Transformation of the fungal forest pathogen Dothistroma pini to hygromycin resistance

The forest pathogen Dothistroma pini, which produces the polyketide toxin, dothistromin, was transformed with the pAN7-1 plasmid containing the Escherichia coli hygromycin B phosphotransferase gene (hph). The frequency of hygromycin resistant transformants was 9–48 μg−1 DNA. Southern blot analysis indicated that a single copy of the vector DNA had integrated into the genome in at least six of the eight transformants tested and that the site of integration was different in each case. All transformants analysed were mitotically stable through several subcultures without selective pressure.