INCIDENCE, PHYLOGENY AND MYCOTOXIGENIC POTENTIALS OF FUNGI ISOLATED FROM RICE IN NIGER STATE, NIGERIAjfs_305 334..349

Abstract

The study reports on the natural occurrence of fungi in 21 samples of field (10), stored (6) and marketed (5) rice (Oryza sativa L.) collected from Niger State, Nigeria. Fungal isolates were primarily identified based on morphological characteristics, while representative isolates were characterized genetically.An evolutionary tree was constructed from the resulting sequences of the isolated fungi. The toxigenic potentials of some of the isolated fungi were also determined.A total of 357 fungal isolates of nine genera including Aspergillus, Fusarium, Sarocladium, Acremonium, Curvularia Botryosphaeria, Penicillium Alternaria and Ascomycota in decreasing order of predominance were identified. The most frequent fungal contaminants of the rice samples were A. flavus, A. fumigates, A. niger, A. parasiticus and F. proliferatum. All strains of A. flavus (aflatoxins B1 and B2), A. parasiticus (aflatoxins B1, B2, G1 and G2), A. ochraceus (ochratoxin A), F. proliferatum and F. verticillioides (fumonisins B1 and B2) tested, were excellent producers of their respective mycotoxins. Patulin was pro duced by A. terreus, whereas deoxynivalenol, zearalenone and T-2 toxin were pro duced by F. chlamydosporum and other Fusarium spp. The increased prevalence of toxigenic fungi in rice, a highly consumed food grain in Nigeria, poses serious health concerns to the general public.