Location: Biological Control of Pests Research
Project Number: 6066-42000-007-004-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Aug 1, 2026
End Date: Jul 31, 2028
Objective:
Proposed cooperative research is in support of Department of Agriculture memorandum 1078-020, priority 1: Increasing Profitability of Farmers and Ranchers and priority 2: Expanding Markets and Creating New Uses of U.S. Agricultural Products. Aflatoxin contamination of corn can be up to a $1.5B problem annually. The biological control of this problem safeguards the economic value of this $65B crop, protects human health and ensures the marketability of this commodity for farmers.
1. Evaluate spatial and temporal dynamics of Aspergillus flavus genotypes in the corn ecosystem of the Mississippi Delta.
2. Evaluate efficacy of seed-applied biocontrol isolates in colonizing grain in from treated seed
3. Evaluate role of management practices on overwintering / survival of A. flavus in agricultural soil
4. Determine if an abundant, putative biocontrol clade of A. flavus is genetically diverse or clonal.
Approach:
1. Over 2000 soil isolates of Aspergillus flavus and 2000 corn isolates of A. flavus have been obtained from the Mississippi Delta. These isolates are all geo-referenced, characterized for aflatoxigenicity and DNA extracted. Microsatellite-based genotyping has been started and will continue in this agreement. Populations will be evaluated for differences over time, geographic separation and source (soil vs. grain isolates).
2. Putative biocontrol isolates of A. flavus were applied to corn seed prior to planting. Grain was collected at the end of the season and A. flavus was collected. These A. flavus isolates were be examined for genetic similarity to the applied isolates to determine if the seed application was successful in excluding other genotypes.
3. Soil samples from an overwinter flooding experiment will be assessed for A. flavus population size and soil microbial community richness / diversity.
4. Whole genome sequencing will be performed on isolates of A. flavus collected from surveys to determine if the conserved microsatellite-based is coincident or if these isolates are monophyletic.