Salt overly sensitive 1(SOS1) gene, encoding a Na+/H+antiport protein, plays an important role in biological processes of plants against salt stress. Using a SOS1 mRNA sequence from Triticum aestivum (KJ563230) as the probe, the homologous ESTs of sugarcanewere obtainedfrom NCBI database. A sugarcane cDNA sequence of SOS1 gene was cloned by in silicocloning combined with RT-PCR,and named as ScSOS1 (GenBank accession number: KT003285). The bioinformatics analysis showed that ScSOS1 has a length of 1403bp witha complete open reading frame (ORF, 107 to 1423 bp), encoding a 423 amino acid residues of sugarcane SOS1 protein with an estimated molecular weight of 47.6 kD and a calculated isoelectric point (pI) of 9.12. The protein of ScSOS1 belongs to a conserved CAP-ED superfamily. Yet the ScSOS1 protein has no signal peptide and belongs to hydrophilic protein with the main function forintermediary metabolism. The mainly secondary structure element of ScSOS1 protein is random coil. Real-time quantitative PCR (RT-qPCR) analysis revealed that ScSOS1was tissue-specificallyexpressed in leaf sheath, bark, pulp, bud and root of sugarcane,with the highest expression in leaf sheath and the lowest in root. Besides,the expression of ScSOS1gene could beregulatedby the treatments of NaCl, PEG, ABA, SA,and MeJA,and up-regulatedby the stresses of NaCland PEG, with the highest inducible expression levels of1.5 times and 4.0 times ashigh as those of control at 24 hours, respectively. This paper suggested that ScSOS1involves in sugarcane tolerance salt and osmotic stresses. It can set up a basis for the elucidation of sugarcane salt resistancemechanism.
