biologia plantarum

Biologia plantarum 60:113-122, 2016 | DOI: 10.1007/s10535-015-0560-8

Isolation and characterization of a tonoplast Na⁺/H⁺ antiporter from the halophyte Nitraria sibirica

L. Wang¹, Y. K. Ma¹, N. N. Li¹, W. B. Zhang¹, H. P. Mao¹, X. F. Lin^1,*

¹ College of Life Sciences, Inner Mongolia University, Hohhot, P.R. China

Na⁺/H⁺ exchanger (NHX)-mediated Na⁺ and H⁺ antiport is an important mechanism for salt tolerance in plants. In this study, an Na⁺/H⁺ antiporter gene, referred to as NsNHX1, was isolated from the halophyte Nitraria sibirica Pall. using degenerate polymerase chain reaction (PCR) and rapid amplification of cDNA ends (RACE). The resulting 2 182 bp NsNHX1 cDNA contained a 1 635 bp open reading frame (ORF) that encoded 544 amino acids and showed striking sequence similarity to tonoplast-localized NHXs from other plants. Subcellular localization analysis confirmed NsNHX1 to be a tonoplast-localized protein. Cis-elements described as being responsive to biotic and abiotic stresses were present in the NsNHX1 promoter region, and reverse transcription (RT)-PCR analysis confirmed that NsNHX1 expression was induced by exogenous abscisic acid (ABA), cold, and NaCl. Transcription of NsNHX1 increased sharply 3 h after treatment with 200 mM NaCl revealing that NsNHX1 responded rapidly to the salt stress. Overexpression of NsNHX1 enhanced salt tolerance in transgenic Arabidopsis thalliana L. suggesting that NsNHX1-mediated Na⁺ compartmentalization played an important role in enhancing plant salt tolerance.

Keywords: abscisic acid; cold stress; gene expression; RACE; salt-tolerance; transgenic Arabidopsis

Subjects: tonoplast; halophytes; antiporters; sodium; abscisic acid; gene expression; RACE; salt tolerance; transgenic plants; phylogenetic tree

Received: March 22, 2013; Revised: March 17, 2015; Accepted: May 4, 2015; Published: January 1, 2016  Show citation