Trans-genetics

A       IDENTITAS

          Hari/Tanggal    : Jumat  / 20 Juli 2012

          Waktu               : 08.30-11.30

B       KEGIATAN                                        

         Trans-genetics             

C       RINGKASAN KEGIATAN

A transgenic crop plant contains a gene or genes which have been artificially inserted instead of the plant acquiring them through pollination. The inserted gene sequence (known as the transgene) may come from another unrelated plant, or from a completely different species: transgenic Bt corn, for example, which produces its own insecticide, contains a gene from a bacterium. Plants containing transgenes are often called genetically modified or GM crops, although in reality all crops have been genetically modified from their original wild state by domestication, selection and controlled breeding over long periods of time. 

In 2011, the global area of biotech crops continued to increase for the 16th year at a sustained growth rate of 8% or 12 million hectares (30 million acres), reaching 160 million hectares or 395 million acres (Figure 2).  Biotech crops have set a precedent in that the biotech area has grown impressively every single year for the past 16 years, with almost a remarkable 94-fold increase since commercialization began in 1996. Thus, biotech crops are considered as the fastest adopted crop technology in the history of modern agriculture.

In 2011, a total of 16.7 million farmers planted biotech crops in 29 countries, wherein over 90% or 15 million (up from 14.4 million in 2010) were small and resource-poor farmers from developing countries. The highest increase in any country, in absolute hectarage growth was Brazil with 4.9 million hectares and the highest proportional increase was Mexico with a 146% increase to reach 175,500 hectares.

Distribution of Biotech Crops in Industrial and Developing Countries              

Figure 3 shows the relative area of biotech crops in industrial and developing countries from 1996-2011. In 2011, almost half of the global biotech crop area of 160 million hectares, equivalent to 79.8 million hectares, was grown in 19 developing countries. It is noteworthy  that in 2011, all four countries that exhibited proportional growth in biotech area of 10% or more were developing countries; they were in descending order of percentage growth: Mexico (146% increase), Brazil (19%), India (13%), and China (11%). As in the past, in 2011, percent growth in biotech crop area continued to be significantly stronger in the developing countries (11% and 8.2 million hectares) than industrial countries (5% and 3.8 million hectares). Thus, year-on-year growth measured either in absolute hectares or by percent, was higher in developing countries than industrial countries between 2010 and 2011.

Transgenic Crops, GM (genetically modified) Crops and GM foods. The DNA sequences are altered in transgenic (GM) crops. Insert a foreign gene/silence a native gene/modify a native gene. GM foods:  foods derived from genetically modified organisms (GMOs)

How about GM food in china       

71.5% cotton cultivated in China are transgenic.

China imports 54 million ton soybean each year and 80% are transgenic.

China will continue to carry out the strategy of transgene and not cease to develop GM organisms. Currently, the crops were commercially grown, approved by the National Committee of Safety for Gene Engineering, and examined by Ministry of Agriculture：

Cotton with Bt, and Bt+CpTI developed by Chinese Academy of Agricultural Science (CAAS)

Cotton with Bt developed by Monsanto Ltd. USA

Tomato with delay-maturing,  and resistance gene to viruses

Pepper with resistance gene to CMV (cucumber mosaic virus)

Papaya with resistance to circle speck virus

If it is a 5-digit number beginning with an 8, it is GM

If it is a 4-digit number .

pay attention!!!

•          beginning with a 4, it is GM

•          beginning with a 5, it is a hybrid.

•          beginning with a 3, it was sprayed with agrochemicals.

How about cow milk? GM feeds

77% of Americans would be likely to buy products that had been genetically engineered to resist insect damage, resulting in less use of pesticides. Nearly two thirds said that they would be likely to purchase such products even if they had been engineered only to taste better or stay fresh longer.

How about in UK

No commercial GM crops are grown in UK now. UK agriculture minister Jim Paice told farmers in January, 2012  that GM crops could massively help food production, and Labour's shadow environment minister, Mary Creagh, calling for more money for GM research.

Caroline Spelman, the environment secretary, “ growing GM crops was likely to be considered as part of the solution to the drought currently engulfing much of south-east England.”  "the principle of GM technology is OK if used well."

