Arabidopsis Qc-SNARE gene AtSFT12 is involved in salt and osmotic stress responses and Na accumulation in vacuoles.

Key message: AtSFT12, an Arabidopsis Qc-SNARE protein, is localized to Golgi organelles and is involved in salt and osmotic stress responses via accumulation of Na in vacuoles. Abstract: To reduce the detrimental effects of environmental stresses, plants have evolved many defense mechanisms. Here, we identified an Arabidopsis Qc-SNARE gene, AtSFT12, involved in salt and osmotic stress responses using an activation-tagging method. Both activation-tagged plants and overexpressing transgenic plants (OXs) of the AtSFT12 gene were tolerant to high concentrations of NaCl, LiCl, and mannitol, whereas loss-of-function mutants were sensitive to NaCl, LiCl, and mannitol. AtSFT12 transcription increased under NaCl, ABA, cold, and mannitol stresses but not MV treatment. GFP-fusion AtSFT12 protein was juxtaposed with Golgi marker, implying that its function is associated with Golgi-mediated transport. Quantitative measurement of Na using induced coupled plasma atomic emission spectroscopy revealed that AtSFT12 OXs accumulated significantly more Na than WT plants. In addition, Na-dependent fluorescence analysis of Sodium Green showed comparatively higher Na accumulation in vacuoles of AtSFT12 OX cells than in those of WT plant cells after salt treatments. Taken together, our findings suggest that AtSTF12, a Golgi Qc-SNARE protein, plays an important role in salt and osmotic stress responses and functions in the salt stress response via sequestration of Na in vacuoles. [ABSTRACT FROM AUTHOR]