Feral genetically modified herbicide tolerant oilseed rape from seed import spills: are concerns scientifically justified?

Agricultural weeds: the contribution of domesticated species to the origin and evolution of feral weeds

Agricultural weeds descended from domesticated ancestors, directly from crops (endoferality) and/or from crop-wild hybridization (exoferality), may have evolutionary advantages by rapidly acquiring traits pre-adapted to agricultural habitats. Understanding the role of crops on the origin and evolution of agricultural weeds is essential to develop more effective weed management programs, minimize crop losses due to weeds, and accurately assess the risks of cultivated genes escaping. In this review, we first describe relevant traits of weediness: shattering, seed dormancy, branching, early flowering and rapid growth, and their role in the feralization process. Furthermore, we discuss how the design of "super-crops" can affect weed evolution. We then searched for literature documenting cases of agricultural weeds descended from well-domesticated crops, and describe six case studies of feral weeds evolved from major crops: maize, radish, rapeseed, rice, sorghum, and sunflower. Further studies on the origin and evolution of feral weeds can improve our understanding of the physiological and genetic mechanisms underpinning the adaptation to agricultural habitats and may help to develop more effective weed-control practices and breeding better crops. © 2022 Society of Chemical Industry.

Prospects of Feral Crop De Novo Redomestication

Modern agriculture depends on a narrow variety of crop species, leaving global food and nutritional security highly vulnerable to the adverse effects of climate change and population expansion. Crop improvement using conventional and molecular breeding approaches leveraging plant genetic diversity using crop wild relatives (CWRs) has been one approach to address these issues. However, the rapid pace of the global change requires additional innovative solutions to adapt agriculture to meet global needs. Neodomestication-the rapid and targeted introduction of domestication traits using introgression or genome editing of CWRs-is being explored as a supplementary approach. These methods show promise; however, they have so far been limited in efficiency and applicability. We propose expanding the scope of neodomestication beyond truly wild CWRs to include feral crops as a source of genetic diversity for novel crop development, in this case 'redomestication'. Feral crops are plants that have escaped cultivation and evolved independently, typically adapting to their local environments. Thus, feral crops potentially contain valuable adaptive features while retaining some domestication traits. Due to their genetic proximity to crop species, feral crops may be easier targets for de novo domestication (i.e. neodomestication via genome editing techniques). In this review, we explore the potential of de novo redomestication as an application for novel crop development by genome editing of feral crops. This approach to efficiently exploit plant genetic diversity would access an underutilized reservoir of genetic diversity that could prove important in support of global food insecurity in the face of the climate change.

Assessment of genetically modified oilseed rape MON 94100 for food and feed uses, under regulation (EC) No 1829/2003 (application EFSA-GMO-NL-2020-169)

Oilseed rape MON 94100 was developed to confer tolerance to dicamba herbicide. The molecular characterisation data and bioinformatic analyses do not identify issues requiring food/feed safety assessment. None of the identified differences in the agronomic/phenotypic and compositional characteristics tested between oilseed rape MON 94100 and its conventional counterpart needs further assessment, except for the levels of carbohydrates, calcium and ADF in seeds, which do not raise nutritional and safety concerns. The GMO Panel does not identify safety concerns regarding the toxicity and allergenicity of the dicamba mono‐oxygenase (DMO) protein as expressed in oilseed rape MON 94100. The GMO Panel finds no evidence that the genetic modification impacts the overall safety of oilseed rape MON 94100. In the context of this application, the consumption of food and feed from oilseed rape MON 94100 does not represent a nutritional concern in humans and animals. The GMO Panel concludes that oilseed rape MON 94100 is as safe as the conventional counterpart and non‐GM oilseed rape reference varieties tested, and no post‐market monitoring of food/feed is considered necessary. In the case of accidental release of viable oilseed rape MON 94100 seeds into the environment, this would not raise environmental safety concerns. The post‐market environmental monitoring plan and reporting intervals are in line with the intended uses of oilseed rape MON 94100. The GMO Panel concludes that oilseed rape MON 94100 is as safe as its conventional counterpart and the tested non‐GM oilseed rape reference varieties with respect to potential effects on human and animal health and the environment.

