Polar localisation of PIN1 favours AUX1 activation in the xylem-pole pericycle cells.

A 120-second pulse of AUX1 activation was provided to the pericycle cell marked with an asterisk (A, D, G, J). In simulations with apolar PIN1 and PIN7, this resulted in continued AUX1 activity and auxin accumulation in a specific pericycle cell, regardless of which cell received the pulse (B, E, H, K). By contrast, the pulse only led to persistent activation in xylem-pole pericycle cells in simulations with polar PIN1 and PIN7 (C, F, I, L). Auxin levels are depicted using a ‘DR5-like’ scale.