Fig. 4

Comparison of PCD (programmed cell death) induction kinetics in Ren6 and Ren7 genotypes. All data and micrographs were collected 2 dpi and at least 100 germinated spores were scored following trypan blue staining for estimation of PCD. (a) Relative levels of PCD in powdery mildew-penetrated epidermal cells of an F1 microvine population segregating for Ren6 and Ren7. Each data point is the mean ± SE of at least two biological replicates. (b) Proportion of penetrated epidermal cells that show either effective PCD (no secondary hyphae), ineffective PCD (secondary hyphae produced) or no PCD following powdery mildew penetration in four individual VpF1 lines shown in (a). For comparison, two additional microvine lines were included – a susceptible line lacking any R genes and a resistant line containing the Run1 locus. Results are shown from one experiment, but the experiment was repeated twice with the same results. (c–f) Micrographs showing examples of effective PCD (c, d) and non-effective PCD (e, f). Epidermal cells that have undergone PCD, as shown by the uptake of trypan blue, are indicated with an asterisk while secondary hyphae are indicated by white arrows