Figure 5.

Effect of transient overexpression of MpABI1 on ABA-induced gene expression. A, Constructs used for transient assays. The wheat Em promoter (Em-p) fused to the GUS reporter gene was used as a reporter construct for the detection of ABA-induced gene expression (Marcotte et al., 1989). The rice actin promoter (Actin-p) fused to MpABI1, MpABI-d1, MpABI1-d2, or MpABI1-G298D was used as an effector construct to see their effects on ABA-induced GUS gene expression. The rice ubiquitin promoter fused to the luciferase gene was used as a control construct (data not shown). Plasmid DNAs with these constructs were cobombarded into M. polymorpha or P. patens cells using the PDS-1000He particle delivery system, and the cells were then incubated with or without ABA (for details, see “Materials and Methods”). Protein fractions prepared from the cells were used for GUS and LUC assays, and the relative GUS activity-to-LUC activity ratios (GUS/LUC) are represented in B to D. B, Effect of different concentrations of ABA on Em-GUS expression in M. polymorpha cells. C, Effect of MpABI1 overexpression on 1- μm ABA-induced Em-GUS expression in M. polymorpha cells. D, Effect of overexpression of wild-type MpABI1 and deletion mutants MpABI1-d1, MpABI1-d2, and MpABI1-G298D on ABA-induced Em-GUS expression in P. patens.