DNA extraction techniques compared for accurate detection of genetically modified organisms (GMOs) in maize food and feed products

Research Progress of Nucleic Acid Detection Technology for Genetically Modified Maize

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.

Screening of P-35S, P-FMV, and T-NOS genetic elements in microwave-treated genetically modified cereal flours

BACKGROUND

Reliable and efficient methods for detecting genetically modified organisms (GMOs) in unprocessed and processed food will be essential for establishing an effective system for traceability all along the supply chain. It is important to understand the detection of GMOs following microwave treatment, which is a common processing method used in various food products such as flours. Therefore, this study aimed to detect the presence of Cauliflower mosaic virus (CaMV) 35S promoter (P-35S), Figwort mosaic virus (FMV) promoter (P-FMV), and T-NOS (nopaline synthase terminator) genetic elements in DNA samples from untreated and microwave-treated genetically modified (GM) cereal flour samples using the qualitative polymerase chain reaction (PCR) based screening method.Please confirm if the author names are presented accurately and in the correct sequence (given name, middle name/initial, family name). Author 1 Given name: [Begüm Zeynep] Last name [Hançerlioğulları]. Also, kindly confirm the details in the metadata are correct. The author names were presented accurately and in the correct sequence (given name, middle name/initial, family name).  Author 1 Given name: [Begüm Zeynep] Last name [Hançerlioğulları]. Author 2 Given name: [Remziye] Last name [Yılmaz]. The details in the metadata are correct.

METHODS AND RESULTS

DNA was extracted from all samples, and the efficiency of the qualitative PCR screening technique was tested by the verification studies. We performed an inhibition study with plant-specific actin (ACT) gene to the effectiveness of confirming the DNA extraction method. Then, we made the confirming of the qualitative PCR system by method performance testing criteria. The high quality and quantity of the DNA extracts from untreated and microwave-treated flour samples indicated the applicability of qualitative PCR screening assays. The results showed that microwave radiation does not significantly impact the genetic element screening in flour materials.

CONCLUSION

Untreated and microwave-treated flour samples had amplifiable DNA for the simultaneous screening of three genetic elements. The qualitative screening tests conducted in this study produced dependable outcomes, thus, can be successfully used for monitoring in control laboratories.

A Modified SDS – Based Method Applied for Extraction of High-Quality DNA from Raw Corn and Roasted Soybean

The probability of contamination of non-transgenic varieties with genetically modified (GM) products increase as a result of global expansion of areas sown with transgenic crops. DNA-based methods as accurate, efficient and reliable methods are preferable for detection of GM material in raw or highly processed foods. Isolation of high quality DNA with a suitable and efficient DNA extraction protocol is crucial for getting precise results in DNA amplification. In this study, we performed modifications of previously known Sodium dodecyl sulfate (SDS)-based DNA extraction method regarding the incubation period, DNA pellet washing and addition of organic solvent extraction, to improve DNA quality and to reduce costs. Raw corn kernels and roasted soybean seed were used as samples. DNA was extracted following three protocols, modifications of Edwards protocol. The type of detergent used in raw corn sample did not cause significant effects on extracted DNA yield and purity, while in roasted soybean samples the 2% (w/v) SDS lysis buffer gave the highest DNA yield. The additional incubation step raised the DNA yield from raw corn for 121%, while the purest DNA from soybean sample was obtained using organic solvent extraction. Electrophoretic determination of DNA integrity showed varying degree of DNA smearing from roasted soybean. Contrary, all extraction protocols used on raw corn kernels produced a high molecular weight DNA. Thus, our in-house DNA extraction protocol is as efficient but more cost effective compared to commercial kits and can be used for raw corn, while the protocol for roasted soybean needs further improvement.

Safety Assessment of Genetically Modified Feed: Is There Any Difference From Food?

Food security is one of major concerns for the growing global population. Modern agricultural biotechnologies, such as genetic modification, are a possible solution through enabling an increase of production, more efficient use of natural resources, and reduced environmental impacts. However, new crop varieties with altered genetic materials may be subjected to safety assessments to fulfil the regulatory requirements, prior to marketing. The aim of the assessment is to evaluate the impact of products from the new crop variety on human, animal, and the environmental health. Although, many studies on the risk assessment of genetically modified (GM) food have been published, little consideration to GM feedstuff has been given, despite that between 70 to 90% of all GM crops and their biomass are used as animal feed. In addition, in some GM plants such as forages that are only used for animal feeds, the assessment of the genetic modification may be of relevance only to livestock feeding. In this article, the regulatory framework of GM crops intended for animal feed is reviewed using the available information on GM food as the baseline. Although, the majority of techniques used for the safety assessment of GM food can be used in GM feed, many plant parts used for livestock feeding are inedible to humans. Therefore, the concentration of novel proteins in different plant tissues and level of exposure to GM feedstuff in the diet of target animals should be considered. A further development of specific methodologies for the assessment of GM crops intended for animal consumption is required, in order to provide a more accurate and standardized assessment to the GM feed safety.

Monitoring the prevalence of genetically modified maize in commercial animal feeds and food products in Turkey

BACKGROUND

EU legislation strictly controls use of genetically modified (GM) crops in food and feed products, and requires them to be labelled if the total GM content is greater than 9 g kg(-1) (for approved GM crops). We screened maize-containing food and feed products from Turkey to assess the prevalence of GM material.

RESULTS

With this aim, 83 food and feed products - none labelled as containing GM material - were screened using multiplex real-time polymerase chain reaction (PCR) for four common GM elements (35S/NOS/bar/FMV). Of these, 18.2% of feeds and 6% of food samples tested positive for one or more of these elements, and were subjected to event-specific PCR to identify which GM organisms they contained. Most samples were negative for the approved GM events tested, suggesting that they may contain adventitious GM contaminants. One sample was shown to contain an unapproved GM event (MON810, along with GA21) at a concentration well above the statutory labelling requirement.

CONCLUSION

Current legislation has restricted the penetration of GM maize into the Turkish food industry but not eliminated it, and the proliferation of different GM events is making monitoring increasingly complex. Our results indicate that labelling requirements are not being followed in some cases. © 2015 Society of Chemical Industry.