Scott, See McGraw, J. 2001. Evidence for decline of Amer. ginseng from
herbarium specimens. Biol. Conservation 98:25-32. Also note the news
release (pasted below your message) that appeared last Dec. 2007. Best
wishes, Donna
>>> Scott Shumway <sshumway@[EMAIL PROTECTED]
> 04/22/08 3:37 PM >>>
After 17 years I finally found an undergraduate interested in doing an
herbarium-based research project. Can you please recommend publications
that we could consult that discuss the importance of herbaria in
research and how herbarium data can be used in conservation biology?
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Forensic plant pathologists have identified the original pathogen
responsible for the first U.S. outbreak of citrus bacterial canker
(CBC), a disease that historically has imperiled the Florida citrus
industry. The project was led by Agricultural Research Service (ARS)
plant
pathologist John Hartung. He and colleagues studied plant specimens
dating back nearly 100 years that are preserved in a collection, called
an herbarium, housed at the ARS Henry A. Wallace Beltsville Agricultural
Research Center at Beltsville, Md. Historic specimens are valuable for
studying the genetics of plants and their pathogens.
The findings were described in a recent issue of the Proceedings of
the
National Academy of Sciences. ARS is the U.S. Department of Agriculture's
(USDA) chief scientific
research agency. The ongoing project is a collaboration between Hartung
and plant pathologist Wenbin Li, with USDA's Animal and Plant Health
Inspection Service, which provided funding.
The scientists selected the 90 oldest specimens from among 741
preserved
leaves, bark or fruit peels that showed symptoms of citrus bacterial
canker. They carefully cut 10 raised lesions, or cankers, from each
selection. Such cankers weaken trees, induce premature fruit drop and
reduce the value of the crop.
The researchers also developed a sensitive new technique for
extracting
and analyzing DNA fragments from the removed lesions. The team then
matched the DNA fragments with strain-specific, genetic targets taken
from a previously sequenced CBC strain.
Standard bacterial identification methods require intact DNA that has
been removed from live bacteria. The new technique is called IES, for
insertion event scanning. IES is especially useful for identifying
bacterial strains that are present in preserved specimens, in which the
bacteria are no longer viable and their DNA has been degraded.
By finding an exact match between CBC pathogens from both Japan and
Florida preserved in the herbarium specimens, the researchers revealed
the source of the original outbreak of citrus canker in Florida in 1911.
Using the new IES method to solve contemporary problems could shed light
on how bacteria are disseminated around the world, according to the
authors.____________________________________
This is one of the news reports that ARS Information distributes to
subscribers on weekdays.
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