A Review of the Unintentional Release of Feral Genetically Modified Rapeseed into the Environment

Simple Summary

With the advent of genetic engineering technology, the development and cultivation of genetically modified (GM) crops has increased. They were mainly developed for high yielding, herbicide resistance, and tolerance against different biotic and abiotic stresses. Rapeseed, also known as canola, was developed mainly for herbicide resistance and to increase the production of canola oil. Since it forms weedy, feral populations and has a proven ability to hybridize with its close relatives, it is important to manage the GM crops’ cultivation and spread, especially the rapeseed. Several studies have reported that the spread of GM rapeseed in non-GM fields and road verges is possible due to transport and agronomic practices, and it may become a weed. Hence, in this review, we summarized the cases of unintentional spread of feral GM rapeseed in the fields and road verges. In addition, we made recommendations for the effective management of feral GM and non-GM rapeseed in agricultural fields and along roads.

Abstract

Globally, the cultivation area of genetically modified (GM) crops is increasing dramatically. Despite their well-known benefits, they may also pose many risks to agriculture and the environment. Among the various GM crops, GM rapeseed (Brassica napus L.) is widely cultivated, mainly for oil production. At the same time, B. napus possesses a number of characteristics, including the ability to form feral populations and act as small-seeded weeds, and has a high potential for hybridization with other species. In this review, we provide an overview of the commercialization, approval status, and cultivation of GM rapeseed, as well as the status of the feral rapeseed populations. In addition, we highlight the case studies on the unintentional environmental release of GM rapeseed during transportation in several countries. Previous studies suggest that the main reason for the unintentional release is seed spillage during transport/importing of rapeseed in both GM rapeseed-cultivating and -non-cultivating countries. Despite the fact that incidents of unintentional release have been recorded often, there have been no reports of serious detrimental consequences. However, since rapeseed has a high potential for hybridization, the possibilities of gene flow within the genus, especially with B. rapa, are relatively significant, and considering their weedy properties, effective management methods are needed. Hence, we recommend that specific programs be used for the effective monitoring of environmental releases of GM rapeseed as well as management to avoid environmental and agricultural perturbations.

Assessment of genetically modified oilseed rape 73496 for food and feed uses, under Regulation (EC) No 1829/2003 (application EFSA-GMO-NL-2012-109)

Oilseed rape 73496 was developed to confer tolerance to the herbicidal active substance glyphosate through the expression of the glyphosate acetyltransferase protein GAT4621. The molecular characterisation data and bioinformatic analyses identify no issues requiring food/feed safety assessment. None of the identified differences between oilseed rape 73496 and its conventional counterpart in the agronomic/phenotypic endpoints tested needs further assessment. Differences identified in seed composition of oilseed rape 73496 as compared to its conventional counterpart raise no safety and nutritional concerns in the context of the scope of this application. No safety concerns are identified regarding toxicity and allergenicity of the GAT4621 protein as expressed in oilseed rape 73496. No evidence is found that the genetic modification would change the overall allergenicity of oilseed rape 73496. Based on the outcome of the comparative and nutritional assessments, the consumption of oilseed rape 73496 does not represent any nutritional concern, in the context of the scope of this application. The implementation of a post-market monitoring plan is recommended to confirm the predicted consumption data and to verify that the conditions of use are those considered during the pre-market risk assessment. In the case of accidental release of viable oilseed rape 73496 seeds into the environment, oilseed rape 73496 would not raise environmental safety concerns. The post-market environmental monitoring plan and reporting intervals are in line with the intended uses of oilseed rape 73496. The GMO Panel concludes that oilseed rape 73496, as described in this application, is as safe as its conventional counterpart and the non-genetically modified oilseed rape reference varieties tested with respect to potential effects on human and animal health and the environment.

