Transgenic Crops Research Articles

Deletion of the 3′ End of the Introduced cry1Ac Gene Retains the Insecticidal Activity in Transgenic Cotton

The structure and expression of exogenous genes in transgenic crops are critical for the target traits. R7569 has the same exogenous insertion structure as the transgenic insect-resistant cotton MON531 but with a deletion in the 3′ end of the cry1Ac gene and the terminator region. Thus, in the present study, transcription, expression, and insecticidal activity assays were conducted to determine the function of the truncated cry1Ac gene. R7569 has a truncated cry1Ac gene with a length of 2554 bp encoding 881 amino acids, and the transcription termination site was mainly concentrated downstream of the truncated position and extended 160–270 bp from the truncated position using rapid amplification of cDNA ends (RACE). The transcript levels of the cry1Ac gene in R7569 were significantly higher than those of MON531 implants, except for during the boll stage. The content of the Cry1Ac protein in R7569 was higher than that of MON531 in the cotton leaf in all three periods. The corrected mortality rates of R7569 and MON531 against bollworms were 93.09% and 88.83%, respectively. The LC50 value of R7569 was 0.732 ng/g (dw), indicating a high level of resistance to bollworm. In this study, for the first time, we found a partial deletion of the target gene in commercially applied transgenic crops, and the partial deletion of the 3′ end of the cry1Ac gene retained a better transcription, expression level, and insecticidal activity, which can provide a specific case for the safety evaluation of transgenic crops.

Transforming Fruit Crop Development: Advances in Transgenic Methods

India is second in the world after China in production fruits around the world and these crops play one important role in human diet because they provide Vitamins, minerals, diet fiber and phytochemicals. Flower cultivation in India is considered one of the products for which the demand is constantly increasing, and the export potential of these crops is very high in the global market, but there are problems in the gardening process due to pathogens, pests and weeds, and it requires a large amount of plant protection products per hectare. Genetically modified/GM), Crops enable breeders to bring favorable genes, often already inaccessible, already in elite farming, improving their value significantly and providing unique opportunities to control insects and other pathogens. This novel "molecular farming" provides a very large Possibility, but stringent rules will be required and Control mechanisms to avoid new, potentially serious risks to human health, although possible contamination of food supply. The seed-ambed technology has the potential to reduce pesticide use by increasing plants' resistance to insects. Food security improves by reducing pesticides remain. In addition, Herbicide-Toller Transgenic Crop can help reduce the plow in the fields, so that Save fuel trust for the use of less tractor, whatever it is It reduces the soil structure by reducing its Eater. Transgenic horticulture crops could make important contributions to sustainable horticulture production.

Plant characterization of insect-protected soybean

Insect-protected soybean (SIP) that produces the Cry1A.105 and Cry2Ab2 insecticidal crystal proteins has been developed to provide protection from feeding damage caused by targeted lepidopteran insect pests. Typically, as part of environmental risk assessment (ERA), plant characterization is conducted, and the data submitted to regulatory agencies prior to commercialization of genetically modified (GM) crops. The objectives of this research were to: (a) compare soybean with and without the SIP trait in plant characterization field trials designed to fulfill requirements for submissions to global regulatory agencies and address China-specific considerations and (b) compare risk assessment conclusions across regions and the methodologies used in the field trials. The soybean with and without the SIP trait in temperate, tropical, and subtropical germplasm were planted in replicated multi-location trials in the USA (in 2012 and 2018) and Brazil (in 2013/2014 and 2017/2018). Agronomic, phenotypic, plant competitiveness, and survival characteristics were assessed for soybean entries with and without the SIP trait. Regardless of genetic background, growing region, season, or testing methodology, the risk assessment conclusions were the same: the evaluated insect-protected soybean did not differ from conventional soybean in evaluated agronomic, phenotypic, competitiveness, and survival characteristics indicating no change in plant pest/weed potential. These results reinforce the concept of data transportability across global regions, different seasons, germplasm, and methodologies that should be considered when assessing environmental risks of GM crops.

Genome-wide identification and phylogenetic analysis of the tetraspanin gene family in lepidopteran insects and expression profiling analysis in Helicoverpa armigera.

