Figure 8

The effect of ABA and SA on the transcription-regulating activities of WRKY18, WRKY40 and WRKY60. A. Constructs of reporter and effector genes. The GUS reporter gene is driven by a synthetic promoter consisting of the -100 minimal CaMV 35S promoter and eight copies of the LexA operator sequence. The effector genes were cloned into pTA7002 behind the steroid-inducible promoter. The effector genes encode LexA DBD (LexA), WRKY and LexADBD-WRKY fusion protein, respectively. B. The effect of ABA and SA on the transcription-regulating activity of the WRKY proteins. Progeny from 5 independent transgenic lines for each effector gene were divided into three groups (15-20 plants/group) and sprayed with DEX (20 μM), DEX plus ABA (10 μM) or DEX plus SA (1 mM). Leaves were harvested at 0 and 24 hours after the treatment for assays of GUS activities and the ratios of GUS activities were calculated. Only those progeny that displayed induced expression of the effector genes as determined from RNA blotting following DEX treatment were used in the analyses. The means and errors were calculated from at least 15 positive progeny. The experiments were performed twice with similar results.