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You can't judge a book--or, it seems, a fungus, mold or yeast--by its
cover. That's what ARS scientists are finding as they use DNA
"fingerprinting" to sort more than 80,000 yeasts, fungi and molds in the
world's largest public-accessible collection of such organisms, based at
Peoria, IL. DNA fingerprinting uses the unique aspects of each
organism's genetic makeup as a means of identification. Previously,
scientists classified organisms based on their size, shape or ability to
thrive on a specific nutrient-laden medium. Researchers say this new
identification system could help them identify disease-causing microbes
and others that can be put to work as biocontrols against crop pests,
weeds,and diseases. The genetic information also may provide important
clues to an organism's geographic origins.
Microbial Properties Unit, Peoria,
IL
Cletus Kurtzman, (309) 681-6561
Better breads and other baked goods for tomorrow may result from ARS
scientists' success with gene-engineering wheat kernels. The
scientists are the first to boost the amount of breadmaking
proteins--known as high molecular weight glutenins--in wheat kernels.
Breadmakers already know that flour high in these proteins yields light,
fine textured loaves. Researchers increased the amount of the proteins as
much as 50 percent in bioengineered wheat grown in the greenhouse. So
far, six successive generations of the plants retained this trait.
Sometime next year, the scientists expect to have enough flour from
experimental plants to bake test loaves. One tool they used in the work
is a genetic on-and-off switch called a promoter. It might work equally
well to ratchet up--or down--other key proteins in wheat kernels. This,
in turn, might lead to additional gene-engineering of wheat to yield an
array of unique new flours or innovative by-products for industrial uses.
(PATENT APPLICATION 08/586,331)
Western Regional Research Center, Albany, CA
Ann E. Blechl, (510)559-5716
Imagine taking a trip and creating the roadmap as you travel.
That's what researchers are doing as they draw the genetic map of the
domestic chicken. The scientists are identifying "markers" along strands
of genetic material called DNA, which makes up the genetic "highway" of
the chicken. They use these markers to locate sites on the DNA strand
where genes may be present that control economically important traits,
such as meatiness, egg production or disease resistance. If researchers
can pinpoint these genes, breeders could someday use this information to
select for birds to meet market demands. At the heart of the work is
information gleaned from the DNA of 52 crossbred chicks whose parents were
a domestic egg-laying chicken and a wild-type relative. ARS scientists
are also using information from the human genome mapping project to
approximate the location of particular chicken genes. By using what is
known about where certain human genes are located, scientists can get a
better idea of where to look for important genes in the chicken.
Avian Disease and Oncology Laboratory, East Lansing, MI
Hans Cheng, (517) 337-6758
Tomorrow's oats could also carry genes from corn. Researchers have
successfully crossed oats, Avena sativa, with corn,
Zea mays, in a quest to achieve better disease resistance
in oats. Corn has qualities that would come in handy in oats, like
resistance to crown rust, an airborne fungus that causes millions of
dollars of oat crop losses each year in the Midwest. The fungus has
overcome previously disease-resistant oat varieties. The cross-breeding of
the two distinct species is part of an ongoing research effort to identify
and achieve better disease resistance. No commericial varieties of
oat-corn hybrids are being produced. Scientists hope using corn as a new
source of resistance will fend off the fungus more effectively. Other
advantages corn might lend to oats: increased heat tolerance, improved
grain composition, and increased productivity.
Plant Science Research
Unit, St. Paul, MN
Howard R. Rines, (612) 625-5220
Breeders are creating new soft red winter wheat varieties that will be
more flood-and-drought tolerant. They are trying to incorporate a
genetic trait already present in some commercial U.S. soft red winter
wheats. These varieties had higher yields in Georgia soils despite a
subsurface clay layer that normally restricts roots and causes wintertime
waterlogging of soils. Flooding triggers these plants to form
aerenchyma--large air channels that connect waterlogged roots to air
spaces in plant stems. The channels allow the roots to "breathe"--meaning
they have access to air and can survive underwater. What's more, the
roots can penetrate the softened clay layer, which allows them to reach
deep soil moisture during surface droughts. The rooting tolerance to soil
waterlogging caused one of these varieties, Coker 9835, to have an average
yield of 68.6 bushels per acre,compared to 49.85 for Bales, which has no
aerenchyma. ARS scientists are working with a plant breeder and plant
cell morphologist at the University of Georgia at Athens and other
scientists to breed new commercial wheat varieties that, like rice, will
develop aerenchyma in their roots soon after sprouting, instead of waiting
for flooding.
Southern Piedmont
Conservation Research Laboratory, Watkinsville, GA
James E. Box, Jr., (706) 769-5631
Repair genes in moss may hold the key that enables crops to recover
from lengthy, crippling droughts. ARS scientists believe they have
found some of the repair genes that help star moss, Tortula
ruralis, survive total desiccation for months, then revive
seconds after being hit by drops of water. The moss recovers so quickly
because, as it starts to dry, it stockpiles the genetic material it will
use to make repair proteins when it rains. The scientists have isolated
many of the genes active during the moss' recovery stage and have focused
on one, initially, because of its similarity to other genes known to
operate after dehydration damage in seeds. They are also collaborating
with Australian scientists to identify similar drought-tolerant genes in
the livestock forage grass, Sporobolus stapfianus. This
grass protects itself against almost total dehydration. In this case, the
scientists are also looking for the genes that protect the grass tissue as
it dries.
Plant Stress and Water Conservation
Research, Lubbock, TX
Mel Oliver, (806) 746-5353
Last updated: October 21, 1996
Return to: Quarterly Report
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