(A–B) CBF1 and DREB2A bind to the promoter of COR78, IAA5 and IAA19. (A) CBF1 binds to the promoter of COR78, IAA5 and IAA19 in 10-day-old light-grown whole seedlings. (B) DREB2A binds to the promoter of COR78, IAA5 and IAA19 in the roots of 10-day-old light-grown seedlings that were desiccated for 1h. Sonicated chromatin was immunoprecipitated either with or without anti-GFP antibody. Fold induction was normalized to no antibody and wild-type controls. Data represents mean with standard error from two independent biological replicates with two technical replicates for CBF1 and three independent biological replicates for DREB2A. Differences are significant at p<0.01(**), p<0.005 (***), and p<0.08 (#). (C, D, E) CBF1 and DREB2A directly regulate IAA5 and IAA19 transcription. (C) Estradiol regulated DREB2A overexpression (Est.≫DREB2A) induces IAA5, IAA6 and IAA19 expression. Data represent means with standard error from three independent biological replicates. Significant at p<0.005 (***) and p<0.05 (**). (D) Expression of DREB2A, IAA5 and IAA19 in CBF2DN line after 1 h desiccation. Differences are significant at p<0.05 (*) and p<0.005 (***). (E)
IAA5 and IAA19 levels in dreb2a-dreb2b double mutant after 1 h desiccation. Differences are significant at p<0.005 (***) and p<0.01 (**) Student’s t-test.