Figure 3.

ARF1 Function Is Required for Root Hair Tip Growth in Arabidopsis Trichoblast Cells.

(A) Expression of the GFP reporter gene under the control of the trichoblast-specific PRP3 promoter. Note that GFP expression is only observed in root hair–forming cells (T) but not in atrichoblast cells (A).

(B), (G), and (L) Trichoblast-specific overexpression of ARF1-WT in transgenic lines carrying prp3GV and UAS-GUS, which is indicated by GUS staining.

(C) to (K) Trichoblast-specific expression of ARF1-Q71L ([C], [D], [H], and [I]) and ARF1-T31N ([E], [F], [J], and [K]). Note the graded root hair tip growth defects. Weak lines have very short root hairs ([C] to [F]), whereas strong lines have almost no root hair formation ([H] to [K]).

(M) to (O) Trichoblast cells in ARF1–overexpressing lines (M), ARF1-Q71L–expressing lines (N), and ARF1-T31N–expressing lines (O). Images were obtained by CSLM.

Bars = 20 μm in (A) and (M) to (O), 250 μm in (B), and 100 μm in (C) and all other panels.