Molecular cloning and expression of the Na+/H+ exchanger gene in Oryza sativa.
Na+/H+ exchanger catalyzes the countertransport of Na+ and H+ across membranes. We isolated a rice cDNA clone the deduced amino acid sequence of which had homology with a putative Na+/H+ exchanger in Saccharomyces cerevisiae, NHX1. The sequence contains 2330 bp with an open reading frame of 1608 bp. The deduced amino acid sequence is similar to that of NHX1 and NHE isoforms in mammals, and shares high similarity with the sequences within predicted transmembrane segments and an amiloride-binding domain. The expression of the gene was increased by salt stress. These results suggest that the product of the novel gene, OsNHX1, functions as a Na+/H+ exchanger, and plays important roles in salt tolerance of rice.
Department of Plant Physiology, National Institute of Agrobiological Resources, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602, Japan. fukuda@abr.affrc.go.jp
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Fukuda
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Nakamura
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Tanaka
D000595:Amino Acid Sequence; D001483:Base Sequence; D027682:Cation Transport Proteins; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000302:isolation & purification; D017343:Genes, Plant; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics*; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics; D020033:Protein Isoforms / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D017923:Sodium-Hydrogen Exchangers / Q000096:biosynthesis / Q000235:genetics*
D027682:Cation Transport Proteins; D018076:DNA, Complementary; C492183:NHX1 protein, S cerevisiae; D010940:Plant Proteins; D020033:Protein Isoforms; D029701:Saccharomyces cerevisiae Proteins; D017923:Sodium-Hydrogen Exchangers