Abstract

Pleurotus spp. are well known and important cultivated mushrooms. However, the pyrGgene in Pleurotus spp., which is used as a bio-safe selective marker in transformation systems, has not yet been characterized. In the present study, nested degenerated PCR was used to clone conserved fragments of the pyrG gene from Pleurotus ostreatus andPleurotus eryngii. Chromosome walking technology was then used to obtain the full-length DNA sequence of pyrG. Finally, reverse transcriptase (RT) PCR was used to obtain thepyrG cDNA sequence. The cDNA sequence of P. ostreatus and P. eryngii were all 813 bp in length and encoded 246 amino acids. Comparison of the DNA sequences with cDNA sequences of both P. ostreatus and P. eryngii indicated that pyrG genes of these two strains consisted of two introns and their deduced amino acid sequence showed 93.09% similarity. Moreover, the 5’-flanking region of these two genes was analyzed.

Key words: Pleurotus ostreatus, Pleurotus eryngii, pyrG, nested PCR, chromosome walking.