Figure 5.

ARF1 Function Is Required for ROP2 Localization and Action.

(A) to (I) Root hair formation in transgenic lines carrying prp3GV and UAS-ROP2-G14V ([A] to [C]). Tip growth defect and strong isotropic expansion were observed in root hairs. Root hair formation in F1 lines carrying prp3GV, UAS-ROP2-G14V, and UAS-ARF1-Q71L is shown ([D] to [F]). Root hair formation in F1 lines carrying prp3GV, UAS-ROP2-G14V, and UAS-ARF1-T31N is shown ([G] to [I]). Note that root hair tip growth is strongly inhibited with no or much reduced isotropic expansion in F1 lines. Overview ([A], [D], and [G]), magnification ([B], [E], and [H]), and CSLM images ([C], [F], and [I]) are shown.

(J) and (K) Expression of the EYFP-ROP2 in Arabidopsis transgenic lines. YFP fluorescence is highly enriched in the apical and basal plasma membranes of the root meristematic cells, and localized to the future site of root hair formation as well as to the root hairs ([K], arrows).

(L) to (N) Colocalization analysis of EYFP-ROP2 ([L]; green) and FM4-64 ([M]; red) in meristematic root epidermal cells of Arabidopsis transgenic lines at 2 h of incubation with 100 μM BFA. Merged image of (L) and (M) is depicted in (N).

(O) EYFP-ROP2 localization in transgenic lines carrying hspGV and UAS-ARF1-WT after heat shock induction (37°C, 2 h, then 22°C, 20 h). Heat shock–induced ARF1 overexpression does not change EYFP-ROP2 localization.

(P) and (Q) EYFP-ROP2 localization in transgenic lines carrying hspGV and either UAS-ARF1-Q71L (P) or UAS-ARF1-T31N (Q) after heat shock induction (37°C, 2 h, then 22°C, 20 h). Note that internalized YFP fluorescence was observed within the cells.

Bars = 100 μm in (A) for (A), (D), and (G); 100 μm in (B) for (B), (E), and (H); 20 μm in (C) for (C), (F), and (I) to (K); and 10 μm in (L) for (L) to (Q).