PRODUCTION OF TYPE-A TRICHOTHECENES AND ENNIATIN-B BY FUSARIUM-SAMBUCINUM FUCKEL SENSU-LATO

Twenty-nine Fusarium isolates, representing three new taxa originated by Nirenberg from F. sambucinum Fuckel sensu lato, namely: F. sambucinum Fuckel sensu stricto, F. venenotum Nirenb., and F. torulosum (Perk. and Curt.) Nirenb., were tested for in vitro production of toxic secondary metabolites on autoclaved corn kernels. F. sambucinum sensu stricto was able to produce type A trichothecenes and enniatin B (EB). In particular, amongst the 14 isolates tested, 5 produced only diacetoxyscirpenol (DAS) (up to 700 mu g/g); 1 produced only neosolaniol (NEOS) (250 mu g/g); 2 produced T-2 toxin (T-2) + NEOS (up to 175 and 150 mu g/g, respectively); 1 produced NEOS + DAS (300 and 100 mu g/g, respectively); and 5 produced DAS + EB (up to 500 and 140 mu g/g, respectively). All six isolates of F. venenotum were able to produce only DAS (up to 100 mu g/g). F. torulosum produced no trichothecenes, but four out of nine tested isolates were able to produce EP (up to 140 mu g/g). Zearalenones and type B trichothecenes were not found. The toxicity of the culture extracts towards Artemia salina L. was correlated in general with the occurrence of the above toxins, except for some F. torulosum strains. However, the lack of correlation between the amounts of toxins recovered and toxic activity observed in the Geotrichum candidum Link ex Pers. and A. salina assays suggested the presence of unknown toxic compounds.