Molecular Cloning and Characterization of a Vacuolar H+-pyrophos-phatase Gene, SsVP, from the Halophyte Suaeda salsa and its Overexpression Increases Salt and Drought Tolerance of Arabidopsis

The chenopodiaceae Suaeda salsa L. is a leaf succulent euhalophyte. Shoots of the S. salsa are larger and more succulent when grown in highly saline environments. This increased growth and water uptake has been correlated with a large and specific cellular accumulation of sodium. S. salsa does not have salt glands or salt bladders on its leaves. Thus, this plant must compartmentalize the toxic Na⁺ in the vacuoles. The ability to compartmentalize sodium may result from a stimulation of the proton pumps that provide the driving force for increased sodium transport into the vacuole. In this work, we isolated the cDNA of the vacuolar membrane proton-translocating inorganic pyrophosphatase (H⁺-PPase) from S. salsa. The SsVP cDNA contains an uninterrupted open reading frame of 2292 bp, coding for a polypeptide of 764 amino acids. Northern blotting analysis showed that SsVP was induced in salinity treated leaves. The activities of both the V-ATPase and the V-PPase in Arabidopsis overexpressing SsVP-2 is higher markedly than in wild-type plant under 200 mM NaCl and drought stresses. The Overexpression of SsVP can increase salt and drought tolerance of transgenic Arabidopsis. Electronic supplementary material Electronic supplementary material is available for this article at and accessible for authorised users. Shanli Guo, Haibo Yib: These authors contributed equally to this work