Transformation of Penicillium chysogenum with selection for increased resistance to benomyl

Incubation of protoplasts of Penicillium chrysogenum with the plasmid pBT-3 permitted selection of transformants on the basis of increased resistance to the anti-fungal agent benomyl. Transformants were obtained at a frequency of 1–2 per μg of DNA. Southern analysis revealed that transformation had occured by integration of vector sequences into the host genome.