Benefits of Biotechnology - Further Down the Road
Benefits
of Biotechnology - Further Down the Road
1. Cut back loss by decay:
Browning in fruit results from the oxidation of phenolic compounds in the plant, encouraged by an enzyme called polyphenol oxidase (PPO). The PPO gene has been cloned from grapevines used to construct an 'antisense' gene whose DNA overturns the PPO's instructions to make the enzyme. The corresponding gene has been cloned for potatoes, apples, lettuce, beans and sugar cane.
By increasing a crop's ability to withstand environmental factors, growers will be able to farm in parts of the world currently unsuitable for crop production.
Along with additional food, this could also provide the economies of developing nations with much-needed jobs and greater productivity. Biotechnology will also enable growers to produce further enhancements in plant varieties. This would allow for the possibility of increasing the agricultural gene pool that billions of people rely on for basic foodstuffs.
2. Fertilizer use. Almost half of the $12 billion American farmers spend each year on fertilizer simply evaporates or washes away. As a result, much of the fertilizer used is wasted and can end up in water sources, damaging the environment.
Some plants, such as corn or rice, might be genetically modified to draw nitrogen from the soil, thereby reducing the need for fertilizer. Research here is directed to crops that require less nutrients, or can fix nitrogen themselves or form better ties with microbes that can aid them in obtaining nutrients from the soil...Nitrogen fixation seems ideal but it does involve a number of genes for both structural and enzymatic production.
3. Proteins: producing safer foods through reduction of allergenic proteins and enhanced protein quality in corn and soybeans (increased levels of lysine and methionine); see the article below on increasing the quality of rice be adding wild rice genes to a cultivated rice strain... For a real indepth treatment which shows the whole procedure, the gels and so on..see this site Engineering the Provitamin A (ß-Carotene) Biosynthetic Pathway into (Carotenoid-Free) Rice Endosperm*
4. Erosion we all know the costs of erosion..it can be cut by growing plants that are more efficient thus requiring less planting of new acreage; growing plants with stonger root systems, growing multiple crops simultaneously or shortly one after the other so that less soil is exposed and so on....
The use of no- till in which soils no longer need to be turned over has made a major contribution to reducing erosion. However it does require that weeds be killed by an alternative method, generally with chemical herbicides- another not so thrilling environmental input. By producing plants that are resistant to the herbicides, plants can kill off weeds while seeding their crops - which is a real boon ( see example on Roundup)... perhaps in the future farmers will be able to avoid even this by growing crops that produce alleochemicals naturally that inhibit the growth of other species or are better competitors ( grow faster, use resources faster) that will allow them to overgrow weeds. Multicropping ( multiple crop species growing together) will also cut back on weeds but will require some modification of current species to fit in with cropping techniques currently used.
5. Increasing a Crop's Own Ability to Fight Pests and Diseases
a. CSIRO scientists have transplanted from the common bean into garden peas a gene which protects peas from the pea weevil. The borrowed gene encodes a protein that protects against weevil attack by inhibiting a starch-digesting enzyme secreted in the weevil's digestive tract. Unable to digest their food, the larvae starve to death soon after hatching.
b. See the article below on BT resistance in cotton and its major impact in the south
Disease Resistance
Plant viruses and fungi of varying kinds often claim up to 80 percent of many crops. In much the same way vaccines immunize humans against various diseases, biotechnology allows modern breeders to insert small fragments of plant viruses into crops, which develop natural protection or immunity against those viral diseases. The immunity is passed on to future generations of plants.
Viral protection for plants will help growers of cantaloupes, watermelons, cucumbers, potatoes, tomatoes, lettuce, alfalfa and squash, as it has already increased yields for papaya farmers
a. The Freedom2 Squash and its cousins look like any other plump yellow squash, but actually they represent significant improvements. These squash varieties have been genetically engineered by the Asgrow Seed Co. of Kalamazoo, Michigan, to resist two common plant viruses. See the article on the implications of this on the last page of notes...
b. In 1991, potatoes containing a gene to make them resistant to leaf roll virus became the first transgenic crop trialled in Australia. Rather than spraying the crop with insecticeds to kill the aphids which carry the disease, potato plants are being engineered to produce proteins which interfere with the virus's ability to replicate. The resistance gene for potato leaf roll virus is derived from the virus itself and encodes the protein that forms the virus's coat.