The tetraspanin gene family encodes cell-surface proteins that span the membrane 4 times and play critical roles in a wide range of biological processes across numerous organisms. Recent findings highlight the involvement of a tetraspanin of the lepidopteran pest Helicoverpa armigera in resistance to Bacillus thuringiensis Cry insecticidal proteins, which are extensively used in transgenic crops. Thus, a better understanding of lepidopteran tetraspanins is urgently needed. In the current study, genome scanning in 10 lepidopteran species identified a total of 283 sequences encoding potential tetraspanins. Based on conserved cysteine patterns in the large extracellular loop and their phylogenetic relationships, these tetraspanins were classified into 8 subfamilies (TspA to TspH). Six ancestral introns were identified within lepidopteran tetraspanin genes. Tetraspanins in TspA, TspB, TspC, and TspD subfamilies exhibit highly similar gene organization, while tetraspanins in the remaining 4 subfamilies exhibited variation in intron loss and/or gain during evolution. Analysis of chromosomal distribution revealed a lepidopteran-specific cluster of 10 to 11 tetraspanins, likely formed by tandem duplication events. Selective pressure analysis indicated negative selection across all orthologous groups, with ω values ranging between 0.004 and 0.362. However, positive selection was identified at 18 sites within TspB5, TspC5, TspE3, and TspF10. Furthermore, spatiotemporal expression analysis of H. armigera tetraspanins demonstrated variable expression levels across different developmental stages and tissues, suggesting diverse functions of tetraspanin members in this globally important insect pest. Our findings establish a solid foundation for subsequent functional investigations of tetraspanins in lepidopteran species.

Unfolding consumer purchase intentions toward genetically modified rice with nutritional benefits in Bangladesh

Notwithstanding ongoing efforts through supplementation and fortification programs, the burden of vitamin A deficiency remains high among poor and rural populations. To address this, a pro-vitamin A-enriched genetically modified (GM) rice variety, known as Golden Rice (GR), has been developed as a complementary, cost-effective micronutrient strategy. Despite its potential, the success of its future implementation will heavily rely on the acceptance and purchase intention of target populations. Therefore, this study investigated the determinants of GR purchase intention from a survey of 540 consumers from rural Bangladesh. On average, consumers exhibited a strong intention to purchase GR. Hierarchical regression analysis demonstrated that sociodemographic factors (age), cognitive and behavioral factors (prior knowledge, perceived benefits about GR, attitudes toward GM crops, and dietary choices), and expectations of GR marketing (overall, price, distribution) positively influenced consumers’ purchase intention of GR. On the other hand, having more negative risk perceptions and higher income levels reduced consumers’ intentions. By using a between-subjects design based on five information treatments, the role of information is examined in two ways, i.e., information length and presentation format. Findings of a series of two-way ANOVAs revealed that exposure to more detailed information about GR significantly influenced consumers’ purchase intentions, especially when the level of expectations was low. Additionally, information presented through video or an information wheel proved more effective than text. These findings provide valuable insights for policymakers and health planners in devising communication strategies and decision-making regarding this valuable but controversial micronutrient strategy.

The evolution of media reportage on GMOs in Ghana following approval of first GM crop

ABSTRACT Ghana’s parliament in 2011 passed the Biosafety Act to allow for the application of genetically modified organism (GMO) technology in the country’s agriculture. In a vibrant democracy, there have been extensive media discussions on whether GM crops will benefit or harm citizens. In June 2022, the state GMO regulator, the National Biosafety Authority (NBA), approved the country’s first GM crop (Bt cowpea) for environmental release, declaring the crop does not present an altered environmental risk or a food/feed safety concern. This study identified 3 of the country’s most vibrant digital news outlets and did a content analysis of all GMO stories reported 18 months pre- and post-approval to assess whether the approval changed the focus of GMO issues the media reports on. 91 articles were identified. The results show media reports on the likely impact of GMOs on the country’s food security shot up after the approval. However, media reports on the possible health, sociocultural, and environmental impact of GMOs declined. We observe the media and the public appear interested in deliberations on how the technology could address or worsen food insecurity and urge agricultural biotechnology actors in Ghana to focus on that in their sensitization activities.

