(A) Qa-SNARE KNOLLE trafficking route in cytokinesis (Reichardt et al., 2007). ER, endoplasmic reticulum; TGN, trans-Golgi network; CP, cell plate; MVB, multivesicular body; COPI, COPII, AP1/CCV, membrane vesicles with specific coat protein complexes; gnl1, big3, knockout mutations of ARF-GEFs rendering those trafficking steps sensitive to brefeldin A (BFA). (B–D) Subcellular localisation of estradiol-inducible YFP:NPSN11 (B, D; green) and GFP-SNAP33 (C, D; green), and KNOLLE (B–D; red) in big3 (B, C) and gnl1 GNL1BFA-sens. (D) mutant seedling roots treated with 50 µM BFA for 30 min, followed by 50 µM BFA + 20 µM estradiol for 210 min. Note that YFP:NPSN11 (Y:N11) or GFP:SNAP33 (G:S33) accumulates with KNOLLE (KN) at the BFA compartments in BFA-treated big3 mutant whereas YFP:NPSN11 or GFP:SNAP33 colocalises with KNOLLE at the ER in BFA-treated gnl1 GNL1BFA-sens. mutant. Note also no expression of YFP:NPSN11 (Y:N11, B) or GFP:SNAP33 (G:S33, C) without estradiol treatment. Nuclei of overlays (B–D) were counterstained with DAPI (blue). -BFA, mock treatment; +BFA, BFA treatment; -EST, no estradiol treatment. Arrowheads, cell plates; arrows, BFA compartments; asterisks, ER. Scale bar, 5 µm. The experiments were technically repeated three times.