www.czu.cz ; www.raupp.info

Biodiversity can be defined as a wide variety of living organisms in their
natural environment. Today most societies are aware of activities that
threaten biodiversity and are acting to reduce the risks, December 2004 by
Robert Wager.

Although critics of Genetically Engineered Food (GE food) claim that the
products of biotechnology threaten biodiversity, almost 10 years of
commercial growing experience says something different. It is becoming very
clear that growing GE crops helps reduce the impact of agriculture around
the world.

Every year hundreds of millions of pounds of organophosphate insecticides
are sprayed on crops. These broad-spectrum insecticides kill virtually every
insect on contact. The run-off from the sprays kills even more organisms in
the soil and waterways. In an ideal world we could just stop all use of
these chemicals. But unfortunately the reality of such drastic measures
would be reduced crop yields and mass starvation. So what is a caring farmer
to do?

Nature provided an answer in a soil dwelling bacterium called Bacillus
thuringiensis or Bt. These particular bacteria makes a series of proteins
that are very toxic to the target insects but virtually harmless to all
other life forms. Organic farmers have been safely using these live bacteria
for over a hundred years.

Agricultural scientists have been successful in transferring the gene for
the insecticidal protein from the bacteria to plants. The resulting
transgenic plants now protect themselves from insect pests without the need
for continued organophosphate spraying.

Around the world these Bt crops have allowed farmers to reduce the amount of
organophosphate insecticide sprayed by close to a hundred-million pounds
each year. Today only the target pest is killed in the fields containing Bt
crops and all other insects are unaffected. This means that the insect
biodiversity is not threatened in the same fields where crop yields remain
high.

Growing Bt potatoes resulted in dramatic reductions of insecticide use but,
unfortunately, the main buyers of potatoes in North America (McCain Foods
and McDonald's) have stopped buying these environmentally friendly potatoes
so the farmers have returned to growing traditional varieties and spraying
them with traditional insecticides.

Corn and cotton are the two main Bt crops grown today, but other Bt crops
are working their way through the regulatory system and will further reduce
our dependence on organophosphate insecticides in coming years.

Healthier food is an added bonus of growing Bt crops. When insect pests
damage an ear of corn, the probability of fungal infection of the corn is
enhanced. The fungi that grow on corn can produce nasty compounds
(mycotoxins) that have been linked to animal and human birth defects.
However, Bt corn has been demonstrated to have greatly reduced levels of
these mycotoxins compared to conventional or organically grown corn.

Weeds are one of the largest problems for a farmer. Weeds drain nutrients
and water from a field thereby reducing yields. The farmer can use
mechanical or chemical means to reduce the weeds in the field. Mechanical
weeding can have some significant negative consequences for soil structure,
run-off and erosion. Therefore, a reduction in mechanical weeding would
benefit the soil and the environment.

Chemical herbicide use has been a major alternative to mechanical weeding,
but it too can have some negative impacts on the environment. Fortunately,
not all herbicides are created equal. The newer herbicides have much lower
environmental impact than those used just a few years ago. The replacement
of older herbicides with the newer ones means far less impact on the soil
microorganisms and also cleaner water for frogs and fish.

Tolerance to the newer, less harmful herbicides has been engineered into
some crops. These herbicide tolerant (HT) crops allow the farmer to
effectively control weeds while adopting reduced or no-till farming. The
soil structure is enhanced, soil moisture and yields are maintained and
topsoil loss is greatly reduced. In North America alone, over a billion tons
of topsoil is saved each year by reduced tillage or no-till farming.

Approximately one-third of all food rots before it can be eaten. Often this
rot begins in the field long before the crop is harvested. Harsh chemicals
are applied to crops and the soil to slow the rot caused by fungus. Even
organic farmers use highly toxic copper compounds to slow fungal destruction
of their crops.

Research is well under way in developing fungal resistant crops that will
not require toxic chemical sprays. Soon, millions of pounds of toxic
anti-fungal chemicals will no longer be applied to the environment because
the plants will be engineered to protect themselves from fungal attack.

Just like people, plants suffer from viral infections. We have vaccines to
help us fight off viral infections like the measles or the flu. But unlike
us, a viral infection of a plant usually means death of the plant or severe
reduction of yields. Researchers have been successful in "immunizing"
certain plants against the viruses that attack them. The principle is
similar. We are given a small amount of an inactivated virus to boost our
immune system. The engineered virus resistant plants get a similar boost
with one gene from the pathogenic virus. Usually it is the surface protein
gene from the virus that is transferred into the plant.

