Plant Biotechnology Journal (2014) 12, pp. 277–285

doi: 10.1111/pbi.12176

Review article

Translational research: from pot to plot Hilde Nelissen1,2, Maurice Moloney3 and Dirk Inz
e1,2,* 1

Department of Plant Systems Biology, VIB, Gent, Belgium

2

Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium

3

Department of Plant Biology and Crop Sciences, Rothamsted Research, Harpenden, Hertfordshire, UK

Received 14 November 2013; revised 2 January 2014; accepted 27 January 2014. *Correspondence (Tel +32 9 331 38 00; fax +32 9 331 38 09; email [email protected])

Keywords: translational research, crops, field trials, plant biotechnology.

Summary Plant molecular biology has been the key driver to elucidate molecular pathways underlying plant growth, development and stress responses during the past decades. Although this has led to a plethora of available data, the translation to crop improvement is lagging behind. Here, we argue that plant scientists should become more involved in converting basic knowledge into applications in crops to sustainably support food security and agriculture. As the translatability from model species to crops is rather poor, this kind of translational research requires diligence and a thorough knowledge of the investigated trait in the crop. In addition, the robustness of a trait depends on the genotype and environmental conditions, demanding a holistic approach, which cannot always be evaluated under growth chamber and greenhouse conditions. To date, the improved resolution of many genome-wide technologies and the emerging expertise in canopy imaging, plant phenotyping and field monitoring make it very timely to move from the pathway specifics to important agronomical realizations, thus from pot to plot. Despite the availability of scientific know-how and expertise, the translation of new traits to applications using a transgene approach is in some regions of the world, such as Europe, seriously hampered by heavy and nontranslucent legislation for biotech crops. Nevertheless, progress in crop improvement will remain highly dependent on our ability to evaluate improved varieties in field conditions. Here, we plead for a network of protected sites for field trials across the different European climates to test improved biotech traits directly in crops.

Introduction Thirty years ago, the first transgenic plants were created (Caplan et al., 1983). This, at that time, revolutionary technology allowed plant scientists to make enormous progress in understanding numerous molecular processes (e.g. flowering time, light perception and stress tolerance). Today, there is overwhelming evidence that plant biotechnology can successfully improve agriculture (Harrigan et al., 2009) and will continue to play an important role in providing food security. Model plants such as Arabidopsis thaliana have played a pivotal role in elucidating basic molecular mechanisms. Whereas in terms of applications, Arabidopsis serves mainly as a model for Brassicas, the relevance of directly using Arabidopsis data for the improvement of cereals that secure the majority of our food and feed remains questionable. In addition, the gap between ‘Petri-dish research’, growth chamber experiments and even greenhouse observations, on the one hand, and field data, on the other hand, is large. Here, we express the opinion that plant scientists should become more engaged in bridging the gap between model plants and crops and in understanding the translation of laboratory observations to traits that retain their value under field conditions. Despite the promise for agronomical solutions that can be obtained by plant biotechnology, translational research will never be able to evolve without field trials with biotech crops. Unfortunately, in some parts of the world,

including Europe, the latter is seriously hampered by legislation (Masip et al., 2013).

Conservation of molecular mechanisms between plant species The degree by which the molecular mechanisms regulating various aspects of plant growth, development and stress tolerance are conserved throughout the plant kingdom can vary considerably. The molecular players involved in the cellular ‘core machinery’, such as protein translation and the cell cycle, tend to be maintained amongst eukaryotes (Goldman et al., 2010; Harashima et al., 2013; Koonin et al., 2004; de Lichtenberg et al., 2007). For example, the networks of proteins that regulate the different phases of the mitotic cell cycle appear to be highly conserved throughout eukaryotic evolution (Cross et al., 2011; Harashima et al., 2013; de Lichtenberg et al., 2007). Most of the variation between species mainly lies in the size and the genomic organization of the gene families rather than in the specific molecular function of these genes (Menges et al., 2007; Nieduszynski et al., 2002; Renaudin et al., 1996). In contrast to genes encoding proteins with primary cellular functions, genes which are involved in fitness of the species tend to evolve faster. For example, it was shown that genes responding to (a)biotic stress often have diverged faster in their expression levels, as compared to genes responsive to intrinsic cues such as developmental

