GM Crops: Flavr Savr Tomatoes

GM Crops: Flavr Savr Tomatoes

Brian Yang 10M

Flavr Savr Tomatoes (also known as CGN-89564-2) are genetically modified tomatoes produced by the Californian company Calgene. It was the first commercially grown genetically modified (GM) food to be granted a license for human consumption. It was first sold in 1994 and was only until 1997 when production ceased due to high production and distribution costs making the tomatoes not profitable.

The aim was to allow the tomatoes to have a longer shelf-life compared to conventional tomatoes and to provide consumers with tastier and firmer tomatoes. Calgene hoped to achieve this by slowing the ripening process of the tomato to prevent softening while maintaining the tomato’s natural colour and flavour.

References

Use of Antisense Technology

Antisense Technology is a technique that uses short segments of single stranded DNA/RNA called oligodeoxynucleotide that are complimentary to a chosen sequence. In the case of antisense RNA, they prevent protein translation of certain RNA strands by binding to them. In Flavr Savr, this binding is used to interfere with a protein responsible for the production of a specific enzyme linked to the rotting of the fruit.

5. Timothy Rockey, The Transgenic Tomato,

Available at: <http://www.public.iastate.edu/~rhetoric/105H16/cofp/tmrcofp.html> [21 Apr. 2015]

The website writes a very detailed 'report' about the needs, history and concerns revolving around Transgenic Tomatoes. The writing is aimed towards average people with a slight understanding and interest in the topic. It addresses both benefits and drawbacks of such products and is informatively evaluative. A large section of the text is the results regarding the safety of the Tomatoes which is the foundations of any argument surrounding this topic. Although the site recognized as official, the information correlates with other findings found on official sites. The references are correctly sited and include trustworthy sources.

6. G. Bruening, J.M Lyons, August 2000, California Agriculture, The case of the FLAVR SAVR tomato,

available at <http://californiaagriculture.ucanr.org/landingpage.cfm?article=ca.v054n04p6> [1 May 2015]

7. XiaoZhi Lim, September 8 2014, Genetic Literacy Project, Why tomatoes taste bad, how GE could revolutionize a ‘lost’ fruit—and why you may never eat one,

available at <http://www.geneticliteracyproject.org/2014/09/08/why-tomatoes-taste-bad-how-ge-could-revolutionize-a-lost-fruit-and-why-you-may-never-eat-one/> [22 Apr. 2015]

8. Red Orbit, Flavr Savr, Available at: <http://www.redorbit.com/education/reference_library/science_1/genetically_modified_organisms/1112965696/flavr-savr/> [22 Apr. 2015]

http://wall.alphacoders.com/by_sub_category.php?id=170810&name=Green+Wallpapers&page=2

http://www.tomatocasual.com/2008/02/28/what-ever-happened-to-the-flavr-savr-genetically-engineered-tomato/

http://www.accessexcellence.org/WN/SUA12/fomi598.php

http://www.tomato411.com/tomato-varieties/virginia-4th-july-tomato/

http://imgkid.com/tomato-farm.shtml

https://sg.idtdna.com/pages/products/gene-silencing/antisense-oligos

https://charlottefresh.wordpress.com/2010/07/02/fresh-recipe-my-take-on-pico-de-gallo/

http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm352067.htm

http://luisbarbosa2.blogspot.com.au/2013/06/flavr-savr-tomato.html

1. FDA, May 17 1994, Agency Summary Memorandum Re: Consultation with Calgene, Inc., Concerning FLAVR SAVR™ Tomatoes.

Available at: <http://www.fda.gov/Food/FoodScienceResearch/Biotechnology/Submissions/ucm225043.htm> [1 Apr. 2015]

This website contains the report in which the FDA made decisions upon whether the tomatoes were safe for human consumptions. The report is very formal, with information and findings that were submitted by Calgene, and the thoughts and actions the FDA made when approving Flavr Savr Tomatoes. This report is useful in finding out information about the approval of Flavr Savr including background information, genetic testing, animal testing and the overall results of the evaluation. This site is the most unbiased source that there is regarding Flavr Savr tomatoes, and is addressed to anyone who wishes to read about the 'little' details about the emergence of the Flavr Savr Tomatoes to the commercial market. It is written in a way that requires you to have background knowledge/understanding of genetic modification.

2. Michael Winerip, New York Times, June 24 2013, You Call That a Tomato?,

Available at: <http://www.nytimes.com/2013/06/24/booming/you-call-that-a-tomato.html> [1 Apr. 2015]

This news report is directed towards consumers; people who are wanting to learn about GM Crops and in particular, tomatoes. It gives general background information in the emergence and collapse of the tomatoes. It then leads on to explain that over two decades, the majority of 'fresh fruit' have been genetically modified. From the title you can infer that the report will have some negative opinions regarding the tomatoes, despite saying this, the points are extremely valid and should not be quickly dismissed. Overall it is a great article that explains a little about the history of GM Crops, and how it has developed up until today.

