Fig. 4

Mutation of all four phosphorylation sites weakens ERF8-induced cell death. (a) The nuclear localization of YFP-tagged ERF8 is not altered in the S103A and S103A mutants. Shown is transient expression of ERF8 in N. benthamiana 1 dpi. Scale bar = 50 μm. (b) Cell death triggered by ERF8 (W), ERF8^S103A, ERF8^S103D, ERF8^{quad A} and ERF8^{quad D} at 4 dpi. ++: strong cell death, +: weak/delayed cell death, −: no cell death. (c) Photos of leaves infiltrated with ERF8 variants at 4 dpi were analyzed for cell death severity. The fraction of cell death to healthy leaf tissue from each image was quantified using the ImageJ macro disease image-based quantification (PIDIQ) assay (LaFlamme et al., 2016). Shown are the mean ± SD (n = 3). Asterisks indicate statistical significance from ERF8 wt (student’s t test; p < 0.01)