Different properties of SV channels in root vacuoles from near isogenic Al-tolerant and Al-sensitive wheat cultivars.

Patch-clamp experiments revealed that near isogenic ET8 (Al-tolerant) and ES8 (Al-sensitive) wheat cultivars differed significantly in slow vacuolar channel properties. Under control conditions, whole vacuole currents displayed faster deactivation in ES8. Application of 1.4 microM vacuolar Al3+ caused a 20 mV increase in the activation threshold and slowed activation kinetics in ET8 but not in ES8. Channel density was about 30% higher in ES8 than ET8, and was not altered by 24 h aluminium pre-treatment. However, the activation threshold was reduced in Al-pre-treated ES8. Overall, our data suggests that Alt1 locus may control more than the plasma membrane malate channel in wheat.