title: Potassium Transporter KUP7 Is Involved in K(+) Acquisition and Translocation in Arabidopsis Root under K(+)-Limited Conditions.
abstract: Potassium (K(+)) is one of the essential macronutrients for plant growth and development. K(+) uptake from environment and K(+) translocation in plants are conducted by K(+) channels and transporters. In this study, we demonstrated that KT/HAK/KUP transporter KUP7 plays crucial roles in K(+) uptake and translocation in Arabidopsis root. The kup7 mutant exhibited a sensitive phenotype on low-K(+) medium, whose leaves showed chlorosis symptoms compared with wild-type plants. Loss of function of KUP7 led to a reduction of K(+) uptake rate and K(+) content in xylem sap under K(+)-deficient conditions. Thus, the K(+) content in kup7 shoot was significantly reduced under low-K(+) conditions. Localization analysis revealed that KUP7 was predominantly targeted to the plasma membrane. The complementation assay in yeast suggested that KUP7 could mediate K(+) transport. In addition, phosphorylation on S80, S719, and S721 was important for KUP7 activity. KUP7 was ubiquitously expressed in many organs/tissues, and showed a higher expression level in Arabidopsis root. Together, our data demonstrated that KUP7 is crucial for K(+) uptake in Arabidopsis root and might be also involved in K(+) transport into xylem sap, affecting K(+) translocation from root toward shoot, especially under K(+)-limited conditions.
authors: State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, National Plant Gene Research Centre (Beijing), China Agricultural University, Beijing 100193, China.
authors: Min
authors: M
authors: Han
authors: State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, National Plant Gene Research Centre (Beijing), China Agricultural University, Beijing 100193, China.
authors: Wei
authors: W
authors: Wu
authors: State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, National Plant Gene Research Centre (Beijing), China Agricultural University, Beijing 100193, China.
authors: Wei-Hua
authors: WH
authors: Wu
authors: State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, National Plant Gene Research Centre (Beijing), China Agricultural University, Beijing 100193, China. Electronic address: yiwang@cau.edu.cn.
authors: Yi
authors: Y
authors: Wang
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017136:Ion Transport; D009154:Mutation; D018517:Plant Roots / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport
chemical_list: D029681:Arabidopsis Proteins; C000607348:KUP7 protein, Arabidopsis; D015221:Potassium Channels; D011188:Potassium
keywords: Arabidopsis thaliana; K(+) deficiency; K(+) translocation; K(+) uptake; KUP7