Abstract

In plants, superoxide dismutases are a family of metalloenzymes responsible for catalyzing the dismutation of superoxide radicals. A full-length cDNA encoding Cu/Zn-SOD gene (VsCu/Zn-SOD) was isolated from Vicia sativa using RT-PCR. The sequence analysis showed that the full-length cDNA of VsCu/Zn-SOD was 796 bp, including a 609bp ORF, a 56-bp 5′ UTR and 131-bp 3′ UTR. The ORF of VsCu/Zn-SOD encoded a protein of 202 amino acids with an isoelectric point of 5.94 and a predicted molecular weight of 20.55 kDa. The predicted protein was highly homologues to other Cu/Zn-SODs from legume plants and contained typical residues coordinating copper and zinc binding. The in silico analysis indicated that VsCu/Zn-SOD was targeted to the chloroplasts with a N-terminal chloroplast transit peptide indicating 47 residues. Phylogenetic analysis revealed that VsCu/Zn-SOD was evolutionary close to faba bean and pea Cu/Zn-SOD. The expression patterns of VsCu/Zn-SOD in different organs and under abiotic stresses were determined by quantitative RT-PCR. VsCu/Zn-SOD was differentially expressed in different organs of V. sativa and the highest expression levels were recorded in leaves followed by stems. Compared to control plants, VsCu/Zn-SOD was up-regulated in response to salt and drought stresses, suggesting a role in stress responses and tolerance.