ARS | Publication request: Identification of Aspergillus section Flavi in Maize in Northeastern China

Submitted to: Mycopathologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 16, 2007
Publication Date: June 11, 2007
Citation: Gao, J., Liu, Z., Yu, J. 2007. Identification of Aspergillus section Flavi in Maize in Northeastern China. Mycopathologia. 164:91-95

Interpretive Summary: Aflatoxins are natural secondary metabolites produced by the fungal mold Aspergillus flavus and A. parasiticus. Contamination of agricultural commodities by aflatoxins poses serious health hazard to animals and human beings. Identification of different species of Aspergillus section Flavi and investigation on the population dynamics in the field and in stored grains could help in monitoring the potential risk and the level of aflatoxin contamination. Aspergillus strains were identified from maize samples collected in northeastern China. A. flavus consists of 99 percent of the population. Among the A. flavus strains identified, L strains, which produce low level of aflatoxin, dominate over the S strains in the maize samples studied. Microscopic characteristics of L and S strains were observed and reported. This information could help in devising strategies in reducing aflatoxin contamination.

Technical Abstract: Species of Aspergillus section Flavi were isolated and identified in maize samples collected from a wide geographical region in northeastern China. Aspergillus flavus was identified to be the primary species in the population (99 percent) and became the potential source of aflatoxin contamination in the region. A. flavus strains isolated were classified into the S and L strains respectively based on their sclerotia morphology. Among the A. flavus strains identified, L strains dominated over the S strains in the maize samples studied. Both uniseriate and biseriate were observed in A. flavus L strain isolates. However, only uniseriate was observed in A. flavus S strain isolates. Microscopic characteristics of L and S strains were observed and reported. Some geographical differences between northeastern China and other countries and regions were discussed. This is the first study on the population dynamics of A. flavus versus A. parasiticus and the L and S strains within A. flavus in maize samples in northeastern China.