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 pr edicted 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 amin o acid identity (88%), however, was shown with Coprinus CoLIM15, a DMC1 hom olog recently found in Coprinus cinereus. The exact matching of sizes and p ositions of most introns in both basidiomycete genes underlines the close r elationship between these DMC1 orthologs. The RecA homolog DMC1 from yeast and its orthologs from other species have been reported to be meiosis speci fic 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, th e gene is not expressed in the lamellae/basidiospore fraction of a nonsporu lating mutant of P. ostreatus. Since one of the major problems in cultivati ng the oyster mushroom is the abundant sporulation that causes allergic rea ctions in man, PoDMC1 could be an important target gene in constructing spo reless Pleurotus strains. (C) 2001 Academic Press.