Efficient transformation of filamentous fungus Pleurotus ostreatus using single-strand carrier DNA

The effects of carrier DNAs on the transformation of the basidiomycete Pleu rotus ostreatus were analyzed. When lambda phage DNA was added to a transfo rmation mixture containing protoplasts and Cbx(R) vector plasmid, an increa sed number of drug-resistant transformants was observed on a screening plat e containing 2 mug carboxin/ml. The highest efficiency (about 200 transform ants/mug Vector plasmid) was obtained by the addition of heat-denatured lam bda DNA, which gave yields approximately 50-fold higher than the control ex periment without a carrier DNA. To our knowledge, this is the first report on enhancement in transformation efficiency of fungal protoplasts by single strand carrier DNA.