Genetic engineering of Plants - Sustainable Solutions

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11 Δεκ 2012 (πριν από 4 χρόνια και 8 μήνες)

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Daniel Rupp
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Genetic engineering of Plants
Introduction:
Genetic engineering is a controversial subject according to a wide range of

reports and articles in the media. Some articles raise serious concerns about this

emerging technology whilst others praise the future possibilities.
The issue about cultivation of genetically modified crops has been subject to a

vast number of discussions in politic and science.
This article offers a conclusion about the aspects and properties of genetic

engineering in agriculture and crop breeding. It discusses the difference between

well-tried, old fashioned breeding and the emerging possibilities of genetic

engineering. The report mentions criticisms towards the technology, gives

examples of contemporary applications in agriculture.
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Main:
The conventional way of plant breeding was able to create a wide range of

commercial plants and crops with a variety of valuable agronomic traits. Mexican

grass has been converted into maize just as a usual grass plant from the Middle

East has been turned into wheat. Although this process of breeding has been

very successful in transforming usual plants into crop plants by increasing the

yield and improving certain abilities of those plants, the process itself took many

thousands of years to result into the type of maize or wheat as we know it today.

The process of common breeding is to a large extent a hit and miss procedure by

which the best looking plants have been sorted out for further breeding over

centuries.
An alternative to this classic way of breeding is a rapidly evolving part of

biotechnology. One of the main disadvantages of common breeding is the

limiting factor set by the diversity of species. Genetic engineering allows the

scientist to overcome those boundaries through the use of recombinant DNA

techniques.

Still the issue of genetically modified organisms also called GMOs

remains controversial. A crucial part of the European population tends to deny

the introduction of GMOs into agriculture in general, but especially for the food

production.
The critics against the manipulation of living organisms point out the complexity

of genetic and biochemical mechanisms and the possible side effects which may

result. Some claims predict the cultivation of GM crops will cause an irreversible

impact on the biodiversity of the environment due to cross breeding with

naturally occurring species. Whilst others indicate some scientific studies raised

serious health issues scrutinizing the safety of food based on GM crops.
Though due to today's rapid development of genetic engineering it is also

considered as one of the most promising fields of current research. It provides

the potential to play an essential rolr to overcome some of the serious issues of

our future . The exponential growth of our world population and especially

factors like global warming, scarce fresh water supply or the limited availability

of fossil fuels scream for new promising technologies to overcome these issues.
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How can genetic engineering be beneficial for humans?
The genetic information of almost every living cell is encoded in a massive

molecule known as the DNA. This molecule is made up from a number of

different genes which control all the properties and functions of any living

organism. The process of genetic engineering is capable to transfer genetic

information of one organism to a another and hence provides the capability to

“programme” a target organism for a certain task.
The picture shows a DNA double helix with a

pink part to indicate the presence of a

certain gene, which is responsible for the

the colour of a plant. The gene contains a

code “written” in base pairs, which are

indicated by the letters T (tyrosine), A

(adenine), G (guanine) and C (cytosine).
The colour of the plant can change if the

gene is altered by a mutation, cross

breeding or genetic engineering.
Genetic engineering is a very promising technology because it enables

researchers to modify the properties of basically any given organism, either by

introducing or erasing a component of coding DNA. A famous example of a

commercial application is a GM crop called Bt-corn.
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Bt-corn is a genetically modified version of common corn which is capable of

producing a protein which is usually not expressed by plants in all but in a soil

bacterium named
Bacillus thuringiensis.
The bacterium contains a gene coding

for a special protein with insecticidal properties.
The Bt-protein becomes activated in the gut of caterpillars, where it attacks the

wall of the intestines causing lethal damage to the insect. Hence the transferred

gene provides the crop with a resistance to a range of pests, which constitute a

common thread to a farmer's harvest.
On the left the picture shows ordinary corncobs wich were infested by the

European corn borer, a type of caterpillar. On the right a GM corn is shown which

remained untouched through the protection by the Bt-gene.
The Bt-crops are economical and ecologically valuable as the farmer has to make

less use of chemical pesticides.
The gene coding for the insecticidal toxin
was

not only introduced to maize but also to commercial cotton. Today around 50% of

the cotton cultivated world wide is genetically engineered.

