Abstract:Members of the activity of bc1 complex (Abc1) family are protein kinases that are functionally diverse proteins with multiple roles in the regulation of plant growth and development and abiotic stress tolerance. According to the amino acid sequence of AtOSA1 and the transcriptome data of Nicotiana tabacum, a Abc1 like gene was isolated and designated as NtOSA1, as for the high identity with the AtOSA1 (Arabidopsis thaliana oxidative stressrelated Abc1like protein). The open reading frame (ORF) of the NtOSA1 gene is 2 283 bp which encoded a deduced protein including 760 amino acid residues. The protein sequence of NtOSA1 possesses a conserved ABC1 domain, one kinase domain, one chloroplast localization signal peptide and two transmembrane spans. The relative expression of NtOSA1 was determined by quantitative realtime PCR (qRTPCR). The results showed that NtOSA1 gene was expressed particularly in leaves, but also in flowers. After treatment of H2O2 and NaCl for 6 h, the expression of NtOSA1 increased to the maximum, which was 1.95 and 2.69 folds of the control, respectively. When fused to green fluorescent protein (GFP), NtOSA1 localized to the chloroplast in tobacco protoplasts, which was consistent with the prediction results of the software TargetP 1.1 Server. These results suggested that NtOSA1 may be involved in response to oxidative and salt stress in tobacco.