Rolling Out the Barrel Medic Genome
This close alfalfa relative, Medicago truncatula,
may have genes that could be useful in improving that top forage crop,
M. sativa. Funded by a 4-year National Science Foundation grant,
the barrel medic genome project includes collaborators at the Universities
of California-Davis and Minnesota and with the Noble Foundation.
Earlier work showed that many genetic markers for barrel
medic can be used to find genes in alfalfa. It identified close to 30,000
of the expressed genes that are thought to make up barrel medic's genome.
Scientists want to find genes that would give alfalfa better resistance
to diseases, enhance its ability to fix nitrogen, and improve its nutritive
quality and tolerance to stress.
New genomic techniquesand high-throughput techniques
being developedmake it possible to compare thousands of genes
at one time, to see which ones turn on or off in the presence of beneficial
or disease-causing organisms. This should improve the chances of finding
genes that play roles in more than one function. Researchers want to
know whether the I.D. tags developed for barrel medic's genes will help
them find similar or identical genes in alfalfa and possibly other crop
A. Samac and Carroll
P. Vance, USDA-ARS Plant
Science Unit, St. Paul, Minnesota; phone (612) 625-1243 [Samac],
(612) 625-5715 [Vance].
Toward Peril-Free Peanuts
Everyone with a peanut allergy will breathe a sigh of relief when scientists
find a way to produce a safer nut. As it is, U.S. consumers eat more
than 6 pounds of peanuts and peanut products each year. Legumes are
a good source of protein, fiber, vitamin E, niacin, and oleic acid,
with mostly unsaturated fat that lowers "bad" LDL-cholesterol.
But for a small yet growing group, peanuts also induce allergic reaction.
So scientists are searching for peanut cultivars that would be less
allergenic than others. To do this, they're developing antibodies against
three of the best-characterized peanut allergens, hoping to use them
to screen the U.S. core peanut germplasm collection and determine the
levels of these allergens in each cultivar. Those accessions with the
lowest levels could then be crossbred to develop a hypoallergenic peanut
The researchers, however, have noted that the roasting process itself
causes a marked increase in peanuts' allergenic properties. They've
observed specific structural, molecular, and biochemical changes that
raw peanut proteins undergo during roasting that may contribute to increases
in their allergenic properties. They theorize that perhaps it will be
possible to adjust processing methods in a way that will not increase
the allergenic properties.
Soheila J. Maleki
and Si-Yin Chung, USDA-ARS
Processing and Sensory Quality Research Unit, New Orleans, Louisiana;
phone (504) 286-4590 [Maleki], (504) 286-4465 [Chung].
This Small Bean's a Big Performer
Rojo Chiquito is the first Central American market-class bean of this
type bred for production on U.S. soils. The cultivar was developed with
Washington State University. It differs in several ways from small,
red, dry beans now grown, beginning with improved resistance to bean
common mosaic viruses. It also grows upright, rather than prone, which
helps reduce the incidence of sclerotinia white mold. This allows farmers
to plant in ultra-narrow rows for increased yield.
The shiny seeds of Rojo Chiquito are smaller than those of other small,
red, dry bean cultivars, but they stay firm and retain their dark-red
color during canning and cooking. Though Rojo Chiquito grows best in
the Pacific Northwest, field tests at 20 different U.S. locations showed
this new bean to mature in 100 days and to yield an average of 2,061
pounds per acre. Primarily developed as an export crop to meet the demand
for edible dry beans in Central America, this new variety provides an
important niche market for U.S. bean growers.
Philip N. Miklas,
USDA-ARS Vegetable and Forage
Crops Production Research Unit, Prosser, Washington; phone (509)
786-9258, or George L. Hosfield,
USDA-ARS Sugarbeet and Bean
Research Unit, East Lansing, Michigan; phone (517) 355-0110.
Vegetable Oil To Clean Up Groundwater
Scientists have found a way to use oil to clean water. Laboratory studies
show that the injection of vegetable oil into the ground can be used
to remediate contaminated aquifers. The oil stimulates microorganisms
naturally present in the aquifer to thrive and accumulate. Then, as
contaminated groundwater flows through the aquifer, these "hungry"
microbes degrade polluting compounds. Environmental firms are adopting
this idea to remove TCE (trichloroethylene) from groundwater. TCE is
a colorless toxic liquid widely used as a solvent for dry cleaning and
degreasing and has been found in groundwater beneath some military and
Pilot tests have been completed by an environmental consulting firm,
and now full-scale evaluations are under way. In laboratory studies,
vegetable oil has been successfully used to clean up groundwater contaminated
with nitrogen fertilizer; the herbicide chlorate; and perchlorate, a
component of rocket propellants.
William J. Hunter,
USDA-ARS Soil-Plant Nutrient Research
Laboratory, Fort Collins, Colorado; phone (970) 498-4208.
"Science Update" was published in the January
2003 issue of Agricultural Research magazine.