Figure 4.

Regulation of ABA signaling in Arabidopsis cells by CCPs. (A–D) Arabidopsis aba2-1 protoplasts were analyzed for CCP-dependent induction of an ABA-responsive reporter. Protoplasts were transfected with DNA of several expression cassettes, including an ABA-responsive LUC reporter, a constitutively expressed GUS reporter gene for normalization, and the effector genes encoding RCAR11 and ABI2. The protoplasts were exposed to the ligands ABA and CCPs (symbols as indicated in A–D) for 18 h prior to analysis of reporter expression. The ABA response was expressed as fold induction relative to the value of protoplasts transfected with empty vector for the RCAR11 expression cassette (E.V.; filled squares) in the absence of ligands, which was 2.8 × 103 relative light units per relative fluorescence. Each data point represents the mean ± SD of three independent transformations plus three technical replicates per data point. (C) *P < 0.05 (one-way ANOVA) comparing reporter induction achieved by 30 mM CCP5 to that of 30 mM CCP4.