Resistance to fungi:
Fungi have caused incredible grief to farmers.... an old but signiificant example is the Irish Potato Blight due to Phytophora...in which millions were affected and in which the history of nation was dramtically altered by the loss of crop due to this fungus....The same family is responsible for the problems with cacoa productivity currently as well with a number of other critical crops.
ARS plant pathologist Scott Abney (left) and research assistant Tom Richards check the growth of soybeans inoculated with field isolates of Phytophthora sojae. Disease reactions involving specific genes help identify the 45 races of P. sojae that have been reported in the United States.
6. Feedstock Efficiency
In the US the majority of crops are used to feed animals; obviously there are societal means to reduce this use... eating meat less or less of it at one time is one nontechnoloigcal answer.. on the bioengineering front, the idea is to create plants that are better digested by animals or contain higher quality food value so that animals need to be fed less. For example:
7. Crops as Biochemcial Factories which are degradable...
Corn and soybeans can become natural factories for production of ingredients like sucrose, lysine and methionine. These crops would essentially be recyclable and biodegradable and replace industrial factories, thus reducing stress on the environment.
8. Plant Biodiversity
It has long been known that of the more than 80,000 species of edible plants known to exist, humans cultivate only about 300 of them and of those, only 12 have emerged are used as staples. Through genetic modification, crop breeders can:
Introduce and refine new crops with desirable properties:
Colorful and tasty nuna beans will pop after a few minutes of
cooking. Someday they may appear on supermarket shelves as a
nutritious snack food. 
Increase the use of plant species by using biotechnology to discover which genes of value reside in which plants and then transferring those genes into crops now in use around the globe.
Expand the genetic variation in staple crops by breeding into them desirable traits from previously unavailable sources. This will not affect the relatively narrow genetic lineage of many crops in the near term. Longer term, it will significantly expand the gene pool used in modern agriculture and thus reduce the relatively low, but real, risk of crop failures.
9. Medical uses:
On this page review the 2 short abstracts on the use of bananas as vectors of edible vaccines and as producers of monoclonal antibodies ( soy for herpes).
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Conclusion: there really are an incredible number of potential advantages from bioengineered plants. In many cases it may take a decade to realize them. At the same time we need to be concerned about potential problems with te use of these techniques which emphasize one concern but don't address others due either to the lack of concern or ignorance. Refelcting back to our plant defense class, there is a lot we don't know about plants... they are complex biochemical organisms that have evolved with all other organisms over millions of years. To manipulate one factor without the knowledge of related connections will lead in some cases to problems we can not necessarily predict so caution is advisable, at least in my eyes...at hte same time we can't forget we already have engineered these plants through selection by farmers over the generations.. what we see now is not necessarily the wisest choice of genomes, and modification is cases may be preferrable to what exists now. On the last page we will review some of the concerns a number of scientists share.... |
GENETICALLY ENGINEERED CROPS AT VANGUARD OF AGRICULTURE DISPUTES
For Mike McCranie, the one good thing about a snowstorm that
hit Claremont, S.D., before he'd finished combining last
year is that it didn't knock his corn down -- a fact he attributes
largely to genetic engineering.
Since 1997 he's planted an increasing amount of so-called
Bt corn, genetically altered to make it lethal to corn borers.
As a result, his corn has strong stems and stayed upright
despite snow and wind.
Bt corn -- the common name for corn that has been genetically
altered to have the insecticide properties of a certain
soil bacterium -- is one of two genetically altered crops
the Claremont farmer is using. The other is Roundup Ready
soybeans, so called because they stand up to the herbicide
Roundup. For McCranie, the products illustrate the huge changes
genetic engineering is making in agriculture.
"The technology can be compared to the introduction of the
plow. Or maybe a better comparison would be going from horses
to tractors. I think that's the kind of change it's going
to make in agriculture."