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278 Hilde Nelissen et al. programmes, or which are part of macromolecular complexes. The gene balance hypothesis could explain this difference in expression divergence, as genes in internal responses are often involved in more complex regulatory networks compared with the more simple cascade network, to which the external response genes belong (De Smet and Van de Peer, 2012). This is also reflected by the level of chemical diversity, in which essential pathways, such as the shikimate pathway, show lower divergence compared with the less essential phenyl-propanoid pathways (Tohge et al., 2013). However, more recently, the awareness is growing that mere conservation of molecular players is not sufficient to translate observations and knowledge from one species to another. Despite the high conservation of the core cell cycle machinery amongst eukaryotes, the identity and timing of the periodically expressed genes differ substantially between different organisms (Arabidopsis, budding yeast, fission yeast and humans), suggesting that specific layers of regulation, both transcriptional and post-translational, have evolved, resulting in the assembly of similar, but not identical molecular machineries (Jensen et al., 2006; Nowack et al., 2012). At best, one can state that research in model systems allows to define the ‘gene space’ involved in a given biological problem, but that regulation and wiring of the network can vary considerably between different species. A nice example is the recent demonstration that mouse and human immune cells respond very differently to toxins and trauma (Seok et al., 2013). In plants, the photoperiodic CONSTANS-FLOWERING LOCUS T (CO-FT) signalling module seems evolutionary conserved; however, a critical role in flowering was proven only for FT in many taxa, and CO homologs were not always able to regulate FT. Indeed, divergence in the transcriptional and posttranslational regulation of FT loci results in considerable variation in FT homolog copy number and in its integration of intrinsic signals and environmental cues (Ballerini and Kramer, 2011). This results in distinct FT regulatory mechanisms, for example, in rice, a facultative short-day plant, in Arabidopsis, a long-day plant (Yanovsky and Kay, 2003) and in sugar beet (Beta vulgaris), a biennial requiring vernalization (Pin et al., 2010). Above-described examples clearly show that there is a lot of value in using model systems to unravel molecular pathways, but that researchers need to be highly vigilant upon translation into applications in crops. All this has led us to conclude that to transfer knowledge between species, it is of utmost importance to also characterize the usually complex processes such as growth, stress tolerance and yield, directly in the crop of interest.

State-of-the-art technologies facilitate research on crop species An intermediate step could be taken by studying model species which are more closely related to target crops and which might be easier to cultivate under laboratory conditions (Lata et al. (2013); The International Brachypodium Initiative, 2010). As such, Brachypodium has been proposed as a model for wheat, and Setaria has been proposed as a model for C4 crops such as maize and sorghum. Model plants are often chosen for their small size and their relative short life cycle, which might not pose an immediate advantage compared with rice, barley and wheat, whereas working directly on crops such as maize requires considerably more space. Although a rather large community opted to study Brachypodium, it took about a decade to get a fully operational toolbox (Mur et al., 2011) including transformation (Alves et al.,

