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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Crop Bioprotection Research » Research » Publications at this Location » Publication #332353

Research Project: Identification and Validation of Insect and Disease Resistance Mechanisms to Reduce Mycotoxin Production in Midwest Corn

Location: Crop Bioprotection Research

Title: A quantitative method for determining relative colonization rates of maize callus by Fusarium graminearum for resistance gene evaluations

item Johnson, Eric
item Dowd, Patrick

Submitted to: Journal of Microbiological Methods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/26/2016
Publication Date: 8/27/2016
Citation: Johnson, E.T., Dowd, P.F. 2016. A quantitative method for determining relative colonization rates of maize callus by Fusarium graminearum for resistance gene evaluations. Journal of Microbiological Methods. 130(2016):73-75.

Interpretive Summary: Corn grown in the United States is annually susceptible to contamination by ear mold fungi. Some of these fungi can produce mycotoxins which are harmful to livestock and humans. It is imperative to identify novel ways of reducing corn ear mold contamination. Some genetic studies of corn over the years have identified regions of corn chromosomes that contribute to resisting mold contamination. These identified regions, called genes, need to be individually tested in the laboratory to confirm their suspected role in fungal resistance. We have developed a laboratory method using the polymerase chain reaction, PCR, to accurately quantify the amount of fungal infection in corn cells that can support fungal growth like corn ears. This PCR method can detect the fungus 12 hours after placement on the corn cells. We found that corn cells expressing a known fungal resistance gene contained much less fungus than corn cells expressing a gene not expected to contribute to fungal resistance. This methodology using corn cells can test putative fungal resistance genes more quickly than methods requiring the creation of transgenic plants, which are more costly to produce and maintain. The identification of fungal resistance genes can result in the creation of corn that is safer for consumption by farm animals and people.

Technical Abstract: A quantitative PCR method was developed for detecting Fusarium graminearum growing in maize callus. Fungal DNA was found 12 hours after inoculation and was correlated with visual ratings. We demonstrated the efficacy of the method to quantify fungal growth in callus overexpressing a peroxidase gene conferring fungal resistance.