Scientists Identify Specific Barley Tissues Infected by
February 22, 2010
Recent studies involving the fungus
that causes the disease known as scab in barley have helped
Agricultural Research Service (ARS)
scientists identify the specific tissues the fungus infects.
The fungus Fusarium graminearum is the culprit behind scab in barley
and wheat grain crops. Scab reduces yield by causing sterility and shrunken
kernels, and contaminates the grain with mycotoxins.
Plant molecular geneticist
Skadsen at the ARS
Crops Research Unit in Madison, Wis., infected barley seed spikes with
Fusarium transformed to contain a green fluorescent protein that makes
the fungus glow neon-green when examined under a fluorescence microscope. He
found that Fusarium attacks the protruding seed tip of the developing
seed, the soft tissue connected with it (just under the hull) and, to a lesser
extent, the seeds outer hull.
Previous studies using detached barley seeds found that the fungus will
liquefy the starchy interior of the seed within five days after inoculation.
Skadsen found that, even 16 days after infection, Fusarium doesnt
penetrate the starchy endosperm when the seed remains attached to the spike.
Knowing which parts of the barley plant Fusarium attacks gives
insight into how the infection process works and where to target breeding and
biotechnology strategies, according to Skadsen. Breeders can now focus on
looking for traits that will prevent the fungus early penetration.
These findings helped Skadsen and his research team to develop gene
promoters that can be used to activate genes that defend against
Fusarium in barleys susceptible tissues. Skadsen and research
Henson are now investigating the biochemistry of susceptible barley tissues
through metabolic profiling during the first three days of infection.
more about this research in the February 2010 issue of Agricultural
Details of the studies can be found in the scientific journals Physiological
and Molecular Plant Pathology, Plant Molecular
Biology and Plant Biotechnology
ARS is the principal intramural scientific research agency of the
U.S. Department of Agriculture (USDA). This
research is part of the U.S. Wheat and Barley
Scab Initiative and supports the USDA priority of promoting international