Transient transcriptional regulatory activities of WRKY42, WRKY13, and WRKY45-2 analyzed by the chimeric reporter/effector assay in rice protoplasts. REN was used as the internal control to standardize the difference of the transformation ratio. Data represent mean (three biological repeats with each repeat having three replicates) ± sd. The letters a and b indicate a significant difference was detected between effector WRKY13, WRKY42, or WRKY45-2 and control effector YFP at P < 0.05 and P < 0.01, respectively. A, WRKY13 directly suppressed LUC driven by full-length or truncated WRKY42 promoters. B, WRKY13 and WRKY45 regulated each other’s promoter, and WRKY42 and WRKY45-2 regulated their own promoters.