Scientists Develop Assay to Identify Pathogenic Fungi in a Flash

Scientists from the United States Agricultural Research Service (ARS) have developed a method to rapidly detect the genetic fingerprints of fungal pathogens. The assay can detect ten Pythium and seven Rhizoctonia species, pathogens that cost wheat growers in the Pacific Northwest $50 to $70 million annually in yield losses. The ARS scientists are now exploring the assays' commercial potential and eventual use in gathering fungal data for a risk-management system.

The assay uses laboratory-designed DNA fragments called primers to detect specific sequences of fungal DNA in soil and plant samples. Polymerase chain reaction generates millions of copies of the DNA sequence. A fluorescent signal that is measured and displayed on a computer screen at each amplification cycle's end indicates how much of the pathogen is present in the original sample. The assay can yield results in one day. Before, it was necessary to culture the fungi in the laboratory and conduct greenhouse trials to observe disease symptoms, which would take weeks. In addition, the assay is more sensitive and specific compared to conventional methods.  

For more information, read http://www.ars.usda.gov/is/pr/2008/080728.htm