Fig. 5

Heightened ABA sensitivity in rae1 correlates with ABI5, not CARK1. (A) The abundance of ABI5 protein increased in rae1-b and STOP1OE1, but decreased in stop1-2, regardless of ABA treatment. 5-d old Arabidopsis seedlings (WT, rae1-b, stop1-2, and STOP1OE1) were transferred to fresh plates with or without 10 µM ABA and grown for 20 h. Total protein was separated by SDS-PAGE, followed by Western blotting with an antibody against ABI5. FBA8 was used as a control for equal loading. Grouping is determined by a Student’s t-test (P < 0.05). Error bars represent the standard deviations for five biological replicates. (B) ABI5 Western blotting signals are normalized to WT and presented as column graphs. Error bars represent the standard deviation for five biological replicates. (C) Mutant lines (rae1-b, cark1, abi5-8, abi5-8::rae1-b, and cark1::rae1-b) and WT were grown on half-strength MS medium with or without 1 µM ABA treatment. Daily photographs of seedlings aged between 3 and 7 d are shown (D-E) Column graphs depict the proportion of 7 d old seedlings with cotyledon greening and their fresh weight. Error bars represent the standard deviation for three representative plates. Grouping was determined by one-way ANOVA (P < 0.05, Duncan’s multiple-range test)