

Read about research in Idaho (1998) and Maryland (1997) to develop potatoes with resistance to newer, more virulent strains of the blight fungus. Read about related fungi that cause problems for U.S soybean growers. (1997) Forensic Sleuths Use
Biotechnology to Study Irish Potato BlightBy Hank Becker March 17, 2000Forensic 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 fungusPhytophthora infestansdevastated
Irelands 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 Servicescientist Carol L. Groves at the New
England Plant, Soil and Water Laboratory, Orono, Me., and Jean B. Ristaino
at North Carolina State
UniversityRaleigh are examining the past to find clues to the future
of this fungus. Visit the U.S.
National Fungus Collections on the World Wide Web. 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
Collections, 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 dont 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,
[email protected]. U.S. Department of Agriculture |