World-wide research

These selected papers cover a variety of topics related to genetic modification of plants. They were selected for their scientific merit and because many of them shed light on the issues related to Scion’s genetic modification research programme. We have provided summaries and links to the papers where originally published. 

Please contact us by email at Scion if you are unable to access the full-text version of any of these publications.


Biosafety discussions

Strauss, S. H., Tan, H., Boerjan, W., & Sedjo, R. (2009). Strangled at birth? Forest biotech and the Convention on Biological Diversity. Nature Biotechnology, 27, 519-527

This paper discusses how the Convention on Biological Diversity (CBD) has become a major focus of activist groups that wish to ban field research and commercial development of all types of GM trees.

Negotiated under the United Nations Environment Program, the CBD entered into force in December 1993. The aim of the CBD is to promote the conservation and sustainable use of biodiversity, and the fair and equitable sharing of benefits from the use of genetic resources.

Because biotechnologies are viewed in the CBD as having substantial potential benefits for biodiversity and sustainability, the goal of the Cartagena Protocol is not to prevent the use of transgenic or other biotechnologies but to guide their wise and safe use. But it is the risks, not the potential benefits, to biodiversity that have received the large majority of attention, owing mainly to the predominantly negative views of GMOs by some EU member states and non-Governmental Organisations (NGOs).

Recent efforts to influence CBD recommendations by NGOs in particular has led to the adoption of recommendations for increased regulatory stringency that are inconsistent with the views of most scientists and most of the major environmental organisations.

To move forward, improvements to regulations are needed that allow field research to be conducted at a reasonable cost and under workable levels of confinement.

Issues that are central to safe deployment of GM trees can only be addressed by permitting medium- to large-scale release of transgenic trees over a full rotation. Current regulations restricting field releases of all transgenes in both time and space need to be replaced with regulations that recognise different levels of risk (as determined by the origin of the transgene, its impact on reproductive fitness, and non-target impacts), and consider potential benefits, and assign a commensurate level of confinement." Ecologists and biotechnologists largely agree that without field studies, science-based regulatory decisions are not possible.

By recommending increased stringency (precaution) for all kinds of GM trees, the CBD is making the very studies needed to resolve regulatory quandaries increasingly difficult and in many places impossible. The effective prohibition on all types of GM trees that negotiations surrounding the CBD recommendations are helping to promote is clearly against both its spirit and intent.

Walter, C., Fladung, M., & Boerjan, W. (2010). Correspondence: The 20-year environmental safety record of GM trees. Nature Biotechnology, 28, 656-658.

This is a commentary on the publication by Strauss et al. (above).  In that paper, Strauss and colleagues point out that activities against genetically modified (GM) organisms have increased attention to trees, and that encouraged regulatory impediments to undertaking field research. Strauss et al call for more science based evaluation of the value and environmental safety of GM trees, which requires field trials. However, the regulatory impediments being erected by governments around the world, make the needed field testing costly or impossible in most countries. They strongly advocate a case by case regulatory system that focuses on traits and their novelty, rather than the methods used to develop the traits, and stress that any evaluation is made on scientific grounds.

In this commentary, Walter and colleagues suggest the extremely precautionary perspective taken by regulators is disappointing given that GM trees have been safely evaluated in greenhouse as well as field conditions, and the results published since 1988. They point out there is a very large amount of performance and safety data related to GM crops and trees - a recent example is the International Symposium on the Biological Safety of GMOs held in Wellington, New Zealand 2008. A search in publicly accessible databases world-wide revealed more than 700 field trials with GM trees (including forest trees, fruit trees and woody perennials), and none of them have reported any substantive harm to biodiversity, human health, or the environment. The paper provides brief examples of GM trials with forestry species.  

Taniguchi, T., Ohmiya, Y., Kurita, M., Tsubomura, M., Kondo, T., Park, Y. W., Baba, K., & Hayashi, T. (2008). Biosafety assessment of transgenic poplars overexpressing xyloglucanase (AaXEG2) prior to field trials. Journal of Wood Science, 54, 408-413.

The authors performed biosafety assessments of transgenic poplars prior to field trials.

The Japanese researchers produced transgenic poplars that could grow quickly with high cellulose content by over-expressing an enzyme from another species. The expression the enzyme in the transgenic poplars increased the cellulose content and density of the stem. The leaves were visibly greener, thicker, and smaller than those of the wild-type (non transgenic) plant.

The transgenic poplars are expected to be effective as a wood resource for pulp and paper materials because of their high cellulose content and density.

