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United States Department of Agriculture

Agricultural Research Service

Fungal Functional Genomics
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Controlling Fungi Using Functional Genomics

Control of fungal infection is a persistent problem in agriculture. Fungal infection of crop plants can result in severe economic losses, either by hampering crop growth or yield, or by causing disease in other plants or animals. Such infections can occur prior to harvest or during storage. Some fungi produce toxic compounds that are of major concern to human health. For example, aflatoxin is a cancer-causing agent produced by the fungus Aspergillus flavus. Aflatoxin contamination is not only a food safety concern, but is also an international trade issue because of strict low levels of aflatoxin contamination allowed by countries importing agricultural products.

The Plant Mycotoxin Research Unit (PMR) is integrating two of its core disciplines, natural products chemistry and molecular biology, to develop new approaches for understanding and preventing fungal contamination. By identifying naturally occuring plant compounds that interfere with fungal growth or toxin synthesis, and determining which fungal genes are affected by the application of these plant chemicals, we can protect agricultural commodities using specific, target-gene based strategies.

Example 1 Adapted from Kim, JH et al., 2004, J. Agric. Food Chem., 52(26): 7814-7821. [PDF reprint]
 effect of vanillylacetone on Aspergillus
Bioassay showing growth inhibition of wild-type Saccharomyces cerevisiae and Aspergillus flavus by the benzoic acid derivative vanillylacetone. Scale indicates level of dilution of yeast cells from approx 1 million cells to 10 cells.
Example 2 (ibid)
 synergistic effects on A. flavus growth
Targeting genes can significantly increase lethality of fungicides when using natural products as stress agents. High throughput bioassays (top three) show yeasts missing an antioxidative stress gene (sod2) are 1000 times more sensitive to combined treatment of a phenolic (vanillylacetone) and the fungicide kresoxin-methyl than wild-type yeasts (WT) or ones where the sod2 gene is replaced (complemented) by the sodA from A. flavus. Combining the phenolic and fungicide is completely lethal to A. flavus (bottom).

Fungal functional genomics research in PMR is funded under the following CRIS project
  Molecular and Genetic Approaches to Suppressing Fungal Pathogens and Mycotoxin Contamination (410349)
and is conducted in cooperation with the Food & Feed Safety Research Unit, Southern Regional Research Center, New Orleans, LA.

Last Modified: 8/6/2013