Plant Molecular Biology

, Volume 43, Issue 4, pp 515-525

First online:

Characterisation of two distinct HKT1-like potassium transporters from Eucalyptus camaldulensis

  • David J. FairbairnAffiliated withForBio Research Pty LtdDepartment of Botany, University of Queensland
  • , Weihong LiuAffiliated withCSIRO Plant Industry
  • , Daniel P. SchachtmanAffiliated withCSIRO Plant Industry
  • , Sara Gomez-GallegoAffiliated withForBio Research Pty LtdGADI Research Centre, University of Canberra
  • , Sharon R. DayAffiliated withForBio Research Pty LtdDepartment of Veterinary Microbiology and Parasitology, School of Veterinary Medicine, Louisiana State University
  • , Robert D. TeasdaleAffiliated withForBio Research Pty Ltd

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access


Potassium is an essential macronutrient in higher plants. It plays an important physiological role in stoma movements, osmoregulation, enzyme activation and cell expansion. The demand for potassium can be substantial, especially when the plant concerned is a Eucalyptus tree in excess of 50 m tall. We have isolated two cDNAs, EcHKT1 and EcHKT2, from Eucalyptus camaldulensis (river red gum) which are expressed in leaves, stems and roots. These encode potassium transporter polypeptides with homology to the wheat K+-Na+ symporter, HKT1. EcHKT1 and EcHKT2 both complemented the K+-limited growth of an Escherichia coli K+-uptake-deficient triple mutant. EcHKT1 and EcHKT2also mediated Na+ and K+ uptake when expressed in Xenopus oocytes. A comparison of the EcHKT1 and EcHKT2 sequences and their transport properties indicated that these cDNAs represent two K+ transporters with distinct functional characteristics. The functional and structural conservation between these two E. camaldulensis genes and the wheat HKT1 suggests that they play an important, albeit elusive, physiological role.

complementation electrophysiology Eucalyptus camaldulensis potassium transport salinity