, a Vacuolar-Localized Na/H Antiporter, Positively Regulates Salt Response in Upland Cotton.

Vacuolar sodium/proton (Na/H) antiporters (NHXs) can stabilize ion contents to improve the salt tolerance of plants. Here, was cloned and characterized from upland cotton (). Phylogenetic and sequence analyses showed that belongs to the vacuolar-type NHXs. The GhNHX3D-enhanced green fluorescent protein (eGFP) fusion protein localized on the vacuolar membrane when transiently expressed in protoplasts. The quantitative real-time PCR (qRT-PCR) analysis showed that was induced rapidly in response to salt stress in cotton leaves, and its transcript levels increased with the aggravation of salt stress. The introduction of into the salt-sensitive yeast mutant ATX3 improved its salt tolerance. Furthermore, silencing of in cotton plants by virus-induced gene silencing (VIGS) increased the Na levels in the leaves, stems, and roots and decreased the K content in the roots, leading to greater salt sensitivity. Our results indicate that is a member of the vacuolar NHX family and can confer salt tolerance by adjusting the steady-state balance of cellular Na and K ions.