Molecular cloning and functional characterization of a Na+/H+ antiporter gene from halophyte spartina anglica

Abstract

Na+/H+ antiporters have been suggested to play important roles in salt tolerance in plants. English cordgrass (Spartina anglica) is a gramineous halophyte with very strong salt tolerance. It possesses salt glands in its stems and leaves, through which excess salt can be excreted. In this study, a vacuolar Na+/H+ antiporter homologous gene (temporarily named SaNHX1) was isolated from Spartina anglica by RT-PCR and rapid amplification of cDNA ends (RACE). Southern blot analysis suggested that there might be 2 or 3 copies of the vacuolar Na+/H+ antiporter genes in the English cordgrass genome. Northern blot analysis showed that the expression of vacuolar Na+/H+ antiporter genes in English cordgrass is induced by salt stress. Overexpression of SaNHX1 driven by constitutive promoter Ubi-1 in rice significantly enhanced the salt tolerance of transgenic plants, validating the function of SaNHX1 and suggesting its value for the genetic improvement of salt tolerance in plants. © TÜBİTAK.