The phylogenetic tree was constructed using MEGA ver. 5.0. The following protein sequences were used to construct of the phylogenetic tree: Arabidopsis thaliana AtSOS1 (AF256224) and AtNHX1 (AF510074), Chrysanthemum crassum CcSOS1 (AB439132), Halostachys caspica HcNHX1 (GU188850), Helianthus tuberosus HtSOS1 (KC410809), Kosteletzkya virginica KvSOS1 (KJ577576), Limonium gmelinii LgSOS1 (EU780458), Oryza sativa OsSOS1 (AY785147) and OsNHX1 (AB021878), Populus euphratica PeSOS1 (DQ517530) and PeNHX1 (FJ866610), Pennisetum glaucum PgNHX1 (DQ071264), Salicornia brachiata SbSOS1 (EU879059), Salicornia europaea SeNHX1 (AY131235), Suaeda japonica SjSOS1 (AB198179), Suaeda salsa SsSOS1 (KF914414), Theobroma cacao TcSOS1 (XM_007045345) and TcNHX1 (XM_007030729), Thellungiella halophila ThSOS1 (EF207775), Vitis vinifera VvSOS1 (CAO42437) and Zoysia japonica ZjNHX1 (EU333827).