Exploring Echinaceas Enigmatic
By Ann Perry
March 5, 2010
An Agricultural Research Service (ARS)
scientist is helping to sort through the jumbled genetics of Echinacea,
the coneflower known for its blossomsand its potential for treating
infections, inflammation, and other human ailments.
Only a few Echinacea species are currently cultivated as botanical
remedies, and plant breeders would like to know whether other types also
possess commercially useful traits. ARS horticulturist
Widrlechner, who works at the ARS
Central Regional Plant Introduction Station (NCRPIS) in Ames, Iowa, is
partnering in research to find out how many distinct Echinacea species
exist. Previous studies have put the number between four and nine species,
depending on classification criteria.
Working with Iowa State University
scientists, Widrlechner selected 40 diverse Echinacea populations for
DNA analysis from the many populations conserved at the NCRPIS. Most of these
Echinacea populations were found to have a remarkable range of genetic
DNA analysis suggested that when much of North America was covered with
glaciers, Echinacea found southern refuges on both sides of the
Mississippi River. But when the glaciers receded after thousands of years, the
groups came together as they moved northward and began to hybridize, which
might have blurred previous genetic distinctions.
The research team also analyzed the same populations for chemical
differences in root metabolites. These metabolites, which are often essential
for survival and propagation, can vary widely among species and may have
benefits for human health.
Using this approach, researchers were able to identify clear distinctions
among all 40 populations. These distinctions were organized into three
composite profiles that accounted for almost 95 percent of the metabolite
variation among the populations.
Additional analysis of metabolite variation indicated that the populations
grouped together in ways that aligned well with earlier Echinacea
species assignments that were based on plant morphology. This work suggested
that there were nine distinct species, not just four.
Results from this work were published in Planta Medica.
more about this research in the March 2010 issue of Agricultural
ARS is the principal intramural scientific research agency of the
U.S. Department of Agriculture.