FIGURE 5.

Nucleus‐localized PpMAPKK5 acts synergistically with PpTGA1 to activate the expression of PpPR promoters. (a) Transient expression of the fusion protein (35S::PpMAPKK5‐GFP) and positive control (35S::GFP) in onion peels was mediated by Agrobacterium tumefaciens infiltration. Green fluorescent protein (GFP) signals were captured using laser‐scanning microscopy (Zeiss), and the white bar represents 70 μm in the horizontal direction. (b) Direct binding of PpTGA1 to PpPR1/PpPR2/PpPR5 promoters was determined according to the ability of Y1H Gold [PpPR1/PpPR2/PpPR5‐AbAi] + PpTGA1‐pGADT7 to grow on SD/−Leu in the presence of 240 μg/L AbA. (c) Dual‐luciferase reporter assay for the transactivation of PpTGA1 and PpMAPKK5 to the PpPR1, PpPR2, and PpPR5 promoters. Activation is indicated by the ratio of LUC:REN; the empty plasmid combined with the promoter of PpPR1, PpPR2 or PpPR5 was set to 1 for the calibration of the ratio. Data represent the mean ± SE of nine independent repeats. ** indicates significant difference between samples (p = 0.01)