title: The potassium transporter OsHAK21 functions in the maintenance of ion homeostasis and tolerance to salt stress in rice.
abstract: The intracellular potassium (K(+) ) homeostasis, which is crucial for plant survival in saline environments, is modulated by K(+) channels and transporters. Some members of the high-affinity K(+) transporter (HAK) family are believed to function in the regulation of plant salt tolerance, but the physiological mechanisms remain unclear. Here, we report a significant inducement of OsHAK21 expression by high-salinity treatment and provide genetic evidence of the involvement of OsHAK21 in rice salt tolerance. Disruption of OsHAK21 rendered plants sensitive to salt stress. Compared with the wild type, oshak21 accumulated less K(+) and considerably more Na(+) in both shoots and roots, and had a significantly lower K(+) net uptake rate but higher Na(+) uptake rate. Our analyses of subcellular localizations and expression patterns showed that OsHAK21 was localized in the plasma membrane and expressed in xylem parenchyma and individual endodermal cells (putative passage cells). Further functional characterizations of OsHAK21 in K(+) uptake-deficient yeast and Arabidopsis revealed that OsHAK21 possesses K(+) transporter activity. These results demonstrate that OsHAK21 may mediate K(+) absorption by the plasma membrane and play crucial roles in the maintenance of the Na(+) /K(+) homeostasis in rice under salt stress.
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Shen
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Like
authors.initials: L
authors.lastname: Shen
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Zhenxing
authors.initials: Z
authors.lastname: Shen
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Jing
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Hongliang
authors.initials: H
authors.lastname: Ge
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Jiangzhe
authors.initials: J
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Wenhua
authors.initials: W
authors.lastname: Zhang
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D006706:Homeostasis; D017136:Ion Transport; D009154:Mutation; D012275:Oryza / Q000235:genetics* / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000502:physiology; D018520:Plant Shoots / Q000235:genetics / Q000502:physiology; D011188:Potassium / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology; D054712:Salinity; D055049:Salt Tolerance; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000378:metabolism; D052584:Xylem / Q000235:genetics / Q000502:physiology
chemical_list: D027682:Cation Transport Proteins; D010940:Plant Proteins; D012965:Sodium Chloride; D012964:Sodium; D011188:Potassium
keywords: HAK transporter; Na+/K+ homeostasis; Oryza sativa; salinity stress