Search Results (32)

The coexistence of genetically modified (GM) and non-GM crops has been a subject of considerable concern, particularly in the context of the extensive utilisation of GM crops. In response to this concern, various countries have devised coexistence strategies that are tailored to their respective national contexts, taking into account economic, political, technological and public acceptability factors. In the context of planting, countries such as the United States and Brazil have adopted a strategy of coexistence management, whereby the responsibility for implementing isolation measures falls upon premium producers. In contrast, the European Union, Japan and other countries that import GM crops have enacted legislation requiring growers to adhere to stringent isolation measures to prevent the mixing of GM and non-GM crops. Internationally, GM products are distinguished by a labelling management system to satisfy the public’s right to know and choose and to realise the coexistence of GM and non-GM during circulation and consumption. When considered in the context of China’s specific national conditions, particularly the prevalence of a small-scale peasant economy, it is recommended that China draw upon the lessons learned from the field coexistence strategies employed in countries that have adopted GM planting. This recommendation involves the refinement and enhancement of existing labelling management practices as well as the formulation of a coexistence management policy that is characterised by cost savings, efficiency gains and robust operational capabilities. The implementation of these measures is expected to foster the commercialisation of GM soybean and maize in China. Full article

Approximately 25% of cereal grains present with contamination caused by fungi and the presence of mycotoxins that may cause severe adverse effects when consumed. Maize has been genetically engineered to present different traits, such as fungal or insect resistance and herbicide tolerance. This systematic review compared the observable quantities, via meta-analysis, of four mycotoxins (aflatoxins—AFL, fumonisins—FUM, deoxynivalenol—DON, zearalenone—ZEA) between genetically modified (GM) and conventional maize kernels. This study was conducted following the PRISMA guidelines, with searches performed using PubMed, Web of Science, Scopus, Google Scholar, and CAPES journals databases. Analyses were conducted using RevMan v.5.4 software. Transgenic maize showed a 58% reduction in total mycotoxins (p < 0.001) compared to conventional maize. FUM were the most impacted, with a 59% reduction (p < 0.001) in GM maize. AFL and ZEA levels were also lower in GM maize by 49% (p = 0.02) and 51% (p < 0.001), respectively. On the other hand, DON levels increased by 6% (p < 0.001) in GM maize compared to conventional maize. However, results for ZEA and DON were inconclusive due to the limited research and sample sizes. We conclude that transgenic maize reduces total mycotoxins by over 50%, primarily fumonisin and aflatoxin. Most studies presented maize varieties that were resistant to insects or herbicides, not fungal pathogens, showing a positive collateral effect of these genetic alterations. Therefore, transgenic maize appears to be a safer product for animal and human consumption from a toxicological point of view. Further studies with larger sample sizes are needed to confirm our findings for ZEA and DON in transgenic maize. Full article

The genetically modified (GM) maize DBN9936 with a biosafety certificate will soon undergo commercial application. To monitor the safety of DBN9936 maize, three genomic DNA (gDNA) reference materials (RMs) (DBN9936a, DBN9936b, and DBN9936c) were prepared with nominal copy number ratios of 100%, 3%, and 1% for the DBN9936 event, respectively. DBN9936a was prepared from the leaf tissue gDNA of DBN9936 homozygotes, while DBN9936b and DBN9936c were prepared by the quantitative mixing of gDNA from the leaf tissues of DBN9936 homozygotes and non-GM counterparts. Validated DBN9936/zSSIIb duplex droplet digital PCR was demonstrated to be an accurate reference method for conducting homogeneity study, stability study, and collaborative characterization. The minimum intake for one measurement was determined to be 2 μL, and the gDNA RMs were stable during transport at 37 °C for 14 days and storage at −20 °C for 18 months. Each gDNA RM was certified for three property values: DBN9936 event copy number concentration, zSSIIb reference gene copy number concentration, and DBN9936/zSSIIb copy number ratio. The measurement uncertainty of the certified values took the uncertainty components related to possible inhomogeneity, instability, and characterization into account. This batch of gDNA RMs can be used for calibration and quality control when quantifying DBN9936 events. Full article

