Control mechanism of osmotic stress response and plant growth by potassium transporter in Arabidopsis

Abstract

A potassium transporter, KUP6 is induced by drought and salinity stress, and abscisic acid (ABA) in Arabidopsis. GUS activity of the KUP6pro:GUS transgenic plants was detected mainly in vascular tissues of root and the localization of KUP6-GFP protein to plasma membrane was observed in 35S:KUP6-GFP transgenic plants by confocal microscopy. We generated kup6kup8 double mutant plants and found that the KUP6 and KUP8 disruption in Arabidopsis resulted in increased formation of the lateral root and root hair. Furthermore, kup6kup8 double mutant showed increased IAA sensitivity and decreased sensitivity to auxin transport inhibitor NPA and ABA in the lateral root growth. KUP6-overexpressing transgenic plants under the control of 35SCaMV promoter showed less transpirational water loss and increased tolerance to drought stress. These data suggested that KUP6 controls both plant growth and stress responses in Arabidopsis.