Assessment of genetically modified oilseed rape MS11 for food and feed uses, import and processing, under Regulation (EC) No 1829/2003 (application EFSA-GMO-BE-2016-138)

Oilseed rape MS11 has been developed to confer male sterility and tolerance to glufosinate-ammonium-containing herbicides. Based on the information provided in the application and in line with the scope of application EFSA-GMO-BE-2016-138, the genetically modified organism (GMO) Panel concludes that the molecular characterisation data and bioinformatic analyses do not identify issues requiring food/feed safety assessment. None of the identified differences in the agronomic/phenotypic characteristics tested between oilseed rape MS11 and its conventional counterpart needs further assessment. No conclusions can be drawn for the compositional analysis due to the lack of an appropriate compositional data set. No toxicological or allergenicity concerns are identified for the Barnase, Barstar and PAT/bar proteins expressed in oilseed rape MS11. Owing to the incompleteness of the compositional analysis, the toxicological, allergenicity and nutritional assessment of oilseed rape MS11 cannot be completed. In the case of accidental release of viable oilseed rape MS11 seeds into the environment, oilseed rape MS11 would not raise environmental safety concerns. The post-market environmental monitoring plan and reporting intervals are in line with the scope of the application. Since oilseed rape MS11 is designed to be used only for the production of hybrid seed, it is not expected to be commercialised as a stand-alone product for food/feed uses. Thus, seeds harvested from oilseed rape MS11 are not expected to enter the food/feed chain, except accidentally. In this context, the GMO Panel notes that, oilseed rape MS11 would not pose risk to humans and animals, while the scale of environmental exposure will be substantially reduced compared to a stand-alone product.

Potential risk evaluation for unintended entry of genetically modified plant Propagating material in Europe through import of seeds and animal feed - the experience of Latvia

Significant attention has been drawn to the adventitious and technically unavoidable presence of genetically modified (GM) organisms in the food and feed imported into the European Union (EU), while the potential presence of GM seeds in material for cultivation is less studied. Here we report a study from an EU member state, Latvia, during years 2017-2018 regarding monitoring for the presence of GM seeds in certified seed and animal feed material. Eighty-two and 28 samples of seeds intended for cultivation were analyzed in 2017 and 2018, respectively. One soybean sample contained MON40-3-2 soybean seeds (0.09 ± 0.01%) and one maize sample contained MON810 maize seeds (0.08 ± 0.01%). In addition, 102 samples of feed imported from outside of the EU or produced locally were also analyzed for the presence of genetically modified organisms (GMOs) and viability of grains. One oilseed rape cake sample contained GT73 (1.04 ± 0.01%) and one soybean cake sample contained MON40-3-2 (<0.045%). One sample of declared MON40-3-2 GM soybean cake was confirmed to be positive, with MON40-3-2 content of 94.78 ± 10.01%. One soybean sample submitted by feed producer and originating from Argentina contained 54.9 ± 1.1% of MON40-3-2 and one rapeseed sample originating from Ukraine contained 5.30 ± 3.95% of GT73. Although only two seed samples contained low levels of GMOs authorized in the EU for food and feed uses, this study reinforced the need to maintain regular monitoring programs that assist farmers in their efforts to comply with the current EU GMO legislation.

Genetically modified seeds and plant propagating material in Europe: potential routes of entrance and current status

Genetically modified organisms (GMO), mainly crop plants, are increasingly grown worldwide leading to large trade volumes of living seeds and other plant material both for cultivation and for food and animal feed. Even though all the traded GMOs have been assessed for their safety with regards to human and animal health and the environment, there still are some concerns regarding the potential uncontrolled release in the environment of authorized or unauthorized GM plants. In this review, we identify the possible entrance routes of GM seeds and other propagating plant material in the EU which could be linked to unauthorized release of GMOs in the environment. In addition, we discuss the situation with GM plant cultivation in some non-EU countries in terms of potential risks for GM seed imports. The available body of information suggests that GM seeds and plant propagating material can enter the EU due to problems with labeling/traceability of GM seed lots, contamination of conventional seed lots and accidental release into the environment of grains imported for food and animal feed. Even though cases of uncontrolled release of authorized GMOs, as well as, release of unauthorized GMOs have been reported, they can be generally attributed to adventitious and technically unavoidable presence with little environmental impact. In conclusion, the probability of GM seeds and plant propagating material illegally entering the cultivation in EU is unlikely. However, specific monitoring programs need to be established and maintained to facilitate the compliance of European farmers with the current GMO legislation.

