Expression of the HSP24 gene from Trichoderma harzianum in Saccharomyces cerevisiae

Hsp24 is a small heat-shock protein (sHSP). Such proteins are important endogenous cytoprotection factors involved in defense. A 1116-bp full-length cDNA of the Hsp24, with a 645-bp open reading frame nucleotide encoding a 24-kDa polypeptide consisting of 214 amino acid residues, was isolated from Trichoderma harzianum. Sequence analysis revealed that Hsp24 gene has more than 42–58% amino acid sequence homology with those of other fungi. The Hsp24 gene was integrated into pYES2 by inserting into a single site for recombination, yielding the recombinant of pYES2/Hsp24. Hsp24 expressed by pYES2/Hsp24 was induced by galactose. We tested whether Hsp24 could confer abiotic stress resistance when it was introduced into yeast cells. A transgenic yeast harboring T. harzianum Hsp24 was generated under the control of a constitutively expressed GAL promoter. The results indicated that Hsp24 yeast transformants had significantly higher resistance to salt, drought and heat stresses.