CRISPR/Cas9-induced knockout of an amino acid permease gene (AAP6) reduced Arabidopsis thaliana susceptibility to Meloidogyne incognita

BackgroundPlant-parasitic root-knot nematode (Meloidogyne incognita) causes global yield loss in agri- and horticultural crops. Nematode management options rely on chemical method. However, only a handful of nematicides are commercially available. Resistance breeding efforts are not sustainable because R gene sources are limited and nematodes have developed resistance-breaking populations against the commercially available Mi-1.2 gene-expressing tomatoes. RNAi crops that manage nematode infection are yet to be commercialized because of the regulatory hurdles associated with transgenic crops. The deployment of the CRISPR/Cas9 system to improve nematode tolerance (by knocking out the susceptibility factors) in plants has emerged as a feasible alternative lately.ResultsIn the present study, a M. incognita-responsive susceptibility (S) gene, amino acid permease (AAP6), was characterized from the model plant Arabidodpsis thaliana by generating the AtAAP6 overexpression line, followed by performing the GUS reporter assay by fusing the promoter of AtAAP6 with the β-glucuronidase (GUS) gene. Upon challenge inoculation with M. incognita, overexpression lines supported greater nematode multiplication, and AtAAP6 expression was inducible to the early stage of nematode infection. Next, using CRISPR/Cas9, AtAAP6 was selectively knocked out without incurring any growth penalty in the host plant. The ‘Cas9-free’ homozygous T3 line was challenge inoculated with M. incognita, and CRISPR-edited A. thaliana plants exhibited considerably reduced susceptibility to nematode infection compared to the non-edited plants. Additionally, host defense response genes were unaltered between edited and non-edited plants, implicating the direct role of AtAAP6 towards nematode susceptibility.ConclusionThe present findings enrich the existing literature on CRISPR/Cas9 research in plant-nematode interactions, which is quite limited currently while compared with the other plant-pathogen interaction systems.

Eco-friendly and Targeted through Next-generation Approaches to Insect Pest Management

Insect pests pose significant challenges to agricultural productivity, human health, and ecosystem stability worldwide. Traditional pest management approaches, heavily reliant on broad-spectrum chemical insecticides, have led to the development of insecticide resistance, unintended effects on non-target organisms, and environmental contamination. In response to these challenges, next-generation approaches to insect pest management are emerging, focusing on eco-friendly and targeted strategies. This review article explores the latest advancements in sustainable pest management, including the use of biopesticides, semiochemicals, biotechnology-based approaches, and integrated pest management (IPM) strategies. Biopesticides, derived from natural sources such as plants, microorganisms, and insects, offer effective and environmentally benign alternatives to synthetic insecticides. Semiochemicals, including pheromones and allelochemicals, can be exploited for pest monitoring, mating disruption, and attract-and-kill strategies. Biotechnology-based approaches, such as RNA interference (RNAi), CRISPR/Cas9 gene editing, and transgenic crops, provide novel tools for targeting specific pest species and reducing reliance on chemical insecticides. IPM strategies, which combine multiple pest management tactics based on ecological principles, offer a holistic and sustainable approach to pest control. The adoption of these next-generation approaches faces challenges, including regulatory hurdles, public acceptance, and the need for further research and development. However, by embracing eco-friendly and targeted pest management strategies, we can reduce the environmental impact of insect pest control, promote biodiversity conservation, and ensure sustainable food production for a growing global population. Future research should focus on optimizing and integrating these approaches, understanding their long-term ecological impacts, and developing effective knowledge transfer mechanisms to promote their widespread adoption.

Binding Analysis of Sf-SR-C MAM Domain and Sf-FGFR Ectodomain to Vip3Aa.

Bacillus thuringiensis Vip3Aa has been widely used in transgenic crops to resist the erosion of insects. The Scavenger Receptor-C (SR-C) and Fibroblast Growth Factor Receptor (FGFR) of Spodoptera frugiperda (Sf-SR-C and Sf-FGFR) have formerly been identified as the cell receptors of Vip3Aa. However, the interaction mechanism of Vip3Aa binding to Sf-SR-C or Sf-FGFR is still unknown. Here, we purified the MAM domain of Sf-SR-C (Sf-MAM) and the Sf-FGFR ectodomain expressed extracellularly by Sf9 cells. We then solved the crystal structure of the Sf-MAM domain. Structure docking analysis of the Sf-MAM and Vip3Aa C-terminal domain (CTD) excluded the possibility of the two proteins binding. A further surface plasmon resonance (SPR) assay also revealed that the Sf-MAM and Sf-FGFR ectodomain could not bind to the Vip3Aa protein. Our results have raised the urgency of determining the authentic cell receptor for Vip3Aa.