2009). The implementation of new models might also result in a scattering of the scientific landscape and funding opportunities. In addition, the step from these models to the actual crops might be smaller, but their relevance for field crops and cereals is also questionable and translational research directly in the crop of interest will still be required. Although the necessity to perform research directly in crops is emerging, this is far from being evident. Some economically important crops are polyploids, and their genomes are huge (Morrell et al., 2012; Paterson et al., 2005), even consisting of a common pan-genome and a dispensable genome, which varies considerably between individuals from the same species. Besides transposable elements, the dispensable genome is thought to consist of genes which possess the ability to regulate or modify the pan-genome and can consist of about 50% of the genome, resulting in considerable variation between individuals of one species (Morgante et al., 2007). All these factors result in a more troublesome sequencing and annotation of these genomes, making the genetic information less accessible for functional genomics, mapping, mutational screens, etc. However, the inherent presence of transposons also offers advantages, because it offers a great natural source of genetic variation (Zerjal et al., 2012). For example, in maize, the PrOject Portal for corn (POPcorn) stated to contain 6500 Mu insertions and 2351 Ac/ Ds insertions in 2011 (Cannon et al., 2011), but this number is steadily increasing and complemented by other resources (Till et al., 2004; Williams-Carrier et al., 2010). For barley, European germplasm is kept in 35 gene banks, including the Barley Core Collection of 1126 accessions, comprising in total more than 135,000 accessions (Enneking et al., 2002). Another drawback of working in crops has been their higher degree of recalcitrance to transformation. Certainly, the floral-dip transformation technique of Arabidopsis (Clough and Bent, 1998) facilitated research, but today, relatively efficient transformation protocols have been worked out for most crops such as maize (Frame et al., 2002), rice (Giri and Laxmi, 2000) and several cereals (Harwood, 2012). Versatile, recombination-based vector systems specific for cereal transformation are now available (Karimi et al., 2013). In addition, transient activation of prolific cell regeneration by ectopically expressing one AP2/ERF transcription factor, BABY BOOM, was used to efficiently generate transgenic plants from species otherwise recalcitrant to Agrobacterium-mediated transformation (Heidmann et al., 2011). Indeed, we have now reached the moment in which some of the disadvantages of working with crops can be overcome or even turned into an advantage. Comparative genomics tools such as PLAZA (Van Bel et al., 2012) and Gramene (Youens-Clark et al., 2011) are being developed to identify orthologs and conserved gene families or to perform enrichment studies even in crops with a lesser annotated genome. The information in these databases is increasing rapidly due to the fast development of different sequencing technologies, which will give rise to data on genome, ORFeome, spliceome, transcriptome, etc. for many distinct genotypes per species. It will be a great challenge for bioinformaticians to tackle and make this plethora of data searchable and understandable, but it will resolve some issues regarding the complexity of crop genomes. Besides the improvement of sequencing, also the sensitivity and resolution of technologies, such as mass spectrometry and microscopy, are steadily increasing, allowing a more versatile use. Not only can many crops now be transformed, but also techniques for sitespecific mutagenesis and DNA insertion have been shown to

ª 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd, Plant Biotechnology Journal, 12, 277–285

Translational research: from pot to plot 279 work in crops: zinc-finger nucleases (Shukla et al., 2009), transcription activator-like effector nucleases (TALEN) (Li et al., 2012; Wendt et al., 2013) and even the CRISPR-associated singleguide RNA system (Cas9/sgRNA) (Jiang et al., 2013; Upadhyay et al., 2013). The functional analysis of (trans)genes will be even more facilitated with automated phenotyping platforms which are being optimized for crop species as well (Berger et al., 2012; Dhondt et al., 2013). All of these emerging technologies alleviate some of the restrictions that previously limited direct research in crops and even show that the simultaneous study of model and crop plants can provide complementary data, rendering a more holistic view on molecular mechanisms. An example of the complementarity between a model system and crops comes from plants overexpressing the rate-limiting gibberellic acid (GA) biosynthetic enzyme, GA20-oxidase, which results in increased leaf size, both in Arabidopsis and maize. It was first shown in Arabidopsis that the observed increased leaf size was due to an increase in both cell expansion and cell number (Gonzalez et al., 2010). However, due to the size of the maize leaf and the linear organization of its growth processes, enriched portions of dividing and expanding tissues for technologies requiring high input levels (Nelissen et al., 2013) could be obtained. In this way, measuring hormone levels with high resolution throughout the complete growth zone of the

maize leaf revealed that the accumulation of bioactive GAs at the transition from cell division to cell expansion was responsible for the determination of the number of cells (Nelissen et al., 2012), a mechanism that could not have been elucidated solely using the Arabidopsis leaf. This exemplifies that crop research can increase the general understanding of the mode of action, needed to understand the process of interest and, as such, to come to innovative strategies improving the desired trait (Figure 1).

