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AaNhaD,a gene isolated from the soda lake alkaliphile Alkalimonas amylolytica,encodes a Na+/H+ antiporter crucial for the bacterium’s resistance to salt/alkali stresses.However,it remains unknown whether this type of bacterial gene may be able to increase the tolerance of flowering plants to salt/alkali stresses.To investigate the use of extremophile genetic resources in higher plants,transgenic tobacco BY-2 cells and plants harboring AaNhaD were generated and their stress tolerance was evaluated.Ectopic expression of AaNhaD enhanced the salt tolerance of the transgenic BY-2 cells in a pH-dependent manner.Compared to wild-type controls,the transgenic cells exhibited increased Na+concentrations and pH levels in the vacuoles.Subcellular localization analysis indicated that AaNhaD-GFP fusion proteins were primarily localized in the tonoplasts.Similar to the transgenic BY-2 cells,AaNhaD-overexpressing tobacco plants displayed enhanced stress tolerance when grown in saline-alkali soil.These results indicate that AaNhaD functions as a pH-dependent tonoplast Na+/H+antiporter in plant cells,thus presenting a new avenue for the genetic improvement of salinity/alkalinity tolerance.
AaNhaD, a gene isolated from the soda lake alkaliphile Alkalimonas amylolytica, encodes a Na + / H + antiporter crucial for the bacterium’s resistance to salt / alkali stresses. Yet, it remains unknown whether this type of bacterial gene may be able to increase the tolerance of flowering plants to salt / alkali stress.To investigate the use of extremophile genetic resources in higher plants, transgenic tobacco BY-2 cells and plants harboring AaNhaD were generated and their stress tolerance was evaluated. Ectopic expression of AaNhaD enhanced the salt tolerance of the transgenic BY -2 cells in a pH-dependent manner .Compared to wild-type controls, the transgenic cellages increased increased Na + concentrations and pH levels in the vacuoles. Subcellular localization analysis indicated that AaNhaD-GFP fusion proteins were primarily in the tonoplasts. to the transgenic BY-2 cells, AaNhaD-overexpressing tobacco plants displayed enhanced stress tolerance when grown in saline-alkali soil. results indicate that AaNhaD functions as a pH-dependent tonoplast Na + / H + antiporter in plant cells, thus presenting a new avenue for the genetic improvement of salinity / alkalinity tolerance.