The fall armyworm, Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae), is an agricultural pest native to tropical and subtropical regions of the Americas, with considerable potential for global invasion and seasonal migration. Although genetically modified (GM) plants have shown positive impacts on the economy and the environment as they synthesize proteins that act as natural insecticides and are primarily intended to protect the crops from damage by specific pests, potential effects of Bt toxins on non-target organisms can occur. This experiment aimed to evaluate the potential impacts on the parasitoid Palmistichus elaeisis (Hymenoptera: Eulophidae), using the pupae of Spodoptera frugiperda (Lepidoptera: Noctuidae) as hosts, which were fed with transgenic maize genotypes such as Herculex^®, expressing Cry1F protein, and PowerCore^®, expressing Cry1F, Cry1A.105, and Cry2Ab2 proteins, or their non-transgenic isohybrid. The experiment was conducted in a completely randomized design with ten replicates. Spodoptera frugiperda larvae were fed ad libitum with transgenic and non-transgenic maize until the pupal stage and then individually exposed to six P. elaeisis females for 78 h. The total number of adults, emerged males, tibia size, cephalic capsule size, and parasitoid body size were not influenced by host feeding. However, the number of emerged females from the Herculex^® and PowerCore^® treatments was lower than that for the isohybrid treatment. The sex ratio and longevity of parasitoids emerging from PowerCore^® were 1.05 and 1.26 times lower, respectively, than that of those from the isohybrid. Furthermore, the number of dead P. elaeisis within the host pupa was 10.56 times higher in the PowerCore^® genotype. Combining Bt proteins within pyramided genotypes should cause minimal impacts and promote the conservation and integration of beneficial insects. The results of this study provide helpful information for developing effective and compatible integrated pest management (IPM) strategies. Full article

Small mammals are bioindicator organisms, and, through their gut microbiota (GM), could be carriers of pathogens and resistant bacteria. Also, wild GM composition has been suggested to have large implications for conservation efforts. Seventeen bacterial species were obtained from intestinal samples of Bulgarian yellow-necked mice (Apodemus flavicollis) and bank voles (Myodes glareolus) via classic microbiological cultivation and biochemical identification. Twelve Gram-negative—Escherichia coli, Yersinia enterocolitica, Yersinia kristensenii, Hafnia alvei, Serratia liquefaciens, Serratia marcescens, Serratia proteamaculans, Pseudescherichia vulneris, Klebsiella pneumoniae ssp. ozaenae, Enterobacter cloacea, Pantoea agglomerans, Pseudomonas fluorescens group—and five Gram-positive bacteria, Enterococcus faecium, Enterococcus faecalis, Enterococcus hirae, Bacillus thuringiensis, and Lysinibacillus sphaericus, were discovered. Enterobacteriaceae was the most abundant family. The isolates belonged to one of the major reported taxa in rodents, Firmicutes (the Gram-positive species) and to the less abundant, but still among the first, phyla, Proteobacteria (the Gram-negative strains). We did not find any members of the other major phylum, Bacteroidetes, likely due to lack of metagenomic techniques. E. coli and Y. enterocolitica were confirmed with polymerase chain reaction. Almost all strains had pathogenic potential, but the good condition of the test animals suggests their commensal role. The Y. enterocolitica strains did not have the ail pathogenicity gene. There was high prevalence of multi-drug resistance (MDR), but for the expected species with high level of intrinsic resistance, such as the enterococci and S. marcescens. E. coli and some other species had very low antimicrobial resistance (AMR), in line with other studies of wild rodents. Many of the strains had biotechnological potential; e.g., B. thuringiensis is the most used biological insecticide, with its proteins incorporated into the Bt genetically modified maize. The GM of the tested wild mice and voles from Bulgaria proved to be a source of bacterial diversity; many of the strains were promising in terms of biotechnology, and, in addition, the samples did not contain the African swine fever virus. Full article

