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Breeding has been used successfully for many years in the fruit industry, giving rise to most of today's commercial fruit cultivars. More recently, new molecular breeding techniques have addressed some of the constraints of conventional breeding. However, the development and commercial introduction of such novel fruits has been slow and limited with only five genetically engineered fruits currently produced as commercial varieties—virus-resistant papaya and squash were commercialized 25 years ago, whereas insect-resistant eggplant, non-browning apple, and pink-fleshed pineapple have been approved for commercialization within the last 6 years and production continues to increase every year. Advances in molecular genetics, particularly the new wave of genome editing technologies, provide opportunities to develop new fruit cultivars more rapidly. Our review, emphasizes the socioeconomic impact of current commercial fruit cultivars developed by genetic engineering and the potential impact of genome editing on the development of improved cultivars at an accelerated rate. [ABSTRACT FROM AUTHOR]

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus responsible for an ongoing human pandemic (COVID-19). There is a massive international effort underway to develop diagnostic reagents, vaccines, and antiviral drugs in a bid to slow down the spread of the disease and save lives. One part of that international effort involves the research community working with plants, bringing researchers from all over the world together with commercial enterprises to achieve the rapid supply of protein antigens and antibodies for diagnostic kits, and scalable production systems for the emergency manufacturing of vaccines and antiviral drugs. Here, we look at some of the ways in which plants can and are being used in the fight against COVID-19. The current COVID-19 pandemic has created an immediate massive demand for diagnostic reagents based on SARS-CoV-2 RNA/proteins and corresponding antibodies, placing immense strain on the supply and distribution chain. Transient expression in plants could address the shortage by achieving rapid, larger-scale production, complemented by longer-term higher-volume production in transgenic plants. The same technology used to produce diagnostic reagents could also be used to produce vaccine candidates (SARS-CoV-2 subunits and virus-like particles) as well as therapeutic antibodies and antiviral proteins. It will be necessary to pool the international resources of molecular farming research groups and industry to capitalize on expertise, although distributed production using local infrastructure is the key to reaching all parts of the world. [ABSTRACT FROM AUTHOR]

In this article, we explore the intellectual property ( IP) landscape relevant to the production and commercialization of Carolight™, a transgenic multivitamin corn variety created on humanitarian grounds to address micronutrient deficiencies in low-and-middle-income countries. The successful production of this variety requires IP rights risk management because there is a strong protection on inventions and processes via patent portfolios in both developing and industrialized countries. The IP framework is complex, and specialist patent lawyers are usually employed to perform such analysis, but the costs cannot always be met by small, publicly funded projects. We report an alternative strategy, a do-it-yourself patent analysis, to produce a review with limited legal value that can nevertheless lay the foundations for a subsequent more in-depth professional freedom-to-operate opinion. [ABSTRACT FROM AUTHOR]

Carotenoids are health-promoting organic molecules that act as antioxidants and essential nutrients. We show that chickens raised on a diet enriched with an engineered corn variety containing very high levels of four key carotenoids (β-carotene, lycopene, zeaxanthin and lutein) are healthy and accumulate more bioavailable carotenoids in peripheral tissues, muscle, skin and fat, and more retinol in the liver, than birds fed on standard corn diets (including commercial corn supplemented with colour additives). Birds were challenged with the protozoan parasite Eimeria tenella and those on the high-carotenoid diet grew normally, suffered only mild disease symptoms (diarrhoea, footpad dermatitis and digital ulcers) and had lower faecal oocyst counts than birds on the control diet. Our results demonstrate that carotenoid-rich corn maintains poultry health and increases the nutritional value of poultry products without the use of feed additives. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess whether endosperm-specific carotenoid biosynthesis influenced core metabolic processes in maize embryo and endosperm and how global seed metabolism adapted to this expanded biosynthetic capacity. Although enhancement of carotenoid biosynthesis was targeted to the endosperm of maize kernels, a concurrent up-regulation of sterol and fatty acid biosynthesis in the embryo was measured. Targeted terpenoid analysis, and non-targeted metabolomic, proteomic, and transcriptomic profiling revealed changes especially in carbohydrate metabolism in the transgenic line. In-depth analysis of the data, including changes of metabolite pools and increased enzyme and transcript concentrations, gave a first insight into the metabolic variation precipitated by the higher upstream metabolite demand by the extended biosynthesis capacities for terpenoids and fatty acids. An integrative model is put forward to explain the metabolic regulation for the increased provision of terpenoid and fatty acid precursors, particularly glyceraldehyde 3-phosphate and pyruvate or acetyl-CoA from imported fructose and glucose. The model was supported by higher activities of fructokinase, glucose 6-phosphate isomerase, and fructose 1,6-bisphosphate aldolase indicating a higher flux through the glycolytic pathway. Although pyruvate and acetyl-CoA utilization was higher in the engineered line, pyruvate kinase activity was lower. A sufficient provision of both metabolites may be supported by a by-pass in a reaction sequence involving phosphoenolpyruvate carboxylase, malate dehydrogenase, and malic enzyme. [ABSTRACT FROM AUTHOR]