Alan Scott of Britton, an area agronomist for Pioneer Hi-Bred
International Inc., agrees this is a time of enormous change,
with genetic engineering, or biotechnology, offering the
ability to tailor crops to resist a pest or chemical or to
produce food or fiber with specific traits -- corn that is
higher in oil, for example, or feeds that reduce phosphorous
in animal waste. "At this point it seems to be the next revolution
in farming, as we see it."
A Monsanto promotional video about genetic engineering is
titled "Seeds of Innovation" -- and that's the apparent view
of many. President Clinton awarded the National Medal of
Technology in April to four Monsanto scientists for developing
a simple and reliable method of transferring desirable genes
into plant species.
Monsanto's Internet site notes that genetically engineered
crops are being grown in five industrialized and three developing
nations.
If there's a revolution under way, area farmers probably
started experiencing it in 1996. That's when both Bt corn
and Roundup Ready soybeans -- two crops that occupy a huge
acreage in the area -- were made commercially available.
And although genetically engineered varieties of several
other crops are in commercial use in the United States this
growing season -- tomatoes, potatoes, squash, cotton, canola,
chicory, papaya -- corn and soybeans are still the ones
area producers are discussing.
Here's background on Bt corn and Roundup Ready soybeans,
gleaned from university or private industry Internet sites:
Bt corn takes its name from Bacillus thuringiensis, a naturally
occurring soil bacterium. It was identified as having the
properties of an insecticide in the early 1900s and starting
in the 1930s was used in gardening, agricultural and forestry.
The naturally occurring strains of Bt remain especially important
as a biological pesticide used by organic farmers.
What's different about Bt corn is that the insecticide properties
of the bacteria have actually been made part of the corn.
It's done by extracting the portion of DNA that creates the
Bt toxin from Bt bacteria and transferring it to the corn.
The result is a genetically altered corn that produces its
own Bt toxin.
The European corn borer -- with a population cycle that peaks
every five to seven years in area states -- dies shortly
after eating the Bt altered plant. When insects don't bore
through the stalks, more nutrients can enter the plant,
making for larger yields in some cases.
A 1996 study at four University of Minnesota Agricultural
Experiment Stations found Bt hybrids from one seed company
outperformed their unprotected counterparts by five to 12.5
bushels per acre. But the same study -- which included Bt
corn from two seed companies -- concluded, "Yields varied
markedly. Presence of Bt was not a guarantee of higher yields,
with some non-Bt hybrids having higher yields even when
infected by corn borer."
McCranie said his Bt corn yielded about 15 bushels more than
his conventional corn two years ago, when corn borer numbers
were high. Last year, with fewer insects, his Bt corn yielded
about seven bushels better than his other corn. McCranie
calculated the advantage was still enough to make the more
pricey Bt seed worth the cost.
Depending on the hybrid, a 50-pound bag of Bt corn seed costs
about $24 more than conventional corn. Depending on variety
and seeding rate, that breaks down to perhaps $7 to $10 more
per acre than conventional corn, Scott estimated.
Roundup Ready soybeans were developed after scientists found
a gene tolerant to Roundup herbicide in a bacterial source
commonly found in soil and transferred it to the soybean
plant. Roundup works by interfering with production of a
protein that is found only in plants. Conventional soybeans
can't stand up to Roundup. Roundup Ready soybeans differ
from conventional varieties in that they have a single added
protein, an enzyme tolerant to the herbicide Roundup. Farmers
who use the genetically altered soybeans spray for weeds
with Roundup herbicide, thus increasing yields.
The cost of Roundup Ready soybeans is about $8 more than
conventional soybeans for a 50-pound bag of seed. That breaks
down to about $10 to $11 more per acre, Scott estimated.
But the new technology raises questions -- even with people
who embrace it, like McCranie. "I don't classify myself as
a tree hugger, but I do have concerns about all this technology
coming at us," he said, adding that he worries about the
possibility of a supernoxious weed or pest developing resistance
to what seems now like a great new tool.
