Production of Fumonisin B Analogues and Related Compounds by Fusarium globosum, a Newly Described Species from Corn
Fusarium globosum Rheeder, Marasas et Nelson is a recently described species originally isolated from corn kernels harvested in the Transkei region of South Africa. On the basis of morphological criteria, F. globosum is closely related to other common fungal contaminants of corn, viz. F. moniliforme, F. proliferatum, and F. subglutinans, and accordingly it has been classified in the section Liseola. Species within the section Liseola have been reported to produce either the fumonisin B or moniliformin (MON) mycotoxins and, in some cases both. Seventeen isolates of F. globosum, cultured on corn, were screened for the production of fumonisins B1 (FB1), B2 (FB2), B3 (FB3), and MON. All isolates produced FB1 (range 5-325 μg/g), while 15 of 17 also produced FB2 (range 1-4 μg/g). For 14 of 17 isolates, the levels of FB3 produced (range 4-24 μg/g) exceeded those of the corresponding FB2 concentrations. None of the isolates produced detectable levels of MON (<1 μg/g). In addition, several isolates of F. globosum also produced two additional fumonisin-like compounds, the mass spectral evidence of which suggests that they may be isomers of FB1 and FB2 or FB3, respectively.