Multivitamin corn is a novel genetically engineered variety that simultaneously produces high levels of β-carotene, ascorbate and folate, and therefore has the potential to address simultaneously multiple micronutrient deficiencies caused by the lack of vitamins A, B9 and C in developing country populations. As part of the development process for genetically engineered crops and following European Food Safety Authority (EFSA) recommendations, multivitamin corn must be tested in whole food/feed sub-chronic animal feeding studies to ensure there are no adverse effects, and potential allergens must be identified. We carried out a 28-day toxicity assessment in mice, which showed no short-term sub-acute evidence of diet-related adverse health effects and no difference in clinical markers (food consumption, body weight, organ/tissue weight, haematological and biochemical blood parameters and histopathology) compared to mice fed on a control diet. A subsequent 90-day sub-chronic feeding study again showed no indications of toxicity compared to mice fed on control diets. Our data confirm that diets enriched with multivitamin corn have no adverse effects on mice, do not induce any clinical signs of toxicity and do not contain known allergens. [ABSTRACT FROM AUTHOR]

Transgenic plants that are being developed for commercial cultivation must be tested under field conditions to monitor their effects on surrounding wildlife and conventional crops. Developers also use this opportunity to evaluate the performance of transgenic crops in a typical environment, although this is a matter of commercial necessity rather than regulatory compliance. Most countries have adapted existing regulations or developed new ones to deal specifically with transgenic crops and their commodities. The European Union (EU) is renowned, or perhaps notorious, for having the broadest and most stringent regulations governing such field trials in the world. This reflects its nominal adherence to the precautionary approach, which assumes all transgenic crops carry an inherent risk. Therefore, field trials in the EU need to demonstrate that the risk associated with deploying a transgenic crop has been reduced to the level where it is regarded as acceptable within the narrowly defined limits of the regulations developed and enforced (albeit inconsistently) by national and regional governments, that is, that there is no greater risk than growing an equivalent conventional crop. The involvement of national and regional competent authorities in the decision-making process can add multiple layers of bureaucracy to an already-intricate process. In this review, we use country-based case studies to show how the EU, national and regional regulations are implemented, and we propose strategies that could increase the efficiency of regulation without burdening developers with further unnecessary bureaucracy. [ABSTRACT FROM AUTHOR]

Bacillus thuringiensis (Bt) is a soil bacterium that forms spores during the stationary phase of its growth cycle. The spores contain crystals, predominantly comprising one or more Cry and/or Cyt proteins (also known as δ-endotoxins) that have potent and specific insecticidal activity. Different strains of Bt produce different types of toxin, each of which affects a narrow taxonomic group of insects. Therefore, Bt toxins have been used as topical pesticides to protect crops, and more recently the proteins have been expressed in transgenic plants to confer inherent pest resistance. Bt transgenic crops have been overwhelmingly successful and beneficial, leading to higher yields and reducing the use of chemical pesticides and fossil fuels. However, their deployment has attracted some criticism particularly with regard to the potential evolution of pest-resistant insect strains. Here, we review recent progress in the development of Bt technology and the countermeasures that have been introduced to prevent the evolution of resistant insect populations. [ABSTRACT FROM AUTHOR]

