Cloning of a Vacuolar H+-pyrophosphatase Gene from the Halophyte Suaeda corniculata whose Heterologous Overexpression Improves Salt, Saline-alkali and Drought Tolerance in Arabidopsis

Salt, saline-alkali conditions, and drought are major environmental factors limiting plant growth and productivity. The vacuolar H+-translocating inorganic pyrophosphatase (V-H+-PPase) is an electrogenic proton pump that translocates protons into vacuoles in plant cells. Expression of V-H+-PPase increases in plants under a number of abiotic stresses, and is thought to have an important role in adaptation to abiotic stress. In this work, we report the isolation and characterization of the gene, ScVP, encoding a vacuolar inorganic pyrophosphatase (V-H+-PPase) from the halophyte, Suaeda corniculata. Semi-quantitative reverse transcription-polymerase chain reaction analysis showed that ScVP was induced in roots, stems and leaves under treatment with salt, saline-alkali and drought. Compared with wild-type (WT) Arabidopsis, transgenic plants overexpressing ScVP accumulated more Na+ in leaves and roots, and showed increased tolerance to high salinity, saline-alkali and drought stresses. The germination percentage of transgenic Arabidopsis seeds was higher than that of WT seeds under the abiotic stresses. The root length of transgenic plants under salt stress was longer than that of WT plants. Furthermore, the rate of water loss during drought stress was higher in WT than in transgenic plants. Collectively, these results indicate that ScVP plays an important role in plant tolerance to salt, saline-alkali and drought stress.