Allelopathic tests (a type of test to determine if one plant has a detrimental or harmful effect on another) showed that the transgenic poplars do not produce harmful substances. Based on all the biosafety assessments and the scientific literature on poplar species, the authors came to the conclusion that transgenic poplars probably do not disturb the biological diversity of the surrounding environment, even when they are submitted to field trials.

Keese, P. (2008). Risks from GMOs due to horizontal gene transfer. Environmental Biosafety Research, 7, 123-149.

The authors concluded that due to the low frequency of horizontal gene transfer (HGT – transfer of genes from one organism to another) and the limited chance of providing a selective advantage to the recipient organism, HGT from GM plants poses negligible risks to human health or the environment.

The genome of almost every organism reveals the footprint of many ancient HGT events. Most commonly, HGT involves the transmission of genes on viruses or mobile genetic elements (a type of DNA that can move around within the genome). HGT first became an issue of public concern in the 1970s through the natural spread of antibiotic resistance genes amongst pathogenic bacteria, and more recently with commercial production of genetically modified (GM) crops. However, the frequency of HGT from plants to other organisms is extremely low. In most cases the occurrence of HGT from GM crops to other organisms is expected to be lower than what occurs in nature.


Kogel, K. H., Voll, L. M., Schäfer, P., Jansen, C., Wu, Y., Langen, G., Imani, J., Hofmann, J., Schmiedl, A., Sonnewald, S., von Wettstein, D., Cook, R. J., & Sonnewald, U. (2010). Transcriptome and metabolome profiling of field-grown transgenic barley lack induced differences but show cultivar-specific variances. Proceedings of the National Academy of Sciences of the USA, 107, 6198-6203.

The aim of the present study was to assess possible adverse effects of transgene expression in leaves of field-grown barley relative to the influence of genetic background and the effect of plant interaction with arbuscular mycorrhizal fungi (these are fungi on roots that help plants capture nutrients from the soil). The researchers conducted a profiling study that evaluated the products (or metabolites) of genes. This study was conducted for wild-type (i.e. non-GM) and GM barley. These techniques are designed to systematically study the unique chemical fingerprints that genes leave behind. That is, they study what is expressed by different genes. Although technical in nature, the main conclusions from this study were two-fold. Firstly, the results confirmed that differences between cultivars greatly exceed effects caused by transgene expression. Secondly, the impact of even a low number of naturally occurring genes was stronger than that from transgenes.


Batista, R., Saibo, N., Lourenço, T., & Oliveira, M. M. (2008). Microarray analyses reveal that plant mutagenesis may induce more transcriptomic changes than transgene insertion. Proceedings of the National Academy of Sciences of the USA, 105, 3640-3645

This study compares genetic changes in GM plants with those that have undergone mutagenesis. Mutagenesis is an accepted process commonly used in crop breeding by which the genetic information of a plant (for example) is changed, either in nature or experimentally by the use of chemicals or radiation and it is a commonly used breeding tool in agriculture. Controversy regarding GM plants and their potential impact on human health contrasts with the tacit acceptance of other plants that were also modified, but not considered as GM products (e.g., varieties raised through conventional breeding such as mutagenesis). The authors asked the question ‘should mutagenised plants be treated differently from transgenics?’

The authors evaluated the expression of genes occurring during rice improvement through transgenesis versus mutation breeding. They found that the improvement of a plant variety through the acquisition of a new desired trait, using either mutagenesis or transgenesis, may cause stress and lead to an altered expression of untargeted genes. In all of the cases studied, the observed alteration was more extensive in mutagenized than in transgenic (i.e. GM) plants. They propose that the safety assessment of improved plant varieties should be carried out on a case-by-case basis and not simply restricted to foods obtained through genetic engineering.

Use of transgenic plants

Brookes, G., & Barfoot, P. (2008). Global impact of biotech crops: Environmental effects, 1996-2008. AgBioForum, 13, 1: Article 6.

This article, published in 2010 presents the findings of research into the global economic and environmental impact of GM crops since their commercial introduction in 1996. It focuses on the impact of changes in pesticide use and greenhouse gas emissions arising from the use of biotech crops. The technology has reduced pesticide spraying by 352 million kg (-8.4%) and, as a result, decreased the environmental impact associated with herbicide and insecticide use on these crops (as measured by the indicator the environmental impact quotient) by 16.3%. The technology has also significantly reduced the release of greenhouse gas emissions from this cropping area, which, in 2008, was equivalent to removing 6.9 million cars from the roads.


Harfouche, A., Meilan, R., Altman, A. (2010). Tree genetic engineering and applications to sustainable forestry and biomass production. Trends in Biotechnology, 29 (1), 9-17.