3. Raymond E. Sheeshy, Matthew Kramer, William R. Hiatt, PNAS, Dec 1988, Reduction of polygalacturonase activity in tomato fruit by antisense RNA. Avaiable at: <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC282595/> [29 Mar. 2015]

This website includes links to scanned copies of the scientific principles in which Flavr Savr Tomatoes were based upon. It is highly scientific and will require a large understanding in the interactions regarding genetic modification and antisense technology. The scanned files contain information and results in which experiments were made. The authors of the reports are accurately referenced and include link to online copies of their reports. The information is thirty or so years out-dated so other sources are more reliable for information about current antisense technology.

4. Golden Harvest Organics, 1996, The Failures of the first GM Foods,

Available at <http://www.ghorganics.com/failure%20of%20the%20first%20GM%20foods.htm> [15 Apr. 2015]

As written on the title and the name of the website, it is clear that this information will be opposing the idea of GM Foods. The first half of the report is informative, giving precise information about why the tomatoes failed. However, leading towards the end, the authors decide to exaggerate and add false information including information about how the FDA were hiding information "These findings, however, was played down and not publicly communicated by the FDA". The site goes on to victimizing FDA and writing about how they lied about the information. The findings made by the FDA were made publicly available as mentioned in the first reference. Besides the sections that victimize the FDA, the information is quite reliable and informative.

Media Sources (In order of appearance)

Antisense Technology used in medical treatment

The tomatoes had to be more resistant to rotting and to do so, developers added an antisense gene which interferes with the production of polygalacturonase (PG): an enzyme that degrades pectin in the cell walls which results in the softening of fruits. This softening makes the fruit more vulnerable to fungal infections. By interfering and reducing the production of PG enzymes, it allows the tomatoes to be left to ripen on the vine and still have a long shelf life, allowing them to develop their full flavour, compared to the normal method where tomatoes were picked premature (from being ripe) and then artificially ripened with ethylene gas (acts as a plant hormone). Essentially this method aimed for the tomatoes to stay on shelves for longer and to reduce bruising during transportation/harvesting.

Antisense oligo. is binded to the RNA sequence to interfere with a protein responsible for the production of PG enzymes

Use of Traditional Breeding Methods

Tradition breeding methods involve introducing a number of genes into a plant through cross breeding existing varieties. Generally these genes will include the genes accountable for desired characteristics. It is essentially a process of trial and error to find which plants will produce seeds that will grow into plants with the ‘correct’ desirable traits.

With Flavr Savr tomatoes, the fruit was unfortunately reported as having a very bland taste. An improved flavour was later achieved through traditional breeding of Flavr Savr and better tasting varieties. The difficulties faced while breeding such a plant was that often the desired ‘flavour-some’ trait was not present or the initial slow-ripening characteristic ‘disappeared’. But over time the tomatoes obtained both the flavour and the long shelf life characteristics.

Negatives of Flavr Savr

So is Flavr Savr good or bad?

• The nutritional value of organic tomatoes was absent. Some nutritional sources claim that due to the altering of the genes, a great deal of the original nutritional values were lost.
• Initially, the Flavr Savr tomato had a very bland taste. It was described as being "a tomato that would sit around looking prettier but really tasted no better".
• Despite being 'bruise resistant', there were more tomatoes damaged during transportation than organic tomatoes. This was due to Calgene not having experience in tomatoe shipping, which increased the damages and cost of production.
• Health concerns. Calgene tested Flavr Savr tomatoes on rats and had negative responses. "In the second and third studies, however, IRDC noted gastric erosions in some animals" - FDA. Despite this finding, the FDA reported: "Based on the information Calgene has provided, no definitive conclusions can be drawn regarding the etiology(ies) of the gastric erosions." The tomatoes were approved without further investigation.

Positives of Flavr Savr

The idea of Flavr Savr is very appealing; 'naturally' ripend on the vine, decreased production costs, longer shelf live, all of which are suited towards the change in demand for food.

However, what concerns me is the process in which Flavr Savr was approved. The reports made by the FDA do not deny that Flavr Savr has been found to cause gastric erosions. However, the FDA's report states that there are

"no definitive conclusions can be drawn regarding the etiology(ies) of the gastric erosions".

The concerning fact is that the FDA didn't request further investigations from Calgene to find out whether the modification was directly linked the gastric erosions. Despite the results showing that the rate of gastric erosion was higher in Flavr Savr fed rats, the FDA writes that

"the gastric erosions as described by Calgene are no more severe in transgenic tomatoes than in nontransgenic tomatoes."

• Ability to retain natural colour and flavour. 'Traditional' methods of tomato production requires the tomatoes to be picked when premature and then artificially ripened. Because of the new genes, the tomatoes are able to obtain its full natural flavour without artificial ripening.
• Prevents softening/rotting of tomatoes. Flavr Savr tomatoes were modified to reduce the production of enzymes responsible for the weakening of the cell walls. By doing so, the tomatoes took longer to rot and in turn had a longer shelf life.
• Food security. Due to the tomatoes being pest and disease resistant, it increased the number of edible tomatoes available for transportation. In theory it increases productivity and also reduces the cost of production.

To sum up, Flavr Savr tomatoes were not thoroughly tested for potential health hazards, as a result its commercial release could have ended with serious damages to humans. However if the tomatoes had been properly tested, the results could have been more promising and successful.

Gene silenced refers to the removal of the gene responsible for the production of polygalacturonase