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Flavr Savr Tomato
Transcript of Flavr Savr Tomato
of tissue culture Techniques of
tissue culture Genetic Modification Flavr Savr Tomatoes Delayed ripening technology Growing Tissue 'in vitro'
Environment controlled, manipulated and monitored.
Accelerated growth and desirable traits.
The driving force behind the success of plant tissue culture is the fact that plants are totipotent, meaning that it is possible to obtain a single type of cell from the original plant, also known as the explant, and these cells will be able to differentiate into the various types of cells necessary to form an entirely new plant. Creating a plant tissue culture involves a range of techniques, each with numerous steps and procedures to follow to ensure the greatest yield of plant tissue formation. These techniques and processes can be broken down into 3 basic stages of ‘Stage I, II & III’. Stage I, also known as the ‘initiation phase’, involves the preparation of the plant tissue through sterilisation of the surface and then the introduction into the media to begin the development of the culture. Stage II, also known as the ‘multiplication phase’ is completed once the plant culture has reached a size in which it can be divided into multiple containers containing medium which contains growth regulators such as auxin and cytokinin, which will assist in the formation of multiple shoots on each plant present in the medium. This process is then completed numerous times until the desired quantity of plants have been grown. Finally, Stage III, also known as the ‘root formation phase’, involves the introduction of hormones which induce the formation of roots, and assist in the development of each culture into full plants. The use of biotechnology techniques to manipulate DNA in an organism
express a desired trait. Ethics The History of the FLavr Savr The genetics behind
the Flavr Savr tomato Delaying ripening is the most common approach to increasing the shelf life of fruits. This approach is necessary as many climatic fruit undergo a rapid ripening process post harvest. There are a variety of techniques used to delay this process. 1. Regulation of ethylene production
Switching off genes to stop or decrease ethylene production.
eg1. The suppression of ACC synthase gene expression.
The enzyme is associated with converting S-adenosylmethionine to ACC which is the second to last step in the production of ethylene.
eg2. Inserting a ACC deaminase gene. ACC deaminase is involved with converting ACC into another compound therefore decreasing the overall amount of ACC available for ethylene production. The gene is found in a bacterium found in the soil called Pseudomonas chlororaphis. 2. Control of ethylene perception
Modifying ethylene receptors so that they do not respond to signals encoded with ethylene production.
eg. ETR1 codes for an ethylene binding protein. Plants with modified ETR1 have been shown to not respond to ethylene. Suppressing polyglactonurase activity
Polygalacturonase (PG) is an enzyme involved with the breakdown of pectin. which is involved with the structure and integrity of the cell walls. Suppression the production of this enzyme occurs by inserting an antisense copy of the PG gene reducing its production.
eg. Flavr Savr Tomato In 1994, the Flavr Savr tomato was introduced by Calgene, inc. in Davis, California as the first genetically modified organism to be commercially available and opened the gates to many more GMOs that followed afterward. Calgene and another company called Zaneca who were also producing genetically modified tomatoes entered a law suit over genetically modified tomatoes. The law suit ended with an agreement between the two companies that Calgene was allowed to make market range GM tomatoes while Zaneca would produce GM tomato processed goods. As well as adding a gene to retard the ripening process of the tomatoes, there was also another secondary gene added where a segment of the gene conferred to the resistance of the antibiotic Kanamicyn. This was added as a marker to help the identification process of the plant but had no other function. Researchers were concerned that environmental bacteria would take up the antibody resistant section of the tomatoes which would create problems in regards to human health. After the Mad Cow disease breakout in Europe, public concerns of GMOs began to rise. GMOs began getting a negative press due to the implications of dangers to public health and safety. These fears only grew when GMOs showed no sign of labeling products and media outlets terming them "Frankenstein foods". In 1997, Calgene halted production of Flavr Savr tomatoes and due to falling sales of the product, ended the Flavr Savr market indefinitely. First an antisense gene is developed for the original PG gene that expresses the production of polygalacturonase. An antisense gene is a gene that corresponds opposite to the original targets gene sequence. When the PG gene begins expression for PG protein production, the antisense will also express for an mRNA that will be the reverse of the mRNA of the PG gene. The antisense mRNA acts as RNAi and binds to the PG mRNA stopping it from binding to a ribosome structure and initiating translation. Positives on Gm crops
The potential benefits for agricultural activity due to crops with higher resistances to environmental factors such as climate, pests or diseases.
