Potassium channel alpha-subunit AtKC1 negatively regulates AKT1-mediated K(+) uptake in Arabidopsis roots under low-K(+) stress.
Potassium transporters play crucial roles in K(+) uptake and translocation in plants. However, so far little is known about the regulatory mechanism of potassium transporters. Here, we show that a Shaker-like potassium channel AtKC1, encoded by the AtLKT1 gene cloned from the Arabidopsis thaliana low-K(+) (LK)-tolerant mutant Atlkt1, significantly regulates AKT1-mediated K(+) uptake under LK conditions. Under LK conditions, the Atkc1 mutants maintained their root growth, whereas wild-type plants stopped their root growth. Lesion of AtKC1 significantly enhanced the tolerance of the Atkc1 mutants to LK stress and markedly increased K(+) uptake and K(+) accumulation in the Atkc1-mutant roots under LK conditions. Electrophysiological results showed that AtKC1 inhibited the AKT1-mediated inward K(+) currents and negatively shifted the voltage dependence of AKT1 channels. These results demonstrate that the 'silent' K(+) channel alpha-subunit AtKC1 negatively regulates the AKT1-mediated K(+) uptake in Arabidopsis roots and consequently alters the ratio of root-to-shoot under LK stress conditions.
Wang
Yi
Y
National Plant Gene Research Centre, China Agricultural University, Beijing, China.
He
Liu
L
Li
Hao-Dong
HD
Xu
Jiang
J
Wu
Wei-Hua
WH
D017360:Arabidopsis / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D018517:Plant Roots / Q000378:metabolism; D011188:Potassium / Q000008:administration & dosage / Q000378:metabolism*; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D021122:Protein Subunits / Q000235:genetics; D051637:Shaker Superfamily of Potassium Channels / Q000235:genetics / Q000502:physiology*; D013312:Stress, Physiological / Q000502:physiology
D029681:Arabidopsis Proteins; C501895:LKT1 protein, Arabidopsis; D015221:Potassium Channels; D021122:Protein Subunits; D051637:Shaker Superfamily of Potassium Channels; C074500:AKT1 protein, Arabidopsis; D011188:Potassium