Greenpeace and the International Organization of Organic
Agricultural Movements, or IFOAM, voiced those concerns
as early as September 1997. They worried that introducing
the Bt gene into corn, cotton and potatoes -- three crops
that covered about 3 million acres in the United States in
1997 -- could "create resistance within the populations of
the targeted insects and thus create the need for new chemical
or biotechnological pesticides -- a well-known effect with
many chemical insecticides."
McCranie, who gets his Bt corn from a Pioneer Hi-Bred dealer,
said it's partly with that thought in mind that he's careful
to observe company guidelines about leaving a "refuge area"
-- that is, he reserves 10 percent of a Bt-planted field
for conventional corn. By such areas, the seed industry is
trying to maintain a base population of insects that remain
vulnerable to the Bt corn.
"It's time-consuming to leave that refuge area if you've
got your planter full of Bt corn," McCranie said. "It's
something we need to adhere to because we want this technology
to last as long as possible. We don't want the corn borers
to build up a resistance."
If insects do become resistant, Greenpeace and IFOAM point
out that organic farming -- a $4.2 billion industry in the
United States alone -- may be left without a biological pesticide
it's relied on for years.
For McCranie, one of the best things about Bt corn is that
he doesn't have to spray for corn borers. "That in itself
is an advantage to the environment. When you use an insecticide,
you not only get rid of the corn borer, you get rid of the
helpful insects, too."
He sees a similar advantage in Roundup Ready soybeans because
Roundup is less of a worry to the environment than some herbicides.
Manufacturer Monsanto's information about the chemical on
the Internet says Roundup's active ingredient is glyphosate,
which binds tightly to soil on contact, making it "extremely
unlikely" that it will get into groundwater or be picked
up by the roofs of off-site vegetation. Soil microorganisms
break it down over time into natural products such as carbon
dioxide, Monsanto says.
Still, with either crop, wind drift -- of chemical spray
or of Bt corn pollen -- poses potential new problems.
That's the point the Fullerton, N.D.-based Northern Plains
Sustainable Agriculture Society noted in an April newsletter,
saying "new technologies ... always bring new liabilities."
The newsletter says courts already have recognized liability
if spray drift destroys another crop. It goes on to say
the new development with biotechnology is "genetic drift"
-- if pollen from a field of Bt corn finds its way into a
field of traditional corn, for example. That could financially
damage organic farmers or those who grow for so-called "clean"
or "below detectable level" markets.
"An increasing number of farmers have found premium markets
for crops that have not been genetically modified, and they
stand to lose those premiums if the genetically modified
crops out-cross and contaminate them," the newsletter said,
noting that testing programs are already in place to verify
that crops are "genetically natural."
Theresa Podoll, executive director for the Northern Plains
Sustainable Agriculture Society, said organic farmers want
to avoid confrontations with neighbors who raise genetically
engineered crops. The newsletter suggests the solution may
be as simple as neighbors visiting back and forth to learn
when each is planting, and staggering maturity dates so
that Bt corn is not pollinating at the same time as natural
corn.
It also suggests that farmers who plan to grow transgenic
crops check with their insurance companies to ensure they
are protected by liability coverage for lost crops or markets;
that they get the latest information on genetic drift from
the extension service; and that farmers try to contain spray,
using hooded ground sprayers if possible.
Bob Hall, an extension crop specialist at South Dakota State
University, said those are valid concerns -- and not only
for organic farmers. He said spray drift from a field of
Roundup Ready soybeans could as easily damage a neighbor's
conventional soybeans that aren't destined for the organic
market.
In either case, Hall said the advent of biotechnology poses
new challenges, even while it promises to enhance yields
or add value to crops. "A lot of this stuff is going to
be quite emotional. It looks like farmers are going to have
to coordinate among themselves how they do things. You've
got to be a good manager and you've got to be on your toes."
Industry perspectives on genetic engineering are available
on the Internet. For starters, try www.monsanto.com, or
a related site, www.RoundupReady.com. A good one that includes
a wealth of material about Bt corn and European corn borer
is http://204.233.143.129/usa/crop-management/nc/ecbintro.htm.
For university and extension reports -- and there are plenty
-- simply do a search on Bt corn or Roundup Ready soybeans
on any Internet search engine.
