Zearalenone production in Fusarium culmorum after transformation with DNA of F. graminearum

Total DNA from a cycloheximide‐resistant mutant of Fusarium graminearum producing zearalenone was incubated with the protoplasts of a non‐zearalenone‐producing cycloheximide‐susceptible isolate of F. culmorum. The regenerated protoplasts were inoculated on a 5‐mM cycloheximide medium. The cultures which developed were examined for zearalenone production. Sixty‐five cycloheximide‐resistant isolates, including two isolates producing zearalenone, were obtained from approximately 3.6 × 104 viable F. culmorum protoplasts. Similar incubations with homologous F. culmorum DNA and non‐fungal DNA did not elicit zearalenone production. The results suggest the transformation of F. culmorum by the genetic factors responsible for cycloheximide resistance and zearalenone production from F. graminearum. The epidemiological and taxonomic significance of these observations is discussed.