The multifaceted and complex nature of translational research Whether gene identification and mode of action studies occur in model plants or directly in crops, most researchers opt for approaches that yield the highest probability to observe clear phenotypes shedding light on the actual protein function, especially when high-throughput screens are applied. For this reason, strong, constitutive promoters such as the cauliflower mosaic virus 35S promoter are routinely used for functional analysis, and the number of peer-reviewed papers using this approach is too numerous to be cited here. However, translational research also involves the design of innovative ways to use the function of a yield-enhancing or stress tolerance gene in the crop without altering additional processes or introducing undesirable

Figure 1 Overview of the different steps in plant biotech research towards agricultural applications. A good understanding of the function (mode of action) of identified key genes (gene discovery) involved in yield enhancement or stress tolerance is necessary to conceive intelligent ways to specifically modify (through chimeric gene constructs) crop plants to obtain improved traits. These studies can be performed in a model plant or directly in the crop. In a next step, the robustness of the trait under different environmental conditions will be evaluated in the greenhouse, climate houses or directly in the field. The traits, which result in a yield increase under field conditions, will be used for the development of commercial varieties. All different steps in this process are under continuous innovation so that the scientific community is now ready to start translating the knowledge obtained by plant biotechnology into applications. ª 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd, Plant Biotechnology Journal, 12, 277–285

280 Hilde Nelissen et al. traits. One way to do this is to fine-tune the expression of the identified gene in time or space, allowing the gene to actually function when and where its activity is required. This is usually achieved by creating chimeric gene constructs in which the gene of interest is expressed under the control of a specific promoter, rendering its expression organ, tissue, developmentally or environmentally dependent. The importance of organ- and tissuespecific promoters as a valuable tool for agricultural applications is currently becoming evident (Jeong et al., 2010; Jung et al., 2012; Yang et al., 2013), and the identification and validation of specific promoters will create value for the engineering of chimeric gene constructs and the stacking thereof. The rationale behind the decision in which combination of promoter and gene to include in the chimeric constructs relies heavily on a good understanding of the mode of action of both components, and the success of such a chimeric construct to improve a certain trait will feed back into the understanding of the given trait (Figure 1). Indeed some traits can be changed by altering a single gene, but many traits of agricultural interest, such as yield and stress tolerance, are considered to be complex, as they are influenced by many genes (multigenic) as well as environmental factors (Womack et al., 2012). Such complex traits are usually more difficult to breed for or to engineer (Parry and Hawkesford, 2012), as they often encompass independent genetic pathways that might interact and that show a dependence on environment and plant physiology (Womack et al., 2012). In addition, these trait components can often be split up into different subtraits. For example, ‘seed yield’ can be described by seed size, seed number, number of seeds per pod or ear, thousand kernel weight, seed quality, oil content, etc. (Diepenbrock, 2000). Some of these subtraits (for instance, kernel weight) are more genetically determined and thus more stable as compared to other subtraits (such as seed number) (Borr
as et al., 2003), indicating that some individual components might be easier to engineer than others. In the greenhouse, yield is typically determined as yield per plant, while a farmer is more interested in yield per area. For example, an already complex trait, such as seed yield, depends on a variable like planting density (Diepenbrock, 2000), which is not generally encountered in the greenhouse. This is a good example of how difficult it can be to extrapolate the multifaceted and complex nature of crop yield from laboratory and greenhouse studies to the likely outcome in farm cultivation.

Canopy imaging and precision agriculture lead the way to the field Besides the realization that processes and efficacious genes identified in model plants are poorly, if at all, translated into beneficial effects on crops, an awareness of the agricultural constrains that limit crop productivity is emerging. The success of transgene strategies will largely depend not only on the effect but also on the penetrance of a given trait across environments and germplasms (Castiglioni et al., 2008). A striking example is the vast amount of literature on the molecular responses of plants to drought, including field trials showing that certain genes improve the survival of plants in water-limiting conditions (reviewed by Deikman et al., 2012). However, so far, no transgenic commercial biotech varieties based on that knowledge have been released, with the notable exception of DroughtGard, a maize biotech variety in which a bacterial cold-shock protein, cspB, is expressed, resulting in a yield advantage under water-limiting conditions (Castiglioni et al., 2008; Harrigan et al., 2009). Understanding