Transgene escape and persistence in an agroecosystem: the case of glyphosate-resistant Brassica rapa L. in central Argentina

Brassica rapa L. is an annual Brassicaceae species cultivated for oil and food production, whose wild form is a weed of crops worldwide. In temperate regions of South America and especially in the Argentine Pampas region, this species is widely distributed. During 2014, wild B. rapa populations that escaped control with glyphosate applications by farmers were found in this area. These plants were characterized by morphology and seed acidic profile, and all the characters agreed with B. rapa description. The dose-response assays showed that the biotypes were highly resistant to glyphosate. It was also shown that they had multiple resistance to AHAS-inhibiting herbicides. The transgenic origin of the glyphosate resistance in B. rapa biotypes was verified by an immunological test which confirmed the presence of the CP4 EPSPS protein and by an event-specific GT73 molecular marker. The persistence of the transgene in nature was confirmed for at least 4 years, in ruderal and agrestal habitats. This finding suggests that glyphosate resistance might come from GM oilseed rape crops illegally cultivated in the country or as a seed contaminant, and it implies gene flow and introgression between feral populations of GM B. napus and wild B. rapa. The persistence and spread of the resistance in agricultural environments was promoted by the high selection pressure imposed by intensive herbicide usage in the prevalent no-till farming systems.

Scientific Opinion on application EFSA-GMO-NL-2013-119 for authorisation of genetically modified glufosinate-ammonium- and glyphosate-tolerant oilseed rape MON 88302 × MS8 × RF3 and subcombinations independently of their origin, for food and feed uses, import and processing submitted in accordance with Regulation (EC) No 1829/2003 by Monsanto Company and Bayer CropScience

In this opinion, the GMO Panel assessed the three‐event stack oilseed rape (OSR) MON 88302 × MS8 × RF3 and its three subcombinations, independently of their origin. The GMO Panel has previously assessed the single events combined to produce this three‐event stack OSR and did not identify safety concerns; no new information that would modify the original conclusions was identified. The combination of the single OSR events and of the newly expressed proteins in the three‐event stack OSR does not give rise to food and feed safety and nutrition issues – based on the molecular, agronomic/phenotypic and compositional characteristics. In the case of accidental release of viable OSR MON 88302 × MS8 × RF3 seeds into the environment, the three‐event stack OSR would not raise environmental safety concerns. The GMO Panel therefore concluded that the three‐event stack OSR is as safe and as nutritious as its conventional counterpart and the tested non‐GM reference varieties in the context of the scope of this application. Since no new safety concerns were identified for the previously assessed two‐event stack OSR MS8 × RF3, the GMO Panel considered that its previous conclusions on this subcombination remain valid. For the two subcombinations MON 88302 × MS8 and MON 88302 × RF3 for which no experimental data were provided, the GMO Panel assessed the likelihood of interactions among the single events, and concluded that their different combinations would not raise safety concerns. These two subcombinations are therefore expected to be as safe as the single events, the previously assessed OSR MS8 × RF3, and OSR MON 88302 × MS8 × RF3. Since the post‐market environmental monitoring plan for the three‐event stack OSR does not include any provisions for two subcombinations not previously assessed, the GMO Panel recommended the applicant to revise the plan accordingly.

Transgenic glyphosate-resistant oilseed rape (Brassica napus) as an invasive weed in Argentina: detection, characterization, and control alternatives

The presence of glyphosate-resistant oilseed rape populations in Argentina was detected and characterized. The resistant plants were found as weeds in RR soybeans and other fields. The immunological and molecular analysis showed that the accessions presented the GT73 transgenic event. The origin of this event was uncertain, as the cultivation of transgenic oilseed rape cultivars is prohibited in Argentina. This finding might suggest that glyphosate resistance could come from unauthorized transgenic oilseed rape crops cultivated in the country or as seed contaminants in imported oilseed rape cultivars or other seed imports. Experimentation showed that there are alternative herbicides for controlling resistant Brassica napus populations in various situations and crops. AHAS-inhibiting herbicides (imazethapyr, chlorimuron and diclosulam), glufosinate, 2,4-D, fluroxypyr and saflufenacil proved to be very effective in controlling these plants. Herbicides evaluated in this research were employed by farmers in one of the fields invaded with this biotype and monitoring of this field showed no evidence of its presence in the following years.

