Washington, DC
March 11, 2009
Source:
March
2009 issue of Agricultural Research magazine
C:\Inetpub\wwwroot\News\releases\2009\march\25423.htm
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ARS scientists are evaluating U.S. wheat lines for
rust resistance in hopes of giving U.S. wheat and barley
breeders a head start towards protecting new varieties
from Ug99, a deadly wheat stem rust in eastern Africa.
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When the threat to
a food staple like wheat is worldwide, the best way to counter
it is to enlist the world’s experts in a research coalition.
That’s just what has been done to answer the very real threat of
Ug99, a new stem rust to which most of the wheat and barley
grown in the United States and the rest of the world has no
resistance.
As part of that
global response, the
Agricultural
Research Service became a founding partner in the Borlaug
Global Rust Initiative (BGRI), in alliance with the
International Maize and Wheat
Improvement Center (CIMMYT), the
International Center for
Agricultural Research in the Dry Areas (ICARDA), the Food
and Agriculture Organization of the United Nations, and Cornell
University. The BGRI is chaired by Nobel Peace Prize winner
Norman E. Borlaug.
“To reduce the
vulnerability of U.S. and global wheat crops to Ug99 requires an
international partnership of scientists and institutions with
diverse expertise and facilities. We are fortunate that ARS was
one of the first institutions to respond to the call from Dr.
Borlaug,” says Ravi Singh, BGRI’s chief wheat scientist.
“ARS has several
of the world’s small pool of experts in cereal rust research,”
explains Kay Simmons, ARS national program leader for plant
genetics and grain crops. “We have several collaborative
research projects under way that are feeding critical
information into BGRI, and these partnerships are the best way
to leverage everybody’s resources to combat Ug99.”
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Close-up of stem rust on wheat.
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ARS is partnering
with CIMMYT and the Kenya
Agricultural Research Institute (KARI), to screen wheat and
barley lines from breeders from all over the United States for
Ug99 resistance.
Kenya has had Ug99
since 2001, so having use of the nursery there provides a way
for U.S. breeders to find out which of their new varieties and
lines may be able to stand up to the rust without bringing the
pathogen into the United States and without each wheat- or
barley-breeding project trying to start its own nursery
overseas.
More than 5,000
U.S. lines have been evaluated through this program so far.
“Everybody wins.
Not only does the United States benefit from this nursery, but
ARS is also sharing all the information from these screenings
with the other members of BGRI, and they are sharing their
results with us,” Simmons says.
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In 1999, a new strain of cereal stem rust was first
reported in Uganda, hence the name “Ug99.” It was found
in Kenya in 2001 and in Ethiopia in 2003. Now it has
spread to Yemen, Sudan, and Iran.
Stem
rust is favored by hot days and mild nights with
adequate moisture for nighttime dews, and it is spread
by the wind—conditions that can occur anywhere wheat
grows. Historically, stem rust has been the most
destructive disease of wheat and barley. ARS has found
that nearly all spring wheat varieties grown in the
United States are susceptible to Ug99, as are more than
75 percent of U.S winter wheat and most of the
commercial barley varieties.
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In fact,
researchers from other BRGI members—such as
Agriculture and Agri-Food Canada,
KARI, and CIMMYT—help score the wheats at various points in the
growing season alongside ARS scientists such as plant
pathologist/geneticist David Marshall, research leader of the
ARS Plant Science Research Unit in Raleigh, North Carolina.
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Nobel Peace Prize winner Norman Borlaug (second from
left) believes Ug99 is the most serious threat to wheat
and barley in 50 years. He is shown here consulting with
Kenyan and CIMMYT leaders near wheat plots in Kenya.
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“
Results from the
2005-2007 screenings showed that Ug99 has overcome even more
major resistance genes than previously believed,” Marshall says.
“This only emphasizes how important it is to find new ways for
wheat to deal with Ug99.”
ARS has also used
the test nursery to screen a significant portion of the
small-grains germplasm collection in search of new sources of
resistance.
The information
from this screening has helped jump-start a cooperative stem
rust-resistance breeding program at Oklahoma State University.
ARS geneticist Michael Pumphrey at the Plant Science and
Entomology Research Unit, Manhattan, Kansas, transferred new
resistance genes into germplasm that university professor Brett
Carver is now incorporating into locally adapted breeding
populations.
“What ARS
accomplished in 2 years would have taken us about 5 years,
assuming we would have enjoyed the same success in crossing with
some of the more cantankerous wild wheat relatives used in this
project,” Carver says. “This partnership allows me to remain
focused on the locally specific breeding objectives that already
have my attention.”
Opening a
New Window
Recently, the Bill
& Melinda Gates Foundation provided a $26.8 million grant to
Cornell University to create the Durable Rust Resistance in
Wheat (DRRW) project, which will help bolster Ug99 research.
With this grant, Cornell University has brought together 15
partnering institutions from all over the world, including ARS,
with the goal of systematically reducing wheat’s vulnerability
to rust diseases through an international collaboration of
unprecedented scale and scope, according to Ronnie Coffman,
DRRW’s principal investigator.
ARS is most
heavily involved in three of the project’s objectives: tracking
wheat rust pathogens, exploring whether rice offers any immunity
to rust that might be transferred to wheat, and discovering new
sources of rust resistance in wild wheat and wild barley.
Because most of
current Ug99-effective genes are derived from relatives of
common and durum wheat, ARS is looking to wild relatives as a
source of genes for new types of resistance. Preliminary studies
led by plant pathologist Yue Jin at the ARS Cereal Disease
Laboratory have found some resistance to Ug99 in einkorn,
goatgrass, and sanduri wheat.
ARS will be
joining with ICARDA and the University of Minnesota to screen
other wild relatives of wheat and barley.
“Wheat stem rust
is borne by the wind across every political boundary where wheat
is grown. To monitor it and defeat it, international
partnerships have always been essential,” Coffman says. “Since
the beginning of rust research, ARS scientists have been good
leaders and good partners, working at the forefront of science
on behalf of the world community. Without their essential
participation, the DRRW project would not be possible.”
More information
on DRRW can be found at
www.wheatrust.cornell.edu.—By
J. Kim
Kaplan, Agricultural Research Service Information Staff.
This research
is part of Plant Diseases, an ARS national program (#303)
described on the World Wide Web at
www.nps.ars.usda.gov.
Kay Simmons is the
National Program Leader for
Plant Genetics and Grain Crops, Room 4-2210, 5601 Sunnyside
Ave., Beltsville, MD 20705-5139; phone (301) 504-5560, fax (30)
504-6191.
This article, "Collectively
Facing an Ugly Rust" was published in the
March
2009 issue of Agricultural Research magazine. |