Plant Synthetic Promoters

This article examines the structure and functions of the plant synthetic promoters frequently used to precisely regulate complex regulatory routes. It details the composition of native promoters and their interacting proteins to provide a better understanding of the tasks associated with synthetic promoter development. The production of synthetic promoters is performed by relatively small libraries produced generally by basic molecular or genetic engineering methods such as cis-element shuffling or domain swapping. The article also describes the preparation of large-scale libraries supported by synthetic DNA fragments, directed evolution, and machine or deep-learning methodologies. The broader application of novel, synthetic promoters reduces the prevalence of homology-based gene silencing or improves the stability of transgenes. A particularly interesting group of synthetic promoters are bidirectional forms, which can enable the expression of up to eight genes by one regulatory element. The introduction and controlled expression of several genes after one transgenic event strongly decreases the frequency of such problems as complex segregation patterns and the random integration of multiple transgenes. These complications are commonly observed during the transgenic crop development enabled by traditional, multistep transformation using genetic constructs containing a single gene. As previously tested DNA promoter fragments demonstrate low complexity and homology, their abundance can be increased by using orthogonal expression systems composed of synthetic promoters and trans-factors that do not occur in nature or arise from different species. Their structure, functions, and applications are rendered in the article. Among them are presented orthogonal systems based on transcription activator-like effectors (dTALEs), synthetic dTALE activated promoters (STAPs) and dCas9-dependent artificial trans-factors (ATFs). Synthetic plant promoters are valuable tools for providing precise spatiotemporal regulation and introducing logic gates into the complex genetic traits that are important for basic research studies and their application in crop plant development. Precisely regulated metabolic routes are less prone to undesirable feedback regulation and energy waste, thus improving the efficiency of transgenic crops.

Minimizing IP issues associated with gene constructs encoding the Bt toxin - a case study

BackgroundAs part of a publicly funded initiative to develop genetically engineered Brassicas (cabbage, cauliflower, and canola) expressing Bacillus thuringiensis Crystal (Cry)-encoded insecticidal (Bt) toxin for Indian and Australian farmers, we designed several constructs that drive high-level expression of modified Cry1B and Cry1C genes (referred to as Cry1BM and Cry1CM; with M indicating modified). The two main motivations for modifying the DNA sequences of these genes were to minimise any licensing cost associated with the commercial cultivation of transgenic crop plants expressing CryM genes, and to remove or alter sequences that might adversely affect their activity in plants.ResultsTo assess the insecticidal efficacy of the Cry1BM/Cry1CM genes, constructs were introduced into the model Brassica Arabidopsis thaliana in which Cry1BM/Cry1CM expression was directed from either single (S4/S7) or double (S4S4/S7S7) subterranean clover stunt virus (SCSV) promoters. The resulting transgenic plants displayed a high-level of Cry1BM/Cry1CM expression. Protein accumulation for Cry1CM ranged from 5.18 to 176.88 µg Cry1CM/g dry weight of leaves. Contrary to previous work on stunt promoters, we found no correlation between the use of either single or double stunt promoters and the expression levels of Cry1BM/Cry1CM genes, with a similar range of Cry1CM transcript abundance and protein content observed from both constructs. First instar Diamondback moth (Plutella xylostella) larvae fed on transgenic Arabidopsis leaves expressing the Cry1BM/Cry1CM genes showed 100% mortality, with a mean leaf damage score on a scale of zero to five of 0.125 for transgenic leaves and 4.2 for wild-type leaves.ConclusionsOur work indicates that the modified Cry1 genes are suitable for the development of insect resistant GM crops. Except for the PAT gene in the USA, our assessment of the intellectual property landscape of components presents within the constructs described here suggest that they can be used without the need for further licensing. This has the capacity to significantly reduce the cost of developing and using these Cry1M genes in GM crop plants in the future.

Effect of soil pH and mineralogy on the sorption and desorption of phosphite and phosphate in Ultisols of the Southeastern Coastal Plain

