Diversity of the Aspergillus section Flavi S morphotype in Mozambique
L. ARONE (1), J. Augusto (2), R. Bandyopadhyay (3), P. Cotty (4) (1) University of Arizona, U.S.A.; (2) International Institute of Tropical Agriculture (IITA), Mozambique; (3) International Institute of Tropical Agriculture (IITA), Nigeria; (4) Agricultur
Aflatoxins are potent mycotoxins that contaminate foods and feeds worldwide. These cancer causing toxins also impair development and suppress immune systems. In Mozambique rejection of groundnuts from export markets and high prevalence of liver cancer are linked to aflatoxins. To improve understanding of contamination in Mozambique, aflatoxin producers were compared with known causal agents from other regions. Since, Aspergillus section Flavi isolates with S morphology are linked to severe contamination in North America and East Africa, relationships of S morphology aflatoxin producers to previously described fungi were characterized. Partial sequences of aflatoxin transcription factor (aflR, 2.1 kb) and nitrate reductase (niaD, 2.1 kb) genes were compared among S isolates from Mozambique, Kenya, Benin, and USA. Phylogenetic analyses sorted 200 S isolates from Mozambique into four clades. Isolates in the first clade produced only B aflatoxins and were closely related to fungi previously associated with lethal aflatoxicosis in Kenya. The other three clades produce both B&G aflatoxins. One of these contained A. minisclerotigenes and another was sister to the Kenya isolates. The third B&G clade is divergent from but most closely related to both the NRRL isolate A-11612 and fungi from West Africa belonging to an unnamed taxon referred to as SBG. Fungi in all four clades produce high aflatoxin concentrations and are potentially important causes of crop contamination.