This paper from authors in Italy, the USA and Israel reviews genetic modification research on forestry trees. The current status of tree genetic engineering research is reviewed, including the different methodologies for gene transfer. Traits can now be introduced and expressed efficiently; examples include biotic and abiotic stress tolerance, improved wood properties, root formation and phytoremediation. In particular, drought, temperature and salinity tolerance were seen as key technologies to re-forest marginally arid areas. In the United States, 52 transgenic tree field trials had been completed, while for Europe there were 32 such trials. Other forestry-species trials mentioned were located in Indonesia, China, South Africa, Brazil, Chile, Japan and New Zealand (Scion). The authors conclude that to move this technology forward, any environmental concerns must be appropriately addressed through extensive field testing of GM trees (Table 1 and Table 2) and review of the safety data submitted to the appropriate governmental agencies before deregulation and large-scale use.The authors note that despite 114 million hectares of farmland across the world (in 2007) being planted with genetically modified (GM) crops, in Europe, the cultivation of these crops remains both limited and controversial. Indeed, scientific and policy debates in the European Union (EU) have rarely focused on the agronomic aspects of GM crops and economic impacts for EU farmers. Currently, the only GM crop authorized for commercial cultivation in the EU is a GM corn resistant to corn borer by virtue of the transgenic expression of a gene encoding Bacillus thuringiensis (Bt) toxin. Spain now has over nine years of experience in commercial cultivation of this type of GM corn.

Manuel Gómez-Barbero, M., Berbel, J., & Rodríguez-Cerezo, E. (2008). Correspondence: Bt corn in Spain—the performance of the EU’s first GM crop. Nature Biotechnology, 26, 384-386

The authors note that despite 114 million hectares of farmland across the world (in 2007) being planted with genetically modified (GM) crops, in Europe, the cultivation of these crops remains both limited and controversial. Indeed, scientific and policy debates in the European Union (EU) have rarely focused on the agronomic aspects of GM crops and economic impacts for EU farmers. Currently, the only GM crop authorized for commercial cultivation in the EU is a GM corn resistant to corn borer by virtue of the transgenic expression of a gene encoding Bacillus thuringiensis (Bt) toxin. Spain now has over nine years of experience in commercial cultivation of this type of GM corn.

Survey results show that farmers adopting Bt corn experienced higher average yields than conventional corn growers over the three growing seasons studied (2002–2004). These higher yields were, however, statistically significant for only one of the three provinces studied (a yield increase of 1,110 kg/hectare or 11.8% over conventional corn). The advantage in yields for GM corn was quite variable. The use of insecticide was lower on the GM crops but the cost of seed was higher than for conventional crops.  

Raney, T. (2006). Economic impact of transgenic crops in developing countries. Current Opinion in Biotechnology, 17, 174-178.

This paper is a review of the economic impacts of transgenic crops in developing countries. Transgenic crops are being adopted rapidly at the global level, but only a few developing countries are growing them in significant quantities. Why are these crops so successful in some countries but not in others? Farm level profitability ultimately determines whether farmers adopt and retain a new technology, but this depends on much more than technical performance. Recent economic studies in developing countries find positive, but highly variable, economic returns to adopting transgenic crops. These studies confirm that institutional factors such as national agricultural research capacity, environmental and food safety regulations, intellectual property rights and agricultural input markets matter at least as much as the technology itself in determining the level and distribution of economic benefits.

Ecological and social impacts from GM Trials  

Halpin, C. (2007). Ecological impacts of trees with modified lignin. Tree Genetics & Genomes, 3, 101-110

Few experiments have yet been performed to explore the potential ecological impacts of genetic modification in long-lifespan species such as trees. In this paper, the authors review the available data on GM trees with modified lignin focussing on the results of the first long-term field trials of such trees.

These trials evaluated poplars expressing transgenes which affect lignin biosynthesis, with the aim of producing trees that have improved pulping characteristics. The trees were grown for 4 years at two sites in France and England, and their ecological impacts and agronomic performance were assessed.

Modifications to lignin in the poplars were maintained over the 4 years of the trial. The trees remained healthy throughout and growth was normal. The lignin modifications had no adverse biological or ecological impacts.

Interactions with leaf-feeding insects, microbial pathogens and soil organisms were unaltered although the short-term decomposition of transgenic roots was slightly enhanced. Investigation of the ecological impacts of the GM trees was curtailed by the early termination of the field trial when it was attacked and largely destroyed by anti-GM protestors. Further work on the decomposition of GM plant materials with modified lignin, was continued with transgenic tobacco lines.