AbstractThe development of transgenic crop varieties capable of utilizing phosphite (Phi) as a phosphorus (P) source is a promising strategy to increase P use efficiency while decreasing reliance on phosphate (Pi)‐based fertilizers. However, little information is available on Phi sorption and desorption in soils. We conducted batch experiments to investigate the sorption of Phi and Pi by three Ultisols from the Coastal Plain of the southeastern United States. At the soils' acidic field pH (pH 4.7–6.2), Pi had a higher affinity than Phi for soil solids, where maximum sorbed concentrations of Pi were an average of 44% greater than those of Phi. The sorption of both P species decreased when experiments were repeated adjusting soil pH to 6.5. More Phi than Pi was recovered during desorption experiments, indicating that Phi was more reversibly sorbed and, therefore, may be more plant‐available than Pi. Multiple linear regression between calculated linear distribution coefficients (KD; 10 mg P L−1 input solutions) and soil properties suggested that amorphous Al‐ and Fe‐oxides controlled Pi sorption. Alternatively, amorphous Al‐oxides and gibbsite controlled Phi sorption. Our results show that a lower affinity of Phi than Pi in Ultisols could improve P availability for plant uptake of Phi‐based fertilizers but may increase the risk of soil P buildup over time.

Farmers’ Knowledge, Attitude and Experience in the Application and Management of Pesticides

A survey was conducted on some vegetable farmers from a few selected vegetable growing areas in Bangladesh to know their social aspects, pesticide knowledge, practices, safety measures, resources and effects of pesticides. A survey questionnaire was developed and sent to 90 randomly selected vegetable farmers to determine to what extent they used pesticides. Almost 87% of the farmers’ stored pesticides in their houses without safety consideration but only about 13% used special storage. About 78.7% of farmers never read the label before applying pesticides. The most protective clothes reported by the farmers were nose masks (18.2%), and about three-fourths (71.7%) of them did not use any protective clothing. The majority (61.8%) of the farmers threw away their empty containers, and only 16.9% burned them. The majority of farmers (92.1%) applied pesticides as both curative and preventive measures. Almost all farmers reported that infested pests were identified by themselves by observing damage to flowers & fruits (86.5%) and leaves & green parts (13.5%). Most of the farmers (64%) selected pesticides for controlling pests by themselves, and 28.1% with the help of experienced farmers. Nearly 45.0% of respondents have moderate knowledge, and 44.8% have good knowledge in pesticide application and management. The most common pesticide related illnesses and injuries reported by respondents were headache/dizziness (44.9%), weakness (33.7%), stomach cramps (29.2%), and blue-red vision (16.9%). Only 23.6% of farmers observed that pesticides decrease plant yield, and 18.0% of farmers knew that pesticides destroy soil microorganisms. As the environment and human health were poorly considered, only 19.1% of respondents were bio-pesticides, 4.5% were organic pesticides, 2.2% were non-persistence pesticides, and 2.2% were natural enemy users. Respondents have very poor knowledge about modern pest control methods like beneficial microorganisms (4.7%), beneficial insects (3.5%), biological control of pests (3.5%), IPM (2.3%), SIT (1.2%), and GMO crops (1.2%). Farmers’ age was correlated negatively with education (r = -0.380) and positively with experience (r = 0.909, P < 0.01). Pesticide related illness and injuries had a significant correlation with age (r = 0.465) and experience (r = 0.395). Jagannath University Journal of Life and Earth Sciences, 9(2): 111–124, 2023 (December)

Toxicity of Bt Protein on Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) Fed With Corn Leaves in Paraguay

The fall armyworm Spodoptera frugiperda is the most destructive pest in corn cultivation in Paraguay with yield losses of 20 to 70%. The adoption of genetically modified crops (GMO) is a valid technique for managing this pest. The objective of this investigation was to evaluate the toxicity among Bt events used locally; determining mortality and important biological parameters. The S. frugiperda population previously collected from the field was raised under laboratory conditions fed with leaves from events MIR162TM (Vip3A19), VT3ProTM (Cry1A105, Cry2Ab2, Cry3Bb), PowerCoreTM (Cry1A105, Cry1F, Cry2Ab2) and a treatment with non-maize. Bt BR106TM. The mortality of 120 larvae was evaluated for each treatment and the viability until the adult stage of those larvae that managed to survive the different treatments was observed. A high toxicity effect was verified with 100% mortality of neonatal larvae fed with the MIR162TM (Vip3A19) event; as for the other events, 86% and 61% VT3ProTM (Cry1A105, Cry2Ab2, Cry3Bb), and PowerCoreTM (Cry1A105, Cry1F, Cry2Ab2) respectively; with 13% mortality for the non-Bt control variety BR106TM. The oviposition period, viability and number of eggs laid in adults surviving the PowerCoreTM (Cry1A105, Cry1F, Cry2Ab2) and VT3ProTM (Cry1A105, Cry2Ab2, Cry3Bb) events were reduced, affecting the fecundity of the surviving insect population.