Increased yield could mean more food from less land and decrease the reliance of cultivating more land.
Plants with genetic resistances to pests and weeds would reduce the use of herbicide and pesticide.
Increase shelf life can lead to a decrease in gross wastage from storage and transportation.
Genetic engineering could lead to the removal of genes associated with allergies.
Genetic engineering can mean the production of pharmaceuticals and vaccines in plants enabling faster vaccinations of large populaces.
Genetic engineering can lead to healthier products. Negatives on GM crops
The dangers of GMOs no health (developed through public opinion.)
Genes may escape and find their way into other organisms and species. Such as herbicide resistance finding its way into weeds.
GM crops can compete with wild species which could threaten biodiversity.
Monogenetic crops may not be able to cope with environmental pressures and lead to shortages.
There could be potential risks to birds, or other non target organisms.
Small scale farmers can be negatively impacted by market dominance of a few major companies and could lead to loss of traditional farming practices.
The propriety nature of biotechnology can slow down the process of basic research,and patent protection may lead to the hindering of getting foods into developing nations.
Risk to public trust due to the refusal of labeling GM products. “To my knowledge, no systematically organized attempts to culture isolated vegetative cells from higher plants in simple nutrient solutions have been made. Yet the results of such culture experiments should give some insight to the properties and potentialities which the cell as an elementary organism possesses… I believe, in conclusion, that I am not making too bold a prediction if I point to the possibility that, in this way, one should successfully cultivate artificial embryos from vegetative cells”. (1902)
- Gottlieb Haberlandt (1854-1945) advantages and disadvantages advantages Disadvantages Had longer shelf life
It was easy to produce
Due to lengthened shelf life it was now possible to ship nation wide. Due to production costs and costs for shipping it was not profitable.
The public perception of GMOs was not in favor.
Bad breed of tomatoes were used. At the Agricultural research service in Beltsville, Maryland, researchers managed to introduce a yeast gene into a tomato to increase its shelf life. The focus on the experiment was a group of nitrogen based compounds called polyamines. Polyamines are believed to be involved in the processes that affect plant growth and development. The yeast introduced contained the product spermedine synthase, to increase the production of the protein spermidine, which is one of the compounds involved in the slowing of the ripening process in fruit. The result ended up with an increase in spermidine production and extended the vegetation growth as well as increased the tomatoes shelf life up to a week longer. - Haberlandt conducted a number of experiments on artificial medium to produce differentiated epidermis cell cultures of Ornithogalum and various other species, which were unfortunately unsuccessful.
- Tomato roots (P.R. White, 1934)
- Tobacco and carrot calluses and cambial tissues (R.J. Gautheret and P. Nobecourt, 1939),
- Shoot tips and meristems (E. Ball, 1946)
- The techniques and equipment used in the present day will soon become outdated, to be replaced with even greater technologies and processes, which are vastly more effective and efficient. Gottlieb Haberlandt Plant tissue culture specifically involves a range of techniques to establish and support the growth of plant cells, tissues and organs, under controlled, aseptic conditions, within a growth medium of a known and controlled composition of nutrients, hormones, and other necessary components, along with a source of light to enable the process of photosynthesis
- maintenance of already known plant species which may be declining in numbers
- which may be wished to be produced in greater quantities due to desirable traits such as good flowers or fruit Development of new plant species through the crossbreeding of two separate species or two plants of the same species which each have a desirable trait, to identify and isolate the desired features in each, which can then be both expressed and observed in the resultant offspring
- produce plants from seeds that have very low chances of germinating and growing,
- produce multiple plants without the need for the presence of seeds or pollinators to produce the seeds,
- mobilise the plants in the sterile containers to move them around to different locations and observe them under different conditions In 1992, Calgene submitted the genetically modified tomato to the Food and Drug Association (FDA).
18th May, 1994, the FDA finalised its evaluation of the Flavr Savr tomato and deemed it "as safe as tomatoes bred by convetional means". Why we needed the Flavr savr tomato To transport across nation or internationally
To reduce shipping and handling damage
To have a ripened tomato on the market that wasn't ethylene treated Public/Media Opinion