Cloning and expression pattern of SsHKT1 encoding a putative cation transporter from halophyte Suaeda salsa.

Potassium is an essential element for plant, and high-affinity K+ uptake system plays a crucial role in potassium absorption and transportation. Here we report the isolation and characterization of a HKT1 homolog from C3 halophyte Suaeda salsa (L.) (SsHKT1), particularly under low K+ treatment. The SsHKT1 cDNA was 2033 nucleotides long including 1650 bp ORF for a 550 amino acids peptide and a predicted molecular mass of 63.0 kDa. The deduced amino acid sequence of SsHKT1 was 39-64% identical to other plant HKT-like sequences. A SsHKT1-specific antibody was prepared and reacted with a 63.0 kDa protein from S. salsa plasma membrane. Reverse transcriptase-PCR analysis showed that SsHKT1 was mainly expressed in leaf tissues and to a lesser extent, in root tissues. Amounts of SsHKT1 transcript were developmentally controlled and significantly up-regulated by K+ deprivation and NaCl treatment. The results suggested that SsHKT1 might play an important role in ion homeostasis and salt tolerance of S. salsa.