Strategies to detect unauthorized genetically modified organisms in food and feed chain

<p>To guarantee the traceability on the market and the freedom of choice for<br /> consumers, genetically modified organisms (GMO) legislations have been<br /> established in many countries, including in Europe (EU). However, the<br /> implementation of these legislations by the enforcement laboratories is becoming<br /> complex due mainly to the increasing number and diversity of GMO. To cope<br /> with the problematic of EU unauthorized GMO, this PhD aims to improve and<br /> strengthen the existing GMO detection system using high-tech approaches.<br /> First, as a study case, an overview of genetically modified (GM) rice, developed<br /> around the world was carried out to collect information related inter alia<br /> on elements found in their transgenic cassette. Second, according to this<br /> information, key targets, frequently found in GMO (p35S and tNOS) or<br /> exclusively observed in EU unauthorized GMO (t35S pCAMBIA), were selected<br /> to develop a strategy allowing to detect and characterize a broad range of<br /> GMO. This strategy, fully integrated in the GMO routine analysis, consists<br /> to characterize sequences surrounding detected key transgenic elements using<br /> a DNA walking approach. By this way, the acquisition of sequences from<br /> the junction between the transgenic cassette and the plant genome as well as<br /> the associations of elements typically found in transgenic constructs allow to<br /> confirm the presence of GMO in food/feed matrices. Due to its good performance<br /> thoroughly assessed via several unprocessed and processed food/feed matrices,<br /> this strategy represents a key tool, easily implementable by the enforcement<br /> laboratories. With the aim to even more simplify the workflow and increase the<br /> throughput of this strategy, the sequencing step was performed using the Next<br /> Generation Sequencing (NGS) technology instead of the Sanger technology.<br /> In parallel, the detection of GMO in alimentary matrices using exclusively the<br /> NGS technology, through a whole genome sequencing (WGS) approach, was<br /> also investigated. As this last approach does not theoretically require any prior<br /> information about the targeted sequences, GMO composed only of unknown<br /> transgenic elements could be detected.</p> <p>This work has thus allowed to provide additional strategies to the current GMO<br /> detection system in order to characterize a larger spectrum of GMO, both<br /> authorized or not.</p>