Evolutionary and social consequences of introgression of nontransgenic herbicide resistance from rice to weedy rice in Brazil

Several studies have expressed concerns about the effects of gene flow from transgenic herbicide-resistant crops to their wild relatives, but no major problems have been observed. This review describes a case study in which what has been feared in transgenics regarding gene flow has actually changed biodiversity and people's lives. Nontransgenic imidazolinone-resistant rice (IMI-rice) cultivars increased the rice grain yield by 50% in southern Brazil. This increase was beneficial for life quality of the farmers and also improved the regional economy. However, weedy rice resistant to imidazolinone herbicides started to evolve three years after the first use of IMI-rice cultivars. Population genetic studies indicate that the herbicide-resistant weedy rice was mainly originated from gene flow from resistant cultivars and distributed by seed migration. The problems related with herbicide-resistant weedy rice increased the production costs of rice that forced farmers to sell or rent their land. Gene flow from cultivated rice to weedy rice has proven to be a large agricultural, economic, and social constraint in the use of herbicide-resistant technologies in rice. This problem must be taken into account for the development of new transgenic or nontransgenic rice technologies.

Long-Term Monitoring of Field Trial Sites with Genetically Modified Oilseed Rape (Brassica napus L.) in Saxony-Anhalt, Germany. Fifteen Years Persistence to Date but No Spatial Dispersion

Oilseed rape is known to persist in arable fields because of its ability to develop secondary seed dormancy in certain agronomic and environmental conditions. If conditions change, rapeseeds are able to germinate up to 10 years later to build volunteers in ensuing crops. Extrapolations of experimental data acted on the assumption of persistence periods for more than 20 years after last harvest of rapeseed. Genetically-modified oilseed rape-cultivated widely in Northern America since 1996-is assumed not to differ from its conventional form in this property. Here, experimental data are reported from official monitoring activities that verify these assumptions. At two former field trial sites in Saxony-Anhalt genetically-modified herbicide-resistant oilseed rape volunteers are found up to fifteen years after harvest. Nevertheless, spatial dispersion or establishment of GM plants outside of the field sites was not observed within this period.

Fixed-route monitoring and a comparative study of the occurrence of herbicide-resistant oilseed rape (Brassica napus L.) along a Japanese roadside

Previously, we conducted a roadside survey to reveal the occurrence of genetically modified (GM) oilseed rape along a Japanese roadside (Route 51). In this study, we performed successive and thorough fixed-route monitoring in 5 sections along another road (Route 23). Oilseed rape plants were detected on both sides of the road in each section between autumn 2009 and winter 2013, which included 3 flowering seasons. In four sections, more plants were found on the side of the road leading from the Yokkaichi port than on the opposite side. In the fifth section, the presence of clogged drains on the roadside, where juvenile plants concentrated, caused the opposite distribution: oilseed rape predominantly occurred along the inbound lanes (leading to the Yokkaichi port) in 2010 and 2012. Unlike in our previous survey, glyphosate- or glufosinate-resistant oilseed rape plants were abundant (>75% of analyzed plants over 3 years). Moreover, a few individuals bearing both herbicide resistance traits were also detected in some sections. The spillage of imported seeds may explain the occurrence of oilseed rape on the roadside. The abundance of herbicide-resistant oilseed rape plants may reflect the extent of contamination with GM oilseed rape seed within imports.

Occurrence of Transgenic Feral Alfalfa (Medicago sativa subsp. sativa L.) in Alfalfa Seed Production Areas in the United States

The potential environmental risks of transgene exposure are not clear for alfalfa (Medicago sativa subsp. sativa), a perennial crop that is cross-pollinated by insects. We gathered data on feral alfalfa in major alfalfa seed-production areas in the western United States to (1) evaluate evidence that feral transgenic plants spread transgenes and (2) determine environmental and agricultural production factors influencing the location of feral alfalfa, especially transgenic plants. Road verges in Fresno, California; Canyon, Idaho; and Walla Walla, Washington were surveyed in 2011 and 2012 for feral plants, and samples were tested for the CP4 EPSPS protein that conveys resistance to glyphosate. Of 4580 sites surveyed, feral plants were observed at 404 sites. Twenty-seven percent of these sites had transgenic plants. The frequency of sites having transgenic feral plants varied among our study areas. Transgenic plants were found in 32.7%, 21.4.7% and 8.3% of feral plant sites in Fresno, Canyon and Walla Walla, respectively. Spatial analysis suggested that feral populations started independently and tended to cluster in seed and hay production areas, places where seed tended to drop. Significant but low spatial auto correlation suggested that in some instances, plants colonized nearby locations. Neighboring feral plants were frequently within pollinator foraging range; however, further research is needed to confirm transgene flow. Locations of feral plant clusters were not well predicted by environmental and production variables. However, the likelihood of seed spillage during production and transport had predictive value in explaining the occurrence of transgenic feral populations. Our study confirms that genetically engineered alfalfa has dispersed into the environment, and suggests that minimizing seed spillage and eradicating feral alfalfa along road sides would be effective strategies to minimize transgene dispersal.

