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United States Department of Agriculture

Agricultural Research Service

Research Project: ECOLOGICAL BASIS FOR AFLATOXIN REDUCTION THROUGH CROP MANAGEMENT AND BIOLOGICAL CONTROL Title: Aflatoxin-producing fungi in maize fields of Sonora Mexico at varying elevations: a three year study

Authors
item Ortega-Beltran, A. -
item Jaime-Garcia, R -
item Cotty, Peter

Submitted to: APS Annual Meeting
Publication Type: Proceedings
Publication Acceptance Date: April 5, 2011
Publication Date: June 1, 2011
Citation: Ortega-Beltran, A., Jaime-Garcia, R., Cotty, P.J. 2011. Aflatoxin-producing fungi in maize fields of Sonora Mexico at varying elevations: a three year study. Proceedings of American Phytopathological Society Annual Meeting, August 4-8, 2011, Honolulu, HI. 101:S133.

Technical Abstract: Aflatoxin contamination of maize, a critical staple of billions, by Aspergillus flavus is a recurrent problem in the tropics and subtropics. Maize is produced across a broad range of elevations in the state of Sonora, Mexico. The current study evaluated the influence of elevation on the composition of aflatoxin-producing fungal communities associated with maize and the stability of those communities over time. Fungal isolates (1,230) belonging to Aspergillus section Flavi were recovered from field soil previously cropped to maize in 27 locations across 300 km at elevations ranging from 6 m to 2,100 m in the summers of 2006, 2007 and 2008. Fungal community structure was characterized for the A. flavus L strain isolates (846) with vegetative compatibility analyses utilizing nitrate non-utilizing auxotrophs. In total, 121 vegetative compatibility groups (VCGs) were detected; VCG composition varied greatly from year to year. Many VCGs that were very common in one year were rare or not detected in other years. Only 10 % of VCGs were detected in each of the three years studied while 63 % of VCGs were detected only in a single year. These results suggest that dynamics of communities of aflatoxin-producing fungi resident in agricultural fields are complex resulting in rapid shifts in composition.

Last Modified: 10/22/2014
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