GMO Potato: Cisgenesis is still Genetic Modification with All the Attendant Risks

The new trial on GM blight-resistant potato is being sold as cisgenic technology to confuse the public, but it is still genetic modification with all the attendant risks — most of which are not addressed.

by Dr Eva Sirinathsinghji

A new genetically modified (GM) ‘blight-resistant’ potato is currently being tested in a three year large-scale field trial in Carlow, Ireland conducted by the Irish government in collaboration with the Dutch Wangeningen University [1]. Potato blight, a devastating fungal disease caused by Phytophthora infestans, was responsible for the terrible Irish potato famine in 1845-52. The trial, started this summer, is a follow up study of the initial small-scale field trial performed in 2012.

With scepticism and distrust towards GM crops prevalent in Ireland, a country known for environmental consciousness, proponents of the new trial are attempting to further blur the scientific facts associated with the blight-resistant potatoes. These potatoes are being dubbed ‘cisgenic’ instead of ‘transgenic’, claiming that cisgenesis is the process of transferring a gene from one species to another sexually compatible one. Wageningen University and collaborating organisations have even gone to the lengths of publishing a website with spurious definitions in order to spread the confusion as far as possible (see below) [2].

So what exactly does cisgenesis and transgenesis mean? Transgenesis can be defined as the transfer of foreign genetic material into an organism by genetic engineering techniques. As is the case with this GM crop, the host potato species (Solanum tuberosum cv. Desiree) is different from the wild relative species Solanum venturii that provided the blight-resistance gene, Rpi-vnt1.1. S. tuberosum cv. Desiree does not contain the blight-resistant gene. Therefore, the transferred Rpi-vnt1.1 gene is a foreign gene i.e. transgene.

This contradicts the description on the website of a cisgenic plant as one that contains “no foreign genes”, which makes no sense when the reason they are putting in that gene is because the host plant does not have it! Most fundamentally, cisgenesis is still genetic engineering and employs the methods of transgenesis to make a GM crop with all the attendant risks. The new terminology is invented simply to deceive the public. The only difference is that the gene inserted may derive from an organism more closely related to the host species. This does not bypass any of the risks associated with standard GM procedures and as the transgene comes from a different species of potato, the protein product may indeed be different from the native non-transgenic potato. It should be recalled that the transfer of a gene between closely related species has led to proteins causing powerful immune responses [3] (Transgenic Pea that Made Mice Ill, SiS 29). The process used to generate both cisgenic and transgenic crops is exactly the same, and therefore carries the same risks which include instability and scrambling of the host genome, disruption of host genes, as well as genetic regulatory elements, generation of new nucleic acids, proteins and metabolites. In addition, the vector system used in transformation is a significant source of hazard (see below).

If one wants to delve deeper into current molecular biology, even the definition of a gene is unclear. Classically, molecular biology defined a gene as a DNA sequence that encodes a protein (via RNA), but it now turns out that there are many ‘genes’ with multiple transcription start sites within the coding region i.e. there is one ‘gene’ but multiple protein products (isoforms) [4]. There are also non-protein-coding RNAs, genes transcribed on the reverse strand to make totally different proteins, and indeed recent studies show that most of the genome is transcribed including regulatory elements such as enhancers, which do not encode proteins [5, 6]. In contrast, evolutionary scientists such as W.D. Hamilton and George C. Williams have defined the gene as a unit of natural selection, in which case a gene could be logically defined as a single base pair, as single-nucleotide polymorphisms are known to affect phenotype [7]. It is therefore deceptive for scientists to define cisgenesis as distinct from transgenesis.

What exactly is the GM potato being trialled in Ireland?

In 2012, a small-scale field trial with 24 GM and non-GM potato plants was performed to assess how well the GM potato survived Irish conditions. Starting this summer, the second trial spanning three years, will compare 1758 plants of 3 varieties: GM desiree, non-GM desiree as well as the organic blight-resistant Sarpo Mira, which is thought to contain around 5 wild blight-resistant genes. The researchers will study the effects on soil diversity, the genetic diversity of the blight strains isolated from the study, as well as the impact of an integrated pest management system on blight by the end of this year.

