Regulation of RAP2.1 expression by ABA and stress. A-B, Northern blot analysis with RNA from 2-week-old seedlings of wild type (A) or aba4-1 (B). re, 3-h of rehydration after 12-h of stress treatments. (C) Expression of the RAP2.1p::GUS reporter gene during stress or ABA treatment. Two-week-old seedlings without any treatment (a) or treated with cold (b), drought (c), high salinity (d), PEG8000 (e) or ABA (f) are shown.