Overexpression of AtNHX1, a Vacuolar Na+/H+ Antiporter from Arabidopsis thalina, in Petunia hybrida Enhances Salt and Drought Tolerance

Abstract

Plant Na+/H+ antiporter plays a critical role in plant salt tolerance. In this study, AtNHX1, a vacuolar Na+/H+ antiporter from Arabidopsis thalina, was introduced into Petunia hybrida using Agrobacterium-mediated methods. Polymerase chain reaction (PCR) and DNA gel blot analysis confirmed that AtNHX1 was successfully integrated into the P. hybrida genomes. Reverse transcription (RT)-PCR analysis indicated that AtNHX1 expressed highly in transgenic plants. It was found that the 35S::AtNHX1 transgenic P. hybrida plants showed much more resistant to high concentrations of NaCl and to water deprivation than the isogenic wild-type (WT) Petunia plants. The transgenic plants accumulated more Na+, K+, and proline in their leaf tissue than that of the WT Petunia plants and maintained high water contents and high ratio of K+/Na+. These results demonstrated that overexpression of the vacuolar Na+/H+ antiporter conferred both salt tolerance and drought tolerance to the transgenic Petunia plants.