The AKT2 potassium channel mediates NaCl induced depolarization in the root of Arabidopsis thaliana.

Soil salinization is a major cause of plant stress, partly due to the physicochemical similarities between Na(+) and K(+). Na(+) ions compete with K(+) ions for their transport into root cells. However, the point of Na(+) entry remains unidentified. Here, I have applied the Electrical Penetration Graph as a method for whole plant electrophysiology in order to test if (a) root exposure to NaCl induces depolarization waves that propagate from root to shoot via the phloem, and if (b) the electrophysiological effects of root exposure to NaCl require expression of the potassium channels AKT1 and/or AKT2. The data suggest that AKT2 subunit containing K(+) channels mediate NaCl-induced depolarization of root cells, and that this depolarization does not propagate to leaves via the phloem.