Genetic use restriction technology

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Plants such as an infertile cotton strain have been made in laboratories using GURT. Cotton boll nearly ready for harvest.jpg
Plants such as an infertile cotton strain have been made in laboratories using GURT.

Genetic use restriction technology (GURT), also known as terminator technology or suicide seeds, refers to methods involving specific genetic switch mechanisms that aim to restrict the use of genetic material for agricultural purposes (domesticated crops and animals). The technology works by activating (or deactivating) specific genes using a controlled stimulus in order to cause second generation seeds to be either infertile or to not have one or more of the desired traits of the first generation plant. [2] [3] GURTs can be used by agricultural firms to enhance protection of their innovations in genetically modified organisms by making it impossible for farmers to reproduce the desired traits on their own. [3] Another possible use is to prevent the escape of genes from genetically modified organisms into the surrounding environment. [4]

Contents

The technology was originally developed under a cooperative research and development agreement between the Agricultural Research Service of the United States Department of Agriculture and Delta & Pine Land Company in the 1990s and is not yet commercially available. [5]

GURT was first reported on by the Subsidiary Body on Scientific, Technical and Technological Advice (SBSTTA) to the UN Convention on Biological Diversity [2] and discussed during the 8th Conference of the Parties to the United Nations Convention on Biological Diversity in Curitiba, Brazil, March 20–31, 2006.

Process

A GURT process that uses biological signals to make enzymes that cut out the blocker sequence. GURT process diagram.png
A GURT process that uses biological signals to make enzymes that cut out the blocker sequence.

The GURT process is typically composed of four genetic components: a target gene, a promoter, a trait switch, and a genetic switch, sometimes with slightly different names given in different papers. [4] A typical GURT involves the engineering of a plant that has a target gene in its DNA that expresses when activated by a promoter gene. However, it is separated from the target gene by a blocker sequence that prevents the promoter from accessing the target. When the plant receives a given external input, a genetic switch in the plant takes the input, amplifies it, and converts it into a biological signal. When a trait switch receives the amplified signal, it creates an enzyme that cuts the blocker sequence out. With the blocker sequence eliminated, the promoter gene allows the target gene to express itself in the plant. [4] [6]

In other versions of the process, an operator must bind to the trait switch in order for it to make the enzymes that cut out the blocker sequence. However, there are repressors that bind to the trait switch and prevent it from doing so. In this case, when the external input is applied, the repressors bond to the input instead of to the trait switch, allowing the enzymes to be created that cut the blocker sequence, thereby allowing the trait to be expressed. [7]

Other GURTs embody different approaches, such as letting the genetic switch directly affect the blocker sequence and bypass the need for a trait switch. [7]

Variants

There are two broad categories of GURTs: Variety-specific genetic use restriction technologies (V-GURTs) and Trait specific genetic use restriction technologies (T-GURTs). [8] [9] The two variants have been described as follows [4] :

V-GURTs are designed to restrict the use of all genetic materials contained in an entire plant variety. Prior to being sold to growers, the seeds of V-GURTs are activated by the seed company. The seeds can germinate, and the plants grow and reproduce normally, but their offspring will be sterile... . Thus, farmers could not save seed from year-to-year to replant. In contrast, T-GURTs only restrict the use of particular traits conferred by a transgene, but seeds are fertile. Growers could replant seed from the previous harvest, but they would not contain the transgenic trait.

V-GURTs were developed first, with patents being granted for them throughout the 1990s. T-GURTSs were developed later and are sometimes considered to be the second generation of V-GURTs. [7]

Variety specific

Variety-specific genetic use restriction technologies produce sterile seeds, so the seed from the crop could not be used as seeds, but only for sale as food or fodder. [5] When a plant reaches a given reproductive stage in its cycle, the process of activating the target gene begins. In V-GURTs, the target gene is known as a disrupter gene, and is usually a cytotoxin that degrades the DNA or RNA of the plant. This results in a non-functioning seed that cannot grow into a plant. [4] V-GURTs would not have an immediate impact on the many farmers who use hybrid seeds, as they do not produce their own planting seeds, and instead buy specialized hybrid seeds from seed production companies. However, approximately 80 percent of farmers in Brazil and Pakistan grow crops using seeds saved from previous harvests. [10] Consequently, resistance to the introduction of GURT technology in developing countries is strong. [10]

Trait specific

Trait specific genetic use restriction technologies modify a crop in such a way that the genetic enhancement engineered into the crop does not function until the plant is treated with a specific chemical. [11] [5] The chemical acts as the external input, activating the target gene. One difference in T-GURTs is the possibility that the gene could be toggled on and off with different chemical inputs, resulting in the same toggling on or off an associated trait. With T-GURTs, seeds could possibly be saved for planting with a condition that the new plants do not get any enhanced traits unless the external input is added.

Potential uses

GURTs have several uses that could benefit both businesses and farms.