The presence of Bt-transgenic oilseed rape in wild mustard populations affects plant growth

The adventitious presence of transgenic plants in wild plant populations is of ecological and regulatory concern, but the consequences of adventitious presence are not well understood. Here, we introduced Bacillus thuringiensis Cry1Ac (Bt)-transgenic oilseed rape (Bt OSR, Brassica napus) with various frequencies into wild mustard (Brassica juncea) populations. We sought to better understand the adventitious presence of this transgenic insecticidal crop in a wild-relative plant population. We assessed the factors of competition, resource availability and diamondback moth (Plutella xylostella) infestation on plant population dynamics. As expected, Bt OSR performed better than wild mustard in mixed populations under herbivore attack in habitats with enough resources, whereas wild mustard had higher fitness when Bt OSR was rarer in habitats with limited resources. Results suggest that the presence of insect-resistant transgenic plants could decrease the growth of wild mustard and Bt OSR plants and their populations, especially under high herbivore pressure.

Seed bank dynamics govern persistence of Brassica hybrids in crop and natural habitats

BACKGROUND AND AIMS

Gene flow from crops to their wild relatives has the potential to alter population growth rates and demography of hybrid populations, especially when a new crop has been genetically modified (GM). This study introduces a comprehensive approach to assess this potential for altered population fitness, and uses a combination of demographic data in two habitat types and mathematical (matrix) models that include crop rotations and outcrossing between parental species.

METHODS

Full life-cycle demographic rates, including seed bank survival, of non-GM Brassica rapa × B. napus F1 hybrids and their parent species were estimated from experiments in both agricultural and semi-natural habitats. Altered fitness potential was modelled using periodic matrices including crop rotations and outcrossing between parent species.

KEY RESULTS

The demographic vital rates (i.e. for major stage transitions) of the hybrid population were intermediate between or lower than both parental species. The population growth rate (λ) of hybrids indicated decreases in both habitat types, and in a semi-natural habitat hybrids became extinct at two sites. Elasticity analyses indicated that seed bank survival was the greatest contributor to λ. In agricultural habitats, hybrid populations were projected to decline, but with persistence times up to 20 years. The seed bank survival rate was the main driver determining persistence. It was found that λ of the hybrids was largely determined by parental seed bank survival and subsequent replenishment of the hybrid population through outcrossing of B. rapa with B. napus.

CONCLUSIONS

Hybrid persistence was found to be highly dependent on the seed bank, suggesting that targeting hybrid seed survival could be an important management option in controlling hybrid persistence. For local risk mitigation, an increased focus on the wild parent is suggested. Management actions, such as control of B. rapa, could indirectly reduce hybrid populations by blocking hybrid replenishment.

Hybridisation and introgression between Brassica napus and B. rapa in the Netherlands

We used flow cytometry, chromosome counting and AFLP markers to investigate gene flow from the crop plant oilseed rape, Brassica napus (AACC) to wild B. rapa (AA) in the Netherlands. From 89 B. napus source populations investigated, all near cropping fields or at transhipment sites, only 19 contained a B. rapa population within a 2.5-km radius. During our survey we found only three populations with F1 hybrids (AAC), as recognized by their nine extra chromosomes and by flow cytometry. These hybrids were all collected in mixed populations where the two species grew in close proximity. Populations with F1 hybrids were not close to crops, but instead were located on road verges with highly disturbed soils, in which both species were probably recruited from the soil seed bank. Many plants in the F2, BC1 or higher backcrosses are expected to carry one to eight C chromosomes. However, these plants were not observed among the hybrids. We further investigated introgression with molecular markers (AFLP) and compared sympatric B. rapa populations (near populations of B. napus) with control populations of B. rapa (no B. napus within at least 7 km). We found no difference between sympatric and control populations in the number of C markers in B. rapa, nor did we find that these sympatric populations closely resembled B. napus. Our data show that hybrids occur but also suggest no recent introgression of alleles from the crop plant B. napus into wild B. rapa in the Dutch populations studied.

