The integrated risk assessment of transgenic rice Oryza sativa: A comparative proteomics approach

Proteomic Analysis of Bt cry1Ac Transgenic Oilseed Rape (Brassica napus L.)

Oilseed rape (Brassica napus L.) is an important cash crop, but transgenic oilseed rape has not been grown on a commercial scale in China. It is necessary to analyze the characteristics of transgenic oilseed rape before commercial cultivation. In our study, differential expression of total protein from the leaves in two transgenic lines of oilseed rape expressing foreign Bt Cry1Ac insecticidal toxin and their non-transgenic parent plant was analyzed using a proteomic approach. Only shared changes in both of the two transgenic lines were calculated. Fourteen differential protein spots were analyzed and identified, namely, eleven upregulated expressed protein spots and three downregulated protein spots. These proteins are involved in photosynthesis, transporter function, metabolism, protein synthesis, and cell growth and differentiation. The changes of these protein spots in transgenic oilseed rape may be attributable to the insertion of the foreign transgenes. However, the transgenic manipulation might not necessarily cause significant change in proteomes of the oilseed rape.

Spatial Lipidomics of EPSPS and PAT Transgenic and Non-Transgenic Soybean Seeds Using Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging

Herbicide-resistant soybeans are among the most widely planted transgenic crops. The in situ evaluation of spatial lipidomics in transgenic and non-transgenic soybeans is important for directly assessing the unintended effects of exogenous gene introduction. In this study, matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI)-based non-targeted analytical strategies were used for the first time for in situ detection and imaging of endogenous lipid distributions in transgenic (EPSPS and PAT genes) herbicide-resistant soybean (Glycine max Merrill) (S4003.14) and non-transgenic soybean (JACK) seeds. Statistical analysis revealed significant differences in lipids between S4003.14 and JACK seeds. The variable importance of projection analysis further revealed that 18 identified lipids, including six phosphatidylcholines (PCs), four phosphatidylethanolamines (PEs), five triacylglycerols (TAGs), and three cytidine diphosphate-diacylglycerols (CDP-DAGs), had the strongest differential expression between S4003.14 and JACK seeds. Among those, the upregulated expressions of PC(P-36:1), PC(36:2), PC(P-36:0), PC(37:5), PE(40:2), TAG(52:1), TAG(55:5), and CDP-DAG(37:2) and the downregulated expressions of PC (36:1), TAG(43:0), and three PEs (i.e., PE(P-38:1), PE(P-38:0), and PE(P-40:3)) were successfully found in the S4003.14 seeds, compared to these lipids detected in the JACK seeds. Meanwhile, the lipids of PC (44:8), CDP-DAG(38:0), and CDP-DAG(42:0) were uniquely detected in the S4003.14 soybean seeds, and TAG(45:2) and TAG(57:10) were detected as the unique lipids in the JACK seeds. The heterogeneous distribution of these lipids in the soybean seeds was also clearly visualized using MALDI-MSI. MSI results showed that lipid expression was significantly up/downregulated in S4003.14 seeds, compared to that in JACK seeds. This study improves our understanding of the unintended effects of herbicide-resistant EPSPS and PAT gene transfers on spatial lipidomes in soybean seeds and enables the continued progression of MALDI-MSI as an emerging, reliable, and rapid molecular imaging tool for evaluating unintended effects in transgenic plants.

Proteomic Advances in Cereal and Vegetable Crops

The importance of vegetables in human nutrition, such as cereals, which in many cases represent the main source of daily energy for humans, added to the impact that the incessant increase in demographic pressure has on the demand for these plant foods, entails the search for new technologies that can alleviate this pressure on markets while reducing the carbon footprint of related activities. Plant proteomics arises as a response to these problems, and through research and the application of new technologies, it attempts to enhance areas of food science that are fundamental for the optimization of processes. This review aims to present the different approaches and tools of proteomics in the investigation of new methods for the development of vegetable crops. In the last two decades, different studies in the control of the quality of crops have reported very interesting results that can help us to verify parameters as important as food safety, the authenticity of the products, or the increase in the yield by early detection of diseases. A strategic plan that encourages the incorporation of these new methods into the industry will be essential to promote the use of proteomics and all the advantages it offers in the optimization of processes and the solution of problems.

Plant breeding involving genetic engineering does not result in unacceptable unintended effects in rice relative to conventional cross-breeding

Advancements in -omics techniques provide powerful tools to assess the potential effects in composition of a plant at the RNA, protein and metabolite levels. These technologies can thus be deployed to assess whether genetic engineering (GE) causes changes in plants that go beyond the changes introduced by conventional plant breeding. Here, we compare the extent of transcriptome and metabolome modification occurring in leaves of four GE rice lines expressing Bacillus thuringiensis genes developed by GE and seven rice lines developed by conventional cross-breeding. The results showed that both types of crop breeding methods can bring changes at transcriptomic and metabolic levels, but the differences were comparable between the two methods, and were less than those between conventional non-GE lines were. Metabolome profiling analysis found several new metabolites in GE rice lines when compared with the closest non-GE parental lines, but these compounds were also found in several of the conventionally bred rice lines. Functional analyses suggest that the differentially expressed genes and metabolites caused by both GE and conventional cross-breeding do not involve detrimental metabolic pathways. The study successfully employed RNA-sequencing and high-performance liquid chromatography mass spectrometry technology to assess the unintended changes in new rice varieties, and the results suggest that GE does not cause unintended effects that go beyond conventional cross-breeding in rice.

