Figure 7.

WRKY6 Interacts with the W-Box in the Promoter Region of As(V)-Responsive Transposable Elements.

(A) and (B) Kinetic analysis of LUC activity in N. benthamiana leaves agroinfiltrated with the promoter region of a transposable element At5g35030 fused to LUC (At5g35030p-LUC) (A) or At5g35030p-LUC in which the W-box was mutated (At5g35030pMUT-LUC) (B), alone or with a WRKY6-GFP–overexpressing construct. Leaf discs were incubated in medium with 30 μM As(V) (1.5 h).

(C) ChIP assay of WRKY6-GFP followed by qPCR of the At5g35030 promoter. ChIP assays were performed in N. benthamiana leaf discs agroinfiltrated with At5g35030p-LUC and the At5g35030pMUT-LUC version, with WRKY6-GFP– or GFP-overexpressing constructs. Values represent x-fold enrichment of WRKY6-bound DNA of the At5g35030 promoter in immunoprecipitated samples relative to total input DNA. W-box–containing fragments (At5g35030p-LUC) or mutated W-box–containing fragments (At5g35030pMUT-LUC) of the At5g35030 promoter were qPCR amplified using specific primers. *P < 0.01 (Student’s t test).

(D) ChIP assay of WRKY6-GFP–overexpressing plants, followed by qPCR of the W-box–bearing fragments of transposon promoters. Enrichment was calculated relative to wild-type plants. ACT8 was used as negative control. *P < 0.05 (Student’s t test). Values show mean ± sd.