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).
Gene therapy shows promise for treating Niemann-Pick disease type C1
27.10.2016 | NIH/National Human Genome Research Institute
'Neighbor maps' reveal the genome's 3-D shape
27.10.2016 | International School of Advanced Studies (SISSA)
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
27.10.2016 | Materials Sciences
27.10.2016 | Physics and Astronomy
27.10.2016 | Life Sciences