Figure 7.

WRKY33 directly activates W-box–containing MYB51 promoter. (A) qPCR analysis of WRKY33 (left) and MYB51 (right) in 9-day-old seedlings co-elicited with 20 μM Dex and Psta for 12 h (left) or 9 and 12 h (right). Data represent the mean ± SE of four replicates of 13–17 seedlings each. Expression values were normalized to that of the housekeeping gene EIF4A1 and relative to those of WT plants. Asterisks and daggers denote statistically significant differences compared to wild-type and myb51 myb122 (left) or wrky33 (right) respectively (P < 0.05, two-tailed t test). Experiments were performed at least twice including in WRKY33-myc (Barco et al., 2019b), producing similar results. (B, C) Nucleotide positions (B) and ChIP-PCR analysis (C) of W-box–containing MYB51 promoter region W bound by WRKY33-flag in wrky33/DEX:WRKY33-flag plants co-elicited with 20 μM Dex or mock solution (0.5% DMSO) and Psta for 9 h. The WRKY33 promoter lacks SMRE motifs. Dashed line represents the fivefold cutoff between weak and strong TF–DNA interactions. Data in (C) represent median ± SE of four biological replicates, each containing approximately 200 seedlings. Experiments were performed twice, producing similar results.