Toxicity of Bt Protein on Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) Fed With Corn Leaves in Paraguay

The fall armyworm Spodoptera frugiperda is the most destructive pest in corn cultivation in Paraguay with yield losses of 20 to 70%. The adoption of genetically modified crops (GMO) is a valid technique for managing this pest. The objective of this investigation was to evaluate the toxicity among Bt events used locally; determining mortality and important biological parameters. The S. frugiperda population previously collected from the field was raised under laboratory conditions fed with leaves from events MIR162TM (Vip3A19), VT3ProTM (Cry1A105, Cry2Ab2, Cry3Bb), PowerCoreTM (Cry1A105, Cry1F, Cry2Ab2) and a treatment with non-maize. Bt BR106TM. The mortality of 120 larvae was evaluated for each treatment and the viability until the adult stage of those larvae that managed to survive the different treatments was observed. A high toxicity effect was verified with 100% mortality of neonatal larvae fed with the MIR162TM (Vip3A19) event; as for the other events, 86% and 61% VT3ProTM (Cry1A105, Cry2Ab2, Cry3Bb), and PowerCoreTM (Cry1A105, Cry1F, Cry2Ab2) respectively; with 13% mortality for the non-Bt control variety BR106TM. The oviposition period, viability and number of eggs laid in adults surviving the PowerCoreTM (Cry1A105, Cry1F, Cry2Ab2) and VT3ProTM (Cry1A105, Cry2Ab2, Cry3Bb) events were reduced, affecting the fecundity of the surviving insect population.

Challenges for the Post-Market Environmental Monitoring in the European Union Imposed by Novel Applications of Genetically Modified and Genome-Edited Organisms.

Information on the state of the environment is important to achieve the objectives of the European Green Deal, including the EU's Biodiversity Strategy for 2030. The existing regulatory provisions for genetically modified organisms (GMOs) foresee an obligatory post-market environmental monitoring (PMEM) of potential adverse effects upon release into the environment. So far, GMO monitoring activities have focused on genetically modified crops. With the advent of new genomic techniques (NGT), novel GMO applications are being developed and may be released into a range of different, non-agricultural environments with potential implications for ecosystems and biodiversity. This challenges the current monitoring concepts and requires adaptation of existing monitoring programs to meet monitoring requirements. While the incorporation of existing biodiversity monitoring programs into GMO monitoring at the national level is important, additional monitoring activities will also be required. Using case examples, we highlight that monitoring requirements for novel GMO applications differ from those of GM crop plants previously authorized for commercial use in the European Union.

Modernizing and harmonizing regulatory data requirements for genetically modified crops-perspectives from a workshop.

Genetically modified (GM) crops that have been engineered to express transgenes have been in commercial use since 1995 and are annually grown on 200 million hectares globally. These crops have provided documented benefits to food security, rural economies, and the environment, with no substantiated case of food, feed, or environmental harm attributable to cultivation or consumption. Despite this extensive history of advantages and safety, the level of regulatory scrutiny has continually increased, placing undue burdens on regulators, developers, and society, while reinforcing consumer distrust of the technology. CropLife International held a workshop at the 16th International Society of Biosafety Research (ISBR) Symposium to examine the scientific basis for modernizing global regulatory frameworks for GM crops. Participants represented a spectrum of global stakeholders, including academic researchers, GM crop developers, regulatory consultants, and regulators. Concurrently examining the considerations of food and feed safety, along with environmental safety, for GM crops, the workshop presented recommendations for a core set of data that should always be considered, and supplementary (i.e., conditional) data that would be warranted only on a case-by-case basis to address specific plausible hypotheses of harm. Then, using a case-study involving a hypothetical GM maize event expressing two familiar traits (insect protection and herbicide tolerance), participants were asked to consider these recommendations and discuss if any additional data might be warranted to support a science-based risk assessment or for regulatory decision-making. The discussions during the workshop highlighted that the set of data to address the food, feed, and environmental safety of the hypothetical GM maize, in relation to a conventional comparator, could be modernized compared to current global regulatory requirements. If these scientific approaches to modernize data packages for GM crop regulation were adopted globally, GM crops could be commercialized in a more timely manner, thereby enabling development of more diverse GM traits to benefit growers, consumers, and the environment.

Bt-Modified Transgenic Rice May Shift the Composition and Diversity of Rhizosphere Microbiota.

