Isolation and characterization of mitochondrial manganese superoxide dismutase (MnSOD) from Capsicum annuum L.

A cDNA clone for a mitochondrial manganese superoxide dismutase (MnSOD) was isolated and characterized from red pepper (Capsicum annuum L.). The clone consisted of 941 bp containing one open reading frame (ORF) of 687 bp, 34 bp/220 bp of 5'/3'-untranslated region. Amino acid sequence of the ORF showed the highest homology (86%) with that of Nicotiana plumbaginifolia. It encodes for a polypeptide of 228 amino acids with a molecular mass of 25.5 kDa and a pI value of 8.39. Genomic Southern hybridization suggested that more than one copy are present. Northern hybridization showed that the MnSOD transcript was more abundant in stems than in leaves and roots. When seedlings were treated with arsenate (0.1-10 mM), the MnSOD transcript level increased slightly at 0.1 mM and then dropped, while the Cu/ZnSOD transcript level increased at 1 mM, and also dropped at higher concentrations.