Quantification of PR1a expression in N. benthamiana leaves following transient expression of WT and mutant P6 by agroinfiltration. (a) PR-1a transcripts, determined by quantitative PCR, in N. benthamiana leaves harvested 48 h after agroinfiltration. Samples were uninfiltrated leaves (U), and leaves infiltrated with Agrobacterium carrying the following vectors: pGWB17 (EV), P6:CW (CW), P6:D2 (D2), P6:D3 (D3) and P6:D6 (D6). (b) PR-1a transcripts, determined as above. Samples were uninfiltrated leaves (U), and leaves infiltrated with Agrobacterium carrying the following vectors pGWB17 (EV), P6BJIW (BJIW), P6:Δ3–20 (Δ3–20), P6:T1–112 (T1–112) and P6:T1–200 (T1–200). Bars show means±sd (in arbitrary units) of three independent biological samples each comprising three pooled infiltrated leaf sections. Values were normalized to values for EV.