Why use GM food

Many reason to use GM food, for example:

•         Maintain high yield, especially in developing countries.

•         Reduce uses of agro-chemicals which cause pollution.

•         Improve the nutrition quality of foods.

How to make GM crops?

1.             Choose desirable trait

2.             Clone the gene

3.             Engineer the gene

4.             Transform gene into plant

1.      Choose desirable trait

Pest Resistance: Bt crops

§  Bacillus thuringiensis protein is a delta endotoxin kills corn borers

Herbicide Tolerance: Round Up Ready crops

§  Agrobacterium tumifaciens protein with resistance to RoundUp herbicide (glyphosate)

2.      Gene cloning

The key is to identify the critical genes responsible for the desirable traits from any organisms. From Proteins:     Isolation of proteins, Sequence of amino acids, Auto-synthesis of DNA. PCR cloning of genes from genomic DNA or cDNA from any organisms (plant, animal, microbes                       

3.      Gene Sources

The genes may be cloned in the same crop species. For example, a gene was cloned via map-based approach from one rice cultivar then the gene was transferred into another rice cultivar. Even if the gene is already inside the genome, we still may make GM crops over-expressing this gene (more active). The genes from other organisms, like  Bt gene.

1.      Transform gene into plant

Take plant leaf sample, break up and develop callus on media. Callus is mass of undifferentiated cells. Transform using gene gun or other methods. Grow callus on selective media for transformants, transfer to growth media becomes plant. Other methods, electroporation, agrobacterium, whiskers. Totipotent property of plants.

1.      Backcross breeding is the final step in the genetic engineering process, where the transgenic crop is bred and selected in order to obtain high quality plants that express the inserted gene in a desired manner.

Types of Risks about GM

1. Safety concerns of foreign genes

          The foreign genes introduced into transgenic crops are often from bacteria and non-food species, like Bt gene, and their expression is greatly amplified by strong viral promoters/enhancers. In practice, that means all species interacting with the crop-plants - from decomposers and earthworms in the soil to insects, small mammals, birds and human beings - will be exposed to large quantities of proteins new to their physiology. Adverse reactions may occur in all species, including immunological or allergic responses.

          Herbicide-tolerance and insecticidal transgenic plants now almost account for 71% and 28% respectively of all transgenic crops in the world. These traits are associated with genes isolated from soil bacteria. The insecticidal Bt-toxins, isolated from Bacillus thuringiensis, are often engineered into plants in a pre-activated form, and are already known to be harmful to bees directly, and to lacewings further up the food-chain.

2. Safety concerns of random unpredictability                                     

The special safety concerns of unpredictability come both from the random, uncontrollable insertion of foreign genes into the host genome , and from the unpredictable interaction of foreign genes with host genes.

Furthermore, T-DNA can be inserted in a truncated or rearranged form, in single copies or tandem repeats at one or more sites, perhaps reflecting the instability of the gene constructs; and insertion mutagenesis  is relatively common. The inserted DNA may also influence other genes downstream or up-stream of it.

3. Safety concerns of gene constructs

Foreign genes are typically introduced as 'gene expression cassettes' each with a strong viral promoter/enhancer accompanying a gene. One viral promoter used in practically all transgenic plants is from the cauliflower mosaic virus (CaMV), which is closely related to human hepatitis B virus, and less closely, to retroviruses such as the AIDS virus. The CaMV promoter may drive the synthesis of related viruses. It is functional in most plants, in yeast, insects and E. coli.

4. Safety concerns from the uncontrollable spread of trans-genes and marker genes

Genes can spread from transgenic plants by ordinary cross-pollination to non-transgenic plants of the same species or related species, and also by secondary horizontal gene transfer to unrelated species. The most obvious effects of cross-pollination already identified are in creating herbicide-tolerant weeds and superweeds. Another special risk is the spread of   antibiotic resistance marker genes which are in a high proportion of transgenic plants. It is possible that antibiotic genes enter into food chain, or spread to other organisms. (bacteria is resistant to antibiotics?)  Now this problem was well solved. So-called marker-free transformation.

5.             Backcross GM plant into high yield crops