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      Contamination of corn grain for human consumption with transgenic sequences in Paraguay

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          Abstract

          Abstract Corn is one of the most important economic, social and cultural agricultural products in Paraguay, being the main ingredient of several typical foods. Due to the cross-pollination of this plant, it can be contaminated with transgenic maize pollen found in nearby fields. The general objective of this research was to evaluate the presence of transgenic sequences in corn grains marketed in the Departments of Itapúa, Alto Paraná and Canindeyú for the preparation of flour for human consumption. We studied 18 samples of corn kernels marketed for the preparation of flour from the Departments of Itapúa, Alto Paraná and Canindeyú. The DNA was extracted using the Trimethyl Ammonium Bromide (CTAB) protocol. For the detection of the transgenic sequences, the polymerase chain reaction (PCR) method was used. The bands were analyzed visually and using the ImageJ program. The results showed the presence of 5 positive samples for the P-35S-CaMv promoter and 5 samples for the T-nos terminator, none of them presented both sequences sought in the same construction; this indicates that 10 of 18 samples were contaminated with transgenic sequences. These findings show that transgenic products are available in Paraguayan local markets without consumers being aware of this situation.

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          Most cited references 21

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          Transgenic DNA introgressed into traditional maize landraces in Oaxaca, Mexico.

          Concerns have been raised about the potential effects of transgenic introductions on the genetic diversity of crop landraces and wild relatives in areas of crop origin and diversification, as this diversity is considered essential for global food security. Direct effects on non-target species, and the possibility of unintentionally transferring traits of ecological relevance onto landraces and wild relatives have also been sources of concern. The degree of genetic connectivity between industrial crops and their progenitors in landraces and wild relatives is a principal determinant of the evolutionary history of crops and agroecosystems throughout the world. Recent introductions of transgenic DNA constructs into agricultural fields provide unique markers to measure such connectivity. For these reasons, the detection of transgenic DNA in crop landraces is of critical importance. Here we report the presence of introgressed transgenic DNA constructs in native maize landraces grown in remote mountains in Oaxaca, Mexico, part of the Mesoamerican centre of origin and diversification of this crop.
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            NAC transcription factors in plant multiple abiotic stress responses: progress and prospects

            Abiotic stresses adversely affect plant growth and agricultural productivity. According to the current climate prediction models, crop plants will face a greater number of environmental stresses, which are likely to occur simultaneously in the future. So it is very urgent to breed broad-spectrum tolerant crops in order to meet an increasing demand for food productivity due to global population increase. As one of the largest families of transcription factors (TFs) in plants, NAC TFs play vital roles in regulating plant growth and development processes including abiotic stress responses. Lots of studies indicated that many stress-responsive NAC TFs had been used to improve stress tolerance in crop plants by genetic engineering. In this review, the recent progress in NAC TFs was summarized, and the potential utilization of NAC TFs in breeding abiotic stress tolerant transgenic crops was also be discussed. In view of the complexity of field conditions and the specificity in multiple stress responses, we suggest that the NAC TFs commonly induced by multiple stresses should be promising candidates to produce plants with enhanced multiple stress tolerance. Furthermore, the field evaluation of transgenic crops harboring NAC genes, as well as the suitable promoters for minimizing the negative effects caused by over-expressing some NAC genes, should be considered.
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              Transgenes in Mexican maize: molecular evidence and methodological considerations for GMO detection in landrace populations

              A possible consequence of planting genetically modified organisms (GMOs) in centres of crop origin is unintended gene flow into traditional landraces. In 2001, a study reported the presence of the transgenic 35S promoter in maize landraces sampled in 2000 from the Sierra Juarez of Oaxaca, Mexico. Analysis of a large sample taken from the same region in 2003 and 2004 could not confirm the existence of transgenes, thereby casting doubt on the earlier results. These two studies were based on different sampling and analytical procedures and are thus hard to compare. Here, we present new molecular data for this region that confirm the presence of transgenes in three of 23 localities sampled in 2001. Transgene sequences were not detected in samples taken in 2002 from nine localities, while directed samples taken in 2004 from two of the positive 2001 localities were again found to contain transgenic sequences. These findings suggest the persistence or re-introduction of transgenes up until 2004 in this area. We address variability in recombinant sequence detection by analyzing the consistency of current molecular assays. We also present theoretical results on the limitations of estimating the probability of transgene detection in samples taken from landraces. The inclusion of a limited number of female gametes and, more importantly, aggregated transgene distributions may significantly lower detection probabilities. Our analytical and sampling considerations help explain discrepancies among different detection efforts, including the one presented here, and provide considerations for the establishment of monitoring protocols to detect the presence of transgenes among structured populations of landraces.
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                Author and article information

                Journal
                cta
                Food Science and Technology
                Food Sci. Technol
                Sociedade Brasileira de Ciência e Tecnologia de Alimentos (Campinas, SP, Brazil )
                0101-2061
                1678-457X
                2020
                Affiliations
                Encarnación Itapúa orgnameUniversidad Nacional de Itapúa orgdiv1Facultad de Ciencias y Tecnología Paraguay
                San Lorenzo Asunción orgnameUniversidad Nacional de Asunción orgdiv1Facultad Politécnica Paraguay
                Asunción orgnameCámara Paraguaya de Exportadores y Comercializadores de Cereales y Oleaginosas Paraguay
                San Lorenzo Asunción orgnameUniversidad Nacional de Asunción orgdiv1Dirección General de Investigación Científica y Tecnológica orgdiv2Centro Multidisciplinario de Investigaciones Tecnológicas Paraguay
                San Lorenzo Asunción orgnameUniversidad Nacional de Asunción orgdiv1Facultad de Ciencias Químicas Paraguay
                Article
                12209 S0101-20612020005012209 S0101-2061(20)00000012209
                10.1590/fst.35718

                This work is licensed under a Creative Commons Attribution 4.0 International License.

                Page count
                Figures: 0, Tables: 0, Equations: 0, References: 30, Pages: 0
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                food safety, GMO, cross-pollination, biotechnology

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