Isolation, characterization, and expression patterns of a DMC1 homolog from the basidiomycete Pleurotus ostreatus.

Here we describe the isolation of a Pleurotus ostreatus gene PoDMC1. The predicted amino acid sequence of the oyster mushroom gene is 62% identical to the yeast DMC1 and 60% identical to human DMC1. The highest degree of amino acid identity (88%), however, was shown with Coprinus CoLIM15, a DMC1 homolog recently found in Coprinus cinereus. The exact matching of sizes and positions of most introns in both basidiomycete genes underlines the close relationship between these DMC1 orthologs. The RecA homolog DMC1 from yeast and its orthologs from other species have been reported to be meiosis specific and essential for sporulation. Here we show that PoDMC1 is exclusively expressed in the lamellae/basidiospore fraction of fruit bodies and not in somatic cells of fruiting bodies or in vegetative mycelium. Furthermore, the gene is not expressed in the lamellae/basidiospore fraction of a nonsporulating mutant of P. ostreatus. Since one of the major problems in cultivating the oyster mushroom is the abundant sporulation that causes allergic reactions in man, PoDMC1 could be an important target gene in constructing sporeless Pleurotus strains. Copyright 2001 Academic Press.