Figure 3.

Cortical microtubule array reorientation by auxin is mediated by the SCF^TIR1/AFB-Aux/IAA-ARF nuclear signaling pathway. The inhibition of nuclear auxin signaling by the conditional expression of a dominant-negative mutant of the Aux/IAA protein AXR3/IAA17 (HS:axr3-1) (A) or by blocking protein translation with cycloheximide (CHX, 50 μM) (B) prevented the auxin-induced reorientation of cortical microtubules. The GFP fluorescence is depicted in grayscale. The graphs show the average percentage of cells in each category from three experiments. Error bars indicate standard deviation (only the lower bar is shown for clarity). Total cell numbers are given above each graph. The frequencies of cells with longitudinal arrays were compared using t tests, p = 0.0176 (*) in A and p = 0.0007 (***) in B.