Poster: Biology & Disease Mgmt: Postharvest Pathology & Mycotoxins
Diversity of aflatoxin-producing fungi in non-agriculture soils of Zambia
P. KACHAPULULULA (1), J. AKELLO (2), R. BANDYOPADHYAY (3), P. COTTY (4) (1) UNIVERSITY OF ARIZONA, U.S.A.; (2) INTERNATIONAL INSTITUTE OF TROPICAL AGRICULTURE (IITA), Zambia; (3) INTERNATIONAL INSTITUTE OF TROPICAL AGRICULTURE (IITA), Nigeria; (4) USDA-AR
Aflatoxins are cancer-causing, immunosuppressive toxins that contaminate maize and groundnut, important staples in Zambia. Aspergillus flavus, A. parasiticus and two unnamed taxa are frequently implicated as causal agents of contamination in Africa. Most of Zambia’s arable land is uncultivated. Aspergillus communities in crops may have originated in uncultivated regions and soils in these areas may serve as reservoirs of toxin-producers. Understanding fungal communities in cultivated and uncultivated areas may facilitate aflatoxin management. Soils from fields cropped to maize and groundnut (161) and from uncultivated land (53) were assayed for Aspergillus section Flavi from 2012 to 2016. Communities in both wild and cultivated soils were dominated by A. parasiticus (90% and 50%, respectively) and the A. flavus L morphotype (5% and 31%, respectively). Phylogenetic analyses with partial gene sequences for nitrate reductase (niaD, 1.8 kb) and the aflatoxin pathway transcription factor (aflR, 2.1 kb) resolved 20 A. parasiticus isolates from cultivated soils into 4 well supported lineages. Relationships among the 4 lineages and A. parasiticus from other regions were evaluated. Impacts of fungi present prior to introduction of crops may cause differences in the etiology of aflatoxin contamination among regions. Characterization of fungi from non-cultivated soils may provide insight on which fungi are best adapted to the region and allow for improved aflatoxin management.