From isjd@ars-grin.gov Fri Mar 17 15:14:58 2000 Date: Fri, 17 Mar 2000 10:22:34 -0500 From: ARS News Service To: ARS News List Subject: Irish Potato Blight is Target of Biotech Researchers STORY LEAD: Forensic Sleuths Use Biotechnology to Study Irish Potato Blight ----------- ARS News Service Agricultural Research Service, USDA Hank Becker, (301) 504-1624, hbecker@asrr.arsusda.gov March 17, 2000 ----------- Forensic plant pathologists investigating the fungus that caused the Irish potato blight are using tools of biotechnology as an aid in their sleuthing. In 1845, a fungus--Phytophthora infestans--devastated Ireland's potato crop. The blight caused the population of Ireland to drop from 8,200,000 to 4,400,000 from disease, starvation and emigration. Hundreds of thousands of Irish people emigrated to the United States. Now, Agricultural Research Service scientist Carol L. Groves at the New England Plant, Soil and Water Laboratory, Orono, Me., and Jean B. Ristaino at North Carolina State University- Raleigh are examining the past to find clues to the future of this fungus. They have studied genetic material, called DNA, from more than 66 herbarium samples of potato and tomato lesions to find clues about the source of fungal inoculum for past late blight epidemics. The researchers have examined samples from Europe and North America, including samples from the USDA-ARS National Fungus Collection, Beltsville, Md. Looking for the fungus' fingerprints, the scientists developed primers using polymerase chain reaction (PCR) technology to specifically amplify P. infestans DNA from the samples. PCR is capable of reproducing millions of copies of the unique segments of fungal DNA that occur in a plant tissue sample. With this amplified DNA, the researchers can quickly distinguish the pathogens according to the specificity of the PCR amplification. By using PCR, scientists don't have to isolate fungi from diseased roots or leaves and spend days culturing them for identification. Rapid DNA identification of offending microbes would tip growers off to the need for control measures before fungal diseases seriously curtailed yields. So far, the scientists have found 20 specimens that tested positive for the fungus, including one from Ireland collected in 1846, and others from Britain collected in 1845, 1846 and 1847. Molecular studies of herbarium specimens of the past could open a new window to understanding and preventing future epidemics. ARS is the principal research agency the U.S. Department of Agriculture. ---------- Scientific contact: Carol L. Groves, ARS New England Plant, Soil and Water Laboratory, Orono, Me., phone (207) 581-3267, fax (207) 866-0464, cgroves@maine.edu. ---------- This item is one of the news releases and story leads that ARS Information distributes on weekdays to fax and e-mail subscribers. You can also get the latest ARS news on the World Wide Web at http://www.ars.usda.gov/is/pr/thelatest.htm. * Feedback and questions to ARS News Service via e-mail: isjd@ars-grin.gov. * ARS Information Staff, 5601 Sunnyside Ave., Room 1-2251, Beltsville MD 20705-5128, (301) 504-1617, fax 504-1648.