Lb1G04202, an Uncharacterized Protein from Recretohalophyte , Is Important in Salt Tolerance.

With global increases in saline soil, it has become increasingly important to decipher salt-tolerance mechanisms and identify strategies to improve salt tolerance in crops. Halophytes complete their life cycles in environments containing ≥200 mM NaCl; these remarkable plants provide a potential source of genes for improving crop salt tolerance. Recretohalophytes such as have salt glands that secrete Na on their leaf epidermis. Here, we identified , an uncharacterized gene with no conserved domains, from , which was highly expressed after NaCl treatment. We confirmed its expression in the salt gland by in situ hybridization, and then heterologously expressed in . The transgenic lines had a higher germination rate, greater cotyledon growth percentage, and longer roots than the wild type (WT) under NaCl treatments (50, 100 and 150 mM). At the seedling stage, the transgenic lines grew better than the WT and had lower Na and malonyldialdehyde accumulation, and higher K and proline contents. This corresponded with the high expression of the key proline biosynthesis genes and under NaCl treatment. Isotonic mannitol treatment showed that overexpression significantly relieved osmotic stress. Therefore, this novel gene provides a potential target for improving salt tolerance.