why there is such a low translatability is of key importance for the future development of improved crop traits. One main approach to solve this is to study molecular responses directly in crops preferably in conditions that are as close as possible to the field. The major hurdles to translate laboratory-identified traits to actual improved varieties are the difficulty to approximate field conditions in the greenhouse and to accurately and relevantly phenotype in a high-throughput way in the field (Tuberosa, 2012). In an academic setting, phenotyping is usually performed in standardized conditions providing the maximal reproducibility, preferentially in growth chambers or greenhouses in which temperature, light and humidity are tightly regulated. However, field conditions reflect a combination of fluctuating environmental conditions or stresses and variation in soil biophysics within the test plot with a planting density that differs from plants grown in pots in the greenhouse (Tuberosa, 2012). Recently, companies have started to invest in state-of-the-art greenhouses that represent simultaneously different world climates by controlling light, temperature, humidity and fertigation in mirror-walled, shadow-less growth chambers (http://www.syngenta-us.com/ News_releases/news.aspx?id=174028). However, these tailormade solutions, which can be considered as hybrids between the greenhouse and the field (and referred to as climate house in Figure 1), are still far from the reach of many academic institutes and small- and medium-sized enterprises. This intrinsic difficulty to mimic the ever-fluctuating field and environmental conditions in a greenhouse makes the translational step from the greenhouse to the field of utmost importance to estimate what remains of a greenhouse-identified trait in authentic farming conditions (Figure 1). Recently, technologies to facilitate the observation and monitoring of different environmental, biophysical and physiological conditions in the field have been emerging. The latest developments in phenotyping crops under field conditions were extensively reviewed (Dhondt et al., 2013; Fiorani and Schurr, 2013; Masuka et al., 2012; Tuberosa, 2012), so we will simply highlight some recent innovative developments. The canopy can be monitored using visible, fluorescent, or even hyperspectral imaging or nonoptical methods such as teraherz radiation or microwave (Fiorani and Schurr, 2013); sap-flow sensors can provide insights into water transport, and the monitoring of field soil quality determines variation in soil water content and nutrient availability (Busemeyer et al., 2013; De Swaef et al., 2013; Jones, 2004; Masuka et al., 2012). The detailed plotting of the environmental conditions with high temporal and spatial resolution (also referred to as precision agriculture) allows to locally overcome suboptimal conditions by adding more water or nitrogen to parts of the plot where shortage occurs. In addition, technologies were developed to precisely manage and map variations in the environment using changing atmospheric gasses, temperature, sensor-based rain shelters, etc. (Betzelberger et al., 2012; Scudiero et al., 2012). The development of Farm Platform Centers, such as the Rothamsted’s North Wyke site (www. rothamsted.ac.uk/farm-platform-national-capability), offers the possibility of applying a systems biology approach at field and farm scale, through the continuous acquisition of data on all major inputs and outputs from farm-scale experiments. Data on the dynamics of nutrients, water and gaseous emissions in the field should allow scientists to correlate them with phenotypic changes and particular responses of the genome and gene expression to a dynamic environment (Yang et al., 2011). The combination of precision agriculture and the ability to mimic

ª 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd, Plant Biotechnology Journal, 12, 277–285

Translational research: from pot to plot 281 adverse conditions even in field trials opens perspectives to perform large-scale (stress) field trials, so new varieties can be evaluated for their yield potential under changing environmental conditions, such as drought, increasing CO2 or temperature by global warming (Mir et al., 2012). Recently, a large-scale statistical modelling study showed the effects of naturally occurring field conditions on changes in the transcriptome in rice, using a large amount of microarrays and meteorological data collected from rice plants grown during two growing seasons, compared with plants grown in growth chambers. Surprisingly, no more than 17 parameters could account for the majority of expression changes, and the resulting models might allow to predict how a set of environmental conditions can influence the transcriptome and eventually the phenotype (Nagano et al., 2012). This, together with the above-mentioned emerging technologies, preludes spectacular times ahead for plant research and also provides great promise to increase the success rate to translate greenhouse traits into commercially viable applications.

