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 Tr/chodermaharzianum.The full-length cDNA of the SOD gene consists of one 465-bp open reading frame nu-cleotide,which encodes a 15.7-kDa polypeptide consisting of 154 amino acid residues.Sequence analy-sis revealed that SOD gene has more than 72%-86% amino acid sequence homology with those of otherfungi.The SOD gene was integrated into the genomic DNA of pYES2 by insertion into a single site for re-combination,yielding the recombinant pYES2-SOD.SOD expressed by pYES2-SOD was induced bygalactose.We test whether SOD could offer abiotic stress resistance when it was introduced into yeastcells.A transgenic yeast harboring T.harzianum SOD was generated under the control of a constitutivelyexpressed GAL promoter.The results indicated that SOD yeast transformants had significantly higher re-sistance to salt and drought stress.