Figure 4.

A G-Box Motif in MFT Promoter Mediates Spatial Regulation of MFT in Response to ABA.

(A) Schematic diagram of MFT(P2)-GUS and MFT(P6)-GUS constructs where MFT 5′ upstream sequences containing ABREs were transcriptionally fused with the GUS gene (left panel). The right panel shows the mutagenesis of the RY repeat and the G-box in the ABRE that is located 700 bp upstream of the ATG start codon.

(B) GUS staining in germinating seeds of the transformants containing MFT(P2)-GUS, MFT(P6)-GUS, and their derived constructs with the mutated RY repeat (mRY) and G-box motif (mGbox). Seeds from T3 homozygous plants with a single insertion of the transgene for each construct were analyzed, and representative images are shown. Germinating seeds mock treated or treated with 10 μM ABA, which were at the same developmental stage, were stained 12 or 24 h after stratification, respectively.

(C) GUS staining in germinating seeds of MFT(P2)-GUS, 35S:ABI3-6HA MFT(P2)-GUS, 35S:ABI5-6HA MFT(P2)-GUS, and 35S:ABI5-6HA MFT(P2)-GUS-mGbox. Germinating seeds treated with 1 and 3 μM ABA, which were at the same developmental stage, were stained 24 h after stratification.

(D) GUS staining in germinating seeds of MFT(P2)-GUS, abi3-1 MFT(P2)-GUS, abi5-1 MFT(P2)-GUS, and abi3-1 abi5-1 MFT(P2)-GUS. To examine GUS expression in seeds at the same developmental stage, MFT(P2)-GUS and abi5-1 MFT(P2)-GUS treated with 10 μM ABA were stained 24 h after stratification, while other germinating seeds mock treated or treated with 10 μM ABA were stained 12 h after stratification.