Sequence and Expression Analysis of Cytoplasmic Copper/zinc Superoxide Dismutase Gene in Rice

The 698 bp cytoplasmic copper/zinc-superoxide dismutase gene (OsCu/Zn-SOD) was cloned by RT-PCR from young panicles of rice Cpslo17, a wide-compatible rice cultivar (Oryza sativa). DNA sequence analysis indicated that the gene consisted of a full-open reading frame and encoded a protein of 152 amino acid residues. The nucleatide sequence of OsCu/Zn-SOD shares 88% identity to maize Cu/Zn-SOD. No signal peptide was predicted by TargetP and ChloroP. Further analysis of encoding segment of OsCu/Zn-SOD revealed that it contained 8 exons and 7 introns. The putative three-dimensional structure of OsCu/Zn-SOD was predicted by the Swiss-Model server and Cu2+ and Zn2+ binding sites of OsCu/Zn-SOD were analyzed. RT-PCR results showed differential expression of OsCu/Zn-SOD in leaves of both japnica and indica rice. OsCu/Zn-SOD was expressed highly in panicles during young ear and the flowering stages or in immature seeds, however less in leaves and faintly in callus.