Fig. 1
Residues lining the EDS1 heterodimer cavity mediate immunity signalling. a Crystal structure of EDS1 (blue)–SAG101 (green) showing heterodimer formation chiefly driven by the partner lipase-like domains (light tones) and producing a cavity (magenta mesh) formed by the EP-domains. In the zoom-out, two conserved EDS1 arginine residues lining the cavity are depicted as sticks (brown). b RPP2 resistance phenotypes of 2-week-old control and transgenic lines expressing YFP-cEDS1 or R493A. Hpa EMWA1 infected leaves were stained with trypan blue at 5 dpi. Scale bar represents 100 μm. Images are representative of 24 leaves from two independent experiments. HR, hypersensitive response; fh, pathogen free hyphae. c. Four-week old Arabidopsis plants of the indicated genotypes were infiltrated with Pst AvrRps4 (OD600–0.0005) and bacterial titres determined at 0 and 3 dpi. Bars represent mean of four biological replicates ± SE. Differences between genotypes were determined using ANOVA (Tukey’s HSD, p < 0.005). Similar results were obtained in three independent experiments. d Homology model of EDS1 (blue)–PAD4 (green). Conserved residues in the EP-domains of EDS1 (magenta) and PAD4 (purple) are represented as spheres. EDS1 residues line the heterodimer cavity while PAD4 residues are not part of the cavity. A zoom-out of the sphere-represented residues shows ionic and hydrogen bonds formed by EDS1R493 and equivalent arginine in PAD4R420 with neighbouring residues. e RPP4 resistance phenotypes of 2-week-old control and homozygous transgenic lines expressing wild-type EDS1, PAD4 and mutated arginine variants. Hpa EMWA1 infected leaves were stained with trypan blue at 5 dpi. Scale bar represents 100 μm. The PAD4 R420A image is representative of 18 independent transgenic (T1) plants. HR hypersensitive response, fh pathogen free hyphae
