title: A Low-Affinity K+ Transporter AlHKT2;1 from Recretohalophyte Aeluropus lagopoides Confers Salt Tolerance in Yeast.
abstract: The high-affinity potassium transporters (HKT) are highly important for stress tolerance in plants as they uniquely maintain K(+)/Na(+) ratio for their survival and growth. In this study a novel HKT gene AlHKT2;1 was isolated and characterized from salt secreting halophyte, Aeluropus lagopoides. The AlHKT2;1 cDNA comprised of an open reading frame of 1,581 bp, encoding a protein of 526 amino acid residues. It belongs to class II HKTs and showed high homology with other HKT genes. Functional characterization of AlHKT2;1 in both K(+) uptake-deficient (WΔ6) and Na(+)-sensitive yeast mutants (G19) showed the characteristic feature of low-affinity K(+) transporter supporting the growth at >1 mM KCl concentration. The transformed yeast cells showed high sensitivity to NaCl; however, the addition of KCl along with NaCl support the growth of AlHKT2;1 expressing mutant. Ion content analysis of yeast cells with AlHKT2;1 grown in high NaCl medium supplemented with KCl revealed that salt tolerance was correlated with accumulation of K(+) during salt stress. These results suggest that AlHKT2;1 plays an important role in the K(+) uptake during salt stress and in maintaining a high K(+)/Na(+) ratio in the cytosol.
authors.affiliation: Discipline of Wasteland Research, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific and Industrial Research (CSIR), Gijubhai Badheka Marg, Bhavnagar, 364 002, Gujarat, India.
authors.forename: Payal
authors.initials: P
authors.lastname: Sanadhya
authors.forename: Parinita
authors.initials: P
authors.lastname: Agarwal
authors.forename: Jackson
authors.initials: J
authors.lastname: Khedia
authors.forename: Pradeep K
authors.initials: PK
authors.lastname: Agarwal
mesh_terms: D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D010802:Phylogeny; D006109:Poaceae / Q000235:genetics*; D011188:Potassium / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D012965:Sodium Chloride
chemical_list: D002352:Carrier Proteins; D012965:Sodium Chloride; D011188:Potassium