Non-viable seeds produced on V-GURT plants may reduce the propagation of volunteer plants. Volunteer plants can become an economic problem for larger-scale mechanized farming systems that incorporate crop rotation. [5] Furthermore, under warm, wet harvest conditions non V-GURT grain can sprout, lowering the quality of grain produced. It is likely that this problem would not occur with the use of V-GURT grain varieties. [5] Use of V-GURT technology could also prevent escape of transgenes into wild relatives and help reduce impacts on biodiversity. Crops modified to produce non-food products could be armed with GURT technology to prevent accidental transmission of these traits into crops meant for foods. [5]

One of the original uses proposed for GURTs was to prevent farmers from reusing patented seeds in the case that typical biological patents do not exist or are not enforced. [5] Thus, T-GURTs could be used by seed companies to allow for the commercialisation of a traditional seed that gets special functions only when sprayed with a certain activator chemical sold by the company. [11]

Another proposed use is in synthetic biology, where a restricted activator chemical must be added to the fermentation medium to produce a desired output chemical. [12]

Controversy

As of 2006, GURT seeds have not been commercialized anywhere in the world due to opposition from farmers, consumers, indigenous peoples, NGOs, and some governments. Using the technology, companies that manufacture genetic use restriction technologies could potentially be able to make much more revenue because the seeds sold would not be able to be resown. Another concern is that farmers purchasing the seeds would be greatly impacted, given they would have to buy new seeds every year. It has been argued that this would result in higher prices in food. [13] Some have expressed the worry that GURT seeds might cause a significant decrease in biodiversity and threaten native species of plants. [14] [15] However, proponents of the technology dispute these claims, arguing that because non-GMO hybrid plants are used in the same way and GURT seeds could help farmers deal with cross pollination, the benefits outweigh the potential negatives. [16]

In 2000, the United Nations Convention on Biological Diversity recommended a de facto moratorium on field-testing and commercial sale of terminator seeds; the moratorium was re-affirmed and the language strengthened in March 2006, at the COP8 meeting of the UNCBD. [17] Specifically, the moratorium recommended that, due to a lack of research on the technology's potential risks, no field testing of GURTs nor products using them should be allowed until there was a sufficiently justified reason to do so. India and Brazil have passed national laws to prohibit the technology. [10]

See also

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References

  1. ↑ "Terminator Genes: Here's another fine mess biotechnology has gotten us into". Discover. 1 August 2003. Retrieved 11 December 2018.
  2. 1 2 A., Jefferson, Richard; Don, Byth; Carlos, Correa; Gerardo, Otero; Calvin, Qualset (1999-04-30). "Genetic use restriction technologies". Zenodo. doi:10.5281/zenodo.1477499.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  3. 1 2 Eaton, D.J.F.; van Tongeren, Dr. F.W. (March 2002). "Genetic use restriction technologies (GURTs): Potential economic impacts at national and international levels" . Retrieved 18 October 2018.
  4. 1 2 3 4 5 Yi Sang Reginald J. Millwood C. Neal Stewart Jr. "Gene use restriction technologies for transgenic plant bioconfinement" 04 June 2013
  5. 1 2 3 4 5 6 7 www.worldseed.org, International Seed Federation. "Genetic Use Restriction Technologies (Bangalore, June 2003)" (PDF). (Position Paper Supporting V-GURT development)
  6. ↑ "GMOs and Patents: Part 1 - Terminator Genes". www.biofortified.org. 9 December 2015. Retrieved 19 October 2018.
  7. 1 2 3 Luca Lombardo. "Genetic use restriction technologies: a review" 17 July 2014
  8. ↑ Patrick Heffer. Biotechnology: a modern tool for food production improvement in Seed Policy and Programmes for the Central and Eastern European Countries, Commonwealth of Independent States and Other Countries in Transition. FAO Plant Production and Protection Paper 168. Food and Agriculture Organization of the United Nations, 2001
  9. ↑ Jefferson RA et al. Genetic Use Restriction Technologies Archived 2014-02-05 at the Wayback Machine : Technical Assessment of the Set of New Technologies which Sterilize or Reduce the Agronomic Value of Second Generation Seed, as Exemplified by U.S. Patent No. 5,723,765, and WO 94/03619. Expert paper, prepared for the Secretariat on 30 April 1999
  10. 1 2 3 Haider Rizvi, "BIODIVERSITY: Don't Sell "Suicide Seeds", Activists Warn", Inter Press Service News Agency, March 21, 2006
  11. 1 2 "Genetic Use Restriction Technologies (GURTs)". 2007-05-04. Retrieved October 17, 2018
  12. ↑ Ledford, Heidi (February 2013). "Seed-patent case in Supreme Court". Nature. 494 (7437): 289–290. Bibcode:2013Natur.494..289L. doi: 10.1038/494289a . PMID   23426299. S2CID   4327585.
  13. ↑ "An Ethical Examination of Genetic Use Restriction Technologies" (PDF). November 20, 2008. Retrieved June 6, 2018.
  14. ↑ "Women are on the frontlines of a 'race against time' to save native seeds | Intercontinental Cry". intercontinentalcry.org. Retrieved October 17, 2018.
  15. ↑ Shiva, Vandana; Emani, Ashok; Jafri, Afsar H. (1999). "Globalisation and Threat to Seed Security: Case of Transgenic Cotton Trials in India". Economic and Political Weekly. 34 (10/11): 601–613. ISSN   0012-9976. JSTOR   4407732.
  16. ↑ "The Myth and Reality of Terminator Seeds". fafdl.org. 19 November 2016. Archived from the original on 16 May 2019. Retrieved October 17, 2018.
  17. ↑ "Moratorium". Ban Terminator. Archived from the original on 16 December 2013. Retrieved 12 December 2013.
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