Transformation of the cultivated mushroom Agaricus bisporus (Lange) using T-DNA from Agrobacterium tumefaciens.

Agrobacterium tumefaciens is known to transfer parts of its tumor-inducing plasmid, the T-DNA, to plants, yeasts and filamentous fungi. We have used this system to transform germinating basidiospores and vegetative mycelium of a commercial strain of the cultivated basidiomycete Agaricus bisporus. Analysis of transformants shows that the T-DNA integrates at random sites into the host genome and that the selection marker is stable during mitosis and meiosis. The Agrobacterium system allows the transformation of both homokaryons and heterokaryons of A. bisporus. Also, both karyotypes of an heterokaryon can be transformed simultaneously. Furthermore, this is the first report on the transformation of vegetative mycelium of a commercial strain of A. bisporus.