Unexpected diversity of feral genetically modified oilseed rape (Brassica napus L.) despite a cultivation and import ban in Switzerland

Despite cultivation and seed import bans of genetically modified (GM) oilseed rape (Brassica napus L.), feral GM plants were found growing along railway lines and in port areas at four sites in Switzerland in 2011 and 2012. All GM plants were identified as glyphosate-resistant GM event GT73 (Roundup Ready, Monsanto). The most affected sites were the Rhine port of Basel and the St. Johann freight railway station in Basel. To assess the distribution and intra- and interspecific outcrossing of GM oilseed rape in more detail, we monitored these two sites in 2013. Leaves and seed pods of feral oilseed rape plants, their possible hybridization partners and putative hybrid plants were sampled in monthly intervals and analysed for the presence of transgenes by real-time PCR. Using flow cytometry, we measured DNA contents of cell nuclei to confirm putative hybrids. In total, 2787 plants were sampled. The presence of GT73 oilseed rape could be confirmed at all previously documented sampling locations and was additionally detected at one new sampling location within the Rhine port. Furthermore, we found the glufosinate-resistant GM events MS8xRF3, MS8 and RF3 (all traded as InVigor, Bayer) at five sampling locations in the Rhine port. To our knowledge, this is the first time that feral MS8xRF3, MS8 or RF3 plants were detected in Europe. Real-time PCR analyses of seeds showed outcrossing of GT73 into two non-GM oilseed rape plants, but no outcrossing of transgenes into related wild species was observed. We found no hybrids between oilseed rape and related species. GM plants most frequently occurred at unloading sites for ships, indicating that ship cargo traffic is the main entry pathway for GM oilseed rape. In the future, it will be of major interest to determine the source of GM oilseed rape seeds.

Environmental risk assessment of GE plants under low-exposure conditions

The requirement for environmental risk assessment (ERA) of genetically engineered (GE) plants prior to large scale or commercial introduction into the environment is well established in national laws and regulations, as well as in international agreements. Since the first introductions of GE plants in commercial agriculture in the 1990s, a nearly universal paradigm has emerged for conducting these assessments based on a few guiding principles. These include the concept of case-by-case assessment, the use of comparative assessments, and a focus of the ERA on characteristics of the plant, the introduced trait, and the receiving environment as well as the intended use. In practice, however, ERAs for GE plants have frequently focused on achieving highly detailed characterizations of potential hazards at the expense of consideration of the relevant levels of exposure. This emphasis on exhaustive hazard characterization can lead to great difficulties when applied to ERA for GE plants under low-exposure conditions. This paper presents some relevant considerations for conducting an ERA for a GE plant in a low-exposure scenario in the context of the generalized ERA paradigm, building on discussions and case studies presented during a session at ISBGMO 12.

Possibilities of direct introgression from Brassica napus to B. juncea and indirect introgression from B. napus to related Brassicaceae through B. juncea

The impact of genetically modified canola (Brassica napus) on biodiversity has been examined since its initial stage of commercialization. Various research groups have extensively investigated crossability and introgression among species of Brassicaceae. B. rapa and B. juncea are ranked first and second as the recipients of cross-pollination and introgression from B. napus, respectively. Crossability between B. napus and B. rapa has been examined, specifically in terms of introgression from B. napus to B. rapa, which is mainly considered a weed in America and European countries. On the other hand, knowledge on introgression from B. napus to B. juncea is insufficient, although B. juncea is recognized as the main Brassicaceae weed species in Asia. It is therefore essential to gather information regarding the direct introgression of B. napus into B. juncea and indirect introgression of B. napus into other species of Brassicaceae through B. juncea to evaluate the influence of genetically modified canola on biodiversity. We review information on crossability and introgression between B. juncea and other related Brassicaseae in this report.

