Figure 6.
ABA-responsive gene expression and ABA sensitivity in wild type and strs1 and strs2 mutants. Seedlings were grown on vertical MS plates for 4 d after germination and then transferred to fresh treatment plates. Relative transcript levels were determined by real-time PCR according to the 2−ΔΔCT method using UBQ10 as an internal control (Livak and Schmittgen, 2001). Gene expression was normalized to the wild-type control expression level, which was assigned a value of 1. Data represent the average of four independent experiments ± sd (n = 4). A, Expression of RD26 in wild-type and strs mutant seedlings transferred to MS plates with 100 μm ABA. B, Expression of RD26 in wild-type and strs mutant seedlings transferred to MS plates without ABA. C, Expression of STRS1 and STRS2 in wild-type seedlings transferred to MS plates with 100 μm ABA. D, Expression of STRS1 and STRS2 in wild-type seedlings transferred to MS plates with 300 mm NaCl. E, Expression of STRS1 and STRS2 in aba2-1 (ABA-deficient) mutant seedlings transferred to MS plates with 300 mm NaCl. F, Percentage of germination of wild-type and strs1 and strs2 mutant seedlings after 6 d incubation on MS media containing different concentrations of ABA. Data are mean ± sd (n = 3). Fisher's protected lsd test showed that all strs mutant lines exhibited a significantly higher germination percentage than wild type upon exposure to ABA (P ≤ 0.01).