Expression of the SOD gene from Trichoderma harzianum in Saccharomyces cerevisiae

Superoxide dismutases are metalloproteins which play a major role in defense against oxygen radical mediated toxicity in aerobic organisms.Such proteins are important endogeneity cytoprotection factor in volving defence.A 751-bp full-length cDNA sequence of an SOD gene was isolated from the Trichoderma harzianum.The full-length cDNA of the SOD gene consists of one 465-bp open reading frame nucleotide, which encodes a 15.7-kDa polypeptide consisting of 154 amino acid residues.Sequence analysis revealed that SOD gene has more than 72%-86% amino acid sequence homology with those of other fungi.The SOD gene was integrated into the genomic DNA of pYES2 by insertion into a single site for recombination, yielding the recombinant pYES2-SOD.SOD expressed by pYES2-SOD was induced by galactose.We test whether SOD could offer abiotic stress resistance when it was introduced into yeast cells.A transgenic yeast harboring T.harzianum SOD was generated under the control of a constitutively expressed GAL promoter.The results indicated that SOD yeast transfonnants had significantly higher resistance to salt and drought stress.