Mycotoxin production by Fusarium species isolated from bananas

Abstract

The ability of Fusarium species isolated from bananas to produce mycotoxins was studied with 66 isolates of the following species: F. semitectum var. majus (8 isolates), F. camptoceras (3 isolates), a Fusarium sp. (3 isolates), F. moniliforme (16 isolates), F. proliferatum (9 isolates), F. subglutinans (3 isolates), F. solani (3 isolates). F. oxysporum (5 isolates), F. graminearum (7 isolates), F. dimerum (3 isolates), F. acuminatum (3 isolates), and F. equiseti (3 isolates). All isolates were cultured on autoclaved corn grains. Their toxicity to Anemia salina L. larvae was examined. Some of the toxic effects observed arose from the production of known mycotoxins that were determined by thin-layer chromatography, gas chromatography, or high-performance liquid chromatography. All F. camptoceras and Fusarium sp. isolates proved toxic to A. salina larvae; however, no specific toxic metabolites could be identified. This was also the case with eight isolates of F. moniliforme and three of F. proliferatum. The following mycotoxins were encountered in the corn culture extracts: fumonisin B1 (40 to 2,900 μg/g), fumonisin B2 (150 to 320 μg/g), moniliformin (10 to 1,670 μg/g), zearalenone (5 to 470 μg/g), α-zearalenol (5 to 10 μg/g), deoxynivalenol (8 to 35 μg/g), 3-acetyldeoxynivalenol (5 to 10 μg/g), neosulaniol (50 to 180 μg/g), and T-2 tetraol (5 to 15 μg/g). Based on the results, additional compounds produced by the fungal isolates may play prominent roles in the toxic effects on larvae observed. This is the first reported study on the mycotoxin-producing abilities of Fusarium species that contaminate bananas.