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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Food and Feed Safety Research » Research » Research Project #436857

Research Project: Soil Microbiome to Control Aflatoxin and Field Evaluation of Transgenic Corn

Location: Food and Feed Safety Research

Project Number: 6054-42000-026-13-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 1, 2020
End Date: Aug 31, 2023

Objective:
Identify and characterize soil microbiome with anti A. flavus activity to reduce aflatoxin contamination. Conduct greenhouse and/or field trials with transgenic corn lines expressing resistance-associated proteins or peptides or RNAi constructs with targeting silencing of fungal genes.

Approach:
1) Isolate new pathogen antagonistic/plant beneficial fungi from the rhizosphere and plant surface of disease-tolerant corn in Louisiana. Main target areas within each plant sample will be the rhizosphere around corn roots, areas where seed-treatment and soil-amendment are applied Soil samples detached from resistant and susceptible corn root tissues will be collected in various parts of the field at least twice (at vegetative and reproductive stages) during the growing season. The collected samples will be resuspended in sterile water and subsequently spread on microbial culture media for isolation of microbial cells. Each microbial strain isolated from the samples collected from the corn and field will be examined for their antagonistic activities against toxigenic Aspergillus flavus strains and growth-promoting activities using the established screening systems. Microbiome study will also be performed to characterize the microbial community in the disease-resistant corn plants. Analysis of the profiles of microbial communities to identify the groups specifically present in the resistant plants should be performed The microorganisms specifically associated with the disease-resistant plants will be cultured in an artificial medium to test for their beneficial effects on corn growth. 2) Conduct field evaluations of transgenic corn lines expressing antifungal proteins or peptides and/or RNAi constructs targeting fungal genes for silencing. The transgenic corn plants along with the proper controls will be grown and cobs will be inoculated with A. flavus 70 or other suitable strains to evaluate resistance to preharvest aflatoxin contamination.