Composition of Mycoflora and Aflatoxins in Lupine Seeds from the Sudan

Abstract

Thirteen seed samples of lupines (Lupinus termis Forrsk.) were evaluated for their phytosanitary status by incubation on potato-dextrose agar (PDA) and moist sterile filter papers (blotter method) at 28±2ºC. The seeds were also assayed for the presence of aflatoxins and toxigenic fungi. Forty-seven species and 10 varieties in 14 genera of fungi were recovered. Among these, 45 species and 10 varieties were new to lupine seeds, and 5 species and 2 varieties were new to the mycoflora of the Sudan. The genus Aspergillus (10 species, 8 varieties) was the most common, followed by Rhizopus (1 species), Fusarium (6 species) and Alternaria (5 species), while the remaining genera (Chaetomium, Cladosporium, Curvularia, Drechslera, Penicillium, Phoma, Emericella, Mucor, Sclerotium, Ulocladium) displayed lower levels of contamination. Of possible pathogens on lupine plants, Alternaria (5 species) (stem lesion) and F. oxysporum (root rot) were recovered from the seeds. Thin-layer chromatographic analysis of chloroform extracts of the 13 seed samples revealed that two samples contained very low concentrations of aflatoxins B1 and B2 (4.5-6.5 µg/kg).