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The following chart shows the increasing use of GM crops in the United States of

America. Four variations of crops are displayed containing two types of

commercially applied genetic engineering HT and Bt. HT is the short term for

improved herbicide tolerance while Bt describes the modification with the gene

from the bacterium
Bacillus thuringiensi
as mentioned above.
Soy, cotton and corn are grown on a big scale, which makes them an attractive

target for biotech enterprises. The USA is the leading country concerning the

application of genetic engineering in commercial agriculture. The biggest

proportion but also the greatest variety of GM crops grown worldwide is situated

in the US.
The graph shows the percentage adoption of GM crops in the United Staates

from 1996 to 2009. In US agriculture the application of crops as Bt cotton,

herbicide tolerant cotton, soy and corn has increased dramatically in last decade.
This figure is unique for the the US as no other country has employed such vast

proportion of genetic engineered crops. 91% of the soy beans and around 60% to

70% percent of cotton and corn are genetically modified crops.
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Countries such as Brazil and Argentina grow a significantly high proportion of

biotech corps with around 21 million hectares, but this constitutes just about one

third of the volume of GM crops grown in the USA with a total of 64 million

hectares. No other country exhibits such a trend toward genetically engineered

agriculture.
This table unravels the top 25 countries of GM crops including the farming area.
It becomes obvious that just very view countries have adopted the new

technology on a vast scale. European countries remain rather sceptical to the

emerging technology. Countries as Spain, the Czech Republic, Portugal and

Poland have GMO farming areas of around 100 thousand hectares or below, thus

exhibit an adoption far smaller than in their counterparts in south and north

America.
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Conclusion:
The majority of commercial GM crops possess improved herbicide and pesticide

tolerance. As well as pests plants are sensitive to high concentrations of toxins.

The increased tolerance enables the farmer to apply an extended variety of

herbicides and pesticides to protect his plants from pests. This trait is favoured

by companies, because it encourages the farmer to buy a combination of crop

seed plus matching herbicide, thus increasing the company's profit. Although

this trait is common among today's GM crops, it remains as one of the rather

controversial examples because of the encouragement of heavy herbicide use.
Despite the relative small variety of genetically engineered crops which are

already available, the far more interesting question is which new traits would be

beneficial for our challenging future. A elegant solution for areas affected by

drought and
salinization of soil, would be a modified crop capable to resist harsh

environmental conditions.
This new trait would be especially beneficial for

farmers in many third world countries. In very hot climate conditions plants need

to grow on dry and salty soil which dramatically reduces the chance of a

successful crop yield. Improved drought and salt tolerance is likely to play an

essential roll in feeding the world of tomorrow as fresh water supplies are

expected to become increasingly exploited.
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Evaluation:
Biotechnology will provide some crucial support to sustain the human population

on planet earth. Many new technologies are important to tackle the challenges

ahead. Genetic engineering might prove to be crucial for the production of fossil

fuels or to feed our ever growing population which is expected to crack the 7

billion mark this year. The vast application of genetic engineering in agriculture

on the two American continents show some of the capabilities, but are probably

just the beginning of the many possibilities that researchers will encounter.
The human population is dependant on plants in almost every way, from the

oxygen we breath to the food we eat. But also the many animal species, bacteria

and fungi depend on our green “friends”. Genetic engineering must be used in

considerate and responsible way to protect and eventually enhance the

biodiversity which surrounds us. Discussions are a important part of the

development process. We should carefully evaluate the possibilities of genetic

engineering against the potential side effects, because the choices we make will

finally determine the shape of our future and we all want a bright future.
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References:
Introduction:
www.eolss.net/ebooks/.../C17/E6-58-03-04.

pdf

Critics:
http://library.thinkquest.org/C004367/be10.shtml
GM Soy:
http://www.gmo-
compass.org/eng/agri_biotechnology/gmo_planting/283.usa_cultivations_2007.html
Bt-Corn:
http://www.ca.uky.edu/entomology/entfacts/ef130.asp
Traits of GM crops:

http://www.epa.gov/oppbppd1/biopesticides/reg_of_biotech/eparegofbiotech.htm
Tolerance to salt content in soil:
http://www.plantstress.com/Files%5Cengineering_salt.htm
Biofuel:
http://www.nature.com/nrg/journal/v9/n6/execsumm/nrg2336.html
Pictures and Information:
http://www.ces.ncsu.edu/resources/crops/ag546-1/
http://www.ent.iastate.edu/imagegal/plantpath/corn/ecb/bteardam.html
Graphs and Information:
http://www.isaaa.org/resources/publications/briefs/41/executivesummary/default.asp