CULTURAL AND TOXIGENIC VARIABILITY IN FUSARIUM-ACUMINATUM

Twenty-five isolates of F. acuminatum from different sources and geographic origins were used for studying the cultural and toxigenic characteristics of the species. The isolates showed a large cultural variability, and the features ranged from slow-growing isolates with carmine-red pigmentation and relatively short 5-septate conidia to fast-growing yellow-brown isolates and long 5-septate conidia. The cultural differences corresponded to differences in production of secondary metabolites. On the basis of their metabolite production, the isolates were grouped into three categories: (a) enniatin B and/or moniliformin producers (up to 1000 and 2340 mg kg-', respectively); (b) T-2 toxin, HT-2 toxin and/or neosolaniol producers (up to 450, 40 and 20 mg kg-1, respectively); (c) no-toxin producers. The toxicity of the culture extract towards Artemia salina could usually be related to the occurrence of the above toxins.