The assessment of field trials in GMO research around the world and their possible integration in field trials for variety registration

Comparative safety assessment of genetically modified crops: focus on equivalence with reference varieties could contribute to more efficient and effective field trials

The initial compositional analysis of plants plays an important role within the internationally harmonized comparative safety assessment approach for genetically modified plants. Current EFSA guidance prescribes two types of comparison, namely difference tests with regard to a conventional comparator or control, and equivalence tests with regard to a collection of commercial reference varieties. The experience gained so far shows that most of the statistically significant differences between the test and control can be discounted based on the fact that they are still within equivalence limits of reference varieties with a presumed history of safe use. Inclusion of a test variety and reference varieties into field trial design, and of the statistical equivalence test would already suffice for the purpose of finding relevant parameters that warrant further assessment, hence both the inclusion of a conventional counterpart and the performance of difference testing can be omitted. This would also allow for the inclusion of safety testing regimes into plant variety testing VCU (value for cultivation and use) or other, independent variety trials.

Recent Developments and Strategies for the Application of Agrobacterium-Mediated Transformation of Apple Malus × domestica Borkh

Genetic transformation has become an important tool in plant genome research over the last three decades. This applies not only to model plants such as Arabidopsis thaliana but also increasingly to cultivated plants, where the establishment of transformation methods could still pose many problems. One of such plants is the apple (Malus spp.), the most important fruit of the temperate climate zone. Although the genetic transformation of apple using Agrobacterium tumefaciens has been possible since 1989, only a few research groups worldwide have successfully applied this technology, and efficiency remains poor. Nevertheless, there have been some developments, especially in recent years, which allowed for the expansion of the toolbox of breeders and breeding researchers. This review article attempts to summarize recent developments in the Agrobacterium-mediated transformation strategies of apple. In addition to the use of different tissues and media for transformation, agroinfiltration, as well as pre-transformation with a Baby boom transcription factor are notable successes that have improved transformation efficiency in apple. Further, we highlight targeted gene silencing applications. Besides the classical strategies of RNAi-based silencing by stable transformation with hairpin gene constructs, optimized protocols for virus-induced gene silencing (VIGS) and artificial micro RNAs (amiRNAs) have emerged as powerful technologies for silencing genes of interest. Success has also been achieved in establishing methods for targeted genome editing (GE). For example, it was recently possible for the first time to generate a homohistont GE line into which a biallelic mutation was specifically inserted in a target gene. In addition to these methods, which are primarily aimed at increasing transformation efficiency, improving the precision of genetic modification and reducing the time required, methods are also discussed in which genetically modified plants are used for breeding purposes. In particular, the current state of the rapid crop cycle breeding system and its applications will be presented.

Current progress and challenges in crop genetic transformation

Plant transformation remains the most sought-after technology for functional genomics and crop genetic improvement, especially for introducing specific new traits and to modify or recombine already existing traits. Along with many other agricultural technologies, the global production of genetically engineered crops has steadily grown since they were first introduced 25 years ago. Since the first transfer of DNA into plant cells using Agrobacterium tumefaciens, different transformation methods have enabled rapid advances in molecular breeding approaches to bring crop varieties with novel traits to the market that would be difficult or not possible to achieve with conventional breeding methods. Today, transformation to produce genetically engineered crops is the fastest and most widely adopted technology in agriculture. The rapidly increasing number of sequenced plant genomes and information from functional genomics data to understand gene function, together with novel gene cloning and tissue culture methods, is further accelerating crop improvement and trait development. These advances are welcome and needed to make crops more resilient to climate change and to secure their yield for feeding the increasing human population. Despite the success, transformation remains a bottleneck because many plant species and crop genotypes are recalcitrant to established tissue culture and regeneration conditions, or they show poor transformability. Improvements are possible using morphogenetic transcriptional regulators, but their broader applicability remains to be tested. Advances in genome editing techniques and direct, non-tissue culture-based transformation methods offer alternative approaches to enhance varietal development in other recalcitrant crops. Here, we review recent developments in plant transformation and regeneration, and discuss opportunities for new breeding technologies in agriculture.

Comparison of the seed nutritional composition between conventional varieties and transgenic soybean overexpressing Physaria FAD3-1

BACKGROUND

PfFAD3 transgenic soybean expressing omega-3 fatty acid desaturase 3 of Physaria produces increased level of α-linolenic acid in seed. Composition data of non-transgenic conventional varieties is important in the safety assessment of the genetically-modified (GM) crops in the context of the natural variation.

RESULTS

The natural variation was characterized in seed composition of 13 Korean soybean varieties grown in three locations in South Korea for 2 years. Univariate analysis of combined data showed significant differences by variety and cultivation environment for proximates, minerals, anti-nutrients, and fatty acids. Percent variability analysis demonstrated that genotype, environment and the interaction of environment with genotype contributed to soybean seed compositions. Principal component analysis and orthogonal projections to latent structure discriminant analysis indicated that significant variance in compositions was attributable to location and cultivation year. The composition of three PfFAD3 soybean lines for proximates, minerals, anti-nutrients, and fatty acids was compared to a non-transgenic commercial comparator (Kwangankong, KA), and three non-transgenic commercial varieties grown at two sites in South Korea. Only linoleic and linolenic acids significantly differed in PfFAD3-1 lines compared to KA, which were expected changes by the introduction of the PfFAD3-1 trait in KA.

