Cloning and characterization of a differentially expressed mitochondrial manganese superoxide dismutase gene from Pleurotus ostreatus

Manganese-containing superoxide dismutase (Mn-SOD) is one of the most important superoxide dismutases found in many eukaryotes and bacteria. In this study, the full-length cDNA of mitochondrial manganese superoxide dismutase from Pleurotus ostreatus (PoMn-SOD) was obtained. It contained 776 nucleotides with an open reading frame (ORF) of 663 bp, encoding 220 amino acid residues. The deduced amino acid sequence showed high identity with the sequences of other basidiomycetous Mn-SODs from Trametes versicolor (71 %) to Laccaria bicolor (77 %). Quantitative real-time PCR (RT-PCR) analysis revealed that PoMn-SOD gene transcripts were abundant in the stage of young fruit bodies and mature fruit bodies. The up-regulation of the PoMn-SOD gene suggested that it was developmental regulated and could play an important role in antagonizing environmental stresses. In addition, another isoform of Mn-SOD was detected by a non-denaturing polyacrylamide gel electrophoresis (PAGE) approach and the highest total Mn-SOD activity (203.9 U/mg) was observed in the stage of mature fruit bodies. These data could provide important reference for functional study of the PoMn-SOD gene and may benefit biotechnological production of Mn-SOD in the future.