Fig. 8: Silencing of NbPIP1 in N. benthamiana compromises INF1-triggered cell death.

a VIGS of NbPIP1 delayed INF1-mediated HR development. INF1-RFP expressed in NbPIP1, NbSERK3 or GUS -silenced plant leaves and photographs were taken at 2 dpa. Transient expression of INF1-RFP was confirmed by western blot, with anti-RFP antibody labeled “R” and Ponceau S labeled “P”. b Quantification of INF1-mediated cell death in silenced plants. The degree of cell death was divided into three levels: weak cell death, cell death, and no cell death. Asterisks represent significant differences (**P < 0.01) based on Wilcoxon rank-sum test. c INF1-RFP and RFP (as a vector control for INF1-RFP) were expressed in NbPIP1-, NbSERK3- or GUS- silenced plants. Quantification of cell death by measuring electrolyte leakage at 2 dpa. Electrolyte leakage from infiltrated leaf discs was measured as a percentage of leakage from boiled discs. Data are shown as the mean ± SE (n = 8–9 biologically independent samples). Different letters on the graph represent significant differences among samples (One-way ANOVA; P < 0.05). d Relative expression of ten defense-related and PTI marker genes in TRV-GUS and TRV-NbPIP1 leaves expressing INF1 at 2 dpa. The expression level of each gene in TRV-GUS leaves was set at 1. NbEF1α was used as the endogenous control. Data are shown as the mean ± SE of three replicates. Asterisks represent significant differences (**P < 0.01, *P < 0.05) based on Two-tailed Student’s t-test. e qRT-PCR analyzed the expression levels of NbPIP1 gene in N. benthamiana leaves expressing INF1-RFP or RFP at 12, 24, and 36 hpa. NbEF1α was used as the endogenous control. Data are shown as the mean ± SE of three replicates. Different letters on the graph represent significant differences among samples (One-way ANOVA; P < 0.05). All experiments were repeated three times with similar results. Source data are provided as a Source Data file. f Schematic model for the potential mechanism of PlPeL1/PlPeL1-like and LcPIP1 in plant immunity.