Fig. 1: PdCDIE1 and its homologs from two other postharvest fungal pathogens exhibit plant cell death-inducing activity.

a Schematic representation of primary structure features of four candidate Pd effector proteins. b PdCDIE1/PDIP_06490, but not three other Pd proteins, triggered cell death in Nicotiana benthamiana. N. benthamiana leaves were infiltrated with Agrobacterium tumefaciens carrying indicated Pd genes, GFP (negative control), or BAX (positive control), and photos were taken at 4 days post infiltration (dpi). c Electrolyte leakage assays were performed in N. benthamiana leaves to quantify cell death in (b). d, e Phenotypes and PI staining of citrus (Citrus sinensis) fruit (d) and apple (Malus domestica) fruit (e) upon the expression of indicated genes. White triangles in PI staining micrographs indicate dead cells. Bars, 25 μm. f Electrolyte leakage assays in citrus fruit (d). g Electrolyte leakage assays in apple fruit (e). h Phylogenetic analysis of PdCDIE1 and its homologs from other fungal organisms. Phylogenetic tree was generated by the MEGA5 software using the neighbor-joining method. i Cell death phenotypes of N. benthamiana leaves expressing PITC_010880 (abbreviated as PITC) from P. italicum and PEX2_090640 (abbreviated as PEX2) from P. expansum. In b, d, e, i, the experiments were repeated at least three times with similar results. In c, f, g, j, data were shown as mean ± standard deviation (SD) of three biological replicates, and differences were assessed using two-tailed t-test (***, p < 0.001; **, p < 0.01; ns no significant).