figure 1. Intraspecific variation of HR-like cell death inB. nigra accessions. HR-like cell death induced by egg wash in nine accessions. Treatments were applied on the abaxial side of the leaf as drops. Egg-wash induced symptoms were scored in severity: 0, no visible response; 1, brown spots underneath egg wash-treated spot, only visible at abaxial side leaf; 2, cell death also visible at adaxial side of leaf, spot smaller than 2 mm diameter; 3; cell death covering the size of the egg wash-treated spot; 4, cell death spreading lesion beyond the treated spot. Controls (MES buffer) did not induce visible symptoms (not shown). For each treatment/accession combination N=10. Different letters indicate significant difference between accessions (Kruskall-Wallis test, p -value < 0.05).