Plants significantly shape root-associated microbiota, making rhizosphere microbes useful environmental indicator organisms for safety assessment. Here, we report the pyrosequencing of the bacterial 16S ribosomal RNA in rhizosphere soil samples collected from transgenic cry1Ab/cry1Ac Bt rice Huahui No. 1 (GM crop) and its parental counterpart, Minghui63. We identified a total of 2579 quantifiable bacterial operational taxonomic units (OTUs). Many treatment-enriched microbial OTUs were identified, including 14 NonGM-enriched OTUs and 10 GM-enriched OTUs. OTUs belonging to the phyla Proteobacteria, Actinobacteria, Acidobacteria, Firmicutes, Nitrospirae, Chlorobi and GN04 were identified as statistically different in abundance between GM and the other two treatments. Compared with the different impacts of different rice varieties on microbiota, the impact of rice planting on microbiota is more obvious. Furthermore, Huahui No. 1 transgenic Bt rice had a greater impact on the rhizosphere bacterial communities than Minghui63. Early developmental stages of the transgenic Bt rice had a significant impact on many Bacillaceae communities. Soil chemical properties were not significantly altered by the presence of transgenic Bt rice. The peak concentration level of Bt protein products was detected during the seedling stage of transgenic Bt rice, which may be an intriguing factor for bacterial diversity variations. Based on these findings, we conclude that transgenic Bt rice has a significant impact on root-associated bacteria. This information may be leveraged in future environmental safety assessments of transgenic Bt rice varieties.

Manganese(II)-Enhanced Graphene Oxide Fluorescence Switch-Based Hybridization Chain Reaction for the Enzyme-Free and Sensitive Determination of Bacillus thuringiensis (Bt) in Transgenic Crops

Bacillus thuringiensis, as a special DNA sequence, has been introduced into crops for insect control. At the same time, the safety risk of transgenic crops has received wide concern. Herein, a simple, enzyme-free and sensitive novel nanosensor for the determination of Bacillus thuringiensis by manganese(II)-enhanced graphene oxide (GO) fluorescence switch (Mn(II)-GO-FS)-based hybridization chain reaction (HCR) signal amplification was developed. The high affinity of Mn(II) to oxygen-containing groups in double-stranded DNA and on the surface of GO was able to overcome the steric effect of rigid double chains and drive the efficient adsorption of HCR hairpin probes with sticky ends on GO. The efficient quenching of 6-carboxyfluorescein (FAM) labeled on the HCR hairpin probes guaranteed a low background. The Bacillus thuringiensis acted as a trigger to initiate a cascade of hybridization events between the two metastable HCR hairpin probes (H1 and H2) to polymerize into a nicked long double-helix structure (dsDNA). The products desorbed from the surface of GO and produced strong fluorescence. The results included a wide linear range (0.1 pM-50 nM) and a low detection limit (0.05 pM). This nanosensor was successfully applied to determine Bacillus thuringiensis in maize seeds with spiked recoveries between 97.5% and 103%. The Mn(II)-GO-FS had a simple design and was conveniently used for the determination of other special genes by changing the corresponding HCR hairpin probe sequence. Moreover, this novel nanosensor did not require harsh experimental conditions, operating in a neutral environment.

GMOIT: a tool for effective screening of genetically modified crops

BackgroundAdvancement in agricultural biotechnology has resulted in increasing numbers of commercial varieties of genetically modified (GM) crops worldwide. Though several databases on GM crops are available, these databases generally focus on collecting and providing information on transgenic crops rather than on screening strategies. To overcome this, we constructed a novel tool named, Genetically Modified Organisms Identification Tool (GMOIT), designed to integrate basic and genetic information on genetic modification events and detection methods.ResultsAt present, data for each element from 118 independent genetic modification events in soybean, maize, canola, and rice were included in the database. Particularly, GMOIT allows users to customize assay ranges and thus obtain the corresponding optimized screening strategies using common elements or specific locations as the detection targets with high flexibility. Using the 118 genetic modification events currently included in GMOIT as the range and algorithm selection results, a “6 + 4” protocol (six exogenous elements and four endogenous reference genes as the detection targets) covering 108 events for the four crops was established. Plasmids pGMOIT-1 and pGMOIT-2 were constructed as positive controls or calibrators in qualitative and quantitative transgene detection.ConclusionsOur study provides a simple, practical tool for selecting, detecting, and screening strategies for a sustainable and efficient application of genetic modification.