Lutein and zeaxanthin cannot be synthesized de novo in humans, and although lutein is abundant in fruit and vegetables, good dietary sources of zeaxanthin are scarce. Certain corn varieties provide adequate amounts because the ratio of endosperm β : ε lycopene cyclase activity favours the β-carotene/zeaxanthin branch of the carotenoid pathway. We previously described a transgenic corn line expressing the early enzymes in the pathway (including lycopene β-cyclase) and therefore accumulating extraordinary levels of β-carotene. Here, we demonstrate that introgressing the transgenic mini-pathway into wild-type yellow endosperm varieties gives rise to hybrids in which the β : ε ratio is altered additively. Where the β : ε ratio in the genetic background is high, introgression of the mini-pathway allows zeaxanthin production at an unprecedented 56 μg/g dry weight. This result shows that metabolic synergy between endogenous and heterologous pathways can be used to enhance the levels of nutritionally important metabolites. [ABSTRACT FROM AUTHOR]

Combinatorial nuclear transformation is a novel method for the rapid production of multiplex-transgenic plants, which we have used to dissect and modify a complex metabolic pathway. To demonstrate the principle, we transferred 5 carotenogenic genes controlled by different endosperm-specific promoters into a white maize variety deficient for endosperm carotenoid synthesis. We recovered a diverse population of transgenic plants expressing different enzyme combinations and showing distinct metabolic phenotypes that allowed us to identify and complement rate-limiting steps in the pathway and to demonstrate competition between β-carotene hydroxylase and bacteriaβ-carotene ketolase for substrates in 4 sequential steps of the extended pathway. Importantly, this process allowed us to generate plants with extraordinary levels of β-carotene and other carotenoids, including complex mixtures of hydroxycarotenoids and ketocarote- noids. Combinatorial transformation is a versatile approach that could be used to modify any metabolic pathway and pathways controlling other biochemical, physiological, or developmental processes. [ABSTRACT FROM AUTHOR]

The article presents a letter to the editor concerning the global production of genetically modified crops.

We generated and characterized a transgenic wheat ( Triticum aestivum L.) population expressing constitutively an oat arginine decarboxylase ( ADC) cDNA. Transgenic wheat plants expressing the transgene had a significant increase in ADC activity with no concomitant changes in ODC activity. We measured 2-fold increases in putrescine, spermidine and spermine content in leaves of transgenic plants compared to wild-type. These plants also exhibited significant increases in the three polyamines in seeds (7-fold putrescine, 2.5-fold spermidine and 1.8-fold spermine). This significant polyamine accumulation was heritable in subsequent generations. In order to characterize molecularly this population we cloned a partial TaADC cDNA. This sequence was used as a probe to ascertain the presence of two distinct ADC transcripts in wheat. Further DNA analyses confirmed the presence of at least two distinct ADC genes in the wheat genome. Our results demonstrate that polyamine levels can be altered in transgenic wheat plants resulting in phenotypically normal and fertile plants. This transgenic wheat population will serve as useful germplasm to embark on further in depth studies to ascertain the role of polyamines in abiotic stress responses. [ABSTRACT FROM AUTHOR]

The adoption of insect-resistant transgenic crops has been increasing annually at double-digit rates since the commercial release of first-generation maize and cotton expressing a single modified Bacillus thuringiensis toxin (Bt) nine years ago. Studies have shown that these Bt crops can be successfully deployed in agriculture, which has led to a decrease in pesticide usage, and that they are environmentally benign. However, the sustainability and durability of pest resistance continues to be discussed. In this review, we focus on the science that underpins second- and third-generation insect-resistant transgenic plants and examine the appropriateness and relevance of models that are currently being used to determine deployment strategies to maximize sustainability and durability. We also review strategies that are being developed for novel approaches to transgenic insect pest control. [Copyright &y& Elsevier]

A letter to the editor is presented which discussed a proposal by the European Commission on July 13, 2010 that will give member states the freedom to veto the cultivation of genetically modified (GM) crops on their own territory without providing any scientific evidence relating to new risks.