Genetic engineering technology offers opportunities to improve many important agronomic traits in crops, including insect-resistance. However, genetically modified (GM) exogenous proteins in edible tissues of transgenic crops has become an issue of intense public concern. To advance the application of GM techniques in maize, a Cre/loxP-based strategy was developed for manipulating the transgenes in green tissues while locking them in non-green tissues. In the strategy, the site-specific excision can be used to switch on or off the expression of transgenes at specific tissues. In this work, two basic transgenic maize, named KEY, carrying the Cre gene, and LOCK, containing the Vip3A gene with a blocked element, were obtained based on their separate fusion gene cassettes. The expression level and concentration of Vip3A were observed with a high specific accumulation in the green tissues (leaf and stem), and only a small amount was observed in the root and kernel tissues in the KEY × LOCK hybrids. The insect resistance of transgenic maize against two common lepidopteran pests, Ostrinia furnacalis and Spodoptera frugiperda, was assessed in the laboratory and field. The results indicate that the hybrids possessed high resistance levels against the two pests, with mortality rates above 73.6% and damage scales below 2.4 compared with the control group. Our results suggest that the Cre/loxP-mediated genetic engineering approach has a competitive advantage in GM maize. Overall, the findings from this study are significant for providing a feasible strategy for transgenes avoiding expression in edible parts and exploring novel techniques toward the biosafety of GM plants. Full article

Genetically modified (GM) maize is one of the earliest GM crops to have achieved large-scale commercial cultivation globally, and it is of great significance to excel in the development and implementation of safety policy regarding GM, and in its technical oversight. This article describes the general situation regarding genetically modified maize, including its varieties, applications, relevant laws and regulations, and so on. From a technical point of view, we summarize and critically analyze the existing methods for detecting nucleic acid levels in genetically modified maize. The nucleic acid extraction technology used for maize is explained, and the introduction of traditional detection techniques, which cover variable-temperature and isothermal amplification detection technology and gene chip technology, applications in maize are described. Moreover, new technologies are proposed, with special attention paid to nucleic acid detection methods using sensors. Finally, we review the current limitations and challenges of GM maize nucleic acid testing and share our vision for the future direction of this field. Full article

The classification of GM and non-GM maize kernels is fundamental for further analysis of the gene action in maize. Therefore, a complete and novel detection scheme based on near-infrared spectra was designed to distinguish GM and non-GM maize kernels. Hyperspectral images (935–1720 nm) of 777 maize kernels from 3 kinds were captured, and the average spectra of the maize kernels were extracted for modeling analysis. The classical modeling methods based on feature engineering were first studied, and the backpropagation neural network–genetic algorithm model showed the best performance with a prediction accuracy of 0.861. Then, novel modeling methods based on deep learning were developed. To dig out the interactive information between different bands and match the application scenarios, the original spectra were transformed into two-dimensional matrices before establishing the deep learning models. A modified convolution neural network (i.e., VGG net) with dilated convolution was finally constructed to classify the maize kernels, and the prediction accuracy reached 0.961. This research provides a referential and novel way to detect GM maize kernels. Future research will improve the detection scheme for monitoring unauthorized GM organisms by introducing the visualization technology of deep learning. Full article

Genetically modified (GM) crops tolerant to glyphosate have delivered significant economic benefits in farm management. However, the evolution of glyphosate resistance in weeds due to prolonged intensive use of glyphosate poses a serious threat to this weed management system. It is highly desirable in China to deploy dual herbicide-tolerant corn at the very beginning of GM corn release to delay the development of weed resistance to herbicides. Here, we report the creation and characterization of a herbicide-tolerant corn event SCB-29 that expresses both cp4 epsps and bar genes. This transgenic maize is tolerant to glyphosate up to 3600 g a.e. ha⁻¹ and glufosinate up to 3600 g a.i. ha⁻¹, which are quadruple the recommended rates for the two herbicides, respectively. SCB-29 is an event with only a single copy of T-DNA inserted into chromosome 10 of the maize genome. An event-specific PCR detection method was established and three generations of SCB-29 were detected by event-specific PCR suggesting that the transgenes are stably integrated into the maize genome. Analysis of the expression levels of the transgenes among plants of multiple generations by enzyme-linked immunosorbent assays suggested that the expressions are stable over different generations. Moreover, the major agronomic performances of SCB-29 appear to be similar to those of non-transgenic maize, suggesting that SCB-29 is not likely to have yield drag. Therefore, SCB-29 is an excellent herbicide-tolerant candidate to be developed into a commercial herbicide tolerance transgenic event. Full article

