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

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