Abstract: Ketocarotenoids such as astaxanthin and canthaxanthin have important applications in the nutraceutical, cosmetic, food and feed industries. Astaxanthin is derived from β-carotene by 3-hydroxylation and 4-ketolation at both ionone end groups. These reactions are catalyzed by β-carotene hydroxylase and β-carotene ketolase, respectively. The hydroxylation reaction is widespread in higher plants, but ketolation is restricted to a few bacteria, fungi, and some unicellular green algae. The recent cloning and characterization of β-carotene ketolase genes in conjunction with the development of effective co-transformation strategies permitting facile co-integration of multiple transgenes in target plants provided essential resources and tools to produce ketocarotenoids in planta by genetic engineering. In this review, we discuss ketocarotenoid biosynthesis in general, and characteristics and functional properties of β-carotene ketolases in particular. We also describe examples of ketocarotenoid engineering in plants and we conclude by discussing strategies to efficiently convert β-carotene to astaxanthin in transgenic plants. [Copyright &y& Elsevier]

Abstract: Maize (Zea mays), the world''s third most important cereal crop, was the first plant developed into a commercial platform for molecular pharming in the field. Although there are now many different plant-based platforms, including leafy crops, fruit and vegetable crops, other cereals, aquatic plants, algae and systems based on plant viruses and cultured plant cells, maize still demonstrates the unique combination of advantages that made it the first choice for many researchers. In this review, we look at the drivers for using maize as a platform for large-scale production of recombinant pharmaceutical proteins. As well as discussing the technical merits and limitations of the species, we explore the regulatory burden that plant-made pharmaceuticals carry, and use scientific data to expose the misconceptions surrounding the perceived ‘risks’ of using maize as a pharmaceutical crop. [Copyright &y& Elsevier]

Highlights: [•] We highlight paradoxes in current EU agricultural policies, specifically on GE products, which are contradictory and irrational. [•] There is a huge discrepancy in EU regulations on home-grown and imported GE products. [•] We provide case studies to show how EU agricultural policies are damaging the European and International economy. [•] We show how research and innovation is being stifled and driven abroad. [•] We recommend a bottom-up revision of the regulatory framework governing GE crops. [Copyright &y& Elsevier]

Abstract: Maize (also known as corn) is a domesticated cereal grain that has been grown as food and animal feed for tens of thousands of years. It is currently the most widely grown crop in the world, and is used not only for food/feed but also to produce ethanol, industrial starches and oils. Maize is now at the beginning of a new agricultural revolution, where the grains are used as factories to synthesize high-value molecules. In this article we look at the diversity of high-value products from maize, recent technological advances in the field and the emerging regulatory framework that governs how transgenic maize plants and their products are grown, used and traded. [ABSTRACT FROM AUTHOR]

Abstract: Carotenoids fulfill many processes that are essential for normal growth and development in plants, but they are also responsible for the breathtaking variety of red-to-yellow colors we see in flowers and fruits. Although such visual diversity helps to attract pollinators and encourages herbivores to distribute seeds, humans also benefit from the aesthetic properties of flowers and an entire floriculture industry has developed on the basis that new and attractive varieties can be produced. Over the last decade, much has been learned about the impact of carotenoid metabolism on flower color development and the molecular basis of flower color. A number of different regulatory mechanisms have been described ranging from the transcriptional regulation of genes involved in carotenoid synthesis to the control of carotenoid storage in sink organs. This means we can now explain many of the natural colorful varieties we see around us and also engineer plants to produce flowers with novel and exciting varieties that are not provided by nature. [ABSTRACT FROM AUTHOR]

The genomics revolution has taught us that a great deal of information can be derived from studying many genes or proteins at the same time. We are beginning to see this approach blossoming in applied research. Instead of attempting to generate useful transgenic plants by introducing single genes, we now see an increasing number of researchers embracing multigene transfer (MGT) as an approach to generate plants with more ambitious phenotypes. MGT allows researchers to achieve goals that were once impossible – the import of entire metabolic pathways, the expression of entire protein complexes, the development of transgenic crops simultaneously engineered to produce a spectrum of added-value compounds. The potential appears limitless. [Copyright &y& Elsevier]