AtJAC1 interacts physically and genetically with GRP7 in the regulation of flowering. A, CoIP assay confirming the interaction between AtJAC1 and GRP7 in vivo. AtJAC1-FLAG together with GRP7-GFP or GFP were cotransfected into tobacco leaves, IP was performed with anti-GFP antibody, and immunoblotting was done with anti-FLAG antibody. B, BiFC assay showing the interaction between AtJAC1 and GRP7 in the cytoplasm in Arabidopsis protoplasts. Hoechst staining of nuclei is shown. Bars = 10 μm. C, CoIP assay of the interaction between AtJAC1 and GRP7 in the cytoplasm. Nuclear and cytoplasmic protein fractions were isolated from Col and grp7-1 plants separately. IP was performed with anti-AtJAC1 antibody, and immunoblotting was done with anti-GRP7 antibody. IgG(H), IgG H chain. D and E, AtJAC1 regulates flowering through GRP7. Morphological phenotypes (D) as well as rosette leaf numbers and FLC mRNA levels (E) are shown in Col, atjac1-1, grp7-1, and atjac1-1 grp7-1 double mutants. Tukey’s HSD test was performed for E. Letters with or without ′ represent different groups; different letters indicate statistically significant differences within groups.