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Gene Use Restriction TechnologiesC Kameswara Rao

Gene Use Restriction Technologies (GURTs) are a group of tools to regulate gene expression, in different ways.  The concept is not new and there have been many conventional means to alter gene expression such as addition or deletion of genes, induced gene mutations, induced polyploidy, experimental hybridization and somatic hybridization.  However, these are difficult to manipulate with precision.  Modern GURTs protocols, such as the patented ‘Control of Plant Gene Expression’  (CPGE, US Patent No. 5,723,765, March 1998), RNA interference (RNAi) and the now well known rDNA technology, are more precise. 

The CPGE (aka Terminator Technology) allows the crop to grow normally and set seed, but the seed would not germinate as the development of the embryo was arrested.   The anti-tech activists have conducted such massive fear-generating campaigns against CPGE that made Governments of many countries prohibit the use of CPGE in agriculture.  Even the Patent holders had agreed not to use CPGE in any crop.  CPGE was not targeted at the farmer to prevent him from using the previous seasons’ seed, but this was the thrust of the anti-tech argument.

In another approach of CPGE, derogatively referred as the ‘traitor technology’, the expression of a specific desirable transgenic trait is dependent upon spraying a specific proprietary chemical, sold separately, often by the same company. 

RNA interference (RNAi, gene silencing) was awarded the Nobel Prize in 2006.  Gene silencing has gained scientific acceptance and is being deployed in several innovative products, particularly in medicine.  A variety of coffee without caffeine was developed by gene silencing, as also a ‘tearless onion’ demonstrated in February 2008.

The technology for ‘reversible transgenic sterility’ (RTS), patented a couple of years ago, allows the farmer or breeder to restore the seed’s fertility by applying an external chemical inducer.

Implications for GURTs

CPGE gained all its notoriety as unfortunately it was first demonstrated in the context of arrest of the development of the embryo making the seed unusable to raise a crop from it. 

Opponents to GURTs argue that the ‘terminator and traitor seeds’ could make farmers dependent on multinational companies (MNCs).  Profitable and sustainable agriculture depends upon quality seed of even the non-GE crops an area already dominated by the MNCs, because of large scale failure of the public sector in different parts of the world, more particularly the developing countries.
The CPGE technology essentially requires to be triggered by a chemical compound, such as a tetracycline antibiotic, to arrest embryo development, which any one should know as expensive and irrelevant to field agriculture. 

CPGE can be used safely to prevent gene flow where the commercial product is not the embryo but the endosperm as in rice, wheat and corn.  It can also be used where the crop is vegetatively propagated such as potato or grape vine.  It can be useful in producing almost seedless fruits of cucurbits or aubergines, where the seed is wholly formed of the embryo.  It would not be used when the whole seed formed of the embryo is the commercial product, as in legume crops such as chickpea, groundnut, soybean, etc.

GURTs containing crops are not designed for the marginal and poor farmers in the developing countries who use their own or a local seed.  GURTs are meant for farmers who are technologically savvy and can afford to buy hybrid GURTs-incorporated transgenic seed each season, to prevent gene flow from GE crops.  For decades, farmers who have been using branded designer seed, GE or not, are fully aware that they cannot recycle the seed as the benefits of the technology rapidly dwindle with each generation.

On the other hand, the seed companies know that it is not ethical and/or economical to jeopardize the interests of the small farmer who may recycle the seed season after season and the revenue loss to the companies from such ill advised use of seed is inconsequential.     
Derivable Benefits from the Deployment of GURTs in Crops

Despite the very vehement opposition, for reasons other than sound science, GURTs can be used to benefit.  The more important advantages are: 

a) Prevent gene flow from transgenics through pollen by producing sterile pollen or through seed by arresting embryo development.

b) Help in containing GE pharma crops that synthesize therapeutically active compounds.

c) Protect Organic Farming, since sterile pollen cannot cause cross pollination that may affect Organic Certification, though currently this is not an issue. 

d) Induced male sterility is an accepted tool in plant breeding to produce hybrids in otherwise difficult crops such as sorghum and mustards, and GURTs make this much easier than conventional methods.

e) CPGE could be a boon, if the trigger, instead of a tetracycline antibiotic, is a product of a seed pathogen such as a grain smut or a product of the host, produced in response to the pathogen’s entry into the developing grain.   Arresting embryo development in such seeds would control the transmission of the seed borne pathogen to the next generation.

f) Protect the genetic design of GE crops.

g) Prevent the unauthorized or illegal cultivation of transgenic crops.

h) Since GURTs would block gene flow from transgenic crops, their incorporation into transgenics is actually in keeping with the aims of the Cartagena Protocol on Biodiversity (Article 2) and do not threaten biodiversity as alleged by activists.

GURTs and Convention on Biological Diversity

The UN body, Convention on Biological Diversity (CBD) has slapped a de facto moratorium over six years ago on the use of GURTs in crops.  In 2006, Australia, Canada and New Zealand backed a proposal to end the moratorium on CPGE at the meetings of 8th Conference of the Parties (CoP) of CBD which rejected the proposal.  At the same meetings, another proposal for field trials and a case-by-case assessment of GURTs, concerning the potential impact on the environment, human health, and traditional agriculture and knowledge, also was rejected by a working group of the CBD.

The issue is on the agenda of the 9th CoP of the CBD scheduled for 20th to 30th May 2008, to be discussed under a) Impact of GURTs on Farmers Seed Systems, and b) A New Generation of GURTs: the Potential Impacts on Biodiversity and Food Sovereignty.  The notes accompanying these agenda items do not look positive in approach and so the possibilities that the moratorium would be lifted soon are bleak.

The major objective behind most of the GURTs is biocontainment of transgenes in GE crops and trees, to the advantage of the farmer, the consumer, biodiversity and the environment.