Cloning and functional expression in Saccharomyces cereviae of a K+ transporter, AlHAK, from the graminaceous halophyte, Aeluropus littoralis.
High-affinity K(+) transporters play an important role in K(+) absorption of plants. We isolated a HAK gene from Aeluropus littoralis, a graminaceous halophyte. The amino acid sequence of AlHAK showed high homology with HAK transporters obtained from Oryza sativa (82%) and Hordeum vulgare (82%). When expressed in Saccharomyces cereviae WDelta3, AlHAK performed high-affinity K(+) uptake with a K(m) value of 8 muM, and the growth of transformants was dramatically inhibited by 150 mM Rb(+) and 150 mM Cs(+) but less affected by 300 mM Na(+). AlHAK may thus improve the capacity of plants to maintain a high cytosolic K(+)/Na(+) ratio at high salinity.
Su
Qiao
Q
Department of Bioscience and Biotechnology, School of Environmental & Biological Science & Technology, Dalian University of Technology, Dalian, Liaoning province, 116024, PR China. dsuqiao@dlut.edu.cn
Feng
Shuyang
S
An
Lijia
L
Zhang
Gaohua
G
D003001:Cloning, Molecular; D005816:Genetic Complementation Test; D006863:Hydrogen-Ion Concentration; D026901:Membrane Transport Proteins / Q000378:metabolism*; D010940:Plant Proteins / Q000302:isolation & purification / Q000378:metabolism*; D006109:Poaceae / Q000187:drug effects / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D020539:Sequence Analysis, Protein; D012964:Sodium / Q000494:pharmacology; D014170:Transformation, Genetic / Q000187:drug effects
D026901:Membrane Transport Proteins; D010940:Plant Proteins; D012964:Sodium; D011188:Potassium