The GM potato was generated by researchers at the University of Wageningen as part of a wider EU project termed ‘Amiga’ which involves 22 European institutions to test environmental and agronomic impacts of GM crops in Europe [8]. The variety Solanum tuberosum cv. Desiree was used as the host variety and now carries a gene called Rpi-vnt1.1 from the wild potato species Solanum venturii.

The Rpi-vnt1.1 gene and its native promoter were inserted into the potato using Agrobacterium tumefaciens mediated transformation (ATMT). This is a common method of genetic engineering and comes with well known risks described thoroughly in our recent report Ban GMOs Now [9]. Among the risks is horizontal gene transfer to other organisms (see [10], Horizontal Gene Transfer Does Happen, SiS 38). Agrobacterium has been shown to transform at least 80 different non-plant species including fungi, yeasts, algae, mammalian and human cells. One possible mechanism of horizontal gene transfer with this GM potato is the tendency of A. tumefaciens to persist in the GM plant after the experiment is completed where it can remain dormant while still harbouring the binary vector containing the transgene(s). This provides a clear opportunity for gene escape to other plants or other organisms. There is no evidence that researchers have ascertained the absence of A. tumefaciens in the new GM potato line. Clearly, horizontal gene transfer should be investigated in the field trial. But it is not.

Furthermore, as mentioned earlier, genetic engineering is inherently an unpredictable process and evidence has shown that ATMT results in re-arranged host genomes, instability of the transgene in terms of expression level, rearrangements, duplications and truncations (see [10]). Again, there is no evidence that the researchers have characterised this transgenic line for transgene and host genome stability, or even to show where and in what form the transgene has inserted itself into the host genome. All of this information is required by the European biosafety directive (2001/18 /EC). Without the proof of genetic stability, these trials are worthless in any case, as any rearrangement of transgene inserts would result in plants that are different from the ones risk assessed, as highlighted in our report [9].

Who owns this GM potato?

The Rpi-vnt1.1 gene was originally isolated and cloned by the John Innes centre, Sainsbury Laboratory, UK in collaboration with Wageningen University. It has been patented by these Institutions along with other applicants from Plant Bioscience Limited, and universities in Utrecht and Bennekom (Netherlands) and South Korea [11]. Though Teagasc, the agriculture and food development authority in Ireland, claim there is no industry involvement in this trial, the inclusion of Plant Bioscience Limited as a patent applicant strongly suggests otherwise. This company is part owned by the John Innes Centre, the Sainsbury Laboratory and the BBSRC and claims to work as “an independent technology management company specialising in plant, food and microbial science.” Their services “are available to any researcher or research organisation that is seeking assistance and advice with protecting and commercialising new technology” on a “non-fee basis, instead taking a portion of future commercial revenues” [12]. They have previously entered into exclusive licence agreements with agritech corporations including Dow Chemical Company that were originally developed in the same public institution – the John Innes Centre [13].

Planting GM potatoes will repeat monoculture farming that caused the original famine

Working people in Ireland during the times leading up to the great famine had come to rely on potatoes as a staple food after its original importation from South America for the gentrified classes. Widespread cultivation shaped the agrarian economy and eventually resulted in mass consumption by poorer Irish workers. The cultivation of predominantly one main potato variety — the Irish Lumper — along with the high dependency on potatoes for food and livestock feed, were the two major causes of this devastation [14].

Now, it appears that the Irish government along with researchers at the University of Wageningen, are aiming to re-enact this situation, by applying the same principles of monoculture farming to the modern day version – GM monoculture cultivation.

GM Crops are not the answer to potato blight

While blight is considered one of the most devastating crop diseases, with the ability to kill leaves in 10 days, there are already non-GM blight-resistant potatoes available. As previously described by Dr Eva Novotny (see [15] GM Blight-resistant Potatoes – Who Needs Them?, SiS 47), there are at least 6 varieties already approved in the UK and are popular with farmers’ markets and the Dutchy-box scheme. GM crops on the other hand, have been shown to lower yields (see [16] US Staple Crop System Failing from GM and Monoculture, SiS 59), increase pesticide use, be harmful to human health and the environment, as well as having only short-term functionality as pests including both target insects and weeds gain resistance to the GM crops (see [9] Ban GMO’s Now- Special ISIS Report). It is only a matter of time before the blight-causing Phytophthora infestans gain resistance to this GM potato, rendering it useless on top of being unsafe and most likely more expensive than conventional varieties.


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