Lost in translation? Despite the fact that the know-how and toolbox are available, it is important to realize that translational research comes at a cost and that some reservations need to be addressed by the appropriate authorities. Often the limiting factor to translate exciting basic findings to agricultural applications is not the lack of motivation from the researchers, but rather infrastructural or budgetary restraints. Translational research typically requires at least two species, the model and the crop, which often differ substantially in terms of growth conditions, necessitating compartmentalized greenhouses, each with their specific requirements. On top of that, working with crops requires more greenhouse space, which should often be equipped with higher temperatures and more lights, raising the energy costs. In addition, the generation time of many crops is substantially longer than that of model species, making the current funding schemes of 3 to 5 years rather restrictive to perform translational research. So far, these increased costs, need for greenhouse space and extended generation time might limit translational research to institutes with substantial in-house funding for infrastructure or to extend grants from public funding entities. Therefore, we plea that governments and funding agencies install specific funding mechanisms adjusted to the needs of plant translational research, just as they initiated a decade ago for biomedical translational research (Kaitin, 2012; Woolf, 2008). However, as the name ‘translational research’ implies, basic knowledge, often obtained in model species, is the primary requirement to allow translation of data into applications. Moreover, major discoveries are still made in Arabidopsis, and some studies in models can be efficiently and directly be translated into applications, such as reverse breeding (Wijnker and Schnittger, 2013). Thus, a healthy balance should be maintained between funding basic research in model systems and adjusted funding specifically for translational research: one should never be at the expense of the other. Similarly, scientific evaluation should be adjusted to translational research. Researchers and institutes are being evaluated, at least in part, by their scientific output based on the number and the impact of their publications. Crop research is slow and often less mechanistic, and translational research is inoculated on previously published data, while high-impact journals typically seek for studies that provide detailed mechanistic insights into a

novel process. So, not only adjusted funding opportunities, but also alternative evaluation schemes are necessary to stimulate translational research. In addition, students should be challenged to critically address translational research as it represents a novel discipline in plant biology. Today, education in plant biotechnology and related fields mainly focusses on the molecular biology of Arabidopsis without much emphasis on putative applications. We should stimulate the awareness of our future scientists with respect to translating findings into applications by implementing more aspects of crop physiology and agricultural needs into the academic programmes. So, although technologically science is ready to move plant translational research forward, this should still be enabled more by appropriate funding and publication strategies and by approaching the biological question from a different and original angle.

Science is ready for field trials, but will politics follow? The increasing demand for plant-derived products for food, feed, bioenergy, clothing and other applications enforces the need to increase plant yield and yield stability in the coming decades. This goal can only be achieved if different disciplines (biophysics, chemistry, engineering, plant physiology, plant breeding, plant biotechnology, etc.) can contribute to the maximum of their potential. Plant biotechnology can offer great opportunities mainly by combining distinct molecular processes to influence multigenic traits such as growth, yield and disease resistance (Davies et al., 2009). The availability of a well-equipped toolbox for biotechnological research in many crops and the state-of-theart technologies, which are currently available for field observations as well as precise monitoring of environmental conditions, enable a more efficient translation of basic knowledge to applications. However, an additional hurdle to take when assessing whether a putative biotech trait identified in laboratory conditions indeed can result in a higher yield under field conditions is the very tough legislation to establish a biotech field trial imposed by some regions of the world, posing a heavy administrative and protective burden that can only be carried out by a few large research institutes. One major distinction between biotech crops and more ‘conventional’ nontransgenic varieties is the compositional equivalence studies which are uniquely required for biotech crops. Over the years, these studies have expanded, thus increasing their costs up to US $ 100 million per study, making crop improvement through plant biotechnology difficult for public researchers and developing countries due to exorbitant costs. However, it became clear from all transgenic events evaluated in the USA and Japan that biotech crops (spanning more than 10 crops and 7 different traits) can be considered to be compositionally equivalent to their nontransgenic counterparts (Herman and Price, 2013). Also, the European Food Safety Authority (EFSA) performs comparative analyses of compositional, phenotypic and agronomic characteristics of biotech crops grown in Europe (EFSA Panel on Genetically Modified Organisms (GMO), 2012). So far, all these studies, 1783 over the past 10 years, indicated no significant difference between biotech and conventional varieties in composition, digestibility or animal health or performance, supporting their substantial equivalence (Nicolia et al., 2014). This argues strongly that compositional studies required for biotech crops are completely disproportionate to any possible risk and that it would be more appropriate to assess the

