Identification MdeSOS1 in Magnolia denudata and its function in response to salt stress

In this study, annual Magnolia denudata seedlings were treated with a 200 mmol L-1 NaCl solution. Na+ content in its stems increased by more than about 24 times after 72 h and K+ content in leaves basically maintained in a steady state. MdeSOS1, isolated from M. denudata, comprised a 3453-bp ORF and included 12 transmembrane structures within its N terminal and a hydrophilic tail in its C-terminal. Its protein shared the identity of 68.3% and 62.7% at the peptide level with the homologue PeSOS1 and AtSOS1 respectively. The MdeSOS1 was significantly induced to up-regulation in various tissues exposed to salt stress and improved the salt tolerance of Arabidopsis. Our results also revealed that the MdeSOS1-GFP fusion protein was located on the plasma membrane and MdeSOS1 encoded a salt-inducible plasma membrane Na+/H+ antiporter, which provides a reference to improve the salt tolerance of Magnolia species by transgenic approaches.