Genetically modified (GM) tomatoes look much the same as traditional varieties. But are they? By comparing the chemical diversity of strains of GM tomatoes with a control strain and traditional reference cultivars, a research team in Japan has developed a way to distinguish between them.
Consumers need to be confident that GM tomatoes are safe, so initial risk assessments must show that they are ‘substantially equivalent’ to traditional varieties in their chemical make-up. Scientists can then focus on those chemicals, or ‘metabolites’, found only in particular GM varieties for toxicological testing.
As a case study, the team—led by Kazuki Saito of the RIKEN Plant Science Center in Yokohama—focused on GM tomatoes over-expressing a foreign gene encoding miraculin, a substance normally found in a tropical plant but not tomatoes. Miraculin is a glycoprotein—a protein with short carbohydrate side chains. It has the remarkable ability to make sour foods taste sweet. “Miraculin has fewer calories than sugar and has potential as a natural sweetener and flavor enhancer,” Saito notes.
Metabolism refers to the processes involved in maintaining life, including the building and breakdown of proteins, nucleic acids and carbohydrates. Complex metabolic pathways involve many enzymes and the chemical constituents of cells and tissues are in constant flux.
Whereas genomics provides an overview of the genetic composition of an organism, ‘metabolomics’ can give a snapshot of biochemical status. “We applied metabolomic techniques to compare the chemical diversity of GM tomatoes to that of traditional varieties,” Saito explains. Because there is currently no single technique for separating and characterizing all metabolites, the researchers used a range of metabolomic techniques to assess the chemical diversity of GM tomatoes over-expressing miraculin.
“Our multi-platform approach allowed us to identify metabolites in both types of tomato in an automated manner, and to evaluate variation between them using robust statistical methods,” says Saito.
The researchers found that the ripening GM tomatoes had a reproducible metabolic signature, and that over 92% of their metabolites showed an acceptable range of variation similar to that of the traditional varieties.
“Our aim was not to show that the GM tomatoes are safe, but rather to examine the chemical diversity of GM tomatoes compared with natural variants, and to possibly narrow down the list of potentially problematic metabolites as a guide to further investigation,” explains Saito.
The team believes that their multi-platform approach could be applied to any GM organism as a start to objective risk assessment.
The corresponding author for this highlight is based at the Metabolomics Research Division, RIKEN Plant Science Center
 Kusano, M., Redestig, H., Hirai, T., Oikawa, A., Matsuda, F., Fukushima, A., Arita, M., Watanabe, S., Yano, M., Hiwasa-Tanse, K., Ezura, H. & Saito, K. Covering chemical diversity of genetically-modified tomatoes using metabolomics for objective substantial equivalence assessment. PLoS ONE 6, e16989 (2011).
UNH researchers create a more effective hydrogel for healing wounds
21.11.2018 | University of New Hampshire
Removing toxic mercury from contaminated water
21.11.2018 | Chalmers University of Technology
Innsbruck quantum physicists have constructed a diode for magnetic fields and then tested it in the laboratory. The device, developed by the research groups led by the theorist Oriol Romero-Isart and the experimental physicist Gerhard Kirchmair, could open up a number of new applications.
Electric diodes are essential electronic components that conduct electricity in one direction but prevent conduction in the opposite one. They are found at the...
Max Planck researchers revel the nano-structure of molecular trains and the reason for smooth transport in cellular antennas.
Moving around, sensing the extracellular environment, and signaling to other cells are important for a cell to function properly. Responsible for those tasks...
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
19.11.2018 | Event News
09.11.2018 | Event News
06.11.2018 | Event News
21.11.2018 | Life Sciences
21.11.2018 | Medical Engineering
21.11.2018 | Physics and Astronomy