The result is a plant variety that is no longer susceptible to virus
infection and damage. The papaya industry owes it continued existence in
Hawaii to this technology. By engineering the surface protein gene from the
Papaya Ringspot Virus (PRSV) into two varieties of papaya, there is now a
healthy, growing industry when just 10 years ago the total destruction of
the industry from the PRSV seemed inevitable. Ironically, these transgenic
papayas are also being used to protect non-transgenic papaya plants. By
encircling the non-transgenic papayas with transgenic plants the virus is
blocked from reaching the susceptible plants. The PRSV virus has been found
worldwide; consequently this particular product is of interest to papaya
growing countries around the world.

These transgenic papayas have one added gene and are immune to the
devastation of the PRSV virus. Now critics of food biotechnology are saying
that these transgenic papayas have caused "genetic contamination" of their
non-transgenic papayas. This is nonsense. The virus is already worldwide,
therefore so is the gene. If the critics like to call it "contamination"
then this type of "contamination" with only the one gene separate from the
pathogenic virus that is inserted into the papaya plant means the difference
between a healthy field and crop verses a dead field and no crop.

A similar situation has occurred in Mexico. Again the critics claim "genetic
contamination" of Mexican landraces of maize (corn) from Bt corn. So what is
the result of the Bt gene introgression into the landraces of maize? More
yield with less insecticide use and healthier food because of less fungal
mycotoxins. Mexican maize farmers are very adept at maintaining a particular
genetic makeup of their own landraces. It seems likely these added features
from the addition of one gene may be of interest to them.

From coconuts to grapes, bacterial infections do tremendous damage to
agriculture. Currently, the California grape/wine industry is facing a
devastating bacterial assault. Pierce's Disease is a bacterial infection
fatal to grape vines. A small insect called the glassy-winged sharpshooter
spreads the bacteria. Currently, millions of dollars are being spent on
insecticides to slow the northern march of this disease. Researchers have
had some progress in engineering a different transgenic bacterium to counter
the pathogenic bacterial infections of grape plants. It is ironic that at
this time there are four counties in California voting on whether to ban the
growing of all genetically engineered products. If this proposed ban is
voted in by the people of the four counties there will be nothing to stop
the devastation of the wine industry in those counties. Of course that will
be after tons of insecticides will have been used to try to slow the
disease.

The green revolution saw new breeding techniques, chemical fertilizers and
irrigation to help keep food production ahead of population growth. Today,
food production has fallen below the increasing demand of the human
population. It is well recognized that traditional breeding has hit its
maximum for yield increases. Therefore, unless we develop new ways to
increase yields, there will be tremendous pressure to bring new land into
production.

Although irrigation has greatly enhanced food production in many parts of
the world, it has also resulted in salt contamination of soils. Within the
next 30 years it is estimated that one tenth of all arable land will be lost
to salt contamination. Traditional breeding has few solutions for this, but
biotechnology has been very successful taking genes that allow a mangrove to
live in seawater, and moving them into crop plants. These salt-tolerant
plants will help keep the 750 million acres of salty soil in production.

A similar problem exists with aluminum. This common mineral threatens one
third of all arable land. With no traditional breeding answers, the best
hope is the work of plant biotechnologists, which have shown excellent
results in the lab. Hopefully, aluminum tolerance will be a common
engineered trait and, therefore, the one-third of all arable land affected
by aluminum will stay in production.

Water is essential for all life. Experts, including the UN-Food and
Agriculture Organization, have made it clear that water resources will be
critical in the coming century. Biotechnology is developing many different
drought-tolerant crops to maintain yields in water shortage conditions.
Clearly, these will be of tremendous interest in drought prone areas of the
world.

Each year Bt crops have allowed farmers to produce good yields without
spraying hundreds of millions of pounds of insecticide. Herbicide tolerant
crops maintain high yields with reduced tillage or no-till practices thereby
saving huge amounts of topsoil and protecting waterways from run-off.
Bacterial and viral resistant crops also maintain yield without the need for
insecticide spraying. The future will see drought resistant, salt and
aluminum tolerant and fungal resistant crops added to the varieties of
biotechnology products that will help preserve arable farmland.

There are three certainties: the population will continue to rise for
decades to come, people will be fed, and all agriculture has some impact. If
we want to save biodiversity, we must save the remaining wilderness.

Without a doubt the largest threat to biodiversity is converting wilderness
to farmland. Agricultural biotechnology has shown that it can reduce the
impact on the environment while maintaining or increasing yields. Therefore
its incorporation into world agriculture will help protect biodiversity.

Front Lines is a guest viewpoint section offering perspectives on current
issues and events from people working on the front lines of Canada's
technology industry. Robert Wager is a member of the Biology Department at
Malaspina University College in Nanaimo, B.C. Robert Wager has a science
degree in microbiology and a masters of science in biochemistry and
molecular biology from the University of British Columbia.

[www.globetechnology.com]
6/BNStory/Technology/

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