Fenning, T. M., Walter, C., & Gartland, K. M. A. (2008). Forest biotech and climate change. Nature Biotechnology, 26, 615 – 617

This correspondence argues that forest biotechnology has a potential leading role in climate change mitigation.

It is now clear that the rise in greenhouse gases caused by human activities is altering global climate, with larger effects very likely in the near future. Carbon dioxide (CO2) levels in the atmosphere have risen from 280 parts per million (ppm) in 1750 to nearly 400 ppm today, with 30% of this rise having been attributed to land use changes, mainly deforestation.

Forests alone can provide 30–60% of the total mitigation capacity needed for reducing the anticipated rise in atmospheric carbon over the next 50 years, yet even this does not fully take into account what might be achieved with the application of forest biotech.

Feasibility studies have shown that it is possible to replace much of the current dependence on fossil fuels with biofuels, but what is lacking is a precise mechanism for achieving this in a way that is compatible with other environmental and carbon mitigation objectives. Trees offer a solution to the risks inherent in devoting food crops to biofuel production because they provide potentially higher calorific values for biofuel production than agricultural crops: trees not only can achieve a lignocellulosics energy conversion factor of 16 (compared with 1–1.5 for corn and 8–10 for sugarcane), but also can be grown on marginal agricultural land, reducing competition for space with food crops.

An overarching strategy for the management and conservation of the world's forests is needed. Even a modest harvest reduction from natural forests will impose a pinch on global wood supply. Plantations and forest biotech (with more productive tree species) have the potential to solve this dilemma and so are crucial to the twin environmental objectives of forest conservation and climate stabilisation.

Part of the problem is that despite the absence of data suggesting that transgenic trees per se pose any special risk to the environment (field tests with genetically modified Pinus radiata in New Zealand, poplars in Germany and silver birch in Finland have shown no negative effects on wildlife or microorganisms) commercial deployments will probably remain controversial. Notwithstanding ideological objections to its commercial deployment, the importance of transgenic technology as a tool in forest research cannot be emphasized enough. In particular, it allows questions of functional genetics to be probed directly, which is especially important in relation to environmentally sensitive traits, the regulation of which are critical determinants of tree survival and are likely to be heavily influenced by climate change.

Increasing plantation productivity will be most beneficial if linked to other requirements such as improved burn characteristics, biofuel production or chemical extraction using biorefineries.

Paine, J., Shipton, C. A., Chaggar, S., Howells, R. M., Kennedy, M. J., Vernon, G., Wright, S. Y., Hinchliffe, E., Adams, J. L., Silverstone, A. L., & Drake, R. (2005). Improving the nutritional value of Golden Rice through increased pro-vitamin A content. Nature Biotechnology, 23, 482-487.

'Golden Rice' is a variety of rice genetically engineered to produce beta-carotene (pro-vitamin A) to help combat vitamin A deficiency. It has been predicted that its contribution to alleviating vitamin A deficiency would be substantially improved through even higher beta-carotene content. In Asia, Vitamin A deficiency is associated with the poverty-related predominant consumption of rice. This deficiency can result in permanent blindness and increase the severity of infectious diseases.

The authors hypothesized that the daffodil gene in Golden Rice (one of the two genes used to develop Golden Rice), was the limiting step in beta-carotene accumulation. Through systematic testing of other plant genes, they identified one from maize that substantially increased carotenoid accumulation. They went on to develop 'Golden Rice 2' introducing this maize gene. There was a large increase in total carotenoids of up to 23-fold compared to the original Golden Rice and a preferential accumulation of beta-carotene. This has important health implications for millions of people in Asian countries.

Sedjo, R. A. (2006). Toward commercialization of genetically engineered forests: economic and social considerations. Washington, DC, USA: Resources for the Future.

Anticipation of a biotechnology revolution has led to high expectations. However, one area that has been slow to develop is that of tree biotechnology, particularly genetically engineered (GE), or transgenic, trees designed for the production of wood for lumber, paper, and other industrial purposes. The question has been raised as to the adequacy of financial returns in forestry. Although the economic viability of transgenic trees has not yet been adequately demonstrated in the market, this analysis suggests the likelihood of relatively widespread deployment of transgenic trees in the intermediate future, perhaps within a decade or two. It is clear from much of the analysis that GE trees have the potential to provide substantial financial and economic returns under a variety of conditions. This paper examines the nature of financial investment costs as well as some of the differences in investing between long-lived tree products and annual agricultural crops. It identifies and examines the major impediments—economic and other—to the widespread commercial application of GE trees.