CCA1::LUC luminescence in roots of ELF4-ox scion into a, elf4–1 (n=4) and b, elf4–2 (n=3) rootstocks. Water instead of luciferin was added to the wells containing ELF4-ox shoots. CCA1::LUC luminescence in elf4–1 rootstocks with c, WT (n=8) and d, ELF4 Minigene (ELF4MG) (n=10) scions. WT scions do not express reporters and water instead of luciferin was added to the wells containing ELF4MG shoots. a-d, Schematic drawings depicting the different scion/rootstock combinations are shown above each graph. e, Circadian time course analyses of ELF4 mRNA expression in roots of WT, elf4–1 and ELF4-ox scion and elf4–1 rootstocks. f, Luminescence of LHY::LUC rhythms in elf4–1 roots after injection in shoots of purified ELF4 (n=4) or GFP proteins (n=8) and elf4–1 roots as a control (n=6). g, Representative image showing the lack of fluorescence signals in roots of WT scion and WT rootstock. h, Representative image showing fluorescence signals in roots of ELF4-ox scion into elf4–1 rootstock. Scale bar: 100 μm. i, Western-blot analysis of ELF4-GFP protein accumulation (arrows) in roots of ELF4-ox-GFP scion (E4ox) grafted into elf4–1 rootstock (e4–1) (two pools of independent grafting assays, #1 and #2, are shown). Asterisks denote non-specific bands. j,
CCA1::LUC luminescence in elf4–2 rootstocks grafted with ELF4-x3GFP scions (n=5). Water instead of luciferin was added to the wells containing ELF4-x3GFP shoots. a-f, j, Data are represented as the means + SEM. k, Protein features of various plant mobile proteins. The “n” values refer to independent samples. a-j, Two biological replicates were performed for all experiments, with measurements taken from distinct samples grown and processed at different times.