Identification and disruption of a plant shaker-like outward channel involved in K+ release into the xylem sap.
SKOR, a K+ channel identified in Arabidopsis, displays the typical hydrophobic core of the Shaker channel superfamily, a cyclic nucleotide-binding domain, and an ankyrin domain. Expression in Xenopus oocytes identified SKOR as the first member of the Shaker family in plants to be endowed with outwardly rectifying properties. SKOR expression is localized in root stelar tissues. A knockout mutant shows both lower shoot K+ content and lower xylem sap K+ concentration, indicating that SKOR is involved in K+ release into the xylem sap toward the shoots. SKOR expression is strongly inhibited by the stress phytohormone abscisic acid, supporting the hypothesis that control of K+ translocation toward the shoots is part of the plant response to water stress.
Gaymard
F
F
Biochimie et Physiologie Moléculaire des Plantes, INRA/CNRS URA 2133/Agro-M/UM II, Montpellier, France.
Pilot
G
G
Lacombe
B
B
Bouchez
D
D
Bruneau
D
D
Boucherez
J
J
Michaux-Ferrière
N
N
Thibaud
J B
JB
Sentenac
H
H
D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis; D029681:Arabidopsis Proteins; D003001:Cloning, Molecular; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D018514:Plant Structures / Q000378:metabolism; D015221:Potassium Channels / Q000737:chemistry*; D012333:RNA, Messenger / Q000378:metabolism; D018749:RNA, Plant / Q000378:metabolism; D051637:Shaker Superfamily of Potassium Channels
D029681:Arabidopsis Proteins; D010940:Plant Proteins; D015221:Potassium Channels; D012333:RNA, Messenger; D018749:RNA, Plant; C114544:SKOR protein, Arabidopsis; D051637:Shaker Superfamily of Potassium Channels