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United States Department of Agriculture

Agricultural Research Service

Research Project: Protective Endophytes of Maize That Inhibit Fungal Pathogens and Reduce Mycotoxin Contamination

Location: Bacterial Foodborne Pathogens & Mycology Research Unit

Project Number: 3620-42000-043-00
Project Type: Appropriated

Start Date: Jan 19, 2011
End Date: Jan 18, 2016

Objective:
The overall goal of this research is to understand how selected ecological groups of symptomless fungal endophytes from maize interact with kernel rotting pathogens and apply this knowledge to reduce disease severity and mycotoxin contamination of the grain. The results obtained through these objectives should produce novel strategies for preventing pathogen related losses in corn productivity and grain quality in a changing global environment. Specific objectives are: Objective 1: Examine the biocontrol potential of Acremonium zeae in providing an effective defense against mycotoxin producing kernel rotting fungi. Objective 2: Discover and characterize metabolites produced by fungal endophytes and pathogens of cereals that support symptomless infection and survival. Objective 3: Characterize fungal endophyte diversity in maize and develop phylogenetic systems to predict the role of novel endophytes in host-pathogen interactions. Objective 4: Determine the production and bioactivity of chitinase modifying proteins (cmp) among common fungal endophytes and pathogens of maize and examine their role in seed pathology.

Approach:
Mycotoxins produced by ear and kernel rotting fungal pathogens of corn are associated with economic losses to maize growers, grain handlers, livestock and poultry producers, and food and feed processors. The safety of mycotoxin-contaminated cereals and cereal products consumed directly by humans as well as mycotoxin residues in animal products is of critical importance to the agri-food industries and regulatory agencies worldwide. No commercial corn hybrid is able to escape aflatoxin or fumonisin contamination when exposed to extensive insect damage, high evening temperatures during kernel filling, or drought. The fungi recorded as symptomless endophytes of corn plants and grain prior to harvest belong to ecologically specialized groups whose interactions potentially influence disease development yet they remain poorly understood. The research proposes to provide new information and strategies for controlling mycotoxin production through: Investigations on the biocontrol potential of the protective endophyte Acremonium zeae; the discovery and analysis of metabolites and proteins that enable endophytes and pathogens to circumvent plant defenses or inhibit competing organisms; an examination of yeast populations in interactions with insects and other fungi; an evaluation of Penicillium subgenus Biverticillium species, known hyperparasites of plant pathogenic fungi; investigations of resistant and susceptible forms of a fungal targeted maize seed chitinase that is presumed to function in protecting seeds from pathogenic fungi; and the development of sorting systems to identify pathogen-specific symptoms of kernel infection and potential mycotoxin contamination. The potential to exploit this poorly understood endophyte-host relationship offers significant promise for protecting corn plants or harvested grain from seedling infection or mycotoxin contamination.

Last Modified: 8/27/2014
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