Isolation and characterization of the gene encoding glyceraldehyde-3-phosphate dehydrogenase

A 1.2-kb full-length cDNA sequence of a glyceraldehyde-3-phosphate dehydrog enase (GPD) gene was isolated from the mushroom, Pleurotus sajor-caju. The full-length cDNA of the GPD gene consists of 1248 nucleotides, predicted to encode a 36-kDa polypeptide consisting of 335 amino acid residues. Sequenc e analysis revealed that the GPD gene has more than 72-78% amino acid seque nce homology with those of other Basidiomycetes. Expression of the GPD gene increased when P. sajor-caju was treated with various abiotic stresses, su ch as salt, cold, heat, and drought. There was an eightfold induction by dr ought treatment. Salt and cold stress induced four- and twofold induction o f GPD gene expression, respectively. There was also a fivefold induction by heat stress. The GPD gene exhibits different expression patterns under dif ferent stress conditions. It reached its maximum expression level within tw o hours under cold or heat treatment. The mRNA levels of this gene increase d proportionally to increasing treatment time under salt or dry conditions. Because the expression of GPD was significantly increased, we tested wheth er GPD could confer abiotic stress resistance when it was introduced into y east cells. For this, a transgenic yeast harboring P. sajor-caju GPD was ge nerated under the control of a constitutively expressed GAL promoter. The r esults from biofunctional analyses with GPD yeast transformants showed that GPD yeast transformants had significantly higher resistance to cold, salt, heat, and drought stresses, (C) 2000 Academic Press.