Genetically modified (GM) technology is of great significance for increasing crop production, protecting biodiversity, and reducing environmental pollution. However, with the frequent occurrence of safety events regarding GM foods, more and more disputes have arisen over the potential safety of transgenic technology. It is particularly necessary to find a fast and accurate method for transgenic product identification. In this research, mid-infrared spectroscopy, coupled with chemometric methods, was applied to discriminate GM maize from its non-GM parent. A total of 120 GM maize and 120 non-GM maize samples were prepared, and the spectral information in the range of 400–4000 cm⁻¹ was collected. After acquiring the spectra, wavelet transform (WT) was used to preprocess the data, and k-means was carried out to split all samples into calibration and prediction sets in the ratio of 2:1. Principal component analysis (PCA) was then conducted to qualitatively distinguish the two types of samples, and an apparent cluster was observed. Since the full spectrum covered a large amount of data and redundant information, we adopted the successive projections algorithm (SPA) to select optimal wavelengths for further analysis. Chemometrics, including partial least squares-discriminant analysis (PLS-DA), the k-nearest neighbor algorithm (KNN), and the extreme learning machine (ELM), were performed to establish classification models based on full spectra and optimal wavelengths. The overall results indicated that ELM models based on full spectra and optimal spectra showed better accuracy and reliability, with a 100% recognition rate in the calibration set and a 98.75% recognition rate in the prediction set. It has been confirmed that mid-infrared spectroscopy, combined with chemometric methods, can be a novel approach to identify transgenic maize. Full article

Genetically modified (GM) crops expressing insecticidal and herbicide-tolerant traits provide a new approach to agriculture production, but concerns about food safety were often raised by the public. The present research shows the findings of the nutritional assessment of ZDAB3 expressing insecticidal Cry proteins (Cry1Ab and Cry2Ab) and EPSPS protein (G10evo-EPSPS). The key nutrients and anti-nutrients of ZDAB3 maize were examined and contrasted with those of its non-transgenic control maize grown at the same locations during three planting seasons. The values for proximates, amino acids, fatty acids, minerals, vitamins, phytic acid, and trypsin inhibitor assessed for ZDAB3 were comparable to those of its non-transgenic control maize or within the range of values reported for other commercial lines. In addition, no adverse effects related to the G10evo-EPSPS protein in mammals were observed. These data indicated that the expression of Cry1Ab, Cry2Ab, and G10evo-EPSPS proteins in ZDAB3 maize does not affect the nutritional compositions, and ZDAB3 maize is equivalent to non-transgenic maize regarding those important compositions. Full article

Label-free quantitative proteomic (LFQ) and widely targeted metabolomic analyses were applied in the safety evaluation of three genetically modified (GM) maize varieties, BBL, BFL-1, and BFL-2, in addition to their corresponding non-GM parent maize. A total of 76, 40, and 25 differentially expressed proteins (DEPs) were screened out in BBL, BFL-1, and BFL-2, respectively, and their abundance compared was with that in their non-GM parents. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that most of the DEPs participate in biosynthesis of secondary metabolites, biosynthesis of amino acids, and metabolic pathways. Metabolomic analyses revealed 145, 178, and 88 differentially accumulated metabolites (DAMs) in the BBL/ZH58, BFL-1/ZH58, and BFL-2/ZH58×CH72 comparisons, respectively. KEGG pathway enrichment analysis showed that most of the DAMs are involved in biosynthesis of amino acids, and in arginine and proline metabolism. Three co-DEPs and 11 co-DAMs were identified in the seeds of these GM maize lines. The proteomic profiling of seeds showed that the GM maize varieties were not dramatically different from their non-GM control. Similarly, the metabolomic profiling of seeds showed no dramatic changes in the GM/non-GM maize varieties compared with the GM/GM and non-GM/non-GM maize varieties. The genetic background of the transgenic maize was found to have some influence on its proteomic and metabolomic profiles. Full article