More on the organic industry's concerns about genetic engineering
can be found at http://ecoweb.dk/ifoam, the Web site of the
International Federation of Organic Agriculture Movements.
More about consumer concerns about genetic engineering --
including resistance to genetically engineered products in
European markets, in particular -- is available at www.greenpeace.org.
Source: Aberdeen American News, S.D.
Knight Ridder/Tribune Business News
ex: WILD RICE GENE s //By Sean Henahan, Access Excellence
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ITHACA, N.Y. (Nov. 22, 1996) A batch of genes freshly isolated from variety of wild rice greatly increase production of domestic species when inserted into the plants' genome. The discovery provides a possible new way to reduce global hunger, say researchers.
Caption: Gene Gun
"We've gone back and found wild species that contain genes that may help us boost production," said Steven D. Tanksley, Cornell's Liberty Hyde Bailey Professor of Plant Breeding and Biometry. "The world is only so big, the population is growing and we need to continue feeding that population."
The discovery follows efforts by Cornell University plant breeders to create genome maps of domestic and wild rice species. The researchers have been systematically mapping genes of rice varieties and looking for the specific loci or genes -- known as the Quantitative Trait Locus, or QTL -- that would tend to boost production. Before molecular genetics, breeders had no way of finding the genes from the wild species, because there was no way of identifying the functions of the genes in the wild species.
"Essentially, we are mining the wild species for previously undiscovered genes," Tanksley said. "There is no way to effectively identify these genes through traditional methods, so we have turned to recently developed genetic techniques. We hope to reverse the genetic erosion and selectively enrich the genetic base of crop plants. Results from this research demonstrates that genes in wild rice and other wild relatives of crop plants can do spectacular things. All we're doing is using modern techniques to find those genes and harness them for human food production."
Through gene-mapping activities, the researchers deduced that the wild rice O. rufipogon contained two production-boosting QTLs: simply named YLD1 and YLD2. By recombining the QTL of the wild variety with the domesticated one, the researchers obtained between a 15 percent and 17 percent improvement in production.
Not only is rice being genetically mapped, but other researchers throughout the world can tap into a Cornell information Web site and use that mapping data to boost rice production in their parts of the world.
"Land mass is actually shrinking in Asia and as a society we've increased rice yields per acre about as much as we could. We can't increase the land, so we have to do something. Fertilization is no longer an effective way to boost yield -- it's plateaued. So, instead of boosting land mass -- which we can't do -- we're manipulating the plant's genetics," explained Susan R. McCouch, Cornell assistant professor of plant breeding,
In the case of rice, there has not been a significant yield increase in two decades. Yet the world's agriculturists are using only 25 percent of the genetic diversity available. In other words, the same types of rice have been cultivated over and over again, effectively reducing rice's natural diversity. With so much homogeneity, rice has reached a genetic bottleneck. Using genes from the wild versions of crops, such as rice, means the scientists are re-introducing the crop's natural diversity -- and increasing the yield, she notes.
From 1965 to 1995, the world's population doubled to reach its current size of 5.7 billion people. With global estimates of 8.9 billion people to feed by the year 2030, the Cornell scientists are looking for ways to improve production of staple food crops. "We've been breeding rice for 70 years, with the same set of rice types," McCouch said.
China produces 40 percent of the world's rice. The Cornell scientists collaborated with the Hunan Hybrid Rice Institute, in the People's Republic of China and provided the Chinese agricultural field station with recombined and introgressed rice.
The research appears in the journal Nature, (Nov. 21, 1996).
* Expand via cloning many wild relatives of modern crop plants that might be threatened with extinction.
* Finally, enable scientists to learn what important genes are actually contained in the millions of plant specimens housed in gene banks around the world.
FLOWER POWER GENE
By Sean Henahan, Access Excellence
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LA JOLLA, CA- Independent research teams have identified two genes that can transform ordinary shoots into flowers. And they have gone one step further, introducing the flower-stimulating genes into different plants, making them flower on demand.
