Cloning and functional analysis of the K+ transporter, PhaHAK2, from salt-sensitive and salt-tolerant reed plants.
We isolated PhaHAK2 cDNAs from salt-tolerant and salt-sensitive reed plants. PhaHAK2 belongs to group II by phylogenetic analysis, and was predicted to be a high-affinity plasma membrane K(+) transporter. Yeast transformed with the PhaHAK2-u from salt-sensitive reed plants (Phragmites australis) had a decreased ability to take up K(+) in the presence of NaCl and showed a higher Na(+) permeability than yeast transformed with PhaHAK2-n or PhaHAK2-e from two salt-tolerant reed plants. These results suggest a possibility that the continuous K(+) uptake by PhaHAK2 and maintenance of high K(+)/Na(+) ratio under salt stress condition is one of the causes of the salt-tolerance in reed plants.
Takahashi
Ryuichi
R
Asian Natural Environmental Science Center, The University of Tokyo, Nishitokyo-shi, Tokyo, Japan.
Nishio
Takayoshi
T
Ichizen
Nobumasa
N
Takano
Tetsuo
T
D000595:Amino Acid Sequence; D001693:Biological Transport, Active / Q000187:drug effects / Q000502:physiology; D003001:Cloning, Molecular / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D004351:Drug Resistance; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry* / Q000187:drug effects / Q000502:physiology*; D011188:Potassium / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D012492:Salts / Q000008:administration & dosage*; D027981:Symporters / Q000737:chemistry* / Q000187:drug effects / Q000502:physiology*
D010940:Plant Proteins; D011994:Recombinant Proteins; D012492:Salts; D027981:Symporters; D011188:Potassium