ZDAX5 is a variety of herbicide-tolerant maize that contains the modified P450-N-Z1 gene isolated from Cynodon dactylon (L.) Pers. and the cp4 epsps gene isolated from the Agrobacterium tumefaciens strain CP4 and exhibits high tolerances to flazasulfuron and glyphosate under field conditions. Once ZDAX5 corn is available on the market, the evolution of herbicide-resistant weeds will be delayed by applying glyphosate and flazasulfuron to corn fields. Prior to commercialization, it is critical to assess the safety of ZDAX5 maize. Compositional analysis and feed consumption studies in rodents are an important consideration in the safety assessment of genetically modified crops. The nutritional components of ZDAX5 were analyzed and compared with those of its non-transgenic counterpart. The data showed that all the analyzed components in the herbicide-tolerant maize plants were substantially equivalent to those of its non-transgenic counterpart. Furthermore, most of the measured values from ZDAX5 were within the range of values reported for other commercial maize varieties. The sub-chronic feeding trial was carried out with grains from GM, and non-GM maize were independently added into rodent diets at concentrations of 12.5%, 25% and 50%. As a control, another set of rats was fed with a marketed diet. At the end of the 90-day feeding study, no negative effects associated with the consumption of GM maize were found. These results indicate that the herbicide-tolerant maize ZDAX5 is as nutritious and safe as non-transgenic maize. Full article

Certified reference materials (CRMs) is one of the critical requirements in a quantitative analytical method, such as in the quantification of genetically modified (GM) contents in food/feed products. Plasmid-DNA-based CRMs are becoming essential in GM content quantification. Herein, we report the construction of one plasmid DNA calibrant, pMON810, for the quantification of the GM maize event MON810 which is commercially planted and used for food/feeds worldwide, and the collaborative ring trial was used to validate its applicability. pMON10 was proven to have high specificity for the MON810 event. The limit of detection (LOD) and limit of quantification (LOQ) of real-time PCR assays of MON810 event and maize endogenous gene using pMON810 as calibrant was 2 copies/μL and 5 copies/μL, respectively. A total of eight laboratories participated in the ring trial and returned valid test results. Each sample was performed with three repeats and three parallels in each repeat. Statistical analysis of the ring trial results showed that pMON810 as a calibrant had high PCR efficiency (ranging from 0.885 to 1.008) and good linearity (ranging from 0.9933 to 0.9997) in MON810 and endogenous gene real-time PCR assays. The bias between the test values and true values ranged from 4.60 to 20.00% in the quantification of five blind samples. These results indicate that pMON810 is suitable for use as a calibrant for the quantification of MON810 events in routine lab analysis or to evaluate detection methods for MON810, as well as being used as a substitute for the matrix-based CRM of MON810. Full article

Dehydration-responsive element-binding (DREB) transcription factors regulate diverse processes during plant development. Here, a 2-year field study was conducted to assess the potential effects of DREB-genetically modified maize (GM1) on arthropod species and ecological communities. Arthropod abundance, diversity, and community composition in GM1 and its non-transformed counterpart maize variety, Chang 7-2, were compared using whole plant inspection, pitfall trap, and suction sampler methods. Based on Shannon–Wiener diversity, Simpson’s diversity, Pielou’s indexes, number of species, and total number of individuals, GM1 had a negligible effect on arthropod abundance and diversity. Redundancy analysis indicated that the composition of arthropod community was not associated with maize type in the three investigation methods, while it exhibited significant correlation with year and sampling time in whole plant inspection and suction sample methods, and distinctly correlated with sampling time in the pitfall trap method. Nonmetric multidimensional scaling analysis of variable factors in the three investigation methods showed that sampling time, rather than maize type or year, was closely related to the composition of arthropod community in the field. Our results provide direct evidence to support that DREB-GM maize had negligible effects on arthropods in the Jilin Province under natural conditions. Full article