Fig. 3.

OsSPK1 interacts with the small GTPase OsRac1. (A) Identification of the OsRac1-binding region in OsSPK1 by a yeast two-hybrid assay. (B) Yeast two-hybrid assays of OsSPK1 and OsRac1 mutants. (A and B) Yeast growth on selective plates without histidine [His (−)] and with 10 mM 3-AT indicates a positive interaction. (C) GFP-OsRac1 mutants and OsSPK1-Myc were transiently coexpressed in N. benthamiana leaves. Co-IP was carried out with anti-GFP antibody, and the proteins were detected by Western blot with anti-GFP and anti-Myc antibodies. (D) BiFC assay of OsRac1 mutants and OsSPK1 in N. benthamiana leaves. Expression of these genes was driven by the CaMV 35S promoter. Empty vector served as a negative control. FM4-64 was used as a plasma membrane marker. Enlarged images of the boxed areas are shown, Right. (Scale bars, 25 μm.)