Abstract
A potassium transporter, KUP6 is induced by drought and salinity stresses, and abscisic acid (ABA) in Arabidopsis. GUS activity of the KUP6pro:GUS transgenic plants was detected mainly in vascular tissues and guard cells. The KUP6-GFP protein was localized at plasma membrane in the 35S:KUP6-GFP transgenic plants. We generated kup6kup8 double mutant and found that the KUP6 and KUP8 disruption in Arabidopsis resulted in increased lateral root (LR) formation. Furthermore, the kup6kup8 showed increased IAA sensitivity and decreased sensitivities to auxin transport inhibitor NPA and ABA in the LR growth. To understand the function relationship between GORK and the KUPs in LR formation, we generated the kup6kup8gork triple mutant and analyzed the phenotypes. The triple mutant showed enhanced auxin response and impaired sensitivities to NPA and ABA in LR formation as compared with those in the kup6kup8 double mutant. KUP6-overexpressing transgenic plants showed less transpirational water loss and increased tolerance to drought stress as compared with those in the wild-type plants. These data suggested that KUP6 controls both plant growth and stress responses in Arabidopsis.