The humble weed 'Arabidopsis thaliana' is the botanical equivalent of the drosophila fruit fly, the geneticist's favorite creature. Like the fruit fly, Arabidopsis has a relatively small genome that has been studied in depth. Arabidopsis would never flower were it not for a gene called LEAFY. When activated, the LEAFY gene transforms tissues that would normally form shoots to become flowers instead.
Researchers at the Salk Institute, in collaboration with another team in Sweden were able to demonstrate that leaving the LEAFY gene in the 'on' position makes the plant develop flowers much sooner than normal, and converts all lateral shoots into solitary flowers. The researchers then were able to introduce this gene into the completely unrelated aspen, creating a new transgenic hybrid. When the Arabidopsis LEAFY gene was forced to express itself, the aspen flowered much earlier than usual.
Another research team, made of scientists from the University of Arizona, Tucson, and University of California, San Diego, describe a similar result with a different gene, APETALA1. The team determined that this gene is also involved in transforming shoots into flowers and that keeping the APETALA1 gene in the 'on' position had much the same effect: converting shoots into flowers, and forcing much earlier flowering.
The researchers believe that the LEAFY gene is probably conserved in many unrelated plant species. This means it might be possible to manipulate the blooming of virtually any human food crop.
The leaves and flowers of Arabidopsis derive from the shoot meristem which is made of undifferentiated cells. In nature, a procession of genes responding to environmental cues regulates the development of leaves, inflorescences and flowers. Now, for the first time, scientists have been able to interrupt this order of events, by stimulating expression a single gene to confer floral identity on the undifferentiated cells. These findings will help researchers understand the diversity of growth and blooming seen in different species of plants.
The research is also likely to lead to applications in biotechnology. It might be possible to engineer crops to flower in different geographic locations with different growing seasons. Indeed, attempts to develop novel transgenic corn is now underway. The discovery could also speed up tree breeding programs now limited by the long life-cycle of trees. The research might also lead to non-agricultural applications, such as ornamental plants with unusual flowering patterns.
Update on Bt Cotton and Transgenic Crops //Crop and Soil Environmental News, December 1996 //Charles Hagedorn,
In the August update, the Bt cotton situation in Texas and the Mississippi Delta was examined as intense weevil pressure had resulted in insecticide applications to substantial acreage of Bt cotton. On a more positive note, two major advances in cotton production - boll weevil eradication and Bt cotton - came together in Alabama this year to reverse what appeared to be a hopeless cotton production situation. The boll weevil eradication program is finally working and 75 percent of the state1s cotton was planted in Bollgard cotton in 1996. These two advances have provided a near-perfect environment for growing cotton at a significant level of profit.
Alabama producers went from a worst-case scenario in 1995 to the best of times in 1996. Some growers went from 13 insecticide applications last year to zero this year and a significant portion of the cotton in Alabama was not sprayed at all. In 1995, Bt cotton was not available and weevils still were being cleaned up. This year, insecticides to control weevils were applied on a very small percentage of the acreage (about five percent). The Boll Weevil Eradication Program is finally taking out a pest that's been in the cotton production system for approximately 80 years. This occurred in the same year that more than 70 percent of the state's cotton acreage was planted in Bollgard varieties - varieties that are resistant, in most cases, to budworms and bollworms. Alabama's weevil eradication program began in September of 1987, in the southern region of the state, and has now expanded to all of the cotton producing areas.
The weevil eradication program fits in well with the new Bt cotton varieties. In contrast, growers in the Delta still face serious insect control problems because they have to over-spray Bt cotton every five days for boll weevils. This takes out beneficial insects, and beneficials play a vital role in Bt cotton. The full benefits of Bollgard cotton will never be felt in those areas that still have boll weevils. The remainder of the Cotton Belt will have to proceed with eradication programs before growers can get the full benefit of Bt cotton. The Boll Weevil Eradication Program, combined with Bt cotton, has revitalized Alabama's agricultural economy. Cotton estimates for 1996 are 700-pounds-per acre statewide average yield. This is a tremendous contrast to 1995, where the cotton crop in Alabama was described as a failure, and points out in graphic terms the importance of protecting the Bt mechanism to prevent insect resistance to Bt.