Figure 6.

SA-induced expression of PR-1a∷GUS fusions in transgenic tobacco. Plants were transformed with constructs encoding a CaMV 35S promoter∷GUS fusion (35S), a wild-type (WT) 902-bp PR-1a promoter∷GUS fusion, and 902-bp PR-1a promoter∷GUS fusions containing the mutations shown in Figure 5. Four leaf discs from each plant were floated on water (H₂O) or 1 mm SA for 48 h before GUS activity was measured, or four leaf discs were taken from the untreated transgenic plants (Leaf). The number of transgenic lines used is indicated (n). The bars represent the GUS activity of all transgenic plants per construct relative to that of wild type treated with 1 mm SA (100%). Error bars represent the sem.