How can flexibility be integrated into coexistence regulations? A review

Member states in the European Union (EU) implemented both ex ante coexistence regulations and ex post liability schemes to ensure that genetically modified (GM) and non-GM crops can be cultivated side by side without excluding any agricultural option. Although proportionate coexistence is best achieved if regulated in a flexible manner, most implemented coexistence regulations merely rely on rigid measures. Flexible coexistence regulations, however, would reduce the regulatory burden on certain agricultural options and avoid jeopardizing economic incentives for coexistence. Flexibility can be integrated at: (i) the regulatory level by relaxing the rigidity of coexistence measures in ex ante regulations, yet without offsetting incentives to implement coexistence measures; (ii) the farm level by recommending the use of pollen barriers instead of large and fixed isolation distances; and (iii) the national/regional level by allowing diversified coexistence measures, which are adapted to the heterogeneity of farming in the EU. Owing to difficulties of implementation, the adoption of flexible and proportionate coexistence regulations will inevitably entail challenges.

Consequences of gene flow between oilseed rape (Brassica napus) and its relatives

Numerous studies have focused on the probability of occurrence of gene flow between transgenic crops and their wild relatives and the likelihood of transgene escape, which should be assessed before the commercial release of transgenic crops. This review paper focuses on this issue for oilseed rape, Brassica napus L., a species that produces huge numbers of pollen grains and seeds. We analyze separately the distinct steps of gene flow: (1) pollen and seeds as vectors of gene flow; (2) spontaneous hybridization; (3) hybrid behavior, fitness cost due to hybridization and mechanisms of introgression; (4) and fitness benefit due to transgenes (e.g. herbicide resistance and Bt toxin). Some physical, biological and molecular means of transgene containment are also described. Although hybrids and first generation progeny are difficult to identify in fields and non-crop habitats, the literature shows that transgenes could readily introgress into Brassica rapa, Brassica juncea and Brassica oleracea, while introgression is expected to be rare with Brassica nigra, Hirschfeldia incana and Raphanus raphanistrum. The hybrids grow well but produce less seed than their wild parent. The difference declines with increasing generations. However, there is large uncertainty about the evolution of chromosome numbers and recombination, and many parameters of life history traits of hybrids and progeny are not determined with satisfactory confidence to build generic models capable to really cover the wide diversity of situations. We show that more studies are needed to strengthen and organize biological knowledge, which is a necessary prerequisite for model simulations to assess the practical and evolutionary outputs of introgression, and to provide guidelines for gene flow management.

EFSA's scientific activities and achievements on the risk assessment of genetically modified organisms (GMOs) during its first decade of existence: looking back and ahead

Genetically modified organisms (GMOs) and derived food and feed products are subject to a risk analysis and regulatory approval before they can enter the market in the European Union (EU). In this risk analysis process, the role of the European Food Safety Authority (EFSA), which was created in 2002 in response to multiple food crises, is to independently assess and provide scientific advice to risk managers on any possible risks that the use of GMOs may pose to human and animal health and the environment. EFSA's scientific advice is elaborated by its GMO Panel with the scientific support of several working groups and EFSA's GMO Unit. This review presents EFSA's scientific activities and highlights its achievements on the risk assessment of GMOs for the first 10 years of its existence. Since 2002, EFSA has issued 69 scientific opinions on genetically modified (GM) plant market registration applications, of which 62 for import and processing for food and feed uses, six for cultivation and one for the use of pollen (as or in food), and 19 scientific opinions on applications for marketing products made with GM microorganisms. Several guidelines for the risk assessment of GM plants, GM microorganisms and GM animals, as well as on specific issues such as post-market environmental monitoring (PMEM) were elaborated. EFSA also provided scientific advice upon request of the European Commission on safeguard clause and emergency measures invoked by EU Member States, annual PMEM reports, the potential risks of new biotechnology-based plant breeding techniques, evaluations of previously assessed GMOs in the light of new scientific publications, and the use of antibiotic resistance marker genes in GM plants. Future challenges relevant to the risk assessment of GMOs are discussed. EFSA's risk assessments of GMO applications ensure that data are analysed and presented in a way that facilitates scientifically sound decisions that protect human and animal health and the environment.