CONCLUSION

Genotype, environment, and the interaction of environment with genotype contributed to compositional variability in soybean. PfFAD3-1 soybean is equivalent to the conventional varieties with respect to these components. © 2020 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Compositional equivalence assessment of insect-resistant genetically modified rice using multiple statistical analyses

The safety of transgenic Bt rice containing bacteria-derived mCry1Ac gene from Bacillus thuringiensis (Bt) was assessed by conducting field trials at two locations for two consecutive years in South Korea, using the near-isogenic line comparator rice cultivar ('Ilmi', non-Bt rice) and four commercial cultivars as references. Compositional analyses included measurement of proximates, minerals, amino acids, fatty acids, vitamins, and antinutrients. Significant differences between Bt rice and non-Bt rice were detected; however, all differences were within the reference range. The statistical analyses, including analysis of % variability, analysis of similarities (ANOISM), similarity percentage (SIMPER) analysis, and permutational multivariate analysis of variance (PERMANOVA) were performed to study factors contributing to compositional variability. The multivariate analyses revealed that environmental factors more influenced rice components' variability than by genetic factors. This approach was shown to be a powerful method to provide meaningful evaluations between Bt rice and its comparators. In this study, Bt rice was proved to be compositionally equivalent to conventional rice varieties through multiple statistical methods.

Potato as a Model for Field Trials with Modified Gene Functions in Research and Translational Experiments

Gene technology and editing are not only biotechnological techniques for creating new crop varieties but are also tools for researchers to discover gene functions. Field trial following laboratory experiments is an important step in order to evaluate new functions since many phenotypes, and combinations thereof, are difficult to detect in controlled environments and molecular analyses are nowadays possible to do in the field. Here we describe a standard protocol for creating new potato lines and producing seed tubers for field trials within 1 year.

The more favorable attitude of the citizens toward GMOs supports a new regulatory framework in the European Union

Since 1996 till 2018, the global area cultivated with GM crops has increased 113-fold, making biotech crops one of the fastest adopted crop technology in the past decades. In the European Union, only two countries still cultivate one available transgenic crop event on minor hectarage. Moreover, the number of notifications for confined field trials has dramatically dropped in the last decade. All these are happening while the EU legislation on GM crops has come under severe criticism. The percentage of EU citizens concerned about the presence of GMOs in the environment has decreased from 30% (in 2002) to 19% (in 2011), while the level of concern about the use of GM ingredients in food or drinks has decreased from 63% (in 2005) to 27% (in 2019). The steadily increasing acceptance of the EU citizens of GMOs in the environment and food, as it was recorded by Eurobarometers, should additionally ease the way and support a positive change of the legal framework that regulates the GM crops' testing and commercial cultivation in the EU.

Transgenic crops for the agricultural improvement in Pakistan: a perspective of environmental stresses and the current status of genetically modified crops

Transgenic technologies have emerged as a powerful tool for crop improvement in terms of yield, quality, and quantity in many countries of the world. However, concerns also exist about the possible risks involved in transgenic crop cultivation. In this review, literature is analyzed to gauge the real intensity of the issues caused by environmental stresses in Pakistan. In addition, the research work on genetically modified organisms (GMOs) development and their performance is analyzed to serve as a guide for the scientists to help them select useful genes for crop transformation in Pakistan. The funding of GMOs research in Pakistan shows that it does not follow the global trend. We also present socio-economic impact of GM crops and political dimensions in the seed sector and the policies of the government. We envisage that this review provides guidelines for public and private sectors as well as the policy makers in Pakistan and in other countries that face similar environmental threats posed by the changing climate.

The Romanian experience and perspective on the commercial cultivation of genetically modified crops in Europe

Romania was the third country in Europe and the tenth in the world, to commercially adopt genetically modified crops in 1999, only 3 years after they were first marketed globally. Half a million hectares of transgenic herbicide resistant soybean and insect resistant maize were grown in Romania during an uninterrupted 17-year period. After several years of continued declining area, the commercial cultivation of transgenic plants recently ended. The commercial cultivation of transgenic crops in Romania remains legally and technically possible, according to the EU and national regulations. However, the declining area cultivated with these crops in Romania seems to be the result of farmers' conscious decision, while waiting for more profitable genetically modified crops to become available that better fit their needs. This expectation would be a logical result of the EU GMO opt-out Directive 2015/412 and the advent of the new plant breeding techniques. The GMO opt-out mechanism is still expected to unblock the EU authorization process after the large majority of the EU member states have already prohibited the cultivation of genetically modified organisms in their territory. As the new plant breeding techniques offer significant technical and economic advantages, they could be rapidly adopted by commercial breeders and farmers outside Europe. The Court of Justice of the European Union ruled that plants obtained with the new gene editing techniques must go through the same authorization procedure as transgenic plants. This decision is expected to delay the approval and availability of these new plant varieties on the EU market and their commercial cultivation.