Over-expression of a subunit E1 of a vacuolar H+-ATPase gene (Lm VHA-E1) cloned from the halophyte Lobularia maritima improves the tolerance of Arabidopsis thaliana to salt and osmotic stresses

•Lobularia maritima as a source of transgenes to improve the tolerance of Arabidopsis to salt and osmotic stresses.•Vacuolar H+-ATPase of L. maritima (Lm VHA-E1) is responsive to many stress factors.•The tolerance of Arabdopsis was significantly improved after Lm VHA-E1 gene transfer.

In order to understand the molecular basis of vacuolar H+-ATPase subunits and reveal their possible role in salt and drought tolerance in plant species, a vacuolar H+-ATPase subunit E1 gene (LmVHA-E1) was isolated from the halophyte Lobularia maritima and over-expressed in the glycophyte Arabidopsis thaliana. Q-RT-PCR demonstrated that the expression of this gene was induced in L. maritima in response to salt stress and PEG-induced osmotic stress. The overexpression of LmVHA-E1 in Arabidopsis thaliana conferred high salt and drought tolerance to transgenic plants. Transgenic Arabidopsis plants showed higher seedling survival rates and better antioxidant activities under salt and drought stress. The analysis of ion content and osmotic potentials indicated that under high salinity the transgenic plants compartmentalized more Na+ and showed enhanced osmotic adjustment in the leaves compared with wild-type plants. Accordingly, the higher levels of expression of different stress related genes such as AtNHX1 AtP5CS, AtCAT, AtSOD, AtPOD and AtLEA, indicated higher levels of activities in sodium sequestration into vacuoles, in osmotic regulation and in ROS scavenging of transgenic plants.