Potassium channel α-subunit AtKC1 negatively regulates AKTl-mediated K^＋ uptake in Arabidopsis roots under Iow-K^＋ stress  

作　　者：Yi Wang Liu He Hao-Dong Li Jiang Xu Wei-Hua Wu 

机构地区：[1]State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), National Plant Gene Research Centre, College of Biological Sciences, China Agricultural University, no. 2 West Yuan Ming Yuan Road, Beijing 100193, China [2]National Institute of Biological Sciences, Beijing 102206, China [3]Department of Biochemistry, University of Alberta, Alberta, Canada [4]Crop Science Research Institute, Chinese Academy of Agricultural Science, Beijing 100081, China

出　　处：《Cell Research》2010年第7期826-837,共12页细胞研究（英文版）

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）.

摘　　要：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.

关 键 词：ARABIDOPSIS potassium channel low-K^＋ stress AKT1 AtKC1 Arabidopsis potassium channel low-K＋ stress AKT 1 AtKC 1 

分 类 号：S571.1[农业科学—茶叶生产加工] Q73[农业科学—作物学]