National Plant Gene Research Centre, China Agricultural University, Beijing, China.
Cell Res. 2010 Jul;20(7):826-37. doi: 10.1038/cr.2010.74. Epub 2010 Jun 1.
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.
钾转运体在植物的钾吸收和转运中起着至关重要的作用。然而，到目前为止，人们对钾转运体的调控机制知之甚少。在这里，我们发现一个 Shaker 样钾通道 AtKC1，由拟南芥低钾（LK）耐受突变体 Atlkt1 中克隆的 AtLKT1 基因编码，在 LK 条件下显著调节 AKT1 介导的钾吸收。在 LK 条件下，Atkc1 突变体保持其根生长，而野生型植物停止其根生长。AtKC1 的损伤显著增强了 Atkc1 突变体对 LK 胁迫的耐受性，并显著增加了 Atkc1 突变体在 LK 条件下根中的钾吸收和钾积累。电生理结果表明，AtKC1 抑制了 AKT1 介导的内向钾电流，并负移 AKT1 通道的电压依赖性。这些结果表明，“沉默”钾通道α亚基 AtKC1 负调控拟南芥根中 AKT1 介导的钾吸收，从而改变 LK 胁迫条件下根/茎的比例。