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282 Hilde Nelissen et al. effect of the introduced/novel trait(s), independent of the methodology used to obtain this (these) trait(s) (biotech versus nontransgenic) (Ammann, 2014; Herman and Price, 2013). In addition, the complex legislation regarding the import or cultivation of biotech crops in Europe and some other parts of the world is exacerbated by unpredictable decision-making and unforeseen delays, not based on scientific evidence, in the approval or rejection process (Raybould and Poppy, 2012). To fully capture the potential of plant biotechnology for crop

improvement, for both academia and agro-biotech companies, there is an urgent need to ease the legislation and reduce the timing towards field trials and product approvals, in proportion to the minimal risks that biotech crops pose. Traditionally, Europe has a major stake in crop improvement with world-leading companies that use plant biotechnology, but the need to perform field trials and the lengthy and unpredictable legislation drive these companies to other areas in the world, taking with them jobs and economic growth.

Figure 2 Schematic overview of the need for dedicated field trials in Europe, distributed over different climatological regions. Some member states already have dedicated field trial sites assigned (red flag), while other countries perform ad hoc field trials (blue flags). However, this opinion paper launched the idea to formalize these field trials into dedicated field trial sites and to initiate similar initiatives in some other member states across the European Union (green flags). Furthermore, imaging technology and know-how on how to perform and measure field-related data could be standardized making comparisons across areas in Europe straight forward. In this way, scientists will be better positioned to draw conclusions regarding the translatability of traits in crops from the growth chamber to the green house and to the field. In addition, by performing field trials at several of these European sites, the position of Europe as an agricultural innovative region will be strengthened and the penetrance of transgenes under different climatological conditions will be assessed. ª 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd, Plant Biotechnology Journal, 12, 277–285

Translational research: from pot to plot 283 A first step towards a better integration of biotech crops in the European society would be to install dedicated fields across Europe, equipped with state-of-the-art imaging to monitor the growth and physiology of crops, representing different climates to test various biotech crops. The administrative hurdles to apply for such field trials should be limited, but the fields should be well protected and managed according to all safety and stewardship measures. Although field trials are currently being conducted in some European member states, with Spain as a leader, (http:// gmoinfo.jrc.ec.europa.eu/gmp_browse.aspx), other countries started to invest in dedicated infrastructure to perform field trials with biotech crops. Switzerland recently took the forefront in this by securing funding for the coming 5 years to run a permanently protected field trial site, where researchers can evaluate biotech crops without additional costs (Romeis et al., 2013). The United Kingdom has taken a similar initiative at the Rothamsted Research Institute near London, with a secure site capable of growing about three hectares of transgenic test crops. We would encourage other European member states to follow this example and implement safe harbours for biotech field trials over the different geographical and climate conditions, not only allowing cost-effective and well-protected research for biotech crops, but also opening collaborative opportunities to test the biotech crops under a range of environmental conditions (Figure 2). In addition, imaging technology and know-how on how to perform and measure field-related data could be standardized making comparisons across areas in Europe straight forward. Imagine the possibilities for Europe if we anchor this technology for which so much knowledge is at hand. . .

Acknowledgements The authors wish to thanks Valerie Frankard (Cropdesign, BASF) for critically reading and Annick Bleys for editing of the manuscript. The research in the group of Dirk Inz
e is supported by grants from Ghent University (Bijzonder Onderzoeksfonds Methusalem project no. BOF08/01M00408 and Multidisciplinary Research Partnership, Biotechnology for a Sustainable Economy no. 01MRB510W) and the Interuniversity Attraction Poles Program (IUAP P7/29 “MARS”), initiated by the Belgian State, Science Policy Office.

Conflict of interest No conflict of interests are to be declared.

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