Screening for ergot alkaloid producers among microscopic fungi by means ofthe polymerase chain reaction

The potential of the polymerase chain reaction for the detection of ergot a lkaloid producers among microscopic fungi of the genera Penicillium and Cla viceps was evaluated. Twenty-three strains of various species of fungi with a previously studied capacity for alkaloid production were used. The inter nal fragment of the gene encoding 4-dimethylallyltryptophan synthase, the e nzyme catalyzing the first step in the biosynthesis of ergot alkaloids, was amplified using degenerate primers. This approach revealed an about 1.2-kb specific DNA fragment in micromycetes synthesizing ergot alkaloids with co mplete tetracyclic ergoline system. Microorganisms that produce alkaloids w ith modified C or D ergoline rings, as well as a-cyclopiazonic acid, did no t yield the PCR fragment of the expected size. This fragment was also not f ound in fungi incapable of ergot alkaloid production.