Figure 3.

WRKY33 Is Essential for CPK5-Mediated Induction of Camalexin Biosynthesis.

(A) Est-induced CPK5^CA-HA expression in Est:CPK5^CA-HA plants leads to the transcriptional activation of WRKY33. Two-week-old Est:CPK5^CA-HA seedlings were treated with 10 μM Est. WRKY33 transcript levels at the indicated time points were analyzed by RT-qPCR.

(B) to (D) WRKY33 is required for CPK5^CA-induced production of camalexin and the activation of camalexin biosynthetic genes. Two-week-old Est:CPK5^CA-HA and Est:CPK5^CA-HA/wrky33-2 seedlings were treated with 10 μM Est. Camalexin production was quantified at 24 h posttreatment (B). The expression of CPK5^CA-HA was analyzed by immunoblotting (IB) with anti-HA antibody, and total protein loading was assessed by Ponceau S staining (PS; [C]). The transcript levels of CYP79B2, CYP71A13, and PAD3 at the indicated time points were analyzed by RT-qPCR (D). FW, fresh weight.

Different letters above the columns in (A) and (B) indicate significant differences (P < 0.05), as determined by one-way ANOVA. Significant differences at specific time points in (D) are indicated by asterisks (*, P < 0.05), as determined by Student’s t test. Error bars in (A), (B), and (D) indicate sd (n = 3 biological repeats), and small circles represent individual data points.