Cloning and molecular characterization of glyceraldehyde-3-phosphate dehydrogenase gene from thermotolerant mushroom, Lentinus polychrous

This study describes the cloning and expression analysis of the heat shock protein gene, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), in thermotolerant mushroom Lentinus polychrous, one of the most widely cultivated commercial edible mushroom in Thailand. The complete GAPDH coding sequence contained 1,011 bp, encoding for a polypeptide of 337 amino acid residues with the calculated molecular mass of 36.2 kDa and pI of 5.64. Southern blot analysis revealed the presence of a single copy of the GAPDH gene in the L. polychrous genome. The putative amino acid sequence of the L. polychrous GAPDH-encoded protein shared significant sequence identity with other GAPDH proteins from basidiomycetes. Phylogenetic analysis clustered the L. polychrous GAPDH protein with other homobasidiomycetes. Expression analysis of the GAPDH gene by RT-PCR showed that this gene was highly induced not only by heat, but also by cold, ethanol and salt stresses. The GAPDH gene was expressed in both mycelia and fruiting bodies, suggesting that the GAPDH gene product is a heat shock protein which might be involved in the developmental phase of the L. polychrous.