Transformation of the edible fungi, Pleurotus ostreatus and Volvariella volvacea

A transformation system is described for the edible mushrooms Pleurotus ostreatus and Volvariella volvacea. The system developed is based on a positive selection strategy using the trp3(iar) gene from Coprinus cinereus, which confers resistance to the antimetabolite 5-fluoroindole. Transformation frequencies were low in both species. Southern blot analysis confirmed the integration of transforming DNA into the genome of transformants and indicated the presence of tandemly duplicated copies of the plasmid in some of these transformants. The system has potential for introducing beneficial traits such as enhanced substrate bioconversion and faster sporophore development.