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 potassiu...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 Atlktl, significantly regulates AKTl-mediated K^＋ uptake under LK conditions. Under LK conditions, the Atkcl mutants maintained their root growth, whereas wild-type plants stopped their root growth. Lesion of AtKC1 significantly enhanced the tolerance of the Atkcl mutants to LK stress and markedly increased K^＋ uptake and K^＋ accumulation in the Atkclmutant 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 α-subunit AtKC1 negatively regulates the AKTl-mediated K^＋ uptake in Arabidopsis roots and consequently alters the ratio of root-to-shoot under LK stress conditions.展开更多
基金Acknowledgments We thank Dr Emily Liman （University of Southern California, USA） for providing the pGEMHE vector for the Xenopus oocyte experiments. We also thank Dr Richer Gaber （Northwestern Uni- versity, USA） for providing the yeast mutant strain with K＋ transport deficiency. We are grateful to Dr Rainer Hedrich （University of Wurzburg, Germany） for critical discussion. This work was supported by the National Natural Science Foundation of China （grant no. 30830013 to WHW）, the Beijing Municipal Education Commission （grant no. YB20081001901 to WHW） and the Program of Introducing Talents of Discipline to Universities （grant no. B06003 to WHW）.
文摘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 Atlktl, significantly regulates AKTl-mediated K^＋ uptake under LK conditions. Under LK conditions, the Atkcl mutants maintained their root growth, whereas wild-type plants stopped their root growth. Lesion of AtKC1 significantly enhanced the tolerance of the Atkcl mutants to LK stress and markedly increased K^＋ uptake and K^＋ accumulation in the Atkclmutant 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 α-subunit AtKC1 negatively regulates the AKTl-mediated K^＋ uptake in Arabidopsis roots and consequently alters the ratio of root-to-shoot under LK stress conditions.