A simple and accurate PCR method for detection of genetically modified rice

BACKGROUND

Legislation regulating for labeling and use of genetically modified (GM) crops are increased considerably worldwide in order to health and safety assurance of consumers. For this purpose, a polymerase chain reaction (PCR) method has been developed for detection of GM rice in people's food diet.

METHODS

In this study, eighty-one non-labeled rice samples were collected randomly from different market sites of Tehran, Iran. In order to analysis, rice genomic DNA was extracted using MBST DNA extraction kit and subsequently, sucrose phosphate synthase (SPS) gene was used to confirm the quality of extracted DNA. Then, cauliflower mosaic virus (CaMV) 35S promoter and Agrobacterium nopaline synthase (NOS) terminator were selected as screening targets for detection of GM rice sequences by PCR.

RESULTS

According to our results, 2 out of 81 (2.4%) samples tested were positive for CaMV 35S promoter while no positive result was detected for NOS terminator.

CONCLUSION

The obtained data indicated that this method is capable to identify the GM rice varieties. Furthermore, it can demonstrate the possibility of the presence of GM rice in Tehran's market, thus putting emphasis on the requirement for developing a precise approach to evaluate this product.

Comparative Proteomic and Nutritional Composition Analysis of Independent Transgenic Pigeon Pea Seeds Harboring cry1AcF and cry2Aa Genes and Their Nontransgenic Counterparts

Safety assessment of genetically modified plants is an important aspect prior to deregulation. Demonstration of substantial equivalence of the transgenics compared to their nontransgenic counterparts can be performed using different techniques at various molecular levels. The present study is a first-ever comprehensive evaluation of pigeon pea transgenics harboring two independent cry genes, cry2Aa and cry1AcF. The absence of unintended effects in the transgenic seed components was demonstrated by proteome and nutritional composition profiling. Analysis revealed that no significant differences were found in the various nutritional compositional analyses performed. Additionally, 2-DGE-based proteome analysis of the transgenic and nontransgenic seed protein revealed that there were no major changes in the protein profile, although a minor fold change in the expression of a few proteins was observed. Furthermore, the study also demonstrated that neither the integration of T-DNA nor the expression of the cry genes resulted in the production of unintended effects in the form of new toxins or allergens.

Comparative nutritional compositions and proteomics analysis of transgenic Xa21 rice seeds compared to conventional rice

Transgenic rice expressing the Xa21 gene have enhanced resistant to most devastating bacterial blight diseases caused by Xanthomonas oryzae pv. oryzae (Xoo). However, identification of unintended modifications, owing to the genetic modification, is an important aspect of transgenic crop safety assessment. In this study, the nutritional compositions of seeds from transgenic rice plants expressing the Xa21 gene were compared against non-transgenic rice seeds. In addition, to detect any changes in protein translation levels as a result of Xa21 gene expression, rice seed proteome analyses were also performed by two-dimensional gel electrophoresis. No significant differences were found in the nutritional compositions (proximate components, amino acids, minerals, vitamins and anti-nutrients) of the transgenic and non-transgenic rice seeds. Although gel electrophoresis identified 11 proteins that were differentially expressed between the transgenic and non-transgenic seed, only one of these (with a 20-fold up-regulation in the transgenic seed) shows nutrient reservoir activity. No new toxins or allergens were detected in the transgenic seeds.

Breeding of ozone resistant rice: relevance, approaches and challenges

Tropospheric ozone concentrations have been rising across Asia, and will continue to rise during the 21st century. Ozone affects rice yields through reductions in spikelet number, spikelet fertility, and grain size. Moreover, ozone leads to changes in rice grain and straw quality. Therefore the breeding of ozone tolerant rice varieties is warranted. The mapping of quantitative trait loci (QTL) using bi-parental populations identified several tolerance QTL mitigating symptom formation, grain yield losses, or the degradation of straw quality. A genome-wide association study (GWAS) demonstrated substantial natural genotypic variation in ozone tolerance in rice, and revealed that the genetic architecture of ozone tolerance in rice is dominated by multiple medium and small effect loci. Transgenic approaches targeting tolerance mechanisms such as antioxidant capacity are also discussed. It is concluded that the breeding of ozone tolerant rice can contribute substantially to the global food security, and is feasible using different breeding approaches.

Promise and issues of genetically modified crops

The growing area of genetically modified (GM) crops has substantially expanded since they were first commercialized in 1996. Correspondingly, the adoption of GM crops has brought huge economic and environmental benefits. All these achievements have been primarily supported by two simple traits of herbicide tolerance and insect resistance in the past 17 years. However, this situation will change soon. Recently, the advance of new products, technologies and safety assessment approaches has provided new opportunities for development of GM crops. In this review, we focus on the developmental trend in various aspects of GM crops including new products, technical innovation and risk assessment approaches, as well as potential challenges that GM crops are currently encountering.